The desulfurization technology of magnesium oxide is a kind of promising desulphurization technology, which is more mature, less investment, simple structure, good safety performance, and can reduce secondary pollution, desulphurization recycle, reduce desulfurization cost, Of the economic benefits. Relative to the calcium desulfurization, to avoid the simple wet there are a series of problems, such as pipe plugging, low smoke temperature, flue gas with water and the presence of secondary water pollution, etc .; at the same time with the more complete limestone / Gypsum method, covers an area of small, low operating costs, a substantial reduction in investment, comprehensive economic benefits have been greatly improved.
Magnesium oxide desulfurization technology is a mature degree of calcium desulfurization process after the technology, magnesium oxide desulfurization process around the world have a lot of application performance, which has been applied in more than 100 projects in Taiwan, 95% of the power station is Magnesium oxide method, the other in the United States, Germany and other places have been applied, and in some parts of our country has been the application of performance.
Magnesium oxide reserves in China is very impressive, has been proven magnesium oxide reserves of about 16 billion tons, accounting for about 80% of the world. The resources are mainly distributed in Liaoning, Shandong, Sichuan, Hebei and other provinces, of which Liaoning accounted for 84.7% of the total, followed by Shandong Laizhou, accounting for 10% of the total, the other mainly in HebeiXingtai River, Sichuan GanLuo Yan Dai, Hanyuan, Gansu Subei, do not cover and other places. So magnesium oxide can be fully used as desulfurization agent in the power plant desulfurization system to go.
In terms of chemical reactivity, the magnesia is much larger than the calcium-based desulfurizer, and because the molecular weight of magnesium oxide is smaller than that of calcium carbonate and calcium oxide. So the other conditions are the same circumstances, the desulfurization efficiency of magnesium oxide is higher than the desulfurization efficiency of calcium method. Under normal circumstances, the desulfurization efficiency of magnesium oxide can reach more than 95 ~ 98%, while the limestone / gypsum desulfurization efficiency of only about 90 ~ 95%.
As the desulfurization of magnesium oxide itself has its own unique advantages, so the absorption tower structure design, circulating slurry size, the overall size of the system, the power of equipment can be relatively small, so that the entire desulfurization system investment The cost can be reduced by more than 20%.
The main factors determining the operation cost of the desulphurization system are the consumption cost of the desulfurizing agent and the consumption cost of the water and electricity steam. Magnesium oxide prices higher than the price of calcium oxide, but the removal of the same amount of SO2 magnesium oxide is 40% of calcium carbonate; water and electricity and other power consumption, the liquid to gas ratio is a very important factor, it is directly related to The desulphurization efficiency of the whole system and the running cost of the system. On the limestone gypsum system, the liquid-gas ratio is generally more than 15L / m3, and magnesium oxide in the 5L / m3 below, so magnesium oxide desulfurization process can save a large part of the cost. While the sale of magnesium oxide by-product can offset a large part of the cost.
Magnesium desulfurization relative to the biggest advantage of calcium method is the system does not occur scaling fouling equipment problems, to ensure safe and effective operation of the entire desulfurization system, while the PH value of magnesium control in between 6.0 to 6.5, in this condition Equipment corrosion has also been a certain degree of solution. In general, magnesium desulfurization in the actual project safety performance has a very strong guarantee.
As magnesium reaction desulfurization reaction product is magnesium sulfite and magnesium sulfate, the comprehensive utilization of high value. On the one hand, we can forcibly oxidize all the production of magnesium sulfate, and then after enrichment, purification and production of magnesium sulfate heptahydrate for sale, on the other hand can also be directly calcined to produce high purity sulfur dioxide gas to produce sulfuric acid.
We know that sulfuric acid is known as the "mother of the chemical industry," sulfur dioxide is the raw material for the production of sulfuric acid. China is a relative lack of sulfur resources in the country, the annual imports of sulfur more than 5 million tons, equivalent to 7.5 million tons of sulfur dioxide. In addition magnesium sulfate in food, chemicals, medicine, agriculture and many other applications are relatively wide, the market demand is relatively large. Magnesium desulfurization full use of existing resources to promote the development of circular economy.
Common wet process desulfurization process, there is the inevitable secondary pollution problems. For the magnesium oxide desulfurization technology, the subsequent treatment is more perfect, the regeneration of SO2, to solve the problem of secondary pollution.