Method and system for storing organic acids

Abstract

The invention provides a method of storing an organic acid, the method comprising the steps of obtaining a measurement of a parameter of the organic acid; obtaining an environmental parameter; determining an amount of a diluent to combine with the organic acid based on the measurement of the organic acid and the obtained temperature, and combining the diluent with the organic acid.

Description

FIELD OF THE INVENTION The present invention relates to a method and system for storing organic acids. More particularly, but not exclusively, it relates to monitoring a temperature and adding a diluent to a product comprising an organic acid output from a catalytic reaction to provide a mixture having a lower freezing point. BACKGROUND OF THE INVENTION Processes where organic acids, such as formic acid, acetic acid, propionic acid and butyric acid, are produced, require consideration of the handling and / or storage of the organic acids after production. As these organic acids can have relatively high freezing rates, it may be necessary to maintain the organic acids above a set temperature. For example, in the production of acetic acid from ethanol by a partial oxidation catalytic process, it may be necessary for the temperature of the equipment handling and storing the acetic acid product to be maintained above at least 16.6 C. This is difficult in environments where the ambient temperature is either consistently or intermittently at or below this temperature or where environmental conditions are less predictable. In some cases, the temperature of the organic acid can be maintained by a control system or, for example, an insulated container. However, it can be complex or inefficient to maintain the required temperatures over extended periods of time. It is an object of the present invention to provide a system and / or method which overcomes or at least partially ameliorates some of the abovementioned disadvantages or which at least provides the public with a useful choice. BRIEF DESCRIPTION OF THE INVENTION In one aspect the invention broadly comprises a method of storing an organic acid, the method comprising the steps of: (optionally) obtaining a measurement of a parameter of the organic acid; obtaining an environmental parameter; determining an amount of a diluent to combine with the organic acid based on the measurement of the organic acid and the obtained temperature, and combining the diluent with the product. In a further aspect, the invention provides a method of storing a product comprising organic acid output from a catalytic reaction, the method comprising the steps of: obtaining a measurement of a parameter of the product; obtaining an environmental parameter; determining an amount of a diluent to combine with the product, and combining the diluent with the organic acid to provide a mixture, wherein the amount of the diluent is based on the measurement of the product and the obtained environmental parameter to substantially maintain the mixture in a fluid of flowable condition. In a further aspect, the invention provides a method of storing a product comprising an organic acid output from a catalytic reaction, the method comprising the steps of: obtaining a measurement of a parameter of the product; obtaining an environmental parameter; determining an amount of a diluent to combine with the product based on the measurement of the product and the obtained environmental parameter to provide a mixture having a target freezing point; and combining the diluent with the product comprising the organic acid to provide the mixture having the target freezing point. In a further aspect, the invention provides a method of transporting or handling a product comprising an organic acid output from a catalytic reaction, the method comprising the steps of: obtaining a measurement of a parameter of the product; obtaining an environmental parameter; determining an amount of a diluent to combine with the product based on the measurement of the product and the obtained environmental parameter to provide a mixture having a target freezing point; and combining the diluent with the product comprising the organic acid to provide the mixture having the target freezing point. The measurement of a parameter of the product may be a measurement of a parameter of the organic acid. In some examples, the step of obtaining a measurement of a parameter of the product may be optional, such that the method comprises: obtaining an environmental parameter; determining an amount of a diluent to combine with the product based on the obtained environmental parameter, preferably to provide a mixture having a target freezing point; and combining the diluent with the product comprising the organic acid. The freezing point may be a freezing point of an organic acid containing mixture (e.g., organic acid and diluent mixture). The freezing point may be lowered to reduce the risk or potential for freezing of the organic acid (or organic acid containing mixture), or to at least assist in preventing said freezing, such as based on a current or projected temperature. The freezing point may be controlled (e.g., lowered) to maintain the organic acid in a flowable condition, such as liquid and / or vapour phase (i.e., as a fluid), or a phase change intermediary (e.g., a slurry). The freezing point may be lowered to or below a target freezing point. The target freezing point may be determined (e.g., calculated) based on the environmental parameter. The environmental parameter is preferably a temperature. The temperature may be a temperature of a or the storage vessel, an ambient temperature, a forecast temperature, or even a temperature of the organic acid (this may still be considered an environmental parameter). In a further aspect, the invention provides a method of storing a product comprising an organic acid output from a catalytic reaction, the method comprising the steps of: obtaining a measurement of a parameter of the product, such as of the organic acid; obtaining a temperature, such as: a temperature of the product, an ambient temperature, a forecast temperature, a temperature of a storage vessel; determining an amount of a diluent to combine with the product, including determining a target freezing point based on the obtained environmental parameter and selecting an amount of diluent to combine with the product based on the obtained measurement of the parameter of the product to provide a mixture having a target freezing point, and combining the diluent with the organic acid according to the determined amount, such as to provide the target freezing point. For any of the methods described herein: Optionally, the method further comprises producing the organic acid by performing the catalytic reaction. Optionally, the catalytic reaction comprises dehydrogenation. Optionally, the catalytic reaction comprises partial dehydrogenation. Optionally, the catalytic reaction comprises a partial oxidation catalyst. Optionally, the catalytic reaction comprises partial dehydrogenation electrolysis. Optionally, the catalytic reaction comprises a partial oxidation electrolyser. Optionally, the output is from an electrolyser. Optionally, the electrolyser comprises a partial oxidation catalyst. Optionally, the parameter of the product is a parameter of the organic acid. Optionally, the parameter of the product comprises an amount of product or organic acid in a conduit to a storage vessel. Optionally, the parameter of the product comprises an amount of product or organic acid in a or the storage vessel. Optionally, the amount is a volume. Optionally, combining the diluent with the product comprises mixing the diluent and product. Optionally, the mixing uses a mixer, optionally wherein the mixing occurs on entry of the product and / or diluent into the storage vessel. Optionally, combining the diluent with the product is controlled by one or more variable speed pumps and / or valves. Optionally, the parameter of the product comprises a reaction rate of the catalytic reaction, optionally a reaction rate in the electrolyser. Optionally, the parameter comprises a flow rate of at least one output of the catalytic reaction, optionally from the electrolyser. Optionally, the parameter comprises a mass flow rate. Optionally, the output is the organic acid output. Optionally, the parameter of the product comprises a flow rate of an input to catalytic reaction, optionally an input to the electrolyser. Optionally, the at least one output is a hydrogen output. Optionally, obtaining a measurement comprises obtaining a measured value from at least one sensor. Optionally, the at least one sensor comprises a mass-flow sensor. Optionally, the at least one sensor comprises a volume-flow sensor. Optionally, the measurement comprises an estimation. Optionally, the estimation comprises one or more of: a correlation with a feed rate into the catalytic reaction, optionally into the electrolyser, an electrical measurement, for example a current, used in the catalytic reaction, optionally the electrolyser, and a flow rate of hydrogen from the catalytic reaction, optionally from the electrolyser, optionally from the catalyst. Optionally, the parameter of the product comprises a composition of the product, such as the presence or prevalence of one of more contaminants. Optionally, the environmental parameter comprises a temperature. Optionally, the temperature comprises a temperature of the product. Optionally, the temperature comprises a temperature of a or the storage vessel. Optionally, the temperature comprises an ambient temperature. Optionally, the temperature comprises a forecast temperature. Optionally, the method comprises the step of obtaining a weather forecast. Optionally, the diluent comprises an alcohol. Optionally, the alcohol is a hydrogenized alcohol of the organic acid. Optionally, the alcohol is an input for the catalytic reaction, such that the alcohol is used as both a reactant and a diluent. Optionally, determining the amount of diluent comprises determining a percentage of diluent relative to organic acid. Optionally, the diluent is selected for separability from the organic acid. Optionally, combining the diluent with the product comprises introducing diluent from a diluent storage vessel. Optionally, the diluent storage vessel is an alcohol storage vessel also configured to supply the catalytic reaction, optionally the electrolyser. 5              Optionally, the diluent storage vessel is a water storage vessel. Optionally, combining the diluent with the product comprises introducing diluent from an output of a fuel cell. Optionally, an input of the fuel cell is connected to an output of the catalytic reaction, optionally a or the electrolyser. 10              Optionally, the fuel cell comprises a hydrogen fuel cell. Optionally, the parameter of the product comprises an amount of the product or organic acid in a conduit connected to the storage vessel. Optionally, the method further comprises the step of calculating the amount of product or organic acid in the storage vessel based on the measurement in the conduit. 15            Optionally, the parameter of the product comprises an amount of the product or organic acid in a or the storage vessel. Optionally, the parameter of the product comprises one or more of an amount or a concentration of the organic acid. Optionally, the parameter of the product comprises a production rate of organic 20 acid. Optionally, the parameter of the product comprises a flow rate of an input into the catalytic reaction, optionally the electrolyser, or an output from the catalytic reaction, optionally the electrolyser. Optionally, the parameter of the product comprises a current density across the 25 electrolyser and / or a catalyst of the electrolyser. Optionally, the parameter of the product comprises a concentration of the organic acid in the storage vessel. Optionally, the method comprises the step of obtaining the measurement of the parameter of the product at a first location; and combining the diluent and product at a 30 second location, the second location downstream of the first location. Optionally, determining the amount of diluent to combine comprises selecting an amount of diluent to provide a target freezing point. Optionally, determining the amount of diluent to combine comprises selecting an amount of diluent to lower the freezing point of the mixture to or below a target freezing point. Optionally, the target freezing point is dependent on the obtained environmental parameter, preferably temperature. Optionally, determining the amount of diluent to combine comprises determining the target freezing point based on the obtained environmental parameter. Optionally, the target freezing point represents a minimum expected temperature within a time period. Optionally, the time period is preset. Optionally, determining the amount of diluent to combine with the product comprises determining a concentration of diluent in the storage tank and a rate of product flow into the storage tank. Optionally, the step of obtaining a measurement of an outflow from the storage vessel. Optionally, the method comprises the step of obtaining a measurement of the volume of diluent and organic acid within the storage vessel. Optionally the environmental parameter comprises a temperature. Optionally the organic acid is an output from a catalytic reaction. Optionally the catalytic reaction comprises dehydrogenation. Optionally the catalytic reaction comprises partial dehydrogenation. Optionally the catalytic reaction comprises a partial oxidation catalyst. Optionally the catalytic reaction comprises partial dehydrogenation electrolysis. Optionally the catalytic reaction comprises a partial oxidation electrolyser. Optionally the output is from an electrolyser. Optionally the electrolyser comprises a partial oxidation catalyst. Optionally the parameter of the organic acid comprises an amount of organic acid in a conduit to a storage vessel. Optionally the parameter of the organic acid comprises an amount of organic acid in a or the storage vessel. Optionally the amount is a volume. Optionally combing the diluent with the organic acid comprises mixing the diluent and organic acid. Optionally the mixing uses a mixer. Optionally the mixing occurs on entry of the organic acid and / or diluent into the storage vessel. Optionally combining the diluent with the organic acid is controlled by one or more variable speed pumps and / or valves. Optionally the parameter of the organic acid comprises a reaction rate of a reaction in the electrolyser. Optionally the parameter of the organic acid comprises a flow rate of an output from the electrolyser. Optionally the parameter of the organic acid comprises a mass flow rate of an output from the electrolyser. Optionally the output is the organic acid output. Optionally the output is a hydrogen output. Optionally the parameter of the organic acid comprises a flow rate of an input to the electrolyser. Optionally obtaining a measurement comprises obtaining a measured value from at least one sensor. Optionally the at least one sensor comprises a mass-flow sensor. Optionally the at least one sensor comprises a volume-flow sensor. Optionally the measurement comprises an estimation. Optionally the estimation comprises one or more of: a correlation with a feed rate into the electrolyser, an electrical measurement, for example a current, used in the electrolyser, or a flow rate of hydrogen from the electrolyser from the catalyst. Optionally the temperature comprises a temperature of the organic acid. Optionally the temperature comprises a temperature of the storage vessel. Optionally the temperature comprises an ambient temperature. Optionally the temperature comprises a forecast temperature. Optionally the method comprises the step of obtaining a weather forecast. Optionally the diluent comprises an alcohol. Optionally the alcohol is a hydrogenized alcohol of the organic acid. Optionally determining the amount of diluent comprises determining a percentage of diluent relative to organic acid. Optionally the diluent is selected for separability from organic acid. For example, ethanol may be more easily separated from organic acids than water. Optionally combining the diluent with the organic acid comprises introducing diluent from a diluent storage vessel. Optionally the diluent storage vessel is an alcohol storage vessel, wherein the alcohol storage vessel is also configured to supply the electrolyser. Optionally the diluent storage vessel is a water storage vessel. Optionally combining the diluent with the organic acid comprises introducing diluent from an output of a fuel cell. Optionally an input of the fuel cell is connected to an output of a or the electrolyser. Optionally the fuel cell comprises a hydrogen fuel cell. Optionally the parameter of the organic acid comprises an amount of the organic acid in a conduit connected to the storage vessel. Optionally the method comprises the step of calculating the amount of organic acid in the storage vessel based on the measurement in the conduit. Optionally the parameter of the organic acid comprises an amount of the organic acid in the storage vessel. Optionally the parameter of the organic acid comprises one or more of an amount or a concentration of the organic acid. Optionally the parameter of the organic acid comprises a production rate of organic acid. Optionally the parameter of the organic acid comprises a flow rate of an input into the electrolyser or an output from the electrolyser. Optionally the parameter of the organic acid comprises a current density across the electrolyser and / or a catalyst of the electrolyser. Optionally the measurement comprises a concentration of the organic acid in the storage vessel. Optionally the method comprises the step of obtaining the measurement of the parameter of the organic acid at a first location, and combining the diluent and organic acid at a second location, the second location downstream of the first location. Optionally determining the amount of diluent to combine comprises selecting an amount of diluent to provide a target freezing point. Optionally wherein the target freezing point is dependent on the obtained temperature. Optionally wherein the target freezing point represents a minimum expected temperature within a time period. Optionally wherein the time period is preset. Optionally determining the amount of diluent to combine with the organic acid comprises determining a concentration of diluent in the storage tank and a rate of organic acid flow into the storage tank. Optionally the method comprises the step of obtaining a measurement of an outflow from the storage vessel. Optionally the method comprises the step of obtaining a measurement of the volume of diluent and organic acid within the storage vessel. In a further aspect, the invention provides a system for storing a product comprising an organic acid output from a catalytic reaction, the system comprising: a storage vessel configured to store the product; a diluent source configured to provide a diluent to combine with the product; a controller configured to: obtain a measurement of the product; obtain an environmental parameter; determine an amount of the diluent to combine with the product based on the measurement of the product and the obtained environmental parameter to provide a mixture having a target freezing point; and control the diluent from the diluent source into the storage vessel according to the determined amount to provide the mixture having the target freezing point. In a further aspect, the invention provides a controller configured to control the freezing point of a product comprising an organic acid, wherein the organic acid is an output of a catalytic reaction, the controller configured to: obtain a measurement of the product; obtain an environmental parameter; determine an amount of a diluent to combine with the product based on the measurement of the product and the obtained environmental parameter; and control the diluent from the diluent source into the storage vessel according to the determined amount. In a further aspect, the invention provides a system comprising: an electrolyser configured to produce a product comprising an organic acid output via a catalytic reaction, a fuel cell, a product storage tank configured to store the product output from the electrolyser, a diluent storage tank; wherein the diluent storage tank is fluidly connected to the product storage tank to allow the organic acid to be diluted to control the freezing point of the product. In a further aspect, the invention provides a system for storing organic acids comprising: a storage vessel configured to store the organic acid; a diluent source configured to provide a diluent to combine with the organic acid; a controller configured to: obtain a measurement of the organic acid; obtain an environmental parameter; determine an amount of the diluent to combine with the organic acid based on the measurement of the organic acid and the obtained temperature; and control the diluent from the diluent source into the storage vessel according to the determined amount. In a further aspect, the invention provides a controller configured to control the freezing point of an organic acid in a storage vessel, the controller configured to: obtain a measurement of the organic acid; obtain an environmental parameter; determine an amount of a diluent to combine with the organic acid based on the measurement of the organic acid and the obtained temperature; and control the diluent from the diluent source into the storage vessel according to the determined amount. In a further aspect, the invention provides a system comprising: an electrolyser, a fuel cell, an alcohol storage tank, a diluent storage tank wherein the diluent storage tank is fluidly connected to the acid storage tank to allow the acid to be diluted. Optionally the systems and / or controllers are configured to implement any one or more of the method steps described above or herein. Optionally comprising a catalytic reactor configured to produce the organic acid. Optionally the catalytic reactor comprises any one or more of a dehydrogenater, a partial dehydrogenater, a partial oxidation catalyst, a partial dehydrogenation electrolyser, a partial oxidation electrolyser, an electrolyser. Or a a partial oxidation catalyst. Optionally comprising a conduit to the storage vessel. Optionally comprising a sensor configured to measure the parameter of the organic acid in the conduit. Optionally comprising a sensor configured to measure the parameter of the organic acid in the storage vessel. Optionally comprising a mixer configured to mix the diluent and organic acid. Optionally the mixer is at or near the entry of the organic acid and / or diluent into the storage vessel. Optionally comprising one or more variable speed pumps and / or valves. Optionally the one or more variable speed pumps and / or valves configured to control the combining of the diluent with the organic acid. Optionally comprising one or more of a flow rate sensor and a mass flow rate sensor configured to sense an amount of organic acid. Optionally comprising a flow rate sensor at an input to the electrolyser. Optionally comprising at least one sensor. Optionally the at least one sensor comprises a mass-flow sensor. Optionally the at least one sensor comprises a volume-flow sensor. Optionally the controller is configured to estimate a parameter based on one or more measurements. Optionally comprising at least one temperature sensor. Optionally the at least one temperature sensor configured to measure one or more of: a temperature of the organic acid; a temperature of the storage vessel; an ambient temperature; a forecast temperature. Optionally comprising an input representing a weather forecast. Optionally comprising a conduit between the diluent storage vessel and the storage vessel and / or an organic acid conduit to the storage vessel. Optionally the diluent storage vessel is an alcohol storage vessel, wherein the alcohol storage vessel is also configured to supply the electrolyser. Optionally the diluent storage vessel is water storage vessel. Optionally combining a conduit between one or more of the organic acid conduit or storage vessel and an output of a fuel cell. Optionally comprising a conduit from the input to the electrolyser to the storage vessel and / or the organic acid conduit to the storage vessel. Optionally an input of the fuel cell is connected to an output of a or the electrolyser. Optionally the sensor of the parameter of the organic acid is at a first location, and the diluent and the organic acid are combined at a second location, the second location downstream of the first location. Optionally comprising a sensor configured to measure an outflow from the storage vessel. Optionally comprising a sensor configured to measure the amount of diluent and / or organic acid within the storage vessel. In a further aspect, the invention provides a process for preparing hydrogen from an alcohol, the process comprising: (a) providing an electrolyser comprising an electrochemical cell comprising: i. an anode comprising a partial oxidation catalyst, ii. a cathode comprising a reduction catalyst, and iii. a separator between the anode and the cathode; (b) contacting the anode with a mixture of the alcohol and water; (c) applying a voltage to the electrochemical cell such that the alcohol is partially oxidized at the anode to produce a dehydrogenated product and a hydrogen precursor, and the hydrogen precursor passes through the separator and is converted to hydrogen at the cathode. Optionally the voltage is low. Optionally wherein the voltage applied to the electrolyser is less than 1.2 V. In another aspect, the invention provides an apparatus for generating hydrogen from an alcohol, the apparatus comprising: a) an electrolyser comprising an electrochemical cell comprising a vessel divided by a separator into a first volume and a second volume, wherein: i. the first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of an alcohol and water to produce a dehydrogenated product and a hydrogen precursor, and ii. the second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen; b) an energy source for applying a voltage to the electrochemical cell. In another aspect, the invention provides a process for generating electricity, the process comprising: c) providing an electrolyser comprising an electrochemical cell comprising: i. an anode comprising a partial oxidation catalyst, ii. a cathode comprising a reduction catalyst, and iii. a separator between the anode and the cathode; d) contacting the anode with a mixture of an alcohol and water; e) applying a voltage to the electrochemical cell such that the alcohol is partially oxidized at the anode to produce a dehydrogenated product and a hydrogen precursor, and the hydrogen precursor passes through the separator and is converted to hydrogen at the cathode, wherein the voltage applied to the electrochemical cell is less than 1.2 V; f) conveying the hydrogen to a fuel cell wherein the fuel cell converts the hydrogen to electricity and water. In another aspect, the invention provides an apparatus for generating electricity, the apparatus comprising: a) an electrolyser comprising an electrochemical cell comprising a vessel divided by a separator into a first volume and a second volume, wherein: i. the first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of an alcohol and water to produce a dehydrogenated product and a hydrogen precursor, and ii. the second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen; b) an energy source for applying a voltage to the electrochemical cell, wherein the voltage to be applied to the electrochemical cell is less than about 1.2 V; wherein in use, the hydrogen from the second volume is conveyed to the fuel cell to produce electricity. In another aspect, the invention provides a vehicle, the vehicle comprising: a) an electrolyser comprising an electrochemical cell comprising a vessel divided by a separator into a first volume and a second volume, wherein: i. the first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of an alcohol and water to produce a dehydrogenated product and a hydrogen precursor, and ii. the second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen; b) an energy source for applying a voltage to the electrochemical cell, wherein the voltage to be applied to the electrochemical cell is less than about 1.2 V; c) a fuel cell in fluid connection with the second volume; and d) a motor connected to the fuel cell; wherein, in use, the hydrogen from the second volume is conveyed to the fuel cell to produce electricity that is transmitted to the motor to drive the vehicle. In another aspect, the invention provides a vehicle, the vehicle comprising: a) an electrolyser comprising an electrochemical cell comprising a vessel divided by a separator into a first volume and a second volume, wherein: i. the first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of an alcohol and water to produce a dehydrogenated product and a hydrogen precursor, and ii. the second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen; (b)an energy source for applying a voltage to the electrochemical cell, wherein the voltage to be applied to the electrochemical cell is less than about 1.2 V; and (c) a combustion engine in fluid connection with the second volume; wherein, in use, the hydrogen from the second volume is conveyed to the combustion engine to drive the vehicle. In another aspect, the invention provides a mobile apparatus for generating hydrogen from ethanol, the apparatus comprising: a) an electrolyser comprising an electrochemical cell comprising a vessel divided by a separator into a first volume and a second volume, wherein: i. the first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of the ethanol and water to produce acetic acid and a hydrogen precursor, and ii. the second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen; b) an energy source for applying a voltage to the electrochemical cell. The following statements refer to any one of more of the above aspects. The system may also be referred to as a system for generating hydrogen from an alcohol. Where the system comprises a hydrogen fuel cell, the system may be referred to as a system for generating electricity. The system may be referred to as an integrated system where the interactions between the components of the system are integrated. The partial dehydrogenation process may be referred to as a partial oxidation process, or generally as an electrochemical process. The electrolyser may be or comprise an electrochemical cell (also referred to as an electrolytic cell), which is configured to operate as an electrochemical dehydrogenator for carrying out the partial dehydrogenation process. An electrolyser system may be provided comprising the electrolyser, wherein the electrolyser system is configured to operate the electrolyser, such as via a controller of the electrolyser system. The electrolyser system may be configured to apply and / or control a voltage applied to the electrolyser, such as via a controller of the electrolyser system. The electrolyser system may comprise, or be connectable to, an energy source, such as a battery, for applying a voltage to the electrolyser. The wider system may comprise the energy source, such as a battery, for applying the potential. The electrolyser system, or one or more components thereof, may be part of a unit or device. Optionally, an electrolyser unit is provided comprising the electrolyser and a controller for operating the electrolyser (e.g., for applying and / or controlling a voltage to the electrolyser). The electrolyser unit is optionally connectable to an energy source, such as a battery. The electrolyser unit is optionally arranged for fluid communication with other parts of the system so as to receive the feed stream and to provide the product and coproduct streams. The electrolyser may comprise a vessel divided by a separator into a first volume and a second volume, wherein: (i) the first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of an alcohol and water to produce a dehydrogenated product and a hydrogen precursor, and (ii) the second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen. The electrolyser may be operated by applying a voltage to the electrolyser such that the alcohol is partially oxidized at the anode to produce a dehydrogenated product and a hydrogen precursor, and the hydrogen precursor passes through the separator and is converted to hydrogen at the cathode. Optionally, where the electrolyser is provided as a heat source, the electrolyser system is configured to operate the electrochemical cell at a voltage above a thermoneutral voltage. Optionally, the electrolyser system is configured to operate the electrochemical cell above a voltage of about 0.2 volts (V). Optionally, the electrolyser system is configured to operate the electrochemical cell above a voltage of about 0.2 V and below a voltage of about 1.2 V. Optionally, the electrolyser system is configured to operate the electrochemical cell from above 0.2 V to about 1.2V, more optionally to about 1 V and more optionally still to about 0.5V. Optionally, where the electrolyser is not provided as a heat source, the electrolyser system is configured to operate the electrochemical cell at a voltage at or below a thermoneutral voltage. Optionally, the electrolyser system is configured to operate the electrochemical cell or electrolyser at or below a voltage of about 0.2 volts. Optionally, the infrastructure comprises a storage infrastructure for storing the co-product stream. Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings. As used herein the term "and / or" means "and" or "or", or both. As used herein "(s)" following a noun means the plural and / or singular forms of the noun. The term "comprising" as used in this specification and claims means "consisting at least in part of". When interpreting statements in this specification and claims which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner. In this specification, where reference has been made to external sources of information, including patent specifications and other documents, this is generally for the purpose of providing a context for discussing the features of the present invention. Unless stated otherwise, reference to such sources of information is not to be construed, in any jurisdiction, as an admission that such sources of information are prior art or form part of the common general knowledge in the art. For the purpose of this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be chronologically ordered in that sequence, unless there is no other logical manner of interpreting the sequence. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example only and with reference to the drawings in which: Figure 1 shows a general example of the system 100. Figure 2 drive a vehicle. shows an example diagram of use of the process of the system to Figure 3a to 3e show example implementations of the system 100. Figure 4 shows an example of a diluent process. Figure 5 shows another example of a diluent process. Figure 6 shows another example of a diluent process. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS According to various aspects of the various examples as illustrated in Figures 16, there is provided a method and / or system for the storage of a dehydrogenated product, such as an organic acid, which will now be described. In a broad sense, the storage of the dehydrogenated product comprises combining or mixing the dehydrogenated product with one or more diluents. Advantageously these diluents may lower the freezing point of the resulting mixture to prevent freezing of the dehydrogenated product. Freezing of the dehydrogenated product is undesirable because it limits a system's ability to use and / or transfer the dehydrogenated product. Increasing awareness about the environment effects of fossil fuels and resulting societal shift away from use of fossil fuels has driven the search for alternative clean fuel sources. A valuable alternative fuel is hydrogen. Hydrogen may be utilised in a fuel cell to generate clean energy by reacting hydrogen and oxygen in which the only by-product is water. However, hydrogen has disadvantages that have limited its widespread use. Hydrogen is a highly flammable gas that, due to its small atomic size, may permeate or leak through storage containers. Consequently, storage of hydrogen can be costly and dangerous. Further, generation of hydrogen can be energy intensive and produces pollution in itself, which reduces the viability of hydrogen as a clean energy source. One solution that has been adopted is the use of liquid organic hydrogen carriers (LOHCs), such as toluene / methylcyclohexane. LOHCs may provide stable source of hydrogen that is safe for storage and may generate hydrogen on demand by reaction with a catalyst. However, LOHCs are specialised chemicals that must be synthesised, potentially through wasteful processes. Further, when consumed in the generation of hydrogen, LOHCs create a by-product that must be regenerated or disposed of potentially leading to large volumes of by-product that must be transported and stored / disposed of. Another alternative fuel source are direct alcohol fuel cells. A direct alcohol fuel cell utilises an alcohol, e.g. methanol or ethanol, in an electrochemical cell containing an anode and cathode to generate electricity. The alcohol and water react at the anode to produce carbon dioxide and electrons and protons. The protons are transported to the cathode where the protons react with oxygen to produce water. An advantage of the direct alcohol fuel cells is that it uses alcohols that are a low-cost and readily available commodity chemicals, and the only liquid by-product is water. Direct alcohol fuel cells do, however, generate carbon dioxide. Additionally, direct alcohol fuel cells can suffer from a short life span due to the susceptibility of the cathode, e.g., to catalyst poisoning by the alcohol permeating from the anode to the cathode. The patent applicant has developed a catalytic process that allows an alcohol carrier, such as ethanol, to be electrochemically dehydrogenated to produce hydrogen and a dehydrogenated co-product, such that the hydrogen can be carried in a stable and liquid form. In one example application, this allows the hydrogen carrier to be transferred to and carried by vehicles to provide a mobile source of fuel for motive power of the vehicles. At a very broad level, this is the same as petrol or diesel that is carried by a passenger car as a fuel used by the internal combustion engine of the passenger car. To extract the hydrogen from the alcohol carrier, an on-vehicle electrochemical dehydrogenation process (also referred to as an oxidation process) is carried out that results in hydrogen gas being made available for use in a hydrogen fuel cell. In some other applications, the process may not transfer the hydrogen to a hydrogen fuel cell. The hydrogen may be captured and stored for other purposes (e.g., chemical or biological). The dehydrogenation process is a selective partial dehydrogenation process such that the co-product generated in addition to the hydrogen may have value as a commodity chemical (e.g., an organic acid). Where ethanol is the carrier, the co-product is acetic acid, which could be sold as a chemical feedstock (including for biological purposes) or as an ingredient in food or feed production, or alternatively re-hydrogenated for further use in the liquid hydrogen fuel cycle. Hence, the co-product (organic acid) may need to be handled and stored at the location where it is produced, such as onboard a vehicle, and this presents a unique set of circumstances and desiderata which the present invention seeks to address. Figure 1 shows an example system 100 comprising an electrolyser 300. The electrolyser comprises an electrochemical cell operable as an electrolytic cell and more specifically as an electrochemical dehydrogenator for producing hydrogen and a dehydrogenated product from an alcohol via an electrochemical dehydrogenation process. The electrochemical process and the electrolyser are described in greater detail elsewhere in this specification. In general, the electrolyser comprises an anode and a cathode (i.e., the electrodes), and a separator, such as a membrane, between the anode and the cathode. The electrolyser may be part of an electrolyser system, which is configured to control the operation of the electrolyser, such as by applying and / or controlling a potential applied to the electrolyser. Optionally, the electrolyser system comprises a controller for such purposes. The electrolyser system may provide for various connections or couplings for integration with the other parts of the system. For example, the electrolyser system may be arranged to couple the electrolyser to an energy source, such as a battery, for applying a potential to the electrolyser (i.e., cell voltage across the electrodes). The electrolyser system may also provide for fluid connections with other parts of the system. In particular, the electrolyser 300 is arranged to receive a feed stream 102 comprising an alcohol and to produce a product stream 104 comprising hydrogen and coproduct stream 106 comprising a dehydrogenated alcohol (i.e., the dehydrogenated product or organic acid). The electrolyser and one or more other components of the electrolyser system may be part of a unit or device. Optionally, an electrolyser unit is provided comprising the electrolyser 300 and a controller for operating the electrolyser (e.g., for applying and / or controlling a potential to the electrolyser). The electrolyser unit is optionally connectable to an energy source, such as a battery. The electrolyser unit is optionally arranged for fluid communication with other parts of the system so as to receive the feed stream and to provide the product and co-product streams. The hydrogen may be provided to a hydrogen fuel cell 500 for the generation of electricity, as discussed elsewhere in this specification, or provided for other purposes (e.g., combusted, or otherwise used or sold as feedstock chemical for chemical or biological purposes). It may also be desirable, or indeed necessary, for the dehydrogenated product to be handled and stored for a time at the location where the reaction process takes place before subsequent use or distribution. For example, the dehydrogenated product may be recycled within an LOHC cycle (i.e., re-hydrogenated) or, as is preferred, at least some of the dehydrogenated product may be provided as a saleable chemical for other purposes (e.g., chemical or biological). Hence, the system 100 comprises infrastructure 200 for handling and / or storing the co-product stream 106. The co-product stream 106 is conveyed by a handling infrastructure 202, which may include for example one or more pumps, fluid lines (e.g., tubes, pipes and the like), metering devices, flow measurement and control devices, and other such equipment as will be appreciated, from the electrolyser system to a storage infrastructure 204 (e.g., one or more storage units, vessels, containers, tanks and the like) where the dehydrogenated product may be stored as desired for later use or distribution. The storage infrastructure may be for example an adaptable storage device. The handling and storage infrastructure 202, 204 may be together referred to simply as the infrastructure 200. Optionally, the dehydrogenated product is an organic acid, such as formic acid, acetic acid, propionic acid, or butyric acid, produced by selective partial dehydrogenation (oxidation) of methanol, ethanol, propanol, or butanol, respectively. The freezing point of substances such as these may be sufficiently high as to potentially present a handling and / or storage challenge in the conditions where they are produced, particularly when produced as a pure stream or handled as such (e.g., after purification). Indeed, in some environments the ambient temperature may be, or drop to (at least temporarily or intermittently), below the freezing point of the dehydrogenated product, causing the formation of crystals in the co-product stream during handling and / or storage, and ultimately leading to a phase transition of the dehydrogenated product from liquid to solid, i.e., freezing. This can be problematic during handling as the infrastructure may be designed to manage fluid flow (e.g., liquid, vapour, or a mixture thereof) by means of pumps, fluid lines and the like, which may be unable to operate if the dehydrogenated product freezes or begins to do so. Even the formation of crystals among a largely liquid body of co-product can be problematic as this may still cause blockages or otherwise interfere with the operation of system componentry, such as pumps. Equally, it may be desirable to maintain the dehydrogenated product in a liquid state during storage so that the product may be emptied, such as by draining or pumping, for subsequent use or distribution (as described elsewhere). If the stored product were to freeze, then significant energy and time may be consumed thawing the contents to bring it into a desired state for further handling (e.g., emptying), such as by using an external heat source. Due to enthalpy of fusion, more energy may be required to melt a frozen quantity of dehydrogenated product than would be required to simply maintain that quantity above freezing. The electrochemical dehydrogenation process is a process for partially oxidising a mixture of alcohol and water to produce product stream comprising hydrogen and a coproduct stream comprising a dehydrogenated product (e.g., an organic acid). One example of this reaction generally may be represented by the following reactions (in which n is, e.g., 0 to 8): Anode reaction: CH3(CH2)nOH + H2O -CH3(CH2)n-1COOH + 4H+ + 4e - (in acidic conditions) CH3(CH2)nOH + 4OH - - CH3(CH2)n-1COOH + 3H2O + 4e - (in alkaline conditions) Cathode reaction: 4H+ + 4e - — 2H2 (in acidic conditions) 4H2O + 4e - — 4OH - + 2H2 (in alkaline conditions) Overall reaction (both acidic and alkaline conditions) CH3(CH2)nOH + H2O -CH3(CH2)n-1COOH + 2H2. The partial oxidation may be contrasted with full oxidation wherein the alcohol is fully oxidised to carbon dioxide or a carbonate. Selectivity for partial oxidation (vs full oxidation) is affected by various factors such as the choice of catalyst and voltage applied to the electrolyser. Generally, a lower voltage applied to the anode will favour the partial oxidation. The alcohol functions as an organic hydrogen carrier which may be oxidised to produce hydrogen via a hydrogen precursor. The alcohol is an organic compound comprising one or more hydroxyl groups attached to an alkyl group. The alcohol may be a straight chain alcohol, such as n-propanol, or a branched alcohol, such as iso-propanol. In some embodiments, the alcohol is a C1-8 alcohol. In some embodiments, the alcohol is a C1-5 alcohol. Optionally, the alcohol is a C1-3 alcohol, including but not limited to, methanol, ethanol, n-propanol, isopropanol, methylene glycol, ethylene glycol, propylene glycol, gylcerol or a combination of any two or more thereof. In some embodiments, the alcohol is ethanol. In some embodiments, the alcohol is a biofuel derived from a biological source, such as bioethanol derived from, e.g., biomass. The alcohol may be supplied to the anode as a liquid, a vapour or a combination thereof. The dehydrogenated product is a partial oxidation product of the alcohol. The dehydrogenated product is optionally a carboxylic derivative of the alcohol. For example, when the alcohol is ethanol, the dehydrogenated product may be acetic acid. Those persons skilled in the art will appreciate that depending on the conditions, e.g. at a basic pH, the carboxylic acid may instead exist as the corresponding acetate salt. As used herein, terms such as "carboxylic acid", "acetic acid" and other related terms are intended to describe the dehydrogenated product in the acid and acetate forms, as appropriate. The dehydrogenated product may include an aldehyde derivative of the alcohol. In some examples, the dehydrogenated product is a carboxylic acid, an aldehyde or a combination thereof. For example, the carboxylic acid may be a C1-5 carboxylic acid, including but not limited to, formic acid, acetic acid, glycolic acid, glyoxylic acid, oxalic acid, propanoic acid, glyceric acid, lactic acid, acrylic acid, butanoic acid, pentanoic acid or a combination of any two or more thereof. In some examples, the co-product stream comprises at least about 80% of the dehydrogenated product (e.g., organic acid). In some examples, the co-product stream comprises at least about 90% of the dehydrogenated product (e.g., organic acid).In some examples, the co-product stream comprises at least about 95% of the dehydrogenated product (e.g., organic acid). In some examples, the co-product stream comprises at least about 98% of the dehydrogenated product (e.g., organic acid). In some examples, the coproduct stream comprises at least about 99% of the dehydrogenated product (e.g., organic acid). In some examples, the co-product stream comprises at least about 80% of a carboxylic acid, an aldehyde or a combination thereof. In some examples, the co-product stream comprises at least about 90% of a carboxylic acid, an aldehyde or a combination thereof. In some examples, the co-product stream comprises at least about 95% of a carboxylic acid, an aldehyde or a combination thereof. In some examples, the co-product stream comprises at least about 98% of a carboxylic acid, an aldehyde or a combination thereof. In some embodiments, the co-product stream comprises at least about 99% of a carboxylic acid, an aldehyde or a combination thereof. In some examples, the alcohol is a C1-3 alcohol and the co-product stream comprises at least about 80% of a C1-3 carboxylic acid, a C1-3 aldehyde or a combination thereof. In some examples, the alcohol is a C1-3 alcohol and the co-product stream comprises at least about 90% of a C1-3 carboxylic acid, a C1-3 aldehyde or a combination thereof. In some examples, the alcohol is a C1-3 alcohol and the co-product stream comprises at least about 95% of a C1-3 carboxylic acid, a C1-3 aldehyde or a combination thereof. In some examples, the alcohol is a C1-3 alcohol and the co-product stream comprises at least about 98% of a C1-3 carboxylic acid, a C1-3 aldehyde or a combination thereof. In some examples, the alcohol is a C1-3 alcohol and the co-product stream comprises at least about 98% of a C1-3 carboxylic acid, a C1-3 aldehyde or a combination thereof. In some examples, the alcohol is ethanol and the co-product stream comprises at least about 95% of acetic acid, acetaldehyde or combination thereof. In some examples, the alcohol is ethanol and the co-product stream comprises at least about 98% of acetic acid, acetaldehyde or combination thereof. In some examples, the alcohol is ethanol and the coproduct stream comprises at least about 99% of acetic acid, acetaldehyde or combination thereof. In some examples, the product stream consists of the dehydrogenated product (e.g., organic acid), wherein the dehydrogenated product is a carboxylic acid, an aldehyde or a combination thereof. In some examples, the product stream consists essentially of the dehydrogenated product, wherein the dehydrogenated product is a carboxylic acid, an aldehyde or a combination thereof. In some examples, the product stream consists of a carboxylic acid. In some examples, the product stream consists essentially of a carboxylic acid. As described, the dehydrogenated product may be a valuable commodity product, such as acetic acid. Accordingly, in some embodiments, the invention provides a process for partially oxidising an alcohol to produce a dehydrogenated product, wherein the dehydrogenated product is a commodity product. Alternatively, in some embodiments, the dehydrogenated product is reduced back to the alcohol such that it may be reused as a liquid organic hydrogen carrier. The hydrogen precursor is reduced to hydrogen at the cathode. The hydrogen precursor may be, e.g., a proton or water. The electrochemical process may also be seen as a process for the production of a dehydrogenated product from an alcohol, comprising the steps of (i) contacting the alcohol with the anode and (ii) applying a low voltage to an anode to partially oxidise the alcohol to produce the dehydrogenated product. The electrochemical process may also be seen as a process for the production of hydrogen from an alcohol, comprising the steps of (i) contacting the alcohol with the anode, (ii) applying a low voltage to the anode to partially oxidise the alcohol to produce a hydrogen precursor, and (iii) reducing the hydrogen precursor to hydrogen at a cathode. In some examples, the product stream comprising hydrogen comprises about 2 vol% or less CO2. In some examples, the product stream comprising hydrogen comprises less than about 0.5 vol% CO2. In some examples, the product stream comprising hydrogen comprises less than 0.1 vol% CO2. In some examples, the product stream comprising hydrogen comprises less than 10 ppm CO. In some examples, the product stream comprising hydrogen comprises 2 vol% or less CO2 and less than 10 ppm CO. A preferred example of an electrolyser 300 will now be described. The electrolyser 300 may be part of the electrolyser system for partially oxidising an alcohol to produce hydrogen and a dehydrogenated product. The electrolyser may be arranged for connection to an energy source, such as a battery, for applying a potential to the electrolyser. Optionally, this potential is applied and / or controlled via an electrolyser system or controller as already described. In some examples, the system comprises the electrolyser and the energy source. The electrolyser comprises a vessel divided by a separator into a first volume and a second volume. The first volume houses an anode comprising a partial oxidation catalyst capable of partially oxidizing a mixture of an alcohol and water to produce a partial dehydrogenation product and a hydrogen precursor. The second volume houses a cathode comprising a reduction catalyst capable of converting the hydrogen precursor to hydrogen. An anode of the electrolyser comprises a partial oxidation catalyst. The term "partial oxidation catalyst" as used herein refers to any catalyst capable of partially oxidising the alcohol to produce a hydrogen precursor and a dehydrogenated product. A person skilled in the art could select a suitable catalyst and appropriate conditions for achieving partial oxidation. Suitable catalysts include, but are not limited to, a transition metal or a transition metal oxide, such as a Pd catalyst, Pt catalyst and / or a Pt-Sn catalyst. The anode may comprise the catalyst embedded on a substrate. Suitable substrates may include a carbon-substrate (such as graphite, carbon black or carbon paper), a Ti substrate and / or Ni substrate. The anode may comprise 1 to 50 wt% of the catalyst, e.g., about 5 to 40 wt%, 10 to 30 wt%, 15 to 25 wt% or 20 wt%. The catalyst may be in the form of nanoparticles, e.g. particles having an average particle size of about 1 to 10 nm. In some embodiments, the anode comprises Pd nanoparticles on carbon black. In some embodiments, the anode comprises 20 wt% Pd nanoparticles on carbon black. The partial oxidation catalyst may also be in the form of a single atom catalyst. A cathode of the electrolyser comprises a reduction catalyst. The term "reduction catalyst" as used herein refers to any catalyst capable of reducing the hydrogen precursor to hydrogen (i.e. a reduction catalyst). A person skilled in the art could select a suitable catalyst and conditions to reduce the hydrogen precursor to hydrogen. Suitable catalysts include, but are not limited to, a Pt catalyst, a Ni catalyst a Ru catalyst, a Fe catalyst or a combination of two or more thereof. The cathode may comprise the reduction catalyst embedded on a substrate. Suitable substrates may include a carbon substrate (such as graphite, carbon black or carbon paper), a Ti substrate and / or an Ni substrate. The reduction catalyst may be in the form of nanoparticle, e.g. particles having an average particle size of about 1 to 10 nm. The reduction catalyst may be in the form of a single atom catalyst. The electrolyser comprises a separator between the anode and cathode. The separator functions to restrict flow of fluids between the anode to the cathode. Flow of fluids from the anode to the cathode, or vice versa, can reduce the efficiency of the process, e.g., exposing the cathode to the alcohol can lead to poisoning of the reducing catalyst and reduce the efficiency and lifespan of the catalyst. Ideally, only the hydrogen precursor produced at the anode may pass through the separator to react at the cathode. In some embodiments, the separator is a porous non-conductive membrane, such as Celgard microporous polymer. In some embodiments, the separator is an ionically-conductive membrane, such as a cation exchange membrane, an anion exchange membrane or a proton exchange membrane (PEM). Suitable ionically-conductive membranes include, but are not limited to, Nation, Piperion, Sustainion and Fumatech. In some examples, the PEM comprises a polybenzimidazole (PBI) polymer. In some examples, the PEM is a phosphoric acid doped PBI membrane or an ion-pair PBI membrane. Those persons skilled in the art will appreciate other conventional separators known in the art may be useful in the invention. Advantageously, an ionically conductive membrane may also function as the electrolyte removing the need for a further electrolyte. In some embodiments, there is a fluid between the separator and the cathode (e.g. in the second housing) to provide a medium for transporting the hydrogen precursor to the cathode. For example, when the separator is an anion exchange membrane, the electrolyser may comprise a fluid such as water or water vapour between the separator and the cathode. Advantageously, when the separator is a PEM, the hydrogen precursor (e.g. proton) may directly contact the cathode without the need for a fluid. The electrolyser may comprise an electrolyte chosen from those known to those persons skilled in the art. Electrolytes include acidic electrolytes, basic electrolytes, salt electrolytes and ionic liquid electrolytes. While a vast array of acids, bases, or ionic liquids can be used as electrolytes, electrochemical processes are affected by the choice of electrolytes and in particular, are different in basic vs acidic electrolytes. In some embodiments, the electrolyte is an aqueous solution comprising a salt, such as a potassium or sodium salt. In some embodiments, the potassium or sodium salt is a chloride or hydroxide salt. In some embodiments, the electrolyte is a 1-30 wt% aqueous salt solution, e.g., a 1-30 wt% aqueous KCI or KOH. The potential is selected to favour partial oxidation of the alcohol (vs full oxidation). For this purpose, generally the potential should be as low as possible. For example, from above 0 to about 1.2 V, about 0.01 to 0.5 V or about 0.05 to 0.2 V. In some examples, the potential is less than 1.0 V. In some examples, the potential is less than 0.8V. When operated in combination with a fuel cell, the potential applied to the anode should be lower than the output voltage of the fuel cell. Surprisingly, the inventors have discovered the electrolyser may be operated at a low potential, i.e., at a potential less than about 1.2 V. In situations where the electrolyser is operated as a heat source, the potential is optionally above a thermoneutral voltage, which may be about 0.2 V. Optionally the potential is within a range having a lower bound defined by the thermoneutral voltage (for the purposes of generating heat) and an upper bound selected to favour partial oxidation of the alcohol. The operating conditions for the electrolyser may be selected according to the intended application and components of the system. For example, when the alcohol is supplied to the anode as a liquid, the electrolyser is optionally operated at a temperature of less than, or at most, about 100°C and more optionally within a range of about 25 to 78°C. When the alcohol is supplied to the anode as a vapour, the electrolyser is optionally operated at a temperature of less than, or at most, about 250°C, or less than, or at most, about 200°C, or less than, or at most, about 150°C and more optionally at a temperature of about 55 to 110°C. Generally, the electrolyser is operated in a temperature range of about 0 to 250°C, about 0 to 200°C or about 0 to 150°C. Generally, the electrolyser is operated in at a pressure of about 1 to 50 bar. In some embodiments, the electrolyser is operated in at a pressure of about 10-20 bar. In some examples, the electrolyser is operated at a temperature in a temperature range of about 50 to 250°C, 50 to 200°C, 50 to 150°C, 50 to 100°C, 80 to 250°C, 80 to 200°C, 80 to 150°C, 80 to 100°C, 100 to 250°C, 100 to 200°C, 100 to 150°C, 150 to 250°C or 150 to 200°C. In some examples, the electrolyser is operated at a temperature of about 55 to 110°C. In some examples, the electrolyser is operated at a temperature above about 50°C. In some examples, the electrolyser is operated at a temperature above about 60°C, 70°C, 80°C, 90°C or100°C. The electrolyser may be operated at a pH of 0 to 14. The preferred pH range may be selected based on various factors, such as the components of the system and desired hydrogenation product(s). For example, in some embodiments, the electrolyser comprises a Nation separator with no additional electrolyte and is operated at a pH of about 0 to 2. In some other embodiments, the electrolyser is operated at a pH of 7 or above to minimise formation of a condensation by-product of the dehydrogenated product (e.g., ethyl acetate when the alcohol is ethanol). Use of an apparatus according to the invention in an electric vehicle is shown in Figure 2. In this figure, a feed stream 102 (liquid fuel) is conveyed to an electrolyser 300 (dehydrogenator) to produce a hydrogen stream 104 and a dehydrogenated product stream 106. The hydrogen stream 104 produced in the electrolyser 300 is conveyed to a fuel cell 500, which produces electricity 502 to drive a vehicle. Optionally, a portion 502a of the electricity produced by the fuel cell 500 may be transmitted back to the electrolyser 300 to drive the electrochemical process. In this example, the fuel cell 500 also produces heat 504 and water 506, which may be conveyed to the electrolyser 300 as shown. The apparatus may comprise containers (e.g. tanks) for storing fluids to be used in the apparatus and / or fluids produced by the apparatus. For example, the apparatus may comprise a first container for storing the alcohol and / or a second container for storing water. The apparatus may further comprise a third container for mixing the alcohol and water before addition to the electrolyser. In these embodiments, the first and second container are in fluid connection with the third container and the third container is in fluid connection with the first housing of the electrochemical cell. Alternatively, the alcohol and water may be conveyed directly to the electrolyser. In these embodiments, the first and second containers are in fluid connection with the first housing of the electrochemical cell. The apparatus may comprise a container for storage of the dehydrogenated product produced by the electrolyser. Those persons skilled in the art will appreciate the first, second, 5 third and fourth containers as described above are exemplary. Other configurations of storage containers are within the scope of the invention, e.g., the use of multiple containers for each component. Containers suitable for use in the apparatus may be selected depending on the intended function, e.g., whether the container is for short-term or longer-term storage, mobile or stationary applications and the required volume. 10             Fluids in the apparatus may be conveyed around the apparatus with conventional means, e.g. pumps. For example, the apparatus may comprise one or more pumps located between the containers, electrolyser and / or fuel cell. In some embodiments, the alcohol stored in the first container and water stored in the second container are pumped to the third container, then the mixture is pumped from the third container to the first housing of 15 the electrochemical cell. The apparatus may further comprise a control unit for controlling the one or more pumps. The function of the control unit is to increase, decrease or stop the flow of fluids among components in the apparatus as required. For example, flow of the mixture of alcohol and water into the electrolyser may be modulated depending on the rate in which the 20 mixture is consumed by the electrolyser. Accordingly, the control unit may be operated in combination with sensors in the apparatus. For example, the first and / or second housings of the electrochemical cell may comprise level sensors to detect the amount of fluid in each housing. The first, second, third and / or fourth containers may also comprise level sensors to detect the amount of fluid in each container. Flow sensors may also be used to detect 25 the rate of flow of a fluid between components. Sensors may also be useful independent of a control unit to monitor the apparatus, e.g., to monitor if amount of the alcohol and / or water in the apparatus is low and must be refilled. The hydrogen produced in the electrolyser may be convey to a storage tank for transport or storage. Accordingly, in some embodiments, the apparatus comprises a fifth 30 container for storing the hydrogen, wherein the fifth container is in fluid connection with the electrolyser. As discussed above, optionally the amount of contaminants in the hydrogen from the electrolyser is minimised. For some applications, the hydrogen produced by the electrolyser may be cleaned, e.g. to further reduce contaminants such as carbon dioxide or ethanol, before being conveyed to the power generating device. Accordingly, the apparatus may further comprise a gas cleaner between the electrolyser and power generating device. Optionally, the hydrogen conveyed to the fuel cell comprises less than about 2 ppm CO2 and / or less than about 0.2 ppm CO. The apparatus comprises an energy source for applying a potential to the electrolyser (i.e. to the electrochemical cell or cells). When the electrolyser is operated in combination with a fuel cell that transmits electricity back to the electrolyser, the energy source may function as a "starter" to initiate operation of the process. In some embodiments, the battery is used as the energy source to apply a potential to the electrolyser. In some embodiment, the process is a stationary plant for producing the dehydrogenated product, e.g., a commodity product. The apparatus may be a mobile unit. For example, the electrolyser may be operated with a power generating device, e.g. a combustion engine or fuel cell, to convert the hydrogen to power the vehicle, e.g., drive the motor. In some embodiments, the vehicle is a zero-emission vehicle, such as a zero-emission car. For this purpose, the dehydrogenated product (and any other by products) may be removed from the electrolyser and the electrolyser recharged with an alcohol to refuel the process. Additionally or alternatively, the apparatus may be a mobile plant for producing hydrogen and / or a dehydrogenated product. The following non-limiting examples are provided to illustrate the present invention and in no way limit the scope thereof. In some examples, the electrolyser comprises a single electrochemical cell as described above. In some other examples, the electrolyser comprises two or more electrochemical cells operating in series. As already discussed, the electrolyser may operate in combination with a power generating device for converting the hydrogen to power, e.g. a combustion engine or fuel cell. Accordingly, in some embodiments, at least a portion of the hydrogen may be conveyed to a combustion engine. The combustion engine may be for powering a vehicle, such as a car, ship, train or plane. In some examples, at least a portion of the hydrogen produced in the electrolyser is conveyed to a fuel cell in which the hydrogen is converted to electricity and water. The combination of electrolyser and fuel cell provides a closed system for producing hydrogen and converting the hydrogen to electricity (i.e. the hydrogen produced in the electrolyser is utilised directly within the system). Accordingly, the combination of electrolyser and fuel cell may be utilised in mobile applications, e.g. for powering a vehicle wherein the vehicle is fuelled by the alcohol. For this purpose, the vehicle may be refuelled by replenishing the alcohol consumed by in the electrolyser. Alternatively, the combination of electrolyser and fuel cell may be utilised in stationary applications. Advantageously, producing hydrogen in a separate component (the electrolyser) from the fuel cell reduces poisoning of the fuel cell cathode, e.g. by the alcohol, compared to direct ethanol fuel cells. In some examples, the fuel cell is a single cell. In some other examples, the fuel cell is two or more cells operating in series. The operating conditions for the hydrogen fuel cell may be selected according to the intended application and components of the system. The temperature range for the fuel cell may be dependent upon, for example, the fuel cell technology and the pressure of the substrate feed, and as such could be as wide as from about 70°C to about 1000°C. The preferred operating temperature could be from about 70°C to about 200°C, such as for low temperature polymer electrolyte membrane (PEM) fuel cells. The preferred operating temperature could be from about 600°C to about 1000°C, such as for solid oxide fuel cells. The electrolyser may be directly connected to the fuel cell. Alternatively, there may be an intermediate component between the electrolyser and the fuel cell, e.g. a gas cleaner. For some applications, the hydrogen produced by the electrolyser is cleaned, e.g. to remove contaminants such as carbon dioxide or ethanol, before being conveyed to the power generating device. Accordingly, the apparatus may further comprise a gas cleaner between the electrolyser and power generating device. Some or all of the electricity produced by the fuel cell may be transmitted to operate the electrolyser. Advantageously, in those embodiments, the electrolyser and fuel cell combination may be self-sufficient. In those embodiments in which all of the electricity produced by the fuel cell is transmitted to the electrolyser, the remaining hydrogen may be conveyed to a tank for transport or storage or conveyed to a separate device for converting the hydrogen to power. In some embodiments, at least a portion of the hydrogen may be conveyed to multiple fuel cells, e.g., a small fuel cell for powering the electrolyser and a larger fuel cell for producing electricity for external applications. The electricity produced by the fuel cell may be used for powering a vehicle, such as a land vehicle (e.g. a car truck or train), ship or aircraft. In some embodiments, the fuel cell may be used for driving the motor of the vehicle. Optionally, the outlet pressure from the electrolyser is higher than the fuel cell inlet pressure. For example, the outlet pressure from the electrolyser may be about 2 to 10 bar higher than the fuel cell inlet pressure. In some embodiments, the apparatus further comprises a hydrogen buffer volume between the electrolyser and fuel cell. The buffer volume is a space in which hydrogen may collect before entering the fuel cell. The size of the buffer volume may be selected depending on the system requirements, e.g., the rate of hydrogen production in the electrolyser versus hydrogen consumption by the fuel cell. For example, a minimal buffer volume may be necessary if the rate of hydrogen product is similar to the rate of hydrogen consumption, while a larger buffer volume (or buffer tank) may be useful if there is a significant different between the rate of hydrogen production versus consumption. The purpose of the buffer volume is to ensure constant flow of hydrogen to the fuel cell. Additionally or alternatively, the electricity produced by the fuel cell may be transmitted to a battery for later use. Accordingly, in some examples, the system comprises the electrolyser in fluid connection with a fuel cell. The system may comprise an energy source for applying a potential to the electrolyser. When the electrolyser is operated in combination with a fuel cell that transmits electricity back to the electrolyser, the energy source may function as a "starter" to initiate operation of the process. In some examples, the system further comprises a battery for storage of the electricity produced by the fuel cell. In some embodiments, the battery is used as the energy source to apply a potential to the electrolyser. The systems described may be implemented on a vehicle, or floating or fixed platform. Figures 3a-e show various examples of such platforms incorporating the system. The system may be a unit for example, that is secured to, carried, or supported on, a platform including for example any of the following: Figure 3a shows a first example implementation in which the system 100 is carried by a marine vessel (e.g., a ship). Figure 3b shows a second example implementation in which the system 100 is carried by a floating platform (e.g., an offshore rig). Figure 3c shows a third example implementation in which the system 100 is carried by a passenger motor vehicle (e.g., a car, such as a fuel cell electric vehicle). Figure 3d shows a fourth example implementation in which the system 100 is carried by a larger commercial vehicle (e.g., a truck). Figure 3e shows a fifth example implementation in which the system 100 is carried by a flying vehicle (e.g., an aeroplane). Optionally, the system in these onboard applications comprises both the electrolyser system for carrying out the dehydrogenation process and the hydrogen fuel cell for generating electricity using the hydrogen from the electrolyser system. Optionally, the system further comprises the battery, which may be electrically coupled to the hydrogen fuel cell for charging. In turn, the battery may be used to provide motive power for the vehicle, such as via an electric motor (as per a fuel cell electric vehicle). The battery may also be used to provide power to the electrolyser system for carrying out the electrochemical dehydrogenation process. In other words, the battery may be electrically coupled to a motor and the electrolyser system and configured to provide a portion of the total charge to each. In other implementations, the vehicle or platform may not have a hydrogen fuel cell and instead achieve motive power through, say, combustion of the produced hydrogen. As will be appreciated, moving platforms may encounter a range of environments and temperatures and may have limited access to external power and resources for managing the temperature of the system and in particular that of the co-product, which renders the benefits of the present invention all the more relevant for such applications. The latter consideration may also be true for fixed or floating platforms in remote locations, such as an offshore floating platform (e.g., Figure 3b). Additionally, there may be a further desire for fast and efficient refuelling for these mobile applications, which in the present example may include the unloading (emptying) of accumulated co-product and the loading of a supply of the alcohol-containing substrate chemical to provide the feed stream for the electrolyser system. It will be clear, for example, that the driver of a passenger car is unlikely to want to wait for an accumulation of co-product to be thawed when refuelling, if the ambient temperature happens to have fallen below the freezing point of the co-product. This may be no more desirable from a commercial perspective for a truck, plane or ship. As described the catalytic process produces a by-product, such as an organic acid. A particular example is acetic acid, which will be described here. However, the process is applicable to other organic acids, and may be applied to other by-products where a freezing point should be increased or decreased. The process has particular application with the patent applicant's catalytic process, for example because of the availability of water and / or ethanol as diluents. However, other processes or electrolysis types may also be advantaged by using the described diluent system. In a broad example, the system and method improve the storing and / or handling of an organic acid or organic acid containing product by decreasing the effective freezing point of the stored liquid to mitigate freezing when subject to current or expected environmental conditions, thereby advantageously maintaining the stored liquid in a flowable (e.g., liquid) condition. A flowable condition may be any phase capable of flowing to enable for example pumping and the like. This may include a liquid state and phase changing intermediates like slurries. For the purposes of the present discussion, 'product' refers to the co-product comprising the organic acid, which may be provided as the co-product stream (described above). The method comprises monitoring an environmental parameter, typically a temperature, and a parameter of the product (e.g., organic acid), typically indicative of an amount of organic acid. The environmental parameter provides an indication of the external environment, such as the external temperature, and therefore of the risk or potential for the organic acid to freeze. The product parameter provides an indication of the amount (e.g. volume and / or concentration) of product, preferably of organic acid, present in the system. This allows a determination of the amount (e.g. volume and / or concentration) of the diluent required, or desired to be combined with the organic acid to, for example, ensure the mixture remains liquid (or at least in flowable condition) for an expected temperature range. In other examples, the diluent may be selected to ensure the mixture remains liquid (or at least in flowable condition) at a current or expected temperature. In some examples, the aim may be to maintain the organic acid as a liquid or in a flowable condition for the desired environmental conditions, while permitting the diluent to freeze but preferably the mixture is maintained as a liquid or in a flowable condition for the desired environmental conditions. Once an amount of diluent is determined, this diluent is mixed with the organic acid to create a mixture with a lower freezing point. This method reduces the freezing point such as relative to that of the pure organic acid by mixing the acid with another diluent. By selecting a suitable diluent for the organic acid, the freezing point of the resulting mixed solution is lower than that of the pure stream of organic acid. An appropriate diluent to decrease the freezing point of certain organic acids should be selected based on experimentation or data. Once selected, the freezing point reduction that can be achieved by blending a known volume of diluent into a known volume of acid can be calculated. For example, acetic acid has a freezing point of about 17°C, while ethanol has a freezing point of about -114°C. By using the ethanol as a diluent of the acetic acid, it is possible to lower the freezing point of the acetic acid. For example, adding approximately 20% ethanol to acetic acid reduces the freezing point to about -4°C. Adding approximately 30% ethanol to acetic acid reduces the freezing point to about -17°C. Further increases in the ethanol concentration are likely to lower the freezing point to a temperature where acetic acid precipitation is not an issue in any climate. Advantageously, obtaining a measurement of the organic acid allows the amount of diluent added to the organic acid to be minimised (to maintain purity such that the distillation or filtering process to purify the organic acid is reduced) while avoiding freezing of the organic acid. This is because the freezing point of the mixed solution can be lower (with the correct selection of diluent) than the pure organic acid. This allows the system to deliberately maintain an acid solution as a liquid or in a flowable condition through the addition of a diluent to a produced acid stream in a temperature dependent manner so as to maintain the organic acid product as a liquid during its handling and storage. In some examples, the product is a substantially pure stream of organic acid. In other examples, the product comprises the organic acid among other substances, such as contaminants, water, or other diluents. As described previously the organic acid, or input to the diluent system, may be an output of a catalytic reaction. For example, acetic acid can be an output of the partial dehydrogenation of ethanol. The catalytic reaction may comprise a dehydrogenation or a partial dehydrogenation. The catalytic reaction may comprise a partial oxidation or use a partial oxidation catalyst. The catalytic reaction may comprise a partial dehydrogenation electrolysis or a partial oxidation electrolyser. The output may be from an electrolyser or electrolyser system. The electrolyser may comprise a partial oxidation catalyst. Advantageously, the use of these systems allows the catalytic reaction to be operated in a wider range of environmental conditions, or ensures liquid storage to increase the ability of the system to store and load or unload the outputs. The measured parameter of the organic acid may be measured in a conduit, such as a pipe. For example, the conduit may be an outlet of the electrolyser system or catalytic reaction. The conduit may be a connection between the electrolyser system and a storage tank. The measured parameter of the organic acid may be measured in a storage vessel. The storage vessel may be a storage vessel for the organic acid. In some cases, the storage vessel may be a dual storage vessel capable of storing both acetic acid and ethanol. In some cases, measurement takes place in multiple locations. Multiple locations may comprise a conduit and storage vessel. Multiple locations may comprise multiple locations within a conduit or within a storage vessel. By measuring at multiple locations, the system may check the accuracy of measurements. In some cases, it may confirm that, for example, the storage vessel is sufficiently mixed to decrease the freezing point. In some cases, a mixer is used to ensure sufficient mixing of the organic acid and the diluent. The mixer may be in the storage tank, in the conduit, or as the diluent is added to the organic acid. A static or active mixer may be used. The system may comprise one or more pumps and / or valves to control the combination of the diluent with the organic acid. The one or more pumps and / or valves may form part of the mixer. A controller may control the one or more pumps or valves to control the amount or rate of diluent added to the organic acid. In some cases, a heater could be used. For example, a heater may be used to ensure the acetic acid remains liquid until it is mixed with the diluent. An external heat source may be used or heat from the system may be used. In such cases the system may be configured to consider the temperature of the organic acid, the environmental temperature and the required amount of diluent. In some cases, the presence and / or operation of a heater may also be used to help determine a required amount of diluent. The measured parameter may comprise an amount of the organic acid. The amount may be a concentration, a volume, a mass, or other suitable measurement. Where the measurement is in a storage vessel it may represent all the organic acid in the storage vessel. Where the measurement is in a conduit it may represent the additional organic acid to be added to the storage vessel. In some examples, the measurement is a measurement of the product comprising the organic acid. In some cases, the amount may be inferred from an alternative measurement. The alternative measurement may comprise a process measurement or an electronic measurement. For example, the parameter may be a reaction rate of a reaction in the catalytic reaction and / or electrolyser. For example, the parameter may be a production rate, for example of the organic acid. For example, the parameter may be a flow rate of an output of the catalytic reaction and / or electrolyser, for example a product (e.g., hydrogen) or by-product (e.g., organic acid or organic acid mixture). For example, the parameter may be a current density across the electrolyser or a catalyst of the electrolyser. In some cases, the parameter may be a flow rate of an input to the catalytic reaction and / or electrolyser, for example a LOHC such as ethanol. Using inferred measurements may reduce the number of sensors required or allow more accurate sensing or control. The most helpful measurement may be the easiest to obtain, or one already used in the system, or the most accurate, for example. In some cases, all the liquid streams (e.g. conduits) would have sensors for measuring at least one parameter of the liquid therein. This would allow the system to monitor mass flow movement for both control and safety. This may include the LOHC input, diluent and organic acid liquid streams. In one example the system determines the amount of the organic acid in a conduit connected to the storage vessel. By repeating this measurement at time intervals, the amount of organic acid in the storage vessel can be calculated without measuring the storage vessel directly. In some cases, the organic acid in the storage vessel is measured directly. In this way a single measurement within the system could be used as the basis for calculating the volume of organic acid in the of the storage tank The system may use any suitable sensor to obtain the measured parameter. For example, mass-flow sensors or volume-flow sensors may be used. In some cases, a sensor may measure a first parameter to allow an estimate of the required parameter. For example, the estimation may use a correlation between a feed rate into the electrolyser or a flow rate of hydrogen from the catalytic reaction. The system uses an environmental parameter, such as temperature, to determine the amount of diluent required to be added to the organic acid. The environmental parameter provides an indication of the actual or potential temperature of, for example, the ambient or storage vessel, so as to predict the temperature the organic acid may be exposed to or be stored at. In some cases, a temperature is used as this provides a direct indication of the organic acid temperature, and therefore the risk of freezing. The temperature may be the temperature of the organic acid (either in the conduit or in the storage vessel). This provides a direct reading of the organic acid temperature relative to freezing. The temperature may be the temperature of the storage vessel. This indicates the likely temperature the organic acid will reach within the storage vessel. The temperature may be an ambient temperature. This indicates the likely temperature the storage vessel and the organic acid will reach. In some cases, multiple temperatures or environmental parameters are used to determine a suitable amount of diluent. For example, ambient temperature and organic acid temperature may be used in combination to determine if the amount of diluent can be reduced due to the heat contained in the organic acid. In some cases, temperature measurements may be combined from different parts of the system. Considering the system as a whole, some heat may be produced, so that the temperature of the solution in either the electrolyser or the storage vessel may vary depending on the operation of the system. By measuring at multiple points this can be accounted for. In some cases, a forecast temperature may be used, or a forecast environmental parameter. Using a forecast parameter allows the system to mix a suitable amount of diluent to maintain the organic acid above freezing even if the monitoring was paused - for example when a vehicle was parked. The forecast could be for a time-period, such as one hour. Alternatively, the time-period could be between 1 minute and 60 minutes, or between 1 hour and 24 hours. In some cases, the forecast could be dependent on external factors, such as predicted operation of the catalytic reaction or electrolyser. A suitable diluent is mixable with the organic acid to reduce the freezing point of the mixture relative to the freezing point of the organic acid. However, there are advantages if the diluent is also able to easily separate from the organic acid. This is because the organic acid can then be easily purified when removed from the storage vessel or tank, and can be used in, for example, an industrial process. In some cases, the diluent is an alcohol. In some cases, the alcohol is the hydrogenized alcohol of the organic acid. This allows the input of the system to be used as both an input and a diluent, as required. In some cases, a different alcohol may be used, for example to improve separability. In some cases, multiple diluents could be used, either as a mixture or as separate additions. This could depend on, for example, the availability of each diluent. For example, the more easily separated diluent could be added preferentially or the more available diluent, or the diluent which changed the freezing point more rapidly or further. In some cases, the diluent is water. In some cases, the diluent is an output of the fuel cell, such as water. The fuel cell may be connected to the electrolyser, as described previously. In some cases, the diluent is provided independently from the fuel cell. For example, the diluent may be stored in a diluent storage vessel. The diluent storage vessel may be separate from the storage vessel, or a part of the storage vessel or attached to the storage vessel. For example, the storage vessel may be a dual use storage vessel capable of supplying the diluent and the storing the organic acid. In some cases, the diluent is separable from the organic acid by fractional freezing. In some cases, the determining the amount of diluent comprises determining a mass, or volume of diluent. In some cases, the mass or volume is configured to provide a concentration of diluent relative to the organic acid. In some cases, the amount of organic acid is monitored at a first location, while the combination with the diluent occurs at a second location. This may allow an accurate measurement of the organic acid in the first location to be combined with good mixing in the second location, for example. In some cases, this may ensure that the addition of diluent or solvent does not interfere with the accuracy of the organic acid measurement. In some cases, conduits or liquid steams will not contain the organic acid while the equipment is not running (e.g. the organic acid conduit will drain when acid is not being produced), so it may be preferable to add diluent in the storage vessel. This may be helpful if the organic acid is stored in the storage vessel for a prolonged time, as the insulation may not be sufficient to maintain the temperature above freezing point without additional diluent. In some cases, determining the amount of diluent to combine with the organic acid comprises selecting an amount of diluent to provide a target freezing point. The target freezing point may be determined based on the environmental parameter. The target freezing point may be dependent on the obtained temperature. The target freezing point may represent a minimum expected temperature within a time period (or a predetermined value lower than a minimum expected temperature). The time period may be an hour, between 1 and 60 minutes, or between 1 and 24 hours, for example. The time period may be preset. The target freezing point may be calculated by reference to stored data, such as a look-up table or algorithm. In some cases, the diluent is added continuously. The rate of addition may be controlled to reach the target freezing point. In some cases, the diluent is added intermittently. This may improve mixing of the diluent. Determining the amount of diluent to combine may comprises determining a target concentration of diluent in the storage tank and a rate of organic acid flow into the storage tank. The mixture may be removed from the storage vessel. Therefore, the system may obtain a measurement of this outflow to determine the amount of organic acid remaining. This may affect the required amount of diluent. If the storage vessel was emptied an initial amount of diluent may be added to ensure the freezing point of the initial organic acid in the storage vessel was lower. The concentration could then be lowered over time as more organic acid was added to the storage vessel. The method may be applied to a system comprising a storage vessel, a diluent source and a controller. The controller may have one or more inputs to obtain one or more measurements. In some cases, the inputs are sensors. The sensors may be part of the system or may supply measurements to the system. The system may be integrated with an electrolyser and / or a fuel cell. Measurements may be shared between these components to allow better control of the overall system. Figure 4 shows as example system 100 with an electrolyser 300 connected to a fuel cell 500. A hydrogen stream 104 is passed from the electrolyser 300 to the fuel cell 500. A feed stream 102 such as an alcohol feed stream enters the electrolyser 300 with a coproduct, the organic acid, exiting in a co-product feed stream 106. Storage infrastructure 204 includes a storage vessel 240 for storing the co-product, such as the organic acid. The co-product feed stream 106 extends between the electrolyser 300 and the storage vessel 240 and may be conveyed via a pump as illustrated (▼ e.g., a variable speed liquid pump). A diluent storage vessel 250, such as a water storage vessel, is shown connecting to the coproduct stream 106 and to the storage vessel 240 by conduits 249. In some cases the diluent storage vessel 250 is connected to only one of these or connected to either or both at one or more locations. One or more pumps may also be used here, as illustrated. A controller 241 acts as a diluent system controller. The controller 241 may be a single controller and / or may be a shared controller with other aspects of the system. The controller 241 is shown obtaining measurements from one or more sensors (♦-), such as one or more temperature sensors, disposed at various locations within the system. The controller 241 may obtain measurement from the diluent storage vessel 250, the electrolyser 300, the storage vessel 240 and the fuel cell 500, as shown. In some cases, multiple measurements may be obtained, or some measurements may not be used or required. The controller 241 is also shown obtaining measurements from liquid feed streams 106, 249. The controller 241 may also receive measurements externally, for example by wireless or wired communication methods or from external sensors. Temperature measurements may be received in some examples. An ambient temperature measurement 248 may be obtained from a temperature sensor as shown. Forecast environmental conditions 247, such as temperature and / or weather may also be obtained by the controller. Thus the controller can monitor the status of the system, in particular a concentration of the organic acid in the storage vessel 240 and, based on the environmental conditions introduce an amount of diluent to reduce the freezing point of the organic acid so that the organic acid remains liquid in the storage vessel. The controller may use one or more of the shown sensors to determine, or improve the determination, of the amount of diluent. In one example a set amount of diluent is added per amount of organic acid. In an alternative example the amount of diluent is varied, for example based on the current or predicted low temperature. In this example the amount of diluent used is reduced, limiting the amount needing to be separated from the organic acid in a later process. Figure 5 shows an adapted system 100 from the system of Figure 4. The electrolyser 300, fuel cell 500 and storage vessel 240 are equivalent. However, the water as diluent is now supplied from an output stream 246 of the fuel cell 500. This makes use of a waste produce of the fuel cell 500 to dilute the organic acid. The applicability of this process may depend on the water (or other diluent) production of a fuel cell (or other secondary reaction. In some cases a water storage vessel may still be used, with the water from the fuel cell 240 first feeding into the water storage vessel before being combined with the organic acid. This may ensure a minimum level of water is present. Consider an example where adding water as a diluent (or solvent) to the acid product would widen the temperature window within which this product stream remains as a liquid (so does not solidify). The temperature of the acid product can be monitored in both the acid handling infrastructure and the acid storage vessel. The dilution of the acid product can be undertaken in a temperature dependent manner by controlling the flow of water into the acid stream either within the acid handling infrastructure or within the storage vessel. Control over the amount of water added to the acid product / organic acid, to achieve a target freeze point, is achieved by controlling liquid flow rates from the water source (e.g., from the storage tank or from the fuel cell) to the blend points within the acid handling infrastructure or the acid storage vessel. Blend points may comprise one or more valves, controllers, or switches. Identifying an appropriate freeze point threshold may be achieved by combining data from temperature measurements within each area of the system and from the environment around the system with predictive information of the ambient temperature forecast for the near term future in the location of the integrated system. The controller can control water flow rates based on this data, or a reduced sensor set may be used. Figure 6 shows a further example system. In this case the diluent is not water but the feed product to the electrolyser 300. For example the feed product may be an alcohol which is easier than water to remove from the organic acid once mixed. Diluents other than water and / or alcohol may be used. A diluent should be selected to lower the freezing point of the co-product (organic acid) while being separable in post processing steps. The feed stream 102 now has a valve or control to allow at least a portion 102a of the alcohol to be diverted to the co-product stream 106 or to the storage vessel 240. The controller 241 is now shown with sensors to, or obtaining measurements from, the feed stream to sense and / or control the amount of alcohol added to the organic acid. The same process described with respect to water may be used with respect to alcohol, but with the illustrated changes in sensor location and system connections. In some cases the system may use multiple diluents. For example both water and the input feed stream could be used. The selection of diluent may be based on the amount of feed or water available, or one could be used as a back-up, for example. In some examples a consistent understanding of the volume of organic acid in either the production handling system (i.e. the electrolyser or conduits) or storage vessel is used to accurately determine diluent. For example this may form an input to the controller to determine what volume of diluent (or solvent) is required to be blended with the organic acid stream to achieve a desired lower freezing point for the resultant acid / diluent mixture. A mass flow meter could enable an accurate understanding of the volume of organic acid. An understanding of the temperature of the organic acid-containing liquid in either the production handling system or storage equipment / vessel may also provide an input to a controller. The controller may, based on this temperature, determine if diluent needs to be added to the organic acid containing liquid in order to reduce the freezing point to maintain the organic acid in a liquid state. A temperature probe or sensor may be used to obtain the temperature. The diluent storage vessel should be sized to enable an appropriate volume of diluent to be stored in anticipation of the volume of organic acid product. The various illustrative logical blocks, controllers, modules, circuits, elements, and / or components described in connection with the examples disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic component, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A controller may be a general-purpose processor, which may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, circuit, and / or state machine. A processor may also be implemented as a combination of computing components, e.g., a combination of a DSP and a microprocessor, a number of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executable by a processor, or in a combination of both, in the form of processing unit, programming instructions, or other directions, and may be contained in a single device or distributed 5 across multiple devices. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral 10 to the processor. To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. 15           This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be 20 incorporated herein as if individually set forth.

Claims

1. A method of storing a product comprising an organic acid output from a catalytic reaction, the method comprising the steps of:obtaining a measurement of a parameter of the product;obtaining an environmental parameter;determining an amount of a diluent to combine with product, and combining the diluent with the product to provide a mixture,wherein the amount of the diluent is determined based on the measurement of the product and the obtained environmental parameter to substantially maintain the mixture in a fluid or flowable condition.

2. A method of storing a product comprising an organic acid output from a catalytic reaction, the method comprising the steps of:obtaining a measurement of a parameter of the product;obtaining an environmental parameter;determining an amount of a diluent to combine with the product based on the measurement of the product and the obtained environmental parameter to provide a mixture having a target freezing point; andcombining the diluent with the product comprising the organic acid to provide the mixture having the target freezing point.

3. The method of claim 1 or 2 further comprising producing the organic acid by performing the catalytic reaction.

4. The method of any one of claims 1 comprises dehydrogenation. to 3, wherein the catalytic reaction 5. The method of any one of claims 1 to 3, wherein the catalytic reaction comprises partial dehydrogenation.

6. The method of any one of claims 1 to 3, wherein the catalytic reaction comprises a partial oxidation catalyst.

7. The method of any one of claims 1 to 3, wherein the catalytic reactioncomprises partial dehydrogenation electrolysis.

8. The method of any one of claims 1 to 3, wherein the catalytic reaction comprises a partial oxidation electrolyser.

9. The method of any one of claims 1 to 8, wherein the output is from an electrolyser.

10. The method of claim 9, wherein the electrolyser comprises a partial oxidation catalyst.

11. The method of any one of claims 1 to 10, wherein the parameter of the product comprises an amount of product or organic acid in a conduit to a storage vessel.

12. The method of any one of claims 1 to 10, wherein the parameter of the product comprises an amount of product or organic acid in a or the storage vessel.

13. The method of claims 11 or 12, wherein the amount is a volume.

14. The method of any one of claims 1 to 13, wherein combining the diluent with the product comprises mixing the diluent and product.

15. The method of claim 14, wherein the mixing uses a mixer, optionally wherein the mixing occurs on entry of the product and / or diluent into the storage vessel.

16. The method of any one of claims 1 to 15, wherein combining the diluent with the product is controlled by one or more variable speed pumps and / or valves.

17. The method of any one of claims 1 to 16, wherein the parameter of the product comprises a reaction rate of the catalytic reaction, optionally a reaction rate in the electrolyser.

18. The method of any one of claims 1 to 17, wherein the parameter comprises a flow rate of at least one output of the catalytic reaction, optionally from the electrolyser.

19. The method of claim 18, wherein the parameter comprises a mass flow rate.

20. The method of claim 18 or claim 19, wherein the output is the organic acid output.

21. The method of any one of claims 1 to 20, wherein the parameter of the product comprises a flow rate of an input to catalytic reaction, optionally an input to the electrolyser.

22. The method of any one of claims 18 to 21, wherein the at least one output is a hydrogen output.

23. The method of any one of claims 1 to 22, wherein obtaining a measurement comprises obtaining a measured value from at least one sensor.

24. The method of claim 23, wherein the at least one sensor comprises a massflow sensor.

25. The method of claim 23 or claim 24, wherein the at least one sensor comprises a volume-flow sensor.

26. The method of any one of claims 1 to 25, wherein the measurement comprises an estimation.

27. The method of claim 26, wherein the estimation comprises one or more of: a correlation with a feed rate into the catalytic reaction, optionally into the electrolyser,an electrical measurement, for example a current, used in the catalytic reaction, optionally the electrolyser, anda flow rate of hydrogen from the catalytic reaction, optionally from the electrolyser, optionally from the catalyst.

28. The method of any one of claims 1 to 27, wherein the environmental parameter comprises a temperature.

29. The method of claim 28, wherein the temperature comprises a temperature of the product.

30. The method of claim 28 or claim 29, wherein the temperature comprises a temperature of a or the storage vessel.

31. The method of any one of claims 28 to 30, wherein the temperature comprises an ambient temperature.

32. The method of any one of claims 28 to 31, wherein the temperature comprises a forecast temperature.

33. The method of any one of claims 1 to 32, comprising the step of obtaining a weather forecast.

34. The method of any one of claims 1 to 33, wherein the diluent comprises an alcohol.

35. The method of claim 34, wherein the alcohol is a hydrogenized alcohol of the organic acid.

36. The method of claim 34, wherein the alcohol is an input for the catalytic reaction, such that the alcohol is used as both a reactant and a diluent.

37. The method of any one of claims 1 to 36, wherein determining the amount of diluent comprises determining a percentage of diluent relative to organic acid.

38. The method of any one of claims 1 to 37, wherein the diluent is selected for separability from the organic acid.

39. The method of any one of claims 1 to 38, wherein combining the diluent with the product comprises introducing diluent from a diluent storage vessel.

40. The method of claim 39, wherein the diluent storage vessel is an alcohol storage vessel also configured to supply the catalytic reaction, optionally the electrolyser.

41. The method of claim 39 or 40, wherein the diluent storage vessel is a water storage vessel.

42. The method of any one of claims 1 to 41, wherein combining the diluent with the product comprises introducing diluent from an output of a fuel cell.

43. The method of claim 42, wherein an input of the fuel cell is connected to an output of the catalytic reaction, optionally a or the electrolyser.

44. The method of claim 43, wherein the fuel cell comprises a hydrogen fuel cell.

45. The method of any one of claims 1 to 44, wherein the parameter of the product comprises an amount of the organic acid in a conduit connected to the storage vessel.

46. The method of any one of claims 1 to 45, comprising the step of calculating the amount of organic acid in the storage vessel based on the measurement in the conduit.

47. The method of any one of claims 1 to 46, wherein the parameter of the product comprises an amount of the organic acid in a or the storage vessel.

48. The method of any one of claims 1 to 47, wherein the parameter of the product comprises one or more of an amount or a concentration of the organic acid.

49. The method of any one of claims 1 to 48, wherein the parameter of the product comprises a production rate of organic acid.

50. The method of any one of claims 1 to 49, wherein the parameter of the product comprises a flow rate of an input into the catalytic reaction, optionally the electrolyser, or an output from the catalytic reaction, optionally the electrolyser.

51. The method of any one of claims 1 to 50, wherein the parameter of the product comprises a current density across the electrolyser and / or a catalyst of the electrolyser.

52. The method of any one of claims 1 to 50, wherein the parameter of the product comprises a concentration of the organic acid in the storage vessel.

53. The method of any one of claims 1 to 52, comprising the step of obtaining the measurement of the parameter of the product at a first location; and combining the diluent and product at a second location, the second location downstream of the first location.

54. The method of any one of claims 1 to 53 wherein determining the amount of diluent to combine comprises selecting an amount of diluent to provide a target freezing point, or to lower the freezing point of the organic acid to or below a target temperature.

55. The method of claim 54, wherein the target freezing point is dependent (preferably determined based) on the obtained environmental parameter, preferably temperature.

56. The method of any one of claims 1 to 55, wherein the target freezing point represents a minimum expected temperature within a time period.

57. The method of claim 56, wherein the time period is preset.

58. The method of any one of claims 1 to 57, wherein determining the amount of diluent to combine with the product comprises determining aconcentration of diluent in the storage tank and a rate of product flow into the storage tank.

59. The method of any one of claims 1 to 58, comprising the step of obtaining a measurement of an outflow from the storage vessel.

60. The method of any one of claims 1 to 59, comprising the step of obtaining a measurement of the volume of diluent and organic acid within the storage vessel.

61. A system for storing a product comprising an organic acid output from a catalytic reaction, the system comprising:a storage vessel configured to store the product;a diluent source configured to provide a diluent to combine with the product;a controller configured to:obtain a measurement of the product;obtain an environmental parameter;determine an amount of the diluent to combine with the product based on the measurement of the product and the obtained environmental parameter to provide a mixture having a target freezing point; andcontrol the diluent from the diluent source into the storage vessel according to the determined amount to provide the mixture having the target freezing point.

62. A controller configured to control the freezing point of a product comprising an organic acid, wherein the organic acid is an output of a catalytic reaction, the controller configured to:obtain a measurement of the product;obtain an environmental parameter;determine an amount of a diluent to combine with the organic acid based on the measurement of the product and the obtained environmental parameter; andcontrol the diluent from the diluent source into the storage vessel according to the determined amount.

63. A system comprising:an electrolyser configured to produce a product comprising an organic acid output via a catalytic reaction,a fuel cell,a product storage tank configured to store the product comprising the organic acid output from the electrolyser,a diluent storage tank;wherein the diluent storage tank is fluidly connected to the product storage tank to allow the organic acid to be diluted to control the freezing point of the product.

64. A method of storing a product comprising an organic acid output from a catalytic reaction, the method comprising the steps of:obtaining a measurement of a parameter of the organic acid;obtaining a temperature, such as: a temperature of the organic acid, an ambient temperature, a forecast temperature, and / or a temperature of a storage vessel;determining an amount of a diluent to combine with the organic acid, including determining a target freezing point based on the obtained temperature and selecting an amount of diluent to combine with the organic acid based on the obtained measurement of the parameter of the organic acid to provide the target freezing point, andcombining the diluent with the organic acid according to the determined amount, thereby mitigating freezing of the product.

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