Study On The Combustion Character Of Black Liquor From NSSC In Fluidized Bed

In recent years, accompanied with the rapid economic growth of China, problems of environmental pollution and shortage of resources are becoming more and more serious. One prominent problem of these is water pollution, especially the paper industry wastewater pollution which pollutes the most.As the most important method to produce Corrugated Medium, the black liquor of Neutral sulfite semi-chemical pulp (NSSC) has the characteristics of less organic matter and low heat valve. Therefore, cross-recovery or adding auxiliary fuel such as heavy oil are often used in the alkali recovery treatment of NSSC black liquor with cumbersome process, enormous investment and high recovery cost. According to the advantages of fluidized bed in dealing with the low calorific value pollution and based on many years foreign research experience of fluidized bed alkali recovery technology, this paper uses the fluidized bed incinerator to deal with NSSC pulp black liquor, instead of the traditional alkali recovery furnace. This method can not only reduce pollution effectively, but also low the investment and operating costs, which makes the alkali recovery technology more economic efficient in solving the pollution problem.The combustion characteristic of NSSC black liquor in fluidized bed is investigated in the paper. Under different temperatures between 600℃and 800℃, and different additives (calcium carbonate, kaolin, and calcium hydroxide)conditions, The combustion test of black liquor was carried out in a small bench-scale fluidized bed with sodium carbonate, sodium sulfate and mixture of sodium carbonate with sodium sulfate(mass proportion 1:3)as bed materials. The aim is to research the infection of fluidized bed agglomeration about alkali metals salt species in black liquor (solid matter 45%) and burning temperature. The research to the variety regulation of grain diameter of the bed materials were carried out at differdnt temperatures, too.Experimental results show that agglomeration can be avoided effectively by adding a little of low-cost additive at midium temperature.