The Research On Slurry Ability And Combustion Characteristics Of Indonesia Lignite CWS

Recently, the global hot spot is the pollution to the environment of the comprehensive utilization of coal. Clean coal combustion technology is the key projects in national scientific and technological research, and the coal-water-slurry (CWS) technology is an important branch. The low rank coals, represented by the lignite, are very abundant and have lower cost in both mining and marketing However, the concentration of lignite CWS is very low because of the lower level of coal rank and the higher internal water content, limiting the promotion of CWS technology to some degree. Therefore, studying the slurry characteristics of lignite is the precondition of large scale industrial application.In this paper, a series of work were performed under the slurry ability around Indonesia lignite by using the single additives (NDF, MF, MC and MT) and mixed surfactant (Y+SA, M+Y, MF+02, M+MF, M+02and Y+02). The test results showed that Y+02were best fit for Indonesia lignite slurry while the coal concentration was51.13%. XPS analysis found that the surface of lignite coal rich in polar oxygen groups, such as-COOH and-OH. Besides the coal has developed pore structure, resulting in internal water content as high as17.15%. These are the root cause of the poor slurry ability of Indonesia lignite.Chemical surface modification was also investigated in the paper. The contact angle increased greatly after the coal powder was wrapped by the coal tar oil. The coal concentration, using processed coal powder, also increased from51.13%to54.10%. It was the modifying agent wrapped on the surface of the pulverized coal that functioned so as to increase the adsorption layer of additives.Finally, the Indonesia lignite CWS was conducted on the cylinder horizontal furnace to test the thermal performance. Some regular results have been gained by analyzing the distribution of temperature field in the furnace, the particle microstructure along the furnace, the slagging characteristics and pollutant emissions. The slagging process has been investigated by using silicon carbide rod. And the ash sediment of CWS was explored by means of XRD and SEM. According to fuzzy comprehensive evaluation method, with the high resolution and slagging index for factor set (alkali/acid ratio B/A, silica/alumina ratio, G, slagging comprehensive evaluation R), we can infer that the combustion in the furnace belongs to medium slag, which was consistent with experimental result.