Study Of The Properties Of Coal-sludge Slurry

With the rapid development of the world industry and the sharp increase of urban population, the requirement of water resource is growing, sewage treatment has become the urgent problem in the world today. As the by-product of wastewater treatment, sludge production are also increasing rapidly, however, most of them are not properly handled, which brings great harm on the environment. At present land application, landfill, incineration and resource comprehensive utilization are the main four sewage sludge disposal methods, in which the resource utilization is the ultimate direction and goal of the sludge disposal.The pipeline transport of sludge can effectively prevent the secondary pollution due to its whole sealing, but the sludge’s high viscosity has limited its application。In this work the dewatered sludge produced by Jiangxinzhou sewage treatment plant was selected for the research first to study how to effectively improve the liquidity of the sludge; The results showed that by high speed mixing the sludge can greatly reduce its viscosity, on this basis, by means of adjusting the PH value of the sludge, joining different kinds of varying amount dispersants and raising the temperature appropriately can effectively lower the viscosity of the sludge, what’s more the naphthalene sulfonate formaldehyde condensation dispersant compounded with sodium hexametaphosphate dispersant can better reduce the sludge viscosity, and good fluidity of sludge was obtained.In the second part of this work two different dewatered sludge from Jiangxinzhou sewage and Yangzi petrochemical treatment plant firstly were modified by NaOH pretreatment, and then were mixed in the Yanzhou coal with different ratio to jointly prepare coal-sludge slurry(CSS) via wet ball grinding, the obtained CSS were tested in various performance. Experiments show that the addition of sludge has a big improvement effect on wet ball grinding efficiency, the prepared CSS has good rheological properties, and stability is well improved; With the5%～10%sludge adding proportion, the concentration are more than60%. All the CSS have little change in combustion heat, ash fusion temperatures, mixing characteristics, aging characteristics, viscosity-temperature characteristics etc., so that the CSSs can meet the demand of industry application and well solve the problem of low caloric and high moisture of sludge. Furthermore, by the adsorption of coal particles, it can greatly reduce the sludge’s odor, which reduce the inconvenience of sludge disposal.In a comprehensive consideration of various conditions, for Yanzhou coal, with0.8%naphthalene sulfonate formaldehyde condensation dispersant of dry coal and using wet ball grinding process,5%-10%addition proportion of two kinds of sludge is a suitable range. The various aspects of performance of the obtained CSSs can reach requirements of industrial applications. The CSS technology is a promising way for the sludge resource utilization.