WO2022112658A1

WO2022112658A1 - Method and apparatus for producing formate or formic acid from carbon dioxide and use

Info

Publication number: WO2022112658A1
Application number: PCT/FI2021/050810
Authority: WO
Inventors: Kristian Melin; Markus HURSKAINEN; Noora Kaisalo; Pekka Simell
Original assignee: VTT Technical Research Centre of Finland Ltd
Current assignee: VTT Technical Research Centre of Finland Ltd
Priority date: 2020-11-30
Filing date: 2021-11-26
Publication date: 2022-06-02
Anticipated expiration: 2023-05-30
Also published as: FI20206216A1

Abstract

The invention relates to a method and an apparatus for producing a formate or formic acid from carbon dioxide. A bicarbonate solution (5) comprising at least bicarbonate is formed from a mixture (2) which comprises at least carbon dioxide and which further comprises carbonate, ammonia and/or hydroxide (3), and the bicarbonate solution (5) is treated by a reaction with a metal catalyst in a reactor (8), in which hydrogen and/or carbon monoxide (6) is supplied to the reactor and temperature is 10 - 70 °C and pressure is 1 – 100 bar during the reaction, in order to produce the formate (7), and optionally the formic acid (11) is produced from the formate. Further, the invention relates to the use of the method.

Description

METHOD AND APPARATUS FOR PRODUCING FORMATE OR FORMIC ACID FROM CARBON DIOXIDE AND USE

FIELD

The application relates to a method defined in claim 1 and an apparatus defined in claim 14 for for producing a formate or formic acid from carbon di oxide. Further, the application relates to a use of the method defined in claim 16.

BACKGROUND

Known from the prior art is to produce dif ferent formates and formic acids by means of different methods, typically from fossil raw materials.

The formic acid may be produced from synthe sis gas such that firstly methyl formate is formed and after that the formic acid is formed from the methyl formate. The main problems are associated with work-up of hydrolysis mixtures. Because of the unfavorable po sition of the equilibrium, reesterification of the methanol and formic acid to the methyl formate occurs rapidly during a separation of unreacted methyl for mate. Problems also arise in the selection of suffi ciently corrosion-resistant materials.

Further, a formic acid production from carbon dioxide has been demonstrated in laboratory scale. However, the formic acid production from carbon diox ide requires a complex and expensive catalytic system which is difficult to scale up, and separation of cat alysts and solvents requires a lot of energy.

OBJECTIVE

The objective is to solve the above problems. Further, the objective is to disclose a new type of method and apparatus for producing a formate or formic acid. Further, the objective is to disclose a simple method for producing the formate or formic acid from carbon dioxide. Further, the objective is to utilize a captured carbon dioxide for producing the formate or formic acid.

SUMMARY

The method and apparatus and use are charac terized by what are presented in the claims.

In the method and apparatus, a bicarbonate solution comprising at least bicarbonate is formed from a mixture which comprises at least carbon dioxide and the bicarbonate solution is treated by a reaction with a metal catalyst in a reactor in order to produce a formate, and optionally to produce a formic acid from the formate.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing, which is included to provide a further understanding of the invention and constitutes a part of this specification, illus trates some embodiments of the invention and together with the description help to explain the principles of the invention. In the drawing:

Fig. 1 is a flow chart illustration of a pro cess according to one embodiment.

DETAILED DESCRIPTION

In a method for producing a formate or formic acid from carbon dioxide, the method comprises: form ing a bicarbonate solution (5) comprising at least bi carbonate from a mixture (2) which comprises at least carbon dioxide and which further comprises carbonate, ammonia and/or hydroxide (3), and treating the bicar bonate solution (5) by a reaction with a metal cata lyst in a reactor (8), in which hydrogen and/or carbon monoxide (6) is supplied to the reactor and tempera ture is 10 - 70 °C and pressure is 1 - 100 bar during the reaction, in order to produce the formate (7). Op- tionally the formic acid (11) can be produced from the formate.

An apparatus for producing a formate or for mic acid from carbon dioxide, wherein the apparatus comprises at least one equipment (4) into which a mix ture (2) which comprises at least carbon dioxide and which further comprises carbonate, ammonia and/or hy droxide (3) is subjected for forming a bicarbonate so lution (5) comprising at least bicarbonate, and at least one reactor (8) in which the bicarbonate solu tion is treated by a reaction with a metal catalyst at temperature of 10 - 70 °C and pressure of 1 - 100 bar and at least one feeding device for supplying the hy drogen and/or carbon monoxide (6) into the reactor in order to produce the formate (7). Optionally the for mic acid (11) can be produced from the formate.

Some embodiments of the method and the appa ratus are shown in Fig. 1.

In this context, the bicarbonate solution (5) means any solution, which contains at least bicar bonate and solvent, e.g. water, ethanol, other solvent or their combinations. The bicarbonate solution is CCy-derived carbonate solution. In one embodiment, the solvent of the bicarbonate solution comprises water and ethanol. The bicarbonate solution can comprise al so other components than the bicarbonate and the sol vent. The bicarbonate solution can comprise one or more components. In one embodiment, the bicarbonate solution comprises at least bicarbonate and/or car bonate. In one embodiment, the bicarbonate is formed in the mixture comprising at least carbon dioxide, such as a captured CCy, and further carbonate, ammonia and/or hydroxide. In one embodiment, the carbonate is selected from sodium carbonate, ammonium carbonate, potassium carbonate, magnesium carbonate or their com binations. In one embodiment, the bicarbonate is sodi- um bicarbonate, ammonium bicarbonate, potassium bicar bonate, magnesium bicarbonate or their combinations.

In this context, the mixture (2) means any mixture comprising at least carbon dioxide, such as a captured carbon dioxide. The mixture is in a liquid form, e.g. solution, aqueous solution or the like. In one embodiment, the mixture comprises water, i.e. the carbon dioxide is in an aqueous solution. Further, the mixture comprises carbonate, ammonia and/or hydroxide. The mixture can comprise also other components. The mixture can comprise one or more components. In one embodiment, the carbonate is selected from sodium car bonate, ammonium carbonate, potassium carbonate, mag nesium carbonate or their combinations. The mixture may comprise carbonate, ammonia and/or hydroxide, or carbonate, ammonia and/or hydroxide may be added to the mixture.

In this context, the formate (7) means any formate, formate salt, formate product or the like which is formed from the bicarbonate solution compris ing the bicarbonate.

In this context, the formic acid (11) means any formic acid, formic acid product or the like which is formed from the bicarbonate solution comprising the bicarbonate and/or from the formate.

In one embodiment, the carbon dioxide is cap tured and the mixture (2) is formed. In one embodi ment, the mixture may comprise carbonate, ammonia and/or hydroxide, or carbonate, ammonia and/or hydrox ide may be added to the mixture. In one embodiment, the carbon dioxide is captured into a solution. In one embodiment, the carbon dioxide is captured directly into the mixture. In one embodiment, the carbon diox ide is captured, a blend or stream comprising the car bon dioxide is formed, and the mixture (2) is formed from said blend or stream. In one embodiment, the car bon dioxide is captured, a blend or stream comprising the carbon dioxide is formed, at least one fraction or phase is separated from said blend or stream and the mixture (2) is formed from said fraction or phase. In one embodiment, the blend or stream or their fraction may comprise carbonate, ammonia and/or hydroxide, or carbonate, ammonia and/or hydroxide may be added to the the blend or stream or their fraction or to the mixture which is formed. In one embodiment, the carbon dioxide is captured from a gas (1) which comprises carbon dioxide, e.g. from raw gas, biomass derived gas, biogas, gas from biomass pyrolysis, synthesis gas, exhaust gas, flue gas, hydrogen containing gas, gasification gas, fermentation gas, gas from biomass treating process, gas from black liquor process or the like or their combinations. In one embodiment, the carbon dioxide is captured from a liquid which com prises carbon dioxide. The carbon dioxide may be cap tured by means of any suitable method or device (12), e.g. capture device, ejector or the like, from the gas or liquid. In one embodiment, the apparatus comprises at least one capture device or ejector for capturing the carbon dioxide.

In one embodiment, the carbon dioxide is cap tured from a gas into a solution, such as into the mixture (2). In one embodiment, the gas comprising carbon dioxide is treated in a treatment comprising at least one capture device, e.g. a column, and the car bon dioxide is captured from the gas into the solution in the treatment. Any suitable device can be used to capture the carbon dioxide. In one embodiment, the so lution comprises the carbonate, ammonia and/or hydrox ide. In one embodiment, the carbonate, ammonia and/or hydroxide may be added in connection with the capture of the carbon dioxide for forming the mixture. In one embodiment, the carbonate, ammonia and/or hydroxide may be added later into the mixture. In one embodi ment, at least one fraction or phase is separated af- ter the capturing, e.g. a gas phase is separated from a liquid phase and the mixture is formed from the liq uid phase. In one embodiment, the apparatus comprises at least one separation device for separating desired phases or fractions. The mixture may be formed from a predetermined phase or fraction.

In one embodiment, the gas comprising carbon dioxide is treated in a treatment comprising at least one ejector stage wherein a motive medium, e.g. at high pressure, is injected to at least one ejector of the ejector stage and the gas is sucked into the same ejector in which the gas is mixed with the motive me dium for forming a blend of the gas and motive medium. Then the carbon dioxide is captured into the blend. In one embodiment, the blend of the gas and motive medium is used as the mixture or the mixture which comprises CO2 is separated, e.g. as a liquid phase, from the blend of the gas and motive medium. In one embodiment, the gas (1) comprising carbon dioxide is treated in at least one ejector stage for capturing the carbon diox ide wherein a motive medium is injected to at least one ejector of the ejector stage and the gas is sucked into the same ejector in which the gas is mixed with the motive medium for forming a blend of the gas and motive medium, and the mixture is formed from the blend of the gas and motive medium or from a liquid phase of the blend. Preferably, the liquid phase is a carbon dioxide rich phase. In one embodiment, the method and apparatus may comprise more than one ejec tor stages. In one embodiment, gas and liquid phases may be separated after the ejector stage. In one em bodiment, the apparatus comprises at least one separa tion device for separating the gas and liquid phases. In one embodiment, the carbon dioxide can be captured from the gases comprising CCy by means of the method or apparatus presented in patent application WO 2018206850. In one embodiment, the carbonate, ammonia and/or hydroxide is added to the blend or the mixture, or the blend or the mixture comprises the carbonate, ammonia and/or hydroxide. In one embodiment, the car bonate, ammonia and/or hydroxide is added in connec tion with the ejector stage, or before the ejector stage, or after the ejector stage. In one embodiment, the carbonate, ammonia and/or hydroxide is added to the liquid phase or to the mixture after the separa tion.

In one embodiment, the mixture (2) comprises the carbonate, ammonia and/or hydroxide. In one embod iment, the CCy-containing stream from the capture is subjected to the mixture comprising the carbonate, am monia and/or hydroxide. In one embodiment, the CCy is captured into the mixture comprising the carbonate, ammonia and/or hydroxide. In one embodiment, a blend or stream comprising the carbon dioxide comprises the carbonate, ammonia and/or hydroxide, and the mixture is formed from the blend or stream or from a fraction or phase of the blend or stream. In one embodiment, the predetermined carbonate, ammonia and/or hydroxide (3) is added to the mixture. In one embodiment, the predetermined carbonate, ammonia and/or hydroxide is added to the blend or stream comprising the carbon di oxide in connection with the capture of the carbon di oxide or after the capture, or to the phase or frac tion separated from the blend or stream. In one embod iment, the predetermined carbonate, ammonia and/or hy droxide is added in one or more steps.

In one embodiment, the mixture (2) and its components, such as CCy and further carbonate, ammonia and/or hydroxide are given to react in a solution, such as an aqueous solution, in order to form bicar bonates. In one embodiment, CCy and carbonate, ammonia and/or hydroxide are given to react in the mixture for forming bicarbonates. In one embodiment, the bicar bonate is formed in the mixture. In one embodiment, the bicarbonate is formed in connection with the cap turing or after the capture of the carbon dioxide. In one embodiment, the bicarbonate is formed in connec tion with the separation. In one embodiment, the bi carbonate is formed after the capture of the carbon dioxide and the separation.

The formation of the bicarbonates may be car ried out in any suitable equipment (4) or device. In one embodiment, the equipment (4) in which the bicar bonate is formed may be any treatment device, reactor, mixer, vessel, pipe, other suitable equipment, or their combinations.

In one embodiment, the bicarbonate solution (5) is formed from the mixture (2). In one embodiment, the bicarbonate solution (5) is formed directly from the mixture. In one embodiment, the bicarbonate solu tion (5) is formed by separating or recovering the bi carbonates from the mixture and by forming the bicar bonate solution from the bicarbonates. In one embodi ment, the bicarbonate solution (5) is the mixture (2).

In one embodiment, the bicarbonate solution (5) is formed directly from the mixture (2) comprising the captured carbon dioxide, without a purification of the mixture. The mixture or the bicarbonate solution may comprise impurities, e.g. SCy, ¾S, NH₃, HC1, S0₄ ^2- and/or Cl-. By means of the process of the invention CCy-containing gases which comprise impurities can be converted into the formates and formic acids.

The hydrogen and/or carbon monoxide (6) is supplied to the reactor (8). In one embodiment, at least hydrogen is supplied to the reactor. In one em bodiment, at least carbon monoxide is supplied to the reactor. In one embodiment, synthesis gas is supplied to the reactor. In one embodiment, gas comprising car bon monoxide is supplied to the reactor. In one embod iment, gas comprising carbon monoxide and hydrogen is supplied to the reactor. In one embodiment, hydrogen, carbon monoxide, synthesis gas, gas comprising carbon monoxide and/or gas comprising carbon monoxide and hy drogen is supplied to the reactor. In one embodiment, the apparatus comprises at least one feeding device for supplying the hydrogen, carbon monoxide, synthesis gas, gas comprising carbon monoxide and/or gas com prising carbon monoxide and hydrogen into the reactor. Hydrogen containing gases, e.g. unused hydrogen from industrial sites, and/or carbon monoxide containing gases, e.g. from coke ovens, pyrolysis or gasifica tion, may be used as raw materials to hydrogenate bi carbonates into the formates in the reactor. In one embodiment, the hydrogen may be fed in connection with a capture of the carbon dioxide, e.g. to a first or second ejector in which the gas comprising carbon di oxide is treated, or after the capture, and then the mixture (2) further comprises the hydrogen.

In the reactor (8), the bicarbonate solution (5) is treated to form the formate (7), i.e. the bi- carbonate solution is hydrogenated into the corre sponding formate with the metal catalyst.

In one embodiment, temperature is 15 - 50 °C, in one embodiment 20 - 45 °C, during the reaction in the reactor (8). In one embodiment, pressure is 20 - 60 bar, in one embodiment 30 - 50 bar, during the re action in the reactor (8). In one embodiment, reaction time is 0.5 - 2 hours, in one embodiment about 1 hour, in the reactor. In one embodiment, pressure of the hy drogen is 20 - 40 bar, in one embodiment about 30 bar. Preferably, the reaction is performed in presence of the hydrogen and/carbon monoxide in the reactor. In one embodiment, the reaction is performed in presence of at least the hydrogen in the reactor.

In one embodiment, any suitable metal cata- lyst may be used in the reactor. In one embodiment, the catalyst comprises precious metal, such as Pd, Pt, Ru, Au or other suitable precious metal. In one embod- iment, the catalyst comprises a carrier material, and the carrier material of the catalyst comprises acti vated carbon, AI₂O₃, TiCy, ZnO, ZrCy, MgO, SiCy, CeCy, CeZrO_x or other suitable carrier material. In one em bodiment, the reactor comprises a catalyst bed or at least one catalyst element. In one embodiment, the catalyst bed of the reactor comprises at least the metal catalyst. The catalyst bed may further comprise bed material, e.g. sand. Any suitable bed material may be used. In one embodiment, the catalyst element com prises at least the metal catalyst.

The reactor (8) may be any reactor, device or pressurized vessel or the like in which the formate (7) can be produced under heating and pressure. In one embodiment, the reactor is a fixed bed reactor, trick le bed reactor, loop reactor or the like.

In one embodiment, the formate (7) can be used as such or can be treated, post-treated or sup plied to a next process or a next process step after the reactor (8). In one embodiment, the formate is re covered after the reactor. In one embodiment, the for mate is treated to form the formic acid (11).

In one embodiment, the formic acid (11) is produced. In one embodiment, a strong acid (10), e.g. phosphoric acid, HC1 or sulphuric acid, is added to the formate, and the formate is treated, e.g. by de composing, in order to form the formic acid. In one embodiment, the phosphoric acid is added to the for mate, and the formate is treated by decomposing in or der to form the formic acid and phosphate salt. In one embodiment, a formed salt product, e.g. ammonium phos phate or magnesium chloride, produced as a by-product in the production of the formic acid is decomposed by a heat treatment or by heating, e.g. at 200 °C, back to a strong acid, e.g. molten phosphoric acid or HC1, and to a base, e.g. ammonia or magnesium compound. The formed salt product which is produced as a by-product in the production of the formic acid may be, for exam ple, ammonium phosphate, sodium phosphate, potassium phosphate or magnesium chloride. In one embodiment, the formed strong acid, e.g. phosphoric acid or HC1, can be recycled to the production of the formic acid in which the formate is decomposed into the formic ac id. In one embodiment, the formed ammonia may be recy cled to the capture of the carbon dioxide or to the mixture. In one embodiment, sulphuric acid is used as the strong acid in the production of the formic acid, and the spent sulphuric acid containing sulphates can be regenerated in a process where the sulphates are thermally decomposed into SCy, and the sulphuric acid is produced back from SCy. In the formate and formic acid production, the acids and bases may be recycled, and waste salt production can be avoided. The formic acid may be produced in any reactor, device, vessel or the like.

In one embodiment, methyl formate or ethyl formate is produced. In one embodiment, methyl formate or ethyl formate is formed from a formed formate or a formic acid. In one embodiment, methanol or ethanol is produced. In one embodiment, formic acid and methanol is formed from the methyl formate.

In one embodiment, methyl formate or methanol is produced. In one embodiment, the methyl formate is formed by converting a formed formate, e.g. ammonium formate, into a formic acid in a solution comprising methanol by adding a small amount of strong acid, e.g. sulphuric acid that catalyses a reaction of the formed acid and methanol into the methyl formate. The methyl formate can be separated, for example by a reactive distillation, evaporation or the like method. The methanol can be formed by hydrogenation of the methyl formate. Instead of methanol ethanol can be used to produce ethyl formate. In one embodiment, the formate is decomposed into hydrogen or into hydrogen and CCy. In one embodi ment, the formate, e.g. ammonium formate, is decom posed into hydrogen and CCy, and further for example ammonium bicarbonate and/or ammonium carbonate, at el evated temperatures, and optionally by using metal catalyst, and the remaining liquid may be returned to the reactor. In one embodiment, the formate solution can be used as a storage medium for both hydrogen and CO2· The formed mixture of CO2 and hydrogen can be further converted to a product, such as to fuel or chemicals, thereby storing renewable electricity ac cording to Power to X concepts.

In one embodiment, the formate product can be used as a hydrogen donor in transfer hydrogenation where a substance, such as biocrude, liquid organic hydrogen carrier etc., is hydrogenated directly with the hydrogen donor under mild process conditions in stead of employing hydrogen gas at high pressure and temperature.

In one embodiment, the formate (7) is formed at one or more process stages. In one embodiment, the carbon dioxide is captured in more than one capture steps. In one embodiment, the formic acid (11) is formed in more than one reaction steps and reactors.

The capture steps or reaction steps may be sequential process steps or parallel process steps.

In one embodiment, the method and apparatus are based on a continuous process. In one embodiment, the method and apparatus can be used in a production of formate, e.g. sodium formate, ammonium formate, potassium formate or magne sium formate, in a production of formic acid, in a treatment of captured carbon dioxide, in a production of a chemical or liquid for using as a carrier of car bon dioxide and/or hydrogen, in a production of metha nol, or their combinations. In one embodiment, the liquid is used as the carrier of carbon dioxide and/or hydrogen for storing energy from renewable power pro duction, production of methyl and ethyl, production of formate or production of methanol.

Thanks to the invention, a simple process is provided to produce different formates and formic ac ids from the carbon dioxide based raw material, e.g. from CCy-containing gases. For example, industrial sources which comprise carbon dioxide can be used as raw material for producing the formates and formic ac ids. Further, a production of waste salts can be avoided or prevented in this process.

The method and apparatus offer a possibility to produce the formates and formic acids with good properties easily, and energy- and cost-effectively. The present invention provides an industrially appli cable, simple and affordable way to produce the de sired formate and formic acid products. The method and apparatus are easy and simple to realize in connection with production processes.

EXAMPLES

Fig. 1 presents some embodiments of the pro cess for producing formate from CCy-containing mixture and formic acid from the formate.

The apparatus comprises at least one equip ment (4) into which a mixture (2) which comprises at least carbon dioxide and which further comprises car bonate, ammonia and/or hydroxide (3) is subjected for forming a bicarbonate solution (5) comprising at least bicarbonate. The bicarbonate solution (5) may comprise also carbonate. The carbon dioxide is captured from a gas comprising CCy (1) in a capture stage (12) com prising a capture device of the carbon dioxide. If the capture device is an ejector, a motive medium (13) can be fed to the ejector. The capture stage (12) may com prise a separation device for separating a purified gas (14) from the mixture (2) comprising at least the carbon dioxide. The mixture (2) may comprise car bonate, ammonia and/or hydroxide, or carbonate, ammo nia and/or hydroxide (3) are added to the mixture be fore the equipment (4) or in the equipment. The bicar bonate solution (5) comprising at least bicarbonate, and in one embodiment also carbonate, is formed in the equipment which may be, for example, a pipe, vessel or mixer and in which the components of the mixture react to form the bicarbonates.

Further, the apparatus comprises at least one reactor (8). At least one feeding device is arranged to supply the hydrogen and/or carbon monoxide (6) into the reactor (8). The bicarbonate solution (5) is treated by a reaction with a metal catalyst at temper ature of 10 - 70 °C, in one embodiment 15 - 50 °C, and pressure of 1 - 100 bar in the reactor, and the for mate (7) is formed.

The formic acid (11) may be produced from the formate (7). The formate (7) is fed to a formic acid reactor (9). Further, a strong acid (10), e.g. phos phoric acid or HC1 or sulphuric acid, is supplied to the formic acid reactor (9), and the formic acid (11) is formed from the formate.

Example 1

In this example, the production of the sodium formate and the formic acid is performed according to the apparatus of Fig. 1.

CO2 is captured and mixed with sodium car bonate to form a mixture which is an aqueous solution. In the mixture CCy reacts with the sodium carbonate to form sodium bicarbonate, and a bicarbonate solution comprising the sodium bicarbonate is formed. The bi carbonate solution is supplied to a reactor. Further, hydrogen is supplied to the reactor. In the reactor, the bicarbonate solution is hydrogenated with a metal catalyst at temperature of 20 - 50 °C and in pressure of 30 - 60 bar for forming the sodium formate.

Further, the formic acid is formed from the sodium formate. A phosphoric acid is added to the the sodium formate, and the sodium formate is treated with the phosphoric acid by decomposing the sodium formate to the formic acid and sodium phosphate.

Example 2

In this example, the production of the ammo nium formate and the formic acid is performed accord ing to the apparatus of Fig. 1.

CO2 is captured and mixed with ammonium car bonate to form a mixture which is an aqueous solution. In the mixture CO2 reacts with the ammonium carbonate to form ammonium bicarbonate, and a bicarbonate solu tion comprising the ammonium bicarbonate is formed. The bicarbonate solution is supplied to a reactor. Further, hydrogen is supplied to the reactor. In the reactor, the bicarbonate solution is hydrogenated with a metal catalyst at temperature of 20 - 50 °C and in pressure of 30 - 60 bar for forming the ammonium for mate.

Further, the formic acid is formed from the ammonium formate. A phosphoric acid is added to the the ammonium formate, and the ammonium formate is treated with the phosphoric acid by decomposing the ammonium formate to the formic acid and ammonium phos phate. The ammonium phosphate may be decomposed back to gaseous ammonia and molten phosphoric acid. The phosphoric acid may be recycled to the production of the formic acid. The ammonia may be recycled to the capture of the carbon dioxide or to the mixture.

Example 3

In this example, the continuous production of the ammonium formate was examined. Ammonium bicarbonate was formed from CO2, and a bicarbonate solution comprising the ammonium bicar bonate was formed. The bicarbonate solution included water + 1 M ammonium bicarbonate (50 wt%) and ethanol (50 wt%). The bicarbonate solution was supplied to a reactor, and liquid feed was 0.09 ml/min. Further, hy drogen, 50 ml/min, was supplied to the reactor. In the reactor, the bicarbonate solution was hydrogenated with 1.1 g Pd/AC (5 wt%) catalyst, in which AC is ac tivated carbon, at temperature of about 21 °C and in pressure of 30 bar for forming the ammonium formate.

It was observed from the test that yields of the ammonium formate were similar, about 30 - 42 %, in relation to time during the continuous process.

Example 4

In this example, the bicarbonate solution and formate were formed.

Carbon dioxide was captured and absorbed into an aqueous solution which comprised ammonium car bonate. In the solution the carbon dioxide reacted with the ammonium carbonate to form ammonium bicar bonate. Then the bicarbonate solution was formed, and the bicarbonate solution comprised ammonium bicar bonate and ammonium carbonate. The ammonium formate was formed from the bicarbonate solution.

Example 5

In this example, the carbonate and bicar bonate were compared in the production of the formate. The carbonate was ammonium carbonate, and the bicar bonate was ammonium bicarbonate.

Carbonate solutions comprising the ammonium carbonate or ammonium bicarbonate were fed to a reac tor which has 2 g Pd/AC (1 wt%) -catalyst, in which AC is activated carbon. The reactions were performed in the reactor. The pressure of hydrogen was 30 bar and temperature was about 20 °C in the reactor.

It was observed from this test that yield of the formate was 16.1 %, when the carbonate solution comprising the ammonium carbonate was used, and 31.6 %, when the carbonate solution comprising the ammonium bicarbonate was used.

Example 6

In this example, the bicarbonates were com pared in the production of the formate. The bicar bonates were ammonium bicarbonate, sodium bicarbonate and potassium bicarbonate.

The reactions were performed as batch experi ments in 50 ml autoclave. Reaction time was 1 h. The pressure of hydrogen was 30 bar in the autoclave. 1 M bicarbonate solution in ¾0 was fed to the autoclave which has 0.1 g Pd/AC -catalyst, in which AC is acti vated carbon.

It was observed from this test that yield of the formate was best, about 50 %, when potassium bi carbonate was used.

Example 7

In this example, the solvents of the bicar bonate solutions were compared in the production of the ammonium formate.

The bicarbonate solutions included ammonium bicarbonate. The bicarbonate solution A included 20 ml ¾0 and the ammonium bicarbonate. The bicarbonate so lution B included 15 ml ¾0 + 10 ml ethanol and the ammonium bicarbonate. The bicarbonate solutions were fed to a reactor which has Pd(5 wt%)/AC -catalyst, in which AC is activated carbon. Reaction time was 1 h. The pressure of hydrogen was 30 bar and temperature was 20 °C in the reactor. It was observed from this test that yield of the ammonium formate was 30.4 %, when the bicarbonate solution A comprising ¾0 was used, and 49.3 %, when the bicarbonate solution B comprising ¾0 and ethanol was used.

The reactor and other devices and equipments of the process used in Fig. 1 are known per se in the art, and therefore they are not described in any more detail in this context.

The method and apparatus are suitable in dif ferent embodiments for producing formates and formic acids from different CCy based raw materials.

The invention is not limited merely to the examples referred to above; instead many variations are possible within the scope of the inventive idea defined by the claims.

Claims

1. A method for producing a formate or formic acid from carbon dioxide, characterized in that the method comprises - forming a bicarbonate solution (5) comprising at least bicarbonate from a mixture (2) which com prises at least carbon dioxide and which further comprises carbonate, ammonia and/or hydroxide (3), and - treating the bicarbonate solution (5) by a reac tion with a metal catalyst in a reactor (8), in which hydrogen and/or carbon monoxide (6) is sup plied to the reactor and temperature is 10 - 70 °C and pressure is 1 - 100 bar during the reac- tion, in order to produce the formate (7), and optionally producing the formic acid (11) from the formate.

2. The method according to claim 1, char acterized in that the bicarbonate solution (5) contains the bicarbonate and a solvent.

3. The method according to claim 2, char acterized in that the solvent of the bicar bonate solution (5) comprises water and ethanol.

4. The method according to any one of claims 1 to 3, characterized in that the carbon di oxide is captured, and the mixture (2) is formed.

5. The method according to any one of claims 1 to 4, characterized in that the carbon di oxide is captured from a gas (1) which comprises car- bon dioxide.

6. The method according to any one of claims 1 to 5, characterized in that the gas (1) comprising carbon dioxide is treated in at least one ejector stage for capturing the carbon dioxide wherein a motive medium is injected to at least one ejector of the ejector stage and the gas (1) is sucked into the same ejector in which the gas is mixed with the motive medium for forming a blend of the gas and motive medi um, and the mixture (2) is formed from the blend of the gas and motive medium or from a liquid phase of the blend.

7. The method according to any one of claims 1 to 6, characterized in that the carbonate, ammonia and/or hydroxide is added to the mixture (2).

8. The method according to any one of claims 1 to 7, characterized in that hydrogen, car bon monoxide, synthesis gas, gas comprising carbon monoxide and/or gas comprising carbon monoxide and hy drogen is supplied to the reactor (8).

9. The method according to any one of claims 1 to 8, characterized in that temperature is 15 - 50 °C during the reaction in the reactor (8).

10. The method according to any one of claims 1 to 9, characterized in that pressure is 20 - 60 bar during the reaction in the reactor (8).

11. The method according to any one of claims 1 to 10, characterized in that a strong acid (10) is added to the formate (7), and the formate is treated in order to form the formic acid (11).

12. The method according to claim 11, characterized in that a formed salt product produced as a by-product in the production of the for mic acid (11) is decomposed by a heat treatment or by heating back to a strong acid (10).

13. The method according to claim 12, characterized in that the formed strong acid is recycled to the production of the formic acid.

14. An apparatus for producing a formate or formic acid from carbon dioxide, character ized in that the apparatus comprises

- at least one equipment (4) into which a mixture (2) which comprises at least carbon dioxide and which further comprises carbonate, ammonia and/or hydroxide (3) is subjected for forming a bicar- bonate solution (5) comprising at least bicar bonate, and

- at least one reactor (8) in which the bicarbonate solution (5) is treated by a reaction with a met- al catalyst at temperature of 10 - 70 °C and pressure of 1 - 100 bar and at least one feeding device for supplying the hydrogen and/or carbon monoxide (6) into the reactor in order to produce the formate (7), and optionally to produce the formic acid (11) from the formate.

15. The apparatus according to claim 14, characterized in that the apparatus comprises at least one capture device (12) or ejector for cap turing the carbon dioxide.

16. A use of the method according to any one of claims 1 to 13, characterized in that the method is used in a production of formate, in a pro duction of formic acid, in a treatment of captured carbon dioxide, in a production of a chemical or liq- uid for using as a carrier of carbon dioxide and/or hydrogen, in a production of methanol, or their combi nations.