- THE MAGAZINE
- FOOD MASTER
Known for their heavy use of energy, the meat and poultry industries need to cut usage wherever they can.
Suppose you do an energy audit at your further-processing plant that manufactures luncheon meats, hot dogs, bacon and sausages. The audit finds:
- You could reduce natural gas consumption by 20 percent, with potential savings of $270,000 per year and an overall payback in less than one year;
- You could reduce electrical consumption with potential savings of $400,000 per year with an overall ROI in three years;
- You could install an onsite cogen system with potential savings of $1.4 million per year;
- You could save $40,000 per year simply by reducing steam pressure from 125psig to 100psig; and;
- You could save $30,000 per year with no capital investment by increasing the suction pressure in your refrigeration system from 15 to 18psig in your flooded system and from 15 to 24psig in your dry system.
While you wouldn’t be likely to take on all these projects at once, you’d certainly look at the ones that cost you little or nothing. The numbers above came from an energy study performed at Schneider Foods of Kitchener, ON. The study, Energy Savings in Meat Processing, was published by the Ontario Centre for Environmental Technology Advancement and the Ontario Ministry of Agriculture and Food. When the report was published, Schneider Foods immediately took advantage of the adjustment to the suction pressure on its refrigeration system to the tune of $30,000 per year.
So far, we haven’t even talked about some more obvious energy wasters in your facility—for example, excess water usage, leaking air lines, uninsulated building shells, etc. Why would you want to do an energy audit? Why would you want to take action? While it might be good for your public “green” image, it also can help your bottom line—in effect, making you more competitive.
An energy audit establishes the baseline for identification of steps that a processor can take to monitor and implement modifications/controls, says Darryl Wernimont, director, POWER Engineers. “Remember, this should be considered an ongoing process, reviewing and challenging [the audit] on an annual basis. Bring the team back in, review what you’ve accomplished and look for optimization and new ideas going forward. Establish a goal.”
And “green” is probably not going away. “Meat and poultry manufacturers should step back and review what has occurred in the past ten years,” adds Wernimont. Processors should examine how market and consumer expectations have changed, and they should challenge their team with the following question, says Wernimont. “If the next ten years see as much activity as we have seen in the past ten years, can we afford not to embrace new energy and environmental issues?”
A more energy-efficient production process allows a manufacturer to have a lower operating cost. “Processors should take energy efficiency seriously because their competitors are always looking for ways to produce more product with less input,” warns Steve Radke, JBT FoodTech sales manager, eastern region.
“In my opinion, energy efficiency—or maybe more appropriately—energy cost should absolutely be considered a strategic competitive issue,” says Robert P. Sabin, Emerson Process Management consulting engineer. “It is a significant component of the cost of goods sold and possibly the largest component of cost that can be affected by direct site actions.” Raw material, labor and many other costs are either relatively fixed or driven by outside factors, whereas energy can be influenced through site efforts—or the lack thereof, adds Sabin.
“Critical to gathering insight into whether ‘I am good’ or ‘I am efficient’ is the ability to normalize consumption to production values,” says Gary Kohrt, Iconics vice president of marketing. Analytical software to monitor energy usage can integrate all data from plant control systems and business systems to create visualization and real-time analysis of relationships between variables. Examples include trend views that show total electrical consumption per pound produced or charts of the total accumulated steam used per thousand pounds of production, says Kohrt.
Why build an onsite digester and CHP?
Additional benefits of an onsite digester with energy recovery include:
“Any tool or solution that reduces overall expenses should be evaluated as a possible strategic advantage for the user,” says Joe Bove, Stellar vice president. “The processor calculates the price point for its products based on all costs necessary to manufacture the product plus its margin.” These costs include—but are not limited to—labor, materials and expenses. Power and utility costs factor immensely when calculating the unit cost for manufactured goods and services. Processors take these costs very seriously to the extent where return on investment (ROI) may hinge directly upon measurable energy reduction. However, more efficient solutions tend to cost more than less efficient solutions. Therefore, project budgets versus long-term savings must be compared and valued against each other, according to Bove.
Energy-saving solutions should be well planned and not attempted all at once because they can be disruptive. “Some companies have seen that isolated capital investments in ‘green’ solutions can actually disrupt stable processes that currently manufacture products relatively efficiently,” says Katie Beissel, GE Intelligent Platforms global industry manager—food and beverage. “Concurrently, some processes can actually result in waste, whereby simply improving efficiency and yield would deliver more benefits than a major capital investment in ‘green power’ or water conservation.”
Waste not, want not
Recent US energy flow trends indicated overall energy losses at approximately 55 percent versus useful energy in the range of 40 percent. “We have begun to see similar carry-over to plant operations with energy wasted in the 50 to 55 percent area and useful energy being identified in the 40 to 45 percent range,” says Wernimont. Thus, there is always room for improvement.
“Typically speaking, in both meat and poultry processing facilities, refrigeration usage represents approximately 50 percent of the total electric energy spend,” says Alex Daneman, Hench Control Inc. CEO and president. Making energy efficiency a priority only makes sense from a financial and business standpoint. Anytime a business is able to increase its profit margins by taking a specific action, it should be viewed as a strategic, competitive act. However, Daneman points out long-term thinking is what’s needed—not throwing money at an immediate problem.
Daneman sees common problems in meat and poultry plants—using too many compressors to maintain the refrigeration system and machines that operate at higher horsepower ratings than needed. Load and demand in both meat and poultry processing plants vary constantly due to shift requirements, weather, season, etc. Because the operation is always in a dynamic state, having a fixed sequence or static group of machines operating the plant is not as efficient as controlling the units, running only as many at the speed needed to meet the cooling demands of the facility.
The audit of Schneider Foods magnifies the compressor problem. The plant’s total energy costs are about $4 million, with the largest energy consumers being the ammonia refrigeration system and steam systems. Refrigeration is supplied by a multi-compressor system, composed of 10 compressors in a dry system with 3,200hp capacity, and four compressors in a flooded system with 2,800hp. Besides the freebie of adjusting suction pressure, the study recommended the installation of new energy-efficient screw compressors, upgrading and replacing various condensers, and reducing ventilation rates.
“In meat and poultry processing, the building itself serves as a means to facilitate the [audit] process,” says Jim Oko, Stellar director of process engineering/food and beverage. “Typically, there is a greater chance for waste on the building side, which includes building envelope, refrigeration, water heating and lighting.” Oko says there are many places for waste, whether in the process or infrastructure, and power can be wasted simply through mechanical leaks in systems such as air and steam. Air leaks require compressors to run more frequently and/or at higher loading.
“One often overlooked fact is that the most expensive component in the total cost of compressed air production is energy,” says Paul Humphreys, Atlas Copco vice president of communications and branding. “Over the lifespan of a compressor, energy typically costs several times more than the purchase price of the compressor.” For example, a manufacturer running a 200hp air compressor 24 hours a day at 8 cents per kWh is likely to pay $110,062 to operate that compressor every year, or more than $550,000 over five years. Those costs are substantial and are likely a minimum of three times the purchase price per annum, yet they can be significantly reduced, according to Humphreys.
Humphreys also says a 1/4-in. air leak at 100psi with the same electrical rate of 8¢ per kWh will cost about $12,800 a year. Consider that compressed air systems, particularly older ones, can leak on average about 25 percent of all the air that is pushed through them.
A steamy issue
“Larger steam systems benefit greatly from an energy audit,” says Matt Asplund, Heat and Control engineering manager. “Larger systems can often increase their efficiency by using a more complex generation cycle. Condensate return and pre-heat, feedwater pre-heat and combustion air pre-heat all complicate the process a bit, but reduce the cost per pound of steam.”
In the Schneider Foods example, steam accounted for a total of five energy-efficiency opportunities, four of which cost little to do: reduce steam pressure, $0; improve turndown ratio, $0; eliminate warm standby boiler, $4,000; and reduce deaerator exhaust, $0. Reducing excess oxygen from 5 to 2 percent would have cost $100,000 and taken 7.7 years for payback.
“A simple improvement to a steam system that can deliver large financial return is to monitor larger and key steam traps continuously for malfunction,” says Emerson’s Sabin. Wireless, acoustic steam trap monitors can be bolted on or near the trap, and they provide a means to eliminate the largest source of loss in a steam system.
Boiler turndown and the coordination of multiple boilers to ensure best efficiency across the utility area are also subjects for action. Many sites vent steam excessively to manage header pressure. “This is wasteful, and when the overall utility operation is properly controlled and managed, unnecessary,” adds Sabin.
Processors should look at the cost of steam produced. Many times, combustion performance in the boilers is not ideal. Mechanical (jack shaft) arrangements may be in use for fuel-to-air control, or fuel-to-air curves may have been implemented in a controller. For best results, Sabin recommends combustion control should be done on a stoichiometric basis to deliver ideal efficiency at all loads and all ambient and fuel conditions.
Steam generation is costly because most boilers are not tuned to their peak performance, says Beissel. She has employed the GE Steam Cycle solution at some locations, and the system allows tuning the boilers continuously based on real-time operating parameters. Some processors have seen gains upwards of 15 percent in increased boiler operation efficiencies.
When it comes to saving electricity, most people think of using premium-efficient motors and substituting incandescent or fluorescent lighting with LEDs. Besides these, Radke notes processing equipment can be designed to use less energy by reducing the size and footprint of the equipment and using improved lubrication systems. In addition, modern process equipment is designed to be cleaned with less water and fewer chemicals and use a fully programmable CIP system.
“Our customers typically save 15 to 30 percent of electrical energy from their refrigeration system by taking advantage of our energy-saving techniques, including raising the suction pressure and lowering the discharge pressure whenever possible,” says Daneman. In addition, support technicians from Hench Controls are able to monitor processors’ systems and fine-tune them as necessary.
Sometimes it’s not so easy to save electricity on a particular air compressor, but there’s no reason the heat generated by the unit can’t be reclaimed. “Even within the most efficient compressed air systems, a fraction of the energy input, about 10 to 15 percent, is delivered as compressed air energy—most of the input electrical energy is converted into heat,” says Humphreys. There are two typical ways to reuse this energy, depending on whether the processor has an air-cooled or water-cooled machine—through hot air or heated water at up to 194°F. “The compressor now becomes the alternative energy source for scalding, cleaning, sterilization, heating and melting applications critical in these facilities,” adds Humphreys.
Beissel recounts a not-so-obvious, real-world electrical energy savings story. A meat and sausage producer had pieces of equipment operating independently of one another as standalone solutions, and the machines were equipped with a wide range of PLC controllers. These were being used for the individual production stages. To optimize the manufacturing processes and facilitate the required regulatory traceability, the standalone solutions had to be gradually changed over to a complete, networked automated solution. In doing so, the goal was not only to link together the individual system components at the field level, but also to create, for example, the requirements for vertical integration into the ERP system. As a result of the GE solutions, the customer can now operate a practical energy management system and monitor the central building control system. The processor also is able to realize lower energy costs through integrated monitoring and control.
Many processors are demanding equipment that consumes less energy. One simple method, says Asplund, is to insulate equipment and piping. Beyond this, equipment should be designed for cleaning with features like sloped, self-draining surfaces; drip and crumb trays designed to be easily cleaned; and CIP systems that reuse as much water and heat as possible. Smart sanitation systems for spiral ovens can be programmed for different cleaning cycles in each area of the oven to reduce the usage of heat, water and sanitation chemicals. Ovens with water-cooled pan bottoms prevent the burning of drippings, making them easier to clean. CIP sprays to reach hard-to-clean areas also reduce utility and energy costs.
Reducing the amount of ammonia in a meat or poultry plant’s refrigeration system can add up to savings as well, says JBT FoodTech’s Radke. In some cases, spiral freezers can be retrofitted with surge vessels that connect directly to the evaporator coil inside the freezer enclosure, e.g., JBT FoodTech’s Low Volume System (LVS) refrigeration, which allows a dry suction return to the engine room and can reduce ammonia volume by half.
Fryer oil filtration systems have gained attention recently as the price of oil has increased, says Radke, and processors in meat, poultry and other industries are experimenting with different oil filtration methods. One new technology is a continuous hot-oil centrifuge. Continuous filtration allows a hotter return oil temperature (energy savings), and the centrifuge technology can filter out particle sizes down to 1 micron, extending oil life.
Meat and poultry processing plants—especially slaughterhouses—create a lot of wastewater with high biological oxygen demand (BOD). Two questions arise as most public water treatment facilities are not equipped to deal with the high BOD levels emanating from these plants. First, should the plant process or pre-process its wastewater on site—as may be required by the municipal treatment plant—or should it incur the higher fees the municipality will charge if, indeed, the municipality treatment plant will accept untreated wastewater? The second question, is: When does it make sense to not only treat the wastewater, but also use a bio-digester to create gas for processing or to run a cogen system?
Is pre-processing a good idea? According to Stellar’s Oko, an operational and capital cost analysis would need to be compared to outside service as well as impact fees and surcharges. The decision would also depend on the quality, quantity and type of wastewater stream produced at a particular plant. For example, a plant utilizing large quantities of methane may choose to collect the waste and utilize byproducts to power other equipment or eliminate odor.
There can be significant benefit to the reuse of treated water onsite, but it is entirely dependent on the site constraints including: the cost of service (raw water and sewer), reuse options available (cooling water, etc.) and footprint available onsite. The technology required to achieve water of quality sufficient for effective reuse is typically additive to the normal treatment process and can be more complex than typical primary and secondary treatment options. With membrane-based treatment systems, however, it can be cost effective even for smaller plants, especially with high water and sewer costs, says Oko.
Many public treatment systems also have a fat, oil and grease (FOG) program, which in most cases, restricts meat processing fat from entering their system because it can cause serious plugged sewer problems, says GE’s Beissel. So processors may not have a choice but to pre-treat their water if it has high FOG content. If they pre-treat it to a tertiary standard—not potable—they could reuse it in their operations in many places such as toilets, ground water, etc., says Beissel. This could reduce the potable water purchase, but would need to be justified with a cost-benefit analysis before starting such a project.
Cogen in the cards?
With regard to the second question above, creating an onsite combined heat and power (CHP) plant that can supply both electricity and heat to the food processing plant is more practical from an economic standpoint. A CHP plant can consist of a steam turbine operated together with a boiler or a gas turbine with a heat recovery steam generator. A comprehensive paper by Anna Fritzon and Thore Berntsson, entitled “Energy efficiency in the slaughter and meat processing industry—opportunities for improvements in future energy markets,” includes several examples and “what-ifs.” The paper is available on the Food Processing Environmental Assistance Center’s (Purdue University) website (www.fpeac.org) under Meat/energy.
“The large volumes of process water of this type of plant, however, can necessitate a large footprint to achieve treatment and energy recovery objectives,” says Oko. Process wastewater from meat and poultry processing does lend itself to very effective primary treatment, which makes it practical to concentrate on the energy value of the waste and efficient and effective treatment in digesters—onsite or off, adds Oko.
“If a requirement/determination is made to treat facility-generated wastewater onsite, then treating the wastewater anaerobically can be a beneficial decision,” says David McCallum, GE Gas Engines-NA sales manager. “The byproduct of anaerobic treatment, i.e., methane gas, can serve as a fuel for a prime mover that can in turn produce electricity and heat for the plant. When a facility has the need for a thermal requirement, a CHP site can be invaluable. A facility can further reduce its energy costs by producing energy from digester gas and offsetting its electricity costs. In addition, using the heat from an engine to add heat to boilers, produce hot water or operate chillers can further reduce the energy costs for a facility,” says McCallum.
USDA meat plant reduces water treatment costs
A USDA-regulated meat packing plant in California had issues with its water treatment supplier that was running the plant’s evaporative condensers at less than three cycles of concentration while overfeeding treatment chemicals. These actions drove up the plant’s costs for chemicals and excessive water usage and discharge. In an effort to contain costs, the plant’s operators tried a non-chemical water treatment device on one of the three evaporative condensers, with near-disastrous results.
The plant asked Garratt-Callahan to provide an alternative solution. The supplier’s field representative implemented a new water treatment program on two of the evaporative condensers, installing dual biocide timers and equipment to control pH and conductivity. In addition, cycles of concentration were boosted to 4.5. He also monitored the performance of the third condenser’s non-chemical treatment. The results were poor, with significant scaling. After one year, the test was terminated in favor of the Garratt-Callahan treatment already underway on the other two condensers.
In two years, the solution saved the plant operators $9,800, including $5,000 in reduced chemical costs and $4,800 in reduced water and sewer costs. Even adding back the cost of the sulfuric acid for pH control, the plant’s water treatment costs have been reduced by a net $7,000. The new program has proven more effective than either the prior program or the non-chemical equipment.
Source: Garratt-Callahan, www.g-c.com.
For more information:
Alex Daneman, Hench Control, Inc., 510-741-8100, email@example.com
Steve Radke, JBT FoodTech, 419-626-0304, firstname.lastname@example.org
Robert P. Sabin, Emerson Process Management, 512-835-2190, email@example.com
Joe Bove, Stellar, 904-260-2900, firstname.lastname@example.org
Paul Humphreys, Atlas Copco, 866-546-3588, email@example.com
Gary Kohrt, Iconics, 508-216-1238, firstname.lastname@example.org
Jim Oko, Stellar, 904-260-2900, email@example.com
Matt Asplund, Heat and Control, 510-259-0500, firstname.lastname@example.org
Katie Beissel, GE Intelligent Platforms, 800-433-2682, email@example.com
David McCallum, GE Gas Engines-NA, 360-693-0117, firstname.lastname@example.org
Darryl Wernimont, POWER Engineers, 904-318-7186, email@example.com