Solvent hydrogen content

This becomes more aromatic and carbon-rich as it generates petroleum and evolves toward graphite. In contrast, the solvent-extractable lower molecular weight organic materials called bitumen or extractables increase in hydrogen content and progress through compositions typical of cmde oils to those of gas (10). 

In this work, various Ru-BINAP catalysts immobilized on the phosphotungstic acid(PTA) modified alumina were prepared and the effects of the reaction variables (temperature, H2 pressure, solvent and content of triethylamine) on the catalytic performance of the prepared catalysts were investigated in the asymmetric hydrogenation of dimethyl itaconate (DMIT). 

Copper, silver, and gold colloids have been prepared by Chemical Liquid Deposition (CLD) with dimethoxymethane, 2-methoxyethyl ether, and ethylene glycol dimethyl ether. The metals are evaporated to yield atoms which are solvated at low temperatures and during the warm-up process colloidal sols with metal clusters are obtained. Evaporation of the solvent was carried out under vacuum-generating metal films. These films are showing very low carbon/hydrogen content and were characterized by elemental analyses and infrared spectroscopy (Cardenas et al., 1994). 

Midwest utilities are coal burners. They have the know-how and facilities to utilize solid fuels. Solvent refined coal, which has the potential of being the lowest cost coal liquefaction product because of its low hydrogen content, is of interest to this group. 

A comparison of the effect of the two solvents on the composition of SRCs from Wyodak subbituminous coal is shown in Figure 8. Compared to the hydrogen-enriched solvent, use of the hydrogen-depleted solvent results in a SRC with higher sulfur and oxygen contents and lower carbon and hydrogen contents. 

There are indications that the formation of these initial hydrogen enriched products and the rate at which the hydrogen content subsequently decreases is dependent upon the solvent donor capacity. 

It should be noted that these models only consider the cyclic carbon structure no heteroatoms or side chains have been included. Though this may not be totally accurate one very important observation is that the extent of ring condensation increases dramatically. This implies that the portion of coal which becomes hexane insoluble (SRC) products is extensively dehydrogenated even when high hydrogen content process derived solvent (92-26-019) is used. 

Alkylation of solvent represents still another pathway for changing the properties of a recycle solvent. If we consider alkylation in terms of the transfer to methyl groups from coal to solvent components, then there are several structural and physical changes that occur to the solvent. Alkylation will increase the hydrogen content of the solvent at the expense of coal since the solvent molecule will have a C-H replaced by C-CH. This represents an increase in the aliphatic content and conversely a decrease in the aromatic content of the solvent. Kleinpeter (7) has indicated that alkylation of condensed aromatics is a problem. High aliphatic character will decrease the ability of the solvent to act as a physical solvent for coal liquefaction products. 

Figure 3. Hydrogen absorption rates effect of hydrogen content of solvent. The asterisk indicates where the reaction was stopped and the reactor was vented and repressured with fresh hydrogen.

Primary coal liquefaction products from three processes— solvent-refined coal, Synthoil, and H-Coal—were hydrotreated. Upgrading was measured in terms of the decrease in heptane and benzene insolubles, the decrease in sulfur, nitrogen, and oxygen, and the increase in hydrogen content. Hydrotreating substantially eliminated benzene insolubles and sulfur. An 85% conversion of heptane insolubles and an 80% conversion of nitrogen was obtained. Catalyst stability was affected by metals and particulates in the feedstocks. 

This chapter reports results of applying a catalytic hydrorefining process to four coal liquids solvent-refined coal (SRC) process filter feed, SRC extract product, Synthoil, and H-Coal process hydroclone underflow. The achieved upgrading is evaluated in terms of reduction in benzene and heptane insolubles, reduction in sulfur, nitrogen, and oxygen, an increase in hydrogen content, and a yield of lower boiling products. 

Creosote oil was chosen as substitute solvent because of its coal source and its similarity in ring composition to SRC distillate. The hydrogen contents of these oils are lower than for conventional recycle solvents. Koppers Tar has a 6.1% hydrogen content whereas the SRC distillate from Tacoma used in this study has an 8.2% hydrogen content. 

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