A circulating fluidized bed boiler oxygen-enriched combustion dry desulfurization system and method

Abstract

The invention discloses a circulating fluidized bed boiler oxygen-enriched combustion dry desulphurization system and method. The dry desulphurization system comprises a hearth, a coal feeding hole, a primary air chamber, an air distribution device, a high-temperature cyclone separator, a tail flue, a coal economizer and a return device, wherein a desulfurizer feeding hole is formed in the coal feeding hole or / and in a return leg of the return device; a medium-temperature cyclone separator is arranged on the tail flue on the rear of the coal economizer; a return bin of the medium-temperature cyclone separator is connected with the hearth through a pipeline; a central drum of the medium-temperature cyclone separator is connected with the primary air chamber through an air hose and a primary air hose and is connected with the hearth through the air hose and a secondary air hose; an induced draft fan is arranged on the air hose; an oxygen injection device is arranged on at least one of the air hose, the primary air hose and the second air hose. The circulating fluidized bed boiler oxygen-enriched combustion dry desulphurization system can effectively solve the SOx up-to-standard discharge problem of a boiler, increase the utilization ratio of limestone, reduce consumption of limestone, improve desulphurization efficiency, realize efficient and economical desulphurization in the boiler as well as CO2 enrichment, facilitate compression, purification, utilization, sealing and storage of CO2, and meet environmental protection demand.

Description

technical field [0001] The invention relates to an oxygen-enriched combustion dry desulfurization system and method for a circulating fluidized bed boiler. Background technique [0002] Thermal power generation is a major source of primary energy consumption and pollutant discharge in my country, and is also one of the important sources of air pollutants. 2 , SO 2 , NOx emissions accounted for more than 40% of the total emissions. The outline of the "Twelfth Five-Year Plan" proposes that by the end of 2015, the energy consumption per unit of GDP will be reduced by 16% compared with 2010, and SO 2 , NOx emissions were reduced by 8%, 10%. At the Copenhagen Climate Change Conference in 2009, the Chinese government announced a clear and quantitative goal to control greenhouse gas emissions, and decided to reduce carbon dioxide emissions per unit of GDP by 40% to 45% compared with 2005 by 2020, which means that my country will achieve CO2 emissions. 2 large-scale emission red...

AI Technical Summary

Problems solved by technology

At this time, it is difficult to ensure that the SO2 of CFB boiler flue gas is not guaranteed even if the desulfurization efficiency is increased to 95% by adopting measures such as technical optimization and increasing Ca / S, etc. 2 The emission concentration reaches the standard, and at the same time, it is difficult to realize CO 2 enrichment, CO 2 Difficult to centralize subsequent processing, CO 2 Emissions are difficult to control and easy to exceed the standard

If a separate limestone-gypsum wet desulfurization system or other high-efficiency desulfurization system is established for the CFB boiler, so that the desulfurization efficiency can reach more than 95%, it will require a huge increase in investment and operating costs, making the CFB boiler lose compared with the pulverized coal boiler. The advantage of low cost of pollutant control

On the other hand, the wet desulfurization process is not only complex in system, high in water consumption, and high in desulfurization costs, it is subject to certain application restrictions in my country's vast economically underdeveloped and water-deficient areas; and attention, the control of PM2.5 is bound to become a major trend, and another major problem facing wet desulfurization is SO 3 The removal efficiency is low, SO after desulfurization 3 Acid mist concentration is difficult to control, SO 3 Acid mist will increase the concentration of PM2.5 in exhaust smoke, which is difficult to meet the needs of environmental protection

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