![]() ![]() The sulphur-rich gas (SO 2, N 2, CO 2 and H 2O) flows to an acid plant for conventional production of marketable sulphuric acid, and there are no steam or SO 3 plume releases. The coke falls downwards through three indirect heat exchanger sections for preheating, heating and cooling the regenerated coke, which is then discharged through a lock hopper. The pollutant-laden activated coke sorbent is processed in a thermal regenerator vessel which completes the reduction of NOx to N 2 and driving off the SOx.Īctivated coke at flue gas temperatures is fed through a lock hopper to the top of the regenerator. ![]() Impact with the coke pellets across the moving bed also captures particulates. The total carbon surface area in contact with flue gas and the contact times are much higher than those for activated carbon injection of an ESP or FF. The process does not consume water or lose water to waste disposal streams, and performance improves with lower back-end flue gas temperatures. The activated coke removes SO 2, SO 3, NOx, Hg, and other pollutants through adsorption, chemisorption and catalytic reactions that are enhanced in the presence of ammonia. “Combined with other methods, ReACT retrofits to coal-fired plants to cut SO 2 and NOx to only single-digit ppm levels.” And, because the process uses only 1% of the water of conventional wFGD, it suits sites with difficult water supply, treatment or discharge. The technique is interesting to utilities burning PRB (Powder River Basin) or other low-sulphur coals. ![]() It can capture more than 98% of any remaining SO 2 and SO 3, 30% to 60% NOx, 90% mercury and 50% particulates. ReACT filters out pollutants using activated coke as a dry regenerable adsorbent, and is inserted downstream of a primary particulate control device, typically an ESP or fabric filter (FF). Combined with other methods, it retrofits to coal-fired plants to cut SO 2 and NOx to only single-digit ppm levels – comparable with natural gas fired plants. Perhaps the most promising technique is J-Power Entech’s ReACT (regenerative activated coke technology). Individually, though, these are not enough and flue gases need further processing for proper reductions. SO 2 levels in today’s coal-fired power plants can be reduced by wFGD (wet flue gas desulphurisation) or spray dryer absorption (SDA) – for example, NOx by selective catalytic reduction (SCR) and mercury by coal washing. ![]()
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