In metallurgy, machinery, chemical industry, electric power and other industries, the exhaust gas emitted from various industrial furnaces is not only with high temperature, but also contains a lot of dust and harmful gases, which is one of the main factors causing environmental pollution. Under the condition of high temperature, because the viscosity of exhaust gas changes greatly, the humidity drops greatly, the fine particle condensation phenomenon is greatly reduced, so it is difficult to separate particles. The bag-type dust remover cannot withstand the high temperature of the exhaust gas, and the wet de-dusting cannot be utilized comprehensively. Electrostatic Precipitator also has a high investment, covers a large area and insulation problems. At present, high temperature industrial dust-containing waste gas treatment method in our country is mostly through water condensation, makes the high temperature exhaust gas drops to 200℃, then uses the bag duster to remove dust, this not only increases the condensation equipment investment and the operating expense, also causes the massive heat energy loss.
High temperature exhaust gas dust removal has the following characteristics:
(1) The required dust gas temperature is high, up to 600~1400℃.
(2) The dust particles in exhaust gas are fine, usually <5~10μm in diameter, even in sub micron scale.
(3) High purification standards, export concentration requirements of 10~50mg/m3, or even smaller.
There are nearly 200 thousand industrial kilns in our country, the annual consumption of coal (coke) is about 200 million tons, and a large amount of high temperature dust and harmful gases are emitted in the production process, which seriously pollute the atmospheric environment. The exhaust emissions are characterized with high temperature, high dust concentration, large blackness, and wide variation of temperature, flue gas volume. With the development of economy, environmental protection requirements are becoming stricter. Therefore, the new high temperature industrial waste gas dust removal technology is an important issue to be developed urgently.
Since 1970s, the advanced countries in the world have been studying the ceramic membrane filter dust collector with various materials and structures, which has been used for high temperature filtration and dust removal, and has achieved good results. The main physical properties of ceramic membranes are porosity, permeability and bending strength. The results show that compared with other types of dust, dust removal efficiency of ceramic membrane filtration dust collector is high, can reach more than 99.99%, the particles with size more than 5μm can be removed, and has the advantages of simple structure, the most important is the high temperature resistance, the working temperature can reach above 800℃, and has good corrosion resistance in oxidation and reduction in a high temperature environment, so the ceramic filter dust collector in high temperature dust play an important role.
Based on the filtration performance of ceramic membrane, a variety of filtration devices can be developed, and the main applications are summarized as follows:
(1) Dust removal device of ceramic filter in coal-fired power plant. This is considered to be one of the most credible dust removal techniques. In view of the strengthening of environmental awareness, the current electrostatic precipitator usually used in coal-fired power plants will be difficult to meet the requirements of environmental legislation.
(2) Dust collector for ceramic membrane filter in metallurgical industry. In nonferrous metal smelting, the drying of concentrate and leaching slag is widely used in rotary kiln. Drying kiln produces a lot of soot; containing metal particles pollute the environment. Because the temperature of flue gas and its dew point temperature (45~65℃) is very close, and it absorbs humidity, it is easy to cause the condensation of flue gas, which brings difficulty to dust collection. The above problems can be solved well by using ceramic membrane filter to collect dust at high temperature.
(3) New clean coal combustion technology - integrated gasification combined cycle power generation (IGCC) route, is a new type of high efficiency power generation technology which is invested and developed all over the world. It will be practical in twenty-first Century. After the coal gasification reaction tower and the desulfurization device, the high temperature gas dust is filtered out, and the ceramic membrane filter is the best technical route.
(4) Industrial gas purification, especially high temperature flue gas and gas chemical industry, including the removal of solid particles in the industrial process of raw material gas and solid particles in the exhaust gas purification, removal, directly related to the service life and operation safety of downstream equipment, these industrial furnace kiln flue gas in the dust (particles less than 10 µm), will endanger human health. For the above processing requirements, ordinary dust collector is difficult to achieve, but it is the advantage for inorganic ceramic membrane filter.
(5) Recover of useful powders, especially high added value dust. For example, in the petrochemical plant fluidized bed equipment to recover catalyst, to collect powder in the air transport and spray drying process, Nano material production and other ultrafine powder production in the recovery of powder.
(6) With the improvement of environmental protection requirements, in order to protect human health, such as waste incineration, especially radioactive, infectious and other harmful waste, such as medical and other waste incineration, in order to prevent harmful dust pollute the atmosphere, the use of high efficiency ceramic membrane dust removal is a practical method.
Tel:+86 592 6514970