摘要:

In light of environmental concerns and the global economy, higher oxygenated fuel, such as ethanol, is a viable and attractive alternative to conventional gasoline. Presently, the major process to produce ethanol, the fermentation of corn, is economically inefficient. A more direct route, the reaction of synthesis gas (CO/H2) to produce higher oxygenates (aldehydes and alcohols), appears to be a better method. Rhodium catalysts have been known to exhibit higher oxygenate activity and selectivity from synthesis gas. The mechanism involves CO dissociation followed by hydrogenation to form an adsorbed CHXspecies. The CHXintermediate can undergo either hydrogenation to form methane, chain propagation to form higher hydrocarbons, or CO insertion to form C2oxygenates. Experiments were performed to study the effects on the synthesis of higher alcohols from syngas of S, P, Cu, and Ag as additives to Rhodium supported on a silica support (Rh/Si02). The additive S was found to suppress the CO dissociation step, therefore lowering the overall product rate. The addition of P or Cu to the Rh catalyst enhance the CHXintermediate hydrogenation, resulting in the increase of methane formation. The addition of Ag to Rh/SiO2promotes the CO insertion activity, therefore increasing the oxvtfenate selectivity.

ISSN:0884-3759    

DOI:10.1080/08843759108942296

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The oxidative deterioration of petroleum products (change in physical/chemical properties upon prolonged storage under “ambient” conditions) is a complex, yet fascinating problem. For gasoline and jet fuel, a peroxyl radical chain oxidation mechanism is most likely operative during oxidative deterioration. For oxidatively reactive diesel fuel and asphalt, the available experimental evidence suggests that oxidative degradation is not a classical peroxyl radical chain. It is proposed that ETIO is consistent with the available experimental data for oxidatively reactive diesel fuels and asphalt. This paper will critically review pertinent literature dealing with the oxidative degradation of fuel products with focus upon evidence that illustrates the distinction between ETIO and peroxyl radical chain mechanism of oxidative deterioration.

ISSN:0884-3759    

DOI:10.1080/08843759108942297

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Samples from two major deposits of Turkish lignites were subjected to supercritical toluene extraction at 325°C and 14.1 MPa in an autoclave. The resultant extracts were separated into pre-asphaltene, asphaltene, saturates, aromatics and resin fractions by column chromatography. The fractions were characterized by1H-NMR,13C-NMR, IR. and elemental analysis in order to compare the chemical composition of extracis from the two coal samples. The results show that the extracts from the Tungbiiek (T-coal) deposits contain aliphatic constituent which is composed of mostly long chain unbranched alkyl compounds while the extracts from the Soma Mcrkeg (S-coal) deposits contain a significant amount of branched paraffinic compounds. The resin fractions from both samples were found to contain a significant amount of single ring aromatic compounds.

ISSN:0884-3759    

DOI:10.1080/08843759108942298

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A kinetics model of the upgrading of shale oil in supercritical water (SCW) was developed. The model predicts the yields of coke (C)asphalt (A), resid (R), distillate (D) and gas (G), as well as nitrogen (N) removal as a function of batch reaction or plug flow holding time, from the reaction of shale oil in SCW with added catalyst and hydrogen. Mechanistically derived submodels provide the functional dependence of the overall rates of reaction of C, A, R, D and G on process variables. The model can be utilized in two complementary ways. First, it is a quantitative summary of mechanistic insights and hypotheses that suggest further laboratory testing. Second, it can be useful in process engineering calculations.

ISSN:0884-3759    

DOI:10.1080/08843759108942299

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Metals are present in petroleum depending on age and conditions of diagenesis, and concentrate during refining in heavy fractions and residua. Nickel and vanadium show particularly deleterious effects on catalysts, such as poisoning, excessive gas and coke formation. Besides, removing vanadium from fuel oils reduces the environmental impact of “acid rain” due to the oxidation of sulphur dioxide in the atmosphere.

ISSN:0884-3759    

DOI:10.1080/08843759108942300

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The perchloroethylene coal cleaning process has proven to be very effective in removing both organic and pyritic sulfur from high-sulfur coals. The process removes 30%- 70% of the organic sulfur and 90%- 99% of the pyritic sulfur with very little loss (<1.0 wt%) of hydrocarbons and their heating value. The process has been investigated on a bench- scale and a fully continuous, mini-pilot scale (5 kg/hr). This paper discusses scientific and technological issues related to the process engineering and the reaction chemistry of the process. The objective of this paper is to report the status of the process development and to address the important issues of the process commercializability.

ISSN:0884-3759    

DOI:10.1080/08843759108942301

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In part I of this series on the development of a single-stage, liquid-phase dimethyl ether (DME) synthesis process from syngas, the process feasibility and the process variable effects on the dual catalyst activity were discussed. This part focuses on the comparison of the single-stage reactor productivity of liquid phase methanol synthesis to that of the co-production of methanol and DME. It is experimentally demonstrated that the single-stage reactor productivity for the co-production of methanol and DME could be as much as 60% higher than that for liquid phase methanol synthesis alone. Along with this, a 50% increase in the syngas conversion is also obtained. Further, this approach is shown to co-produce methanol and DME in any fixed proportion, ranging from 5% DME to 95% DME, at significant synthesis rates of DME.

ISSN:0884-3759    

DOI:10.1080/08843759108942302

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor