Extended thermal stage sulfur recovery process

Patent metadata

Field	Value
Publication number	US-10246329-B1
Application number	US-201715815980-A
Country	US
Kind code	B1
Filing date	Nov 17, 2017
Priority date	Nov 17, 2017
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A process for recovering sulfur in a sulfur recovery unit comprising the steps of reacting hydrogen sulfide and oxygen in the reaction furnace at a minimum reaction temperature to produce a reaction effluent; reducing the temperature of the reaction effluent from the minimum reaction temperature to a boiler section outlet temperature to produce a cooled effluent, the cooled effluent comprises hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants; reacting the hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants in the catalytic extension to produce a boiler catalytic effluent; reducing the boiler catalytic effluent temperature such that the elemental sulfur condenses to form liquid sulfur and a gases stream; reacting the hydrogen sulfide and sulfur-containing contaminants with the oxygen to produce an oxidizer outlet stream comprises sulfur dioxide; and separating the sulfur dioxide in the scrubbing unit to produce a recycle stream and an effluent gases, the recycle stream comprises sulfur dioxide.

First claim

What is claimed is:

1. A process for recovering sulfur in a sulfur recovery unit, the process comprising the steps of:
introducing an acid gas feed to a reaction furnace, where the acid gas feed comprises hydrogen sulfide;
introducing a fuel gas to the reaction furnace;
introducing air feed to the reaction furnace, where the air feed comprises oxygen;
reacting the hydrogen sulfide and oxygen in the reaction furnace at a minimum reaction temperature to produce a reaction effluent, where the reaction effluent comprises elemental sulfur and sulfur dioxide, where the reaction effluent is at the minimum reaction temperature;
introducing the reaction effluent to a wasteheat stage of an extended boiler stage;
reducing the temperature of the reaction effluent from the minimum reaction temperature to a boiler section outlet temperature to produce a cooled effluent, where the cooled effluent comprises hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants, where the temperature of the reaction effluent is reduced by capturing heat energy;
introducing the cooled effluent to a catalytic extension of the extended boiler stage, where the catalytic extension comprises a catalyst, where the catalytic extension has a gross hourly space velocity between 3000 h−1 and 6000 h−1;
reacting the hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants in the catalytic extension to produce a boiler catalytic effluent, where the boiler catalytic effluent comprises elemental sulfur, where the boiler catalytic effluent is at a boiler catalytic effluent temperature;
introducing the boiler catalytic effluent to a condenser, where the boiler catalytic effluent comprises elemental sulfur;
reducing the boiler catalytic effluent temperature such that the elemental sulfur condenses to form liquid sulfur and a gases stream;
introducing the gases stream to a thermal oxidizer, where the gases stream comprises hydrogen sulfide and sulfur-containing contaminants;
introducing an air stream to the thermal oxidizer, where the air stream comprises oxygen;
reacting the hydrogen sulfide and sulfur-containing contaminants with the oxygen to produce an oxidizer outlet stream, where the oxidizer outlet stream comprises sulfur dioxide;
introducing the oxidizer outlet stream to a scrubbing unit; and
separating the sulfur dioxide in the scrubbing unit to produce a recycle stream and an effluent gases, where the recycle stream comprises sulfur dioxide.

2. The process of claim 1 , further comprises the step of introducing the recycle stream to the reaction furnace.

3. The process of claim 1 , further comprises the steps of:
introducing a boiler feed water to the extended boiler stage; and
increasing the temperature of the boiler feed water to produce a high pressure steam, where the heat captured from the reaction effluent is used to increase the temperature of the boiler feed water.

4. The process of claim 1 , where the minimum reaction temperature is between 850 deg C. and 1250 deg C.

5. The process of claim 1 , where the boiler section outlet temperature is between 148 deg C. and 254 deg C.

6. The process of claim 1 , where the boiler catalytic effluent temperature is between 250 deg C. and 400 deg C.

7. The process of claim 1 , where the catalyst is titania extrudate.

8. The process of claim 1 , where an overall conversion of sulfur compounds to elemental sulfur is greater than 99.9 mol %.

9. The process of claim 1 , further comprising the steps of:
analyzing a composition of the gases stream in a tail gas analyzer; and
adjusting a flow rate of the air feed based on the composition of the gases stream to maintain a stoichiometric ratio of hydrogen sulfide to sulfur dioxide of 2:1.

10. The process of claim 1 , further comprising the steps of:
measuring the minimum reaction temperature in the reaction furnace with a temperature sensor; and
adjusting a flow rate of the fuel gas to maintain the minimum reaction temperature.

Assignees

• Saudi Arabian Oil Co

Inventors

• O'Connell John P

Classifications

• B01D53/523

  Mixtures of hydrogen sulfide and sulfur oxides · CPC title

• C01B17/0426 Primary

  characterised by the catalytic conversion · CPC title

• C01B17/16

  Hydrogen sulfides · CPC title

• B01J12/007

  in the presence of catalytically active bodies, e.g. porous plates · CPC title

• C01B17/0404

  by processes comprising a dry catalytic conversion of hydrogen sulfide-containing gases, e.g. the Claus process · CPC title