Liquid products from hydrogenation

A flow diagram for the commercial process is shown in Figure 3. Molten carboxylic acid is fed into the vaporizer where the acid is quickly mixed with hydrogen gas and evaporated. The reaction is slightly endothermic and the mixture is pre-heated and introduced on to the catalyst bed. The reaction is performed at 350-400°C under a hydrogen pressure of 0.1-0.5 MPa. The effluents are condensed to separate the liquid products from hydrogen and the excess hydrogen is recycled to the reactor. Aldehydes are further purified by distillation. 

Major work on zinc chloride catalysts for hydrogenation and hydrocracking of coal has been carried out by Zielke, Gorin, Struck and coworers at Consolidation Coal (now Conoco Coal Development Co.) (1). The emphasis there has been on a full boiling-point range of liquid product, from treatment at temperatures between 385 and 425°C and hydrogen pressures of 140 to 200 bars. 

The principle of donor hydrogen reaction with coal has been applied in various ways in processes for coal liquefaction. In one application, hydrogen donor solvent is generated from the coal itself. The solvent, usually a distillate fraction of the coal liquid product, is hydrogenated and recycled to the coal liquefaction reaction. 

The product coming out of the reactor consists of excess hydrogen and a reformate rich in aromatics. Typically the dehydrogenation of naphthenes approaches 100%. From 0% to 70% of the paraffins are dehydrocyclized. The liquid product from the separator goes to a stabilizer where light hydrocarbons are removed and sent to a debutanizer. The debutanized platformate is then sent to a splitter where Cg and C9 aromatics are removed. The platformate splitter overhead, consisting of benzene, toluene, and nonaromatics, is then solvent extracted (46). 

Properties of the charge stocks and liquid products from the various hydrogenation runs are shown in Table IX. Hydrogenation of the 550°-850°F heavy oil under the conditions used reduced the nitrogen content from 16,100 ppm in the charge stock to 935 ppm in the 550°-850°F... 

By operating without catalysts but using caustic and alcohol for generating hydrogen in the autoclave, Lautsch and Piazolo (15) were able to obtain liquid products from lignin and lignin sulfonic acid. The products were obtained as extremely complex mixtures with little commercial value. 

Figure 13. Change in composition of the liquid product from hydropy-rolysis of 2 as a function of hydrogen pressure temperature 575° C ...

Nonaqueous ionic liquids have been used for hydrogenation of arenes and other liquids [67, 68]. By selecting a stable catalyst that is soluble in the ionic phase, purification of products began by separating the liquid products from the ionic liquid containing the catalyst. Because of the expense of nonaqueous ionic liquids, the ability to recover and reuse these materials will be important to control costs if they are to be used on scale. 

For exothermic reactions, AH is negative because the energy stored in the products is less than that in the reactants. For endothermic reactions, AH is positive because the energy of the products is greater than that of the reactants. The value of AH is often shown at the end of a chemical equation. For example, the exothermic formation of 2 mol of liquid water from hydrogen and oxygen gas would be written like this. 

Some insight into the utility of shale oil can be gained by comparing its composition with coal-derived liquids and petroleum crude oil. See Table III. Two representative liquid products from coal are shown COED product, produced by carbonization or coking, which, like retorting of shale, is a thermal step (4), and a liquid from the H-Coal process by coal hydrogenation (5). Arabian Light crude oil is also shown. 

None of the above authors report coke (carbon) formation nor do they mention any hydrogenated C6 liquid products. However, hydrogen balances on the data of Schultz and Linden (4) reveal that the empirical formula C6HW of the C6+ components does change from n = 6 to n = 8... 

The effect of various hydrogen pressures upon the inhibition of the disproportionation of pentanes was investigated (Evering et al., 31). The reaction was carried out in a 1490 ml. capacity reactor which was stirred mechanically. The reactor was jacketed so that it could be quickly heated by steam or cooled by water. Provisions were made for the withdrawal of the liquid product from the settled aluminum chloride catalyst. The experimental results obtained are summarized in Table XXI. 

The liquid products from both the carbonization and hydrogenation stages of the process are combined for further processing to yield synthetic liquid fuels and a variety of other coal products. The gases are treated for sulfur and ammonia removal and are also capable of acting as a source of valuable materials other than the usual fuel gas. 

Liquefaction The conversion of coal into nearly mineral-free hydrocarbon liquids or low-melting solids by a process of direct or indirect hydrogenation at elevated temperatures and pressures and separation of liquid products from residue by either filtration or distillation or both. 

The TBP-GLC s on the liquids are for calculation of yields of various boiling range liquid products. The C/H/S analyses are used for elemental material balance, calculation of heats of reactions and calculation of hydrogen distribution, i.e., hydrogen content of liquid product. From the material balance and the product analyses, a final yield report is made as shown in Table II. With each yield report, the operating conditions are reported which include tube identification, hydrocarbon and water feed rates and pressure and bulk gas temperature profiles. 

Liquid synthetic fuels include shale oil and its various fractions coal liquids by cooking, by hydrogenation, and by Fischer-tropsch synthesis methyl fuel from coal or from overseas natural gas and liquid products from biomass, probably by gasification and Fischer-Tropsch synthesis. 

Figure 16-17. Simplified flow diagram of Cryofining process for recovering high purity hydrogen and liquid products from refinery fuel gas /Ur Products and Chemicals, Inc. 19961. Reproduced with permission from Hydrocarhon Processing, Jtpril 1996...

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