Method for preparing circulating fluidized bed boiler ash based flue gas mercury removal adsorbent for coal-fired power plant

Abstract

The invention relates to a method for preparing a circulating fluidized bed boiler ash based flue gas mercury removal adsorbent for a coal-fired power plant. The method is used for solving the problem that energy-saving, environment-friendly and simply-operated methods for preparing the circulating fluidized bed boiler ash based flue gas mercury removal adsorbent for the coal-fired power plant do not exist currently. The method is characterized by comprising the following steps: (1) weighing the raw materials in parts by weight: 60-80 parts of circulating fluidized bed boiler ash, 10-15 parts of clay, 5-10 parts of activated carbon and 5-15 parts of bromide, adding water to mix uniformly, dipping for 4-8 hours, and stirring at a constant speed by using a stirrer during dipping modification; (2) preparing spherical granules from a dipping-modified adsorbent by a granulator by adopting a cold-curing forming process, and naturally drying for 10-14 hours; (3) drying naturally-dried spherical adsorbent granules in a vacuum drying oven for 12-24 hours, then, taking out, putting into a drier and cooling to room temperature, thereby obtaining the circulating fluidized bed boiler ash based flue gas mercury removal adsorbent. The method has the advantages that the cost can be reduced effectively, and the operation is simple.

Description

technical field [0001] The invention relates to a preparation method of a flue gas demercury adsorbent, in particular to a preparation method of a sulfur-fixed ash-based coal-fired power plant flue gas Gas demercury sorbent method. Background technique [0002] In the process of coal combustion, the flue gas not only contains NO x , SO x And dust, but also contains Hg, As and other volatile, toxic and harmful elements. According to statistics, the global annual Hg emission is 4400-7500 tons, about half of which comes from Asia. The Hg content in most coals in my country is between 0.01-1mg / kg, and the annual Hg emission of power plants exceeds 300 tons. Hg in the atmosphere can enter the human body through the respiratory system or the food chain, seriously endangering human health. Especially methylmercury can pass through the placental barrier, damage the nervous system, immune system and circulatory system of newborns, and affect the intelligence of newborns. [000...

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Problems solved by technology

For example, the publication date is October 13, 2010, and the Chinese patent with the publication number CN101856607A discloses a flue gas mercury removal adsorbent, which adopts the following components by weight: 10-25% 2-5% clay, 2-5% polyethylene, 2-5% rice husk, 5-10% calcium oxide, and the balance is fly ash; after mixing the components, add water and mix thoroughly, and then extrude and granulate into Particles with a particle size of 30-50mm are obtained by sintering at a high temperature of 900-1100°C for 2-4 hours; although the main raw material of the flue gas demercury adsorbent is fly ash, which reduces the cost of raw materials, it needs to be processed at 900-1100°C. Sintering at a high temperature of 1100°C for 2-4 hours consumes a lot of energy, which is not conducive to energy saving and environmental protection

Another example is that the publication date is March 16, 2011, and the Chinese patent with the publication number CN101985099A discloses a method for preparing a flue gas mercury removal adsorbent. The preparation method of the flue gas mercury removal adsorbent includes: biomass heat Preparation of pyrolysis: put biomass pyrolysis coke into a container containing ammonium halide solution for immersion, and stir continuously for 8-12 hours; filter to remove biomass pyrolysis coke moisture, and dry at 45-50°C ; Although the preparation method of this adsorbent is simple, the cost is low, and it can effectively adsorb mercury in the flue gas, but the adsorption effect is not ideal.

[0004] To sum up, there is currently no energy-saving, environmentally friendly, cost-effective, and simple-to-operate method for preparing a sulfur-fixing ash-based coal-fired power plant flue gas mercury removal adsorbent.

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