Air Quality and Stationary Source Emission Control (1975) / Chapter Skim
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10 Some Methods of Reducing Sulfur Oxides from Power Plants
10 Some Methods of Reducing Sulfur Oxides from Power Plants
Pages 354-384
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From page 354... ...
They include: ( 1) improved efficiency of conversion of fuel to electricity (this would reduce pollutant emissions per unit of electricity generated}; (2} shift to nuclear generation as rapidly as possible since no sulf ur oxide (or particulate} is emitted from nuclear plants; (3} shift fossil fuel plants to lower sulfur fuels; (4} removal of sulfur from coal before combustion, or of the sulfur oxide after combustion, but before it enters the stack: the techniques to be considered are 354
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From page 355... ...
; (b) solvent ref ined coal; (c} low sulfur, low BTU gas from coal; {d} f luidized bed combustion; {5)
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From page 356... ...
Steam turbine-gas turbine combined cycles are currently being used commercially on medium sized boilers using natural gas as a fuel ~ However, plants using these cycles would be unable to use coal as a fuel (unless it were first gasified arid the particulates removed) ; they do rot operate at suf £iciently high temperatures to get the high conversion efficiencies desired, and when the temperatures are increased, do not have the service lif e required in a base load utility E>lant.
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From page 357... ...
A demonstration size unit, using natural gas as a fuel, is now being tested in the USSR. Even when using clean fuel, MHD ducts still need to be developed that will have a useful life in the extreme temperature conditions expected in ducts; methods for recovering the seed material and removing nitrogen oxides must be found and materials must be developed for the electrodes that will have the needed electrical properties and the ability to withstand high temperatures for extended periods.
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From page 358... ...
Efficiencies as high as 50-55 percent might be obtained in binary plants but, as with the other advanced power cycles, extensive commercial utilization will not occur until the period beyond 1985.
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From page 359... ...
He l :t , .i :\ ? SHIFT TO NUCLEAR GENERATION AS RAPIDLY AS POSSIBLE summary If the necessary Federal and State actions are taken to restore the originally planned nuclear capacity twith associated reduction in particulate and sulf ur oxide emissions} coal consumption could be reduced by about 75 million tons i n 1980.
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From page 360... ...
If these actions are taken and 30,000 MW of nuclear capacity, which would otherwise not be operational, are on stream by 1980 it would reduce coal consumption in that year by about 75 million tons. However.
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From page 361... ...
Low sulfur western coals will }'e usable in new coal fired plants designed to burn them if transportation capacity is increased but their use in retro-f itted plants will be limited. Natural Gas it, ;5 Since 1968, except for the Alaskan natural gas discoveries, the amount of gas that has been consumed each year has been greater than that which has been discovered.
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From page 362... ...
The bulk of the petroleum used by the utility industry, however, is residual fuel oil burned to supply the heat for base load steam electric generating plants. some of the plants using residual oil were converted from coal to oil to meet the sulfur oxide air pollution regulations.
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From page 363... ...
If the OCS Atlantic leasing were to start as early as 1975 and if important dis coveries were made, it would be 197 9 or 1 9 80 before large volumes of these fuels would be available for use from this source. Moreover, it is abvious that use of these fuels, which are in short supply now and are certain to be In the future, by the utility industry would not represent the best use of these fuls to obtain short term environmental relief.
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From page 364... ...
6 Bullion tons respectively, for a total of 45.6 million for the three year period. Deep mining capacity, therefore, decreased 16.6 million tons in three years.
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From page 365... ...
tlllll: Total net new mine capacity added between '''''l~ ~ 1970 and 1972 was about 120 million tons. With '''''l: ~ the uncertain future of sulfur oxide regulations 885.e.g 4.
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From page 366... ...
The EPA issued a reports using updated Bureau of Mines data that indicated that the demand f or low sulfur fuels would be 273, 295 and 329 million tons in 1975, 1977 and 1980 respectively. These estimates were based on restrictive assumptions transferring coal from where it is unacceptable to where it is acceptable.
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From page 367... ...
However, and additional 5 0 million tons of less than 1 percent sulfur coal will be produced and could be used where it is needed most. The very large reserves of low sulfur coal are found in the West at great distances from the markets and in areas where the construction of large new mines would have a major impact on socio-economic conditions in the region.
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From page 368... ...
REMOVE SULFUR FROM COAL BEFORE AND DURING COMBUSTION Summary Proven conventional coal cleaning methods can reduce the sulfur content of coal significantly. However, unless the original sulf ur content is already low enough to nearly meet the sulfur oxide emission standards, conventional coal cleaning methods will not bring most coals into compliance with source performance standards for Sax.
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From page 369... ...
If f luidized bed combustion can be successfully developed, it should produce a c, ean fuel for boiler use that is less costly than either a low sulfur - low ash coal or low BTU - low sulfur gas produced from coal. Conventional Coal Cleaning Technology Besides substituting a low sulfur for a high sulfur fuel to reduce the SOx formed, the sulfur can be removed from the fuel before combustion.
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From page 370... ...
At a 9 0 percent yield only about 15 percent of the coals could be cleaned to 1 percent sulfur or less. The Illinois Geological Survey conducted tests on 67 Illinois coals ~ with most of the raw coals herring a sulfur content of 3 to 5 percent.
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From page 371... ...
Under normal circumstances a coal preparation plant using any of the various commercial technology can be installed in from 1 1~2 - 2 1~2 years. Advanced Coal Cleaning Technology All of the coal preparation techniques now used commercially use physical processes for the separation of impurities and these methods are unable to remove all of either the ash or sulfur.
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From page 372... ...
However, this process does not remove organic sulfur and reasonably good pyritic sulfur reduction is obtained by conventional methods at much lower costs, it is improbable that any of the advanced sulfur removal processes will be widely used by 1980 or even 1 985.
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From page 373... ...
A much smaller pilot plant ~ 5 tons~day) using the same process was constructed by Southern services Inc.
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From page 374... ...
In a few installations the hydrogen sulfide was removed. When interest in coal gasification was revived in this country it was because the pipeline transmission companies and the gas distribution companies became concerned that they would be unable to continue their growth as natural gas supplies were depleted.
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From page 375... ...
Three processes for making town gas from coal had been used in a significant number of instal rations so that they can be considered commercial. There are the f ixed bed, high pressure Lurgi process ~ the atmospheric pressure entrained Kippers Totzek process and teh Winkler f luid bed atmospheric process of Dailey Power Gas, Inc.
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From page 376... ...
Although it is believed that most of the processes that were under investigation f or making high BTU could also be used f or making low BTU gas there has been no testing of any of the commercial processes (Lurgi, Kioppers Totzek or Davey Power Gas, Incorporated)
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From page 377... ...
Combustion of low-BTU gas produces very low emissions of NOx. Low Sulfur Oil from Coal Liquid fuel f rom coal was produced during World War II in Germany using two doff ferent processes and the product was used as a refinery f eedstock.
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From page 378... ...
If a successful modification of any of these processes can be accomplished, it might be possible to have a f irst commercial plant in operation in the pried ~ 982- 19 83 ~ If any of processes still at an early state of investigation must be developed for producing low-sulfur oil for boiler fuel, commercial plants will probably not be in operation until 1985 to 1990. Fluidized Bed Combustion Because of the shift in interest away f rom producing synthetic high BTU pipeline gas and refinery feedstock from coal to producing a clean boiler fuel, methods for using coal directly have also been receiving increasing .
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From page 379... ...
Fluidized bed combustion, another method of burning coal directly in boilers, offers the potential for overcoming most of the difficulties that arise when pulverized Coal is used. With fluidized bed combustion sulfur oxide and nitrogen emissions can be reduced, the efficiency and reliability of the units are expected to be increased and the size, weight and cost of the boiler may be reduced.
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From page 380... ...
. A pressurized fluidized bed 1~8 MW pilot development unit is to be used to provide design, materials and environmental information for the construction of larger pilot plant unit.
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From page 381... ...
I_. _; _li SHIFT FUEL CONSUMPTION FROM ELECTRICITY TO PIPELINE GRADE GAS MADE FROM CoAL Summary The average cost of heating structures with natural gas made from coal is about one-half that of the average costs of heating the structure with electricity made from coal when using resistance heating.
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From page 382... ...
All the synthetic gas would not require new distribution facilities since part of that gas would serve as a replacement for the decline in natural gas production. However, assuming that new facilities would be needed for all of the gas and that new distribution costs would be 50 percent more than the 1971 costs, then total costs per usable BTU to the consumer would be $5~70 to $6.50 per million BTU.
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From page 383... ...
1974. 8 Supplemental natural gas imports were not thought to be a useful method to supplement domestic supplies until the late 1 9 6 Us because of the high cost of liquifying and
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From page 384... ...
384 transporting the natural gas in the f arm of a ~rerv low temperature liquid.
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