Application Study Of Regenerative Thermal Oxidation In Treatment Of The Organic Waste Gas In Nbr Production

With the rapid growth of petrochemical industry during these years,the pollution problem became more and more severe,and the public are paying more and more attention to the environmental issues in the petrochemical industry.In the process of NBR production,there are large amounts of volatile organic compounds,such as unreacted raw materials acrylonitrile and butadiene,most of which are toxic and harmful to the environment.If these VOCs are directly released into the air,they are not only harmful to the air quality,but also affect the growth of plants and animals,and threat the human health.In April 16^th 2015,the government published GB31571-2015?Emission standard of pollutants for petroleum chemistry industry?,which indicates the decree of the GB16297-1996 expired in the meantime.The new standard points out the existed enterprise should implement the new specifications of emissions.However,the methods of direct flare combustion and bio-trickling filter in Nantex could not meet the new requirement,so the company is taking the risk of production suspension and rectification.Therefore,it has important practical significance and strong application values to study how to treat the waste gas produced from the production line of NBR thoroughly to conform to the GB31571-2015?Emission standard of pollutants for petroleum chemistry industry?.To solve the problem of non-compliance emission of NBR waste gas,we studied features and effects of different techniques on the removal of VOCs at home and abroad,and learned the experiences from the peers.Among these treatments,the regenerative thermal oxidizer technology was selected as the new method to treat the VOCs produced in the production process of NBR.The main tasks of this paper are as follows:1?The parameters of RTO system were designed and the system was tested.In order to attain higher VOCs destructive removal rate and to assure the zero malfunction rate,the five chamber RTO system is introduced to treat the waste gas from the NBR production line.Trough calculating,the LEL of the mixing gas,the volume of ceramics,the scale of the regenerative thermal chamber,the combustion chamber,and the gas-collecting chamber were set.Also,the heat balance was analyzed.The pipeline system was designed,and the total resistance loss was calculated to determine the fan model.The designed RTO system was installed and tested.2?Optimized the RTO operation system.We summarized the features and efficiency trend of RTO on the removal rate of VOCs and the thermal recovery rate,with the change of the three different following conditions,the temperature of the reaction chamber,the retention time of the VOCs,and the inlet concentration of the VOCs.The investigation shows:the reaction temperature is the key factor of the VOCs destructive removal rate.To keep the high DRE of VOCs,it is necessary to set the reaction temperature over 700?.The reaction temperature does not much affect the thermal recovery rate.The change of concentration in the inlet VOCs does not lead to the fluctuation of the concentration in the outlet of VOCs.The thermal recovery rate of the higher inlet VOCs is comparatively higher than the lower one.The change trend in thermal recovery rate is not obvious with the change of the concentration of inlet VOCs.The flow gas amount is an influencing factor of the thermal recovery rate.To increase the time of the gas staying time within certain minutes,which means to lower the amount of the gas flow,the VOCs destructive removal rate can not be improved significantly.However,the thermal recovery can be increased.Trough operation of more than one year,comparing with the previous methods,the new five chamber RTO technology has excellent advantages in the cost and efficiency to deal with the VOCs in the NBR production.After treated by RTO,the emission indexes improved from lower than 85%to 99%,the heat recovery improved from no recycling to more than 94%.The outlet concentration of AN decreased from 0-12mg/m³ to below 0.5mg/m³,the outlet concentration of BD decreased from0-6 mg/m³ to below 1mg/m³,the emissions does not only conform to the new environmental targets,but also reduce the emission of pollutants,which ensures the normal run of production.The RTO system has the features of stable operation and high efficiency,with the increasing environmental protection requirements of energy-saving and cost-reducing,the RTO technology would be widely used in waste gas treatment in the rubber industry.