Study On The Mechanism Of Being Blocked Of GGH In Power Plants

More than 50% of wet flue gas desulphurization system thermal power generating units set gas gas heater (GGH). In practical operation, GGH plug causes pressure increasing, leading to serious boosting fan stall, boiler trip; and affecting the safety of plant operation, economy and environmental benefits. For solving the congestion problems of GGH, the blocking mechanism of GGH, GGH scale composition, mist eliminator performance, the jet bubble reacter (JBR) control features and so on have been studied.First of all, it has been found that GGH scale is derived from the gypsum slurry carried by the net flue gas by analyzing phase and elemental of the GGH different side of the scale composition. Based on the power plants in Taishan and Dingzhou velocity field throughout the desulfurization system numerical simulation and experimental verification, it has been found that the velocity field before demister uneven distribution of flue gas velocity deviation from the best defogging efficiency demister area limestone slurry flue gas carried by leading to the increas GGH jam.The experiment of various parameters demister such as plate type, plate spacing, gas flow rate, effects on the efficiency demister has been performed, with arc-shaped plate and folded plate flue gas flow rate range of high defogging 4m/s～8m/s. The second brought in demister accurs when the fluegas flow rate is higher than 8m/s, leading the efficiency to a rapid decline. Two layout arc-Pack 26-20 combinations of blade Taishan power plant is more efficient than the average fog removing the original plate by about 8%; and three combinations with two demister combination have no significant improvement. Numerical simulation of demister shows that as the droplet diameter increases, the defogging efficiency increases rapidly. Folded plate demister fits for the separation of large droplets. Arc-shaped plate demister fits for the removal of tiny droplets. Droplets on the particle size of 20 microns or less are in the low efficiency of removal. JBR reactor experiment shows that:with the JBR run liquid level increases, the generation of small droplets remarkablely reduces; and the concentration of small droplets can be reduced by increasing the level of grid. In view of the actual operation of JBR 125mm, it's concluded that the best grid installation location is 50mm from the jet orifice department. On the basis of the mechanism, a technology of tiny droplets online test, desulfurization tower tiny droplets controling technology, demister plate coupled with the defogging efficiency technology, GGH heat exchanger cleaning technology and other key technology components have been developed. GGH plug of solution has been put forward, and the application in Taishan, Dingzhou and other large-scale thermal power plant engineering has got good results.