FR3141967A1 - THERMAL VEHICLE EQUIPPED WITH AN ON-BOARD CO2 CAPTURE AND CONVERSION SYSTEM - Google Patents

Abstract

The vehicle (VTH) is equipped with an on-board system for capturing and converting carbon dioxide (CO2) emitted in the exhaust gases of its thermal engine (MT). According to the invention, the system comprises at least one CO2 storage tank (RC), compact and removable, in which the captured CO2 is stored in the form of supercritical fluid, and a reversible fuel cell (PCR) and a electro-catalytic reactor (REC) which cooperate to produce a synthetic fuel from the captured CO2, the synthetic fuel being supplied to the heat engine to power the combustion. Figure 1

Description

THERMAL VEHICLE EQUIPPED WITH AN ON-BOARD CO2 CAPTURE AND CONVERSION SYSTEM

The present invention relates generally to the reduction in the atmosphere of carbon dioxide (CO2) linked to human activities. More particularly, the invention relates to a thermal vehicle equipped with an on-board system for capturing and converting CO2 emitted in exhaust gases. The invention also relates to a system for capturing and collecting CO2 in a fleet of vehicles rolling with these equipped thermal vehicles.

Several car manufacturers have announced ambitious voluntary commitment targets, ranging from 2035 to 2050, for the carbon neutrality of their operations and their vehicle fleets. Car manufacturers are thus participating in the necessary efforts to limit global warming to a maximum of 2°C by 2100, in accordance with the 2015 Paris Agreement.

Carbon neutrality is a concept that seems simple at first glance, but in reality is very complex to implement, particularly in large industrial organizations with international activities, which is the case in the automotive industry. Carbon neutrality is achieved when the emissions balance is zero, that is, when the CO2 emissions into the atmosphere generated by the company's activities are offset by other activities of the company that remove CO2 from the atmosphere in equal quantities. This concept applies to the entire operation of the company, which covers the entire life cycle of its products, from their manufacture to their recycling, the supplier network, the supply chain, the home-work transport of its employees and many other aspects. Reducing the CO2 emissions of various polluting processes implemented in the company is a first avenue to explore, which is essential from the outset. However, some sectors of activity may face insurmountable obstacles, at least in the short and medium term, taking into account, for example, the state of scientific knowledge and available technology. Companies then have the possibility of resorting to compensatory measures such as participating in reforestation, recycling raw materials, purchasing carbon credits from organizations carrying out concrete actions contributing to the reduction of greenhouse gases, and others.

For car manufacturers, reducing CO2 emissions from the exhaust gases of thermal engines is a priority objective, given the size of the global vehicle fleet, which is expected to peak in 2039 according to forecasts by the Bloomberg New Energy Finance (BNEF) institute. Improvements made to gasoline and diesel thermal engines to improve their efficiency and reduce emissions, as well as the electrification of vehicles, via hybridization and all-electric, are already leading to considerable reductions in CO2 emissions from new-generation vehicles. In addition, improvements made to the engines of new-generation vehicles allow manufacturers to comply, in the short and medium term, with restrictive and evolving regulations on pollutant emissions.

However, although the technical advances made over the last decade towards green, climate-friendly and environmentally friendly mobility are encouraging, the automotive industry still has a long way to go to achieve carbon neutrality.

In the state of the art, devices are known on board thermal vehicles to capture and store the CO2 emitted by the thermal engine. Other devices are also known to convert the CO2 emitted by the thermal engine into a synthetic fuel.

Thus, from document EP2472077A1, a system is known for capturing CO2 in the exhaust gases of a heat engine and storing it in liquid form in a storage tank integrated into a vehicle. The storage tank is designed to be emptied by means of a CO2 recovery installation which is located, for example, in a refueling service station. In addition to the storage tank, the on-board means comprise a purifier tank containing a fluid which absorbs the CO2 present in the exhaust gases. A compressor is also provided for liquefying the CO2 for storage. The capacity of the storage tank is sized sufficiently to obtain a CO2 emptying frequency which is of the same order as the frequency of refueling the vehicle. The driver of the vehicle can thus refuel and empty the CO2 storage tank during the same visit to the refueling service station.

Document US20170306825A1 describes a device for capturing and converting into a synthetic fuel the CO2 emitted by a heat engine. The device comprises a material for capturing gaseous CO2 and a methanization catalyst. In the catalyst, the molecules of CO2 desorbed by the capture material react with molecules of hydrogen H2 to generate methane. The hydrogen is provided by a power source. The capture device controls an increase in the temperature of the capture material, using the heat generated by the heat engine, so as to cause the desorption of the CO2.

Document JP2010235736A describes a system for producing synthetic fuel from captured CO2. A CO2 absorption material allows the capture of the CO2. The thermal energy used to cause the desorption of CO2 is also used to cause the fuel synthesis reaction.

It is desirable to propose a new design of a thermal vehicle equipped with an on-board system for capturing and converting CO2 emitted in exhaust gases, as well as a CO2 capture and collection system adapted to a fleet of these vehicles, in order to help the automobile industry achieve carbon neutrality.

According to a first aspect, the invention relates to a vehicle equipped with a heat engine and an on-board system for capturing and converting carbon dioxide (CO2) emitted in the exhaust gases of the engine. According to the invention, the on-board system comprises at least one compact and removable CO2 storage tank, in which the captured CO2 is stored in the form of supercritical fluid, and a reversible fuel cell and an electro-catalytic reactor which cooperate to produce a synthetic fuel from the captured CO2, the synthetic fuel being supplied to the heat engine to fuel the combustion.

According to a particular characteristic, the on-board system also comprises a device for capturing water present in the exhaust gases of the heat engine, the captured water supplying the reversible fuel cell for the production of hydrogen and oxygen in an electrolyser operating mode thereof, and the hydrogen and oxygen produced being supplied to the electrocatalytic reactor, together with the captured CO2, for the production of the synthetic fuel.

According to another particular feature, excess quantities of the hydrogen and oxygen produced are supplied to the heat engine to fuel the combustion, via an exhaust gas recirculation valve called “EGR” (for “Exhaust Gas Recirculation” in English) thereof.

According to yet another particular feature, an excess quantity of the hydrogen produced is reinjected into the reversible fuel cell for regeneration of its electrodes.

According to yet another particular feature, an excess amount of the produced hydrogen is supplied to the reversible fuel cell for electricity production in a hydrogen fuel cell operating mode thereof.

According to yet another particular characteristic, the electro-catalytic reactor is a Sabatier reactor producing methane gas, as a synthetic fuel, from the captured CO2, and from hydrogen and oxygen produced by the reversible fuel cell.

According to yet another particular feature, methane gas is supplied to the heat engine to fuel the combustion, via a valve called “EGR”.

According to yet another particular feature, the on-board system also includes another storage tank dedicated to storing the synthetic fuel.

According to yet another particular feature, the on-board system also comprises an organic cycle machine, called a "Rankine machine", and a photovoltaic solar panel, the organic cycle machine producing in cogeneration electricity and hot water from the fatal heat of the exhaust gases and the photovoltaic solar panel producing renewable electricity, the electricity produced being used to charge an electrical energy store of the vehicle and the hot water produced being used for heating the vehicle.

The invention also relates to a system for capturing and collecting CO2 in a rolling fleet of vehicles comprising a plurality of vehicles as briefly described above and a collection station comprising means for storing, managing and monitoring the CO2 storage tanks of the vehicles and means for managing user accounts associated with the vehicles.

Other advantages and features of the present invention will become more apparent upon reading the detailed description below of a particular embodiment of the invention, with reference to the single attached drawing, in which:

There is a general block diagram illustrating a particular embodiment of the present invention.

In reference to the , a particular embodiment of a thermal vehicle VTH according to the invention is now described, as well as an exemplary embodiment of an SCC system for capturing and collecting CO2 in a rolling vehicle fleet comprising a plurality of these thermal vehicles VTH.

In general, the thermal vehicle VTH according to the invention comprises an on-board system that captures the gaseous CO2 present in the burnt gases of the thermal engine MT of the vehicle, stores part of the captured CO2 in a compact and removable tank in a supercritical fluid state and converts another part into a synthetic fuel. The synthetic fuel is stored in another tank to be used for combustion in the thermal engine. Products derived from the processes implemented, in the form of excess hydrogen and oxygen, are also used in the combustion of the thermal engine or to produce electricity. An organic Rankine cycle machine, called an “ORC” machine for “Organic Rankine Cycle” in English, can also be integrated into the on-board system for cogeneration of electricity and useful heat, as well as a photovoltaic solar panel, so as to improve the energy balance of the thermal vehicle VTH according to the invention.

As shown schematically in the , the CO2 capture and conversion system on board the VTH thermal vehicle includes in particular a DT CO2 capture and treatment device and a DC CO2 conversion device.

The CO2 capture and treatment device, DT, mainly comprises a CO2 capture device CT, a condensation device CD and a CO2 storage tank RC.

The CT CO2 capture device is bidirectionally connected to a DR exhaust gas bypass device which is installed in the LE exhaust line of the vehicle, downstream of a three-way catalytic converter CAT thereof. The exhaust gases are directed by the DR bypass device to the CT device for CO2 capture by filtration, and then return to the DR bypass device for evacuation via the LE exhaust line. The CT capture device captures CO2 in the burnt gases coming from the combustion chamber of the MT thermal engine, burnt gases which have been depolluted from HC, CO and Nox by the CAT catalyst, in accordance with the emissions standards in force. The CT capture device is formed of a CO2 filter, or CO2 trap, and typically comprises a separation membrane ensuring separation of CO2 and inorganic oxides. This membrane is rigid and is covered with a porous ceramic layer as an external layer. The CT capture device is designed to withstand the high temperature of the exhaust gases, between 300°C and 950°C. Preferably, the shape of the CT capture device is tubular or rectangular, which facilitates its installation in the LE exhaust line.

The function of the CD condensation device is to condense the gaseous CO2 recovered by the CT capture device in the form of a supercritical fluid. The CD condensation device essentially comprises an ET heat exchanger and a PT compressor. The ET heat exchanger and the PT compressor make it possible to bring the CO2 into the required temperature and pressure conditions to obtain the condensation of the CO2 in the supercritical fluid state. The ET heat exchanger is crossed by the gaseous CO2 and is connected to EC circuits for hot water heating and air conditioning of the VTH vehicle. In the ET exchanger, the temperature of the gaseous CO2 is controlled by means of heat exchanges of the gaseous CO2 with the hot water and the air conditioning heat transfer fluid of the EC circuits. The temperature of the gaseous CO2 is thus maintained at a temperature above 31°C which will allow a transition to the supercritical fluid state.

The PT compressor is supplied with electricity by an electrical supply network EL of the VTH vehicle. The PT compressor receives as input the gaseous CO2 conditioned by the ET exchanger at the appropriate temperature, greater than 31 °C, and compresses it to cause its condensation in the supercritical fluid state. At the outlet of the PT compressor, the CO2 in the supercritical fluid state is brought to the RC storage tank to fill it. It will be noted that the function of the PT compressor may in certain embodiments of the invention be provided by the air conditioning compressor of the VTH vehicle operating on a time-share basis.

Condensing CO2 into a supercritical fluid state results in an increase in its density, which allows for the storage of a larger quantity of CO2 in a given volume. The RC storage tank can thus be made in a more compact form. In the present invention, the RC storage tank is a removable tank which, once full, must be removed from the vehicle and replaced by an empty tank. As can be seen in the , the RC storage tank is equipped with a DH filling detector which controls the activation on the dashboard of the vehicle of a full tank indicator for the driver. The capacity of the RC tank, typically between approximately 10 and 20 liters, is a standard capacity which is sized to obtain a tank change frequency which is of the same order as the frequency of refueling the vehicle. The driver of the vehicle can thus fill up with fuel and change his RC tank during the same visit to a refueling service station.

The CO2 conversion device, DC, mainly includes a water capture device CE, a reversible fuel cell PCR, an electro-catalytic reactor REC and a synthesis fuel storage tank RF.

The CE water capture device is a water trap (H2O) that supplies liquid water from the water vapor present in the exhaust gases of the MT thermal engine. The CE water capture device is bidirectionally connected to the DR exhaust gas bypass device. The exhaust gases are directed by the DR bypass device to the CE device for water capture, and then return to the DR bypass device for evacuation via the LE exhaust line.

The PCR reversible fuel cell has two operating modes, namely, a first mode in which it operates as an electrolyzer and a second mode in which it operates as a hydrogen fuel cell.

In the electrolyzer mode, the PCR fuel cell consumes water (H2O) supplied by the CE water trap and electrical energy supplied by the EL power supply network and produces hydrogen (H2) and oxygen (O2). The hydrogen (H2) and oxygen (O2) produced are used by the REC electrocatalytic reactor, together with CO2 from the RC storage tank, to produce synthetic fuel, namely methane (CH4). The excess hydrogen (H2) and oxygen (O2) are supplied to the MT heat engine, via a V_EGR valve of the “EGR” type for “Exhaust Gas Recirculation” in English, to improve the combustion of the MT heat engine and, correlatively, its performance. The excess hydrogen (H2) is also used for the regeneration of the cell, by cleaning its electrodes, as well as for the production of electricity in the hydrogen fuel cell mode.

In the hydrogen fuel cell mode, the PCR cell consumes the above-mentioned excess hydrogen (H2), oxygen (O2) from the air and produces electricity and water (H2O). The electricity produced contributes to the recharging of a high-voltage electrical energy store STK, typically of the Lithuim-ion (Li-ion) type, via electrical conversion means and CH recharge.

The electro-catalytic reactor REC is here of the Sabatier reactor type. The REC reactor consumes hydrogen (H2) and oxygen (O2) produced by the PCR fuel cell in electrolyser mode, as well as CO2 from the RC storage tank and electrical energy supplied by the EL power supply network, and produces methane gas (CH4) as a synthesis fuel. The electricity supplied to the REC reactor is used to heat it to the appropriate temperature for the catalytic reaction, by means of an electrical heating resistor included in the REC reactor. The methane (CH4) produced by the electro-catalytic reactor REC is stored in a synthesis fuel storage tank RF.

The methane (CH4) produced is supplied to the MT thermal engine for combustion, via the aforementioned V_EGR valve. The methane gas (CH4) directed to the V_EGR valve comes directly from the electro-catalytic reactor REC or from the storage tank RF. The V_EGR valve is controlled from measurement information provided by Lambda probes LB1 and LB2 arranged at the inlet and outlet of the engine combustion chamber. The Lambda probe LB1 is typically positioned directly downstream of the V_EGR valve. The Lambda probe LB2 is typically positioned in the gas recirculation loop. The V_EGR valve, controlled by the Lambda probes LB1 and LB2, allows optimal dosing of the recirculation of exhaust gases, as well as hydrogen (H2), oxygen (O2) and methane (CH4) provided by the DC CO2 conversion device, towards the air intake loop AIR of the MT thermal engine.

As also visible at the , the CO2 capture and conversion system also includes an MR organic cycle machine and a PS photovoltaic solar panel.

The organic cycle machine MR is a Rankine machine comprising a heat exchanger EH, called "hot", a heat exchanger EF, called "cold", an electric pump PO and a turbo-alternator TA. The heat exchangers EH, EF, the pump PO and the turbo-alternator TA are integrated in a phase change heat transfer fluid circuit (liquid/gas). The phase changes of the heat transfer fluid are generated by the temperature difference existing between the heat exchangers EH, EF. The heat transfer fluid is heated in the heat exchanger EH crossed by the exhaust gases of the heat engine MT. The heat transfer fluid is cooled in the heat exchanger EF integrated in a hot water heating circuit EC. The work generated in the machine MR is converted into electricity by the turbo-alternator TA, which is rotated by the mechanical torque exerted on its turbine by the heat transfer fluid in gas phase. The electricity produced contributes to recharging the high-voltage electrical energy store STK, via the electrical conversion and recharging means CH. The calories extracted from the heat exchanger EF heat the water in the heating circuit EC, thus contributing to the comfort of the people present in the vehicle VTH.

The PS photovoltaic solar panel is typically arranged on the roof of the vehicle and produces electricity which also contributes to recharging the high-voltage electrical energy store STK, via the electrical conversion and recharging means CH.

The organic cycle machine MR and the photovoltaic solar panel PS contribute to a better recharge of the high-voltage electrical energy store STK, from the fatal heat of exhaust gases and renewable solar energy. An electrical charging socket PG is also provided in the VTH vehicle to supplement the recharge of the high-voltage electrical energy store STK, preferably from an electric charging station providing renewable electrical energy.

The CO2 storage tank, RC, is a removable tank that, when full, must be removed from the VTH vehicle and replaced with an empty tank. In some embodiments, the synthetic fuel storage tank will also be a removable tank replaceable with an empty tank. Advantageously, the RC tank is of a standard interchangeable type. When full, the RC tank has a weight compatible with handling directly by the user for their replacement.

As schematically represented in the , the SCC system according to the invention comprises an SCR station for collecting and replacing full RC tanks. The SCR station comprises means for storing, managing and monitoring the storage tanks and means for managing user accounts associated with said vehicles.

Thus, in this exemplary embodiment, the SCR station is present on the site of an SRC service station for refueling and recharging electric vehicles. The SCR station is in the form of a double automated DRA rack, for self-service storage, which is controlled by a local computerized control and management terminal BGI comprising a MOD management software module with which the user can interact, for example via a dedicated software application on their smartphone or via human-machine interface means (screen, keyboard and others) of the terminal.

VTH vehicles arriving at the SCR station are automatically identified, for example, from a license plate image taken by a CM camera. Once the VTH vehicle has been identified, the BGI terminal calculator interacts with a remote SID computer server hosting DBs of registered users/vehicles and tank management and traceability databases. Tanks are identified individually, for example by a unique QR code. The QR code is scanned for traceability when a full tank is removed and when an empty tank is removed. Validation of a user/vehicle by consulting the remote SID computer server by the BGI terminal leads to a sequential unlocking for the user of two SRP and SRV sections of the automated double rack DRA. The SRP section is used to remove a full RC tank and is unlocked first. Then, once the full tank is removed, the SRV section containing empty RC replacement tanks is unlocked and the user can then remove an empty RC tank and install it in their VTH vehicle.

Users are rewarded for their eco-responsible behavior. Each time a user deposits a full tank of fuel, a credit is credited to their user account, for example, for a discount on a fuel purchase or on the price of an electric recharge of their vehicle.

The filling level of the tank deposited by a user may be controlled and guaranteed by various means. Thus, the removal of the tank from the vehicle may only be authorized when the vehicle's filling detector (DH) indicates a full tank status. In addition, the tank deposited in the SRP deposit section may also be weighed on a scale of the automated double rack before being accepted.

CO2 from reservoirs can be processed by different FT channels shown schematically in . The valorization of CO2 from reservoirs into synthetic fuel can be done on a large scale by synthetic fuel production plants. CO2 can also be used in aquaculture, for example, for the growth of edible algae or microalgae used in the composition of high added value products. CO2, reduced to carbon powder, can also be sequestered in the soil by burial. In addition to the above examples, several other CO2 utilization channels, with or without transformation, are known such as carbon dioxide for carbonated drinks, dry ice, refrigerants, urea in the fertilizer industry, polycarbonates and others.

The invention is not limited to the particular embodiment which has been described here by way of example. Those skilled in the art, depending on the applications of the invention, will be able to make various modifications and variations falling within the scope of protection of the invention.

Claims (10)

Vehicle (VTH) equipped with a heat engine (MT) and an on-board system for capturing and converting carbon dioxide (CO2) emitted in the exhaust gases of said engine (MT), characterized in that said on-board system comprises at least one compact and removable CO2 storage tank (RC), in which the captured CO2 is stored in the form of supercritical fluid, and in that said on-board system also comprises a reversible fuel cell (PCR) and an electro-catalytic reactor (REC) which cooperate to produce a synthetic fuel from the captured CO2, said synthetic fuel being supplied to said heat engine (MT) to fuel the combustion. Vehicle according to claim 1, characterized in that said on-board system also comprises a device (CE) for capturing water present in the exhaust gases of said heat engine (MT), the captured water supplying said reversible fuel cell (PCR) for the production of hydrogen and oxygen in an electrolyser operating mode thereof (PCR), and the hydrogen and oxygen produced being supplied to said electrocatalytic reactor (REC), together with the captured CO2, for the production of said synthetic fuel. Vehicle according to claim 2, characterized in that excess quantities of hydrogen and oxygen produced are supplied to said heat engine (MT) to fuel the combustion, via a valve called “EGR” (V_EGR) thereof. Vehicle according to claim 2 or 3, characterized in that an excess quantity of the hydrogen produced is reinjected into said reversible fuel cell (PCR) for regeneration of the latter's electrodes. Vehicle according to claim 2 or 3, characterized in that an excess quantity of the hydrogen produced is supplied to said reversible fuel cell (PCR) for electricity production in a hydrogen fuel cell operating mode thereof (PCR). Vehicle according to any one of claims 2 to 5, characterized in that said electro-catalytic reactor (REC) is a Sabatier reactor producing methane gas, as said synthetic fuel, from the captured CO2, and from hydrogen and oxygen produced by said reversible fuel cell (PCR). Vehicle according to claim 6, characterized in that said methane gas is supplied to said heat engine (MT) to fuel the combustion, via a valve called “EGR” (V_EGR) thereof. Vehicle according to any one of claims 1 to 7, characterized in that said on-board system also comprises another storage tank (RF) dedicated to storing said synthetic fuel. Vehicle according to any one of claims 1 to 8, characterized in that said on-board system also comprises an organic cycle machine (MR), called a “Rankine machine”, and a photovoltaic solar panel (PS), said organic cycle machine (MR) producing in cogeneration electricity and hot water from the fatal heat of the exhaust gases and said photovoltaic solar panel (PS) producing renewable electricity, the electricity produced being used to charge an electrical energy store (STK) of the vehicle (VTH) and the hot water produced being used for heating (EC) of the vehicle (VTH). System (SCC) for capturing and collecting carbon dioxide (CO2) in a rolling vehicle fleet, characterized in that it comprises a plurality of vehicles (VTH) according to any one of claims 1 to 9 and a collection station (SCR) comprising means (DRA, BGI, SDI, DBs) for storing, managing and monitoring the CO2 storage tanks (RC) of said vehicles (VTH) and means (BGI, SDI, DBs) for managing user accounts associated with said vehicles (VTH).