The Study On Key Factors Of Regenerative Thermal Oxidizer In Treament Of Volatile Organic Gas

Volatile organic compounds?VOCs?,abbreviated as VOCs,are mostly poisonous and harmful odorous substances.They are also important precursors for the formation of PM_2.5 and ozone.Industrial sources are their major sources of emissions.More than 300VOCs have been identified so far,which makes VOCs difficult to manage.The Regenerative Thermal Oxidizer?RTO?is a device for processing VOCs.China's RTO is widely used,but most of them are based on empirical design and lack of reference.Besides,the current simulation research cannot catch up with the rapid development of VOCs processing,and the depth of research was not enough.The simulation study has the advantages of low cost and high accuracy.Therefore,the RTO simulation study can provide reference for industrial design and has very practical significance.First of all,this paper simulates the cold state of RTO.Select the appropriate cold simulation models,analyze the cold flow field inside the RTO.The results of the study show that the gas flow directly affected the RTO internal velocity distribution and exhaust gas composition distribution.There were vortices in the velocity of the gas inlet area.The velocity and component concentrations were evenly distributed in the regenerator chambers and oxidation chambers.Secondly,industrial experiments are conducted to study RTO and verify the correctness of the hot simulation model.Collect data of RTO during operation,analyze the internal temperature changes of RTO during the warm-up state and stable operation state,and provide data reference for hot simulation calculation.Select suitable hot simulation models,calculate multiple cycles,and compare it with experimental data.The results show that the RTO oxidation chamber temperature and the packed beds temperature both showed small amplitude fluctuations with obvious periodic variations under hot conditions.The error between the simulated value and the experimental value in each period of the RTO simulation model was very small,the average error in multiple cycles was less than 3%,so that the simulation model can be used to calculate the RTO.Then,analyze the influence of air volume,VOCs concentration,valve switching time,and purge volume on RTO.The results show the air volume had a great influence on the RTO.Under different air volume,the temperature of the oxidation chamber and the packed beds changed periodically during multiple periods,but the average temperature remains basically unchanged.VOCs concentration had little effect on packed beds temperature and outlet temperature,and VOCs concentration mainly affected oxidation chamber temperature.The longer the valve switching time,the more severe the gas temperature changed in the oxidation chamber and regenerator chamber.When the purge volume was larger,the amount of VOCs remaining in the regenerator chamber were smaller and the thermal efficiency was higher.Finally,comprehensively analyze the impact of several factors on RTO.Using orthogonal experimental method to study the influence of various factors on RTO,and through the range analysis,obtain the optimum conditions of RTO in this paper.The variables affecting the temperature of the oxidation chamber and the average outlet are screened by the standardized regression coefficients,and eliminate the variables with small influence.Finally,obtain the formulas for calculating the temperature of the oxidation chamber and the average outlet temperature through regression analysis.The results show that the valve switching time had the greatest effect on the oxidation chamber temperature and its uniformity,and the empty chamber flow rate had the greatest effect on the average outlet temperature.The overall relationship between the regression model and the selected variables was significant.The residual values were mostly close to zero and contain zero points.