Electrochemical process for simultaneous conversion of co 2 and ch 4 into storable fuel and systems thereof

Abstract

The present application relates to greenhouses gases (GHGs) mitigation. More specifically, the present application relates to an electrochemical process and systems for simultaneous conversion of CO2 and CH4 from a flue gas, optionally further comprising N2O and / or CO. The present application includes an electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient under predetermined electrochemical conditions to at least partially convert CO2 and CH4 into methanol; and recovering the produced methanol. Also provided is an electrochemical system for conducting the process.

Description

ELECTROCHEMICAL PROCESS FOR SIMULTANEOUS CONVERSION OF CO2 AND CH4INTO STORABLE FUEL AND SYSTEMS THEREOFCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims the benefit of priority of co-pending U.S. Provisional Patent Application No. 63 / 609,743, which was filed December 13, 2023, the content of which is incorporated herein by reference in its entirety.FIELD

[0002] The present application is in the field of greenhouse gases (GHG) management. More specifically, the present application relates to an electrochemical process and systems for simultaneous conversion of CO2 and CH4.BACKGROUND

[0003] The rapid increase of greenhouse gases (GHG) in the atmosphere is driven by growing population, human activities and expanding industries including agriculture (Feng et al., 2022). Correspondingly, an increase of GHG emissions generates several impacts on human health and environment through the global warming and climate change. According to the Intergovernmental Panel on Climate Change (IPCC) report, the atmospheric concentrations of CO2 and CH4 are by 147% and 259% higher than the preindustrial level (around 1750) (IPCC, 2021 ). Based on the report of the United Nations Climate Change Conference (COP26, 2021 ), the rise in the global average temperature might reach 2.4 °C by the end of this century; then, the efforts should be done to limit it to 1.5 °C (The United Nations Framework Convention on Climate Change - UNFCCC, 2021 ). In this light, Canada committed to decrease the methane generation by 30% until 2030 (Environment Climate Change Canada - ECCC, 2021 ). Since 2015, Canada is on a path to reducing GHG emissions following the Pan-Canadian Framework to control Climate Change. After Canada's commitments in COP26, the Canadian Net-Zero Emissions was implemented as an enactment. Prior to these efforts, Canada's emissions were on a steady upward climb and were projected to increase by 12% between 2005 and 2030, while in 2020, total Canada’s GHG emissions were 672 Mt CO2 eq (FIG.1 ) (ECCC, 2021 ). During COP28 (2023), more than 150 countries signed on the Global Methane Pledge which has agoal to cutting methane emissions by 30% worldwide by 2023 compared to 2020 levels. Canadian government introduced new methane rules for oil and gas industry (Canadian Broadcasting Corporation - CBC, 2023).

[0004] Among all Canadian sectors, the emission of GHG by Agriculture and Waste, occupy 10% (69 Mt CO2 eq) and 7.4%, respectively (FIG.2) (ECCC, 2021 ). A significant contributor within the agriculture sector is non-energy GHG emissions related to the production of crops and livestock. In 2020, agriculture sector accounted for 30% of national CH4 emissions, while the main driver of such emission is livestock digestion (enteric fermentation), around 43% of total agricultural emissions (ECCC, 2021 ).

[0005] Environmental engineering treatment facilities (e.g., wastewater treatment plants, landfill) are also among the major GHG contributor beside building ventilation systems, agriculture, and other industries (Ashrafi, 2012; Kampschreur et al., 2009), where oil and gas, construction, as well as transportation play significant role (see FIG.2).

[0006] Therefore, tackling the methane emissions from all potential sources including sanitary facilities, as well as livestock production, is necessary but also challenging. For example, with a population growth, the need for food is constantly increasing; therefore, a rise of the GHG production from agriculture sector is inevitable. Accordingly, cattle farms are considered one of the most important food production entities. In 2023 in Quebec, about 3180 farms (one million cattle) were dedicated to cattle breeding (Stat. Can. 2023, Gov. Quebec, 2023). Considering that each ruminant livestock can produce about 60 to 130 kg of methane annually (Johnson et al., 1995), thus, they can significantly contribute to 76 Mt CO2 eq produced annually by Quebec province (ECCC 2020).

[0007] Biological environmental engineering technologies also emit methane accompanied with carbon dioxide (biogas) in various ratios (Snip, 2010), which might reach 7.4% (50 Mt CO2 eq.) in Canada (ECCC 2020). The common biogas generation source are wastewater treatment plants (WWTPs) (Snip, 2010). For example, the initial analysis of biogas in pilot facilities in a small size WWTP in Quebec province, duringfall 2021 was revealed a ratio of CO2:CH4 = 60:24% vol at 18°C and CO2:CH4 = 64:17% vol at 13°C (Abedini 2022).

[0008] Considering the necessity of depletion of global warming, a sustainable generation of energy is a big challenge for the scientific and industrial communities (Ashrafi 2012). Subsequently, the conversion of CO2 and CH4 into fuel is an alternative option to GHG sequestration in order to fight the global warming problem.

[0009] Furthermore, wastewater treatment plants beside other anthropogenic emission resources (e.g., fossil fuel production and consumption) play a significant role in GHG emission into the atmosphere and increasing global warming (Feng et al., 2022; Kampschreur et al., 2009). From April 2018, the Government of Canada committed $200 million deploy emerging renewable energy technologies to reduce GHGs emission (Pham, 2020). Canada committed $30M to establish Methane Centre of Excellence focusing on methane emission and introduced a cap (CBC, 2023). Canada pledged methane emission reduction plan for the oil and gas sector to achieve a cut of at least 75% below 2012 levels (CBC, 2023).

[0010] Wastewater treatment plants (WWTPs) are recognized as one of the important sources of GHG emissions in the world since they produce CO2, CH4, and N2O during biological processes. A large value of CO2 occurs during aerobic processes which would be represented by Eq. 1 (Czepiel et al., 1993):C6H12O6 + 6O2 6CO2 + 6H2O (1 )

[0011] N2O is another GHG that produce in biological process via nitrification and denitrification (Eqs. 2 and 3) due to the accumulation of nitrite during the denitrification process. N2O production is summarized in Eq. 4 (Bahini et al., 2009; Snip, 2010).NH4++ 2O2 NO3- + H2O + 2H+Nitrification (2)NO3- + H++ 0.625 CH3COOH 0.5 N2 + 1 .25 CO2 + 1 .75 H2O Denitrification (3)NO3-^ NO2-^ NO -^N2O (4)

[0012] Methane is the main greenhouse gas produced in anaerobic digestion in WWTP via methanogenesis. The following reactions (Eqs. 5 and 6) show the methanogenic stage of anaerobic processes (Snip, 2010).CHsCOOH CH4 + CO2 (5)2CH3CH2OH 3CH4 + CO2 (6)

[0013] As such, there is need to provide improved methods for reducing GHG emission and capture emitted carbon in order to convert it into green fuel for sustainable energy storage.SUMMARY

[0014] It has been shown herein that processes of the present application provide for the simultaneous conversion of CO2 and CH4 into storable fuels. The processes of the present application further provide for removal of GHGs from a gas flow, without the need for separation, by simultaneous conversion of CO2 and CH4 in an ambient environment into a fuel independently of gas concentration ratio. Comparable processes did not display the same properties, or configurations highlighting the advantageous results obtained with the processes of the application.

[0015] Accordingly, the present application includes an electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert CO2 and CH4 into methanol; and recovering the produced methanol; wherein the flue gas is injected at a ratio of a volume of the gas flow proportional to a volume of the electrochemical cell of about 400 to about 2500 over a one hour period; wherein the electrochemical conditions comprise a temperature of about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

[0016] The present application includes an electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert CO2 and CH4 into methanol; and recovering the produced methanol; wherein the electrochemical conditions comprise a temperature of about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

[0017] The present application further includes an electrochemical system for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the system comprising: an electrochemical cell configured to contain an electrolyte, and comprising: a metallic anode and a metallic cathode configured for being in contact with the electrolyte and for being electrically connected to a power source configured to apply a voltage gradient between the metallic anode and the metallic cathode; a gas inlet configured for injecting flue gas in the electrochemical cell; an electrolyte inlet configured to supply the electrolyte; a product outlet configured for recovering the electrochemical products; and a gas discharge outlet configured to discharge gas produced in the electrochemical system.

[0018] Further included is the use of the electrochemical process or the electrochemical system of the present application, for producing storable fuel comprising methanol, for reducing greenhouse gases in a flue gas, and / or for mitigating greenhouse gases emissions.

[0019] Other features and advantages of the present application will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating embodimentsof the application, are given by way of illustration only and the scope of the claims should not be limited by these embodiments, but should be given the broadest interpretation consistent with the description as a whole.BRIEF DESCRIPTION OF DRAWINGS

[0020] The embodiments of the application will now be described in greater detail with reference to the attached drawings in which:

[0021] FIG.1 shows a graph of total greenhouse gases emissions in Canada, by province, in 2021 according to prior art.

[0022] FIG.2 shows a graph of total greenhouse gases emissions in Canada, by sector, in 2021 according to prior art.

[0023] FIG.3 shows a schematic representation of an exemplary electrochemical system for CO2 and CH4 sequestration and its conversion to electrical power in a cattle farm, according to embodiments of the present application.

[0024] FIG.4 shows an image of an exemplary electrochemical system according to embodiments of the present application.

[0025] FIG.5 shows a graph of the influence of electrical potential on the methanol production from synthetic and natural biogas in an exemplary electrochemical system at a flowrate of 1 -1.5 m3 / h, input duration of 30 minutes and ambient temperature, according to embodiments of the present application.

[0026] FIG.6 shows a graph of the influence of the gas input duration on methanol production from synthetic, and natural biogas in an exemplary electrochemical system at a flowrate of 1 -1 .5 m3 / h, potential of 80-80.8 V and ambient temperature, according to embodiments of the present application.

[0027] FIG.7 shows a graph of the influence of temperature on the methanol production from synthetic and natural biogas in an exemplary electrochemical system at a potential of 80.5-80.8 V, input duration of 30 minutes and flowrate of 1 -1.5 m3 / h, according to embodiments of the present application.

[0028] FIG.8 shows a graph of the influence of synthetic and natural biogas flowrate on the methanol production in an exemplary electrochemical system at apotential of 80.6 V, input duration of 30 minutes and ambient temperature, according to embodiments of the present application.

[0029] FIG.9 shows an ion chromatograph of anions in an effluent, according to embodiments of the present application.

[0030] FIG.10 shows an ion chromatograph of cations in an effluent, according to embodiments of the present application.

[0031] FIG.11 shows a graph of the influence of biogas input duration on anions of effluent in an exemplary electrochemical system at a flowrate of 1 m3 / h, ambient temperature, and potential of 80V, according to embodiments of the present application.

[0032] FIG.12 shows a graph of the influence of biogas input duration on cations of effluent in an exemplary electrochemical system at a flowrate of 1 m3 / h, ambient temperature, and potential of 80V, according to embodiments of the present application.

[0033] FIG.13 shows a graph of the influence of voltage on methanol production in an exemplary electrochemical system at a flowrate of 0.8-1.3 m3 / h, temperature of 15.5-25°C, input duration of 15-30 minutes and potential of 80-90V, according to embodiments of the present application.

[0034] FIG.14 shows a graph of the influence of input duration on methanol production in an exemplary electrochemical system at a flowrate of 0.8-1 .3 m3 / h, temperature of 15.5-25°C, input duration of 15-30 minutes and potential of 80-90V, according to embodiments of the present application.

[0035] FIG.15 shows a schematic representation of an electrochemical modular device for various GHG flowrates, according to embodiments of the present application.

[0036] FIG.16 shows a schematic model of an electrochemical device for high GHG flowrate, according to embodiments of the present application.DETAILED DESCRIPTIONI. Definitions

[0037] Unless otherwise indicated, the definitions and embodiments described in this and other sections are intended to be applicable to all embodiments and aspects of the present application herein described for which they are suitable as would be understood by a person skilled in the art.

[0038] As used in this application and claim(s), the words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "include" and "includes") or "containing" (and any form of containing, such as "contain" and "contains"), are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0039] The term “consisting” and its derivatives as used herein are intended to be closed terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, and also exclude the presence of other unstated features, elements, components, groups, integers and / or steps.

[0040] The term “consisting essentially of’, as used herein, is intended to specify the presence of the stated features, elements, components, groups, integers, and / or steps as well as those that do not materially affect the basic and novel characteristic(s) of these features, elements, components, groups, integers, and / or steps.

[0041] The terms "about", “substantially” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies or unless the context suggests otherwise to a person skilled in the art.

[0042] As used in the present application, the singular forms “a”, “an” and “the” include plural references unless the content clearly dictates otherwise. For example, an embodiment including “a compound” should be understood to present certain aspects with one compound, or two or more additional compounds.

[0043] In embodiments comprising an “additional” or “second” component, such as an additional or second component, the second component as used herein is chemically different from the other components or first component. A “third” component is different from the other, first, and second components, and further enumerated or “additional” components are similarly different.

[0044] The term “and / or” as used herein means that the listed items are present, or used, individually or in combination. In effect, this term means that “at least one of” or “one or more” of the listed items is used or present.

[0045] The term “suitable” as used herein means that the selection of the particular components or conditions would depend on the specific steps to be performed, the identity of the components to be transformed and / or the specific use for the components, but the selection would be well within the skill of a person trained in the art.

[0046] The term “GHG” as used herein refers to greenhouse gases.

[0047] The term “WWTP” as used herein refers to wastewater treatment plants.

[0048] The term “GO” as used herein refers to gas chromatography.

[0049] The term “IC” as used herein refers to ion chromatography.

[0050] The term “DC” as used herein refers to direct current.

[0051] The term “UV” as used herein refers to ultraviolet.

[0052] The term “TCD” as used herein refers to thermal conductivity detector.

[0053] The term “ECD” as used herein refers to electron capture detector.

[0054] The term “FID” as used herein refers to flame ionization detector.II. Processes of the Application

[0055] It has been shown herein that processes of the present application provide for the simultaneous conversion of CO2 and CPU into storable fuels. The processes of the present application further provide for removal of GHGs from a gas flow, without the need for separation, by conversion of CO2 and CPU into a fuel independently of gas concentration ratio. Comparable processes did not display thesame properties, highlighting the advantageous results obtained with the processes of the application.

[0056] Therefore, electrochemical conversion of CO2 and CH4 to methanol according to the present application is much more economical and energy-efficient than GHG capturing only (Abedini 2022, Arnarson et al. 2018; Hazarika et al. 2019; He et al. 2016; Ma et al. 2017).

[0057] Accordingly, the present application includes an electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to convert CO2 and CH4 at least partially into methanol, and recovering the produced methanol; wherein the electrochemical conditions comprise a temperature of about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

[0058] The present application further includes an electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to convert CO2 and CH4 at least partially into methanol, and recovering the produced methanol; wherein the flue gas is injected, at a ratio of volume of the gas flow proportional to a volume of the electrochemical cell of about 400 to about 2500 over a one hour period, wherein the electrochemical conditions comprise a temperature of about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

[0059] The present application also includes an electrochemical process for treating at least one of CO, CO2 and CH4, the process comprising: injecting at least one of CO, CO2 and CH4 into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert at least one of CO, CO2 and CH4 into methanol; and recovering the produced methanol; wherein the electrochemical conditions comprise a temperature of gas about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

[0060] The present application further includes an electrochemical process for treating at least one of CO, CO2 and CH4, the process comprising: injecting at least one of CO, CO2 and CH4 into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert at least one of CO, CO2 and CH4 into methanol; and recovering the produced methanol; wherein the at least one of CO, CO2 and CH4 is injected at a ratio of volume of the gas flow to a volume of the electrochemical cell of about 400 to about 2500 over a one hour period, wherein the electrochemical conditions comprise a temperature of gas about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

[0061] The present application further includes an electrochemical process for at least partially removing at least one of CO, CO2 and CH4 from a gas, the process comprising: injecting the gas into an electrochemical cell comprising electrodes and an electrolyte;applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert at least one of CO, CO2 and CH4 into methanol; and recovering the produced methanol; wherein the gas is injected at a ratio of volume of the gas flow proportional to a volume of the electrochemical cell of about 400 to about 2500 over a one hour period, wherein the electrochemical conditions comprise a temperature of gas about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes

[0062] In some embodiments, the flue gas further contains N2O which is at least partially converted to nitrogen derivatives comprising nitrogen gas, nitrates or mixtures thereof. In some embodiments, the flue gas further contains CO which is at least partially converted to methanol. In some embodiments, the flue gas is not subjected to separation prior to injection into the electrochemical cell, such that CO2 and CH4, or CO2, CH4 and N2O and / or CO are simultaneously converted from the mixture in the flue gas. As such, the process of the application can be applied to all types of activities, but not limited to, generating GHGs such as refineries, transportation, buildings, wastewater treatment plants, landfills, food production industry, or agriculture industry including cattle farms.

[0063] In some embodiments, a given flue gas may contain various other gases and / or impurities, such as NH3, H2S, etc. A skilled person in the art will thus appreciate that other byproducts may be produced depending on the initial composition of the flue gas. The electrolyte composition may also have an influence on byproducts. For example, when effluents from WWTP are used, struvite and fungicide (cupper hydroxide) may be generated. As such, other byproducts of value may be produced and isolated if desired and this would be within the purview of the skilled person.

[0064] In some embodiments, the electrochemical system and process of the present application convert simultaneously CO2 and CH4 to storable energy and subsequently to electrical power (FIG.3). It can capture CO2 and CPU and optionally COfrom flue gas and at least partially convert to methanol, which can generate electrical energy directly from GHGs at the source of emission, e.g. by-products of industrial production or biological processes (agricultural sector, WWTP, landfill, etc.). The system may be exposed to continuous flow of emitted GHGs, where chemical reactions under low direct current voltage convert simultaneously gases to a storable fuel (e.g., methanol). Theoretically, the following reactions (Eq. 7-9) permit to oxidize CH4 and optionally CO, and reduce CO2 to methanol:CH4 + H2O CO + 3H2 (7)CO + 2H2^ CH3OH (8)CO2 + 3H2CH3OH + H2O (9)

[0065] Additionally, one of the main goals of wastewater treatment plants is to remove organic matter and nutrients such as nitrogen and phosphorus. Ammonia, nitrites, nitrates, polyphosphate, and orthophosphates are the major nutrients’ compounds in wastewater which increase the excessive growth of algae and aquatic plants when present in the WWTP effluent. Therefore, the removal of nitrogen and phosphorus from wastewater before it is discharged into the environment is also of great importance for various environmental and public health reasons. Otherwise, eutrophication might cause a depletion of oxygen levels in the surface water and subsequent overgrowth of toxic algae (Ozgur et al., 2023).

[0066] As such, in some embodiments, the electrolyte of the process of the present application is wastewater, gray water, effluent water, tap water or mixtures thereof. In some embodiments, the electrolyte comprises at least one of phosphates, nitrates, sulphates and ammonium. In some embodiments, the electrolyte does not require the addition of a catalyst. In some embodiments, phosphates, nitrates, sulphates and ammonium will be converted as follows:Removal of sulphateRemoval of nitrate and nitriteNO3- + H2O + 2e- NO2- + 2OH-N02- + 2H2O + 3e" 72 N2 + 40H-NO3- + 3H2O + 5e- % N2+ 60H-Removal of ammonium and phosphorusMg2++ NH4++ H2PO4“ + 6H2O MgNH4PO4'6H2O (struvite) + 2H+As such, struvite is produced which may be used as a fertilizer and copper sulphate may be converted to copper hydroxide to be used as a biocide.

[0067] In some embodiments, a voltage applied is from about 75V to about 95V. In some embodiments, a voltage applied is from about 78V to about 91V. In some embodiments, a voltage applied is about 80V.

[0068] In some embodiments, the voltage gradient is from about 1 V / cm to about 12V / cm. In some embodiments, the voltage gradient is from about 6V / cm to about 10V / cm.

[0069] In some embodiments, the flue gas is injected at a ratio of volume of the gas flow proportional to a volume of the electrochemical cell of about 500 to about 1200 over a one hour period. In some embodiments, the flue gas is injected at a ratio of volume of the gas flow proportional to a volume of the electrochemical cell of about 600 to about 1100 over a one hour period. A skilled person in the art will appreciate that the injection ratio of volume of the gas flow to a volume of the electrochemical cell may vary depending on the nature of a modular unit, for example comprising a plurality of electrochemical cells, and the present application is not to be limited thereto. Overall, one may consider that there would be no gas flow limitation, expect dictated by the limit that the apparatus can withstand.

[0070] In some embodiments, the temperature is provided by the temperature of the flue gas being injected. In some embodiments, the electrochemical cell is not heated by an external heating means. In some embodiments, the electrochemical conditions comprise a temperature of about 10 °C to about 30 °C. In some embodiments, the electrochemical conditions comprise a temperature of about 15 °C to about 25 °C.

[0071] In some embodiments, the process is conducted under continuous gas flow for about 10 minutes to about 60 minutes. In some embodiments, the process is conducted under continuous gas flow for about 15 minutes to about 30 minutes.

[0072] In some embodiments, the CO2 and CH4 are further partially converted into formic acid and / or formates. In some embodiments, the CO2 and CH4 are further partially converted into formic acid and / or formates according to the following equations:CH4 + 2H2O CO2 + 8H++ 8e-CO2 + 2H++2e ^ HCOOH

[0073] It will be appreciated that the various electrochemical conditions may be varied to arrive at different ratios of produced methanol and formic acid / formates depending on needs, and this would be within the purview of a skilled person in the art. As mentioned above, other byproducts may also be obtained depending on the flue gas composition and nature of the electrolyte, etc.

[0074] In some embodiments, the process further comprises, after the process is conducted under continuous flow, replacing the electrolyte and repeating injecting, applying and recovering. In some embodiments, the process works as a sequential batch process with respect to a systematic discharge of electrolyte containing converted methanol, and optionally other reaction products. In some embodiments, the electrolyte is supplied in the form of droplets (shower-like) or mist in a continuous or non-continuous manner.

[0075] The present application also provides use of the process of the present application, for producing storable fuel comprising methanol, for reducing greenhouse gases in a flue gas and / or for mitigating greenhouse gases emissions.III. Devices and Uses of the Application

[0076] The present application also includes an electrochemical system for converting CO2 and CH4 contained in a flue gas into methanol, the system comprising: an electrochemical cell configured to contain an electrolyte, and comprising:a metallic anode and a metallic cathode configured for being in contact with the electrolyte and for being electrically connected to a power source configured to apply a voltage to generate a potential gradient between the metallic anode and the metallic cathode; a gas inlet configured for injecting flue gas in the electrochemical cell; an electrolyte inlet configured to supply the electrolyte; a product outlet configured for recovering the electrochemical products; and a gas discharge outlet configured to discharge gas produced in the electrochemical system.

[0077] In some embodiments, the metallic anode is a copper anode. In some embodiments, the metallic cathode is a lead cathode. As such, the system uses affordable metallic materials for the electrodes, without the necessity to rise temperature for efficient electrochemical reactions. In some embodiments, the distance between the anode and the cathode is about 0.5 cm to about 80 cm. In some embodiments, the distance between the anode and the cathode is about 1 cm to about 40 cm. In some embodiments, the distance between the anode and the cathode is about 5 cm to about 20 cm.

[0078] An exemplary electrochemical system is shown in FIG.4, where the electrochemical system 10 has an electrochemical cell 20 containing the electrodes and electrolyte (not shown), the electrodes being configured to electrically connected to a power source (not shown). The Figure shows a gas inlet 30 configured for injecting flue gas in the electrochemical cell 20, a product outlet 40 configured for recovering the electrochemical products, and a gas discharge outlet 50 configured to discharge gas produced in the electrochemical system. An electrolyte inlet 60 is also provided on the electrochemical cell configured to supply the electrolyte, allowing a continuous supply of new / fresh electrolyte in a sequential manner without the need to open the cell after each treatment.

[0079] FIG.15 shows a schematic representation of an exemplary electrochemical modular device for various GHG flowrates. The module 150 shown consists of eight (8) cells 20 of volume of 800 L, with electrical connections 152, gasinlets 30 configured for injecting flue gas in each cell 20, a product outlet 40 configured for recovering the electrochemical products, an electrolyte inlet 60 and a gas discharge outlet 50 configured to discharge gas produced in the electrochemical system.

[0080] Another exemplary electrochemical system 20 is also shown in FIG.16, where a small model of 12L is presented, in which electrolyte is supplied through inlet 60 in the form of shower before being exposed to electrical field and high flue gas flowrate. FIG.16 also shows the two electrodes 70, gas inlet 30, product outlet 40, and gas discharge outlet 50. In such exemplary embodiment, it is possible to have a continuous supply of flue gas and electrolyte and thus a continuous collection of methanol.

[0081] Another exemplary device (not shown) may be a modified version of the device of FIG.16, where methanol is collected after about 20 to 120 min of electrochemical conversion and recycled back to the cell (as electrolyte) to be further exposed to the flue gas flow and electrical field to enhance the methanol productivity.

[0082] Without being bound to theory, such production of storable fuel is challenging as the electrochemical system and process should: i) be exposed to continuous flow, ii) convert simultaneously both gases CFU and CO2, iii) use affordable electrolyte and material for electrodes, iv) consume low energy for generating DC electrical field, without using of additional power for heating or cooling to control reactions. The electrochemical system and process of the present application also include an application of storable fuel for electrical power generation in-situ. Therefore, generated fuel (methanol) may be redirected to another device for example a direct methanol fuel cell (DMFC) or indirect methanol fuel cell (RMFC), thus, creating a hybrid system.

[0083] As such, in some embodiments, the process and system of the application might serve as a source of electricity in-situ, a sustainable solution for remote locations and cold regions. Overall, the electrochemical system and process of the present application i) provide an alternative energy source.; ii) decrease GHG emissions; iii) revolutionize the ventilation systems; iv) modify and upgrade fuel cells (e.g. microbial fuel cell and direct or indirect methanol fuel cells) and subsequently makeGHG producing sectors (agriculture, wastewater facilities, building, transportation, industry) to participate in the net-zero emissions commitment.

[0084] Also provided is use of the system of the present application for producing storable fuel comprising methanol. Also provided is use of the system of the present application for reducing greenhouse gases in a flue gas and / or for mitigating greenhouse gases emissions.EXAMPLES

[0085] The following non-limiting examples are illustrative of the present application.General MethodsExample 1 - Lab

[0086] The initial investigations were conducted in the Environment Laboratory at Concordia University and in a medium size WWTP in Quebec province. The novel electrochemical convertor consisted of a bench electrochemical reactor (1250 cm3) with two metallic electrodes and adequate inlets and outlets for fluids (FIG. 4). The obtained results showed a successful conversion of GHG generated at WWTP, into methanol (117 ppm during 20 min exposure time, with a flowrate of 1 m3CH4 / h in a small device only).

[0087] Based on initial studies, it was calculated that a small lab device can decrease CO2 and CH4 by 8.320 CO2 eq tones annually. Simultaneously, it will be able to produce at least 27.445 *103ppm of methanol per year considering only the methane emission from a barn containing 100 cattle. The barn ventilation system can be equipped with an electrochemical device in chain with DMFC (or RMFC) leading to directly converting of GHG to electrical power. Preliminary tests demonstrated than more energy is produced than consumed.Example 2 - Biogas

[0088] Experimental setup was designed and employed for the conversion of dissolved natural and synthetic biogas to methanol following the electrochemical reactions (Eqs. 7, 8 and 9 above) (Amarson et al., 2018; Hazarika et al., 2019).

[0089] Natural biogas response was evaluated directly in a wastewater treatment plant of a medium size municipality in the province of Quebec, where. CO2:CH4 ratio was 60:24, while synthetic biogas, with ratio of CO2:CH4 of 50:50, was applied to study in the lab. All experiments were carried out in an electrochemical device (1 .25 L) using copper anode and lead cathode. Both electrodes were immersed in a simple aqueous electrolyte, such as effluent generated by a wastewater treatment plant without additives. DC power supply (Gwinstek Company) was employed for providing of a potential between the electrodes in the range of 5 to 100V. Before each test, both the cathode and anode were cleaned by nitric acid of 0.1 M. After cleaning with nitric acid, and then washed with distilled water (Millipore™ MilliQ gradient A10 system, 18.2 MQ cm).

[0090] The input gas rate in the range 0.5 to 2.5 m3 / h was controlled by a gas flowmeter (Air Flowmeter, OMEGA, FLDA3220ST 0.05 Ipm, 200 psi).

[0091] Temperature of biogas and electrolyte was monitored by thermocouple (Thermomart Company) throughout the research period. Tested temperatures ranged from 5°C to 32°C.

[0092] After each cycle test, the reactor was drained to make space for new electrolyte.

[0093] The produced methanol concentration was detected using UV-Vis Spectrophotometer (Evolution 201 , ThermoFisher Scientific Co.). A sample of 1 mL was added to a 50 ml balloon that contained 2 ml potassium permanganate 3% solution (Crystalline, KMnO4, 3% aqueous solution, Fisher Chemical Co), then put in a cold- water bath for 30 minutes. Then, sodium metabisulfites 10% aqueous solution (Na2O4S2, 10% aqueous solution, Fisher Chemical Co) was gradually added with a pastor pipette into the balloon to be completely colourless. Subsequently, 1 mL of chromotropic acid aqueous 5% solution (disodium salt dihydrate, CioH60sS2Na2 I 2H2O, 5% aqueous solution, Fisher Chemical Co) and 15 mL of concentrated sulfuric acid (H2SO4 96%, Fisher Chemical Co) were added to the balloon. The balloon was put in a 60°C water bath for 15 minutes and then cooled to 25°C. A spectrophotometermeasured the balloon’s content at 580 nm wavelength (Fagani et al., 2003; Rafizadeh et al., 2011 ).

[0094] In order to detect the concentration of CO2, CH4, and N2O in the natural biogas and the ratio of CO2 and CH4 in the synthetic biogas, gas chromatography (GC) (Agilent Technologies 7890B GC system, CA, USA) was used. GC system equipped with a capillary column HP-PLOT Q. The biogas sample was collected in a gas-tight syringe (about 50 mL), then it was injected directly into the GC. The carrier gas was helium. The flowrate of carrier gas was 30 mL / min. The detectors for detecting CH4, N2O, and CO2 were TCD, ECD, and FID, respectively. The temperature of the injector port and TCD detector was 200°C while the temperature of the injector port and FID detector were 170 and 150°C and the temperature of the injector port and ECD was 120°C.

[0095] The effluent used as an electrolyte was collected from wastewater treatment plant. The concentration of anions and cations in the electrolyte were determined by ion chromatography (IC) (Metrohm™ 850 Professional IC). Prior to use, the effluent was pre-treated by filtering it through a 0.45 mm filter membrane to remove the suspended solids. Liquid samples collected by 5m L sterile syringes and then injected into the IC.

[0096] The electrochemical process is highly susceptible to operational parameters. A variety of factors affect the methanol production. In order to monitor the effect of some parameters such as electrical cathodic potential, gas input time, temperature, and gas flowrate on methanol generation, several sets of tests were examined and discussed in the following sections.

[0097] Table 1 shows the composition of biogas sampled in a pilot WWTP facilities in L’Assomption, Qc, Canada in October and November 2020.Table 1 . Production of biogas componentsAverage values Average Date AverageCompound Symbol (Vol.-%) values (ppm) 2020 temperature (°C)Methane CH423.2 232014Carbon dioxide CO2 62.8 628008Nitrous oxide N2O 0.8 8201 October 18Other gases (Hydrogen, H2, NH3, N2, 02 13.2 131802Ammonia, Nitrogen,Oxygen)Methane CH417.2 172150Carbon dioxide CO2 63.8 638500Nitrous oxide N2O 1.7 17200 November 13Other gases (Hydrogen, H2, NH3, N2, 02 17.2 172340Ammonia, Nitrogen,Oxygen)Influence of cathodic potential

[0098] To investigate the effect of electrical potential on produced methanol volume, several electrical potentials were set. The experiments were carried out at different applied cathodic potentials in the range of 10.6 to 100.9 V for 30 minutes. FIG.5 displays the impact of electrical potential on methanol production in the electrochemical device. The results obtained from FIG.5 show the production of methanol turns out to be electrical potential dependent. By increasing electrical potential, the methanol concentration has been enhanced. The maximum methanol concentration found to be 116 ppm and 83.8 ppm after 30 minutes of synthetic biogas and natural biogas injection at the rate of 1 -1.5 m3 / h. The results of this experiment showed that the optimum cathodic potential for the conversion of synthetic and natural biogas to methanol was at the range of 80 to 80.8 DCV. This is an indication that the electrons passed through the electrochemical device have been used for carbon dioxide reduction. With increasing the charge passed, the methanol production will be enhanced (Hazarika et al., 2019).

[0099] A clear decrease in methanol production can be seen with increasing electrical potential from 80.8 to 100.9 V. Without being bound to theory, this is most likely due to adsorption of carbon monoxide on the electrode surface. Carbon monoxide formed from CO2 in the cathode, can absorb on the anode (Cu). Thefollowing reaction (Eq. 10) illustrates the formation of CO during CO2 reduction (Hori, 2008).C02 + H20 + 2e- CO + 2OH- (10)

[0100] This adsorption would interfere with hydrogen formation. However, electrochemical reduction of CO2 depends on the concentration of H2 or adsorbed hydrogen atoms at the electrode surface (Al-Juboori et al., 2020). The obtained conclusion is similar to the findings reported by Kortlever and co-workers (Kortlever et al., 2015).Influence of gas input time

[0101] In order to investigate the effect of the gas input time on the methanol production, several tests were carried out at different influx periods (10, 15, 20, 25, and 30 minutes).

[0102] The results showed that maximum methanol generation from synthetic and natural biogas were obtained after 30 minutes (FIG.6). As shown in FIG.6, by promoting the duration time from 5 minutes to 30 minutes, the methanol production has a significant increase. Without wishing to be bound to theory, the continuous rise in methanol generation to 30 minutes can be attributed to the enhanced collision of CH4 and CO2 molecules with the electrodes. Therefore, with increased exposure time to biogas, the CH4 oxidation and CO2 reduction have elevated and consequently, methanol formation also increased.Influence of temperature

[0103] Temperature plays an important role in electrochemical reactions. The effect of temperature on the conversion of biogas to methanol is shown in FIG.7.

[0104] FIG.7 presents the higher yields were observed within the temperature range of 20-26°C. The maximum methanol production from CO2, synthetic, and natural biogas were found to be 116.5, 88.2 and 29.4 ppm at 26.2 and 20.1 °C respectively.

[0105] As FIG.7 shows, the yield of product increase with promote temperature from 0 to 26 °C. It can be argued in general that increasing the temperature may increase reaction rates (Chaplin et al, 2003).

[0106] However, with increasing temperature (>27°C), it was observed that the methanol production rate decreased over time. Again, without being bound to theory, this may be because of the decreasing solubility of CO2 in the water. On the other hand, another reason for decreasing methanol production can be related to the viscosity of CO2 and CH4 in the biogas. Therefore, temperature is effective in the viscosity of fluids. With the increasing of temperature from 25 to 30°C the viscosity of CO2 and CH4 will increase from 1.4 x 10-5and 1 .03 x 10-5Pa s to 1 .5 x 1 o-5and 1 .1 x 10-5Pa s respectively. Thus, increase in gravity causes dense CO2 and CH4 and a decrease in methanol production (Trengove et al., 1987). Nevertheless, this decrease in methanol production is consistent with the fact that increment temperature is a limiting factor of methanol electro-synthesis.Influence of gas input flowrate

[0107] Concerning the input biogas flowrate’s effect on methanol generation, seven flowrates (from 0.5 to 2.5 m3 / h) were tested. The investigations were conducted during a period of 30 minutes under ambient temperature, where electrical potential of 80.6 V was applied. FIG.8 shows the effect of biogas flowrate on the quantity of methanol produced in an electrochemical system. The results suggested that the system performance was positively affected by the input gas flowrate modification.

[0108] The results obtained highlighted that by raising the flowrate from 0.5 to 1 m3 / h, the production rate of methanol from CO2, synthetic and natural biogas increases from 65.3 to 116.5 ppm, 70 to 84 ppm, and 11 to 29 ppm respectively. Without wishing to be bound to theory, this rise in methanol generation can be caused the increasing in CO2 mass transfer between the liquid and gas phases. On the other hand, with further increase of gas flowrate, the collision of CO2 and CH4 with electrodes enhances, and consequently, the methanol generation increases.

[0109] In addition, as observed in FIG.8, biogas flowrate higher than 2 m3 / h has an inhibitory effect on the formation of methanol. Without being bound to theory, thisunpredictable behavior is probably related to the enhancement of the turbulence in the liquid phase. On the other hand, with increasing the flowrate of input gas, the gas bubbles are condensing at the upper part of the cell, and the connection between anode and cathode is cut temporarily (Mustafa et al., 2020). Turbulence behaviour will be attenuated with increasing volume of the device.Influence of biogas input time on anions and cations of electrolyte

[0110] The effluent was collected from an activated sludge wastewater treatment plant in Quebec province and stored in a refrigerator at 5°C. Table 2 shows the composition of the pre-treated effluent of municipal WWTP.Table 2. The main characterisation of the municipal WWTP effluentParameter Symbol Average values (ppm)NH4+0.35Na+54.85 cations K+15.54Ca2+11.087Mg2+52.53NO2’ 0.17NO3’ 50.93 anions Cl’ 68.484Br 0.383SO42’ 39.69PO43-2.21

[0111] Several tests were carried out in various input time (10, 20, 30 m inutes). The concentration of anions and cations in the electrolyte were determined by ion chromatography. FIG.9 and FIG.10 show anions and cations of effluent analyses with ion chromatography.

[0112] The experiments were conducted in ambient temperature and potential 80V, was kept in all tests. FIG.11 and FIG.12 show the effect of gas input time on quantity of some existed anions and cations in the effluent after passing biogas through the electrochemical reactor.

[0113] Based on FIG.12, phosphate concentration decreased from 2.31 ppm to 0.83 ppm after 30 min of input time, while nitrate and sulphate decreased from 50.93 ppm to 22.16 ppm and from 39.69 ppm to 14.83 ppm, respectively.

[0114] The results also show that by the increasing N2O input duration to 20 minutes, the ammonium and nitrite concentrations have increased from 0.35 ppm (initial) to 1.06 ppm and from 0.17 ppm (initial) to 1.32 ppm, respectively. An increase of NO2- be attributed to reaction (11 ) (Paider et al., 2002).NO3- + 6H2O + 8e" NH3 + 9OH“ (11 )Results

[0115] Experiments were conducted with electrochemical system, analytical methods and ranges of variables are as defined above, using gas composition as shown in column 1 of Table 3, namely pure CO2, pure CPU, mixture of CO2 and CPU 50:50, and biogas from WWTP having mixture of CO2 and CPU by 64:23 (plus other gases), respectively. Results obtained in the lab are shown below in Table 3. Results obtained in the field are shown below in Table 4, which included the removal percentage for each constituent of the treated flue gas, the flue gas being natural biogas generated at a WWTP where the test was done directly in the WWTP where bioreactor was cover and biogas was pumped directly from top reactor to the electrochemical system. Finally, Table 5 shows results for the removal of impurities from effluent used as the electrolyte, where the gas in an input and output was collected for further analysis using GC analysis as defined above which permitted assessment of the gas fraction removed by the device.Table 3. Operational parameters on methanol production from GHG (biogas) in the lab and in WWTPTable 4. Operational parameters for GHG removal from biogas (CO2:CH4:N2O = 64:23:1 .7 %) produced by WWTPTable 5. Operational parameters for removal impurities from effluent used as an electrolyteConclusion

[0116] Without being bound to theory, it was demonstrated that methanol can potentially be produced from electro-conversion of biogas in WWTP. The electrochemical system and process of the present application, besides depletion of GHG contained in the biogas by conversion to methanol, can decrease remaining nitrate, phosphate, and sulphate in effluent and improve its quality to better protect water resources.

[0117] Hence, considering the circular economy, produced methanol at the WWTP on-site, can be returned to the influent as an extra carbon source for improvement of the denitrification process and decrease N2O generation.

[0118] The experimental results indicated that operational parameters are effective in the yield concentration. It is well known that the maximum methanol generation was found to be 83.82 ppm from natural biogas at the ambient temperature, 1 m3 / h flowrate, 80.6 V cathodic potential, and 30 minutes gas input time.

[0119] In sum, the main challenge to use the electrochemical system and process of the present application for methanol generation is to avoid the electrodes poisoning by produced CO during the electrochemical process and to keep operational temperature lower than 30 °C, where a small electrochemical system of less 1.5 L is considered.

[0120] Nonetheless, from an economical point of view, low energy consumption and fabrication costs are the biggest advantages of the electrochemical system and process of the present application as a green system to mitigate GHG and converting them to biofuel.

[0121] While the applicant's teachings described herein are in conjunction with various embodiments for illustrative purposes, it is not intended that the applicant's teachings be limited to such embodiments as the embodiments described herein are intended to be examples. On the contrary, the applicant's teachings described and illustrated herein encompass various alternatives, modifications, and equivalents, without departing from the embodiments described herein, the general scope of which is defined in the appended claims.REFERENCES

[0122] Abedini S, 2022. Development of an electrochemical device for converting greenhouse gases to fuel and add-value products in wastewater treatment plants, PhD dissertation, Concordia University, Montreal

[0123] Armarson L., Schmidt PS., Pandey M., Bagger A., Thygesen KS., Stephens IE., Rossmeisl J., 2018. Physical Chemistry Chemical Physics, 20(16):11152-11159.

[0124] Ashrafi, O., 2012. Estimation of greenhouse gas emissions in wastewater treatment plant of pulp & paper industry (PhD dissertation, Concordia University, Montreal).

[0125] COP26, Glasgow, UK, 2021. https: / / unfccc.int / conference / glasgow- climate-change-conference-october-november-2021

[0126] Feng, L., Palmer, P. I., Zhu, S., Parker, R. J., Liu, Y., 2022. Tropical methane emissions explain large fraction of recent changes in global atmospheric methane growth rate. Nature Communications, 13(1 ), 1378.

[0127] ECCC, Environment Climate Change Canada, Gov. Canada 2021 , https: / / www.canada.ca / en / environment-climate-change / news / 2021 / 12 / canada-publishes-progress-report-towards-2025-methane-emissions-reduction-target-and- launches-consultations-on-2030-target.html

[0128] Gov Quebec, Les Producteurs de bovins du Quebec. 2023, https: / / bovin.qc.ca / en / who-are-we / overview / at-a-glance /

[0129] Hazarika, J. and Manna, M.S., 2019. Electrochemical reduction of CO2 to methanol with synthesized Cu2O nanocatalyst: Study of the selectivity. Electrochimica Acta, 328:1350-53.

[0130] He, Z., Qian, Q., Ma, J., Meng, Q., Zhou, H., Song, J., Liu, Z. and Han, B., 2016. Water enhanced synthesis of higher alcohols from CO2 hydrogenation over a Pt / Co3O4 catalyst under Milder conditions. Angewandte Chemie Int Ed, 55(2):737- 741.

[0131] IPCC (2021 ): Summary for Policymakers. In: Climate Change 2021 : The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., et al. (eds.)]. Cambridge University.

[0132] Johnson, K. A., Johnson, D. E., 1995. Methane emissions from cattle. J Animal Science, 73(8), 2483-2492.

[0133] Kampschreur, M.J., Temmink, H., Kleerebezem, R., Jetten, M.S. and van Loosdrecht, M.C., 2009. Nitrous oxide emission during wastewater treatment. Water Research, 43(17):4093-4103.

[0134] Ma, M., Jin, B.J., Li, P., Jung, M.S., Kim, J. I., Cho, Y., Kim, S., Moon, J.H. and Park, J.H., 2017. Ultrahigh electrocatalytic conversion of methane at room temperature. Advanced Science, 4(12): 1700379.

[0135] Snip, L., 2010. Quantifying the greenhouse gas emissions of wastewater treatment plants. Environmental Science Netherlands, 60(12) 8-13.

[0136] Statistics Canada, 2023. https: / / www.statcan.gc.ca

[0137] Qiancheng M, greenhouse gases: refining the role of carbon dioxide, (2018), https: / / www.giss.nasa.gov / research / briefs / ma_01 /

[0138] Glasgow Climate Change Conference - October-November 2021 | UNFCCC. https: / / unfccc.int / conference / glasgow-climate-change-conference-october- november-2021 , (2021 , November 13).

[0139] Banihani, Q., Sierra-Alvarez, R., Field, J. A., 2009. Nitrate and nitrite inhibition of methanogenesis during denitrification in granular biofilms and digested domestic sludges. Biodegradation 20, 801-812.

[0140] Czepiel, P.M., Crill, P.M., Harriss, R.C. Methane Emissions from Municipal Wastewater Treatment Processes, Environmental Science and Technology, 27 (1993) 12, pp. 2472-2477.

[0141] Rammal M, Electrochemical reduction of CO2 to low-molecular-weight organic molecules, thesis (Ph.D.), McGill University, 2016.

[0142] Pham, H. (2020). The Questions of Who, What, and How in the Science- Policy Dialogue: Experiences from the Pan-Canadian Framework on Clean Growth and Climate Change.

[0143] Fagnani E, Melios C.B, Pezza L, Pezza H.R, Chromotropic acid- formaldehyde reaction in strongly acidic media. The role of dissolved oxygen and replacement of concentrated sulphuric acid, J. Taianta. 60 (2003) 171 -176. https: / / doi.Org / 10.1016 / S0039-9140(03)00121 -8.

[0144] Rafizadeh A, Poormohammad L, Shariati Sh, Mirzajani E, Introducing a Colorimetric Method for the Detection of methanol in Several Types of Drinks, J. Mazandaran University of Medical Sciences. 21 (2011 ) 150-152.

[0145] Al-Juboori, O., Sher, F., Hazafa, A., Khan, M.K. and Chen, G.Z., 2020. The effect of variable operating parameters for hydrocarbon fuel formation from CO2 by molten salts electrolysis. Journal of CO2 Utilization, 40:101-193.

[0146] Kortlever, R., Balemans, C., Kwon, Y., & Koper, M. T. (2015). Electrochemical CO2 reduction to formic acid on a Pd-based formic acid oxidation catalyst. Catalysis Today, 244, 58-62.

[0147] Hori, Y. I., 2008. Electrochemical CO2 reduction on metal electrodes. In Modem aspects of electrochemistry. Springer, New York, NY

[0148] Kaneco, S., liba, K., Ohta, K., Mizuno, T., & Saji, A. (1998). Electrochemical reduction of CO2 at an Ag electrode in KOH-methanol at low temperature. Electrochimica acta, 44(4), 573-578.

[0149] Azuma, M., Hashimoto, K., Hiramoto, M., Watanabe, M., & Sakata, T. (1990). Electrochemical reduction of carbon dioxide on various metal electrodes in low- temperature aqueous KHCO 3 media. Journal of the Electrochemical Society, 137(6), 1772.

[0150] Chaplin, R. P. S., & Wragg, A. A. (2003). Effects of process conditions and electrode material on reaction pathways for carbon dioxide electroreduction with particular reference to formate formation. Journal of Applied Electrochemistry, 33(12), 1107-1123.

[0151] T rengove R, Wakeham W, The viscosity of carbon dioxide, methane, and sulfur hexafluoride in the limit of zero density, Journal of Physical and Chemical Reference Data, 16.2 (1987) 175-187.

[0152] Mustafa N, Mohd Shariff A, Tay W, Abdul Halim H, Mhd Yusof S, Mass transfer performance study for CH4 absorption into non-precipitated potassium carbonate promoted with glycine using packed absorption column, Sustainability, 12.9 (2020) 3873.

[0153] Paidar M, Bouzek K, Bergmann H, Influence of cell construction on the electrochemical reduction of nitrate, Chemical Engineering Journal, 85.2-3 (2002) 99- 109.

[0154] Ozgur Y, Gdncu S, The effect of process parameters on use of immobilized algae culture for nitrogen and phosphorus removal from wastewater, International Journal of Environmental Science and Technology, 20 (2023) 6015-6026.

Claims

CLAIMS1 . An electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert CO2 and CH4 into methanol; and recovering the produced methanol; wherein the electrochemical conditions comprise a temperature of about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

2. An electrochemical process for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the process comprising: injecting the flue gas into an electrochemical cell comprising electrodes and an electrolyte; applying a constant voltage gradient from about 0.2V / cm to about 15V / cm under electrochemical conditions to at least partially convert CO2 and CH4 into methanol; and recovering the produced methanol; wherein the flue gas is injected at a ratio of a volume of the gas flow proportional to a volume of the electrochemical cell of about 400 to about 2500 over a one hour period, wherein the electrochemical conditions comprise a temperature of about 5 °C to about 70 °C, a pressure of about atmospheric pressure, and the process is conducted under continuous flow for about 5 minutes to about 120 minutes.

3. The electrochemical process of claim 1 or 2, wherein the flue gas further contains N2O which is at least partially converted into nitrogen derivatives comprising nitrogen gas, nitrates or mixtures thereof.

4. The electrochemical process of claim 1 or 2, wherein the flue gas further contains CO which is at least partially converted into methanol.

5. The electrochemical process of any one of claims 1 to 4, wherein the flue gas is not subjected to separation prior to injection into the electrochemical cell.

6. The electrochemical process of any one of claims 1 to 5, wherein the electrolyte is wastewater, gray water, effluent water, tap water, or mixtures thereof.

7. The electrochemical process of any one of claims 1 to 5, wherein the electrolyte comprises at least one of phosphates, nitrates, sulphates and ammonium.

8. The electrochemical process of any one of claims 1 to 7, wherein the electrolyte does not require the addition of a catalyst.

9. The electrochemical process of any one of claims 1 to 8, wherein a voltage applied is from about 75V to about 95V.

10. The electrochemical process of any one of claims 1 to 8, wherein a voltage applied is from about 78V to about 92V.11 .The electrochemical process of any one of claims 1 to 10, wherein the voltage gradient is from about 1V / cm to about 12V / cm.

12. The electrochemical process of any one of claims 1 to 10, wherein the voltage gradient is from about 6V / cm to about 10V / cm.

13. The electrochemical process of any one of claims 1 to 12, wherein the ratio of volume of gas flow proportional to volume of the electrochemical cell is about 500 to about 1200 over a one hour period.

14. The electrochemical process of any one of claims 1 to 13, wherein the ratio of volume of gas flow proportional to volume of the electrochemical cell is about 600 to about 1100 over a one hour period.

15. The electrochemical process of any one of claims 1 to 14, wherein the temperature is provided by a temperature of the injected flue gas.

16. The electrochemical process of any one of claims 1 to 14, wherein the electrochemical conditions comprise a temperature of about 10 °C to about 30 °C.

17. The electrochemical process of any one of claims 1 to 14, wherein the electrochemical conditions comprise a temperature of about 15 °C to about 25°C.

18. The electrochemical process of any one of claims 1 to 17, wherein the process is conducted under continuous gas flow for about 10 minutes to about 60 minutes.

19. The electrochemical process of any one of claims 1 to 17, wherein the process is conducted under continuous gas flow for about 15 minutes to about 30 minutes.

20. The electrochemical process of any one of claims 1 to 19, wherein a portion of the CO2 and CH4 contained in the flue gas is at least partially converted into formic acid and / or formates.21 . The electrochemical process of any one of claims 1 to 20, further comprising, after the process is conducted under continuous flow, replacing the electrolyte and repeating injecting, applying and recovering.

22. An electrochemical system for at least partially converting CO2 and CH4 contained in a flue gas into methanol, the system comprising: an electrochemical cell configured to contain an electrolyte, and comprising: a metallic anode and a metallic cathode configured for being in contact with the electrolyte and for being electrically connected to a power source configured to apply a voltage gradient between the metallic anode and the metallic cathode; a gas inlet configured for injecting flue gas in the electrochemical cell;an electrolyte inlet configured to supply the electrolyte; a product outlet configured for recovering the electrochemical products; and a gas discharge outlet configured to discharge gas produced in the electrochemical system.

23. The electrochemical system of claim 22, wherein the metallic anode is a copper anode.

24. The electrochemical system of claim 22 or 23, wherein the metallic cathode is a lead cathode.

25. The electrochemical system of any one of claims 22 to 24, wherein the distance between the anode and the cathode is about 0.5 cm to about 80 cm.

26. The electrochemical system of any one of claims 22 to 24, wherein the distance between the anode and the cathode is about 1 cm to about 40 cm.

27. The electrochemical system of any one of claims 22 to 24, wherein the distance between the anode and the cathode is about 5 cm to about 20 cm.

28. The electrochemical system of any one of claims 22 to 27, wherein the flue gas further contains N2O which is to be at least partially converted into nitrogen derivatives comprising nitrogen gas, nitrates or mixtures thereof.

29. The electrochemical system of any one of claims 22 to 28, wherein the flue gas further contains CO which is to be at least partially converted into methanol.

30. The electrochemical system of any one of claims 22 to 29, wherein the flue gas is not to be subjected to separation prior to injection into the electrochemical cell.31 .The electrochemical system of any one of claims 22 to 30, wherein the electrolyte is configured to be wastewater, gray water, effluent water, tap water or mixtures thereof.

32. The electrochemical system of any one of claims 22 to 30, wherein the electrolyte configured to comprise at least one of phosphates, nitrates, and sulphates.

33. The electrochemical system of any one of claims 22 to 32, wherein the electrolyte configured to not require the addition of a catalyst.

34. The electrochemical system of any one of claims 22 to 33, wherein a voltage applied is configured to be from about 75V to about 95V.

35. The electrochemical system of any one of claims 22 to 33, wherein the voltage applied is configured to be from about 78V to about 92V.

36. The electrochemical system of any one of claims 22 to 35, wherein the potential gradient is configured to be from about 1V / cm to about 12V / cm.

37. The electrochemical system of any one of claims 22 to 35, wherein the potential gradient is configured to be from about 6V / cm to about 10V / cm.

38. The electrochemical system of any one of claims 22 to 37, wherein the flue gas is configured to be injected at a ratio of volume of the gas flow proportional to a volume of the electrochemical cell of about 400 to about 2500 over a one hour period.

39. The electrochemical system of any one of claims 22 to 37, wherein the flue gas is configured to be injected at a ratio of volume of the gas flow proportional to a volume of the electrochemical cell of about 500 to about 1200 over a one hour period.

40. The electrochemical system of any one of claims 22 to 39, the electrochemical system is configured to be operated at a temperature of about 5 °C to about 70 °C.41 .The electrochemical system of claim 40, wherein the temperature is to be provided by a temperature of the flue gas to be injected.

42. The electrochemical system of any one of claims 22 to 39, wherein the electrochemical system is configured to be operated at a temperature of about 10 °C to about 30 °C.

43. The electrochemical system of any one of claims 22 to 39, wherein the electrochemical system is configured to be operated at a temperature of about 15 °C to about 25 °C.

44. The electrochemical system of any one of claims 22 to 43, wherein the electrochemical system is configured to be operated under continuous flow for about 10 minutes to about 60 minutes.

45. The electrochemical system of any one of claims 22 to 43, wherein the electrochemical system is configured to be operated under continuous flow for about 15 minutes to about 30 minutes.

46. The electrochemical system of any one of claims 22 to 45, electrochemical system is configured, after being operated under continuous flow, for replacing the electrolyte and repeating injecting, applying and recovering.

47. Use of the process of any one of claims 1 to 21 , for producing storable fuel comprising methanol.

48. Use of the process of any one of claims 1 to 21 , for reducing greenhouse gases in a flue gas.

49. Use of the process of any one of claims 1 to 21 , for mitigating greenhouse gases emissions.

50. Use of the system of any one of claims 22 to 46, for producing storable fuel comprising methanol.51 . Use of the system of any one of claims 22 to 46, for reducing greenhouse gases in a flue gas.

52. Use of the system of any one of claims 22 to 46, for mitigating greenhouse gases emissions.

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