Study On Thermochemical Reaction Properties Of Benzene-containing Aqueous Solution And High-Temperature Coke

China has become the world’s largest coke producer,with an annual output of coke accounting for about 70%of the global coke output.The wastewater treatment volume brought by its coking industry is about 293 million tons.At present,most of them use a combination of biochemical technology and advanced treatment.The goal is to achieve zero or near-zero emissions.As we all know,coking wastewater contains toxic and harmful substances such as benzene,phenol,polycyclic aromatic hydrocarbons,etc.,which are difficult to degrade and have high treatment costs.Especially for independent coking enterprises,it will be more difficult to achieve zero discharge of wastewater.But at the same time,the organic aromatic hydrocarbons contained in wastewater can be utilized by thermochemical transformation.In this paper,a thermochemical method is used to use wastewater and hot coke from CDQ process as gasification raw materials to realize the resource utilization of wastewater to prepare syngas.This paper reviews the research progress of coking wastewater characteristics and coke thermochemical reaction at home and abroad.On this basis,the decomposition characteristics of benzene degradation,synthesis gas yield,and benzene gasification reaction in water during the thermochemical reaction between benzene-containing aqueous solution and coke are discussed in depth.Influence of the carbon microcrystalline structure of the coke matrix and its surface ash morphology during the process,etc.The gasification reaction characteristics of benzene-containing aqueous solution and coke at different reaction temperatures were studied for the first time.The results show that when the benzene concentration in water is constant,the higher the reaction temperature is,the larger the proportion of combustible gas in the synthesis gas;when the reaction temperature is 1000°C and the water vapor flow rate is 1 m L/min,increasing the concentration of benzene in the benzene-containing aqueous solution can promote the synthesis of benzene.Thermochemical reaction with coke and increase the yield of syngas.When the benzene concentration in water is 80mg/L,100mg/L and120mg/L,the proportion of H₂ in syngas increases by 6.4%,5.5%and 6.8%.CO increased by 12.87%,13.35%and 14.15%,while the calorific value of syngas increased by 16061 MJ/m³,39751 MJ/m³ and 71452 MJ/m³,respectively,on the basis of the original 190650 MJ/m³.With the increase of gasification temperature,the promotion effect of different concentrations of benzene-containing aqueous solution on coke steam gasification increased.In addition,through the study of reaction kinetics,it is concluded that the unreacted nucleation model can better describe the gasification reaction process in this experiment;when the benzene concentrations in the aqueous solution are 80mg/L,100 mg/L and 120 mg/L,respectively,the The apparent activation energy is reduced by 1.625k J/mol,4.038k J/mol and 4.39k J/mol on the basis of the original34.242 k J/mol.Through the preliminary experiments simulating CDQ conditions,it can be seen that with the increase of water flow into the furnace,the cooling rate in the furnace increases during the coke quenching process.When the concentration of benzene in water increased from 80mg/L to 100mg/L,and the flow rate of coke quenching water was 0.25m L/min,0.5m L/min and 1m L/min,the coke quenching time decreased by10min,3min and 4min respectively.The coke quenching rate increased with the increase of the benzene concentration in the coke quenching water,and the reaction rate constant and time dependence were obtained during the process,and the relationship between the carbon conversion rate of coke at different positions in the CDQ was obtained.In order to further explore the effect of benzene on the coke gasification reaction,XRD and Raman spectroscopy were used to characterize the coke performance at different stages of the reaction.From the 002 peak sub-peak fitting of XRD,it can be concluded that adding benzene in water can make the X_G peak ratio It is reduced by12.42%,and then it can be concluded from Raman spectrum that adding benzene to water can reduce the reduction of I_D4/I_G ratio,so that benzene in water can slow down the carbon structure graphitization formation process of coke.The analysis of the morphological characteristics of the coke surface by SEM shows that benzene in water can make the ash component that acts as a shield on the coke surface to form a pellet-like structure,thereby increasing the surface area of the coke reaction and improving its gasification reaction rate;the degradation rate of benzene was experimentally studied.The relationship between the reaction temperature and the benzene concentration in the benzene-containing aqueous solution,when the gasification reaction temperature is 1050°C,the benzene removal rate when the concentration of the benzene-containing aqueous solution is 80 mg/L,100 mg/L,120 mg/L,and 180mg/L,respectively 54.13%,59.53%,61.07%and 59.38%,respectively,indicating that the maximum benzene degradation rate can be achieved when the benzene concentration is 120 mg/L.Further through the gasification experiment of deashed coke with deionized water and benzene-containing aqueous solution,it was obtained that the average reaction rate was reduced by 0.336×10^-2min^-1 compared with that of non-deashed coke,and it was shown that the formation of benzene and ash components in water has the same effect.Morphology of organic structure,its catalytic degree of coke reaction is higher than that of inorganic ash.Therefore,the related research work is innovative.