US 2026/0077296 A1Published application

Complete conversion of sulfur dioxide to sulfuric acid by aqueous acid absorption

AssigneeSaudi Arabian Oil Company

InventorsGuillaume Robert Jean-Francois Raynel, Sebastien A. Duval, Feras Hamad, Khadijah Ghazi Alshadly, Faisal Ibrahim Jassim

Life of this patent

Estimating the term…

patentgrep

Loading patent…

Abstract

The technology includes a method for removing sulfur dioxide (SO2) from a gas stream, where SO2 gas is contacted by a diluted sulfuric acid (H2SO4) stream and absorption takes place in a quench tower. The dissolved SO2 reacts with the excess of oxygen in the gas stream, where the oxidation results in the formation of sulfurous acid (H2SO3) and dilute H2SO4. For the complete oxidation of the dissolved SO2, an electrolyzer and/or liquid injectants are used. This results in the formation of diluted H2SO4. The diluted H2SO4 is processed in an enrichment unit to produce concentrated H2SO4 and fresh water. A portion of the diluted H2SO4 and/or fresh water is recycled back to the quench tower for the continued acidic absorption of the incoming SO2 in the gas stream, thereby not relying on an external water source.

Claims20

Dependent claims

A method for removing sulfur dioxide (SO2) from a gas stream, the method comprising:

receiving a gas stream comprising CO2, SO2, water vapor, an excess of O2, and traces of SO3 in a quench tower;
contacting, in a lower section of the quench tower, the gas stream with a dilute sulfuric acid (H2SO4) aqueous solution, thereby:
forming a condensed water vapor;
and
dissolving SO2 in the dilute H2SO4 aqueous solution or in the condensed water vapor to form a dissolved SO2 aqueous solution;
partially reacting the dissolved SO2 aqueous solution with the excess of O2 from the gas stream to form a partially oxidized stream comprising sulfurous acid (H2SO3), dilute H2SO4, and unoxidized dissolved SO2;
oxidizing completely, from the partially oxidized stream, the unoxidized dissolved SO2 and H2SO3 in an electrolyzer, or oxidizing the unoxidized dissolved SO2 and H2SO3 by adding a liquid oxidant, to form a dilute H2SO4 acid stream, thereby resulting in the removal of SO2;
cooling the dilute H2SO4 acid stream and splitting the cooled dilute H2SO4 acid stream into two portions;
flowing a first portion of the cooled dilute H2SO4 acid stream to a section above the lower section of the quench tower to contact an incoming gas stream;
and
flowing a second portion of the cooled dilute H2SO4 acid stream to an enrichment unit.

8 more elements

A system for removing sulfur dioxide (SO2) from a gas stream, the system comprising:

a thermal oxidizer comprising a combustion chamber, wherein the thermal oxidizer is configured to receive a gas stream and wherein the combustion chamber is configured to combust the gas stream;
a waste heat recovery system coupled to the thermal oxidizer, wherein the waste heat recovery system is configured to cool an effluent stream from the thermal oxidizer;
a quench tower comprising a lower section, a mid-section, and an upper section, wherein the quench tower is configured to receive a cooled effluent stream from the waste heat recovery system;
an electrolyzer placed downstream of the quench tower, configured to produce a hydrogen (H2) stream and a H2SO4 acid stream;
a cooling system placed downstream of the electrolyzer, configured to cool the H2SO4 acid stream;
a buffer tank configured to receive a cooled H2SO4 acid stream;
a first flowline coupled to the buffer tank, wherein the first flowline is configured to flow a first portion of the cooled H2SO4 acid stream from the buffer tank to the quench tower;
an enrichment unit placed downstream of the buffer tank, wherein the enrichment unit is configured to receive a second portion of the cooled H2SO4 acid stream from the buffer tank to produce a permeate stream and a retentate stream;
and
a collection tank placed downstream of the enrichment unit, configured to receive the permeate stream from the enrichment unit.

7 more elements

Dependencies are inferred from the claim text.