Synthesis of Liquid Fuels and Chemicals via Continuous Catalystic Process
Date Issued
2010
Date
2010
Author(s)
Chang, Hua-Yu
Abstract
This study examined the feasibility and operation performance of reforming of synthesis gas (syngas, CO and H2) via high pressure catalytic packed bed (HPCPB) process. The effects of variation of temperature (T), change of H2/CO ratio, addition of MoS2/γ-Al2O3 and Pt/γ-Al2O3 catalysts and presence of H2O vapor on the conversion of CO (XCO) and the production rates (R), selectivities (S) and yields (Y) of alcohols and other hydrocarbons (HCs) were elucidated. The experimental conditions, in general, were as follow: (1) total pressure of inlet gas, PST = 3.10 MPa or 450 psi (reading at 298 K), (2) temperature, T = 523 K, (3) gas flow rate, QG = 300 mL min-1, (4) H2/CO = 2 (vol./vol.), (5) mass flow rate of CO, mCO = 6.857 g h-1and (6) mass of catalyst, mS = 25 g. The results indicate that XCO and production rates R of C1-C3 alkanes for the case using MoS2/γ-Al2O3 increase with increasing T from 423, 473, 523 to 573 K. At T = 573 K, XCO = 8.19%, R of CH4 (RCH4) = 194.1 mg h-1 and selectivity S of CH4 (SCH4) = 34.57%. As for the production of C2H5OH (EOH), the maximum REOH (= 134.25 mg h-1) takes place at T = 523 K with corresponding XCO = 8.10% and SEOH = 51.98%. At further high T = 573 K, the EOH is decomposed to other simple HCs, for examples C1-C3 alkanes. Thus, for the production of more alcohols with less alkanes, the temperature at 523 K is the optimal choice. At T = 523 K with H2/CO reduced to 1, the values of XCO, REOH and SEOH decrease to 7.55%, 110.46 mg h-1 and 44.81%, respectively. As Pt/γ-Al2O3 was used replacing MoS2/γ-Al2O3, at H2/CO = 2 the XCO decreases to 6.79%. The major product is MOH with RMOH and SMOH as high as 395.63 mg h-1 and 84.93%, respectively. However, due to the cause that Pt was poisoned by CO, Pt/γ-Al2O3 was deactivated after 5 h reaction, being not suitable for the long-time reaction requirememt. As for comparation, the use of γ-Al2O3 gives very low values of RC1, RC2, RC3, RMOH and REOH of 0.34, 0.04, 0.029 and 0.368 mg h-1 ,respsctively. No production of C3H8, C4H10, CH3COH, C3H7OH and C4H9OH were detected. It comes to the results that MoS2/γ-Al2O3 and Pt/γ-Al2O3 contribute to the formation of alcohols. However, the use of MoS2/γ-Al2O3 also yields C1-C3 and C3HCHO. Moreovre, the introduction of H2O vapor results in the increase of yield of alcohol of about 0.63% (=5.59% - 4.96%), and the reduction of that of non-alcohol products of 1.0% (= 3.14% - 2.14%), respectively. As for the selectivity, the presence of H2O vapor enhances the S of alcohol of 4.8% (= 70.7% - 65.83%) while decreases that of alkanes of 5.78% (= 26.96% - 20.91%).
Subjects
Catalytic synthesis
liquefaction
MoS2/γ-Al2O3
Pt/γ-Al2O3
alcohol
Type
thesis
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