Removing SOn in heating plant boilers Research-Cottrell, the US. licensee of the Swedish process of A. 6. Bahco, cleans up emissions from coal-fired boilers; the process is useful on small installations of the 100 MW size-small boilers, industrial boilers, and small power plant boilers
Historians may remember 1977 as the year of the coal lump instead of the snake. The energy crunch hit hard for millions who still face the prospects of dwindling natural gas supplies and soaring electrical costs. Experts say that the US. has an unlimited coal resource within its continental borders that could generate our electrical and heating requirements for the next 500 years. But what about the pollution problem? Near Columbus, Ohio, is Strategic Air Command, Rickenbacker Air Force Base. The field was built in 1942 and was designed to be heated with coal. The plant houses eight boilers and an impressive number of smoke stacks. It operates much to the dismay of local residents, around the clock, 365 days a year. Only 12 months ago the plant was the source of a 12-mile-long smoke screen.
How it works In back of the heating plant is a silo filled with lime. The game plan calls for the smoke to be blown into the scrubber, which contains two venturis. The bottom of the scrubber is filled with a lime solution; another pump with lime solution is located halfway up the chimney-shaped tower. Large pumps churn the liquid. The smoke is forced through the lower venturi into the churning lime, which sponges up harmful sulphur oxides. The process is again repeated through the upper venturi, with the gases passing through a fan that spins them upward like a tornado. The remaining suspended particles are spun out of the updraft, strike the inner walls of the chamber, and fall harmlessly to the bottom of the tank. The sanitized gases then leave the scrubber stack in the form of harmless steam. “The system is not without its drawbacks,” Rasor continues. “There is a sludge by-product, calcium sulfate. This thick black liquid is pumped into a nearby rubber-lined lagoon. The pool will take 5 years worth of sludge. The Japanese have a Bahco system similar to ours and have been adding chemicals to the by-product to make gypsum wall board.” Since the Rickenbacker scrubber is the only one in the US., the Environmental Protection Agency keeps close tabs on the operation. The scrubber has far surpassed present EPA emission standards for this type of system, which means that the Air Force experiment is doing the
Civil engineer Jim Rasor, said, ”Rickenbacker had plans to convert to oil in 1973. At the time bids were being sent out for the job, the Pentagon was looking at Research-Cottrell and the Swedish Bahco scrubber. R-C obtained a license to use the technology in the U S . and Rickenbacker AFB is where it went.” The Air Force experimental pollution abatement system with the Bahco scrubber is one of a kind in the U S . and :Ah has been in ooeration for almost a vear. JUU. Because of t i e importance of coal as an The project at the AF base has been alternate fuel, Rickenbacker has become saving money by burning a cheaper, a common name in environmental circatty available, high-sulphur coal, and cles. even with the added cost of the lime they are still operating below the Drice of fuel oil. The Rickenbacker project may beSO2 removal: How the come a blueprint for future American Bahco process works coal-burning plants and could lead to _Tcz greater use of our most abundant energy Stack -,resource.
Make-up mm3Wad&
water supply
Civil engineer Rasor “AF experiment is doing the job”
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Sludge pump
Volume 11, Number 7, July 1977
645
