Method of making hydrocyanic acid using a mass spectrometer control system
A method for making hydrocyanic acid in which the product of the reaction of methane and ammonia is analyzed using a mass spectrometer whose output is used to control the feed ratios of methane and ammonia to the reactor to control product quality.
1 . A continuous method for making HCN over a predetermined time period, comprising:
(1) feeding air, natural gas and ammonia to a reactor that contains a catalyst comprising a platinum group metal to produce a product gas that comprises HCN, methane and one or more saturated or unsaturated C 2 -C 5 nitrile compounds, the natural gas and air being fed to the reactor at a preselected ratio;
(2) withdrawing a sample of the product gas and introducing it into a mass spectrometer to measure in less than 10 seconds the amount of at least one compound selected from the group consisting of methane and saturated or unsaturated C 2 -C 5 nitrile compounds, in the sample;
(3) determining whether the amount of the at least one compound measured in step (2) exceeds a predetermined acceptable limit therefor, and, if so:
(4) changing the ratio of natural gas and air to a ratio different from the preselected ratio;
(5) withdrawing a new sample of the product gas and introducing it into the mass spectrometer to measure in the new sample in less than 10 seconds the amount of the at least one compound measured in step (2); and
6) optionally repeating steps (1) to (5) until the amount of at least one of the compounds selected for measurement in steps (2) and (5) in the sample is below its predetermined acceptable limit; and
(7) repeating steps (1) to (6) over the entire predetermined time period.
2 . A method as in claim 1 wherein the time for measurement using mass spectrometer in steps (2) and (5) is less than 6 seconds.