Process for sulfur removal from refinery off gas
AssigneePraxair Technology, Inc.
InventorsMinish Mahendra Shah, Raymond Francis Drnevich, Vasilis Papavassiliou
Life of this patent
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Abstract
Organic sulfur compounds contained in refinery off gas streams having either high ort low concentrations of olefins are converted to hydrogen sulfides which can be then be removed using conventional amine treating systems. The process uses a catalytic reactor with or without a hydrotreater depending on the olefin concentration of the off gas stream. The catalytic reactor operates in a hydrogenation mode or an oxidation mode to convert a majority of organic sulfur compounds into hydrogen sulfides.
Claims20
A process for removal of organic sulfur compounds from multiple refinery off gas streams containing at least olefins and sulfur compounds including H2S and organic sulfur compounds, wherein a first off gas feed stream contains a high concentration of olefins and a second off gas feed stream contains a low concentration of olefins, the process comprising:
- a) feeding the first feed stream to an amine absorber to remove at least part of the H2S to produce a first H2S depleted stream;
- b) feeding the second feed stream to an amine absorber to remove at least part of the H2S to produce a second H2S depleted stream;
- c) splitting the first H2S depleted stream into a first split stream and a second split stream;
- d) feeding the first split stream into a catalytic reactor at a temperature of between 340° C. and 450° C. to convert a majority of the organic sulfur compounds to H2S at the pressure employed and removing a hot first organic sulfur depleted stream from the catalytic reactor;
- e) combining the second split stream and second H2S depleted stream are mixed in quantities such that the resulting combined stream is fed into a hydrotreater and maintains the temperature of the hydrotreater to between about 340° C. and 450° C. at the pressure employed and converting the organic sulfur compounds into H2S;
- f) removing a second organic sulfur depleted stream from the hydrotreater;
- g) combining the first organic sulfur depleted stream and the second organic sulfur depleted stream to form a combined organic sulfur depleted stream;
- h) cooling the combined organic sulfur depleted stream;
- and
- i) feeding the cooled combined organic sulfur depleted stream to an amine sulfur removal system to remove the H2S and produce a product gas stream.
A process for the removal of H2S and organic sulfur compounds from a refinery off gas feed stream containing at least hydrogen, and a high concentration of olefins comprising:
- a) removing at least a portion of the H2S from the feed stream by passing the feed stream through an amine absorber to produce a H2S depleted stream;
- b) feeding the H2S depleted stream into a catalytic reactor at a temperature between 340° C. and 450° C. to convert a majority of the organic sulfur compounds to H2S at the pressure employed;
- c) cooling the product gas stream exiting the catalytic reactor;
- and
- d) feeding the cooled product gas stream to an amine sulfur removal system to remove the H2S and produce a product gas stream.
A process for the removal of H2S and organic sulfur compounds from a refinery off gas feed stream containing hydrogen, carbon oxides and olefins comprising:
- a) removing at least a portion of the H2S from the feed stream by passing the feed stream through an amine absorber to produce a H2S depleted stream;
- b) determining the olefin concentration of the feed stream or H2S depleted stream;
- c) determining the process flow based on the concentration of olefins in the feed stream or the H2S depleted stream such that;
- (I) when the olefin concentration is determined to be 3% or less,
- (i) feeding a first portion of the H2S depleted stream with the addition of oxygen into a catalytic reactor to maintain the temperature of the catalytic reaction between 340° C. and 450° C. at the pressures employed and convert a majority of the organic sulfur compounds to H2S;
- (ii) feeding a second portion of the H2S depleted stream into a hot effluent stream exiting the catalytic reactor;
- (iii) feeding the hot effluent stream into a hydrotreater and maintaining a temperature of between 340° C. and 450° C. to convert a majority of the organic sulfur compounds to H2S and produce an H2S rich product gas stream;
- (iv) cooling the H2S rich product gas stream exiting the hydrotreater;
- and
- (v) feeding the cooled H2S rich product gas stream to an amine sulfur removal system to remove the H2S and produce a sulfur depleted product stream;
- or
- (II) when the olefin concentration is determined to be 5% or greater,
- (i) feeding the H2S depleted stream into a catalytic reactor and maintaining the temperature to between about 340° C. and 450° C. to convert a majority of the organic sulfur compounds to H2S at the pressures employed and produce a product gas stream;
- (ii) directing the product gas stream to bypass the hydrotreater, (iii) cooling the product gas stream;
- and (iv) feeding the cooled product gas stream to an amine sulfur removal system to remove the H2S to produce a sulfur depleted product stream.
A process for the removal of H2S and organic sulfur compounds from a refinery off gas feed stream containing at least hydrogen and a low concentration of olefins wherein the hydrogen to olefin molar ratio is greater than 0.5, comprising:
- a) removing at least a portion of the H2S from the feed stream by passing the feed stream through an amine absorber to produce a H2S depleted stream;
- b) feeding the H2S depleted stream into a catalytic reactor at a temperature between 340° C. and 450° C. to convert a majority of the organic sulfur compounds to H2S at the pressure employed;
- c) cooling the product gas stream exiting the catalytic reactor;
- and
- d) feeding the cooled product gas stream to an amine sulfur removal system to remove the H2S and produce a product gas stream.
Dependencies are inferred from the claim text.