Transformation And Analysis Of Coking Process Pollution Based On Dynamic Simulation

In recent years,coke production in China has always been the highest in the world,and at the same time,it is also a typical high-pollution industry.With the new normal of China's economy and the implementation of the new environmental protection law in 2015,it put forward more stringent environment requirement and supply side reform for the coking and steel industry.In order to analyze the characteristics of the production process of coking enterprises and to analyze the migration and transformation rules of nitrogen and sulfur elements,a static and dynamic analysis method suitable for the actual coking production system is established,which combines the mechanism simulation with the process simulation.Main contents and innovations are as follows:(1)Based on the traditional material flow analysis method.According to the characteristics of coking industry,the analysis frame of static material flow is set up with the geographical area of coking production as the system boundary,and the index of key flow,key node fluctuation and conversion efficiency are established to analyze the static material flow and the fluctuation of different working conditions.On this basis,a dynamic material flow analysis framework which combines the mechanism simulation with the process simulation is established.The pyrolysis process of the core coke oven through the mechanism is simulated.The CPD model is extended and applied to the actual coke oven pyrolysis process and Aspen Plus to realize the dynamic modeling of the whole coking process.(2)Relying on static material flow analysis method,it is applied to case enterprises.When the annual production of coke is 1 million tons,the coal input of coking production system is 135 million tons.The carbon element accounted for 75.4%of the input,and most of it was outputted as coke product.The nitrogen element accounted for 1.4%of the input,and most of it was outputted as coke and ammonium sulfate products.The sulfur element accounted for 0.5%of the input.The biggest difference of nitrogen and sulfur conversion efficiency can be 9%.The results of static element flow analysis show that the nitrogen and sulfur elements fluctuate greatly under different working conditions,and the core conversion is concentrated in the coke oven.It is necessary to simulate it dynamically.(3)Relying on dynamic material flow analysis method.The simulation of coke oven shows that the yield of coke,tar and gas is different under different coal blending ratio.Assuming that the ratio of HCN and NH3 is 3:1,the CPD model can be extended,which can be used to simulate the release of nitrogen in the coking process.It is assumed that the organic sulfur cleaves to produce H2S and the pyrite sulfur cleaves to produce COS.It issimilar to the release of nitrogen in the original CPD model.The first order rate equation and the distributed activation energy can be used to describe the release of sulfur in coal.The content of H2S and COS in the raw coal gas under different coal rank can be simulated.