Biomass has the characteristics of low carbon, high volatile matter, low sulfur and high oxygen, low density and large volume. The calorific value of 2 tons of biomass can equal 1 ton of standard coal. my country is rich in biomass resources, and the annual production volume accounts for about 50% of the annual coal mining volume, which is equivalent to 656 million tons of standard coal. Biomass fuel should use grate furnace or CFB boiler for low-temperature combustion. The concentration of SO2 and NOx in the flue gas is low, which is a possible source of green. Biomass combustion power generation occupies an important strategic position in the utilization of new energy. Biomass is not flammable, combustion products are easy to accumulate ash and slag, and are ignited twice. The flue gas temperature changes greatly. The flue gas is light and fine, and it is difficult to remove dust. A bag filter should be used, supplemented by a cyclone. , Pre-coating, spray temperature control, coagulation and weight gain and other technical measures.
The successful cases of biomass power plant adopting bag filter include: In 2007, the design of dust removal project of 2×12MW unit of CECEP Suqian Biomass Power Plant adopted line spray pulse bag filter with glass fiber coated filter material; Jiangsu Lianmei Power Plant 75t /h Biomass boiler, fired with wheat and rice straw, designed with line jet pulse bag filter, equipped with PPS/PTFE composite filter material. In 2008, a 2×75t/hCFB boiler of a biomass power plant in Shandong was designed to adopt a line jet pulse bag filter with PPS filter material. However, there are many problems after it is put into operation: one is the high resistance (2200Pa) operation of the dust collector due to high design flow rate, incorrect temperature control, paste bag, etc.; second, the oxygen content of the flue gas is as high as 16%, at 160℃ Under the condition of high temperature of 180℃, the PPS filter bag is oxidized and corroded, and sparks burn, and the filter bag is seriously damaged. After the expansion of the dust collector, the use of glass fiber coated filter media, and the improvement of air flow distribution, the problem was solved.
The valve plate of the air chamber remains in the recovery state before the air chamber is sprayed and cleaned. When the cylinder is opened, the valve plate installed in the cylinder seals the air outlet of the air chamber and cuts off the negative pressure of the induced draft fan. Under control, the cloth bag is sprayed and cleaned. The falling off of the valve plate of the air chamber valve will cause the outlet air flow of the air chamber to be unable to be closed. The negative pressure of the induced draft fan operation and the positive pressure of the pulse solenoid valve through the blowing pipe to the dust collector bag are offset, resulting in the expansion and contraction of the filter cloth bag. When required, the filter cloth bag is not clean and the cleaning effect is poor. It is necessary to regularly open the uncovered cover of the gas chamber, check the valve plate of the gas chamber, check whether the valve plate is welded or deformed, and check whether the fastening nut of the valve plate is off, and tighten it in time.