Incineration Study On Organic Waste Liquid With Sodium Salts On Circlating Fluidized Bed

With the development of petroleum industry and chemical industry, production of organic waste liquid is increasing. Many cities in both developed and developing countries in the world are facing an important issue to find a suitable solution for the disposal of the expected large quantity of organic waste liquid. Organic waste liquid is formed during manufacture processing, and its disposal is, perhaps, one of the most complex problems facing the engineers in this field.Various methods of organic waste liquid disposal and its development trend in the world were introduced in the thesis. It was found that co-combustion of organic waste liquid and coal in a circulating fluidized bed (CFB) is a safe, economic and feasible way for organic waste liquid disposal.Systematic experiments on incineration of organic waste liquid with sodium salts using coal as auxillary fuel in a circulating fluidized bed test facility were conducted. The effects of some parameters, such as the flow rate of red waste liquid, the fraction of the red waste liquid sprayed in the dense bed of CFB, the secondary air rate and the excess air on the characteristics of combustion and emission of gaseous pollutants, in terms of NOx were verified. The experimental results show that under the experimental conditions, temperature in both the dense bed and the freeboard and combustion efficiency decreases as the flow rate of red waste liquid increases. When the fraction of the red waste liquid injected into dense bed increases temperature in the dense bed decreases and that in the freeboard increases, and the temperature distribution along the bed height becomes evener, the combustion efficiency first decreases and then increases. With increase in the excess air, temperature in both the dense bed and the freeboard decreases, combustion efficiency firstly increases and then declines. There is an optimum value corresponding to the highest combustion efficiency. For the fixed excess air, temperature in the dense bed decreases and that in the freeboard increases, temperature distribution becomes evener and combustion efficiency rises as the secondary air fraction increases. Because of suppressive effect of the low temperature and staged combustion on NOx in CFB, during all the experiments, NOx emissions were well below the national emission control regulation which is considered as a success of the experiment. NOx emissions increase with increase in the flow rate of red waste liquid sprayed, and decrease with increase in ratio of red waste liquid injected into dense bed. For the fixed excess air, NOx emissions decrease as the secondary air fraction increases. NOx emissions increase as the excess air increases.An analysis on melting characteristics was made based on the experiments with red waste liquid and coal. And the Radial Basis Function neural network was used to predict the fusing temperature of ash derived from combustion of red waste liquid and coal. The results have great significance for the design and operation of CFB boiler for incinerating organic waste liquid with sodium salts. Moreover, based on the thermal calculation, feasibility study of co-combustion of organic waste liquid and coal in the 20 t/h coal-fired CFB boiler was performed. The effects of the ratio of waste liquid to coal, the moisture in waste liquid and boiler output on the combustion characteristics, such as temperature profile, combustion efficiency and thermal efficiency were verified. The results lay rational foundation of waste liquid for CFB design.It is the first time to carry out the systematic experimental and theoretic research on incineration treatment of organic waste liquid with sodium salts in a circulating fluidized bed in the paper. The research findings provide solid basis for R&D of incineration technology of organic waste liquid...