Experiment Studies On Drying And Incineration Integration Technology Of Municipal Sewage Sludge

Due to the ever-increasing amount of sewage sludge and more stringent environmental quality standards,the treatment and disposal of sewage sludge becomes an expensive and environmentally sensitive worldwide problem.Especially the disposal of municipal sewage sludge has become the bottleneck of the industry of municipal sewage treatment.Experimental research on integrated drying and incineration of wet municipal sewage sludge in a fluidized bed was made.The investigation on adjusting a pneumatic distribution valve,drying wet municipal sewage sludge in a fluidized bed dryer and analyzing emissions were made on a 0.15 MWt circulating fluidized bed.Cold tests on a classifier of coarse particle and fly ash were also accomplished.The experiment of governing pneumatic distribution valve was under condition of not feeding sewage sludge into the test-bed and feeding it into the test-bed.The regulating method was obtained.The fluidization velocity is a key parameter to keep the fluidized bed dryer stable running.After drying,the moisture of sludge pellets decrease to 20%and the average diameter is 250μm.The emissions of SO₂ and HCl are relatively high when municipal sewage sludge is incinerated.According to the difference of terminal drop velocities between coarse and fine particles,a cold fluidization rig was made for experiments on the separation of binary particles of sands and fly ash.Main influence parameters of separating air velocity,solid-air ratio,fly ash ratio and particle size on the separation efficiency and sand escaping ratio are analyzed.The separation efficiency increases with the increasing of the separating air velocity,decreases with the increasing of the solid-air ratio and the fly ash concentration.Based on the experimental study,a boundary of operation parameters of high efficiency separation is obtained for engineering design.