Apparatus and method for transporting liquefied carbon dioxide

Abstract

The invention relates to an apparatus and a method for transporting liquefied carbon dioxide, for example, a boat, comprising at least one storage tank (3) configured for storing the liquefied carbon dioxide, a combustion engine (4) configured for propelling the transport apparatus (1), a refrigerator (7) configured for producing cooling power used to cool and liquefy the vaporization gas, further comprising a system (6, 12, 13) for recovering the combustion gases from the engine (4), the combustion gas recovery system (6, 12, 13) comprising a device (6) for capturing carbon dioxide from the combustion gas and a recovery circuit (12, 13) configured to cool and liquefy the captured carbon dioxide via heat exchange with the refrigerator (7) and to return the captured and liquefied carbon dioxide to the tank (3) or to a separate storage location of the apparatus (1). Abstract figure: Fig. 1

Description

Title of the invention: Apparatus and method for transporting liquefied carbon dioxide

[0001] The invention relates to an apparatus and a method for transporting liquefied carbon dioxide, for example a boat.

[0002] The invention relates more particularly to a liquefied carbon dioxide transport apparatus, for example a boat, comprising at least one storage tank configured to store the liquefied carbon dioxide, a combustion engine configured to provide propulsion for the transport apparatus, a refrigerator configured to produce a cold power used to cool and liquefy the vaporization gas.

[0003] To limit greenhouse gas emissions, carbon dioxide (CO2) capture, transport, and storage is one solution. To avoid releasing molecules during transport, ships are generally equipped with a system for liquefying evaporated CO2 through thermal inlets (a refrigerator similar to that used for transporting natural gas).

[0004] Transport vessels whose engine(s) are combustion engines generate exhaust gases rich in CO2 which pose a problem.

[0005] One object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.

[0006] To this end, the apparatus according to the invention, which otherwise conforms to the generic definition given in the preamble above, is essentially characterized in that it further comprises a combustion gas recovery system for the engine, the combustion gas recovery system comprising a device (6) for capturing carbon dioxide from the combustion gas and a recovery circuit configured to cool and liquefy the captured carbon dioxide via a heat exchange with the refrigerator and to return the captured and liquefied carbon dioxide to the tank or to a separate storage of the apparatus.

[0007] Furthermore, embodiments of the invention may include one or more of the following features: - the captured carbon dioxide is subcooled during its liquefaction by heat exchange with the refrigerator, meaning that the carbon dioxide is cooled to a temperature below its saturation temperature, - the vaporization gas is cooled and liquefied by mixing, in a portion of the gas and liquid mixture of the apparatus, with captured liquefied and subcooled carbon dioxide, - the gas and liquid mixture portion is located in the tank and is configured to ensure mixing between the captured, liquefied and subcooled carbon dioxide and the vaporization gas to be liquefied in the tank by spraying, in the upper part of the tank, the cooled, liquefied and subcooled vaporization gas, - The device includes a recovery circuit configured to recover, outside the tank, vaporization gas generated within the tank. - the apparatus includes a recovered vaporization gas cooling section and a return line configured to return the cooled and liquefied vaporization gas to the tank, the cooling section including the portion of gas and liquid mixture that is located outside the tank and configured to ensure mixing between the captured liquefied and subcooled carbon dioxide and the vaporization gas before its return to the tank or separate storage of the apparatus, - the apparatus includes a portion of gas mixture configured to ensure mixing, outside the tank, between the gaseous carbon dioxide captured before its liquefaction and the vaporization gas recovered by the recovery circuit, said gas mixture being cooled and liquefied and preferably subcooled in a heat exchange section with the refrigerator before being returned to the tank or to separate storage of the apparatus.

[0008] The invention also relates to a method for transporting liquefied carbon dioxide using an apparatus conforming to any one of the characteristics above or below, the method comprising a combustion gas recovery step, a carbon dioxide capture step from the combustion gas, and a cooling and liquefaction step for the captured carbon dioxide, the method further comprising a cooling and liquefaction step for vaporization gases generated in the tank, wherein the cooling and liquefaction steps for the captured carbon dioxide and the cooling and liquefaction steps for the vaporization gases utilize the cooling power produced by the same

[0009] The invention may also relate to any alternative device or method comprising any combination of the above or below features within the scope of the claims.

[0010] Other features and advantages will become apparent from the following description, made with reference to the figures in which: Brief description of the figures

[0011] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0012] [Fig. 1] is a schematic and partial view illustrating an example of the structure and operation of a transport device of the invention. Detailed description

[0013] In all figures, the same references refer to the same elements.

[0014] In this detailed description, the following are examples. The fact that the description refers to one or more embodiments does not mean that the features apply only to a single embodiment. Simple features from different embodiments can also be combined and / or interchanged to provide other embodiments.

[0015] The liquefied carbon dioxide transport apparatus 1 illustrated in [Fig. 1] is a boat that carries at least one storage tank 3 configured to store liquefied carbon dioxide. This boat has at least one combustion engine 4 (hydrocarbon mixture) configured to provide propulsion by emitting fumes (combustion gases).

[0016] The engine, in addition to propulsion, can also power one or more refrigerator machines by generating energy for the needs on board the boat. The engine can be, for example, one of the following types: internal combustion engine, total or partial oxy-combustion engine, "SMR" or "ATR" methane reformer, solid oxide fuel cell ("SOFC") or any other technology.

[0017] The transport apparatus 1 also includes a refrigerator 7 configured to produce cooling power used to cool and liquefy the vaporization gas. For example, the refrigerator is configured to liquefy the gas and then subcool the resulting liquid (i.e., liquefied to a temperature below its liquefaction or CO2 saturation temperature).

[0018] For example, the refrigerator 7 is of the cycle circuit type using a cycle fluid that is subjected to a thermodynamic cycle (compression, cooling, then expansion) to produce cooling power, which is transferred to the vaporization gas to cool and liquefy it. This cooling power is transferred, for example, by carrying out a heat exchange between the cooled cycle fluid and the fluid to be cooled (in at least one heat exchanger).

[0019] This refrigerator may be, for example, of the "Turbo Brayton" type marketed by the applicant.

[0020] Other sources of cooling can be considered, such as, for example, an industrial-type mechanical refrigeration unit or a Brayton cycle refrigerator. and particularly a turbobrayton, a heat exchanger configured for cold recovery when liquefied natural gas (LNG) powers the engine, or a heat exchange with a liquid nitrogen storage for example.

[0021] The transport apparatus 1 further comprises a combustion gas recovery system for the engine 4. This combustion gas recovery system includes a device 6 for capturing carbon dioxide from the combustion gas. For example, this capture system may include recovery following amine scrubbing, recovery by oxy-combustion, or cryogenic recovery (e.g., the "Cryocap" process used by the applicant).

[0022] The recovery system further includes a recovery circuit 12, 13 configured to cool and liquefy the captured carbon dioxide via heat exchange with the refrigerator 7 and to return the captured and liquefied carbon dioxide to the tank 3 (or to a separate storage area of ​​the apparatus 1). The apparatus may advantageously include a carbon dioxide purification module. This module may be placed, for example, upstream, in, or downstream of the liquefaction system (refrigerator 7).

[0023] According to an advantageous feature, the vaporization gas can be cooled and liquefied by mixing, in a portion of the gas-liquid mixture of the apparatus 1, with liquefied and subcooled captured carbon dioxide.

[0024] In the illustrated example, the transport apparatus 1 includes a recovery circuit 9 configured to recover vaporization gas generated in tank 3 from outside the tank. Furthermore, the transport apparatus 1 includes a cooling section for the recovered vaporization gas and a return line 10 configured to return the cooled and liquefied vaporization gas to tank 3. This cooling section comprises, or consists of, the portion of the gas-liquid mixture located outside the tank 3 and configured to ensure mixing between the captured and liquefied carbon dioxide and the vaporization gas before its return to tank 3 or separate storage. That is, the vaporization gas is cooled and liquefied by mixing it with the captured, liquefied, and subcooled carbon dioxide. The vaporization gases can thus be condensed by direct mixing with this produced liquid.

[0025] Preferably, the device 1 can be configured to regulate the degree of subcooling of the liquid carbon dioxide from the flue gases to just compensate for the thermal inputs of the tank(s) 3.

[0026] Alternatively or in combination, the portion of the gas-liquid mixture can be located in the tank 3. That is to say, the transport apparatus 1 can be configured to ensure mixing between the captured and liquefied carbon dioxide and the vaporization gas to be liquefied directly in the tank 3, for example by spraying the vaporization gas cooled and liquefied in the upper part of tank 3 (via one or more spray nozzles for example).

[0027] In yet another possible solution (as an alternative or in combination), at least a portion of the captured carbon dioxide could be mixed with the vaporization gas before liquefaction. To this end, the transport apparatus 1 may include a gas-mixing portion configured to ensure mixing, outside the tank 3, between the gaseous carbon dioxide captured before its liquefaction and the vaporization gas recovered by the recovery circuit 9. This gas mixture can then be cooled and liquefied in a heat exchange section with the refrigerator 7 before being returned to the tank 3 or to a separate storage area from the apparatus 1.

[0028] The gas liquefied by the refrigerator 7 can be cooled under saturation conditions or can be cooled to a temperature below its saturation temperature (undercooled).

[0029] As mentioned, the carbon dioxide extracted from the fumes from the propulsion engine(s) can, if necessary, be stored in liquid form in a dedicated storage facility (instead of the main transport tank(s) 3).

Claims

Demands

1. Liquefied carbon dioxide transport apparatus, for example boat, comprising at least one storage tank (3) configured to store the liquefied carbon dioxide, a combustion engine (4) configured to provide propulsion for the transport apparatus (1), a refrigerator (7) configured to produce cooling power used to cool and liquefy the vaporization gas, characterized in that it further comprises a combustion gas recovery system (6, 12, 13) for the engine (4), the combustion gas recovery system (6, 12, 13) comprising a carbon dioxide capture device from the combustion gas and a recovery circuit (12, 13) configured to cool and liquefy the captured carbon dioxide via heat exchange with the refrigerator (7) and to return the captured and liquefied carbon dioxide to the tank (3) or to a separate storage of the apparatus (1).

2. Apparatus according to claim 2, characterized in that the captured carbon dioxide is subcooled during its liquefaction by heat exchange with the refrigerator (7) i.e. that the carbon dioxide is cooled to a temperature below its saturation temperature.

3. Apparatus according to claim 2, characterized in that the vaporization gas is cooled and liquefied by mixing, in a portion of the gas and liquid mixture of the apparatus (1), with liquefied and subcooled captured carbon dioxide.

4. Apparatus according to claim 3, characterized in that the portion of gas and liquid mixture is located in the tank (3) and is configured to ensure mixing between the captured, liquefied and subcooled carbon dioxide and the vaporization gas to be liquefied in the tank (3) by spraying, in the upper part of the tank (3), the cooled, liquefied and subcooled vaporization gas.

5. Apparatus according to claim 1, characterized in that it comprises a recovery circuit (9) configured to recover, outside the tank (3), vaporization gas generated in the tank (3).

6. Apparatus according to claims 2 and 5, characterized in that it comprises a section for cooling the recovered vaporization gas and a return line (10) configured to return in the tank (3) the cooled and liquefied vaporization gas, the cooling section comprising the portion of gas and liquid mixture which is located outside the tank (3) and configured to ensure mixing between the captured liquefied and subcooled carbon dioxide and the vaporization gas before it is returned to the tank (3) or separate storage of the apparatus (1).

7. Apparatus according to claim 4, characterized in that it comprises a portion of gas mixture configured to ensure mixing, outside the tank (3), between the gaseous carbon dioxide captured prior to its liquefaction and the vaporization gas recovered by the recovery circuit (9), said gas mixture being cooled and liquefied and preferably subcooled in a heat exchange section with the refrigerator (7) before being returned to the tank (3) or to separate storage of the apparatus.

8. A method for transporting liquefied carbon dioxide using an apparatus according to any one of the preceding claims, the method comprising a step of recovering the combustion gases, a step of capturing carbon dioxide from the combustion gas and a step of cooling and liquefying the captured carbon dioxide, the method further comprising a step of cooling and liquefying vaporization gas generated in the tank, wherein the steps of cooling and liquefying the captured carbon dioxide and of cooling and liquefying vaporization gas use the cooling power produced by the same refrigerator (7).

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