I. Overview
Power plants, thermal power plants and large boilers use wet desulphurization to produce a large number of sulfur gypsum, desulfurized sulfur gypsum by filter filter, surface water content in 10 ~ 15%, particle size distribution of 10 ~ 100μm, calcium sulfate content is generally more than 90% ~ 95%.
Various experiments show that high quality building gypsum powder can be produced by drying and calcining desulphurized gypsum. Because the production of hemihydrous gypsum with desulphurized gypsum is still in the beginning, the construction materials of the sulfur gypsum calcination have no special drying production equipment at present, the production of sulfur gypsum with natural gypsum equipment has great differences in the technology. A domestic company introduced foreign equipment to quickly calcined sulfur gypsum to produce building materials gypsum, at present there are still technical problems in the use of continuous improvement and adjustment. Beijing Xingda Kaiyuan Desulphurized Gypsum Co., Ltd. adopts the "Schede Calcining furnace" designed and manufactured by Liaoning Dongda Powder Engineering Technology Co., Ltd. for the production of building gypsum powder by calcining sulfur gypsum. In April 2006, it began to debug and put into production. During the debugging process, a reasonable calcining process system was developed according to the characteristics of sulfur gypsum. The semi-hydrous gypsum produced conforms to (GB9776-88) standard and reaches and exceeds the performance of superior products. The successful application of the calcining furnace in the calcining of thiougypsum provides advanced and reliable process data and equipment for the production of building gypsum from thiougypsum.
2. Technological process and basic principle of sulfur gypsum calcination
According to the above-mentioned calcining system technology, the system equipment is mainly composed of heat source, Sider calcining furnace, gas-solid separator, Chen bin and storage bin.
Sid calcining furnace is the main equipment in the above system. Sid calcining furnace is a kind of fast calcining equipment. Its main structure is composed of mechanical dispersing mechanism, gas distribution chamber, dry calcining chamber and centrifugal homogenizer. The hot air heated by the combustion chamber enters the gas distribution chamber of the Sider calcining furnace, and the material to be calcined is sent by the feeder into the Sider furnace. Through the mechanical dispersion arranged at the bottom of the furnace and the rotating air movement generated by entering the furnace through the gas distribution chamber, the material is quickly dispersed and a large specific surface is formed. The heat carrier is quickly heat transferred with the material, and the dry calcining process is instantly completed.
This system uses coal as the fuel on the heat source and adopts the machine-fired coal flue gas hot blast stove. The high temperature flue gas generated by combustion is directly used as the heat source for drying and calcining after dust removal treatment.
The process of calcining sulfur gypsum by Sid calcining furnace is as follows: The sulfur gypsum is sent to the feeder of Sider calcining furnace by lifting conveyer and enters the calcining furnace. The mechanical dispersion in the calcining furnace and the high temperature flue gas generated by the heat source enters the calcining furnace for rapid heat transfer with the dispersed sulfur gypsum. The surface water of the sulfur gypsum is quickly vaporized in the drying section, and the material temperature rises rapidly into the calcining section. After 5 ~ 10 seconds of drying calcination process is completed. The gypsum powder transformed into semi-water enters the gas-solid separator at the exit of Side calcining furnace for gas-solid separation. The collected semi-water gypsum is sent to the Chenhua warehouse by conveyor, and the tail gas is further purified and discharged into the atmosphere by bag-type dust removal.
Iii. Main characteristics and process data of Sider calciners
It is necessary to combine the operation process of the calcining furnace with the calcining process of the sulfur gypsum to determine the basic operating rules by using the Sider calcining furnace. In the process of debugging, by adjusting the inlet and outlet temperature of Sider calciners, adjusting the feed speed of materials in the system and the interface factors between drying and calcining, the relevant conditions affecting the initial and final coagulation, compressive resistance and bending resistance are found out, and the basic operating procedures are determined. The following data is related to the results reflected in the debugging.
(See table) sample test table