02 Liquid fuels (transport, refining, quality, storage)

carbide. Both the iron oxide and carbide catalyst can selectively convert secondary alcohols to ketones and hydrogen. Fe:Os is reduced to FejOa during the conversion of secondary alcohols. Also both iron carbide and oxide catalysts dehydrogenate a primary alcohol. These results plus those of our earlier 14C-tracer studies suggest that dehydration of alcohols to produce olefins makes a minor contribution during Fischer-Tropsch synthesis with an iron catalyst at low and intermediate pressure conditions.

00/01718 Higher alcohol synthesis with Fischer-Tropsch elements Chen, X. Meitcw Zlturrdrrro. 1998. 21. (4). 22-28. (In Chinese) This paper reviews several types of higher alcohol synthesis catalysts. which contained Fischer-Tropsch elements. All of the Fischer-Tropsch catalysts could produce appreciable quantities of higher alcohols from carbon monoxide hydrogenation under suitable conditions. A homogeneous distribution of the Fisher-Tropsch synthesis sites and the sites that adsorb carbon monoxide associatively was necessary for the formation of higher alcohols, hence, it was thought that the physical distribution of surface active centres were more vital than other factors.

00/01719 Hydrocarbon selectivity model for the gas-solid Fischer-Tropsch synthesis on precipitated iron catalysts Laan, G. P. Ind. Wp. Chum. &r.. 1999. 38, (4), 1277--l 290. A continuous spinnmg basket reactor was used to study the kinetics of the gas-solid Fischer-Tropsch (FT) synthesis over a commercial Fe-Cu-K-SiO: catalyst. Experimental conditions were altered as follows: reactor prensurc of 0.8-3.2 MPa, Hz/CO feed ratio = 0.5-2.0 and a space velocity of 0.5-2.0 x IO-” Nm’ kg;,\ s-’ at a constant temperature of 523 K. This paper also proposes a novel product distribution model for linear hydrocarbons. Deviations from conventional Anderson-Schulz-Flory distribution can be quantifiably described with an rr-olefin readsorption product distribution model. From the experimental observations. it was apparent that the following can be predicted from this new model; a relatively high yield of methane, relatively low yield of ethene and both the exponential decrease of the olefin-to-paraffin ratio and the change of the chain growth parameter with chain length. It combines a mechanistic model of olefin readsorption with kinetics of chain growth and termination on the same catalytic sites. The hydrocarbon formation is based on the surface carhide mechanism by CHz insertion. The olefin readsorption rate depends on the chain length because of increasing physisorption strength on the catalyst surface and increasing solubility in FT wax with increasing chain length. In the kinetic model, the interfacial concentrations of reactive olefins near the gas-wax and wax-catalyst surface are used. With optimization of three parameters per experimental product distribution. the olefin readsorption product distribution model proved to predict product selectivities accurately over the entire range of experimental conditions.

00101720 Indirect coal liquefaction - where do we stand? Davis, B. H. Pwpr. - Am. Chcni. sm ., D;IK Per. Chcvn.. 1999. 44. (I ). 20-24. The recent developments in the commercialization of the Fischer-Tropsch synthesis are reviewed. The main emphasis of this paper is the reduction of costs in syngas manufacturing, such as the separation of gas using membranes and in the conversion of remote natural gas feedstocks into pipeline-transportable liquids and upgrading of petroleum residues to fuels and power. The recent announced corporate agreements between petroleum, natural gas, and energy companies; co-operative projects; and novel technology in reactor management and catalyst design are the main topics under discussion.

00/01721 Isotopic tracer study of the mechanism for Fischer- Tropsch synthesis Shi, B. and Davis, B. H. Prep. - Am Chow. Sock., Dir. Per. C‘/wm, I Y9Y. 44. (I), 106-l IO. This paper provides additional evidence to support the impact of hydrocarbon accumulation in a slurry-phase Fischer-Tropsch (F-T) reactor. In the study, ‘JC-labelled reactants, typically ethylene and ethanol were added to the process and the ‘“C was observed as it was incorporated into the chain growth in the F-T reaction. In addition, the role of initiation of chain growth was defined as it is related to the above added reactants. Both alkenes and alkanes in the lower carbon-number fractions exhibited the same constant radioactivityimol. as would be required if both compared classes were formed by a common reaction mechanism. The higher carbon- number alkenes also exhibited a constant radioactivityimol. whereas the alkanes did not, which was consistent with these products being diluted with alkanes produced prior to the period when the tracer is added. The products formed by the isotopically labelled compound, that act as chain initiators were diluted by the accumulated alkanes.

00101722 Kinetics of Fischer-Tropsch synthesis over Fe-Cu-K catalyst. (I). Kinetic model on the basis of mechanism Ma, W. H~rcrxong XI&/~ lChOl. Ed.). 1999. 50. (2). I59%166. (in Chinese) On the basis of the carbide mechanism a kinetics model of Fischer-Tropsch was derived in which the readsorption of olefins was considered. The chain growth factor in the derived models was no longer a constant, hence the new model is ideal for interpreting non-ideal Anderson-Schulz-Flory distribution on an iron-based catalyst.

00/01723 Kinetics of Fischer-Tropsch synthesis over Fe-Cu-K catalyst. (II). Model discrimination and parameter estimation Ma. W. N~rc~,er~rr,e ~r&m iClri/r. Ed 1. 1999. 50. (2). 167~ 173. (In Chinese) For the kinetics models ot Fischer-Tropsch synthesis (FTS) and water gas shift reaction (WGS) obtained in the previou% paper. the model discrimination and parameter estimation were performed on the hasis of kinetrc data measured hy using a fixed hed reactor. The results demonstrate that the best models for fitting the experimental data are the model of FTI which takes into account the effect of olefin readsorption on product distribution and the model of WGI. which is derived by assumption of CO? desorption step as the rate determining \tcp. The requirement of statistic test (F-test) are met hy the final models for FTS and WGS at a YSQ confidence level. The value of kinetic parameters for the final models agreed well with the data reported in literature.

00/01724 Meeting requirements for automobile fuels in relation to the development of internal combustion engines Kossowicz, L. ,Vrt//o-(;(~:. IYYY. 55. (I I. i2 41. (In Polish) Improvements in the refining of crude oils results in a better quality of liquid fuels that consume more energy with increased carbon dioxide emission. The hydrocracking and cracking rn the refineries renders the marketed fuels to synthetic furls.

00101725 Mossbauer study of precipitated unpromoted iron Fischer-Tropsch catalyst Zhang, Y. Prr~pr. Am. Clrrm SW. D~I, PC,/ C/ww.. 1999. 44, (I ). 100-102. The Mosshauer study results on the content and type of iron phases in CO- activated and ayngas-active precipitated unpromoted iron-based Fischer- Tropsch catalysts in a slurry-phase C‘STR at high conversion levels. Following carbon monoxide activation but hefore the active Fischer- Tropsch reaction. the distribution of iron phases wa\ 04% k-FeiCZ-FclO,: during active Fischer-Tropsch reaction, the \-FciC2 was oxidized to Fe>O,. until no dctectahle carbide phase was ohserved after 4.53 hours onstream. Observation\ were made of a strong correlation hctwcen iron carbide content and Fischer-Tropsch actrvity.

00101726 Natural gas to hydrocarbon liquids Wilson, G. R. and Carr, N. L. Inr. .J. N~,r/ror,<,rhr>n E/r,e.. IYYX. 3. (4). 43. 45 47. Palladron Publications Ltd. Using the syncrude technological process the Fischer-Tropsch synthesis of high-quality diesel fuel and naphtha from natural gas was described, The procedure involves: the separation of air and autothermal reforming of natural gas to prepare 2.0: I (Hz-CO) synthesis gas. (2) a two-stage F-T reaction rn a slurry huhhle column reactor using promoted cobalt catalysts, and (3) mild wax hydrocraking to recover LPG. naphtha. and middle distillate. l-he system has also heen set up for additional purposes including the co-production trf electric power for plant requirements or for export to outside network\.

00101727 Novel activation of ColSiO, catalysts prepared by alkoxide method for Fischer-Tropsch synthesis Okahe. K. Pr~pr. .4111. Chem. So< ., Dil,. PC/. Clmi.. I YYY. 44. (I ). 9% 96. Small amounts of noble metals such as rhenium and iridium can be used in the promotion process of silica-supported cobalt catalysts. After the Fischer-Tropsch catalysts have undergone reduction and activation (in HZ at 773 K) they can be used in the production of transportable liquids from remote natural gas fields. The catalysts were prepared hy the alkoxide method. in which Co(NOx): is dissolved in ethylene glycnl. mixed with tetra-Et orthosilicatr and hydrtrlysed to form a glassy gel that was dried and calcincd prior to imprcgnatron with the noble metal. The cxpcrimcntal results indicate that the nohlc mcta-promoted catalysts had turnover frequencies (TOF) that wcrc two-three time\ greater than the TOF of conventional catalysts prepared hy impregnation.

00/01728 Processes leading to increase of alkyl chain lengths under hydrous pyrolysis conditions Barth, T. and Hansen. B. G. Prep! .T~orp .4/rr. C/11.111. sot DilV F-d C‘lmr.. 199’). 44. (2). 397 400. The alkyt chain generation in ‘classical’ hydrous pyrolysis of simple compounds will he presented. Information will also he included on the reproduction of a series of organic acids found in waters in the vicinity of oil and also contribute to the long-chain hydrocarbon compounds that are found in the petroleum phases. A discussion will also he included on the applicability of the Frscher-Trrrpsch mechanism for the polymerization step.

00101729 Product control in Fischer-Tropsch synthesis Tsubaki. N. and Fujimoto, K. I;trc,l. Prw. 7’c~~lmol.. 2000. 63. (2-3). I73 I X6 High quality liquid furls for diesel engine arc normal paraffins with C,,,- C2,,. ‘The most promising method to make them from other carbon resources is the Fischer-Tropsch synthesis (F-T) which gives wide range of product distribution. Higher paraffins can he cracked with a conventronal method to diesel fraction while lighter ones cannot. The authors have developed a new F-T process that makes wax products selectively with reduced gaseous products. Efficient transportation of reactants and products to the inside of catalyst hed and pellet. quick heat-transfer and in situ wax extraction from catalyst hy supcrcriticat fluid were accomplished. The procrr\ is operated under supcrcritical conditions of light paraffins and

198 Fuel and Energy Abstracts July 2000