US-12616929-B2 - System for offshore carbon dioxide capture

US12616929B2US 12616929 B2US12616929 B2US 12616929B2US-12616929-B2

Abstract

A capture system for offshore carbon dioxide capture and a method for offshore carbon dioxide capture are described. A capture system for offshore carbon dioxide capture, the system comprising: a pressurised flue gas source configured to provide a pressurised flue gas 101 ; a solvent source configured to provide a liquid solvent; and a two-phase atomising nozzle in fluid communication with the pressurised flue gas source and the solvent source; wherein the two-phase atomising nozzle is configured for two-phase flow of a mixture of the pressurised flue gas and the liquid solvent in order to generate an atomised solvent spray of the liquid solvent.

Inventors

Aslak Einbu
Torbjørn Pettersen
John Morud

Assignees

EQUINOR ENERGY AS

Dates

Publication Date: 20260505
Application Date: 20210329
Priority Date: 20200330

Claims (14)

1 . A carbon dioxide capture system, the system comprising: a pressurized gas source configured to provide a pressurized gas, wherein the pressurized gas is ambient air pressurized by a compressor, fan, blower or pump; a solvent source configured to provide a liquid solvent, wherein the liquid solvent is a substance comprising an amime group; a two-phase atomizing nozzle in fluid communication with the pressurized gas source and the solvent source; wherein the two-phase atomizing nozzle is configured for two-phase flow of a mixture of the pressurized gas and the liquid solvent in order to generate an atomized solvent spray of the liquid solvent; an inlet to the capture system, the inlet being upstream of the two-phase atomizing nozzle and in fluid communication with the pressurized gas source; and an outlet from the capture system, which is downstream of the two-phase atomizing nozzle, so that a part of the pressurized gas enters the inlet and flows past the two-phase atomizing nozzle, being exposed to the atomized solvent spray, before passing out the outlet; wherein the atomized solvent spray is configured to capture carbon dioxide present in the pressurized gas.
2 . The capture system as claimed in claim 1 , wherein the pressurized gas is configured to drive the solvent through the two-phase atomizing nozzle to generate the atomized solvent spray.
3 . The capture system as claimed in claim 1 , wherein the atomized solvent spray, upon generation, comprises solvent droplets having a droplet diameter of 150 μm or less.
4 . The capture system as claimed in claim 1 , further comprising a solvent regeneration unit, wherein the solvent regeneration unit is configured to separate solvent from any carbon dioxide present in the solvent.
5 . The capture system as claimed in claim 4 , wherein the solvent regeneration unit is the solvent source.
6 . The capture system as claimed in claim 1 , further comprising a direct contact cooler downstream of the atomized solvent spray, wherein the direct contact cooler is configured to condense the atomized solvent spray.
7 . The capture system as claimed in claim 1 , further comprising one or more demisters configured to condense the atomized solvent spray.
8 . The capture system as claimed in claim 1 , which is onshore.
9 . A method for carbon dioxide capture, the method comprising: providing a pressurized gas; providing a first part of the pressurized gas to a two-phase atomizing nozzle; providing liquid solvent to the two-phase atomizing nozzle; generating an atomized solvent spray using the two-phase atomizing nozzle; and providing a second part of the pressurized gas to an inlet of a carbon dioxide capture system, the inlet being upstream of the two-phase atomizing nozzle so that said second part of the pressurized gas is exposed to said atomized solvent spray, before passing out an outlet of the capture system, which is downstream of the two-phase atomizing nozzle; wherein the liquid solvent is a substance comprising an amine group; wherein the pressurized gas is ambient air pressurized by a compressor, fan, blower or pump; and wherein the two-phase atomizing nozzle is configured for two-phase flow of a mixture of the pressurized gas and the liquid solvent in order to generate the atomized solvent spray of the liquid solvent.
10 . The method as claimed in claim 9 , comprising: providing the ambient air to the inlet of the carbon dioxide capture system.
11 . The method as claimed in claim 9 further comprising: driving the liquid solvent through the two-phase atomizing nozzle using the pressurized gas.
12 . The method as claimed in claim 9 , comprising: separating solvent from any carbon dioxide present in the solvent using a solvent regeneration unit.
13 . The method as claimed in claim 9 , wherein the method is performed by the capture system of claim 1 .
14 . The method as claimed in claim 9 which is carried out onshore.

Description

The present application claims priority from and is a U.S. National Phase of International Application No. PCT/NO2021/050088, which was filed on Mar. 29, 2021, designating the United States of America and claiming priority to United Kingdom Patent Application No. 2004609.0, filed on Mar. 30, 2020. This application claims priority to and the benefit of the above-identified applications, which are all fully incorporated by reference herein in their entireties. The present invention relates to a capture system for offshore carbon dioxide capture and a method for offshore carbon dioxide capture. The environmental impact caused by carbon dioxide emissions is well documented and well understood to be a significant challenge to overcome. For example, one area of technology where carbon dioxide emission is significant is the international shipping industry. The Third International Maritime Organisation Greenhouse Gas Study (2014) estimated that international shipping emitted carbon dioxide emissions accounting for 2.2% of all manmade emissions, and predicts that without intervention the amount of carbon dioxide emitted by the shipping industry could increase from between 50% and 250% of its current output, due to the general growth of the international shipping industry. In other examples, onshore and offshore oil and gas drilling platforms, vessels and/or refineries may also produce large volumes of CO2 emissions. Similarly, stationary installations including waste combustion plants, power stations and manufacturing plants may all directly contribute to global carbon dioxide emissions. Accordingly, it is desired to provide a solution which significantly reduces carbon dioxide emissions of such systems, including but not limited to ships and other maritime vessels which emit carbon dioxide. Present solutions known in the state of the art use solvents to capture and/or absorb carbon dioxide. One family of solvents which are used for carbon dioxide capture are amines, which generally operate off the following reaction: RNH2+CO2 RNH3++CO- where R represents any suitable hydrocarbon chain compound. Whilst generally referred to as a solvent in the context of gas scrubbing, the solvent does not necessarily dissolve carbon dioxide gas (which may be referred to as a solute in the present context). As will readily be appreciated by the skilled person, the solvent generally bonds with the solute in a reversible reaction. During absorption/capture, the equilibrium is positioned such that the amount of solute captured is maximised. Carbon dioxide capture systems known in the state of the art and used for ships or the like may use a conventional scrubber column, which may comprise tightly packed particulate solvent, placed in the flow path of an exhaust gas or other flue gas to be treated. The column packing of the conventional scrubber column provides an increased surface area to absorb and/or capture the target gas. However, conventional scrubber columns are generally heavy given their solid state. Further, the flue gas must be of a significantly high pressure such that it may be driven through the conventional scrubber column as a result of the pressure differential across the packed absorber. This may require the use of additional pumps and/or compressors, which increase the weight and footprint of the conventional capture system and the energy demands of said system. The conventional scrubber column may also have a relatively high liquid holdup time (i.e. the time which it takes the liquid solvent to pass through the conventional scrubber column) in attempting to maximise the contact time between the surface area of the conventional scrubber column and the solvent. However, the longer a liquid is held up within the conventional scrubber column the heavier the conventional scrubber column effectively is, due to the added weight of the liquid required and residing in the system. As such there is a need to provide an improved, lower weight, compact and more energy efficient carbon dioxide capture system. Viewed from a first aspect the invention provides a capture system for offshore carbon dioxide capture, the system comprising: a pressurised flue gas source configured to provide a pressurised flue gas; a solvent source configured to provide a liquid solvent; and a two-phase atomising nozzle in fluid communication with the pressurised flue gas source and the solvent source; wherein the two-phase atomising nozzle is configured for two-phase flow of a mixture of the pressurised flue gas and the liquid solvent in order to generate an atomised solvent spray of the liquid solvent. It is well understood that increasing a solvent-gas contact area between a solvent and a solute may increase the ability of the solvent to dissolve and/or absorb a solute or other target compound. The provision of a two-phase atomising nozzle negates the need to place a conventional scrubber column in the capture system, as the generated atomised so