Killingly Cogeneration Plant
Frito-Lay North America, Inc.
(A business unit of PepsiCo, Inc.)
Pacesetting Plants • Class of 2008-09
Combined Cycle Journal
Second Quarter 2009
When C.E. Doolin and Herman W. Lay merged their companies in 1961, they really couldn’t have imagined that within 50 years Frito-Lay brands would account for 59 percent of U.S. snack-chip sales and that the company would have 36 production facilities and nearly 50,000 employees in Canada and America.
You don’t achieve that level of dominance in any industry unless you really know what you’re doing – from A to Z. The food industry is not energy intensive as chemicals, refining, electric power production and primary metals are, but it’s not far behind. Some sectors of the industry consume more energy per pound of product than others. For example, making chips requires a significant amount of electricity and a lot of thermal energy to heat the oil that cooks the potato and corn chips.
Thus the better job the company does managing energy consumption, the more competitive it can be on the grocery-store shelf. This certainly is not news to the people at Frito-Lay. They have had an aggressive resource conservation strategy in place for a decade – in line with parent PepsiCo’s commitment to minimize the impact of its business on the environment through energy management.
Performance with a purpose is the corporate philosophy. All Frito-Lay business-unit leaders are challenged to do better by doing better. No, Yogi Berra did not say that. No, it’s not a “gimmick.” No, it’s not just more “corporate speak.” This is serious business; Frito-Lay’s employees “walk the walk.”
Al Halvorsen, director of environmental sustainability, said during a conference call with Combined Cycle Journal editors and Frito-Lay’s principal engineer Kevin Chilcoat and project engineer Ray Riley that the company made a commitment in 1999 to reduce its environmental footprint. Goals were to reduce water use by 50 percent, electric consumption by 25 percent, and natural-gas consumption by 30 percent within 10 years. Challenging goals considering no one really knew what was achievable.
This was not a headquarters mandate being “pushed out to the field” to see what might happen. Working towards the goals would be a team effort involving the HQ central engineering group in Plano, Texas, and the energy manager at each production facility.
Success, Halvorsen continued, hinges on people, processes, procedures and technologies. People are the key, and they are empowered to identify wasteful practices, present their suggestions on how to improve, help develop a viable solution, and then participate in the implementation of that solution. The formula was correct. Results of the first 10-year plan are impressive: Reduced water consumption by nearly 40 percent, reduced electricity use by 22 percent, and beat the gas goal.
Frito-Lay knew its people had many of the ideas needed to reduce the company’s energy and water consumption and emissions – but not all of them. The snack-food manufacturer joined EPA’s ENERGY STAR program in 2004 to take advantage of others’ experiences and to network. The value of networking cannot be overstated, as the various gas-turbine user groups prove to Combined Cycle Journal subscribers at every meeting.
ENERGY STAR was introduced by EPA in 1992 as a voluntary market-based partnership to reduce greenhouse gas emissions through increased energy efficiency. The program grew to more than 9,000 partner organizations committed to improving the energy efficiency of products, homes and businesses (www.energystar.gov).
Halvorsen said ENERGY STAR helps facilitate a food-industry energy alliance, enabling all producers and processors to share best practices. Environmental sustainability depends on all companies playing a positive role, he added, not just one or two. Frito-Lay drove participation in ENERGY STAR within PepsiCo, serving as a role model for the conglomerate’s other companies. PepsiCo itself joined in 2006.
That PepsiCo is “committed” is reflected by its Research Conservation Outreach Program. The company provides tools and expertise to business partners, encouraging them to implement energy management practices provided by ENERGY STAR. The company received the program’s Energy Management Partner of the Year Award in 2007 (Frito-Lay was recognized similarly in 2006) and was presented awards for Sustained Excellence in 2008 and 2009.
PepsiCo also is an active participant in EPA’s Climate Leaders Program and Green Power Partnership. The company is a national leader among green-power purchasers. To give you a better idea of how important environmental sustainability is to PepsiCo, look where the company is headed: Retrofit of its plant in Casa Grande, Ariz., will make it the company’s first facility to run almost entirely on renewable energy and recycled water.
CHP Fits at Killingly
The background on Frito-Lay and parent PepsiCo was important to help understand the thoroughness with which the company approaches its energy projects. All must meet strict payback, performance, production-enhancement, and environmental-improvement criteria. Nothing is taken for granted; all decisions are verified and re-verified.
Dana Technologies, Inc., in San Juan Capistrano, Calif., serves as Frito-Lay’s owner’s engineer on many energy projects. President Jim Leach, PE, told Combined Cycle Journalthat the manufacturer is very conservative technically and that Dana and Frito-Lay share decision-making regarding system/equipment specifications and selection. Both organizations agree on how to proceed or they go back to the drawing board.
Bob Fitzsimmons is facility manager at Killingly in the northeast corner of Connecticut. The plant ranks fifth in production capability among the 36 Frito-Lay facilities. When Fitzsimmons showed Combined Cycle Jounal his plant, the CHP facility was being commissioned.
CHP was a natural here, for several reasons:
- A fourth boiler was needed at the plant. Two of the three original gas/resid-fired packaged boilers, each rated 40,000 lb/hr of 325-psig saturated steam when new 30 years ago, barely cover the typical peak winter steam requirement (process and heating) of 75,000 lb/hr. Steam heats the oil used for frying chips in a shell-and-tube heat exchanger, and heat exhausted by the fryers is captured and used for space heating.
- Facility has a peak electric load of 3.6 MW and depends exclusively on mechanical refrigeration.
- The Connecticut grid has its weak spots. At the time Frito-Lay was evaluating its energy options at Killingly, the state was offering grants for CHP systems to help reduce grid congestion; Frito-Lay’s proposal was accepted. Another benefit of the grant program: No backup-power charges if the GT is forced out of service.
Halvorsen’s headquarters team knows that while CHP “sounds good,” it doesn’t fit in every location. Snack-chip production, electric rates and congestion charges, regulatory environment, and balance between electric and thermal demand are all parts of the equation. In fact, Killingly is only the company’s third CHP project. The first, in Kern, Calif., is still in operation. The second, also in California, was sold when the manufacturing plant it served shut down.
Frito-Lay weighed all the options. It considered (1) reciprocating engines, but they didn’t produce sufficient heat for process use; (2) fuel cells, but they were expensive compared to gas turbines; (3) power export to the grid, but that was not economically justifiable; (4) various GT models, including Solar Turbines, Inc.’s (San Diego) high-efficiency Mercury™ 50, but its thermal and electrical output didn’t match what Killingly needed.
Frito-Lay brought together its “A” team for the Killingly project – a mix of both inside and outside talent. Chilcoat and Riley were among the “insiders.” The “outsiders” included Dana Technologies’ Leach; Marc Letourneau, PE, project engineer for Waldron Engineering & Construction Inc., Exeter, N.H., the EPC contractor; and Luke Conner, president of CPL Systems, Inc., Lafayette, La., the controls integrator. Only Waldron hadn’t worked for Frito-Lay previously, but it brought a solid resume to the project.
The two major components of Killingly’s gas-only CHP system are a Solar Centaur 50 gas turbine and a supplementary-fired heat-recovery steam-generator (HRSG) from Rentech Boiler Systems, Inc., of Abilene, Texas. The Centaur 50 is very similar to the Centaur 40 selected by Smith College for its CHP system. It also has an 11-stage axial compressor and three turbine stages. But the 50 has 12 fuel injectors, two more than the 40; plus, it produces 4.6 MW, 1.1 MW more than the Smith unit. Heat rates are comparable.
Leach said the Solar turbine was right-sized for the application. For him, there were no serious alternatives. The controls design and package met requirements, and the industry had good experience with the engines. Dana Tech, he continued, wrote a specification around the specific features the team wanted in the engine package.
The HRSG produces up to 60,000 lb/hr at peak firing capability (figures 1, 2). The GT’s SoLoNOx dry, low-emissions combustion system, together with the SCR incorporated into the HRSG, limit NOx emissions to 2.5 ppm. Permitted ammonia slip is 12 ppm.
Leach told Combined Cycle Journal that Frito-Lay has a short list of vendors it is comfortable working with, just as with a typical electric utility. Rentech is on that list. Its HRSG offering was selected on design features such as installing the duct burner in a waterwall firebox of an O-type boiler to reduce overall length.
Waldron’s Letourneau said the contractor shared much of the same thinking as Frito-Lay. It stressed system simplicity for optimum reliability and ease of operation, specified and purchased equipment with proven track records in similar service, and assembled a top-notch construction team with known and proven subcontractors.
One of the ways Frito-Lay and its contractors preserved simplicity is illustrated by the gas-supply option that they selected. There were two ways to go: Tie into a nearby line that would have required a booster compressor or run a long pipe to a higher-pressure line. The latter was selected to avoid possible reliability issues associated with gas compressors.
Given the state’s weak grid, Frito-Lay wanted the capability to run in the island mode. The company never wants to be forced to shut down its production operation. Two days after testing relays during commissioning to verify isolation, a squirrel shorted out local service. The entire area – except Frito-Lay’s plant – was blacked out for about a day.
Halvorsen and his team took the opportunity to upgrade the condensate/feedwater system while the CHP system was installed. High-pressure (175-200 psig) condensate returns from the shell-and-tube cooking-oil heaters flow to a new HP condensate tank. There a portion of the returns flash to feed the plant’s 90-psig steam header.
Low-pressure condensate returns flow to the deaerator, which supplies water to the HP condensate tank to maintain the optimum level. Redundant boiler-feed pumps with variable-speed drives take suction from the condensate tank and pump its 310F-325F water to the HRSG’s economizer.
CPL Systems’ Conner has been in the controls business more than three decades, but if you’re not located in the Gulf Coast area you may not know the firm. It was in Killingly for a job because it understands the Frito-Lay snack-chip manufacturing process well and does a lot of work for the company. Conner also has considerable experience with Solar turbines. One of the firm’s claimed core competencies is optimization of economics, emissions and other variables.
Chip frying, Conner said, is a continuous batch process. Shut down a line and steam flow drops by 40 percent almost instantaneously. One of the challenges at Killingly was to optimize turndown of the old boilers to maximize use of the CHP system. You have to produce most of the steam from the HRSG, he added, but need one of the backup boilers to pick up some load – say 10 percent to 15 percent – at the start of a batch. After about 20 minutes, the batch stabilizes, and you need less steam.
The software to run a potato-chip fryer is a very sophisticated multi-variable controller, and the CHP has to react accordingly. An Allen Bradley ControlLogix PLC (programmable logic controller) controls the HRSG and SCR and interfaces with the GT governor controls and duct-burner burner management system.
CPL Systems also provided a monitoring system for the switchgear, enabling the local utility to verify grid integrity and DOE to validate the grant. Frito-Lay uses Wonderware (Invensys Systems, Inc.) as the corporate-standard operator interface, thereby assuring consistency of reports across the enterprise.
Conner said that it took less than three days from first fire until the CHP was in integrated operation and meeting permitted emissions limits. Commissioning was coordinated and documented by Waldron, but CPL Systems did all the hands-on work required except for the gas turbine/generator.
Perhaps the most surprising aspect of the CHP system was the “control room.” It consisted of a small table, chair and laptop computer. That’s it. There wasn’t even a person in the chair because the state of Connecticut does not require a full-time operator for an installation the size of Frito-Lay’s. Rounds are made in the old boiler room, CHP building and control room every other hour. During the day, Fitzsimmons’ staff of five mechanics is responsible for the rounds; at night, process plant personnel – trained by Fitzsimmons – have the responsibility.