Method for reducing calcium-sulfur ratio in nid semi-dry desulfurization process

Abstract

The invention discloses a method for reducing calcium sulfur ratio of an NID semi-dry desulfurization process. The method comprises the following steps: (1) smoke enters a desulfurization reactor, and then is subjected to desulfurization reaction together with a desulfurizing agent and calculating ash added with humidifying water in a reactor, the introduced smoke temperature is controlled to be 100-150 DEG C, or / and the discharged smoke temperature is higher than the smoke dew temperature by 5-15 DEG C by regulating the amount and the temperature of humidifying water; (2) the smoke subjected to desulfurization enters a dust remover to be subjected to dust removal, part of separated dust is discharged, and the other part of separated dust is taken as circulating ash which enters the reactor to be subjected to circulating desulfurization. The using amount of the humidifying water is increased by increasing the temperature of introduced smoke subjected to desulfurization, reducing the temperature of discharged smoke subjected to desulfurization, and increasing the temperature of the humidifying water, and further, the amount of the circulating ash is increased, so that the purposes of reducing the using amount of the desulfurizing agent and lowering the calcium sulfur ratio can be achieved, and the calcium sulfur ratio is reduced to be below 1.5 from more than 2.5.

Description

technical field [0001] The invention relates to flue gas desulfurization technology, in particular to a method for reducing the calcium-sulfur ratio of the NID semi-dry desulfurization process. Background technique [0002] The NID semi-dry desulfurization process is an integrated technology of desulfurization and dust removal. The NID desulfurization and dust removal system includes four core systems: desulfurization reactor, high-concentration dust collector (bag filter ESP or electrostatic precipitator FF), mixer, and circulating ash conveying system , the system utilizes a desulfurizer containing CaO or hydrated lime and SO 2 The reaction produces CaSO 3 and CaSO 4 , the dust collected by the dust collector is mixed with CaO for humidification and then enters the inlet flue and smoke box of the dust collector, and the cycle is repeated. Among them, the high-temperature sintering flue gas from the pre-dust collector such as ESP or FF enters In the reactor, the circulat...

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Problems solved by technology

[0003] The NID semi-dry desulfurization process has been widely used in recent years due to its advantages of small investment, low land occupation, and no waste water generation. However, with the advancement of the project, the problems exposed by this process have become increasingly prominent, and there is a high calcium-sulfur ratio in the system. However, the calcium-sulfur ratio is as high as 2.0-3.0, which is 30%-100% higher than other semi-dry desulfurization technologies, such as: LJS circulating fluidized bed method, SDA rotary spray method, etc. The higher calcium-sulfur ratio not only causes enterprises to The cost of desulfurization remains high, and at the same time, a large amount of desulfurization ash is produced, which is difficult to use as resources, causing secondary pollution to the surrounding ecological environment

At present, the research on the semi-dry desulfurization system mainly focuses on the resource utilization of desulfurization ash, and rarely involves the high calcium-sulfur ratio of the NID semi-dry desulfurization process

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