The calcium injection desulphurization technology is a desulphurization method in which the desulfurizer is directly blown into the furnace and reacts with SO2 in the combustion gas. In this paper, the desulfurization problem of pulverized coal furnace and circulating fluidized bed furnace in power plant is discussed deeply. The best desulfurizer is limestone calcium powder, which can be injected into the furnace to enhance its reactivity and improve the desulfurization efficiency. The important equipment of limestone powder blowing is the material powder conveying pump , which can also be called "calcium desulfurization pump in furnace". The equipment is suitable for all kinds of powdery materials, especially limestone powder and fly ash, and the conveying efficiency is very good.
[Reaction mechanism of calcium desulfurization]
Calcium injection in the furnace is to directly inject dry calcium powder into the boiler furnace, and the heat in the furnace will calcination calcium powder into active CaO so as to react with the SO2 in the flue gas to achieve the purpose of desulfurization.
The reaction mechanism of calcium injection desulfurization is still calcium-based desulfurization principle. Limestone is first calcined at a rapid rate above 800℃ to form calcium oxide, and then CaO meets SO2 in the temperature range of 800~1200 for direct desulfurization reaction to produce CaSO4.
When dolomite [CaMg (CO3) 2] is used as desulfurizer or limestone contains MgCO3, the following reactions will also occur:
  
 

During the reaction, when CaCO3 particles are transformed into CaO particles, the molar volume of cacO3 particles is reduced by about 45%, and the void in the particles is enlarged, which is conducive to the desulfurization reaction and the formation of CaSO4. But with the formation of CaSO4 its molar volume increases by about 180%. Therefore, SO2 reacts on the surface of desulfurizer and in large voids at the initial stage of reaction, and the chemical reaction rate is the main control resistance. With the consumption of calcium base, the generated dense CaSO4 will prevent SO2 from entering the internal voids. At this time, the surface volume diffusion resistance and internal diffusion resistance gradually become the main influencing factors.
Fly ash after desulfurization is also better recycling, fly ash contains a large number of spherical particles with good particle shape, high strength, low density and other advantages, can be widely used in metallurgical building materials and other fields. Dry desulphurization process is carried out in a completely dry state without liquid phase intervention. With the increasing perfection of dry desulphurization process, coupled with the factors of simple process, low investment and low operating cost, dry desulphurization process has been popularized and applied in coal-fired power plants.
As an advanced enterprise with more than 10 years of production and research and development experience in Henan, innovation machinery through the continuous introduction of foreign advanced technology, relying on its own advantages, the product is very scientific and technological innovation and product research and development, and has successfully developed a variety of patented products. The material powder conveying pump is undoubtedly the preferred transport equipment for calcium desulfurization system in the furnace.