Acetylene from hydrocarbons

In summary, the bad features of partial combustion processes are the cost of oxygen and the dilution of the cracked gases with combustion products. Flame stability is always a potential problem. These features are more than offset by the inherent simplicity of the operation, which is the reason that partial combustion is the predominant process for manufacturing acetylene from hydrocarbons. 

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). 

FIG. 19-13 Noncatalytic gas-phase reactions, (a) Steam cracking of light hydrocarbons in a tubular fired heater, (b) Pebble heater for the fixation of nitrogen from air. (c) Flame reactor for the production of acetylene from hydrocarbon gases or naphthas. [Patton, Grubb, and Stephenson, Pet. Ref. 37(11) 180 (1958).] d Flame reactor for acetylene from light hydrocarbons (BASF), (e) Temperature profiles in a flame reactor for acetylene (Ullmann Encyclopadie der Technischen Chemie, vol. 3, Verlag Chemie, 1973, p. 335). 

Industrial processes for the uianulacture of acetylene from hydrocarbons are distin guished by the heating technique. 

Miller, S. A., Acetylene. Its Properties, Manufacture and Uses, 1, Ernest Benn Limited. Loodoo (1965). Tetboth, J. A., Acetylene from hydrocarbons , IP Rev. (Oct 1967). 

Schoch, E. P., et al., Acetylene from Hydrocarbons, University of Texas... 

In the past several years, considerable effort has been directed to the investigation of the production of acetylene from hydrocarbons (Reaction 1). 

Duncan, D.A. (1978) Acetylene from Hydrocarbons , in M. Grayson and D. Eckroth (eds.), Kirk-Othmer Encyclopedia of Chemical Technology, 3rd Ed., Vol. 1, John Wiley Sons, Inc., New York, NY, pp. 211-37. 

Acetylene Derived from Hydrocarbons The analysis of purified hydrocarbon-derived acetylene is primarily concerned with the determination of other unsaturated hydrocarbons and iaert gases. Besides chemical analysis, physical analytical methods are employed such as gas chromatography, ir, uv, and mass spectroscopy. In iadustrial practice, gas chromatography is the most widely used tool for the analysis of acetylene. Satisfactory separation of acetylene from its impurities can be achieved usiag 50—80 mesh Porapak N programmed from 50—100°C at 4°C per minute. 

Although acetylene production in Japan and Eastern Europe is stiU based on the calcium carbide process, the large producers in the United States and Western Europe now rely on hydrocarbons as the feedstock. Now more than 80% of the acetylene produced in the United States and Western Europe is derived from hydrocarbons, mainly natural gas or as a coproduct in the production of ethylene. In Russia about 40% of the acetylene produced is from natural gas. 

Vinyl acetate (ethenyl acetate) is produced in the vapor-phase reaction at 180—200°C of acetylene and acetic acid over a cadmium, 2inc, or mercury acetate catalyst. However, the palladium-cataly2ed reaction of ethylene and acetic acid has displaced most of the commercial acetylene-based units (see Acetylene-DERIVED chemicals Vinyl polymers). Current production is dependent on the use of low cost by-product acetylene from ethylene plants or from low cost hydrocarbon feeds. 

Carbide lime is a waste lime hydrate by-product from the generation of acetylene from calcium carbide and may occur as a wet sludge or dry powder of widely varying purity and particle size. It is gray and has the pungent odor associated with acetylene (see Hydrocarbons, acetylene). 

Tetrachloroethylene was first prepared ia 1821 by Faraday by thermal decomposition of hexachloroethane. Tetrachloroethylene is typically produced as a coproduct with either trichloroethylene or carbon tetrachloride from hydrocarbons, partially chloriaated hydrocarbons, and chlorine. Although production of tetrachloroethylene and trichloroethylene from acetylene was once the dominant process, it is now obsolete because of the high cost of acetylene. Demand for tetrachloroethylene peaked ia the 1980s. The decline ia demand can be attributed to use of tighter equipment and solvent recovery ia the dry-cleaning and metal cleaning iadustries and the phaseout of CFG 113 (trichlorotrifluoroethane) under the Montreal Protocol. 

Inert combustion gases are injected directly into the reacting stream in flame reactors. Figures 23-22 and 22>-22d show two such devices used for maldng acetylene from light hydrocarbons and naphthas Fig. 23-22 shows a temperature profile, reaction times in ms. 

The first stage does the bulk of the separation, and the second is used to remove other dienes and acetylenes from the isoprene. In the extractive distillation tower of each stage, the ACN solvent is introduced near the top, and being the highest boiling component, travels downward. The effective relative volatility of the less unsaturated hydrocarbons is increased with respect to isoprene. Thus most of the impurities go overhead and the isoprene is carried down with the solvent. 

Belay N, L Daniels (1987) Production of ethane, ethylene and acetylene from halogenated hydrocarbons by methanogenic bacteria. Appl Environ Microbiol 53 1604-1610. 

Aq us mixtures of formaldehyde, acetylene from lower hydrocarbons and most gases. 

Formaldehyde from water and acetylene from lower hydrocarbons. Gases, polar materials such as water, alcohols, aldehydes and glycols. 

KLP [Dow K Catalyst liquid phase] A selective hydrogenation process for removing acetylenes from cmde C4 hydrocarbons from ethylene cracking, with no loss of butadiene. The catalyst is based on either copper metal or alumina. Developed by Dow Chemical Company and first commercialized at its plant in Temeuzen, The Netherlands. The KLP licensing business was sold to UOP in 1991. 

SBA-Kellogg A pyrolytic process for making ethylene and acetylene from saturated hydrocarbon gases, similar to the Hoechst HTP process but with the addition of steam which increases the yield of C2 gases. 

From Hydrocarbon Oils.—While the decomposition of acetylene is attended with the evolution of heat, most other hydrocarbon gases absorb heat when they decompose into their constituents consequently, to produce hydrogen from other hydrocarbon gas or volatilised hydrocarbon oils, it is necessary to supply heat during the process. 

---