In recent years, with rapid technological advances, environmental problems have been elevated to the level of law. Our scientists and technologists have developed some new desulphurization technologies, but most of them are still in the experimental stage and need further industrial application verification.
1. Sulfide alkali desulfurization method
Developed by the company Outokumpu sulfide alkali desulfurization method mainly uses industrial grade sodium sulfide as raw material to absorb SO2 industrial flue gas, the product to generate sulfur for the purpose. The reaction process is quite complex, with Na2SO4, Na2SO3, Na2S203, S, Na2Sx and other substances generated from the product can be seen higher energy consumption, and the low value of by-products, South China University of Science Shilin after the study showed that the process of sulfur Of the compound content changes with the reaction conditions change, the pH value of the solution is controlled between 5.5-6.5, adding a small amount of additive TFS oxidation, the product mainly produces Na2S203, filtered and evaporated to obtain high value-added 5H0? A2S203 ,, and desulfurization rate as high as 97%, the reaction process is: SO2Na2S = Na2S203S. This new desulfurization technology has passed the pilot, is promoting the application.
2 membrane absorption method
Membrane separation technology, represented by organic polymer membrane, is a new gas separation technology developed in recent years and has been widely used, especially in water purification and treatment. Jin Mei and other researchers at the Dalian Institute of Physics and Chemistry of the Chinese Academy of Sciences creatively use membranes to absorb and desorb SO2 gas, which has a remarkable effect with a desulfurization rate of 90%. The process is: they use polypropylene hollow fiber membrane absorber, NaOH solution as absorbent, the removal of SO2 gas, which is characterized by the use of porous membrane SO2 gas and NaOH gas absorption liquid separation, SO2 gas through the pores in the porous membrane to reach Gas-liquid interface, SO2 and NaOH react quickly to achieve the purpose of desulfurization. This method is a combination of membrane separation technology and absorption technology, a new technology, low energy consumption, simple operation, low investment.
3 microbial desulfurization technology
According to the microorganisms involved in the various processes of sulfur cycle, and access to energy characteristics, the use of microorganisms for flue gas desulfurization, the mechanism is: Under aerobic conditions, indirect oxidation of desulfurization bacteria, the flue gas SO2 oxidation of sulfuric acid The bacteria gain energy from it.
Biological desulfurization compared with the traditional chemical and physical desulfurization, the basic lack of high temperature, high pressure, external conditions such as catalysts, are operating at room temperature and pressure, and the process is simple, no secondary pollution. Abroad, geothermal power plants once a day 5t removal of H: S basis; calculate the total cost of microbial desulfurization is 50% of the conventional wet method. No matter for organic sulfur or inorganic sulfur, once burned can generate indirect use of inorganic sulfur by microorganisms SO2, therefore, the development of microbial flue gas desulfurization technology has great potential. Wang An, Sichuan University, who under laboratory conditions, the choice of ferrous bacteria for desulfurization research, at a lower liquid-gas ratio, desulfurization rate of 98%.
4. Thermal power plant flue gas desulfurization a new method - NADs ammonia fertilizer method
The ammonium solution is respectively reacted with sulfuric acid, nitric acid and phosphoric acid to obtain ammonium sulfate, ammonium nitrate and ammonium phosphate solution, and then is evaporated, crystallized and dried. To obtain a commercial fertilizer product; at the same time get 8% of a 0% (volume concentration) of s02 and air mixture, and then by catalytic oxidation (catalyst v: 05, si02), s02 into sq, and then concentrated sulfuric acid absorption, Concentration of 98.3% of the product concentrated sulfuric acid. It is noteworthy that, s02 oxidation sq is an exothermic reaction, that is, by-product steam. But in the existing foreign similar technology s4 + into s6 +, requires a lot of extra energy consumption. This is a prominent innovation in NADS technology.
Compared with the current similar ammonia method, NADS ammonia. Fertilizer has two prominent advantages: to ensure a high s02 absorption rate at the same time, the absorption tower outlet N in the gas concentration is low, less than 10mg / L, ammonia loss. NADS technology has developed a highly efficient so: absorption tower, the gas-liquid ratio is 30-100 times that of other technologies. Therefore, the absorption liquid circulation is very small, low energy consumption, to solve the technical problems of large desulfurization circulating pump. NADS technology uses a multi-stage absorber, equivalent to multiple absorber series, the industry is generally 3 to 5.
Absorption tower with the existing foreign limestone-gypsum method is different in ammonia. In the fat method, the absorbent NH is added from below the column instead of from the top. Add water to the top. Different from the traditional ammonia desulfurization, ammonia. Fertilizer mainly liquid ammonia (purity greater than 99%) as raw material, rather than ammonia as raw material. Therefore, in the ammoniac method, ammonia and water are separately added to the absorption tower.
Absorption tower is characterized by: from top to bottom, absorbing liquid mass concentration decreasing. Under normal circumstances, the lowest level of ammonium sulfite concentration in 30% of a 50%, depending on the quality of s02 gas imports may be. The highest concentration of ammonium sulphite absorption liquid is very low, basically less than 1%. Its advantage is to ensure SO: absorption rate greater than 95% at the same time, the export of exhaust gas NH, content can be controlled very low, less than 10mg / L. Therefore, ammonia. The monthly B method is very good at avoiding the "aerosol" problem of ammonium sulfite. In NADS absorption tower outlet exhaust, S02 mass concentration is always greater than NH3 mass concentration. Therefore, ammonium sulfite is present as NHI-ISO.
According to APCI's 70s patent, the necessary conditions for the formation of an ammonium sulfite aerosol are: PSO: PNH3KNH4HS04 The partial pressure is in mmHg and the temperature is Rankine. According to the operating conditions of NADS, the exhaust gas in the PSO: = 10010 a = 0.016mmng, PNH3 = 1010 = 0.0076mmHgPH20 = 12% = 91.2mmHg, can be considered to form a minimum aerosol temperature of 20, in fact, The temperature of 50 ~ 60 gas, higher than the patent literature recommended operating temperature 32 ~ 54. In addition, the exhaust gas into the reheater, the temperature will rise to 75 or more. Therefore, NADS technology is absolutely not the "aerosol" of ammonium sulphide. Absorption tower's internal components are mainly absorption sieve, separator and gas-liquid separation device.
Double Wire Fence is also called Double Wire Mesh Fence, which can be surface treated as Galvanized Double Wire Mesh and Powder Coating Double Wire Mesh.
The structure of the double wire fence is simple, and the material is less. Usually, the raw material is low-carbon steel wire, which is made of low-carbon steel wire after welding, and the mesh is rectangular.
The surface of the product can be galvanized or dipped in anti-corrosion treatment, and the bottom of the fence is integrated with the brick-concrete wall. This is for the rigidity of the mesh. Generally speaking, the service life can reach more than 10 years.
According to different use environments, the surface treatment of the mesh fence is also different. You can tell us your use environment, and Dongjie Wire Mesh's professional technical team will make a suitable recommendation for you.
Double Wire Fence,Double Wire Mesh Fence,Galvanized Double Wire Mesh,Powder Coating Double Wire Mesh
Anping County Dongjie Wiremesh Products Co., Ltd. , https://www.dongjiewire.com