NH3 in industrial refrigeration: leading American end-users talk safety

By Silvia Scaldaferri, Jun 24, 2013, 17:01 4 minute reading

Representatives from some of the leading U.S. brands, including Tyson Foods Inc., Campbell Soup Company, ConAgra Foods and Port Newark Refrigerated Warehouse, shared their NH3 experiences with the 200 participants at the 2nd annual ATMOsphere America 2013 conference in Washington DC. Employee safety and training were the focal points of the discussion.

Eric Smith, Technical Director at the International Institute of Ammonia Refrigeration (IIAR), opened the Industrial End-User Panel with a brief introduction to his organisation the IIAR which provides advocacy, education, standards and information for the benefit of the ammonia refrigeration industry. Emphasising the importance of the IIAR as an ANSI accredited standards writer, Eric Smith stated: “If we do not develop our standards, someone else will” and “OSHA would use our guidance if it was complete.” When standards are accepted by Code Bodies, they are given more “heft” and are, consequently, more likely to be adhered to.

Preparedness is key

Michael Chapman, Manager of Process Safety and Risk Management Programs at Tyson Foods Inc., explained that most of Tyson’s 100+ facilities employ anhydrous ammonia because it is economical, efficient and natural. “[Ammonia] can be managed safely but it requires preparedness, as does using any other refrigerant. Preparedness is a combination of education and maintenance.”

According to Chapman, employee safety is the Tyson’s number one concern. Costs due to injuries (most of which relate to technicians operating the systems), litigation and workers compensation, as well as penalties from citations for not appropriately managing systems, all affect profitability. Therefore, Chapman emphasised the need to know the systems, the emergency responders and to make a plan. There must be a team that is trained to react in the first crucial ten minutes and this team must have someone taking charge – an incident commander. “It’s all about crisis management, having someone on the ground who can take responsibility” Chapman said. The quicker the crisis can be addressed and damage minimised, the less business is interrupted and the fewer profits are lost.

Minimising safety concerns in bakeries

The Campbell Soup Company, which produces famous brands such as Prego, Pepperidge Farm, V8 and Pace, employs ammonia refrigeration in several of its manufacturing facilities including thermal processing, bakeries and vegetable processing. The benefits of ammonia are energy and maintenance savings and that it avoids the potential future need to convert systems, the cons are safety and investment cost says Robert Czarnecki, Program Manager for Refrigeration at Campbell Soup Company. Yet safety concerns can be minimised through design, training and low charge.

While thermal and vegetable plants predominantly use NH3, most of Campbell’s bakeries are still R22 (95%) (unitary equipment) with some ammonia. Since 2010, Campbell’s has begun an R-22 conversion program for its bakeries using NH3/glycol. 7 bakeries are planned to be converted. The impetus for making this change was the Montreal Protocol and energy and maintenance considerations, among other things. One of the main obstacles has been that bakeries do not have the same comfort level with ammonia because they have very little experience with it. So far, 4 bakeries have already been converted; the remaining 3 facilities will be converted over the next 4 years.

NH3 – as safe as any other refrigerant

Eric Johnston, Principal Engineer from ConAgra Foods Inc., one of the largest food companies in North America, explained the company’s experience using ammonia refrigeration. ConAgra Foods produces recognised brands such as Chef Boyardee®, Egg Beaters®, Healthy Choice®, PAM®, Slim Jim®, Snack Pack®, etc. The company also has a strong commercial foods presence, supplying products to well-known restaurants, food services operators and commercial customers.

Out of ConAgra’s 38 plants with significant refrigeration systems, 27 use anhydrous ammonia as the primary refrigerant. These systems range in size from 1,400 lbs to 283,000 lbs (635 kg to 128,366 kg) to of anhydrous NH3. For all facilities using NH3, ConAgra has implemented a comprehensive performance based written Process Safety Management (PSM) and Risk Management (RMP) program. No matter the size of the system or operating charge of the system, the company maintains that any facility using ammonia must have a full PSM and RMP programme implemented. The Corporate Engineering staff, which supports these programmes, is responsible for conducting audits/inspections, programme training, project reviews, project start-ups, incident investigation/assistance, etc. According to Johnston “our history has shown that through the proper handling, operation, and maintaining of our Ammonia Refrigeration systems, they can be just as safe as any other refrigerant system.”

Ammonia – the best refrigerant in the industry

Gerard Von Dohlen, CEO of Port Newark Refrigerated Warehouse, the largest apple juice concentrate storer in the US, says that it has been known for over 100 years that ammonia is the best refrigerant in the industry. Unfortunately, in New Jersey, the “freon capital of the world,” the government has all but banned the use of ammonia by requiring a 24 hour-a-day operating engineer to be on hand, which costs approximately $600,000 per year (450,550 EUR).

According to Von Dohlen, there is no doubt that ammonia is a better choice than R22, which leaks at a rate of about 30% a year. He says it is impossible to operate an R22 system economically at $23/pound (18 EURO/.5 kilo), and switching to R507 is not a solution. Von Dohlen is also not convinced of the efficiency of CO2 refrigeration compressors. He says that AC systems using ammonia chillers in a typical centrifugal chiller are the way forward and can reduce the operating charge from 20,000lbs to 2,000lbs (9070 kilo to 907 kilo). “If you design it right, operate it right and manage it safely, it is a good refrigerant” Von Dohlen says of NH3.


By Silvia Scaldaferri

Jun 24, 2013, 17:01

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