In our country, with the economic and production development, the environmental pollution was also increased. China's environmental quality has become more prominent. Especially in the power industry and industrial enterprises, as well as heating, such as the North China caused by coal burning pollution is worsening. Pollution is such that need to be solved. The large capacity industrial boilers and small and medium-sized power plant boiler contaminated seriously almost without SO2 pollution control measures. The discharged total quantity of SO2 is over the limits, it's urgent to make research and development on SO2 pollution control technology, so that SO2 pollution control to meet emission standards. All of our technical storage on the work of national research for years and learning of advanced desulfurization technology at home and abroad, we put the desulfurization technology into different kinds of boiler in special purpose rig test integrate with practical application. We study on the coal kind that was used and desulfurizer characteristics to find out its rule. We work on prior period technical problems on limestone injection desulfurization test of small boilers, improve on combustion condition to meet the desired objectives that could reach the all devotion for industry application. Key technology: the sulfur fixed in furnace of CFB boiler, that means the adsorbent break down to fix the sulfur in furnace, and the limestone powder sends to dense phase area of furnace by air. The calcium carbonate was heated and breaks down into calcium oxide and carbon dioxide immediately.
CaCO3→CaO＋CO2↑ CaO+SO2+1/2O2→CaSO4 CaO+SO3→CaSO4

Then we adopt the steam return activation technology, that means the steam make a chemical with sintered CaO to Ca(OH)2, and enter the furnace to take a chemical with SO2, it will substantial increase in desulfurization rate in system.
CaO+H2O→Ca(OH)2 CaSO3+1/2O2→CaSO4

Innovations: firstly, the limestone powder aerodynamic field will be optimized, include the situation, angle and speed of jet to make mix fully so that improve the desulfurization efficiency. Secondly, that is the steam return, it means that ash from high temperature separator on boiler exit and desulfurizer return to furnace by steam so that carry out the circulation. Meanwhile, the steam take a chemical reaction with Cao to Ca (OH)2, and enter the furnace and take a chemical reaction with SO2. That could improve the efficiency of desulfurization greatly. This technology has simple process, low equipment cost, low operating costs, compact, no secondary pollution and low technical management level request. This is the most suitable CFB boiler flue gas desulfurization technology for China's conditions. We have got the national new product certificate. We have accumulated a large number test data in trying to find out the test method and research. We made a breakthrough on key technologies: the application on small boiler shows that the steam return make the system get 90% efficiency, and reached the leading domestic level: 75t/h CFB boiler of Heihe Thermal Power Plant, Neimenggu Shiyao Thermal Power Plant and other 75t/h boiler achieve application success with vast Industrialization foreground. National major development production certificate number: 2003ED671018.