Abstract:
The invention provides an oxygen Andrussow process for production of hydrogen cyanide from a methane-containing feedstock such as natural gas in the presence of oxygen and ammonia over a platinum catalyst, wherein the production of byproduct organonitrile impurities, such as acrylonitrile, is reduced. Limiting the content of C 2 + hydrocarbons in the methane feedstock in the oxygen Andrussow process, in contrast to the air Andrussow process, has been found to reduce formation of organonitriles, such as acrylonitrile. The organonitrile impurities can require additional processing for removal, cause fouling of equipment, and can also contribute to hydrogen cyanide polymerization. Reduction of C 2 + hydrocarbon levels to less than 2 wt%, or 1 wt%, or less than 0.1 wt%, in the methane can provide an improved yield of higher purity HCN. Reduction of C 2 + hydrocarbon levels also solves the problem of polymer buildup in process equipment, reducing downtime required for cleaning when higher C 2 + hydrocarbon levels are present in the reaction feed.
Abstract:
The invention provides an oxygen Andrussow process for production of hydrogen cyanide from a methane-containing feedstock such as natural gas in the presence of oxygen and ammonia over a platinum catalyst, wherein the production of byproduct organonitrile impurities, such as acrylonitrile, is reduced. Limiting the content of C 2 + hydrocarbons in the methane feedstock in the oxygen Andrussow process, in contrast to the air Andrussow process, has been found to reduce formation of organonitriles, such as acrylonitrile. The organonitrile impurities can require additional processing for removal, cause fouling of equipment, and can also contribute to hydrogen cyanide polymerization. Reduction of C 2 + hydrocarbon levels to less than 2 wt%, or 1 wt%, or less than 0.1 wt%, in the methane can provide an improved yield of higher purity HCN. Reduction of C 2 + hydrocarbon levels also solves the problem of polymer buildup in process equipment, reducing downtime required for cleaning when higher C 2 + hydrocarbon levels are present in the reaction feed.
Abstract:
A method and a system for recovering hydrogen from a process for making hydrogen cyanide are described herein. In the method, hydrogen is recovered from a gaseous waste stream of an Andrussow process. The method comprises the following steps: (a) adjusting a reaction mixture comprising methane, ammonia and oxygen to provide the reaction mixture with sufficient oxygen to generate a gaseous waste stream that has at least 40% hydrogen after removal of ammonia and recovery of hydrogen cyanide; and(b) removing components from the gaseous waste stream to generate recovered hydrogen.
Abstract:
The system and methods described herein solve problems of inaccurate flow control, loss of optimum reactant gas feed ratios, and the associated inefficiencies brought on by variable humidity in reactant feedstream gases during production of hydrogen cyanide by an Andrussow process.
Abstract:
The present invention relates to an improved process for producing hydrogen cyanide involving a heat exchanger comprising a plurality of tubes, wherein each of the plurality of tubes comprises a ceramic ferrule extending through the entrance of the tube, each ferrule comprising an insulation layer surrounding at least a portion of the ferrule, and one or more washers, wherein at least one of the one or more washers surrounds the ferrule above the entrance of the tube, wherein the ceramic ferrule is spaced apart from the tube. It further relates to a reaction apparatus for producing hydrogen cyanide involving a heat exchanger comprising a plurality of tubes, wherein each of the plurality of tubes comprises a ceramic ferrule extending through the entrance of the tube, each ferrule comprising an insulation layer surrounding at least a portion of the ferrule, and one or more washers, wherein at least one of the one or more washers surrounds the ferrule above the entrance of the tube, wherein the ceramic ferrule is spaced apart from the tube. It further relates to the heat exchanger for use in this improved process and reaction apparatus.
Abstract:
Processes and systems for the production of hydrogen cyanide via the Andrussow process are described. A reaction zone, wherein oxygen, ammonia, and methane can be allowed to react in the presence of a catalyst comprising platinum to provide hydrogen cyanide. A desulfurization zone, wherein a feed stream comprising sulfur and at least one of the oxygen, the ammonia, and the methane can be contacted with a desulfurization material to produce a sulfur- reduced feed stream that is provided to the reaction zone. In an example, the desulfurization material includes zinc oxide.