Preparation Of Blue Coke Water Slurry By Blue-Coke And Assessment Of Its Combustion Performance

This paper prepared a new-type clean fuel- blue coke water slurry, which use bluecoke as raw material. In the areas of energy-saving emission reduction and industrial chain extension, the fuel has a great significance for the technology upgrading of high energy consumption and high pollution industry, as coal processing or metallurgy.The influence of viscosity, fluidity and stability of the particle size distribution, additives types and the ambient temperature had been mainly studied to determine the best preparation process and technical parameters. Using thermol gravimetric analysis and Aspen plus simulation to analysis and evaluate the combustion process and the combustion performance.Studies show that the additives types and particle size distribution were important factors for the concentration, viscosity and stability of the blue coke water slurry. After combination of Sodium Lignosulfonate(SL) and Polycarboxylate(PC), the SL can offset the defect of PC’s poor adsorption on the condensation of aromatic ring body of bluecoke surface, and make PC adsorb on the coking aromatic core easily. Using the compound dispersant can make a great synergistic increase for the dispersion and stability. The best addition of SL-PC is 1.0wt%, and the optimal ratio is SL: PC=2:1, under this condition the slurry concentration can reach 65.5%. Through analysis of blue-coke partical size distribution,Screen Classification can make the concentration of the blue coke water slurry reach 64.57% from 63.53% in the best particle ratio as M<45um : M45μm~74um : M74μm~125um : M125μm~250um = 5:2:2:1. In the same grinding time, the concentration of water slurry prepared by Grinding Classification is not as high as Screen Classification, but through extending the grinding time it can reach higher concentration 66.76%. High temperature and excessive stirring have a bad effect on the preparing of blue coke water slurry. Proper temperature, stirring time and stirring speed were the key conditions for preparing high concentration water slurry.The optimum conditions of blue coke water slurry preparation were grinding classification of 750 s, the compound dispersant of SL-PC(dose of 1.0wt%,combination rate of SL:NSF=2:1), stabilizer of CMC(dose of 0.02wt%), temperature of 25℃, stirring speed of 800 r / min, stirring time of 10 min, respectively. Under this condition, the maximum concentration is 66.02%, the apparent viscosity is 911.02 mPa.s, the fluidity time is 49 s, the syneres rate is 0.56%.The analysis of the blue coke water slurry TG-DTG and DSC showed that, the combustion process could divide into three stages: water evaporation, volatilization of combustion and common combustion of the char and volatile.The blue coke water slurry still have the disadvantages as low heat value, combustion lag and poor stability of burning when compared with the coal water slurry. The results of Aspen Plus simulation show that, when the simulation feed flow rate is: blue-coke 1000kg/hr, water 538kg/hr, air 9000kg/hr, the temperature of the combustion furnace BURN can reach to 1502.41℃,the heat release can reach to 11886MJ/hr. The combusion process of blue coke water slurry has the advantage of high-efficiency(96.46%), low emissions of polluting gases(NO+NO2+SO2+SO3=0.52wt%), less dust content(0.013kg/hr) and smalle partical size(0.32μm~0.61μm), it would be a kind of clean and efficient environment-friendly fuel, in addition, the price of blue coke water slurry is poor, so blue coke water slurry has a good promising prospect and is worth in further research and wide use.