Two chemists have patented what they say could be a better way to remove the harmful components of acid rain from the smokestacks of power plants and factories.
Acid rain is caused by sulfates and nitrates--mostly from the combustion of fossil fuels--that mix with water vapor in the atmosphere to form sulfuric and nitric acids.
The extra acidity produced by acid rain can kill fish directly, slow bacterial decomposition of natural material and can subject people to lead poisoning by corroding lead water pipe.
The National Academy of Sciences released a report June 29 saying it had found a direct relationship between sulfur dioxide emissions and acid rain, and that cutting the emissions in half would reduce acid rainfall by the same proportion. The report drew support from environmentalists and attacks from the coal industry.
The process, developed by Richard I. Martinez and John T. Herron of the National Bureau of Standards, removes some of the acid rain-forming substances from smoke and combines them with industrial flue gas in a chamber, in effect moving the reaction from the atmosphere to a controlled area.
The acids produced could be removed easily and safely and converted into fertilizers, the scientists say.
"The one thing we're taught from high school on is that chemistry is generic: If it happens here in the lab , it can happen anywhere," Martinez said, explaining how the NBS chemists hit upon the concept of controlling the formation of the acids by relocating the process.
Currently, sulfur dioxide is removed from exhaust gas by circulating the gas through powdered limestone suspended in water. But the process gums up the equipment and forms harmful calcium sulfate, which usually has to be disposed of in water-tight containers at industrial waste sites.
"We started off in 1974 trying to discover how S02 sulfur dioxide gets oxidized to form sulfuric acid and sodium sulfate," Herron said. They were studying atmospheric chemistry and pollution. They knew from other research how many of the chemical reactions that create acid rain took place, but the exact nature of the S02 formation wasn't clear. Painstaking research allowed them to fill in the gaps and devise a way of combatting the problem.
The NBS Chemical Kinetics Division, which Herron heads, has a staff of 30, 20 labs and a yearly budget of $2 million. Herron has been at NBS since 1957; Martinez, since 1976.
About 50 companies have inquired about their patent. Some will test the concept in the lab, and some might go on to test it in pilot plants before obtaining a license from the federal government.
Martinez believes that the big problem in translating their patent into a working procedure will be cost. "Somebody's going to have to underwrite it," he said, estimating that it will be between one and two years "before we know that there is or isn't a definite interest" in their process.
Companies that decide to seek licenses will have to deal with the National Technical Information Service, which was set up "to produce wider private-sector use of government-developed technology," according to Douglas Campion, patent program coordinator for NTIS.
The service receives copies of new patent applications filed by government agencies and selects those believed to have the most potential for commericial use. NTIS employes then inform all companies of the patents' existence through a weekly publication, "Government Inventions for Licensing," send letters to those companies they think will be interested in particular patents, and submit a title listing of new inventions for inclusion in the Federal Register.
A company interested in an invention from one of the government agencies represented by the NTIS must fill out a two-page formal application for a license and attach a three- or four-page plan detailing the time and effort to be spent on commericalizing the process. A company normally will ask for an exclusive license, but can ask for a nonexclusive license or licenses involving sharing with one or more other companies.
NTIS gives preference to requests for a nonexclusive license. It publishes its intent to grant an exclusive license in the Federal Register and then must wait 60 days for public reaction, Campion says. Frequently additional companies, after seeing the notice, also will request an exclusive license or ask for a nonexclusive license. The latter request will generate nonexclusive licenses for all. Only about 1 percent of the time does the NTIS have to choose among two requests for an exclusive license. About one-third of the licenses it grants are exclusive, he said.
Fees for obtaining a license underwrite the NTIS program, and any excess funds are given to the Treasury.
Martinez and Herron have reason to have more than an academic interest in whether their patented process is licensed. Under an incentive program that began in 1977, NTIS pays inventors 15 percent of what the government gets in licensing fees, up to $35,000 per invention. "This has stimulated a lot of interest among employe inventors, as you might imagine," Campion said.