Destructive distillation of coal

Coal gas for illumination—and later for heating— was produced by the destructive distillation of coal and resulted in the production of large volumes of tar. This is used in the form of creosote for wood preservation, so that both gasworks sites and impregnation facilities became heavily contaminated with coal tar products. The range of compounds involved is enormous, but attention... 

The production of coke involves the heating of coal in the absence of air, called the carbonization or destructive distillation of coal. Carbonization, besides its main purpose of production of coke, also results in a coproduct called coke oven gas from which various liquid products such as tar, benzol, naphthalene, phenol, and anthracene are separated. There are two main types of carbonization based on the temperature to which the coal is heated in the absence of air. One type is low-temperature carbonization (LTC) the other is high-temperature carbonisation (HTC). Some features of LTC and HTC are listed in Table 1.28. The LTC Process is mainly carried out to manufacture domestic smokeless fuel. This presentation, however, concentrates on the HTC process by which metallurgical coke is produced. 

An important raw material used in the manufacture of steel is coke, a nearly pure form of carbon. To supply themselves with coke, steelmakers developed the process of destructive distillation of coal. 

The early sources of phenol were the destructive distillation of coal and the manufacture of methyl alcohol from wood. In both cases, phenol was a by-product. Recovered volumes were limited by whatever was made accidentally in the process. Initial commercial routes to on-purpose phenol involved the reaction of benzene with sulfuric acid (1920), chlorine (1928), or hydrochloric acid (1939) all these were followed by a subsequent hydrolysis step (reaction with water to get the -OH group) to get phenol. These processes required high temperatures and pressures to make the reactions go. They re multistep processes requiring special metallurgy to handle the corrosive mixtures involved. None of these processes is in commercial use today. 

Benzofuran is a colorless organic liquid with an aromatic odor. It is produced by the destructive distillation of coal, and may also be formed during processing of fossil fuels, such as coke production and coal gasification. Limited data indicate that 2,3-benzofuran may partition to soils and sediments from water, but the information available is insufficient to predict the environmental fate of this compound. Substantial bioconcentration in aquatic organisms is not expected based on the physical/chemical properties of 2,3-benzofuran. 

Stephen Hales, George Dixon, and Bishop Watson afterward made similar experiments. Professor Minckelers of tile University of Louvain distilled gas from powdered coal and lighted his lecture room with it in 1784—85 ( 26). In 1792 William Murdock lighted his house at Redruth, Cornwall, with gas made by the destructive distillation of coal (28). 

By passing fhts through red>hot tubes, fi. By the destructive distillation of coal. 

Coal tar is the condensation product obtained by cooling to approximately ambient temperature, the gas evolved in the destructive distillation of coal. It is a black viscous liquid denser than water and composed primarily of a complex mixture of condensed ring aromatic hydrocarbons. It may contain phenolic compounds, aromatic nitrogen bases and their alkyl derivatives, and paraffinic and olefinic hydrocarbons. Coal-tar pitch is the residue from the distillation of coal tar. It is a black solid having a softening point of 30—180°C (86—359°F). 

It is incorrect to refer to bitumen as tar or pitch. Although the word tar is somewhat descriptive of the black bituminous material, it is best to avoid its use in referring to natural materials. More correctly, the name tar is usually applied to the heavy product remaining after the destructive distillation of coal (qv) or other organic matter. Pitch is the distillation residue of the various types of tar (see Tar AND PITCH). 

Until the 1940s light oil obtained from the destructive distillation of coal was the principal source of benzene. Except for part of the Wodd War II period, the quantity of benzene produced by the coal carbonization industry was sufficient to supply the demand even when a large portion of benzene was used for gasoline blending. 

The recorded chronology of the coal-to-gas conversion technology began in 1670 when a clergyman, John Clayton, in Wakefield, Yorkshire, produced in the laboratory a luminous gas by destructive distillation of coal (12). At the same time, experiments were also underway elsewhere to carbonize coal to produce coke, but the process was not practical on any significant scale until 1730 (12). In 1792, coal was distilled in an iron retort by a Scottish engineer, who used the by-product gas to illuminate his home (13). 

Sodium, potassium, barium, or calcium thiocyanate may be made by reaction of sulfur and the corresponding cyanide by heating to fusion. Ammonium thiocyanate (plus ammonium sulfide) may be made by reaction of ammonia and carbon disulfide, a reaction which probably accounts for tlie presence of ammonium thiocyanate in the products of the destructive distillation of coal. This reaction corresponds to the formation of ammonium evanate from ammonia and carbon dioxide. 

None of the preceding methods would be suitable for industrial use. For many years the bulk of the ammonia produced commercially was obtained as a by-product of the destructive distillation of coal. More recently, however, processes that are far more satisfactory have been devised. 

Manufactured gases are those obtained by destructive distillation of coal, by the thermal decomposition of oil, or by the reactions of steam passing through a bed of heated coal or coke. Prior to the development of large natural gas reserves, manufactured gas was used widely for illumination in the gaslight era of the United States. 

An impure form of carbon obtained by destructive distillation of coal or petroleum. 

Illuminating Gas is formed by the destructive distillation of coal. It is a mixture of many gases, and its composition varies with the coal employed. The constituents are divided into three classes, viz. illuminants, diluents, and impurities. The first class contains, among other gases, ethylene and acetylene. Marsh gas, hydrogen, and carbon monoxide, all of which burn with a feeble — non-yellow — flame, are the most common diluents. The common impurities are carbon dioxide, hydrogen sulphide, and ammonia some of these, however, are entirely removed from the purified gas. Illuminating gas prepared as above is often called coal gas. 

Benzene.—What then is benzene, the mother substance of this large division of organic compounds which as we shall find are unsurpassed in their application to the industries and to daily life When coal gas is made by the destructive distillation of coal the products in the first place are. probably water, methane and ammonia. These being subjected to considerable heat result in the formation of numerous more complicated compounds. The gaseous products, consisting of methane, hydrogen, etc., constitute crude illuminating gas. The solid... 

Coal tar is a viscous liquid mixture of hydrocarbon compounds, derived along with coke, from the destructive distillation of coal in coking ovens. Coal tar itself may be subjected to distillation, a process that separates groups of the components of coal tar from groups of others. The substances derived from this process are often called coal tar distillates . 

Until quite recently, practically the total supply of ammonia was obtained as a by-product in the destructive distillation of coal for the purpose of making illuminating gas, much also being produced by coke ovens, and the processes now worked for the gasification of coal, peat, oil-shale, etc. 

Derivation (1) Ammoniacal vapors from destructive distillation of coal react with sulfuric acid, followed by crystallization and drying. (2) Synthetic... 

I jii- synthetic fibres differ from those classified as regenerated because the giant molecules of whiih the are composed are synthesized from quite simple monomers, t he raw mater.als are not naturally occurring and are very often derived from by-products a the destructive distillation of coal or the cracking of petroleum. 

Coal gas for illumination — and later for heating — was produced by the destructive distillation of coal and resulted in the production of large volumes... 

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