Carbide slag composite calcium-based sorbent based on biomass quenching and tempering and preparation method thereof

Abstract

The invention relates to the field of desulfurization in circulating fluidized bed furnace, in particular to a carbide slag composite calcium-based sorbent based on biomass quenching and tempering anda preparation method thereof. According to the sorbent, the biomass is mixed with the wet carbide slag to adjust the moisture in the carbide slag, so that the furnace charging problem of the wet carbide slag can be solved without a heating the drying process; the carbide slag is quenched and tempered by utilizing biomass, chemical modification of carbide slag is realized, rich soluble potassium is contained in the biomass, the migration of potassium in the biomass to the carbide slag surface of solid waste-based calcium-based sorbent can be realized through the quenching and tempering, so that the diffusion capacity of CaO in the CaSO4 dense product layer is improved during the desulfurization process, and the calcium conversion rate of the calcium carbide slag in the furnace when put into the furnace as small particle diameters can still be achieved when the carbide slag is put into the furnace with relatively large particle diameters; the sorbent has the advantages of high utilization efficiency, good desulfurization performance, short preparation process, low production cost and the like. Not only can the synergistic effective utilization of solid waste carbide slag and agricultural biomass be realized, but also the cost of desulfurization in the circulating fluidized bed furnace can be reduced.

Description

technical field [0001] The invention relates to the field of desulfurization in a circulating fluidized bed furnace, and more specifically relates to a calcium carbide slag composite calcium-based desulfurizer based on biomass conditioning and a preparation method thereof. Background technique [0002] At present, the most commonly used desulfurization agent for desulfurization in circulating fluidized bed furnace is calcium-based desulfurizer limestone, and its desulfurization efficiency is CaCO 3 The combined effect of the decomposition reaction and the CaO sulfidation reaction, due to the sulfidation product CaSO 4 (46cm 3 / mol) has a molar volume greater than that of CaCO 3 (36.9cm 3 / mol) and CaO (16.9cm 3 / mol), so that the sulfide product CaSO 4 The micropores on the surface of the decomposition product CaO are blocked, hindering the SO 2 Further reaction with unreacted CaO results in a calcium sulfation degree of only 25-45%, in order to achieve SO 2 Due to em...

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Problems solved by technology

Patent CN104190243A discloses a method for desulfurization of calcium carbide slag in coal-fired boilers. In this patent, calcium carbide slag is directly used for desulfurization in the furnace after physical drying to solve the problem that the water content of wet calcium carbide slag after pressure filtration is as high as 40%-50% %, the difficulty of directly entering the furnace; patent CN107213779A discloses a production system and production process of calcium carbide slag desulfurizer, which uses calcium carbide slag as a desulfurizer in the furnace after drying, crushing and separation, but the dried carbide slag Slag, due to the fine particle size, there are still some defects in the utilization of CFB boilers, such as unreasonable adjustment of air volume, which will cause calcium carbide slag to be blown out of the furnace before reaching the maximum conversion rate, thereby reducing the utilization rate of desulfurization agent

At home and abroad, calcium-based desulfurizers have also been chemically modified, mainly by adding some ions to increase the concentration of CaO in CaSO 4 Diffusion ability of dense product layer, patent CN105944552A discloses a calcium-based desulfurizer modified by barium ion doping, by adding BaCl 2 The prepared calcium-based desulfurizer has a large number of vacant site defects and is compatible with SO 2 The product layer formed after the reaction has a strong solid-state ion diffusion ability; patent CN103566719A discloses a method for producing TiCl 4 The generated chlorinated waste molten salt is crushed, dissolved in water, filtered, and step-by-step to remove impurities to obtain CaCO 3 Desulfurization agent, and modify it with NaCl aqueous solution. In the prior art, the modification of calcium-based desulfurizer by pure chemical reagents has the problems of high cost and difficulty in industrialization. Modification is carried out by waste source modifier, and the operation process involves chemical separation. Complicated procedures such as high processing costs

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