Gaseous and Liquid Products

An appreciable fraction of thermally degraded coal may occur as such gases as hydrogen, carbon monoxide, methane, ethane, and ethylene. In fact, gas from a coal carbonization process has a calorific value of ca. 500 Btu/ft and, as such, is a medium-Btu gas upgrading of this gas by methanation is possible. 

Until about 1920, coal was the major source of ammonia but the onset of a blossoming petrochemical industry reduced the importance of coal as an ammonia source. However, recent shortages 

Ammonia can be recovered from coal gas by gas scrubbing to produce a dilute solution of ammonia that can be distilled to produce a concentrated ammonia liquor, but in many instances the ammonia gas can be stripped from scrubbing solutions by addition of base to raise the pH above the pH of ammonia, thereby enabling air stripping of ammonia gas from solutions  

The standard procedure for the manufacture of ammonium sulfate from coal gas involves several steps. The gas is first cooled to ca. 32°C (90°F) in an appropriate condensation system. Most of the tar, which is a very troublesome contaminant of ammonium sulfate (and vice versa), condenses and, in addition, much of the water containing approximately 25% of the ammonia, primarily as ammonium salts, also condenses. This water is rendered basic (lime treatment), thereby converting the ammonium ion to ammonia, which is recovered by being stripped off in a lime still and placed back in the coal gas stream. The coal gas stream is heated to above its dew point (approximately 65°C 150°F) and the ammonia is adsorbed in 5%-10% sulfuric acid solution contained in a lead-lined saturator at a temperature of 50°C-60°C (120°F-140°F) ammonium sulfate crystals precipitate from the sulfuric acid solution. 

In addition to ammonia, coal gas contains small quantities of miscellaneous compounds that may be removed for their own value or to improve the gas product among the more common of these are pyridine bases and hydrogen cyanide. The former are nitrogen-containing organic materials 

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The last defensive measure to control a runaway is to vent the gaseous and liquid products present in the system in a safe manner. The vent line may end in ... 

As expected, gaseous hydrocarbon yields and mineral carbonate decomposition increase with increases in temperature (Figure 9). The results are very encouraging—in all tests, over 90% of the organic carbon was recovered as gaseous and liquid products. At 1200°F, over 80% of the organic carbon was converted to liquids at 1400°F, over 60% was converted to gas. 

The quinolizine 1 (1.00 g, 2.75 mmol from pyridine and dimethyl acetylenedi-carboxylate) was heated to 220 °C for 10 h in an evacuated sealed tube or in a V2A-autoclave. Gaseous and liquid products were C02, CO, MeOH, MeOMe, CH3C02Me, OC(OMe)2 and (Me02C)2. The solid residue contained the indoli-zines 2, 3, 4 and 5 in the ratio 10 5 5 1. These were separated and isolated by preparative TLC on 400 g Si02 with benzene-methylacetate 3 2 (v/v). 

The authors would like to thank Mr. Gerald Farber for the construction and operation of the equipment, the U.S. Bureau of Mines for the coal analysis and Robert Smol, Joe Forrest, and Robert Doering of Brook-haven National Laboratory for the gaseous and liquid product analysis. Acknowledgement is also made to the group at City University of New York, Arthur Squires, Robert Graaff, and Sam Dobner for their helpful discussions on rapid reactions of coal with hydrogen. 

Yields of BTX and benzene peaked at about 1273°K whereas, the maximum ethylene yields were obtained at about 1100°K. The mass balances and yields of the gaseous and liquid products at one condition, 1273°K for 2 s, are given in Table 2. 

Low-temperature Fischer-Tropsch (LTFT) synthesis runs at temperatures between 200°C and 250°C [23-25]. The chain-growth probability at these conditions is much higher than for the HTFT, and as a consequence, the product distribution extends well into the liquid waxes. LTFT reactors are thus three-phase systems solid catalysts, gaseous reactants, and gaseous and liquid products. Both cobalt and iron... 

The coke produced is mostly elemental carbon and is used in applications described below. The gaseous and liquid products are valuable feedstocks for downstream processing or sometimes used as products. 

During pyrolysis, the yield of gaseous and liquid products can vary from 25 to 70 percent by weight, depending on a number of variables, such as coal type, type and composition of the atmosphere present, final pyrolysis temperature, time-temperature path, and pressure. Although certain operating conditions may lead to increased product yield, achieving these conditions may result in increased costs. 

In summary the operating temperature determines the amount of solid, liquid and gas products that are produced from a given pyrolysis process. At higher reaction temperatures more gaseous and liquid products are produced. However, at lower temperatures more coke-like solid is produced. Depending on the process and feedstock composition the optimal reaction temperature can be different. From an economic perspective higher amounts of gas and liqnid products are more beneficial. 

The difference in the composition of gaseous and liquid products of hydropyrolysis of plastic and biomass / plastic mixtures indicates the interaction between intermediate products of natural and synthetic polymers thenrnl conversion. The iron ore catalysts increase the yields of light liquid products and olefinic hydrocarbons. Producing of... 

C. Reaction Forming a Liquid Product-the Bawn Equation. A rate equation proposed by Bawn is applicable to reactions of solids forming gaseous and liquid products. In the latter case, the reaction rate is described by summing the reaction rates in the solid state and those in the solution formed by the liquid product ... 

In the recent studies of thermal and thermochemical processes of wood liquefaction, considerable progress has been reported in the analysis of gaseous and liquid products. Some attention has been given to the composition of the solid products by wet chemistry analysis... 

The use of non-toxic, non-flammable products which do not emit toxic and other poison gaseous and liquid products at elevated temperature at manufacture of materials and products from PVC ... 

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