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Chemical Company Trusts Cleaver-Brooks HRSG to Maintain Power for Production

Case Study

  • Company: Chemical Manufacturer
  • Industry: Manufacturing
  • Location: Louisiana
  • Profile: The company wanted a combined heat and power solution to improve plant reliability, reduce electricity and lower steam costs.
  • Challenge: Eliminate the need to purge the HRSG when the gas turbine is forced into outage.
  • Solution: Cleaver-Brooks custom designed a Max-Fire® HRSG with auto transfer from supplemental-firing to fresh-air firing, and vice versa.
  • Results: When Hurrican Isaac hit New Orleans, the manufacturer was able to maintain production for four days while the grid around it was down.

One of the world’s leading specialty chemical companies operates plants throughout the world, including one in Louisiana that produces chemicals and polymers for a variety of uses from consumer goods to agricultural applications.

Company executives were seeking a way to minimize the downtime caused by frequent outages at the local electric utility. Located in the Gulf Coast region, hurricane-related outages are commonplace. More troubling, however, are the non-weather-related outages that occur about 10 times a year.

The company’s management team calculated the lost time due to power failures and hurricane outages over a period of one year. The annual loss was 154 hours. Power failures amounted to 116 hours, and production losses associated with hurricane outages amounted to 38 hours.

In addition to the downtime, when the local utility was not providing power, the plant could not keep raw materials such as acrylic acid cool. According to the company’s director of engineering, that was a major concern because at high temperatures more site reactions occur. If acrylic acid becomes too warm, it can polymerize. When the plant loses power, there is less conversion efficiency, which substantially increases operational costs.

The company began pursuing a combined heat and power (CHP) solution to improve plant reliability, reduce electricity and lower steam costs. The requirement was for the combustion gas turbine to produce 4.5 MWe along with a Heat Recovery Steam Generator (HRSG) at the plant to produce at least 80,000 lb/hr of high pressure steam.

When it came time to select the HRSG manufacturer, the company obtained proposals from multiple manufacturers. They chose Cleaver-Brooks due to their experience, their overall proposal and the engineering expertise of Cleaver-Brooks Engineered Boiler Systems.

“We knew that adding the ability to automatically transfer from supplemental-firing to freshair firing, or vice-versa, would be the key to this project,” recalled Greg Kaup, sales manager for Cleaver-Brooks. “In the event the gas turbine is forced into outage, eliminating the need to purge the HRSG would give the company increased operating flexibility by keeping the HRSG online and contribute to the success of the project.”

Kaup added, “Since Cleaver-Brooks designs and manufactures all the major components of our systems, including the controls, we were confident that the auto-transfer process would be seamless, which gives customers true peace-of-mind.”

Cleaver-Brooks provided a complete scope of supply, starting with the turbine exhaust ductwork and finishing at the main stack flue gas outlet. Equipment supplied included a custom-designed Max-Fire® HRSG with integral water-cooled furnace capable of handling high firing temperatures, a Cleaver-Brooks duct burner capable of operating in supplemental or fresh-air firing modes, and an integrated control system comprised of a PLC-based Burner Management System (BMS) and HRSG Integrated Control System (ICS). To round out the “power island” package, a fresh-air fan with control and seal-air dampers was provided, along with a diverter with dedicated bypass stack and a guillotine isolation damper. Cleaver-Brooks also provided a deaerator to treat incoming feedwater. In addition, supervisory start-up services were included.

The HRSG is capable of generating 85,000 lb/hr of 400 psig steam during both supplemental and fresh-air firing modes with minimal back pressure on the gas turbine. Unfired performance yields over 25,000 lb/hr.

A year after the equipment was installed, it was put to the ultimate test and passed with flying colors.

When Hurricane Isaac hit New Orleans in 2012, the manufacturer was able to maintain production for four days while the grid around it was down. As a result, the company profited financially.

In addition to the hundreds of thousands of dollars the plant is adding to its bottom line annually by consistently maintaining its production, it qualified for a 10% investment tax credit from the Department of the Treasury for its capital investment in cogeneration. Cleaver-Brooks helped the company perform the efficiency calculations required to support the grant application.

Kaup said, “This project exemplified how an integrated HRSG supplier can collaborate with an industrial client to provide a flexible combined heat and power plant.”