The Study On The Kinetics And Regeneration For FGD By Using Modified Semi-coke

In this paper, the semi-coke derived from lignite and bituminous coal produced in Erdos of Inner Mongolia was selected to prepare the SO2 desulfurizer of flue gas. To increase the desulfurizing activity of semi-coke, the series steps of modification methods was take measured. The raw semi-coke was modified by the technical steps of hydrothermal chemistry using autoclave, HNO3 activation, impregnation metal oxide on the surface of semi-coke and calcining at different atmospheres.The mechanism of the modified semi-coke desulfurizer was therioticaly analysted. The behavior of concentration of the modified active semi-coke catalyst was investigated in the fixed bed reactor under the conditions of atmosphere, the temperature range from 70℃to 100℃, and space velocity from 400h-1 to 2000h-1 in different size of particulates distribution. The intrinsic kinetics model was established in the form of the exponential function model. The equation is:, the activation energy is 10058.27J/mol and the pre-exponential factor is 69.62. The data will be used to design desulfurizing reactors. According to the component of the flue gas and the physical and chemical properties of the modified active semi-coke, the reactor was designed systemitcaly in term of the emission amount of the flue gas which emitted out by a boiler of 30t/h. The volume of the modified semi-coke packed bed was calculated to be 155.42 m3, and the area of the cross section of the bed was 18.47㎡, the height of the bed was 8.42m, respectivly. The velocity of the flue gas in the fixed bed under the temperature of the reaction was 0.9m/s. The paper also gives some suggestions of preventing corrosion for the reactor.The regeneration of desulfurizer with ammonia was considered to be an innovation that had many advantages, such as short generation time, generating entirely etc. The relation between the regeneration time and the concentration of (NH4)2SO4 was researched. In light of the series or shunt chemical technology of the regeneration with ammonia, the best washing order is obtained and the (NH4)2SO4 solution is condensed as possible as it could. The paper also gives some advice for the crystallization of the (NH4)2SO4 solution.Finally, the paper compared the methodology with other methods. After the comparison, the technique of the FGD by modified active semi-coke has a good prospect in the future and is worth promoting. The investment and the economic benefit for the process is calculated at the same time.