Performance And Mechanism Research On CO₂Adsorbent Of DBU Loaded On GAC

Greenhouse effect caused by the greenhouse gases in the atmosphere is currently one of the most major environmental problems facing to humans. In a variety of greenhouse gas, carbon dioxide (CO2) is the most important anthropogenic greenhouse gas, coal-fired power plants is the centralized source of CO2, its CO2emissions account for about30%induced by CO2total human activity emissions, so the study of stable and efficient coal-fired power plant flue gas CO2trapping technology become an important development needs during the" Twelfth Five-Year Plan" period. It was verified that DBU performed an excellent absorption properties on CO2through the DBU solution absorption experiment in this article. And supported1,8-diazabicyclo [5,4,0] undec-7-ene(DBU) on granular activated carbon(GAC) to prepare different load rate of DBU-GAC adsorbent, the absorbent pore were characterized by nitrogen adsorption, absorbent thermal stability characterized by thermogravimetric experiments, carried out atmospheric fixed bed adsorption experiment to study the adsorption behavior of CO2by DBU-GAC type absorbent, through the analysis of the adsorption breakthrough curve, the adsorption isotherms, adsorption capacity, adsorption capacity prediction as well as the condition of various factors on the adsorption behavior of, to explore the laws of adsorbing CO2by DBU-GAC adsorbent.Data in the solution absorption experiment indicates that the DBU solution unit molar absorption is higher than the amount of ETH, DEA and TEA three kinds of amine solution, only per unit mass absorption volume of DEA solution is close to the same volume concentrations of the DBU unit mass absorption; DBU solution is faster and more sufficient in absorbing CO2; DBU solution showed good trapping efficiency to CO2at room temperature, it will be significant to carry out a series of experiments to study the effect of DBU CO2capture.The data analysis on the preparation of adsorbents showed that DBU can effectively loaded in GAC pore and on surface. The lower DBU is added, the higher effective load rate and utilization rate of DBU is. Nitrogen adsorption analysis experimental research shows that as the DBU load increases, the load rate is gradually increased, the GAC average aperture showed a gradual increase trend; DBU to GAC pore structure sealing effect exists mainly in the GAC micro and small aperture; the load of DBU did not effect much to the shape of mesoporous. Thermal analysis experiment research showed a small amount of precipitation of DBU adsorbent at a temperature of140℃, and as the load ratio increases, the precipitation amount increases gradually, quality stable became longer; when the temperature rises to200℃, DBU precipitation amount as well as the precipitation rate increased. DBU-GAC adsorbent has better thermal stability at less than140℃; polar DBU can easily combined with water, can inhibit the adsorbent water evaporation, this is helpful for water consumption reaction of DBU and CO2.It was obtained through the analysis of DBU-GAC type adsorbent of atmospheric fixed bed adsorption experiment data that CO2adsorption in granular activated carbon is mainly micropore filling and showed large volume of adsorption amount during initial adsorption period, while adsorption reaches a saturation state rapidly after breaking-through; during the capturing process of CO2by adsorbent in simulated flue gas, although the load of DBU on GAC increased the chemical adsorption capacity of adsorbent to CO2, the film sealing effect generating by the load of DBU will influence the physical adsorption and chemical adsorption capacity to CO? of DBU-GAC adsorbent; DBU load ratio nearby between A-land A-2(5%-11%) performed better adsorption capacity of the adsorbent also performed the best adsorption effect. Through the analysis of adsorption isotherm curve:under298K,303K and308K three different temperature conditions, the KF value of the four adsorbent sample order is:A-1>A-0> A-5> A-10,A-1showed the strongest adsorption affinity and maximum adsorption quantity to CO2. By analysis and forecast that to the adsorption capacity was significantly lower using high load rate of the adsorbent samples than that of low load rate of sorbents; membrane sealing effect became stable when the adsorbent load reaches a certain value, the adsorption amount of inhibitory effect has become saturated; after multiple cycles, GAC pore condition gradually improved, passing through of the simulated flue gas stream helped unclog pores, meanwhile, high load rate of adsorption capacity will rise slightly, low load rate of adsorption amount will appear slightly downward trend. According to the conditions under the different factors of the adsorption behavior that about15%of the amount of water vapor is the optimal adsorption condition;150mL/min gas flow rate of the best conditions of adsorption; adsorption agent through the cycle of repeated use performance remains stable.