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Yes, that’s right. The Industrial Strength B2B Blog has moved to a new url and a new website host. The new url is http://www.industrialstrengthb2b.com and you’ll find the same information-rich articles and tech tips relating to power and industrial equipment.

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The Pollution Preventing Powers of Thermal Oxidizers

Heavy industries transform material from the earth. The material are usually combinations of organic and inorganic materials.

As we know chemistry is sub divided into ‘organic” and “inorganic”. Organic chemistry is defined as “A discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen…” [source]

The word “organic” implies those materials that are seen to be originally derived from plants.

Whenever we work with materials from the earth and recombine using heat and pressure, we drive off gases — fumes and smoke — that are both organic and inorganic. These by-products of transformation are those things that when carried in the air become acid rain, smog, or noxious odors — what we call generally term air pollution.

To avoid the harmful effects of these discharges industries are mandated and regulated to capture and control these releases.

For those processes where the discharge is primarily particulate-based process guys use electrostatic precipitators (ESPs).

For those processes where the discharge is primarily organic and gaseous based we typically use thermal oxidizers.

We will talk about ESPs and scrubbers at some time in the future but for now I want to concentrate on air-borne organic compounds controlled using thermal oxidizers.

The organic gaseous air stream are labeled “Volatile-Organic-Compounds” or “VOCs” because they are volatile ie possess a tendency to vaporize and are organic (contain carbon and hydrogen). Examples of VOCs are the fumes from oil based paint used in a manufacturing plant’s paint shop, to odors coming from a sewage treatment plant to a food processing company such as a distillery. In each case as these organic compounds are airborne they can enter the lungs and bloodstream of people and may cause harm.

Sometimes they are pleasant such as a bakery. Other times not so pleasant like a factory converting hydrocarbons into plastic products.

But in all cases because they are organic materials they will have a heat value. In essence they are a fuel and can be treated by being burned. A thermal oxidizer accomplishes this by using high heat in a controlled environment to destroy the VOCs. The destroyed VOCs are turned them into water vapor and carbon dioxide, which are much safer, before being released into the atmosphere.

If there is a fair amount of VOCs with higher heat value — hence a higher fuel value — they can self combust in units call “regenerative thermal oxidizers”. These units may use a small amount of natural gas to get the process started and from there on the organic material off-gas sustains the reaction into water and CO2.

Sometimes however the VOCs are so dilute, or the fuel value within the organic material is so low, that the controlled burn must happen with extra heat added – typically natural gas as a supplement fuel. In these cases the type of thermal oxidizer is termed a “recuperative thermal oxidizer”.

However in this last case using catalyst technology we can often enhance the heat value of the air pollution stream to be a self-sustainable burn. In these types of “concentrator thermal oxidizers” a catalyst is used to accumulate the organic material from the very diffuse VOC-laden air stream. The catalyst is then heated to liberate the collected, organic compounds into a secondary air flow stream that has a much lower air flow.

Because the air flow is much lower than the higher original air flow — but with the same amount of organic VOC content — the concentration of the organic compounds is higher i.e. the parts per million (or ppm) of the organic material is higher.

As we get the ppm higher it will approach the lower explosive limit (LEL). As we get closer to the LEL we get closer to the point at which it will burn in a self-sustaining manner. And if we can get the concentrated air stream above the LEL it will be self-sustaining thereby negating the need for supplemental natural gas.

In this manner, the cost of operating the thermal oxidizer is decreased radically as fuel use in a recuperative unit can be significant and therefore expensive.

In fact, retrofitting recuperatives into regenerative units or catalyst-enhanced concentrator regeneratives can save a ton of operational dollars and is well worth exploring.

Particularly as burning natural gas — although considered a clean fuel — also impacts the environment.

Heavy Duty Photo of the Week: Hudson Ward – 2

Hudson Ward – 2, originally uploaded by Foto43.

Interesting tone mapping treatment to this photograph. Taken on a February day at Goole Dockside, East Yorkshire.

Have a nice weekend everyone.

The Heat Is On (Air Cooled Heat Exchangers will fix that)

In Greek mythology Prometheus was credited with stealing fire from the gods and bringing it to man. Similarly in various Native North American tribes the mythology talks of fire being stolen by different life forms — Coyote, Dog, and the Hare as well as others and bringing it to man. Fire was such an important to tool to early man that stories were told to explain how it came to be in our possession.

There is no doubt that the harnessing of fire has transformed our world. Because without fire there could not have been an industrial revolution. Industrial processes consume a great deal of energy and specifically energy from fire. Heat is often required to convert materials from a primary form into secondary, secondary into tertiary and higher forms. Common processes are ore into iron or primary metals, iron into steel, and steel into hot rolled sheets for automobiles.

Once the transformation process is complete in most cases the heat must be dissipated. Either so that the process can continue, or so that the finished product can be shipped safely. Sometimes being left in a warehouse to cool naturally is all that is required, but more often than heat must be dissipated rapidly.

When cooling condensate from a power plant, equipment such as shell-and-tube heat exchangers may be used to remove heat from the saturated steam/condensate to cold water – often to a body of water like a lake or river. As regulations tighten over thermal pollution more plants are moving towards rejecting their heat to the atmosphere especially if there is a risk of the hot fluids, say from a chemical process, leaking into and contaminating the water body. In these cases air-cooled heat exchangers, or “fin fans”, can be used to transfer waste heat from a hotter liquid to the cooler ambient air.

Whether a shell and tube exchanger or a fin-fan, the physics of the heat transfer are fairly similar.

At the simplest level when heat is transferred whatever leaves a system it must go into its surroundings. For a fin-fan, the heat removed from a process liquid goes into the atmosphere.

The energy transactional relationship expressed in words is:

The Mass Flow of Liquid multiplied by the Specific Heat of the Liquid multiplied by the Change in temperature in the Liquid (incoming compared with outgoing) MUST EQUAL The Mass Flow of the Cooling Air multiplied by the Specific Heat of the Air multiplied by the Change in temperature of the air.

This is represented in equation form as…

Energy transaction represented in equation form

Where:

Incidentally, this also applies to cooling of solid materials, such as red-hot steel, coming off a hot rolled line where air is blown on hot surfaces. These very hot solid forms will have a blast of ambient air or chilled air to take away the temperature of the metal.

(In the case of red-hot steel, heat will also be carried away by conduction through the rollers, as well as radiation to the surroundings.)

Looking at the above equation the mass of cooling air drives the heat removal transfer. Often engineers and operators will speak in ‘air volume’ but ultimately it is the mass of the air that does the “work” of heat removal.

For a fin-fan designer moving the largest mass of air over the smallest fin-tube surface area is the main goal in order to minimize capital costs. Other considerations however are low noise and low pressure drop through the cooling coils. This means increasing the coil area and slowing the air velocity. So competing parameters and considerations exist.

To increase the heat transfer through the metal of the fin tubes the thinner the walls of the tubes the better the heat conductivity and therefore the higher the heat transfer. With corrosion (and to a degree erosion) taking place inside the tubes, the thicker the tube wall the longer the life of the fin coils. So again other competing parameters and considerations exist and a balance of heat transfer to longevity must be struck.

Sometimes both shell-and-tube heat exchangers work in conjunction with air-cooled heat exchangers. For example say hot smelter acid needs to be cooled to go back into the smelting process. Because the acid is very corrosive, a shell-and-tube exchanger made from corrosion resistant materials suited for extreme environments (C276, Hastelloy, Inconel, etc.) will be used to transfer its heat to a secondary cooling loop. Often a glycol solution is used to avoid freezing within the secondary loop and because of the liquid they are also called “glycol coolers”.

The secondary loop goes through the air-cooled heat exchanger to return the secondary cooling fluid back to its lower temperature state, so it can do work of heat removal in the shell-and-tube exchanger.

The movement and control of heat in processes is critical to optimizing industrial processes and a great deal of thought goes into the technologies.

If you have an air-cooled heat exchanger application you would like to talk about please contact www.aircooledheatexchangers.net to discuss how to size one that will fit area limitations and take into account life-cycle costs, reliability, maintainability and noise considerations.

Ask the Experts about Industrial Equipment

I was recently copied on email that sums up nicely the Dec. 10th entry. Some of it is paraphrased to shrink it down.

Q: I have a technical question about the combustion stove fan that we have purchased recently from your company in 2004.

Due to the current situation, we need to operate at lower production and as a result we require less combustion air.

As the combustion fans were sized larger at present the louvers are 100% closed. There is still small gaps between the louvres causing some air to push through.

1. Are the fans intentionally designed to leave some gaps/openings, even though the louvers are 100% closed? If so, what is the reasoning behind it?
2. Is it possible for us to reduce the open area in order to reduce the air flow? Is there any concern to the integrity of the fans (vacuum effect, build up of pressure, etc) if we close up the gaps?
3. What happens if the fan is running and we completely seal all the gaps?
4. What other options can we do to reduce the air flow while maintaining control?

A: The questions you raise are all very good ones. Let me first start off by clarifying the purpose or function of the inlet damper. The inlet damper’s role in the system is to modulate the volume or flow through the fan with turn down ratios of up to 10:1 dependent on fan design and selection criteria.

Standard dampers have a leakage rate of 4-10% and low leakage dampers are designed for 2-5% leakage at the fully closed position.

In your specific case, the fans were not designed to run at very low (less than 10:1 turn down). Non-optimal flow conditions and excessive vibration can develop at ultra low flows that can lead to mechanical damage if left alone without any supervision. At the very least, the heat generated from re-circulation of air inside the fan casing could lead to over-heating of the impeller as the kinetic energy is being added by the impeller but there is nowhere for the heat to escape.

I suspect that this is not the only fan at your mill facing these challenges as production is cut back to contend with current market supply and demand. Which brings me back to the primary design intent of the damper and it’s operating range vs. its efficiency window.

As mentioned above the damper is capable of modulating flow very well between approximately 10% and 100% flow. A damper on the inlet side is designed to reduce the power consumption or improve the efficiency of the fan as well as modulate flow, compared to an outlet damper that simply adds additional system pressure to the outlet of the fan to control the discharge volume of the fan.

The “efficiency window” of an inlet damper is in the neighborhood of about 60-100% open (0-40% closed) depending on fan type or design. Once the inlet damper is closed more than this the inlet damper begins to mimic the characteristics of an outlet damper. In other words it provides only artificial static pressure to the fan system and as a result the fan efficiency plummets. When a fan is running with dampers fully closed the efficiency is less than 15%, and likely less than 10%.

At approx. $60,000 per year for each 100 hp used, inefficiency costs can add up very quickly. Please also remember that fans and pumps are the two largest power consumers on the grid in the industrial market and should be the first place to look to save money.

We can help you with either a mechanical or electrical solution to your current operational requirements. These range from the various variable speed or reduced speed technologies to re-sizing the impeller and/or motor to match you current needs.

We would be happy to meet with you in improving the efficiency of your fans for your reduced production requirements of today and your record-breaking production runs of tomorrow.

Sincerely,

Mark Glover
Vice President
Canadian Buffalo

Note: Do you have any questions related to heavy duty industrial equipment? Email us , and we’ll answer your question in our next “Ask the Expert” segment.

When is a 100 horsepower motor not a 100 horsepower motor?

Variable Frequency drives (VFDs), or Variable Speed Drives (VSDs) are excellent electrical devices that offer greater process control, as well as save energy.

The advantage of speed control on a fan is that it will deliver the required flow necessary for the process without wasteful over-delivering, provided that the fan and VFD are sized correctly.

VFDs work by changing the frequency of the alternating current that the motor “sees”. In Canada and the US the alternating current operates at 60 Hz or cycles per second (note in many other countries such as South America and Europe the electrical grid operates at 50 Hz). If the motor shows 1800 rpm on the nameplate that indicates that the motor is a “4-pole motor” and will operate at 1800 rpm1. – when connected directly to the electrical motor control panel.

If however you put a VFD in the line you can adjust the frequency to anything between 10 hz2. and 90 Hz and the VFD will operate in a linear fashion between the two ranges.

As an example if the VFD is set to deliver a frequency of 30 Hz the motor will run at half its nameplate speed or 900 rpm. Similarly if 45 Hz then 3/4 the operating speed or 1350 rpm. This is pretty straightforward and most people know this.

But here’s the thing.

Although a motor can run at different speeds the horsepower the motor generates is also
proportional to the speed between the lower limit and its and nameplate speed (also called synchronous speed).

This is where people can run into problems. A standard industrial induction motor generates a constant torque within the operating range (somewhere around 20% to 100% of synchronous speed). As motor horsepower is the resultant of torque and speed and while torque may be constant, because the speed varies so does its ability to deliver hp.

Only when you hit 100% of the grid frequency (i.e. 60 Hz in the US) can the motor develop the full 100 hp stamped on the motor.

So in all practicality if you have a 100 hp motor as per the motor nameplate and the VFD is supplying power to the motor with a frequency less than 60 Hz you don’t have a 100 hp motor anymore, regardless of what it says on the nameplate. You have reduced its ability to deliver that hp by slowing it down through frequency control.

This may be tricky to grasp because the nameplate clearly says 100 hp.

But if you think of every frequency pulse as an energy shot similar to combustion stroke in a car engine and if you have half the pulses, you have only half the energy shots to do useful work.

When the required hp is higher than the available hp it usually shows up as tripping of the starter fuses, or an amp reading showing overloading of your MCC/motor.

The first comment might be “the fan is drawing too much power”, when it would be much more accurate to say, “the motor isn’t delivering enough horsepower”.

Let’s give an example. If you require 80 hp at 1300 rpm for a process and if a VFD is speed-controlling a 100 hp/1800 rpm motor, then at 1300 rpm the available power will only be 72 hp. Because1300/1800 x 100 = 72 hp.

The motor may in fact carry the load because many motors have a 15% service factor, but the amperage will be higher than the amperage on the nameplate because the motor needs to take in more amperage to meet the hp requirement.

Say you are in this situation, then what?

Okay here are some remedies to correct this. One is to increase the size of the 1800 rpm motor to a larger size. In this example a 125 hp motor will do, because 1300/1800 x 125 = 90 hp and 90 hp is more than enough to carry the load. But you will also need to upsize the fuses and possibly the VFD too.

Another way to have enough available hp is to keep the same hp but change the motor to a lower speed. A 1200 rpm motor will generate its nameplate horsepower at its nameplate speed and not lose any power as it goes above this point. So at 1300 rpm the motor will still generate 100 hp and be more than enough to carry the 80 hp requirement. In this way installing larger fuses isn’t required. There are also limits to over-speeding including mechanical — such as the motor bearing life and there is some loss of hp drop off with higher speed. So it is best to confer with the motor and VFD vendor to clarify what hp and speeds are available. This being said, over-speeding is becoming more commonplace in industry as people become comfortable about using the full potential of VFDs.

Another way to deliver the required hp at reduced fan speeds is to make proper use of mechanical advantage. If the fan is driven through a belt drive then simply ensure that the motor-fan drive ratios is set up to permit the motor to run fast enough in order to develop the necessary hp at the required fan speed. In this example to deliver 80 hp at 1300 rpm for the fan using a 100 hp 1800 rpm motor, the motor must be turning at least 80% of 1800 rpm or 1440 rpm.

And always if any questions feel free to put a comment in and we will reply.

1.Actually it will run slightly lower – somewhere between 1750 and 1795 rpm due to “slippage” but for the purposes of this entry we will ignore that.

2.Lower limits exist as heat generation at the motor can only be dissipated by operating at a minimum speed.

Heavy Duty Photo of the Week: 5 Stacks

5 Stacks, originally uploaded by lunchtimemama.

Just by looking at this photo, I can feel the crisp winter air on my face.

Wait a sec. It IS cold outside!

Have a safe and warm weekend everyone. Thank you for your readership!

P.S. Do you have a industrial-related photograph you’d like to share with the world? Please submit it and we’ll be happy to publish it.

The Problems of Selecting Equipment

Fans, pumps, boilers and furnaces etc. are used in most industrial processes to convert material from one form into another — such as iron into steel, or pulp-fiber into paper. The conversion of one material, or mixture of materials, to a more complex form is often measured in tons per unit of time (such as minutes, hours or days) and is called the throughput.

When sizing industrial equipment one starts from a known quantity of throughput. All of the ancillary equipment will then be designed and selected based on achieving that production value plus some percentage for future expansion.

But often the extrapolation from the known to the anticipated is when things can get out of hand, as projected values will often be hedged higher and higher again.

For instance, say we are dealing with a refinery that is cracking crude oil into the various hydrocarbons such as Bunker C Oil, gasoline or diesel.

Again the throughput is known or decided in advance, in other words how much crude oil will be processed at this unit.

From this, coupled with the knowledge of similar operating units, the ancillary equipment such as boiler fans etc will then be sized. We will look at fans as the example, but it can just as easily apply to any piece of process equipment.

The boiler operators who are involved with the operation are the closest on a day-to-day basis and are often the first people asked. They, in conjunction with the process engineering group, will look at historical data and based on their experience and using mass calculation equations, will give an opinion on the required fan volume at various temperatures and densities of air.

Because there is a lot of variability on the process from fluctuating densities of air to fluctuating varieties of crude oil and what cracking strategy can deliver the highest profit for the raw material they will want to err on the safe side which can be summed up as “more is better than less”.

This may then go to the overall area supervisor for final approval who looks at the results and will generally apply a contingency factor. From there it goes to the consulting engineering group who put together a myriad of components. When it comes to the fan they will generally apply another safety factor. Finally the bid request is issued and a fan engineer will size it often with a small over-sizing percentage for further contingency – not to mention that within the software program they use there is a hidden contingency allowance.

All want to make sure there is a bit of margin to cover any unknowns in the fan performance or in the data they have because the thinking is you can always throttle back but if the fan is too small then it gets expensive if you need a larger fan.

That is why if you walk through a boiler house in many industrial plants and look at the ID or FD fan’s variable-inlet-vanes or (inlet or outlet) louver dampers are choked or throttled way back because the fan although designed for some larger future flow is running at a significantly lower rating point..

When this operating condition exists then control of the process is difficult as the control actuator is cycling within a small band — say between 85% to 100% closed, rather than between a larger range such as 0% to 50% closed.

In terms of energy consumption the fan running throttled way back is using a lot more than required as the operating point does not line up near its maximum efficiency point – not to mention the added air pressure that must be artificially knocked down by the dampers. Many plants will run like this because it is time consuming to go back and resize for the present consumption.. There are many reasons but one main reason is lack of known data. If one can’t access data from a computer historically tracking the percentage open of the dampers people are reluctant to make a change in case it requires a lot more air volume under certain circumstances that they haven’t witnessed.

This is one reason why historically tracking parameters is a useful and cost saving tool.

Without good tracking but even with it is a justification to explore speed control. Using variable speed with a feedback loop based on a key parameter such as pressure or flow the fan will automatically slow down to deliver only the required amount of air.

There are issues to observe of course. Every situation is unique. Some processes will use speed control with vane control to hit multiple points of ratings because sometimes the system will need high pressure with lower flows.

Nevertheless with the cubed relationship between speed and power for fans and pumps (the Affinity Laws) reducing the speed by half will result in consumption of power being reduced to 1/8 of the power — (1/2) 3 or ½ x ½ x ½ = 1/8 th of original power.

So a powerful incentive exists to take those real offenders that are operating almost completely choked off and slowing them down to a speed capable of delivering maximum control and optimum efficiency.

Alternatives do exist as well to reduce to a fixed speed on fans with vane control. Adjusting belt drive sheave ratios will allow a fan to run slower and allow the vanes to operate in a less throttled back position. Similar strategies exist for direct drives fans without having to use VFDs. This is a bit more complex but options do exist.

As energy has a direct line to pollution doing our part only makes sense and as a bonus can have a very quick energy payback.

Tech Tip – Aerodynamics and Efficiencies of Different Fan Wheel Types

In our last Tech Tip we looked at the efficiency of different sized fans of the same type. Generally speaking, for the same service, a smaller fan running faster will have a lower first cost than a larger fan running slower. However it will likely consume more power than the larger fan.

Continuing in the efficiency theme we will look at the efficiency of different fan wheel types.

Aerodynamics of a fan has a huge impact on fan efficiency. A radial bladed wheel with an inlet scroll that improves inlet conditions, has a higher efficiency than an open paddle wheel design. A backward inclined fan wheel, also straight bladed, is better yet because of its aerodynamics. The best aerodynamic design – backward curved and air-foil blades – yield the best efficiencies.

While fan efficiency is an important parameter – since it has a direct effect on on-going energy costs – it is still only one of a number of parameters. In fact, there is no one fan for all conditions. Otherwise there would only be one type for all applications.

Let’s look at an example to illustrate this. For a dust collector fan, often a designer will insist that a radial bladed wheel is the only fan type to be used and there are some valid reasons. On a backward curved wheel material in the air-stream can build-up on the underside of the fan’s blade. This can produce imbalance that if left to run for any length of time can damage the fan. As radial bladed wheels have no contours to hold material it is considered to have a ‘self-cleaning’ blade and therefore, they are well suited for handling dust-laden air applications.

But for a fan that is situated after a properly working bag house, where the air is clean, using such a wheel will mean missed energy efficiency opportunities. For instance, using the duty from last episode, 25,000 cfm at 14″ static pressure and comparing a radial and backward curved design we would see the following:

 

Wheel Type / Size	Wheel Dia. (ins.)	Speed (rpm)	Efficiency (per cent)	HP	Installed Motor
Radial Blade / Size 331.	58	902	63.40%	86.9	100
Backward Curved / 7302.	36.5	1641	79.60%	69.1	75

1. The fan size number referred to is the inlet diameter.
2. The fan size number referred to is the wheel diameter x 20.

Looking at purchase and operating costs 3. we see:

(3. based on 10 cents/kwhrs - average of peak and demand charges).

Size	Fan	Motor	Purchase Cost	BHP	Energy Cost Per Year
33	$13,000	$4,000	$17,000.00	86.9	$ 60,221.42
730	$8,750	$3,250	$12,000.00	79.6	$ 47,886.08

 

In this particular case the backward curved fan is less expensive, although this is not always the case. The part to note is the savings in electricity of $12,335 per year. Many people resist employing more efficient wheels as they wish to avoid potential imbalance conditions, even where the risk tends towards the low side. In this example these savings can justify having a standby fan ready to be dropped into place should a problem occur.

Although one must consider all costs and certainly lost production costs can quickly outstrip savings, with Kyoto becoming a reality, it is likely that we will see more attention paid to exploring areas for energy savings.

Heavy Duty Photo of the Week: Industrial Fronds

Industrial Fronds, originally uploaded by Lost America.

A still operational industrial complex at Treasure Island Naval Base in San Francisco Bay.

Environmental Sustainability Leads to Economic Opportunities

There’s an insightful article on Environment Canada’s website about the impacts of poor air quality. In addition to health problems in humans, wildlife and even vegetation, air pollution can also have a significant impact on industry as well.

From the article:

What is important to remember is that these impacts on human health, the environment and the economy do not exist in isolation, they are linked. For instance, decreased forest productivity because acid rain has damaged the soil may lead to increased stresses on the pulp and paper job market.

Alternately, and in a more positive note:

the creation of new technology, knowledge and jobs to address air quality concerns can produce economic opportunities.

CB Power and Industrial Equipment provides heavy duty equipment that can improve energy efficiencies, control air polluting emissions and destroy hazardous gases for almost any industrial manufacturing operation.

Like you, we understand that companies who can reconcile the environment and the economy will derive enormous economic benefits, while those that continue to view the environment as a barrier to competitiveness will fall behind.

Interesting Facts about Solid Waste

While spelunking the dark recesses of the internet, I discovered an interesting article from the UCCP, University of California. I hope you find it interesting and informative as well.

In natural systems, there is no such thing as waste. Everything flows in a natural cycle of use and reuse. Living organisms consume materials and eventually return them to the environment, usually in a different form, for reuse. Solid waste (or trash) is a human concept. It refers to a variety of discarded materials, not liquid or gas, that are deemed useless or worthless. However, what is worthless to one person may be of value to someone else, and solid wastes can be considered to be misplaced resources. Learning effective ways to reduce the amount of wastes produced and to recycle valuable resources contained in the wastes is important if humans wish to maintain a livable and sustainable environment.

Solid waste disposal has been an issue facing humans since they began living together in large, permanent settlements. With the migration of people to urban settings, the volume of solid waste in concentrated areas greatly increased.

Ancient cultures dealt with waste disposal in various ways: they dumped it outside their settlements, incorporated some of it into flooring and building materials, and recycled some of it. Dumping and/or burning solid waste has been a standard practice over the centuries. Most communities in the United States dumped or burned their trash until the 1960s, when the Solid Waste Disposal Act of 1965 (part of the Clean Air Act) required environmentally sound disposal of waste materials.

 

SOURCES AND TYPES OF SOLID WASTE

There are two basic sources of solid wastes: non-municipal and municipal. Non-municipal solid waste is the discarded solid material from industry, agriculture, mining, and oil and gas production. It makes up almost 99 percent of all the waste in the United States. Some common items that are classified as non-municipal waste are: construction materials (roofing shingles, electrical fixtures, bricks); waste-water sludge; incinerator residues; ash; scrubber sludge; oil/gas/mining waste; railroad ties, and pesticide containers.

Municipal solid waste is made up of discarded solid materials from residences, businesses, and city buildings. It makes up a small percentage of waste in the United States, only a little more than one percent of the total. Municipal solid waste consists of materials from plastics to food scraps. The most common waste product is paper (about 40 percent of the total).

Other common components are: yard waste (green waste), plastics, metals, wood, glass and food waste. The composition of the municipal wastes can vary from region to region and from season to season. Food waste, which includes animal and vegetable wastes resulting from the preparation and consumption of food, is commonly known as garbage.

Some solid wastes are detrimental to the health and well-being of humans. These materials are classified as hazardous wastes. Hazardous wastes are defined as materials which are toxic, carcinogenic (cause cancer), mutagenic (cause DNA mutations), teratogenic (cause birth defects), highly flammable, corrosive or explosive. Although hazardous wastes in the United States are supposedly regulated, some obviously hazardous solid wastes are excluded from strict regulation; these include: mining, hazardous household and small business wastes.

 

WASTE DISPOSAL METHODS

Most solid waste is either sent to landfills (dumped) or to incinerators (burned). Ocean dumping has also been a popular way for coastal communities to dispose of their solid wastes. In this method, large barges carry waste out to sea and dump it into the ocean. That practice is now banned in the United States due to pollution problems it created. Most municipal and non-municipal waste (about 60%) is sent to landfills. Landfills are popular because they are relatively easy to operate and can handle of lot of waste material. There are two types of landfills: sanitary landfills and secure landfills.

In a sanitary landfill solid wastes are spread out and compacted in a hole, canyon area or a giant mound. Modern sanitary landfills are lined with layers of clay, sand and plastic. Each day after garbage is dumped in the landfill, it is covered with clay or plastic to prevent redistribution by animals or the wind.

Rainwater that percolates through a sanitary landfill is collected in the bottom liner. This liquid leachate may contain toxic chemicals such as dioxin, mercury, and pesticides. Therefore, it is removed to prevent contamination of local aquifers. The groundwater near the landfill is closely monitored for signs of contamination from the leachate.

As the buried wastes are decomposed by bacteria, gases such as methane and carbon dioxide are produced. Because methane gas is very flammable, it is usually collected with other gases by a system of pipes, separated and then either burned off or used as a source of energy (e.g., home heating and cooking, generating electricity). Other gases such as ammonia and hydrogen sulfide may also be released by the landfill, contributing to air pollution. These gases are also monitored and, if necessary, collected for disposal. Finally, when the landfill reaches its capacity, it is sealed with more layers of clay and sand. Gas and water monitoring activities, though, must continue past the useful life of the landfill.

Secure landfills are designed to handle hazardous wastes. They are basically the same design as sanitary landfills, but they have thicker plastic and clay liners. Also, wastes are segregated and stored according to type, typically in barrels, which prevents the mixing of incompatible wastes. Some hazardous waste in the United States is sent to foreign countries for disposal. Developing countries are willing to accept this waste to raise needed monies. Recent treaties by the U.N. Environment Programme have addressed the international transport of such hazardous wastes.

Federal regulation mandates that landfills cannot be located near faults, floodplains, wetlands or other bodies of water. In many areas, finding landfill space is not a problem, but in some heavily populated areas it is difficult to find suitable sites. There are, of course, other problems associated with landfills. The liners may eventually leak and contaminate groundwater with toxic leachate. Landfills also produce polluting gases, and landfill vehicle traffic can be a source of noise and particulate pollutants for any nearby community.

About 15 percent of the municipal solid waste in the United States is incinerated. Incineration is the burning of solid wastes at high temperatures (>1000ºC). Though particulate matter, such as ash, remains after the incineration, the sheer volume of the waste is reduced by about 85 percent. Ash is much more compact than unburned solid waste. In addition to the volume reduction of the waste, the heat from the trash that is incinerated in large-scale facilities can be used to produce electric power. This process is called waste-to-energy. There are two kinds of waste-to-energy systems: mass burn incinerators and refuse-derived incinerators.

In mass burn incinerators all of the solid waste is incinerated. The heat from the incineration process is used to produce steam. This steam is used to drive electric power generators. Acid gases from the burning are removed by chemical scrubbers.

Any particulates in the combustion gases are removed by electrostatic precipitators. The cleaned gases are then released into the atmosphere through a tall stack. The ashes from the combustion are sent to a landfill for disposal.

It is best if only combustible items (paper, wood products, and plastics) are burned. In a refuse-derived incinerator, non-combustible materials are separated from the waste. Items such as glass and metals may be recycled. The combustible wastes are then formed into fuel pellets which can be burned in standard steam boilers. This system has the advantage of removing potentially harmful materials from waste before it is burned. It also provides for some recycling of materials.

As with any combustion process, the main environmental concern is air quality. Incineration releases various air pollutants (particulates, sulfur dioxide, nitrogen oxides, and methane) into the atmosphere. Heavy metals (e.g., lead, mercury) and other chemical toxins (e.g., dioxins) can also be released. Many communities do not want incinerators within their city limits. Incinerators are also costly to build and to maintain when compared to landfills.

Heavy Duty Photo of the Week: Grangemounth Oil Refinery

Grangemounth Oil Refinery HDR, originally uploaded by Duncan_Smith.

Like a scene out of Blade Runner.

The Intelligence of Animals: A Trilogy

Written by Jim Wywrot

Experts talk about the instinct of animals and tend to downplay their intelligence. I think there is more intelligence in animals then in many experts. I want to talk about three animal s I came across.

This is a story of a bird.

 

It starts during an early morning walk to work. It was early fall and there were only a few people about but what caught my eye was a seagull. I am not sure why. It may have been the motion that caught my eye but I saw a seagull flying away carrying something round and yellow in its mouth.

 

Just then I walked by a pear tree. A few were scattered on the ground beneath. Mystery solved, I watched as the seagull flew away with its morning breakfast.

 

Another second I would have turned away, but just then I saw the seagull had dropped the pear. If I didn’t see it for myself I wouldn’t have believed it but the seagull banked hard to the left dropped into a steep dive and caught before it hit the ground. A grab like that is usually accompanied by shouts of “who da man”, but I just kept on walking.

The seagull came toward me climbed and turned in a circle resuming her course. I say female because that last manoeuvre was very graceful.

As it came close to spot where she had dropped it disaster appeared to repeat itself. The pear dropped again! Another hard bank. Another steep dive. Another awesome catch. “That must be one slippery pear”, I thought.

The seagull started to climb again and turned away to leave. I expected her to hold on much tighter this time and watched closely. I was in for a shock. She dropped it again!

Sharp bank, steep dive but third time was not a charm as it splattered on the ground.

That’s when it occurred to me. It wasn’t a slippery pear. She was just playing. Revelling in her aviation prowess. Or maybe she was simply showing off.

Now I know the experts will say it was not play. Just practising catching food as it comes in handy or whatever. You know like wolf cubs brothers fighting each other. Not for fun, but to hone skills for survival. Purely practical really.

I don’t know about that though. It sure looked like fun to me.

============================================================================

 

This is a story about a fish.

Years ago we were visiting a friend’s cottage on Lake Superior. Anyone who has been to Lake Superior knows it has two temperatures, cold and bloody cold.

It was a beautiful summer day as my six year old son and I walked along the beach. The waves were pounding its rhythm on the beach. We would walk into the water up to our knees but not much farther as the water was like ice.

As we walked down the beach, perhaps a mile, we came to a small pool that was about 15 ft from the lakes edge. The tides go up and down and as they recede sometimes small ponds are formed near the lakes edge and this was one of them. This particular was about 3 ft deep and 25 ft across.

The water being separated from the cold mass of the lake was much warmer and we waded in. Just then we noticed a school of minnows in the pond.

As we stood and watched, my son suggested digging a canal to link the pond to the lake.

Using our hands we started to dig a trench in the beach sand. Five minutes into it, our small trench allowed the first wave to travel up the beach and rather than dying on the lakeside of the beach, it continued into the pond, where the ripple from the wave spread across the pond. Now I know how Roosevelt felt when the Panama Canal was finished.

After two more waves the walls of the canal started to cave in, blocking the next waves path. We had to keep digging to keep the canal clear. But as we did we noticed one of the minnows had left its school and was now using our canal as a route to the lake!

Now we had a mission! We had to make the trench deeper so that the minnow could make it over the crest. We worked furiously. We dug but with each wave a bit of the walls would cave in and back-fill the trench. Each time Hector (we had named him by that time) did his part. As the wave came into the pond he made a mad dash upstream. The wave would not fill the trench deep enough and he ran out of water right at the top and had to turn around and scramble back to the pond.

We tried perhaps a dozen times. Each time Hector made his hell-bent-for-leather run.

We eventually had to give up, the difference in length and height was too much for a man and a small boy using, only their hands. Hector slid back into the school and we couldn’t pick him out from the crowd.

My son told me that we couldn’t leave until he got out, but I explained this part of Lake Superior sees changes in tides. The water would overtake the crest and he would finally be on his journey, with or without our help.

 

As we walked back, I thought about Hector. I wondered why out of 100 minnows, there was only one that was bound and determined to head out?

Experts tell us that safety in numbers is rule that fish follow. It’s an instinct thing. But this clearly didn’t fit the data.

Was Hector then, a minnow version of an entrepreneur? Striking out for bigger opportunities. Or was he just a truant? Playing hooky from school.

I thought about this as we walked back. It occurred to me when the experts look at anything, whether it is the stock market or behaviour of people and animals, most often they just look at group behaviour. It’s not that the individuals don’t count. It is just that they are too hard to explain.

Whatever the reason I am glad there are individuals in the world. It sure makes life more interesting.

============================================================================

This is a story about a mammal. Specifically a cat. One named Scooter. We rescued him from the pound when he was a kitten as company for our older cat.

When our older cat died he became our one and only cat. He maintained that role for many years. He made the trip from Ottawa to London in our car. We kept him in a travel cage. Somewhere around Woodstock he felt the need to stretch his legs so we let him out just as a large tanker truck was passing in the centre lane. I can remember him looking up at it as we travelled along the 401 at 100 kph, this huge truck rumbling beside us. When he looked around and realized he was on a three-lane highway he went right back into the cage. He was smart too as you can see.

When our kids were smaller they had a teenage babysitter who looked after them during the summer cat. The babysitter’s cat had kittens and the boys got to see the kittens and well you know the rest. Spud the cat arrived and became the junior cat.

The first meeting between Scooter and Spud was interesting. When Spud saw this huge cat he did the arch-the-back thing. This was probably laughable to Scooter who was 6 times his size. Scooter though was all patience and wisdom – a Buddha of a cat really – and gave the little purrish sound that meant, “All is cool little buddy.”

Scooter was a pacifist cat. Unlike others of his species he would be content to watch the birds and squirrels and other cats that visited our yard. Spud was more aggressive. Any cat that came over Spud would make sure they knew this was his turf.

One day I came from the front and as I opened the gate I could see Spud and the neighbour’s cat were engaged in cat-on-cat violence. I was just about to break it up when I caught Scooter sitting on the deck just watching the two, just like a referee.

When I noticed him, Scooter looked back at me for a second. Then he looked back at the fight. Then looked back at me for a bit longer then back to the fight. Not content one more check at me before he jumped up and into the fray. Two on one was too much and the neighbour’s kitty ran back to his yard.

I was never sure if Scooter was thinking “Oh the boss is here. Looks like this might be a good opportunity to get in a few licks. He’ll break it up if it gets out of hand.” But actually I think it was “Oh oh, the boss is here. I wonder if he thinks I am ignoring my duties and not defending the homestead. Better check. Yep looking right at me! Oh well here goes.”

The thought process was so completely obvious. Anyone with two eyes could tell it was not instinctive, that a risk vs. reward evaluation was in process. Should I go or not? Back and forth and then the decision reached. Grudgingly perhaps but reached all the same.

Experts say animals don’t have intelligence. You don’t need to be an expert to know things. You just need two eyes and a fully engaged mind. Maybe its time we told the emperor he has no clothes. After all it is a little cold out.

Heavy Duty Photo of the Week: SCP_31

SCP_31, originally uploaded by Pro-Zak.

Eerie yet oddly beautiful. Says Pro-Zak, “Water damage makes for great photography.”

Announcing New Web Site: www.TurbineTechnology.net

TurbineTechnology.net is the latest website asset of CB Power and Industrial Equipment, an industrial equipment representative office in Cambridge Ontario. The website offers information on Steam Turbines and related applications.

“I’m happy to announce the launch of TurbineTechnology.net, and to inform businesses in the industrial sector about Mechanology, the premier manufacturer of steam turbines”, says Jason Comely, Technology and Marketing Director of CB Power and Industrial Equipment. “Visitors will find the website is easy to read, navigate and will be able to extract the information they need in a timely manner.”

Of course, the website is an access point to timely expert support from experienced engineers. CB Power and Industrial Equipment has been helping businesses in the manufacturing sector since 1979.

Comely adds, “Users of TurbineTechnology.net will also like the easy information request form on each page. It’s part and parcel of the site’s streamlined design. We’re ready to assist anyone in the market for steam turbines.”

For more details on Mechanology’s steam turbines and their fast delivery times, visit TurbineTechnology.net.

Tech Tip – Wear and Tear of Fans, Pumps and Conveyor Belts

by Jim Wywrot P.Eng.

Equipment that comes in contact with abrasive materials such as fans, pumps,
conveyor belting etc. has three main aspects that impact on wear. The speed
at which the particles hit the surface, the hardness of the particle
relative to the hardness of the surface and the geometry, or angle of
attack.

Material moving equipment such as bucket elevators or road graders subject
to wear can be provided with wear plates. There is no one perfect material
for the wear plates to be used for all applications. In many cases it may be
the same material as the main equipment, but bolted in place for easy
replacement. The wear plate is then called sacrificial.

The same applies to fans that experience abrasive wear. In these cases wear
plates, such as checker plates of mild steel can be used and are often
bolted on to protect the wheel and housing steel from abrasive attack.

As the attack from abrasion goes up one needs to consider harder wear
protection. Harder materials are generally more brittle. A good everyday
example is a floor ceramic tile. Very tough to drill through, but can be
easily cracked with a hammer.

Toughness pertaining to materials means how susceptible it is to brittle
fractures. A material with high toughness would not be brittle. Plain mild
steel falls into this category. As abrasion levels increase, we need to
trade off toughness characteristics for increased hardness characteristics.

An example of progression would be mild steel checker plate to chrome
carbide, to tungsten carbide, to ceramic. There are more possibilities in
between. In addition the means of fastening is important because a failure
of the fastening mechanism will expose the unprotected metal to attack.
Every installation has to be evaluated individually and suitable engineered
plates provided.

The energy of the particle impact increases with speed so keeping this speed
lower reduces wear. It is not necessarily the rpm of the fan but the speed
of the blade at the tip that counts.

If your equipment is wearing out sooner than you feel it should, trust your
instincts and explore new techniques or newer technologies. Research what is
being done in your industry and what your industry is doing in other
countries. There are techniques unique to North America and those unique to
Europe. Through travel and telecommunications we now have easier access to
this information.

With any change there is also risk. Lee Iaccoa was asked how one makes a
decision to ensure success. He made the following statement – “One can never
have enough information to make a completely safe decision. One must
research it well, think hard, but ultimately one must make a ‘leap of faith’”.

Summing up, research well, build a case and remember to always have faith in
your detailed decision.

Tech Tip – Getting Maximum Life out of Bearings

Like any mechanical device, bearings wear out over time. This is unavoidable fact of life. What we want to talk about is getting the maximum life out of the bearings in your rotating equipment.

To start with there are five simple things one can do to maximize bearing life. These five steps are to keep your bearings Clean, Dry, Cool, and your equipment Balanced and Aligned.

Clean, Dry, Cool means addressing the lubrication issues of the equipment. For instance circulating oil systems are used when the heat build up at the bearing is more than a static oil system can radiate away. In this case the system provides external cooling. However, just like in a car, circulating oil must be changed periodically. Oil will deteriorate over time from heat, oxidation, catalytic reactions, and dirt or water contamination. It is a good idea to change the oil whenever it becomes dirty or cloudy.

Grit and dirt contamination act as abrasives and over time will remove the hard facing of the bearing. Once the hard facing is removed the bearing will quickly deteriorate to failure. Therefore it is important to keep the dirt contamination out.

In wet environments keeping bearings dry can sometimes be difficult. It is also important since water will separate the lubricant. If you notice a milky look to the grease being purged from the bearings it is an indication of contamination by water.

Balanced and Aligned refers to minimizing the destructive energies present when imbalance and misalignment are allowed to continue. Keeping these forces to a minimum greatly adds to extending bearing life. Many companies use vibration monitoring equipment to determine the severity of these forces or shut down the equipment if these energies get too large. As an example of vibration levels seen in the field, it is not uncommon to see vibration velocities of 0.10 in/sec or lower for initial operation, 0.30 in/sec for an alarm setting and 0.45 in/sec as the shut down setting for a heavy duty fan. However, as there are many applications it is always best to check with your fan supplier on these matters.

An example of using Clean, Dry, Cool, Balance and Align to extend the life of equipment was a process pump in a paper mill application suffering repetitive failures. It was felt that the location in the process subjected the bearings to high impact from foreign material going through the pump. Because of the frequency of repairs the pump was not looked after as well as other pumps, since the service people knew another failure would be occurring soon.

As a repeat offender this pump was singled out by the team to reduce down time. Initial steps focused on paying close attention to the motor alignment. In this case the use of laser alignment was employed. This one step had a marked impact and doubled the time between failures. After this success the team focused on improving the bearing seals to prevent suspected water and dirt contamination. Following these upgrades the pump no longer experienced frequent failures.

In closing Clean, Dry, Cool, Balanced and Aligned are five simple but important and fundamental steps to ensure that you get the most running life out of your equipment’s bearings.

Marcel Kamutzki is a professional engineer who has a long association with turbo-machinery.
Currently he is Engineering Manager at Daltec Canadian Buffalo fans in Guelph Ontario.

He can be reached at marcel@canadianbuffalo.com

Heavy Duty Photo of the Week: Double stack – VoxEfx

double stack – VoxEfx, originally uploaded by √oхέƒx™.

I can just feel the warm breeze pushing the clouds ;)

Building an Industrial-Sized Luxury Cruise Liner

Royal Caribbean isn’t letting a recession get in the way of their grand plans to build the world’s largest and most luxurious cruise liner. Their “Oasis Of The Seas” will launch in November 2009 featuring seven different neighborhoods with accommodation for 5,400 guests.

And get this: the ship is so large, it has seven themed neighbourhoods.

7 Energy Efficiency Myths Debunked

The emotional appeal of energy independence is undeniable—it suggests freedom from foreign oil and, therefore, from foreign entanglements. But over the past few years, veteran energy writer Robert Bryce argues, the political players who are promoting the concept of energy independence have created a set of false promises to bolster their campaigns and give such independence the appearance of credibility. In exclusive excerpts from his new book, Gusher of Lies, Bryce examines the facts behind those promises. Read the article.

Tech Tip – Handling Temperature Extremes

We live in a world of stress. So do machines. As engineers we account for the impact elevated temperatures will have on machinery components design within established known limits.

But it is important to not only account for temperature and temperature swings but also how fast temperature may change for a piece of equipment.

This is known as Rapid Delta T and something worth discussing.

For instance it is not uncommon for a process piece of equipment to see temperature extremes such as 800F, or higher, as well as starting at –40F temperatures

Equipment materials need to be selected to handle the temperature extremes. The lubricant and lubricant system must ensure the right viscosity at the cold end so that the bearings will operate properly while protecting the bearings and lubricant from overheating at the high end. In addition if the fan experiences the two temperature extremes within a very short period of time, then issues related to different rates of component expansion also have to be addressed.

Even though two components are made from the same material a thin component exposed to a source of heat will see a more rapid increase in temperature than a thick component. A backplate for instance is generally made of steel plate whereas the hub is often made of a massive piece of cast iron or steel forgings. Under rapid delta T conditions the thinner backplate will act as a conducting fin and grow quicker than the hub. When this uneven expansion takes place the stress is transmitted through the bolts or rivets and can actually shear through the backplate.

Similarly a cast iron hub often has a large diameter end. This large surface area can result in a more rapid change in temperature than the shaft, which is essentially a compact block of steel. In this case the bore of the hub can expand quicker than the shaft and the fit between the hub and shaft may be lost. Eventually the thicker component will “catch up” but damage can occur while the temperatures are stabilizing. Shaft looseness or movement of a bolted hub/backplate connection can result in a change in the wheel’s center of rotation. The resulting imbalance can cause damage to the bearings through increased vibration levels.

Rapid delta T events can be accommodated with good design. To combat hub/shaft movement, interference fits are used. To eliminate movement at the hub/backplate bolted connection fitted bolts are often used. There are many other ways to accommodate differing expansion rates in order to prevent either harmful stresses or mechanical looseness from developing. Suppliers have various preferences so it is worthwhile to discuss the options with a few.

In conclusion not only is it important to spell out what the equipment will experience, but in some cases, when it will experience it can be just as an important.

Neil Fraser, P.Eng.
Neil is a senior application engineer with CB Power and Industrial Equipment

Fan Selection and Application in the Cement and Lime Industry

Hormigonera, originally uploaded by Daquella manera.

Click the Slideshare link below for an informative and interesting powerpoint presentation on fan selections in the cement industry (albeit not as fancy-shmancy as this cement-mixing truck ;-))

The slideshow works in conjunct with a video presentation of the same topic (coming soon to an industrial b2b blog near you).

Fan Selection and Application in the Cement and Lime Industry

View SlideShare presentation or Upload your own. (tags: cement lime)

Ventilation – Design Considerations Part 1

This is the first in a series of articles about the design considerations of main and booster fan installations. The next two articles will cover general mine ventilation practices including equipment selection and installation, operation and maintenance.

An underground mine’s primary and booster fans are large pieces of equipment that are similar to the power that comes into your house – nary a thought is given to the work they do until they stop.

These fans consume the majority of a mine’s total electrical load as they operate 24 hours per day, seven days a week. They form the base load of a mine’s electrical system that cannot be shed during peak power situations. Because the cost of running these fans is high, it is important that the power consumed isused effectively in achieving the goal of delivering the correct ventilation amounts to the various work areas.

In terms of the fan selection, the flow component can be readily calculated. In Canada, provincial legislation mandates the proper dilution ratio. For example, Ontario speci.es that 0.06 m3/s must be supplied for each operating kW of diesel-powered equipment(~100 cfm/BHP) operating underground. Additional cooling is required for the really deep mines, where the rock temperature increases 2*C for every 250 metres (3*F per 1000 feet) vertical on average.

Cooling is usually based upon air velocities within the underground drifts or mine openings, although air-cooling plants can also be utilized. With regards to mine air cooling utilizing air velocities, the American Conference of Governmental Industrial Hygienists (ACGIH) have a number of heat/stress charts, based on the work activity, and Wet Bulb Globe temperature which will aid the ventilation engineers and designers in determining what additional air velocity and thereby air volume, is required.

The fan static pressure (FSP) component of the rating is determined from the flow requirements. The pressure loss is a function of the velocity through that section and the roughness of the wall. Knowing each section’s air volume .ow and using the cross-sectional area for that section, one can readily calculate the velocity of the air traveling through each mine section. Totaling up the losses of each section, one will arrive at the total pressure loss and the amount of FSP that the fan must deliver to move this volume of air.

A good rule of thumb for air velocity calculations is to keep it under 10 m/s (2000 fpm) for each section. The rationale is based not only on energy losses, but on safety issues as well. Where air-flow velocities exceed 10 m/s, an increase in medical incidents is usually reported, the most common being dust particles in the eye.

As pressure losses are a function of air velocity and wall roughness, anything that can reduce roughness should also be considered. Some mines have lined major air intakes (raises) with concrete – a costly but effective way to reduce pressure losses.

As a mine has many branches, often ‘booster’ fans are required to overcome shortcomings in the main ventilation fans. Generally they are used where additional fan static pressure is needed to overcome pressure drops in long or narrow sections of airway. Again, the same rules apply in selecting a booster fan as they do for the primary system.

Determining the flow and pressure are two main considerations to select a fan, but there are of course many more. Density of the air is also an important parameter. Air density can either be increased or decreased by the air temperature, the air/gas molecular weight, its humidity, the elevation in which the fan is operating and amount of suction the fan will experience. The topic of density is a topic in itself and we will return to that in another issue.

The main thing to know is that density has a real effect on the static pressure requirements and the horsepower consumed.

How to Reduce Material Waste

Reducing material waste means greater resource efficiency, less pollution and more profits. Each dollar saved on raw materials costs goes straight to the bottom line.

Raw material costs have edged up over the last few years and throughout 2008. The bloated costs today continue to pressure manufacturers of all sizes — a challenge that is unlikely to change anytime soon.

Prime Advantage, a buying consortium serving midsized manufacturers, recently found that an overwhelming 93 percent of respondents agree that raw materials (including stainless steel, nickel, copper and other metals and plastics) top the list of concerns for the second half of 2008.

While these findings are of little surprise, it is the significant and rapid change in perception that should be particularly revealing: In a Prime Advantage survey at the start of the year, 43 percent of respondents said they were apprehensive about the rising cost of raw materials. A mere six months later, those who say raw material costs will continue to be an economic concern for the remainder of 2008 jumped by 50 percent.

The data, collected from 72 senior-level representatives of industrial manufacturing companies, also determined that two-thirds of manufacturers (up 49.5 percentage points from the start of the year) agreed that energy costs are “a major concern” for the rest of the year. Identified as a concern by only 17.5 percent of respondents in early 2008, the new survey indicates that number has jumped to 67 percent.

“The current economic climate requires us to be wise spenders both as individuals and business people,” explains Elaine Sharp, program marketing manager of sustainable business resource Envirowise. “Achieving savings through better use of resources has a tangible effect on companies’ bottom lines and as a result we have often seen improved staff motivation and morale.”

Before you can eliminate raw material waste, you need to be able to identify it. To do this, every aspect of the production process should be addressed and tracked.

“The lifecycle flow of materials (e.g., end-use material efficiency improvement and cascading through reuse, recycling, and recovery) and their storage in the economy (stockpiling) are not well understood, and as a consequence, important options for efficiency improvements might be overlooked as attention is focused instead on energy efficiency in materials production,” recommends the Materials Research Society in an April 2008 paper.

“Issues such as raw material use, waste production, energy consumption and emissions to the atmosphere should be considered at each stage of the product lifecycle,” recommends the UK’s BusinessLink.gov, which offers practical advice for businesses.

To save the most money, businesses must take a strategic approach to minimizing materials waste. Consider focusing on at least these areas:

Inventory
Many companies over-order the amount of materials required to fulfill the order, especially in the make-to-order environment, says Envirowise (free registration required). In fact, according to the latest Manufacturing Index from the National Association of Manufacturers and IndustryWeek, “nationwide inventory-to-sales ratio for overall manufacturing reached a six-year high” in the third quarter of 2008.

The true cost of excess inventory levels should be analyzed carefully before a business orders excess raw materials. Just-in-time inventory and lean manufacturing can eliminate such unnecessary costs by matching production to demand in real time to eliminate the need for excessive inventory, warehouse and equipment space, etc.

“Check how you handle and store raw materials,” notes BusinessLink. “Even failing to empty all bags and containers properly could lead to significant amounts of waste.”

Reuse/Reprocess
“Reusing items is another way to stop waste at the source because it delays or avoids that item’s entry in the waste collection and disposal system,” the U.S. Environmental Protection Agency (EPA) recommends.

Envirowise offers this basic “wastebusting” example for the factory:

In most paint and chemical plants there is a plentiful supply of empty raw material drums to use for waste containers. But even in plants where this possibility for re-use is recognized you may still see new drums used for waste, usually for want of a system of supplying empty raw material drums to the areas that need them — the waste-generating departments.
“Look carefully at the waste you’re disposing of,” BusinessLink suggests. Could any of it be put back into the production process or reused for another purpose? Reuse turns materials that would otherwise become waste into valuable resources. Already, today’s products are being increasingly manufactured with total- or partial-recycled content, such as recovered plastic in carpeting and park benches.

Product Design
“Formulate for disposal or recycling,” Envirowise advises. “Avoiding the problem of obsolescence should start at the earliest possible stage — when formulating new products.”

“In tracking waste, you should understand how many good parts you’re getting to how many bad parts,” says private-equity firm Gaebler Ventures. “This could be applied to raw materials or finished products. If you’re constructing metal chairs and you have a good deal of scrapped steel, you should be aware of what percentage of your order is being utilized.”

Where possible, use materials that have already been recycled or can be reused, recycled or recovered.

One example of an area for improvement is packaging materials, from which a high proportion of waste comes. “Use the minimum packaging required for safety, hygiene and consumer acceptance,” recommends NetRegs.gov.uk, an environmental regulations advisor for small businesses. “When businesses manufacture their products with less packaging, they are buying less raw material,” notes the EPA. “A decrease in manufacturing costs can mean a larger profit margin, with savings that can be passed on to the consumer.”

Conclusion
“The bottom line is that pricing pressures for raw materials and commodities will likely continue to be an obstacle to success for many North American manufacturers,” Louise O’Sullivan, president and founder of Prime Advantage, said in a statement.

For manufacturers, using raw materials more efficiently can bring significant cost savings.

To prevent the waste of materials, continually assess systems and revise procedures and policies. Increasing the efficiency of industrial processes and the flow of materials through the economy is a slow transformation process that will take time.

“At all times, in all processes, waste can be reduced,” says Envirowise. “Where the payback seems poor, consider again whether all the costs have been taken into account and bear in mind that disposal costs, material costs and external pressures for improvement will continue to increase.”

“How to Reduce Material Waste” was written by By David R. Butcher and Licenced under a Creative Commons Attribution-Share Alike 3.0 United States License.

Heavy Duty Photo of the Week: Long Beach Oil Refinery 2

Long Beach Oil Refinery 2, originally uploaded by David Sommars – (thorhammer67).

Great night shot by David Sommars makes this the Heavy Duty Photo of the Week.

Fan Engineering Blastphemy

I had my Fan Engineering book on my desk today and a friend who has never seen one before commented that with its black bound cover and gold lettering it looks like a bible.

“Uh, I think that was the intent.”, I said. “In fact, it is called the Fan Engineering Bible” and a good companion for any person working with fans. (Robert Jorgensen did a nice job on that book).

Anyways my friend said, “Okay if there is bible then what would be fan engineering blasphemy be? Or, should I say blastphemy” in a mildly mocking tone.

Hmmm. Good question I thought from someone who is an English major.
Got me thinking.

So I want to list some of the mortal sins that a person may do that is so wrong that excommunication by AMCA is a real possibility — or at the very least — being publicly asked to step out of the buffet table line at a PowerGen hospitality suite.

Faux Pas No. 1

Thinking That Fans Decide What’s Going on

Fans are not that smart. They might be cute, but they’re not that smart.

When air isn’t moving as per the required amount all eyes generally go to the fan and the comment is said, “There’s something wrong with the fan.”

More often then not it is not the case. The system and its pressure drop “decides” what the flow of air will be. Poor duct design is often a major culprit to an underperforming fan/system.

When trying to figure out why a fan is underperforming look at the fan and its system. For instance look for sharp bends that create eddies and turbulent flow. Also look for abrupt increases and decreases in diameter. Look for high fan outlet velocities – typically over 4000 fpm — that lacks an evase that would help to “regain” some of the static pressure.

Or just ask your friendly neighborhood fan guy.

Faux Pas 2.

Thou Shall Not Exceed Tip Speed Limitations

Fans can be connected to a 30 hp or 3000 hp motor. Either way that is a lot of energy in a relatively small container. It is all safely contained as rotational energy. But here’s the thing … that kinetic energy can become a little bomb if the fan wheel stresses exceed its designed yield strength.

Speeding up a fan without checking what the maximum tip speed limitations is no joke.

Also if you are replacing a fan wheel please don’t go a ordinary fabrication shop.

Use an approved fan manufacturer who understands stresses inherent in fan wheel design. The static components are different then a wheel as they don’t see the same stresses.

Don’t take chances on a fan wheel.

Faux Pas No. 3

Thou Shall Not Run the Fan Backwards.

A centrifugal fan running backwards can still push air — except of course a whole lot less. If you have a problem and you are troubleshooting the first thing you check is rotation. I personally came across two main exhaust fans running backwards. Everyone naturally assumed the two fans couldn’t be running backwards. One perhaps, but two, no way. Except of course it was.

Reminds me of a scene in the movie Slingblade where they are trying to figure out why a gas mower won’t start. One of the characters (Scooter) said he can’t figure out why it won’t run. He changed the points and the sparkplug.

The Billy Bob Thornton character (Karl) squats down, unscrews the gas cap and says, “The gas tanks empty”.

Moral, check the simple things first and go from there.

Well I can write a whole lot more but these if three are abided by it will mean you will have a good chance of staying in the buffet line right up to the roast beef.

Jim Wywrot

Ventilation – Design Considerations Part 2

This is the second in a series of articles about the design considerations of main and booster fan installations. If you haven’t already, go ahead and read Ventilation – Design Considerations Part 1, written by Cam Seeber and Jim Wywrot.

In the last issue we talked about how volume and static pressure requirements for primary and booster fans are determined. The next step is to select the type of fan.

General guidelines that have been around in the industry will state that for a fan operating with a Static Pressure (SP) of 1.75kPa or less (<7¨ w.g.), an axial fan offers the best choice. One advantage of an axial is simplicity of overall design. At the higher end, where conditions dictate a fan to provide static pressures at 4.5 kPa (18¨ w.g.) or greater, a centrifugal is the obvious winner because of its ability to develop higher pressures. Over time axial fans have increased in size and capacity. Correspondingly their ability to deliver higher static pressures has also increased. However, in smaller fans, such as generally found in booster fans,these guidelines generally hold.

Regardless of which is used or at what range, selecting the fan is only half of the problem. The layout–both on the drawing board and on site–is really the ‘heavy-half’ of the design.

When a fan’s performance is measured in a test lab, it is under idealized conditions. The entrance to the fan will be preceded by a straight length of duct 10 times the diameter of the fan’s impeller diameter or a smooth inlet bell. This ensures that the air streamlines are as close to laminar as practical, leading to the optimum fan performance. However, in the field it is often the case that there isn’t sufficient room to incorporate these large straight sections of inlet, and compromises must be made. Generally the rule of thumb is that at least six diameters upstream be straight without any changes to diameter. The greater the deviation from the ideal conditions, the larger the losses will be.

The rules also apply to the fan discharge. Any abrupt change such as an elbow can have detrimental effects. For a centrifugal fan, selecting the discharge and rotation of the fan to eliminate additional bends is a good practice and relatively easy. Out fitting elbows with adequate turning vanes, or splitters, will help in maintaining an even velocity profile to reduce the turbulence that leads to increased static pressure losses.

In order to develop useful static pressure, a fan rotates and therefore expels the air at a much higher velocity than will eventually travel down the mineshaft. In some fan literature, Fan Total Pressure is quoted. Fan Total Pressure as its name implies is the summation of the fan’s Velocity and Static Pressure. In this energy system the velocity pressure is not useable energy and must be converted to static pressure. This can easily be accomplished by utilizing a discharge cone or evasé.

A well-designed evasé slows down the air in a uniform manner to keep the amount of turbulence generated to a minimum. By doing this the maximum amount of available energy can be reclaimed back into useable static pressure. On the other hand, with an abrupt transition, less of the available energy from the velocity pressure is converted into static pressure and the rest simply ends up as heat.

Consider the following example, which demonstrates the importance of the evasé in providing an energy-conserving solution to a mine operator.

A fan is operating at 165 m3/s at 5.0 kPa (350,000 cfm @ 20¨ w.g.) static pressure with no evasé. In this example the fan is discharging at 51 m/s (10,000 fpm) directly into a larger duct with a sudden expansion and the fan is drawing 1,328 kW (1,780 hp). If the same fan uses an evasé to reduce the discharge speed to 20.3 m/s (4000 fpm), this will result in a 0.92 kPa (3.7¨ w.g.) static pressure regain. With the evasé in place the fan would now draw 1,204 kW (1,616 hp) or a savings of 124 kW (166 hp). If energy costs are $0.08/kW-hr, the power cost savings that result are $92,000 annually.

Even for a well-selected fan with good inlet and outlet conditions, this does not guarantee that the goals the fan was selected for are being met. The fans deliver the output, but where it goes from there, as Paul Harvey might say, “is the rest of the story”.

Heavy Duty Photo of the Week: Paper Mill Plant

Paper Mill Plant , originally uploaded by cbpowerandindustrial.

A nice photo of an industrial paper mill plant in Ontario, Canada from Randy Wywrot

The Ps and Qs of T&Cs (Terms and Conditions)

With large projects after all the technical design is completed the commercial terms become important. That is the price, delivery and the terms of sale.

To the engineer Terms and Conditions might be “Just that boilerplate at the end of the contract.” And may therefore not appreciate what is at play or at stake here.

Terms of sale, Terms and Conditions or T&Cs are in place to do a number of things not the least being setting out what warranties apply and what requirements may exist for canceling a contract or for issues around obligations for such things as delivery. They also protect or mitigate the extent of a lawsuit by an owner or user.

Most people are familiar with terms and conditions. Anytime you download the latest software or upgrade for a program like Adobe Acrobat the one thing you must do before any transfer can happen is one must accept the software’s licensing agreements, or T&Cs. If they aren’t accepted you don’t get the download.

With software, the delivery is in seconds or minutes. With the time between placing an order and delivery of some major equipment being weeks, months and even years the chances of a costly problem for the both the supplier and the buyer increase.

To manage and control the risk of an unforeseen event the supplier will want their terms of conditions, while the purchaser will want theirs.

Most companies will have standard terms and conditions and these are attached to equipment proposals. For equipment parts sales or in large projects of complete components such as pumps there will be an acceptance by one party for the others; or some accommodation forming a new agreement of sale – as the legal people look at what is proposed for the T&Cs and what they can live with.

Often (okay in most cases) the language may seem baffling. Worse is when the language to an untrained eye seems innocuous but can have other more far reaching meaning should a disagreement land in court.

These pre-loaded words come from precedents and the like. Citing a favourite tool – Wikipedia — “Common refers to law and the corresponding legal system developed through decisions of courts and similar tribunals…”. What this means is courts will often refer to precedents that are set in an earlier case to help adjudicate the one before them. If a precedent was established using a definitive word or combination, those words then can take on a meaning that neither party may not have intended or fully understood.

For instance time is of the essence in a contract document may seem like a pretty straightforward comment that you might hear in the street. However innocuous it might sound it has far reaching implications in terms of how job might be executed in a supplier’s manufacturing plant. The web site www.legal-explanations.com say of this phrase “It is a statement used in contract or agreements and meant to specify that the time and dates mentioned in contract are very important to maintain and should not be ignored by any of the party under any circumstances. The agreement is liable for cancellation if there is a delay of any form.”

In other words it has the capacity to be a very serious clause with far reaching implications.

These sorts of phrases can be buried into T&Cs as part of the standard template but can have serious repercussions. Therefore savvy suppliers when they see this phrase and others will ask for the clause to be removed or will substitute with some alternate wording that doesn’t expose the supplier to something as drastic and unintended.

Warranties are another large part of terms of sale. Within the warranty language one might find the word Merchantability, or Implied Warranty of Merchantability built in. It is another one of those words that can have a meaning unseen to a non-trained eye and has to do with using a product in a nonstandard way.

For anyone who is interested in this specific definition I invite him or her to the following link http://legal-dictionary.thefreedictionary.com/merchantability, which explains this is greater detail.

As engineers, buyers and users of equipment Terms and Conditions are something we become aware of. They are important and need to be given the proper respect.

Northern Mine

Northern Mine, originally uploaded by cbpowerandindustrial.

Looking at this photo, I can almost feel the cold northern Ontario air… and the frostbite.