Patent GB-368164-A (GB)
Title: Improvements in or relating to the manufacture of acetylene from hydrocarbons by means of an electric arc
IPC: C07C2/80
Filed: 1931-06-08
Abstract: Hydrogen is produced as a by-product in the manufacture of acetylene by treating hydrocarbons or gases containing them in an electric arc in which the current density with respect to at least one of the electrodes is maintained in the neighbourhood of that at which loss of substance of the electrodes can be detected.  In an example the process is applied to the treatment of methane. Other starting materials specified are ethylene or other unsaturated hydrocarbons or mixtures thereof with saturated hydrocarbons, mixtures of hydrocarbons with indifferent gases, liquid hydrocarbons of low boiling point such as benzine or benzene, also naphthalene, particularly when diluted with methane or hydrogen.  Specification 195,239, [Class 1 (i), Chemical processes &c.], is referred to.ALSO:Acetylene is manufactured by subjecting hydrocarbons or gases containing them to the action of an electric arc in which the current density with respect to at least one of the electrodes is maintained in the neighbourhood of that at which loss of substance of the electrodes can be detected.  The process may be carried out in a cyclic manner, the gases or vapours being caused to circulate by means of a blower in a continuous tubular system constructed, for example, of iron.  Preferably one of the electrodes is tubular and serves for the continuous withdrawal of a portion of the gas, whilst fresh gas is introduced through an inlet tube or through the other electrode if this is also tubular. The optimum conditions are ascertained by determining the current density at which loss of substance can be detected, maintaining it in the neighbourhood of this value, circulating the gas with a high velocity while connecting the inlet tube to a source of gas, withdrawing increasing quantities of gas until the desired concentration of acetylene is obtained and then further increasing the rate of withdrawal until the concentration of acetylene begins to fall substantially.  It is sometimes desirable to use electrodes containing added substances which vaporize in the arc and mix with the gas, or to introduce substances into the gas in finely divided form, the substances in each case being such as increase the ionization of the gases in the arc.  When using a vaporized or atomized hydrocarbon it may be necessary to heat the circulatory system, e.g. by means of a steam jacket, or it may be sufficient merely to insulate the system against loss of heat. The process may be conducted at atmospheric, lowered or preferably raised pressures.  The electrodes may be of carbon, or of metals or carbides, the coating of soot which forms rendering the latter practically equivalent to carbon electrodes.  Instead of a single arc, several arcs arranged in series or parallel may be employed. In an example the process is applied to the treatment of methane, the gas produced consisting of acetylene, hydrogen, unchanged methane and a little ethylene.  Other starting materials specified are ethylene or other unsaturated hydrocarbons or mixtures thereof with saturated hydrocarbons, mixtures of hydrocarbons with indifferent gases, or liquid hydrocarbons of low boiling point such as benzine or benzene, also naphthalene, particularly when diluted with methane or hydrogen.  Specification 195,239, [Class 1 (i), Chemical processes &c.], is referred to.