A system and a method for controlling and monitoring amount of carbon dioxide during handling and / or transport

Abstract

The present invention relates to a system and a method for controlling and monitoring amounts of carbon dioxide during handling and / or transport which system comprises at least one tank used for holding and transporting carbon dioxide. In particular, the present invention relates to a system for controlling and monitoring amount of carbon dioxide during filling and emptying a tank such as a transportable tank which system comprises a tank (1) for carbon dioxide able to withstand a pressure of at least 22 bar, the tank (1) comprises at least one inlet conduit (2, 4) for Carbon dioxide and an outlet conduit (6) for Carbon dioxide, the at least one inlet conduit (2, 4) comprising a valve (3, 5) controlling the amount of carbon dioxide entering the tank (1) through the at least one inlet conduit (2, 4), the outlet conduit (6) comprising an outlet valve (7) controlling the amount of carbon dioxide exiting through the outlet conduit (6), sensors (8, 9) configured to determine the pressure p and the liquid level I inside the tank (1), and connecting means (10) configured to transmit sensor measurements to a controller (11) configured to receive data. Also, the system comprises a sensor (12) configured to measure the temperature T inside the tank (1) and transmit the measurement to the controller (11), and the controller (11) is configured to estimate a value for the content of carbon dioxide inside the tank (1) at time t by determining a value for amount Cliquid of liquid carbon dioxide and a value for amount Cgas of gaseous carbon dioxide.

Description

[0001] The present invention relates to a system and a method for controlling and monitoring amounts of Carbon dioxide during handling and / or transport which system comprises at least one tank used for holding and transporting carbon dioxide.

[0002] In particular, the present invention relates to a system for controlling and monitoring amount of Carbon dioxide during handling and / or transport comprising a tank for holding Carbon dioxide able to withstand a pressure of at least 22 bar which system and method allows for complete account of received and transported Carbon dioxide as well as an estimation of the Carbon dioxide footprint of the transported Carbon dioxide.Background of the invention

[0003] Current methods for transporting Carbon dioxide over land include transport in tank trailers (specifically designed for being hauled by truck) and multipurpose cryogenic ISO tank containers that can be transporter by train, truck or ship. Due the limited market for Carbon dioxide , the current handling of the transported Carbon dioxide relies on manual processes for filling and emptying the tanks, e.g. filling often entails cooling of the tank with nitrogen. With a severely increased volume for Carbon dioxide transport, manual handling will drive costs up and the value of automation will increase.

[0004] The current Carbon dioxide market is based on bilateral commercial agreements between a supplier and a consumer, with limited need for reporting to third parties. Carbon dioxide captured from an emitter needs to be reported to the authorities and it is expected that rigorous monitoring and documentation will be required. In addition, customers (emitters that have captured Carbon dioxide ) are expected to be concerned with the Carbon dioxide footprint related to the transportation and any Carbon dioxide released during handling. Current systems are not focused on this and do not include systems for estimating the Carbon dioxide emissions related to the transport.

[0005] The document EP1457733 A2 relates to a system and method for transferring liquid carbon dioxide from a storage tank (5) pressurised at 300 psi (20,7 bar) to a truck-transportable tank (3) pressurised at about 110 psi (7,6 bar). The system comprises an inlet conduit having a hose portion (7) connected between the storage and transportable tanks (5, 3) for conducting a flow of liquid carbon dioxide therebetween, and a vent hose (39) connected to the transportable tank (3) for venting gaseous carbon dioxide. Pressure regulators (23, 45) are connected to the inlet conduit and vent hoses, respectively. In operation, the first pressure regulator (23) connected to the inlet conduit reduces the pressure of the flow of liquid carbon dioxide entering the transportable tank (3) from 300 psi (20,7 bar) to 175 psi (12 bar), while the second pressure regulator (45) connected to the vent hose (39) maintains a back pressure of 110 psi in the transportable tank while allowing venting of gaseous carbon dioxide. Automatic shut-off and purging mechanisms are provided for shutting off the flow of liquid carbon dioxide when the transportable tank is filled and purging the inlet hose. A muffler (49) is connected to the gas outlet (51) of the vent hose for reducing noise associated with venting of gaseous carbon dioxide. The system allows an operator to automatically fill a transportable cryogenic storage tank with liquid carbon dioxide with a minimum amount of waste and noise. However, the document does not provide a system which makes it possible to control and monitor an amount of carbon dioxide being transported from a filling facility to a storage facility, the document simply provides a system for filling a transportable tank under safe conditions.

[0006] Hence, in order to fulfil present and future demands relating to control and monitoring of how much carbon dioxide is captured, and how much carbon dioxide is lost during filling, moving and emptying of captured carbon dioxide the system and method according to the present invention would be highly advantageous.Summary of the invention

[0007] Thus, an object of the present invention relates to simplifying handling and transport of Carbon dioxide in cryogenic and pressurized tanks by automizing the filling and emptying processes by ensuring transparency and documenting the Carbon dioxide footprint of the handling of the tank by utilizing continuous datalogging and geolocation data.

[0008] Thus, one aspect of the invention relates to a system for controlling and monitoring amount of Carbon dioxide during filling and emptying a tank such as a transportable tank which system comprises: a tank (1) for Carbon dioxide able to withstand a pressure of at least 22 bar, the tank (1) comprises at least one inlet conduit (2, 4) for Carbon dioxide and an outlet conduit (6) for Carbon dioxide, the at least one inlet conduit (2, 4) comprising a valve (3, 5) controlling the amount of Carbon dioxide entering the tank (1) through the at least one inlet conduit (2, 4), the outlet conduit (6) comprising an outlet valve (7) controlling the amount of Carbon dioxide exiting through the outlet conduit (6), sensors (8, 9) configured to determine the pressure p and the liquid level I inside the tank (1), connecting means (10) configured to transmit sensor measurements to a controller (11) configured to receive and store data, wherein the system comprises a sensor (12) configured to measure the temperature T inside the tank (1), and the controller (11) is configured to estimate a value for the content of Carbon dioxide inside the tank (1) at time t by determining a value for amount Cliquid of liquid Carbon dioxide and a value for amount Cgas of gaseous Carbon dioxide.

[0009] Normally, a value for amount C liquid of liquid Carbon dioxide: C liquid (t) = f(V(I),ρ), where the function f depends on the liquid volume V liquid being a function of the liquid level I and the density ρ of the supplied Carbon dioxide, and a value for amount C gas of gaseous Carbon dioxide: C gas (t) = g(p,V(I),T,ρ), where the function g depends on the gas volume V gas being a function of the liquid level I, the pressure p, the temperature T and the density ρ of the supplied Carbon dioxide. However, a skilled person will know how to determine the values based on obtained measurements.

[0010] It is possible to obtain a value for the amount of carbon dioxide inside the tank (1) at any time t, thereby providing a real time monitoring of the Carbon dioxide content.

[0011] According to any embodiment of the first aspect, the tank (1) may comprise a vent line comprising a flow sensor configured to determine flow through the vent line.

[0012] Measuring flow through a vent line may be used to estimate changes in Carbon dioxide content during transport as the content of Carbon dioxide otherwise remains constant as inlet conduit and outlet conduits are closed. Normally, an outlet from the tank 1 to a vent line is positioned at the top of the tank 1.

[0013] According to any embodiment of the first aspect, the system may comprise a positioning sensor (17) such as a GPS (Global Positioning System) determining the geographical location of the tank (1) at time t.

[0014] According to any embodiment of the first aspect, the controller (11) may be configured to control the state of the inlet and outlet valves (3, 5, 6) i.e. whether the valves are open or closed and to what degree each valve is open.

[0015] According to any embodiment of the first aspect, the system may comprise means for cooling of the tank (1). These means may comprise a nozzle for expanding carbon dioxide inside the tank (1).

[0016] The means for cooling may comprise a source of high-pressure gaseous Carbon dioxide, a valve and / or nozzle through which the high-pressure carbon dioxide may enter into the tank (1), a controller configured to initiate cooling upon receiving a signal by opening valve which controller is further configured to receive a signal from a temperature sensor / transmitter, and to compare the signal from the temperature sensor / transmitter to a temperature set point. When the temperature set point is reached, the valve letting high-pressure gaseous carbon dioxide into the tank (1) is closed, and the controller may allow opening a valve (5) for liquid carbon dioxide to further fill the tank (1).

[0017] By applying a cooling system using Carbon dioxide, it is not necessary to have e.g. a traditional nitrogen cooling system.

[0018] According to any embodiment of the first aspect, the tank (1) may comprise an electronic ID such as an RFID, and means for transmitting an ID signal continuously, or at intervals, or upon request. A filling and emptying system may comprise a reader or receiver receiving a transmitted ID signal and transmitting the ID signal to the controller.

[0019] According to any embodiment of the first aspect, the system may comprise or may be connected to a database such as a data collecting system configured to receive data emitted either from the capturing and / or the filling and / or emptying facility to which the tank (1) is connected, or from the tank (1), which database may be configured to transmit data relating to Carbon dioxide-footprint i.e. energy consumed during filling, emptying, transport etc to a calculating unit automatically providing a carbon dioxide footprint.

[0020] According to any embodiment of the first aspect, the system may comprise an indicator for the tank (1) which indicator has at least two states, a first state where the indicator signals that the tank (1) is ready for transport and a second state where the indicator signals that the tank (1) is not ready for transport, the indicator is either configured to provide a visible or audible signal directed to an operator or configured to provide an electronic or digital signal directed to a controller.

[0021] According to any embodiment of the first aspect, the controller (11) may be configured to receive data from a hose-engagement indicator (C1, C2, C3), a sensor (8) indicating tank level (8), and a sensor (17) indicating tank position and depending on the value of each of the received data the indicator is set to either the first state (Ready for transport) or the second state (Not ready for transport).

[0022] According to any embodiment of the first aspect, the system may control and monitor amount of Carbon dioxide during transport, and / or during storage, which system is configured: to receive data from a transport unit (16) or a data receiving system having received data from one or more transport units (16), and / or to receive data from a capture facility (15), and / or to receive data from a geolocation system (17). Brief description of the figures

[0023] Figure 1 shows a schematic figure of a system according to the invention. Figure 2 shows another schematic figure of a system according to the invention. Figure 3 shows a tank according to the invention which may be subjected to automatic filling and emptying.

[0024] The present invention will now be described in more detail in the following.Detailed description of the invention Definitions

[0025] Prior to discussing the present invention in further details, the following terms and conventions will first be defined: In general - when this expression is used when mentioning a feature relating to the present invention, it must be understood that the feature may be used with all embodiments of the invention, even if the mentioning is made in the detailed part of the document.

[0026] The invention relates to a system which can provide a georeferenced mass estimation and continuous monitoring of a tank holding an amount of carbon dioxide no matter whether the tank is transported from one position to another, or the tank is stationary e.g. stored, or the tank is connected to a filling or emptying facility.

[0027] According to the invention, it is possible to automatically prepare a transportable storage tank to receive liquid Carbon dioxide by using Carbon dioxide from an adjacent transportable storage tanks for cooling. to connect a filling facility directly to a tank to be filled with liquid carbon dioxide without the need to use a temporary storage in between. to provide a system comprising communication between a filling facility and a tank being filled, making it possible for the filling facility to prepare a new transportable storage tank, so when filling of one transportable storage tank is almost complete the system can automatically change to fill another tank and thereby ensure a continuously filling operation. to provide a system that calculates and communicates a total carbon footprint for operation and transportation of a tank, including a measurement of carbon dioxide lost to the atmosphere during filling, transport, storage and emptying of the tank.

[0028] Figure 1 illustrates a system according to the invention. The system comprises a controller 11, a data collecting system 13, and a tank 1, the data collecting system 13 may be a cloud-based data system. The system may be connected to or may comprise an external system 14 such as a filling or emptying system, and / or may comprise or connected to a carbon dioxide capture facility 15, also, the system may be connected to a transport unit 16 or at least receive data relating to a transport unit 16. The arrows of fig. 1 illustrate how data are transmitted from the units to the controller 11.

[0029] The tank 1 is configured to hold and to transport Carbon dioxide, this means that the tank 1 normally is able to withstand an internal pressure of at least 22 bars and to be subjected to internal temperatures of at least -30°C.

[0030] Also, the tank 1 is normally configured to be transported i.e. the tank 1 may be configured to be transported by truck, by train, by ship or something else, but normally the tank 1 is not configured to remain stationary at one position.

[0031] When the tank 1 is not empty, the tank 1 may contain Carbon dioxide in two phases, liquid phase and gas phase. A liquid level transmitter or level sensor 8 is connected to the tank 1 and provides a measurement or estimation of the liquid level I of carbon dioxide inside the tank 1. The tank 1 also comprises a pressure transmitter or pressure sensor 9 which is connected to the tank 1 and provides a measurement or estimation of the pressure p inside the tank 1. When level I of liquid Carbon dioxide, the internal pressure p and the internal volume v of the tank 1 are known, it is possible to estimate the mass of Carbon dioxide inside the tank 1 e.g. by using a sounding table for the tank 1. To further improve the measurement or estimation of mass of liquid carbon dioxide inside the tank 1, the density of the Carbon dioxide may be established by analysis, the density of the Carbon dioxide may vary as the Carbon dioxide may contain impurities or contamination with other gases.

[0032] In general, the tank 1 comprises at least one inlet conduit 2, 4 for Carbon dioxide comprising an inlet valve 3, 5, and normally the tank 1 comprises at least two inlet conduits 2, 4 each comprising an inlet valve 3, 5, a first inlet conduit 2 for liquid Carbon dioxide and a second inlet conduit 4 for gaseous Carbon dioxide.

[0033] Also, the tank 1 comprises at least one outlet conduit 6 for Carbon dioxide, the tank 1 may comprise two or more outlet conduits for gaseous and / or liquid Carbon dioxide. Optionally, the tank 1 may comprise a vent line (not shown) which may be connected to the surroundings, and which may e.g. be closed by a release valve, and the release valve may be opened during transport, and / or during filling and / or emptying.

[0034] During filling and emptying the tank 1 is connected to a comprised or to an external system such as a filling and emptying facility 14 via the input / output conduits 2, 4, 6, the filling and emptying facility 14 may be a dedicated filling system or a dedicated emptying system or both. Normally, each input or output conduit 2, 4, 6 connected to the filling and emptying facility 14 comprises a hose engagement indicator C, and each hose engagement indicator C may be ON or OFF or optionally FAIL. If the hose engagement indicator is ON a hose from the external system is joined to the inlet / outlet conduit of the tank 1, and Carbon dioxide may be safely transported between tank and external system. If the hose engagement indicator is OFF, a hose from the external system is not joined or is not secured to the inlet / outlet conduit of the tank, and Carbon dioxide may not be transported between tank and external system. If the hose engagement indicator is FAIL, the state of the hose indicator may be undetermined i.e. neither ON nor OFF and should be controlled by an operator.

[0035] The system also comprises or is connected to a capture facility 15, the capture facility 15 captures and liquefies the Carbon dioxide and may be an industrial unit such as a cement plant, a heating plant or another unit producing significant amounts of Carbon dioxide. The capture facility 15 may provide data relating to energy consumed during liquefication or other processes performed internally in the capturing facility 15 relating to handling of Carbon dioxide. Also, the capture facility 15 may provide information of which kind of energy was used during handling of Carbon dioxide and estimate the carbon footprint of the energy consumption.

[0036] The system may also comprise or be connected to a transport unit 16, the transport unit 16 may be a truck, a train, a ship, or the like, which is used to transport the tank 1 between a capture facility 15 and receiving facility which may be a storage or a use facility. The transport unit 16 or a system adapted to collect data from a several transport units may provide data relating to energy consumption during transport, and the kind of energy consumed during transport which may make it possible to estimate the carbon footprint during transport.

[0037] Either the tank 1 or the transport unit 16 or both may comprise a GPS (Global Positioning System) unit or similar geolocation unit 17 which makes it possible to estimate an exact position of the tank 1 in real time.

[0038] According to the system of the invention, it is possible to obtain a continuous monitoring of handling of Carbon dioxide from the carbon dioxide is captured at a capture facility 15 to a storage or use facility. The continuous monitoring may be used to provide a complete Carbon dioxide footprint by continuously monitoring all states and movements of the Carbon dioxide.

[0039] The continuous monitoring may result in minimized spillage of Carbon dioxide to the atmosphere as spillage is documented and therefore may be understood and prevented, also documentation of handling of the Carbon dioxide including where the Carbon dioxide is transported to and from will be documented.

[0040] The complete carbon footprint is the sum of the carbon footprints from the following individual steps of the Carbon dioxide handling process as each step contribute to the carbon footprint:Capture and liquefaction of Carbon dioxide

[0041] The capture facility 15 i.e., the facility where the Carbon dioxide is produced and / or captured, may estimate a Carbon dioxide footprint for each kg of Carbon dioxide being captured and liquefied at the facility. The Carbon dioxide footprint illustrates the energy used for capturing and liquefying the Carbon dioxide and it is important to know the Carbon dioxide footprint in order to make sure not to spend more energy and potentially release more Carbon dioxide by the capturing and liquefication process than is removed and stored.

[0042] Data related to the Carbon dioxide footprint of capture and liquefaction may be transmitted to a data collecting system 13 receiving data in a database and calculating values for Carbon dioxide footprints. The data collecting system 13 may be a cloud-data system, the data may be transmitted either directly or via other connected equipment such as a filling and / or emptying station. The data relating to Carbon dioxide footprint may be linked to the tank 1 into which the captured and liquefied Carbon dioxide is filled, along with information related to the origin and composition of the Carbon dioxide contributing to the footprint e.g. whether the Carbon dioxide is fossil or based on biological material and information related to the purity of the Carbon dioxide such as density ρ.

[0043] To link to a tank 1, the tank 1 is normally identified by a number or a code, and the tank 1 may therefore comprise an electronic ID such as an RFID, and means for transmitting the ID continuously, or at intervals, or upon request.Filling and / or emptying a tank

[0044] During filling and emptying a tank, energy is used for transferring Carbon dioxide to the tank 1 and for re-liquifying returned Carbon dioxide gas.

[0045] The Carbon dioxide footprint of this process is estimated by the filling / emptying system using information related to the energy supply and flow volumes. If Carbon dioxide is vented to the atmosphere during transport, storing or filling / emptying this may be measured as well. Data collected during the filling / emptying may be transmitted to the data collecting system 13, either directly or via other connected equipment.Cooling or venting during storage

[0046] The tanks may be left for storage prior to or after transportation. A flow indicator configured to measure gas flow in a vent line may indicate if Carbon dioxide is vented during transportation and how much Carbon dioxide is being vented. This data relating to vented carbon dioxide combined with measurements of temperature and pressure is used to estimate loss of Carbon dioxide to atmosphere.

[0047] Also, energy may be used to keep tanks cooled during storage.

[0048] Normally, all data and estimates collected during storage are transmitted to the data collecting system 13 either continuously or at specified time periods.

[0049] Alternatively, values for vented Carbon dioxide may be established by weighing a tank e.g. at the beginning of storage and end of storage, or by weighing the tank at other times or positions during handling and transport.Transportation

[0050] Energy consumption during transport e.g. from a truck or train transporting the Carbon dioxide between a capture facility 15 and a storage facility may be estimated using measurements (e.g. velocity, accelerations, distance, etc) acquired during transport, data acquired from the transporting vehicles data system and / or general vehicle information.

[0051] Data collected from transport vehicles and transmitted to the data collecting system 13, makes it possible to estimate the Carbon dioxide footprint from the complete transport or parts of the transport. Also, the tank 1 may comprise a vibration sensor such as an accelerometer which may contribute to the estimation of travel time or confirm the travel time and possibly also how fast and by which means the tank 1 has been transported.

[0052] Cooling and venting losses may be monitored during transport similar to how it is done during storage. Data and estimates that are collected during transport are transmitted to the data collecting system 13.

[0053] Estimated Carbon dioxide footprints of each phase or period of the transportation is consolidated in the data collecting system 13, where a total Carbon dioxide footprint of the handling of the Carbon dioxide is then estimated by calculation.Transport restriction

[0054] Figure 2 illustrates an embodiment of a system according to the invention which system comprises means ensuring that a tank is not transported from a Carbon dioxide capturing facility to a Carbon dioxide storage facility while being empty, or from a storage facility to a capture facility while being full.

[0055] In general, the system may comprise a transport indicator 18 to be used by an operator or by an automatic controller to determine if a tank is in a preferred state when being moved from A to B. A preferred state may be defined as a combination of a fill level I in the tank 1, the location of the tank 1 and the state of one or more hose engagement indicators.

[0056] The signal of the transport indicator 18 of the shown embodiment is based on data received from sensors 8, 17 where sensor 8 is the liquid level indicator and sensor 17 is a geolocation system providing a position of the tank 1, and indicators C1, C2, C3 combined with defined rules.

[0057] The transport indicator 18 may have at least two states, a first state where the transport indicator 18 transmits a signal that the tank is "ready for transport" and a second state where the transport indicator transmits a signal that the tank is "not ready for transport". The transport indicator 18 may be configured to transmit a visible or audible signal to be received by an operator or an electronic or digital signal to be received by a controller.

[0058] The following is an example of how to establish the value of a transport indicator signal for a tank 1 as illustrated in fig. 3.: 1. If one of the hose engagement indicators C1, C2 or C3 is ON or optionally FAIL, then the transport indicator 18 of the tank 1 signals is NOT ready for transport. 2. If all of the hose engagement indicators C1, C2 or C3 are OFF, then the liquid level I inside the tank 1 and the location of the tank is considered: If tank level > 90% and tank is located within 100m of a capture facility 15, then the transport indicator 18 of the tank signals READY for transport to a storage facility, If tank level < 90% and tank is located within 100m of a capture facility 15, then the transport indicator 18 of the tank signals NOT ready for transport to a storage facility, If tank level < 5% and tank is located within 100m of a Carbon dioxide storage facility, then the tank is READY for transport to a capture facility 15, If tank level > 5% and tank is located within 100m of the Carbon dioxide storage facility, then the container is NOT ready for transport to a capture facility 15.

[0059] The above defined levels and distances are examples for when a tank 1 may be considered either full or empty or close to a storage or capture facility.

[0060] A full level or empty level may depend on the type of tank and on how the tank is transported between capture facility and storage facility. The distance generally defines when a tank is positioned at a facility and may depend on the extent of the facility and how the tank is transported to and from the facility.

[0061] Also, the transport indicator 18 may be configured to rely on rules based on different parameters or data from the tank 1, such as mass of the tank 1, automatic or manual readings of position etc., or data received from the filling / emptying facility such as time of arrival, etc.Automatic filling and emptying system

[0062] When applying a system according to the invention, it is advantageous to apply an automatic filling and emptying system. The tank 1 shown in fig. 3 is configured to be subjected to an automatic filling and / or emptying operation.

[0063] In general, the tank 1 may comprise an identification unit e.g. an electronic ID such as an RFID unit which makes it possible for the filling and emptying system to automatically identify the tank 1, such an identification may make it possible to both establish a filling history for the tank 1 and to identify the type of tank which may be relevant for determining how the tank is connected to the filling / emptying system and on the conditions for the filling / emptying session. The tank 1 and / or the filling and emptying system may comprise means for transmitting or reading the ID continuously, or at intervals, or upon request and to transfer the information to the controller 11.

[0064] The dotted lines illustrate connecting means 10 configured to transmit measurements from sensors 8, 9, 12 to the controller 11, the controller 11 is also configured to receive signals from hose engagement indicators C1, C2, C3 and valves, especially inlet valves 3, 5 and outlet valve 7. The controller 11 is configured to receive the measured and transmitted data from the sensors 8, 9, 12 and provide estimations by calculations and rules, and consequentially open and close valves accordingly to the calculations and rules.

[0065] The connecting means 10 may either be constituted by a system of wires or by a wireless system.

[0066] The system comprises a pressure sensor and transmitter 9 configured to determine the pressure p inside the tank 1, a level sensor and transmitter 8 configured to determine and transmit the level I of liquid carbon dioxide inside the tank, and a temperature sensor and transmitter 12 configured to determine the temperature T inside the tank 1, together these parameters are used to determine the amount of Carbon dioxide inside the tank 1 at any given time t, either upon request or at pre-set intervals or periods.

[0067] The controller 11 is configured to estimate a value for the content of Carbon dioxide inside the tank 1 at time t by determining: a value for amount C liquid of liquid Carbon dioxide: C liquid = f(V(I),ρ), where the function f depends on the liquid volume V liquid being a function of the level I, the temperature T and the density ρ of the supplied Carbon dioxide, a value for amount C gas of gaseous Carbon dioxide: C gas = g(p,V(I),T,ρ), where the function g depends on the gas volume V gas being a function of the level I, the pressure p, the level I, the temperature T and the density ρ of supplied Carbon dioxide .

[0068] The density ρ of the supplied Carbon dioxide may be determined either at the storage facility or at the filling facility and may vary due to impurities in the captured and stored Carbon dioxide .

[0069] Normally, the system comprises a cooling system for cooling the tank 1 before filling, and the cooling system may comprise an expansion system where Carbon dioxide is supplied to the tank 1 at a high pressure and is allowed to expand to a lower pressure inside the tank 1.

[0070] Optionally, a second tank may supply Carbon dioxide used during a cooling procedure. If a second full tank e.g. a previously filled tank 1, is used for the cooling procedure, then the high pressure is around 20 bar and the temperature inside the full tank is around -20°C (253 K). The pressure inside the empty tank to be cooled may be ambient temperature and the pressure may be around 1 bar i.e. around atmospheric pressure. When the full and the empty tanks are connected via an inlet conduit 4 for gaseous Carbon dioxide, the gaseous Carbon dioxide is expanded when entering through nozzles into the empty tank 1, and the empty tank 1 is cooled. When a temperature of around -20 °C is reached, the former empty tank 1 may start filling with liquid Carbon dioxide through a first inlet conduit 2. The liquid Carbon dioxide may be supplied from the storage facility, i.e. from a different unit than the gaseous Carbon dioxide.

[0071] Normally the Carbon dioxide supplied during cooling is supplied via the same manifold as used during filling of a tank 1. Ref. no. Ref. name 1Tank2First inlet conduit3First inlet valve4Second inlet conduit5Second inlet valve6Outlet conduit7Outlet valve8Level sensor9Pressure sensor10Connecting means11Controller12Temperature sensor13Data collecting system14System for filling and emptying15Capture facility16Transport unit17Geolocation system18Transport indicatorC1, C2, C3Hose engagement indicator

Claims

1. A system for controlling and monitoring amount of carbon dioxide during filling and emptying a tank such as a transportable tank which system comprises: - a tank (1) for carbon dioxide able to withstand a pressure of at least 22 bar, the tank (1) comprises at least one inlet conduit (2, 4) for Carbon dioxide and an outlet conduit (6) for Carbon dioxide, - the at least one inlet conduit (2, 4) comprising a valve (3, 5) controlling the amount of carbon dioxide entering the tank (1) through the at least one inlet conduit (2, 4), - the outlet conduit (6) comprising an outlet valve (7) controlling the amount of carbon dioxide exiting through the outlet conduit (6), - sensors (8, 9) configured to determine the pressure p and the liquid level I inside the tank (1), - connecting means (10) configured to transmit sensor measurements to a controller (11) configured to receive data, characterized in that the system comprises a sensor (12) configured to measure the temperature T inside the tank (1) and transmit the measurement to the controller (11), and the controller (11) is configured to estimate a value for the content of carbon dioxide inside the tank (1) at time t by determining a value for amount Cliquid of liquid carbon dioxide and a value for amount Cgas of gaseous carbon dioxide.

2. A system according to claim 1, wherein the tank (1) comprises a vent line comprising a flow sensor configured to determine flow through the vent line.

3. A system according to any previous claim, wherein the system comprises a positioning sensor (17) such as a GPS (Global Positioning System) determining the geographical location of the tank (1) at time t.

4. A system according to any previous claim, wherein the controller (11) is configured to control the state of the valves (3, 5, 6) i.e. whether the valves are open or closed and to what degree each valve is open.

5. A system according to any previous claim, wherein the system comprises means for cooling of the tank (1).

6. A system according to claim 5, wherein the means for cooling comprises a source of high-pressure Carbon dioxide and a nozzle or similar expansion means and a valve controlling the flow of carbon dioxide through the nozzle, the expansion of carbon dioxide into the tank (1) is ended i.e. the valve is closed when a desired low temperature such as a temperature of - 18 °C is reached.

7. A system according to any previous claim, wherein the tank (1) comprises an electronic ID such as an RFID, and means for transmitting the ID continuously, or at intervals, or upon request.

8. A system according to any previous claim, wherein the system comprises or is connected to a database configured to receive data emitted from the capturing and / or filling and / or emptying facility to which the tank (1) is connected, and data emitted from the tank (1), and which database is configured to transmit data relating to Carbon dioxide-footprint i.e. energy consumed during filling, emptying, transport etc.

9. A system according to any previous claim, wherein the system comprises an indicator defining a state for the tank (1) which indicator has at least two states, a first state where the indicator is configured to signal that the tank (1) is ready for transport and a second state where the indicator is configured to signal that the tank (1) is not ready for transport, the indicator is either configured to provide a visible or audible signal directed to an operator or configured to provide an electronic or digital signal directed to a controller.

10. A system according to any previous claim, wherein the controller (11) is configured to receive data from a hose-engagement indicator (C1, C2, C3), tank level (8), and tank position sensor (17) and depending on the value of each of the received data the indicator is set to a first state (Ready for transport) or a second state (Not ready for transport).

11. A system according to any previous claim, wherein the system is configured to control and / or monitor amount of Carbon dioxide during transport, and / or during storage, which system is configured: - to receive data from a transport unit (16) or a data receiving system having received data from one or more transport units (16), and / or - to receive data from a capture facility (15), and / or - to receive data from a geolocation system (17).

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