三种生物质气一步法合成二甲醚的比较

COMPARISON OF SINGLE STEP DIMETHYL ETHER CATALYSTIC SYNTHESIS FROM THREE TYPES OF BIOMASS-DERIVED SYNGAS

比较了由生物质气化衍生的3种原料气:气体(A)(以空气-水蒸汽气化生物质得到)、气体(B)(在NiO-MgO固溶体催化剂上,添加沼气重整气体(A)得到)和气体(C)(在生物质气(A)中添加H_2调变气体组分得到)在双功能催化剂上一步法合成二甲醚的性能。3种生物质气的氢碳比(f=(P_(H_2)-P_(CO_2))/(P_(CO)+P_(CO_2)))值分别为0.33、0.88、0.66,P_(CO)/P_(CO_2).分别为0.49、6.08、1.89,其中气体(B)和气体(A)在相同氢分压下,两种气体的CO转化率(X_(CO))、DME选择性(S_(DME))、DME时空产率(STY_(DME))之比分别为1.52、1.43和2.95。3种气体在各自最佳合成温度下,X_(CO)分别为33.5%,47.6%和51.3%,STY_(DME)顺序为气体(A)<气体(B)<气体(C),气体(A)的时空产率为0.18g·(mL·h)^(-1),仅为气体(B)的1/3。当空速为1500～6000h^(-1)时,空速增加,3种气体的STY_(DME)均随之增加。在空速为1500h^(-1)时,气体(B)和气体(A)的STY_(DME)之比为1.65;当空速为6000h^(-1),两种气体STY_(DME)之比增大为2.43。

The single step dimethyl ether （DME） synthesis was carried out from three types of biomass-derived syngas （Gas A, Gas B and Gas C） over the bifunctional catalyst. Gas A was produced by gasification of biomass using air and steam as gasification mediums, Gas B was produced by reforming of Gas A on the NiO-MgO solid catalyst with suitable amount of appended methane and Gas C was produced by adding H2 to Gas A. The ratios of hydrogen and carbon （f = （ PH2 - Pco2 ）/（ Pco ＋ 1.5Pco2 ） ） of Gas A, Gas B and Gas C were 0.33,0.88,0.66, respectively and the ratios of Pco/Pco2 were 0.49,6.08,1.89,respectively, which affected the performance of synthesis greatly. The ratios of DME space-time yield （STYDME）, CO conversion （Xco） and selectivity ofDME （SDME） of Gas A and Gas B were 2.95, 1.52 and 1.43, respectively under the same hydrogen pressure. Under the optimal temperature, the corresponding Xco of three types of gas was 33.5%, 47.6% and 51.3%. The STYDME order was Gas A 〈 Gas B 〈 Gas C and the STYDME of Gas A was 0.18g（mL·h）^-1, which was only one-third of that of Gas B. The STYDME enhanced with the increment of GHSV between 1500- 6000h^-1. The ratios of STYDME of Gas B and Gas A were 1.65 and 2.43 when GHSV were 1500h^-1 and 6000h^-1, respectively.