Acetylene from coal

Avco An electric arc process for making acetylene from coal and hydrogen. The arc in hydrogen is rotated by a magnetic field in order to spread it out and thus make better contact with the coal passing through. Developed by V. J. Krukonis at the Avco Corporation in the early 1970s with support from the U.S. Office of Coal Research Piloted at the rate of 55 kg/hr but not yet commercialized. 

In the United States. AVCO (Wulff Acetylene Company, in cooperation with CAF (General Anilin and Film Co. has also built an experimental pilot plant to manufacture acetylene from coal with a high volatile matter content. The coal is fluidized in hydrogen produced in the process, and introduced into an electric arc. The cracked gases arc quenched by a hydrocarbon stream. The effluent is rid of coal particles, compressed to 0.3, 10 Pa absolute, treated with N-methyipyrroIidone to remove HjS and HCN, and... 

When Ar + H2 mixture was used as the principal arc gas a maximum C2H2 yield of 74% by wt on a C basis was found (Table 12). This is the highest yield of acetylene from coal yet reported. It appears that the penetration and hydrogenation of the coal-carrier gas stream, which was injected axially rather than radially into the plasma stream is a critical factor in the acetylene production. 

Thermal Plasma Jet Pyrolysis of Coal in Argon, Hydrogen, and Their Mixtures Plasma Jet Production of Acetylene from Coal... 

Chakravartty, S.H., Dutta, D, Lahiri, A. (1976), Reaction of Coals under Plasma Conditions Direct Production of Acetylene from Coal, Energy, vol. 56, p. 43. 

Reppe Reactions of acetylene (from coal) with CO and water or alcohols to acrylic acid and esters catalyzed by transition metal carbonyls... 

Acetylene was discovered m 1836 by Edmund Davy and characterized by the French chemist P E M Berthelot m 1862 It did not command much attention until its large scale preparation from calcium carbide m the last decade of the nineteenth century stim ulated interest m industrial applications In the first stage of that synthesis limestone and coke a material rich m elemental carbon obtained from coal are heated m an electric furnace to form calcium carbide... 

R. J. Tedeschi, Acetylene Based Chemicals from Coal and Other Natural Resources, Marcel Dekker, Inc., New York, 1982. 

Acetylene traditionally has been made from coal (coke) via the calcium carbide process. However, laboratory and bench-scale experiments have demonstrated the technical feasibiUty of producing the acetylene by the direct pyrolysis of coal. Researchers in Great Britain (24,28), India (25), and Japan (27) reported appreciable yields of acetylene from the pyrolysis of coal in a hydrogen-enhanced argon plasma. In subsequent work (29), it was shown that the yields could be dramatically increased through the use of a pure hydrogen plasma. 

With each succeeding year in the 1950s and 1960s there was a swing away from coal and vegetable sources of raw materials towards petroleum. Today such products as terephthalic acid, styrene, benzene, formaldehyde, vinyl acetate and acrylonitrile are produced from petroleum sources. Large industrial concerns that had been built on acetylene chemistry became based on petrochemicals whilst coal tar is no longer an indispensable source of aromatics. 

The Chemistry and Technology of Petroleum, James G. Speight The Desulfurization of Heavy Oils and Residua, James G. Speight Catalysis of Organic Reactions, edited by William R. Moser Acetylene-Based Chemicals from Coal and Other Natural Resources, Robert J. Tedeschi... 

Pyridine and its derivatives are technically-important fine chemicals. Their isolation from coal tar is decreasing, whereas their manufacture by synthetic methods has increased rapidly. The classical pathways to pyridine have been discussed by Abramovitch (74HC14-1-4). Many of them rely on the reaction of aldehydes or ketones with ammonia in the vapor phase. However, the condensation processes used suffer from unsatisfactory selectivity. Using soluble organocobalt catalysts of the type [YCoL] allows pyridine and a wide range of 2-substituted derivatives to be prepared selectively and in one step from acetylene and the appropriate cyano compound [Eq.(l)]. 

Another two-carbon feedstock is acetylene. Acetylene is typically obtained from coal by converting coke calcium carbide and then treating the calcium carbide with water. As shown in Figure 17.3, a number of important monomers can be made from acetylene. Even so, because of the abundance of other feedstocks from petroleum reserves, only some of the routes shown in Figure 17.3 are widely used. 

Acetylene, which is produced from coal or natural gas, is burned with oxygen in oxyacetylene torches for welding. This mixture of gases can reach temperatures of 5,072°F (2,800°C), which is hot enough to melt steel. 

Twenty-five years ago the only oxygenated aliphatics produced in important quantities were ethyl and n-butyl alcohols and acetone made by the fermentation of molasses and grain, glycerol made from fats and oils, and methanol and acetic acid made by the pyrolysis of wood. In 1927 the production of acetic acid (from acetylene) and methanol (from synthesis gas) was begun, both made fundamentally from coal. All these oxygenated products are still made from the old raw materials by the same or similar processes, but the amount so made has changed very little in the past quarter century. Nearly all the tremendous growth in the production of this class of compounds has come from petroleum hydrocarbons. 

Table III shows that gaseous product from the irradiation of less than 10 micron coal (micronized) showed higher methane and lower acetylene than coal from the cube. Other particle sizes will have to be investigated to determine if particle size is a parameter for maximum acetylene production.

The rates of heating and cooling associated with electric arcs are especially favorable for reactions which require rapid heating followed by quenching. For example, an arc process has been particularly successful for producing, on an industrial scale, acetylene from hydrocarbons (2). Brief references have been made in some of the early arc work to using coal as the raw material (6, 7, 14). 

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