Semidry desulfurization product oxidized in fluidized bed through utilizing solid thermal carriers as initial heat source

Abstract

The invention relates to a method for oxidizing a semidry desulfurization product containing calcium sulfite. The method is characterized in that high-temperature solid thermal carriers are taken as an initial heat source, and oxidizing, waste heat recovery after the oxidizing and cooling are completed in a fluidized bed; smoke is generated when a combustion furnace burns coal or gas and exchanges heat with the solid thermal carriers in a gas-solid heat exchanger; high-temperature solid thermal carrier particles enter an oxidation fluidized bed through a J-shaped valve, the semidry desulfurization product to be oxidized is fed into the oxidation fluidized bed twice, partial raw materials are fed into a J-shaped valve outlet to be mixed with the solid thermal carriers, and the residual raw materials are fed from the middle of the oxidation fluidized bed. Oxidation-fluidization air is supplied from the bottom of the oxidation fluidized bed, materials which flow out from the bottom of a discharge end of the bed are lifted to enter a cyclone separator, coarse-grained solid thermal carriers are separated out and fed back to the gas-solid heat exchanger to be recycled, and gas and fine powder are lifted back to the oxidation fluidized bed. The high-temperature product which is completely oxidized flows into a cooling heat exchange fluidized bed.

Description

Technical field [0001] The invention is a technology for realizing waste resource utilization by oxidizing semi-dry desulfurization products, especially a technology for realizing waste resource utilization by using solid heat carrier as the primary heat source and oxidizing semi-dry desulfurization products in a fluidized bed. Background technique [0002] The semi-dry desulfurization process does not have the problem of serious equipment corrosion during wet desulfurization, so users are willing to adopt it, but its desulfurization products contain a large amount of calcium sulfite, which cannot be applied at present and can only be stacked, and when stacked, it will enter the nearby water body. The lack of oxygen in the relevant water due to the slow oxidation of calcium sulfite causes new pollution. [0003] Calcium sulfite oxidizes slowly at room temperature, and once it exceeds 350°C, the oxidation accelerates. After oxidation, calcium sulfite becomes anhydrous calciu...

AI Technical Summary

Problems solved by technology

Although heating can be directly heated with combustion flue gas as the heat source, direct heating of flue gas seems simple but has many disadvantages. First, the residence time of powder is short, generally only a few seconds. Combustion flue gas dilutes the oxygen concentration, and gas-solid contact Difficult to be sufficient, in order to achieve a full reaction, the oxidation air must be in excess, so the heat required to reach the initial temperature of rapid oxidation is correspondingly increased; when directly heated, the temperature of the gas and solid at the end of oxidation is much higher than that of the rapid oxidation due to the absorption of reaction heat. The initial temperature of oxidation, the large quantity and high temperature lead to a large amount of waste heat to be processed, and the subsequent waste heat recovery capacity is limited, and the thermal efficiency is low; in addition, the heat transfer coefficient of the gas flushing the heating surface is small, and the powder is easy to contaminate the heating surface, resulting in There are too many heating surfaces for waste heat recovery and product cooling; the total amount of combustion flue gas and exhaust gas is too large, and the purification equipment is huge

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