Combined Cycle Power Cleaning - Brazil

Precision Iceblast Corporation was hired to clean the finned tube bundles in two horizontal Vogt Heat Recovery Steam Generators located in Santo Antônio dos Lopes, Brazil. Precision Iceblast cleaned mineral deposits from the coldest one spiral finned heat transfer PreHeater module (approximately 73 feet x 29 feet) in HRSG #1 and the coldest two modules in HRSG #2.

Access to areas obtained from tube and clamp scaffolding supplied by PIC.

The most challenging part of the project was the very short notice given to proceed with the work. The project was discussed for months ahead of time, but the plant could not commit until only a month before their shutdown. Work visas are a time-consuming process in Brazil and getting equipment through customs is a very tedious process. Thankfully, the plant was very helpful and after a few delays we were able to proceed with a successful project.

The total project took fourteen 12-hour shifts to complete. After the cleaning was completed, the back pressure was reduced from 167.8 mmH2O to 159.2 mmH2O. The stack temperature was reduced from 97 degrees Celsius to 94 degrees Celsius. However, while the plant experienced some decline in efficiency, the major reason for cleaning was to remove sulfur from the tubes in order to ensure reliability of the boilers.

The plant explained, “the cleaning service was extremely important and necessary for the operational guarantee of our client’s two boilers. Ensuring the reliability and availability of your assets to positively meet your business model. Being necessary for our client to resort to the purchase of energy in the market according to the Settlement Price of Differences (PLD), to supply the contracted energy during the period of unavailability of the boiler.”

The plant is contracted for six months a year of availability to produce power to the grid. They need to be assured that when they are called on for power that their system will produce it without worry. Revenues of $44,168,976.00 are in jeopardy if their system is not reliable. Precision Iceblast was able to remove all of the sulfur from the tubes and help gain the plant confidence that the degradation of their tubes will not continue as each tube throughout the entire modules were sufficiently clean and the reliability of the boilers are solid.

Resources included two high-pressure blasting guns (PIC 56XD’s), one high-pressure compressor, and four laborers (one supervisor, one hole watch, one laborer and two blasters) per shift.