EP4143565A1

EP4143565A1 - Measurement device for moisture content in supercritical environments

Info

Publication number: EP4143565A1
Application number: EP21722219.9A
Authority: EP
Inventors: Tjerk Jan De Vries
Original assignee: Folium Biosciences Europe BV
Current assignee: Folium Biosciences Europe BV
Priority date: 2020-04-29
Filing date: 2021-04-29
Publication date: 2023-03-08
Also published as: WO2021219816A1

Abstract

The moisture content plays an important role in drying, extraction, impregnation and reaction in liquid and supercritical CO2. Current measuring solutions lack the accuracy, especially over time, to measure the water content. This may negatively impact the quality of the product and/or make the process much less efficient. The invention is a measurement device for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the measurement device comprises: a heater arranged for receiving a sample stream of the mixture, and for heating the sample stream to a set temperature; a pressure reducing element provided downstream of the heater for adiabatic expansion of the sample stream, wherein the expanded sample stream has an expanded pressure and an expanded temperature; a humidity sensor arranged downstream of the pressure reducing element providing a humidity sensor value representing a humidity in the expanded sample stream; and a processor arranged for: receiving the humidity sensor value; adapting the set temperature for heating the sample stream to the adapted set temperature with the heater when the humidity sensor value is outside a humidity range having a minimum humidity value and a maximum humidity value; and calculating the ratio based on the humidity sensor value.

Description

MEASUREMENT DEVICE FOR MOISTURE CONTENT IN SUPERCRITICAL ENVIRONMENTS

FIELD OF THE INVENTION

The invention relates to the field of measurement devices for moisture content in supercritical environments.

BACKGROUND OF THE INVENTION

The moisture content plays an important role in drying, extraction, impregnation and reaction in liquid and supercritical C02. Water can soften material, enhancing extraction and impregnation, and water is in some cases required to allow certain reactions in C02 to take place. In drying applications, detection of the water level is important to monitor the drying process. It is important to accurately measure the moisture content of C02 in these different processes. Current measuring solutions lack the accuracy, especially over time, to measure the water content. This may negatively impact the quality of the product and/or make the process much less efficient.

MORLAND BJORN H ET AL: "Corrosion of Carbon Steel in Dense Phase C02with Water above and Below the Solubility Limit", ENERGY PROCEDIA, ELSEVIER, NL, 1-8 vol. 114, 18 August 2017 (2017-08-18), pages 6752-6765,

XP085178320, ISSN: 1876-6102, DOI: 10.1016/J.EGYPR0.2017.03.1807 ‘section 2., in particular 2.3 * disclose that the water concentration in gases may be measured with a water analyser by reducing the pressure from 95 bar to 2 bar in a venting line. A disadvantage of the disclosed measurement method is that the water concentration may be such that not all the water solved is not dissolved in the gases.

SUMMARY OF THE INVENTION

An object of the invention is to mitigate the disadvantages as mentioned above.

According to a first aspect of the invention, a measurement device for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the measurement device comprises: - a heater arranged for receiving a sample stream of the mixture, and for heating the sample stream to a set temperature;

- a pressure reducing element provided downstream of the heater for adiabatic expansion of the sample stream, wherein the expanded sample stream has an expanded pressure and an expanded temperature;

- a humidity sensor arranged downstream of the pressure reducing element providing a humidity sensor value representing a humidity in the expanded sample stream; and

- a processor arranged for: receiving the humidity sensor value; adapting the set temperature for heating the sample stream to the adapted set temperature with the heater when the humidity sensor value is outside a humidity range having a minimum humidity value and a maximum humidity value; and calculating the ratio based on the humidity sensor value.

The pressure vessel is typically a pressure vessel keeping a particular process under pressure. The amount of the first fluid in the vessel may be in a supercritical state or liquid state. The amount of the first fluid may be an amount of carbon dioxide (C02). The amount of the second liquid may be in a liquid state, in a gas state, or partly in a liquid state and partly in a gas state. The amount of the second fluid may be an amount of water (H20). The amount of the first fluid and the amount of the second fluid is kept as a mixture inside the pressure vessel. The mixture may be accounting for the vessel pressure or may be accounting for a partial pressure of the vessel pressure. Apart from the mixture other materials and/or substances in fluid state may be present in the pressure vessel and may mix with the mixture for together accounting for the vessel pressure.

An opening leading away from the inside of the pressure vessel allows a sample stream to escape from the pressure vessel. The sample stream comprises a sample of the mixture or mix. Via this opening the sample stream is led to a heater.

The heater may heat the sample stream to a set temperature. Depending on other settings, parameters and/or values, the sample stream is heated to a particular temperature, labelled the set temperature. The heater may also be switched off and allow the sample stream to flow through the heater not heated any further. In the latter case the temperature of the sample stream will be the vessel temperature. The vessel temperature is the temperature of the mixture or mix inside the pressure vessel. The pressure reducing element may be a pressure valve releasing the pressure in the sample stream. The pressure reducing element may comprise an opening, such as a nozzle, narrow tube or through hole, leading downstream to a larger compartment for relieving the pressure via an adiabatic expansion of the sample stream. The expanded sample stream has an expanded pressure and an expanded temperature.

The humidity sensor is arranged downstream of the pressure reducing element. The humidity sensor measures a humidity in the expanded sample stream. The humidity sensor provides a humidity sensor value representing the measured humidity. The humidity sensor may measure humidity within a humidity range of 0% to 100%, but typically the humidity sensor has a narrower humidity range where the humidity sensor measures the humidity accurately.

The device further comprises a processor. The processor is arranged such that the processor receives the information for calculating a ratio of an amount of a first fluid and an amount of a second fluid inside the pressure vessel. The calculation of the ratio is based on the humidity sensor value, more specific the humidity. The processor is further arranged for adapting the set temperature of the heater. The set temperature is set to such a value that the expanded sample stream, representing a sample of the mixture inside the pressure vessel, is inside the humidity range. The humidity range is limited for example at 100% as above this value part of the expanded sample stream may solidify and/or liquify.

As the humidity sensor may be used in a very specific or narrow range, the humidity sensor may advantageously be calibrated to a very high accuracy. This has the technical effect that the ratio may be measured with a high accuracy resulting in improved process control inside the pressure vessel. Alternatively, a comparable accuracy as in the prior art may be reached with a relatively simpler humidity sensor as the humidity sensor only has to be suitable to operate at the expanded pressure and not at the vessel pressure.

In an alternative configuration of the processor, the humidity range is shrunk to a single operating point, wherein the set temperature is adapted such that the measured humidity is at or around the single operating point. This provides the advantage that an even simpler and/or even more accurate humidity sensor for this operating point may be used. In an embodiment of the measurement device, calculating the ratio is further advantageously based on a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and/or at the expanded temperature. The saturation vapor pressure at the humidity sensor typically depends on expanded pressure and expanded temperature. Typically, the measurement device advantageously comprises a temperature sensor measuring the expanded temperature, preferably with high accuracy. Typically, the measurement device advantageously comprises a pressure sensor measuring the expanded pressure, preferably with high accuracy. Furthermore typically, the processor advantageously comprises a memory storing a table with saturation vapor pressure values at different temperatures and pressures. Optionally the processor may apply an interpolation to the values on the table to get to a saturation vapor pressure with a higher accuracy at the measured expanded temperature and expanded pressure. Alternatively, the expanded temperature and the expanded pressure may be provided to the measurement device. Alternatively, the saturation vapor pressure value for the current expanded temperature and expanded pressure may be provided to the measurement device.

In an embodiment of the measurement device, calculating the ratio is advantageously based on the formula a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and at the expanded temperature multiplied with the humidity sensor value. The formula is shown below. r = SAT(P_exp,T_exp ) h wherein: r = ratio

SAT = saturated value h = humidity measured by humidity sensor in % of SAT P_exp = expanded pressure T_exp = expanded temperature

The SAT value is typically expressed as a saturated ratio of an amount of a first fluid and an amount of a second fluid. The amount of the first fluid and the amount of the second fluid may be expressed in volume or in weight. The SAT value is typically depending on the external pressure and the external temperature. As an example, when the first fluid is water and the second fluid is C02, the SAT value may be expressed as around 2.5g water / kg C02 at 0°C and ambient pressure. In an embodiment of the measurement device, the processor is arranged for receiving the vessel pressure from a pressure sensor arranged for measuring the pressure of the mixture or the mix in the pressure vessel. The vessel pressure may advantageously add to the control over the process inside the pressure vessel. The vessel pressure may advantageously be monitored to preferably keep the vessel pressure stable to increase the accuracy of the ratio measurement.

In an embodiment of the measurement device, receiving the vessel temperature from a temperature sensor arranged for measuring the temperature of the mixture in the pressure vessel. The vessel temperature may advantageously add to the control over the process inside the pressure vessel. The vessel temperature may advantageously be monitored to preferably keep the vessel temperature stable to increase the accuracy of the ratio measurement.

In an embodiment of the measurement device, the measurement device comprises a memory, wherein the memory is preprogramed with a table defining the saturation vapor pressure value for a plurality of temperatures and/or a plurality of pressures. In an alternative embodiment, the expanded pressure is the ambient pressure or constant pressure. In this embodiment only different saturation vapor pressure values at ambient pressure or constant pressure have to be provided. In an alternative embodiment, the saturation vapor pressure value is calculated based on several sensor values. In an alternative embodiment, the saturation vapor pressure value is provided by an external source. The external source then bases the saturation vapor pressure value on the expanded temperature and expanded pressure.

In an embodiment of the measurement device, the first fluid is carbon dioxide. Carbo dioxide may advantageously be applied in drying applications. Other applications and other first fluids are envisaged by the inventor. In an embodiment of the measurement device, the second fluid is water. Water may advantageously be applied in drying applications. Especially the water level or water content or humidity should be monitored and/or controlled during drying applications. Other applications and other second fluids are envisaged by the inventor.

In an embodiment of the measurement device, the measurement device is arranged for measuring and/or operating with vessel pressures in a range of 20 to 1000 bar, preferably 40 to 500 bar, most preferably 50 to 300 bar. The pressure vessel range is advantageously selected for use in e.g. drying applications, impregnation applications, and/or extraction applications. In an embodiment of the measurement device, the measurement device is arranged for measuring and/or operating with vessel temperatures in a range of -20 to 160 °C, preferably -10 to 140 °C, most preferably 0 to 130 °C. The vessel temperature range is advantageously selected for use in e.g. drying applications, impregnation applications, and/or extraction applications.

In an embodiment of the measurement device, the measurement device is arranged for operating with an expanded pressure below 50 bar, preferably below 20 bar, more preferably below 10 bar, more preferably below 5 bar, even more preferably below 2 bar, most preferably substantially ambient pressure. The expanded pressure may advantageously be selected inside the expanded pressure range for simplifying and/or easing design constraints of the measurement device. The expanded pressure may advantageously be selected at ambient pressure to simplify the measurement device. The expanded pressure may advantageously be selected at ambient pressure to simplify the selection of the saturation vapor pressure value and thus eliminate an additional variable to measure and/or control.

According to another aspect of the invention, a method for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the method comprises:

- receiving a sample stream sampling the mixture in the pressure vessel;

- heating the received sample stream to a set temperature;

- adiabatically expanding the heated sample stream, wherein the expanded sample stream has an expanded pressure and an expanded temperature;

- measuring a humidity value of the expanded sample stream represented as a humidity sensor value;

- adapting the set temperature for heating the sample stream to the adapted set temperature with the heater when the humidity sensor value and/or the humidity is outside a humidity range having a minimum humidity value and a maximum humidity value; and

- calculating the ratio based on the humidity sensor value. The advantages of this method are described throughout the description, especially also for the measurement device. This method may advantageously further be combined with any other feature of an embodiment described in this description to provide the benefits specified with this other feature.

In an embodiment of the measurement device, calculating the ratio is further based on the set temperature, the vessel pressure, the vessel temperature, the expanded pressure, the expanded temperature, and/or a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and/or at the expanded temperature. The advantages of this method are described throughout the description, especially also for the measurement device. This method may advantageously further be combined with any other feature of an embodiment described in this description to provide the benefits specified with this other feature.

According to another aspect of the invention, a computer implemented method for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the method comprises:

- receiving a humidity sensor value from a humidity sensor, wherein the humidity sensor value represents a humidity in an expanded sample stream having an expanded pressure and an expanded temperature; wherein a pressure reducing element is provided upstream of the humidity sensor for adiabatic expansion of a sample stream; and wherein a heater is arranged upstream of the pressure reducing element for heating the unheated sample stream sampling the mixture in the pressure vessel to a set temperature;

- calculating the ratio based on the humidity sensor value. The advantages of this method are described throughout the description, especially also for the measurement device. This method may advantageously further be combined with any other feature of an embodiment described in this description to provide the benefits specified with this other feature. According to another aspect of the invention, a computer program product comprising a computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform any of the computer implemented methods, especially the preceding computer implemented method. The advantages of this computer program product are described throughout the description, especially also for the measurement device. This computer program product may advantageously further be combined with any other feature of an embodiment described in this description to provide the benefits specified with this other feature.

According to another aspect of the invention, a measurement device for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, and wherein the measurement device comprises:

- a processor arranged for: receiving the humidity sensor value; and calculating the ratio based on the humidity sensor value. In this embodiment, the conditions in the pressure vessel are advantageously maintained such that the there is no need for adapting the set temperature, because the conditions make sure that the expanded sample stream has a humidity within the humidity range.

In an embodiment of the measurement device, the measurement device is advantageously combined with any other feature in the description providing the advantageous effects described for these combinations. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings, in which: Figure 1 schematically shows a system comprising an application, and a measurement device according to the invention;

Figure 2 schematically shows a method according to the invention; and Figure 3 schematically shows an embodiment of a computer program product, computer readable medium and/or non-transitory computer readable storage medium according to the invention.

The figures are purely diagrammatic and not drawn to scale. In the figures, elements which correspond to elements already described may have the same reference numerals. LIST OF REFERENCE NUMERALS

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings, in which:

Figure 1 schematically shows a system comprising an application 10, and a measurement device 100 according to the invention. The application may comprise a pressure vessel 15. The pressure vessel may be an enclosed vessel. The application may be a drying application. The application may alternatively be an application for softening materials, enhancing extraction and impregnation. The application may be involving the use of a fluid, such as water, brought into another material or substance, or extracted from another material or substance. The quality of the application may be influenced or determined, most likely highly determined, by the moisture level content in the application, especially over time. The duration for the application to provide a specified level of impregnation and/or extraction to the product may advantageously be positively influenced by employing the current measurement device for monitoring and/or measuring the ratio in the application. The measurement device provides a means for monitoring the composition of the mixture by measuring the ratio and thus for monitoring the application.

The ratio is between (i) an amount of a first fluid and (ii) an amount of a second fluid. The amount of the first fluid may in the pressure vessel be in a supercritical state or liquid state. The amount of the second fluid may be in the pressure vessel in a liquid state, in a gas state, or partly in a of a liquid state and partly in a gas state. The first fluid and the second fluid form a mixture inside the pressure vessel. The mixture may be part of a mix inside the pressure vessel, wherein the mix comprises additional fluids or substances, specifically traces of additional fluids or substances.

The application may comprise an opening 20 in the pressure vessel. The opening is arranged for allowing a sample stream of the mixture and/or mix escape from the pressure vessel. The measurement device may comprise a heater 110 and a tube 105 leading the sample stream from the opening of the pressure vessel to the heater. The heater is arranged for receiving the sample stream of the mixture. The heater is further arranged for heating the sample stream to a set temperature.

In an alternative embodiment, without the heater, the opening in the pressure vessel allows the sample stream to flow directly towards a pressure reducing element 120. This embodiment requires the conditions inside the pressure vessel to be such that heating is not necessary for the measurement device to function, more specifically for the first fluid and/or the second fluid in the expanded sample stream not to solidify and/or the second fluid in the expanded sample stream not to be completely in a liquid state.

The measurement device comprises a pressure reducing element 120 and may comprise a tube 115 leading the heated sample stream from the heater to the pressure reducing element or in the alternative embodiment described above directly from the pressure vessel to the pressure reducing element. The pressure reducing element may be a pressure reducing valve, or an opening, such as a nozzle with a larger chamber behind the opening or nozzle allowing the sample stream to expand to an expanded pressure. The pressure reducing element may be regulated or controlled. Alternatively, the pressure reducing element may be unregulated or uncontrolled.

The measurement device comprises a relative humidity sensor 130 and may comprise a tube 125 leading the expanded sample stream from the pressure reducing element to the relative humidity sensor. The relative humidity sensor may be a relatively simple sensor, such as a relative humidity sensor as the relative humidity sensor may operate at a reduced pressure compared to the pressure of the pressure vessel. The measurement device may further comprise a tube leading the measured sample stream away from the relative humidity sensor to a vent opening 140.

Figure 2 schematically shows a method 200 according to the invention. The method is for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid. The first fluid and the second fluid form a mixture. The mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature.

In figure 2, the method starts with receiving 210 a sample stream sampling the mixture in the pressure vessel. The method optionally continuous with heating 215 the received sample stream to a set temperature. The method continuous with adiabatically expanding 220 the heated sample stream, wherein the expanded sample stream has an expanded pressure and an expanded temperature. The method continuous with measuring 225 a humidity value of the expanded sample stream represented as a humidity sensor value. The method optionally continuous with adapting 230 the set temperature when the humidity sensor value and/or the humidity is outside a humidity range having a minimum humidity value and a maximum humidity value. The method continuous with calculating 235 the ratio based on the humidity sensor value. Multiple steps in the method may be performed in parallel, preferably all steps are performed in parallel, more preferably the steps in the method are performed continuously in parallel. The other methods in the claims and specified in the summary may be derived from the preceding method description.

In a first example for the measurement device or the method, a pressure vessel of 5 litre is filled with 3.00g of water as a second fluid and pressurized to 100 bar with C02 as a first fluid at a temperature of 40°C. The heater heats the sample stream to 88°C. The heated sample stream is expanded via a metering valve to ambient pressure as expanded pressure. The expanded sample stream is passed over or through a relative humidity sensor. The relative humidity measured is 38% at 0°C.

At 100% relative humidity at 0°C and ambient pressure, the amount of water would be 2.5g water/kg C02, therefore the ratio or the amount of water in the C02 is 0.95g water/kg C02.

In a second example for the measurement device or the method, a pressure vessel of 5 litre is filled with 0.10g of water as a second fluid and pressurized to 100 bar with C02 as a first fluid at a temperature of 40°C. The heater heats the sample stream to 88°C. The heated sample stream is expanded via a metering valve to ambient pressure as expanded pressure. The expanded sample stream is passed over or through a relative humidity sensor. The relative humidity measured is below 5% at 0°C. As the relative humidity is below 5%, this is typically outside the humidity range or calibrated range of the relative humidity sensor. Thus, an appropriate or accurate ratio cannot be calculated.

In a third example for the measurement device or the method, a pressure vessel of 5 litre is filled with 0.10g of water as a second fluid and pressurized to 100 bar with C02 as a first fluid at a temperature of 40°C. The heater heats the sample stream to 75°C. The heated sample stream is expanded via a metering valve to ambient pressure as expanded pressure. The expanded sample stream is passed over or through a relative humidity sensor. The relative humidity measured is 15% at -29°C. At 100% relative humidity at -29°C and ambient pressure, the amount of water would be 0.22g water/kg C02, therefore the ratio or the amount of water in the C02 is 0.033g water/kg C02.

The conditions of the pressure vessel in combination with the settings of the measurement device should be selected such that the first fluid in the expanded mixture is at least partly dissolved in the second fluid, wherein the first fluid is at least partly, preferably substantially completely, more preferably completely, in a gas state, and the second fluid in the expanded mixture is at least partly, preferably substantially completely, more preferably completely, in the gas state, and preferably the ratio is within a humidity range of the relative humidity sensor. For example, if the first fluid is selected to be water, it should be prevented that ice forms over or around the relative humidity sensor. For example, if the second fluid is selected to be C02, it should be prevented that dry ice forms over or around the relative humidity sensor.

The application may involve the use of materials, such as waxes, fats or the like, which materials do not dissolve or are brought in a gas state during expansion. These materials may form particles and/or fumes potentially disrupting the measurement or even damaging the humidity sensor. Humidity sensors used for this type of applications typically comprise protective means minimizing misreading of the humidity sensor and/or preventing damage from these materials to the humidity sensor. The protective means may comprise a sintered metal candle filter and/or a plastic candle filter.

Alternative relative humidity sensors envisioned by the inventor and within the scope of the current invention are dew-point humidity sensors, chilled mirrors humidity sensors, optical humidity sensors, or resistance based absolute moisture sensors.

The saturation vapour pressure may be predefined available in a memory or storage in the measurement device or method. The saturation vapour pressure may be provided to the measurement device or method. The saturation vapour pressure may be calculated or derived from other parameters available or made available to the system. The saturation vapour pressure may be calculated by interpolating or extrapolating known saturation vapour pressures at preferable slightly different condition, such as expanded temperature and expanded pressure. The measurement device may comprise an expanded temperature sensor and/or expanded pressure sensor for measuring respectively the expanded temperature and/or the expanded pressure.

The mixture may be filling the pressure vessel together with the solid or fluid material of the application. The mixture may be part of a mix filling the pressure vessel together with the solid or fluid material of the application or any other substance, such as traces of other substances. In this last case the mixture provides a partial pressure in the pressure vessel and the mix comprising the mixture provides the pressure in the pressure vessel.

The humidity range may be the calibration range of the relative humidity sensor. The humidity range may have a maximum relative humidity. The humidity range may have a minimum relative humidity. The humidity range may have a maximum relative humidity and a minimum relative humidity.

Figure 3 schematically shows an embodiment of a computer program product 1000, computer readable medium 1010 and/or non-transitory computer readable storage medium according to the invention comprising computer readable code 1020.

It will also be clear that the above description and drawings are included to illustrate some embodiments of the invention, and not to limit the scope of protection. Starting from this disclosure, many more embodiments will be evident to a skilled person without departing from the scope of the invention as set forth in the appended claims. These embodiments are within the scope of protection and the essence of this invention and are obvious combinations of prior art techniques and the disclosure of this patent. Devices functionally forming separate devices may be integrated in a single physical device.

The term “substantially” herein, such as in “substantially all emission” or in “substantially consists”, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of.

The term "functionally" will be understood by, and be clear to, a person skilled in the art. The term “substantially” as well as “functionally” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective functionally may also be removed. When used, for instance in “functionally parallel”, a skilled person will understand that the adjective “functionally” includes the term substantially as explained above. Functionally in particular is to be understood to include a configuration of features that allows these features to function as if the adjective “functionally” was not present. The term “functionally” is intended to cover variations in the feature to which it refers, and which variations are such that in the functional use of the feature, possibly in combination with other features it relates to in the invention, that combination of features is able to operate or function. For instance, if an antenna is functionally coupled or functionally connected to a communication device, received electromagnetic signals that are receives by the antenna can be used by the communication device. The word “functionally” as for instance used in “functionally parallel” is used to cover exactly parallel, but also the embodiments that are covered by the word “substantially” explained above. For instance, “functionally parallel” relates to embodiments that in operation function as if the parts are for instance parallel. This covers embodiments for which it is clear to a skilled person that it operates within its intended field of use as if it were parallel.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements.

The devices or apparatus herein are amongst others described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation or devices in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and “to include”, and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Also, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an." The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device or apparatus claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention further applies to an apparatus or device comprising one or more of the characterising features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterising features described in the description and/or shown in the attached drawings.

It will be appreciated that the invention also applies to computer programs, particularly computer programs on or in a carrier, adapted to put the invention into practice. The program may be in the form of a source code, a code intermediate source and an object code such as in a partially compiled form, or in any other form suitable for use in the implementation of the method according to the invention. It will also be appreciated that such a program may have many different architectural designs. For example, a program code implementing the functionality of the method or system according to the invention may be sub-divided into one or more sub-routines. Many different ways of distributing the functionality among these sub-routines will be apparent to the skilled person. The sub-routines may be stored together in one executable file to form a self-contained program. Such an executable file may comprise computer-executable instructions, for example, processor instructions and/or interpreter instructions (e.g. Java interpreter instructions). Alternatively, one or more or all of the sub-routines may be stored in at least one external library file and linked with a main program either statically or dynamically, e.g. at run-time. The main program contains at least one call to at least one of the sub-routines. The sub-routines may also comprise function calls to each other. An embodiment relating to a computer program product comprises computer-executable instructions corresponding to each processing stage of at least one of the methods set forth herein. These instructions may be sub divided into sub-routines and/or stored in one or more files that may be linked statically or dynamically. Another embodiment relating to a computer program product comprises computer-executable instructions corresponding to each means of at least one of the systems and/or products set forth herein. These instructions may be sub divided into sub-routines and/or stored in one or more files that may be linked statically or dynamically.

The carrier of a computer program may be any entity or device capable of carrying the program. For example, the carrier may include a data storage, such as a ROM, for example, a CD ROM or a semiconductor ROM, or a magnetic recording medium, for example, a hard disk. Furthermore, the carrier may be a transmissible carrier such as an electric or optical signal, which may be conveyed via electric or optical cable or by radio or other means. When the program is embodied in such a signal, the carrier may be constituted by such a cable or other device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted to perform, or used in the performance of, the relevant method.

The various aspects discussed in this patent can be combined in order to provide additional advantages. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

1. Measurement device (100) for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel (15), wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the measurement device comprises:

- a heater (110) arranged for receiving a sample stream of the mixture, and for heating the sample stream to a set temperature;

- a pressure reducing element (120) provided downstream of the heater for adiabatic expansion of the sample stream, wherein the expanded sample stream has an expanded pressure and an expanded temperature;

- a humidity sensor (130) arranged downstream of the pressure reducing element providing a humidity sensor value representing a humidity in the expanded sample stream; and

2. Measurement device according to the preceding claim, wherein calculating the ratio is further based on a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and/or at the expanded temperature, and preferably wherein calculating the ratio is based on the formula a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and at the expanded temperature multiplied with the humidity sensor value.

3. Measurement device according to any of the preceding claims, wherein the processor is arranged for: receiving the vessel pressure from a pressure sensor arranged for measuring the pressure of the mixture in the pressure vessel; and/or receiving the vessel temperature from a temperature sensor arranged for measuring the temperature of the mixture in the pressure vessel.

4. Measurement device according to any of the preceding claims, comprising a memory, wherein the memory is preprogramed with a table defining the saturation vapor pressure value for a plurality of temperatures and/or a plurality of pressures.

5. Measurement device according to any of the preceding claims, wherein the first fluid is carbon dioxide.

6. Measurement device according to any of the preceding claims, wherein the measurement device is arranged for measuring and/or operating with vessel pressures in a range of 20 to 1000 bar, preferably 40 to 500 bar, most preferably 50 to 300 bar; and/or wherein the measurement device is arranged for measuring and/or operating with vessel temperatures in a range of -20 to 160 °C, preferably -10 to 140 °C, most preferably 0 to 130 °C; and/or wherein the measurement device is arranged for operating with an expanded pressure below 50 bar, preferably below 20 bar, more preferably below 10 bar, more preferably below 5 bar, even more preferably below 2 bar, most preferably substantially ambient pressure.

7. Method for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in a pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the method comprises:

- receiving (210) a sample stream sampling the mixture in the pressure vessel;

- heating (215) the received sample stream to a set temperature;

- adiabatically expanding (220) the heated sample stream, wherein the expanded sample stream has an expanded pressure and an expanded temperature;

- measuring (225) a humidity value of the expanded sample stream represented as a humidity sensor value;

- adapting (230) the set temperature for heating the sample stream to the adapted set temperature with the heater when the humidity sensor value is outside a humidity range having a minimum humidity value and a maximum humidity value; and

- calculating (235) the ratio based on the humidity sensor value.

8. Method according to the preceding claim, wherein calculating the ratio is further based on the set temperature, the vessel pressure, the vessel temperature, the expanded pressure, the expanded temperature, and/or a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and/or at the expanded temperature.

9. Computer-implemented method for measuring a ratio of (i) an amount of a first fluid in a supercritical state or liquid state and (ii) an amount of a second fluid in said first fluid, wherein the first fluid and the second fluid form a mixture, wherein the mixture is in an pressure vessel, wherein the pressure vessel has a vessel pressure and a vessel temperature, wherein the second fluid is water, and wherein the method comprises:

- receiving a humidity sensor value from a humidity sensor, wherein the humidity sensor value represents a humidity in an expanded sample stream having an expanded pressure and an expanded temperature; wherein a pressure reducing element is provided upstream of the humidity sensor for adiabatic expansion (220) of a sample stream; and wherein a heater is arranged upstream of the pressure reducing element for heating (215) the unheated sample stream sampling the mixture in the pressure vessel to a set temperature;

- calculating (235) the ratio based on the humidity sensor value.

10. Computer-implemented method according to the preceding claim, wherein calculating the ratio is further based on a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and/or at the expanded temperature.

11. Computer-implemented method according to the preceding claim, wherein calculating the ratio is based on the formula a saturation vapor pressure value of the second fluid in the first fluid at the expanded pressure and at the expanded temperature multiplied with the humidity sensor value.

12. Computer program product (1000) comprising a computer readable medium (1010) having computer readable code (1020) embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform any of the computer implemented methods of claim 9-11.