The Study Of Cu Catalysts For Higher Alcohols Synthesis From Syngas

In recent years, the application value of higher alcohol in fuel and chemical industries gradually emerged. It is of economic significance and environmental potential to use higher alcohol made from syngas as an alternative fuels and chemical industrial raw materials. employing coal gasification alcohol synthesis experimental apparatus, this dissertation investigated the synthesis of higher alcohols from CO hydrogenation. Through experimental analyses of H2 and CO conversion, the selectivity of CH4, CO2 and total alcohol, as well as the distribution of alcohols, obtained optimum conditions(reaction temperature, pressure, airspeed and H2/CO). The dissertation also uses analytic methods such as XRD, BET to rep resent different catalysts and explore their catalytic mechanisms.The dissertation studies the effects of preparation methods and vectors on Cu-Co/MO catalytic performance, optimizes and explores the optimum process conditions. Zr O2, Zn O, Mg O, Al2O3 are selected as carriers to prepare Cu-Co / MOx catalyst. By comparing the structure parameter and catalytic activity of Cu-Co catalyst prepared by both the co-precipitation method and impregnation method, optimum catalyst is selected and the effects of process conditions on the catalytic properties are explored. The results show that Cu-Co/Zn O catalyst prepared by impregnation has a higher CO conversion rate and alcohol selectivity, and that the most suitable reaction conditions are 623 K, 8MPa, H2/CO = 2: 1. In this condition, CO conversion rate is55.1%, C2 + alcohol selectivity is 59.45 g /(kg·h) and isobutanol selectivity is 22.9%.The dissertation also studies the effects of calcination temperature, catalyst loading Ce on the catalytic properties of Cu-Ce /Mg O, optimizes and explores the optimum process conditions. CO conversion increases with the increase of calcination temperature in the first stage, then decreases as the temperature continues to rise in the second stage, and 450 ℃ is the best firing temperature. Ce and Cu can produce a strong interaction. An appropriate amount of Ce is not only effective in inhibiting the growth of Cu O crystal grains, but also makes Cu O easier to be redoxed, thus improving the dispersion of the active ingredient Cu. The catalytic properties of 10% Ce-Cu-Mg catalyst perform best at 673 K, 8MPa, H2/CO = 2: 1, under which the COconversion is 68.09%, and the space time yield of total alcohol reaches 127.40 g/(kg·h).Besides, The dissertation explores and optimizes the impact of process conditions on the higher alcohol synthesis from syngas prepared by the use of Cu-Mn-Zr O2/Al2O3 catalytic. Pressure increase renders the increase of conversion rate of CO, at the same time increasing the selectivity of alcohol; with space velocity increasing, contact time of the catalyst and the reaction gas decreases, then CO conversion rate decreases; when reaction temperature increases, CO conversion rate increases, and alcohol space-time productivity firstly increases, then decreases; With the H2/CO ratio increasing, CO conversion rate increases, and the space-time productivity of alcohol continuously decreases; With the increasing H2/CO ratio rising,methanol selectivity increases, while C2+OH selectivity in the total alcohol product shows a decreasing trend. Therefore, optimal conditions for Cu-Mn-Zr/Al2O3 catalyst Alcohols are as follows: airspeed is 6000h-1, the reaction pressure is 8MPa, the reaction temperature is 673 K and H2/CO = 1.5:1. In this condition, CO conversion rate is 53.2%, and the space-time productivity rate of total alcohol is 194.7g/(kg · h).