Method for producing hydrocyanic acid (HCN)

Abstract

The invention relates to a method for preparing hydrogen cyanide according to andrussow process, which is carried out by reacting methane gas, ammonia gas and oxygen-containing gas at rising temperature on catalyst. Oxygen has a volume proportion (O<2> / (O<2>+N<2>) of 0.2 to 1.0 corresponding to total volume of nitrogen and oxygen, and the reaction is carried out by adopting mixture of incombustible reactant gas.

Description

technical field [0001] The present invention relates to improvements in the Andrussow process for the preparation of hydrogen cyanide (HCN). Background technique [0002] The synthesis of hydrogen cyanide (hydrocyanic acid) according to the Andrussow method is described in Ullmann's Encyclopedia of Industrial Chemistry, Vol. 8, VCH Verlagsgesellschaft, Weinheim 1987, pp. 161-162. A reactant gas mixture, usually comprising methane or a methane-containing natural gas stream, ammonia and oxygen, is led through the catalyst mesh in a reactor and reacted at a temperature of about 1000°C. The necessary oxygen is usually used in the form of air. The catalyst mesh is composed of platinum or a platinum alloy. The composition of the reactant gas mixture roughly corresponds to the stoichiometry of the overall reaction equation proceeding exothermically as follows: [0003] CH 4 +NH 3 +3 / 2 O 2 →HCN+3H 2 OdHr=-473.9kJ. [0004] The outgoing reaction gas contains product HCN, unco...

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Problems solved by technology

[0022] Risk of localized temperature peaks, which can damage the catalyst mesh

[0023] 2. Increased oxygen supply at the catalyst leads to enhanced NH 3 Oxidized to N 2 and thus lead to a based on the NH used 3 Calculated HCN yield decreased

[0025] 4. Increased catalyst web temperature may occur through oxygen enrichment in the reactant gas, which leads to faster destruction and deactivation of the catalyst

[0026] 5. The solution to existing disadvantages by employing specially constructed reactors (WO97 / 09273) requires high investment and is not suitable for cost-effectively improving the performance of existing plants

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