Limestone slurry supply system and adjustment method with wide load adjustment

Abstract

The invention relates to a limestone slurry supply system with wide load adjustment and an adjusting method based thereon and belongs to the technical field of desulfurization; the limestone slurry supply system comprises a limestone slurry tank, an outlet of the limestone slurry tank is connected to an inlet of a limestone slurry pump, an outlet of the limestone slurry pump is connected to an inlet of a limestone slurry density measuring pipeline and an inlet of a limestone slurry flow measuring pipeline, an outlet of the limestone slurry density measuring pipeline is connected to an inlet of the limestone slurry tank, an outlet of the limestone slurry flow measuring pipeline is connected to a desulfurization absorbing column, and the inlet of the limestone slurry pump is also connected with a process water pipeline, wherein the limestone slurry pump is connected with a frequency converter. The invention also relates to an adjusting method based on the limestone slurry supply system with wide load adjustment. The problem that limestone addition is unable to vary in real time along with SO2 load under low SO2 load is solved, and pH value and SO2 emission concentration are stably controlled for a desulfurization system.

Description

technical field [0001] The invention relates to a wide-load regulated limestone slurry supply system and a regulating method, belonging to the technical field of desulfurization. Background technique [0002] Limestone-gypsum wet desulfurization technology is the flue gas desulfurization technology for power plant coal-fired boilers with the widest application range and the most mature technology in the world. Limestone powder is used as absorbent. In order to control the amount of limestone added, limestone powder and water are usually mixed in a certain proportion to form limestone slurry, and limestone is added to the desulfurization tower through the limestone slurry supply system. [0003] The existing limestone slurry supply system generally adopts the slurry supply mode of the variable frequency pump, and the amount of limestone added is controlled by adjusting the flow rate of the limestone slurry. Because the mass concentration of limestone in the limestone slurry ...

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Problems solved by technology

[0005] The existing limestone slurry supply system adopts a single frequency conversion adjustment method for the slurry supply pump, which can only be used in SO 2 The real-time adjustment of limestone addition can only be realized when the load is greater than 50%.

Therefore, when SO 2 When the load varies from 50% to 100%, the amount of limestone added to the existing limestone slurry supply system can increase with the SO 2 Real-time adjustment for load changes; when SO 2 When the load is lower than 50%, if you continue to reduce the frequency of the slurry pump to supply the slurry, it will lead to the deposition of slurry in the pipeline, which will endanger the safe operation of the slurry supply system

In order to avoid the deposition of slurry in the pipeline, the existing limestone slurry supply system adopts the intermittent slurry supply method of frequently starting and stopping the limestone slurry pump, which brings the following problems: (1) The amount of limestone added can no longer follow the SO 2 Real-time adjustment due to load changes, resulting in large changes in the pH value of the desulfurization system, resulting in SO 2 Risk of Excessive Concentration Emissions

(2) The limestone slurry pump needs to be started and stopped frequently, which reduces the service life of the pump

(3) Every time the limestone slurry pump is out of service, in order to prevent the slurry from depositing in the pipeline, it is necessary to flush the slurry supply pipeline system, which consumes a large amount of process water

At the same time, the annual utilization hours of coal-fired power stations continued to decrease, and the SO 2 The load has been in a low state for a long time, and the existing limestone slurry supply system can no longer meet the requirements of low SO 2 Production requirements of ultra-low concentration emission standards under load conditions

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