Research And Application Of Low Temperature Integral CO-SCR Denitrification Catalyst System

Controlling nitrogen oxide emissions is essential because it has a certain impact on human health and the environment.At present,there are many technologies for NOx reduction,among which selective catalytic reduction（SCR）is one of the most effective technologies for flue gas NOx removal.In the past few decades,a large number of researchers have used reducing gases such as ammonia,hydrogen and carbon monoxide to remove NOx,in which CO as a reducing agent reduces the emission of nitrogen oxides from mobile or fixed sources,providing a simple and low-cost technology because both NO and CO polluting gases can be removed at the same time.CO-SCR has been developed for so many years.Most CO-SCR catalysts are still staying on powder catalysts.There is less research on monolithic CO-SCR catalysts and less research on monolithic denitrification catalyst system.In this thesis,the performance of catalysts is evaluated by building a pilot and pilot plant of monolithic catalysts.The low-temperature monolithic CO-SCR denitrification catalyst system is comprehensively studied as follows:（1）.Small-scale system and application of low-temperature monolithic CO-SCR denitrification catalyst.Firstly,a set of low temperature monolithic CO-SCR denitrification catalyst pilot plant was built and CuCe composite metal oxide monolithic catalyst was prepared.The prepared catalyst was applied in the pilot plant to explore CO reduction reaction to NO.Under the conditions of air speed 1667 h^-1,oxygen content3%,temperature 120℃,the highest conversion rate of NO reaches 76%,and the final stability is about 65%.Combining with Raman,XPS and H2-TPR analysis,it is found that the catalyst for preparing the precursor has a high concentration of oxygen vacancy,and the interaction between copper and cerium is high,which continuously produces low-valent reduction species,which has an important influence on the catalytic activity of the catalyst.（2）.Pilot-scale system and application of low-temperature monolithic CO-SCR denitrification catalyst.Based on the research on small scale system and application of low-temperature CO-SCR monolithic denitrification catalyst,the scale of testing device is extended,and the performance of monolithic catalyst is evaluated under actual flue gas conditions to be closer to the actual situation.A set of pilot-scale engineering drawings for CO-SCR denitrification catalyst is planned and designed,and a set of pilot-scale plant for low temperature CO-SCR denitrification catalyst is built.At the same time,a set of flue gas boiler equipment is matched with the self-made flue gas.Repeatedly debugging equipment parameters,gas-air ratio,flow rate,position of measuring port,etc.,to make the equipment operate stably and continuously,and the flue gas concentration can be adjusted,which is convenient for the subsequent test of monolithic denitrification catalyst.At the same time,based on the experience of preparing catalysts after the preparation of precursors and preparing catalysts by impregnation,the carrier of catalysts was improved,and a highly efficient two-dimensional（2D）vermiculite（VMT）supported copper-cerium catalyst（CuCe/2D-VMT）was synthesized and used for CO-SCR reaction.It was found that the catalysts had oxygen content of 9.2%,temperature of120℃and NO conversion rate of about 55%even under real flue gas conditions.CuCe/2D-VMT catalyst shows excellent catalytic activity.XRD and Laman characterization analysis prove that copper-cerium doping is more uniform and vermiculite provides more oxygen vacancies.The anti-oxygen mechanism of CuCe/2D-VMT catalyst is given.The pilot system application of low temperature monolithic CO-SCR denitrification catalyst was realized.