BMA process

The BMA method ( hydrocyanic acid from methane and ammonia) is one of Degussa (now Evonik Degussa) developed process for preparing hydrocyanic acid directly from ammonia and methane without oxygen is used:

Process principle

Methane and ammonia are fed through a tube which is coated with platinum as a catalyst. The tube serves as a heat exchanger through which the reaction heat is transferred, which is required for the highly endothermic reaction. The temperature inside the tube is approx 1200 ° C. The resulting gas mixture contains about 23 vol - % HCN, 72 volume - %, H2 and unconverted ammonia in smaller proportions, nitrogen and methane.

From the gaseous ammonia reaction product is first separated off by chemisorption of an acid (aqueous sulfuric or phosphoric acid ). Subsequently, the hydrogen cyanide will be absorbed in cold water to separate them from the rest of inert gases (H2, CH4, and N2). The thereby formed mixture of HCN and water is separated by distillation, where HCN is obtained as the top product and the water is returned to the absorption.

History

Having obtained in laboratory experiments in a heated tube yields relative to 90 % on ammonia and methane, there were the first signs of a technical realization during the Second World War the Germans cyanamide plants in Piesteritz. The development was continued after 1949 within the Degussa, it turned out, however, that the fundamentals of the method and the means needed to be revised to its technical realization.

After extensive studies in the laboratory under the direction of E. Wagner 1951 commenced with the testing of a gas-fired furnace technology. 1954, the work so far advanced that a pilot plant could be set up with a capacity of 6.5 t / month plans and. The furnace of this system was developed in cooperation with the companies Heinrich Koppers GmbH and Wistra furnace construction company ltd. In long-term tests that stretched continuously over 6 months, materials, construction elements and the catalyst specially developed were examined in detail. In the spring of 1956 a plant with a capacity of 100 t / month was planned and built in 1957 and put into operation.

Technical significance

The BMA method is technically only of secondary importance. In addition, a method is cleaved with formamide in water and hydrogen cyanide, and applied BASF exists. The production of hydrocyanic acid the Andrussow process is most often used, especially for larger quantities. The Andrussow process is different from the BMA process is that oxygen is introduced into the reactor. The heat of reaction for the formation of hydrocyanic acid is ( partially and ammonia ) produced by the combustion of methane in the reaction mixture itself, so that a heat exchanger is required.

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