EP4547948A1

EP4547948A1 - Method for accumulating and producing energy associated with oxy-combustion without greenhouse gas emissions

Info

Publication number: EP4547948A1
Application number: EP23744555.6A
Authority: EP
Inventors: Matteo BERRA; Lorenzo BRUNO
Original assignee: Saipem SpA
Current assignee: Saipem SpA
Priority date: 2022-06-30
Filing date: 2023-06-30
Publication date: 2025-05-07
Anticipated expiration: 2043-06-30
Also published as: US20250270943A1; AU2023298394A1; CA3250499A1; IT202200013873A1; JP2025521633A; WO2024003857A1; EP4547948B1

Abstract

The present invention describes a method for producing, from electricity and available carbon dioxide, liquid carbon monoxide and liquid oxygen, to be subjected to oxy-combustion with production of carbon dioxide as a driving fluid.

Description

Method for accumulating and producing energy associated with oxy- combustion without greenhouse gas emissions

DESCRIPTION

There are multiple technologies for both the storage and the production of electricity .

As for the storage , the best known are : electrochemical (batteries ) , mechanical ( flywheels , compressed air, accumulation of water at high altitude ) , thermodynamic ( liquefied gases : liquid air, referred to as Liquid Air Energy Storage , LAES ) technologies .

Instead, as for the production of energy, it can be produced from a fuel by sequestering combustion CO2 , through carbon capture techniques from combustion fumes , or through combustion in a synthetic atmosphere mainly consisting of CO2 and oxygen, conducting an oxy-combustion, with which the fuel and oxygen are converted into CO2 and water and then removed from the system .

The oxy-combustion process is configured as an energy production system, possibly to be used to cover network demand peaks , but is not an energy accumulation system per se .

The oxy-combustion process requires the production of oxygen with a purity greater than 90% and this , in turn, entails the compression and puri fication of large amounts of air, most of which, once the oxygen is extracted, is simply released into the atmosphere .

The process of separating oxygen from air is also expensive , since in order to avoid compressing a much greater amount of air than that required to obtain oxygen therefrom, it requires sophisticated technical expedients which maximi ze the ef ficiency thereof .

Typically, oxy-combustion plants are heavily penali zed by the operations of extracting oxygen from the air and liquefying combustion CO2 .

To date , the most ef ficient oxy-combustion cycles with complete CO2 sequestration are the Allam cycle and the Graz cycle , which have an ef ficiency, calculated with respect to the lower calori fic value of the fuel and the energy invested in the production of the comburent (high purity oxygen) , equal to about 52 % .

It is also worth noting that the Allam cycle requires to cool the recirculation CO2 to a temperature not exceeding 16 ° C, which requires an adequate cold well , not always available in relation to the season, geographical position, and poss ibly the availability of a body of water .

Although the oxy-combustion cycles do not release combustion CO2 into the atmosphere , the problem of the permanent storage thereof remains : it is estimated that the spent hydrocarbon wells would not be enough to contain all the CO2 currently produced in a year .

For this reason, these technologies are not developed, also because they tend to move a problem over time , rather than solving it .

For its part , LAES has a considerable energy expenditure for the production of liquid air, which the inventors estimate at 0 . 45 kwh/ kg, and this strongly limits the amount of recoverable energy : in fact , a demonstrative plant of this type does not exceed an ef ficiency of 15% .

This is mainly due to the fact that among the fluids available for a condensation/evaporation cycle which does not require to store the gas , the air must reach low temperatures and therefore the amount of energy required for condensation is so high as to enhance the thermodynamic inef ficiencies of the process . Italian patent application IT 2020 0002 3167 ( Saipem S . p .A. ) describes the combination of an oxycombustion cycle with LAES energy accumulation technology .

International patent application WO 2021 /255578 (Energy Dome S . p .A. ) describes a plant for generating and accumulating energy, in which a closed thermodynamic cycle is integrated with oxy-combustion technology .

Patent application US 2019/211715 describes the separation of hydrogen and carbon monoxide from a gaseous fuel , a combustor supplied with carbon monoxide , and a carbon dioxide separation unit , for preparing carbon dioxide in the supercritical state .

Summary of the invention

The inventors of the present patent application have surprisingly developed a method which al lows storing available excess electricity in the form of liquid gases , in particular carbon monoxide and oxygen, to be then employed in an oxy-combustion cycle with energy production, integrating therebetween the technologies of oxy-combustion, dry carbon dioxide electrolysis , and energy storage in the form of frigories .

Obj ect of the invention In a first obj ect , the present invention describes a method for producing and accumulating energy, producing carbon monoxide and ultra-pure oxygen, as well as for using carbon dioxide .

In a second obj ect , the present invention describes a method for generating power .

The present invention globally describes a method for producing and accumulating energy, producing carbon monoxide and ultra-pure oxygen, as well as for using carbon dioxide and producing liquid carbon dioxide .

In a particular aspect , the method of the invention allows the management of energy peaks and deficiencies (peak shaving) .

Brief description of the drawings

Figure 1 shows the thermodynamic aspects of the process of the present invention .

Figure 2 depicts an embodiment of the accumulation step of the method of the present invention .

Figure 3 depicts an alternative embodiment of the accumulation step of the method of the present invention .

Figure 4 depicts an embodiment of the generation step of the method of the present invention . Figure 5 depicts an alternative embodiment o f the generation step of the method of the present invention .

Detailed description of the invention

For the purposes of the present invention, the heat exchanges conducted in the exchangers (El , E2 , E3 , E4 , En) are conducted with external fluids , preferably air, water, etc .

The heat exchangers ( indicated by "EXn" ) instead involve two flows inside the circuit ( s ) described in the invention .

In accordance with a first obj ect of the present invention, there is described a method for producing and accumulating energy, producing carbon monoxide and ultra-pure oxygen, as well as for using carbon dioxide .

Said carbon dioxide can be produced, for example , by industrial or refinery processes or even environmental processes , avoiding the release thereo f into the atmosphere .

The method of the present invention also allows managing energy peaks and deficiencies (peak shaving) . In particular, the energy accumulation is obtained by storing carbon monoxide and oxygen, at least partially liquefied, and a cooled fluid .

In particular, such a method comprises an accumulation step A) and a generation step B ) .

For the purposes of the present invention, the accumulation step A) is a step which allows producing a flow of carbon monoxide ( CO) and oxygen and possibly a cooled fluid .

In particular, in step A) the production of carbon monoxide ( CO) and oxygen is obtained by carbon dioxide electrolysis .

More in particular, such a step A) is conducted using excess electric current available in the network .

The term "available in excess" means an amount of electricity greater than that required .

According to an aspect of the invention, carbon monoxide and oxygen can be accumulated in the form of at least partially liquefied storages .

For the purposes of the present invention and with reference to the method depicted in figure 2 , step A) comprises the sub-steps of : Al ) electrolyzing an appropriately-heated carbon dioxide flow 3 and obtaining an initial carbon monoxide flow cl and an initial oxygen flow ol ,

A2 ) obtaining an at least partially liquefied carbon monoxide flow cl 7 from the initial carbon monoxide flow cl ,

A3 ) obtaining an at least partially liquefied oxygen flow ol O from the initial oxygen flow ol .

As for the electrolysis step Al ) , this is conducted in an electrolytic cell EL from an appropriately heated carbon dioxide flow 3 obtained from liquid carbon dioxide and possibly also from gaseous carbon dioxide .

In particular : in a step AOa ) , an initial liquid carbon dioxide flow 1 is withdrawn from a liquid carbon dioxide tank TCO21 and heated by heat exchange in a first sector of a first heat exchanger EXla, thus obtaining a heated carbon dioxide flow 2 , and in a step AOb ) , said heated carbon dioxide flow 2 is further heated by heat exchange in a second heat exchanger EX2 , thus obtaining said appropriately heated carbon dioxide flow 3 .

According to an aspect of the present invention, a step AOa' ) can be conducted, in which a second initial liquid carbon dioxide flow 1 ' ' is pumped in a pump P, thus obtaining a second pumped liquid carbon dioxide flow 2 ' ’ which is then heated by heat exchange in the first sector of a first heat exchanger EXla, thus obtaining a second heated carbon dioxide flow 3 ' ' , which can be stored in special storage wells .

According to an aspect of the present invention, a step AOb' ) can be conducted, in which an initial gaseous carbon dioxide flow 1 ' can be heated in the second heat exchanger EX2 , thus obtaining a heated gaseous carbon dioxide flow 2 ' , to be j oined to the suitable flow 3 .

According to an aspect of the present invention, the electrolytic cell EL is preferably a solid oxide cell ( SOEC ) .

As described above , two flows are obtained from step Al ) , namely :

- a flow, hereinafter referred to as the initial carbon monoxide flow cl , comprising carbon monoxide and carbon dioxide , and

- a flow, hereinafter referred to as the initial oxygen flow ol , comprising 99 . 9% pure oxygen .

According to a particular embodiment of the present invention, step Al ) can comprise producing power by exploiting the heat produced by Joule effect from the electrolytic cell, as will be described hereinafter .

As for the step A2 ) of obtaining an at least partially liquefied carbon monoxide flow cl3 from the initial carbon monoxide flow cl, this comprises the further sub-steps of:

A2a) obtaining a carbon monoxide flow to be purified c6,

A2b) obtaining a mainly carbon monoxide and vapor flow cl2, a recycled carbon monoxide flow ell, and a recirculation gas flow cr,

A2c) obtaining a dehydrated carbon monoxide flow cl3,

A2d) obtaining an at least partially liquefied carbon monoxide flow cl7.

In particular, step A2a) comprises the still further sub-steps of:

A2al) obtaining a first initial carbon monoxide flow portion c2 and a second initial carbon monoxide flow portion c2' ,

A2a2) cooling said first initial carbon monoxide flow portion c2 in a third heat exchanger EX3a, thus obtaining a first cooled initial carbon monoxide flow portion c3, A2a3 ) cooling said second initial carbon monoxide flow portion c2 ' in another third heat exchanger EX3b, thus obtaining a second cooled initial carbon monoxide flow portion c3 ' ,

A2a4 ) j oining said first cooled initial carbon monoxide flow portion c3 and said second cooled initial carbon monoxide flow portion c3 ' , thus obtaining a j oined cooled carbon monoxide flow c4 ,

A2a5 ) subj ecting said j oined cooled carbon monoxide flow c4 to compression in a first compressor cCl , thus obtaining a compressed carbon monoxide flow c5 , and to cooling in a first exchanger cEl , thus obtaining said carbon monoxide flow to be puri fied c6 .

For the purposes of the present invention, step A2a5 ) can possibly be repeated i f needed until the necessary conditions for the next step A3 ) are achieved .

Advantageously, step A2a5 ) allows an easier separation of carbon monoxide from carbon dioxide and improves the heat exchange profile in the carbon monoxide liquefaction process .

In an embodiment of the present invention, the initial carbon monoxide flow cl is not separated and is sent entirely to a third exchanger EX3 . For the purposes of the present invention, substep A2b) comprises the still further sub-steps of: A2bl) subjecting the carbon monoxide flow to be purified c6 to a first purification in a first purification column CL1 and obtaining a partially purified carbon monoxide flow c7, a physical solvent- released carbon monoxide flow c8, and a recycled carbon monoxide flow ell,

A2b2) subjecting the partially purified carbon monoxide flow c7 to a second purification in a second purification column CL2, thus obtaining a mainly carbon monoxide and vapor flow cl2, a flow to be regenerated m2, and a recirculation gas flow cr .

For the purposes of the present invention, the mainly carbon monoxide and vapor flow cl2 has a carbon dioxide concentration less than 500 ppm (mol/mol) and preferably less than 50 ppm (mol/mol) .

More in particular, said step A2bl) comprises the following steps: pl) washing with a physical solvent, p2) separation from the physical solvent, thus obtaining a regenerated physical solvent flow s9 and a physical solvent-separated flow c8, p3 ) compression and cooling, thus obtaining a physical solvent-separated compressed flow c9 and cooled cl O , p4 ) dehydration in a first Dehydration Unit cDUl , thus obtaining the recycled carbon monoxide flow cl 1 .

For the purposes of the present invention, the recycle flow el l referred to as the " recycled carbon monoxide flow" , comprises both carbon monoxide and carbon dioxide (which is intended for the electrolytic cell ) and is j oined to the appropriately heated carbon dioxide flow 3 originating the further appropriately heated carbon dioxide flow 3 ' to be sent to step Al ) described above .

More in particular, said step A2b2 ) comprises the following steps : pl ' ) expanding said flow to be regenerated m2 in an expander of the reaction product flow to be regenerated mEK, thus obtaining an expanded flow to be regenerated m3 , optionally with the production of power, p2 ' ) heating said expanded reaction product flow to be regenerated m3 in a heat exchanger of the reaction product flow to be regenerated mEXl , thus obtaining an expanded and heated reaction product flow to be regenerated m4 , which is sent to a regeneration column CL3 , p3 ' ) obtaining a basic aqueous flow m5 from the bottom of said regeneration column CL3 and a carbon dioxide and water flow hl , and obtaining a gaseous flow forming the recirculation gaseous flow cr therefrom .

For the purposes of the present invention, said recirculation gaseous flow cr is j oined to the physical solvent-released carbon monoxide flow c8 .

A flow can also be obtained from step p3 ' ) , which is intended for a reboiler of the third column (vEXl ) m8 , which must be heated, giving a heated flow exiting from the reboiler m9 , which in turn is sent back to the third column CL3 .

According to an embodiment of the present invention, such a reboiler vEXl is inside a Rankine cycle , as described hereinbelow .

For the purposes of the present invention, step A2c ) comprises the step of subj ecting the mainly carbon monoxide and vapor flow cl2 to a dehydration step in a second Dehydration Unit cDU2 , thus obtaining a dehydrated carbon monoxide flow cl3 .

The second Dehydration Unit preferably operates by means of molecular sieves . For the purposes of the present invention, step A2d) comprises the still further sub-steps of:

A2dl) subjecting said dehydrated carbon monoxide flow cl3 to a first cooling step, thus obtaining a partially cooled dehydrated carbon monoxide flow cl4,

A2d2) subjecting said partially cooled dehydrated carbon monoxide flow cl4 to a second cooling step, thus obtaining a cooled dehydrated carbon monoxide flow cl5,

A2d3) subjecting said cooled dehydrated carbon monoxide flow cl5 to a third cooling step, thus obtaining a further cooled dehydrated carbon monoxide flow cl6,

A2d4) expanding said further cooled dehydrated carbon monoxide flow cl6 by expansion in a first expander cEKl, possibly with the production of power, thus obtaining an at least partially liquefied carbon monoxide flow cl7, which can then be stored in a liquid carbon monoxide tank TCO1.

For the purposes of the present invention, the first cooling step A2dl) is conducted in a first section of a first heat exchanger EXla.

For the purposes of the present invention, the second cooling step A2d2) is conducted in a second section of a first heat exchanger EXlb. For the purposes of the present invention, the third cooling step A2d3 ) is conducted in a third section of a first heat exchanger EXlc .

The heat exchanges of step A2d) are conducted by heat exchange also with a refrigerant circulating in a refrigerant circuit , as will be described hereinafter .

As described above , an initial oxygen flow ol is also obtained from the electrolysis step Al ) , from which, in accordance with step A3 ) , an at least partially liquefied oxygen flow ol O is obtained .

For the purposes of the present invention, said step A3 ) comprises the further sub-steps of :

A3a ) obtaining a first initial oxygen flow portion o2 and a second initial oxygen flow portion o2 ' ,

A3b ) cooling said first initial oxygen flow portion o2 in a third heat exchanger EX3a, thus obtaining a first cooled initial oxygen flow portion o3 ,

A3c ) cooling said second initial oxygen flow portion o2 ' in another third heat exchanger EX3b, thus obtaining a second cooled initial oxygen flow portion o3 ' , A3d) joining said first cooled initial oxygen flow portion o3 and said second cooled initial oxygen flow portion o3' , thus obtaining a joined cooled oxygen flow o4,

A3e) subjecting said joined cooled oxygen flow o4 to compression in an oxygen compressor oCl, thus obtaining a compressed oxygen flow o5 and to cooling in an oxygen exchanger oE, thus obtaining said compressed and cooled oxygen flow 06,

A3f) subjecting said compressed and cooled oxygen flow 06 to cooling, thus obtaining an at least partially liquefied oxygen flow olO, which can then be stored in a liquid oxygen tank T021.

For the purposes of the present invention, said step A3f) comprises the still further steps of:

A3fl) subjecting said compressed and cooled oxygen flow 06 to a first cooling step, thus obtaining an oxygen flow at a further first cooling level o7,

A3f2) subjecting said oxygen flow at a further first cooling level o7 to a second cooling step, thus obtaining an oxygen flow at a further second cooling level 08,

A3f3) subjecting said oxygen flow at a further second cooling level 08 to a third cooling step, thus obtaining an oxygen flow at a further third cooling level o9,

A3f4) expanding said oxygen flow at a further third cooling level o9 to expansion in a first oxygen expander oEKl, possibly with the production of power, thus obtaining an at least partially liquefied oxygen flow olO stored in a liquid oxygen tank T021.

In an embodiment of the present invention, the initial oxygen flow 01 is not separated and is sent entirely to a third exchanger EX3.

For the purposes of the present invention, step A3e) can possibly be repeated if needed until the necessary conditions for the next step A3f) are obtained .

For the purposes of the present invention, the first cooling step A3fl) is conducted in a first section of a first heat exchanger EXla.

For the purposes of the present invention, the second cooling step A3f2) is conducted in a second section of a first heat exchanger EXlb.

For the purposes of the present invention, the third cooling step A3f3) is conducted in a third section of a first heat exchanger EXlc. The heat exchanges of steps A3b) and A3c) are also conducted by heat exchange with a refrigerant fluid outside the process, such as air or water.

According to a preferred embodiment, the heat exchanges of steps A3b) and A3c) are conducted by heat exchange with a flow circulating and operating in a Rankine cycle, as will be described hereinafter.

The heat exchanges of step A3f) are also conducted by heat exchange with a refrigerant fluid circulating in a refrigerant fluid cycle, as will be described hereinafter.

According to an aspect of the present invention, said refrigerant fluid can be hydrogen, helium, or nitrogen .

In particular, said refrigerant fluid circuit comprises a first refrigerant fluid flow fl which is subjected to the steps of:

I) cooling, thus obtaining a second refrigerant fluid flow f2,

II) further cooling in a first refrigerant fluid exchanger fEl, thus obtaining a third refrigerant fluid flow f3,

III) a first heat exchange step with which said third refrigerant fluid flow f3 is cooled, thus obtaining a fourth flow f4, IV) a second heat exchange step with which said fourth refrigerant fluid flow f4 is cooled, thus obtaining a fifth flow f5,

V) a third heat exchange step with which said fifth refrigerant fluid flow f5 is cooled, thus obtaining a sixth flow f6,

VI) expansion in a first refrigerant fluid expander fEKl, thus obtaining a seventh refrigerant fluid flow f7, possibly with the production of power,

VII) a first heat exchange step with which said seventh refrigerant fluid flow f7 is heated, thus obtaining an eighth flow f8,

VIII) a second heat exchange step with which said eighth refrigerant fluid flow f8 is heated, thus obtaining a ninth flow f9,

IX) a third heat exchange step with which said ninth refrigerant fluid flow f9 is heated, thus obtaining a tenth flow flO,

X) compression of said tenth flow flO, thus obtaining an eleventh flow fll which is cooled in a first refrigerant fluid exchanger fEl, thus obtaining a twelfth flow fl2,

XI) compression of said twelfth flow fl2 by means of a second compression of the refrigerant fluid fC2, thus obtaining the first flow fl. For the purposes of the present invention, step X) can be repeated one or more times, if needed.

According to an embodiment of the invention, a refrigerant fluid flow portion referred to as a further fourth flow f4' is obtained from the fourth flow f4, which is expanded in a second refrigerant fluid expander fEK2, thus obtaining a further fifth flow f5' , which is subjected to a heat exchange step VIII*) (similarly to the steps described above) , thus obtaining a further sixth flow f6' , which is further heated in a heat exchange step IX*) , thus obtaining a further seventh flow f7' , which is then joined to the tenth refrigerant fluid flow flO.

For the purposes of the present invention, cooling step I) is conducted by heat exchange in the second heat exchanger EX2.

For the purposes of the present invention, cooling step III) , heating step IX) and heating step IX*) are conducted by heat exchange in the first section of a first heat exchanger EXla.

For the purposes of the present invention, cooling step IV) , step VIII) and step VIII*) are conducted by heat exchange in the second section of a first heat exchanger EXlb. For the purposes of the present invention, the cooling step V) and the heating step VII) are conducted by heat exchange in the third section of a first heat exchanger EXlc.

As described above, in a particular embodiment of the present invention, step Al) can comprise a step Al' ) for producing power by exploiting the heat produced by Joule effect from the electrolytic cell.

More in particular, said step Al' ) comprises heating a fluid by heat exchange with the initial carbon monoxide flow cl or with a portion thereof c2, c2' and/or by heat exchange with the initial oxygen flow ol or with a portion o2,o2' thereof.

After each heating step, the heated fluid is subjected to expansion with production of power.

For the purposes of the present invention, said step Al' ) can be a step inside a Rankine cycle.

In an embodiment of the invention, said Rankine cycle is a water vapor cycle.

In a particular embodiment of the present invention, said Rankine cycle comprises subjecting a first vapor flow vl to the steps of:

Rl) heating, thus obtaining a second vapor flow v2 , R2 ) expansion of said second vapor flow in a first expander of the Rankine cycle vEKl with the production of power, thus obtaining a third vapor flow v3 ,

R3 ) further heating, thus obtaining a fourth vapor flow v4 ,

R4 ) further expansion in a second expander of the Rankine cycle , thus obtaining a fi fth vapor flow v5 ,

R5 ) cooling in a first exchanger of the Rankine cycle vEl , thus obtaining a sixth condensed vapor flow v6 ,

R6 ) pumping in a first pump of the Rankine cycle vPl , thus obtaining a seventh condensed vapor f low v7 , which is subj ected to step

R7 ) further pumping in a second pump of the Rankine cycle vP2 , thus obtaining the first vapor flow vl .

For the purposes of the present invention, from the second expander of the Rankine cycle vEK2 , a further fi fth vapor flow v5 ' is further obtained, which is cooled in a particular exchanger of the Rankine cycle vEXl , giving a further sixth vapor flow v6 ' (which is in fact a condensed vapor flow) , which is further cooled in a second exchanger of the Rankine cycle vE2 , thus obtaining a further seventh condensed vapor flow v7 ' , which is j oined to the seventh flow v7 before being sent to the second pump vP2 .

For the purposes of the present invention, step Rl ) is conducted by heat exchange with the second portion of the initial oxygen flow o2 ' and with the second portion of the initial carbon monoxide flow c2 ' inside the other third heat exchanger EX3b .

For the purposes of the present invention, step R3 ) is conducted by heat exchange with the first portion of the initial oxygen flow o2 and with the first portion of the initial carbon dioxide/carbon monoxide mixture flow c2 inside the third heat exchanger EX3a .

As for the particular exchanger of the Rankine cycle vEXl , it is the boiler of the third column (vEl ) : it heats and partially vapori zes m8 , as described above .

A particular embodiment of step A2bl ) is described below, with which a partially puri fied carbon monoxide flow c7 , a physical solvent-released carbon monoxide flow c8 , and a recycled carbon monoxide flow el l are obtained . In particular, inside the first column CL1 , an initial physical solvent flow s i encounters the carbon monoxide flow to be puri fied c6 in countercurrent , thus obtaining the partially puri fied carbon monoxide flow c7 from the head of the column CL1 .

A physical solvent and carbon dioxide flow s2 is obtained from the bottom of the column CL1 , comprising an amount of carbon monoxide , which is expanded in a first physical solvent expander sEKl , possibly with the production of power, thus obtaining an expanded physical solvent , carbon monoxide and carbon dioxide flow s3 .

The expanded physical solvent , carbon monoxide and carbon dioxide flow s3 releases the carbon monoxide and part of the carbon dioxide inside the solvent separator sS and the solvent column sC by virtue of a regenerated physical solvent washing flow s l2 ; a separate physical solvent flow s7 ( liquid) and a main carbon monoxide flow s4 ( gaseous ) are thus obtained .

Said main carbon monoxide flow 4 is compressed in a first compressed solvent sCl , thus obtaining a main compressed carbon monoxide flow s5 , which is cooled in a f irst solvent exchanger sEl , thus obtaining a main carbon monoxide return flow to the first column s6.

As for the separate physical solvent flow s7, this is expanded in a second solvent expander sEK2, thus obtaining a separate physical solvent flow s8, which is sent to a first separator SI, from which the physical solvent-released carbon monoxide flow c8 described above and a partially regenerated physical solvent flow s9 are obtained.

Said partially regenerated physical solvent flow is pumped by a first solvent pump sPl, thus obtaining a pumped partially regenerated solvent flow slO, which is heated in a first solvent exchanger sEl, thus obtaining a regenerated physical solvent flow at room temperature, of which a first portion sl2 is sent to the solvent column sC as regenerated physical solvent and a second portion sl3 is pumped by a second solvent pump sP2, thus obtaining the initial physical solvent flow si.

For the purposes of the present invention, the physical solvent involved in the purification steps in the first column CL1 can be Selexol, Rectisol, Methanol, etc.

A particular embodiment of step A2b2) is described hereinbelow, with which a mainly carbon monoxide and vapor flow cl2 , a flow to be regenerated m2 and a gaseous recirculation flow cr are obtained .

In particular, inside the second column CL2 , the partially puri fied carbon monoxide flow (which is in gaseous form) obtained from the head of the first column CL1 encounters a basic ( l iquid) solution flow ml in countercurrent .

For the purposes of the present invention, a basic solution can be an aqueous solution of an amine , such as methylethylamine (MEA) or a sodium bicarbonate solution .

A reaction product solution flow m2 is thus obtained from the bottom of the second column CL2 , which is expanded in an expander of the reaction product flow to be regenerated mEK, thus obtaining an expanded reaction product solution to be regenerated m3 , then heated by heat exchange in a basic solution heat exchanger mEXl , thus obtaining an expanded and heated reaction product flow to be regenerated m4 .

Said expanded and heated reaction product flow to be regenerated m4 is sent to the regeneration column CL3 , from which a basic bottom flow m5 and a head carbon dioxide and water flow hl are obtained .

As for the basic bottom flow m5 , this is cooled by heat exchange inside the basic solution heat exchanger mEXl , thus obtaining a cooled basic bottom flow m6 , which i s pumped by a basic bottom flow pump mP obtaining a cooled and pumped basic bottom flow m7 and further cooled in a basic solution exchanger mE , thus obtaining the liquid basic solution ml .

The head carbon dioxide and water flow hl is cooled in a regeneration column exchanger hE , thus obtaining a carbon dioxide and partially condensed water flow h2 , from which, inside a regeneration column separator hS , a bottom liquid flow h3 is obtained .

After possibly refilling the bottom liquid flow h3 with a water flow (make-up water in the figures ) , this is pumped by a regeneration column pump hP, giving a pumped reflux flow h4 of regeneration column sent to the head of the column CL3 .

From the separator head of the regeneration column, instead, a gaseous recirculation flow cr is obtained, which is j oined to the physical solvent- released carbon monoxide flow c8 , as described above .

According to an alternative embodiment of the present invention depicted in figure 3 , for example , after having obtained an at least partially liquefied carbon monoxide flow cl 7 with step A2d4 ) , this is subj ected to the further steps described below . In particular, in a first separator cS l , a first liquid bottom flow cl 8 and a first gaseous head flow c24 are separated from the at least partially liquefied carbon monoxide flow cl 7 .

The first liquid bottom flow cl 8 is expanded by means of an expansion valve eV, giving a first expanded gaseous bottom flow cl 9 , from which a second liquid bottom flow c20 , which is stored in a liquid carbon monoxide tank cTCOl , and a second gaseous head flow c21 , are separated in a second separator cS2 .

The second gaseous head flow c21 is compressed in a third carbon monoxide compressor cC3 to obtain a second compressed gaseous head flow c22 , which is cooled in a third carbon monoxide exchanger cE3 to obtain a second compressed and cooled head flow c23 , which is j oined to the dehydrated carbon monoxide flow cl 3 .

In particular, the compression and cooling described above can be repeated one or more times , i f needed .

As for the first gaseous head flow c24 , this is subj ected to a heating step A2e ) , comprising the further sub-steps of :

A2el ) first heating, thus obtaining a first gaseous head flow at a first heating level c25, A2e2 ) second heating, thus obtaining a second gaseous head flow at a first heating level c26,

A2e3 ) third heating, thus obtaining a second gaseous head flow at a third heating level c27 , which is j oined to the second gaseous head flow c21 .

For the purposes of the present invention, step A2el ) is conducted in the third section of the f irst heat exchanger EXlc .

For the purposes of the present invention, step A2e2 ) is conducted in the second section of the first heat exchanger EXlb .

For the purposes of the present invention, step A2e3 ) is conducted in the first section of the first heat exchanger EXla

According to an alternative embodiment of the present invention, after obtaining an at least partially liquefied oxygen flow ol O with step A3 f ) , this is subj ected to the further steps described below .

In particular, a first liquid bottom flow oi l and a first gaseous head flow ol 7 are separated from the at least partially liquefied oxygen flow ol O in a first separator oS l .

The first liquid bottom flow oi l is expanded by means of an expansion valve oV, giving a first expanded gaseous bottom flow ol2, from which a second liquid bottom flow ol3, which is stored in a liquid oxygen tank cTO21, and a second gaseous head flow ol4, are separated in a second separator oS2.

The second gaseous head flow ol4 is compressed in a second oxygen compressor oC2, thus obtaining a second compressed gaseous head flow ol5, which is cooled in a second oxygen exchanger oE2, thus obtaining a second compressed and cooled head flow 0I6, which is joined to the compressed and cooled oxygen flow 06.

In particular, the compression and cooling described above can be repeated one or more times, if needed .

As for the first gaseous head flow oil, this is subjected to a heating step A3g) , comprising the further sub-steps of:

A3gl) first heating, thus obtaining a first gaseous head flow at a first heating level 0I8,

A3g2) second heating, thus obtaining a first gaseous head flow at a second heating level ol9,

A3g3) third heating, thus obtaining a first gaseous head flow at a third heating level o20, which is joined to the second gaseous head flow ol4. For the purposes of the present invention, step A3gl) is conducted in the third section of the first heat exchanger EXlc.

For the purposes of the present invention, step A3g2) is conducted in the second section of the first heat exchanger EXlb.

For the purposes of the present invention, step A3g3) is conducted in the first section of the first heat exchanger EXla.

In particular, the heat exchanges of step A2e) and A3g) are also conducted by heat exchange with a refrigerant fluid circulating in another refrigerant fluid circuit, as will be described hereinafter.

In particular, said other refrigerant fluid circuit comprises another first refrigerant fluid flow f ’ 1 which is subjected to the steps of:

I' ) cooling, thus obtaining another second refrigerant fluid flow f'2,

II' ) further cooling in another first refrigerant fluid exchanger f'El, thus obtaining another third refrigerant fluid flow f'3,

III' ) a first heat exchange step with which said another third refrigerant fluid flow f ’ 3 is cooled, thus obtaining another fourth flow f'4, IV' ) a second heat exchange step with which said another fourth refrigerant fluid flow f ' 4 is cooled, thus obtaining another fifth flow f'5,

V' ) a third heat exchange step with which said another fifth refrigerant fluid flow f'5 is cooled, thus obtaining another sixth flow f ' 6,

VI' ) expansion in another first refrigerant fluid expander f'EKl, thus obtaining another seventh refrigerant fluid flow f' 7 , possibly with the production of power,

VII' ) a first heat exchange step with which said another seventh refrigerant fluid flow f ' 7 is heated, thus obtaining another eighth flow f'8,

VIII' ) a second heat exchange step with which said another eighth refrigerant fluid flow f ' 8 is heated, thus obtaining another ninth flow f ' 9,

IX' ) a third heat exchange step with which said another ninth refrigerant fluid flow f ' 9 is heated, thus obtaining another tenth flow f'10,

X' ) compression of said another tenth flow f'10, thus obtaining another eleventh flow f'll which is cooled in another first refrigerant fluid exchanger f'El obtaining another twelfth flow f'12,

XI' ) compression of said other twelfth flow f ' 12 by means of another second compressor of the refrigerant fluid f'C2, thus obtaining said another first flow f ' 1.

For the purposes of the present invention, step X' ) can be repeated one or more times, if needed.

According to an embodiment of the invention, another refrigerant fluid flow portion referred to as another further fourth flow f'4' is obtained from the another fourth flow f'4, which is expanded in another second refrigerant fluid expander f'EK2, thus obtaining another further fifth flow f'5' , which is subjected to a heat exchange step VIII*' ) (similarly to the step described above) , thus obtaining another further sixth flow f ' 6' , which is further heated in a step IX*' ) (similarly to the step described above) , thus obtaining another further seventh flow f 7' , which is then joined to the another ninth refrigerant fluid flow f 9 ' .

For the purposes of the present invention, the cooling step I' ) is conducted by heat exchange in the second heat exchanger EX2.

For the purposes of the present invention, the cooling step III' ) , heating step IX' ) and heating step IX*' ) are conducted by heat exchange in the first section of a first heat exchanger EXla. For the purposes of the present invention, the cooling step IV' ) and the heating step VIII' ) and the heating step VIII*' ) are conducted by heat exchange in the second section of a first heat exchanger EXlb.

For the purposes of the present invention, the cooling step V' ) and the heating step VII' ) are conducted by heat exchange in the third section of a first heat exchanger EXlc.

In accordance with a second object of the present invention, a method for generating power is described .

For the purposes of the present invention, said generation step B) comprises the sub-steps of:

Bl) obtaining a combustion gas flow el from a gaseous oxygen flow to be sent to the combustor a4 and from a gaseous carbon monoxide flow to be sent to the combustor b4,

B2) expanding said combustion gas flow el in a combustion gas expander eEKl with power generation, thus obtaining an expanded combustion gas e2,

B3) cooling said combustion gas flow e2 to obtain an expanded and cooled combustion gas flow e3,

B4) dehydrating said expanded and cooled combustion gas flow e3 and obtaining a dehydrated combustion gas flow e5, B5 ) separating a first dehydrated combustion gas flow portion e5 ' and obtaining a dehydrated and further cooled combustion gas first flow portion e5 ' ’ , which is sent to a liquid carbon dioxide tank aTCO21 ,

B6 ) cooling the remaining portion of said dehydrated combustion gas flow e5 , thus obtaining a dehydrated and cooled combustion gas flow e 6 , which is in liquid form,

B7 ) pumping said condensed combustion gas flow e 6 in a combustion gas pump eP, thus obtaining a condensed and pumped combustion gas flow e7 ,

B8 ) heating said condensed and pumped combustion gas flow e7 , thus obtaining a pumped and heated combustion gas e8 , which i s sent to the combustor for step Bl ) .

For the purposes of the present invention, said gaseous oxygen flow to be sent to the combustor a4 is obtained from a liquid oxygen flow al withdrawn from a liquid oxygen tank aTO21 , which is subj ected to the steps :

BOa ) of pumping by means of a liquid oxygen pump aP, thus obtaining a pumped liquid oxygen flow a2 , BOb) subjecting said pumped oxygen flow a2 to a first heating, thus obtaining a partially heated oxygen flow a3,

BOc) subjecting said partially heated oxygen flow a3 to a second heating, thus obtaining a vaporized oxygen flow a4, which is sent to a combustor CC for step Bl) .

For the purposes of the present invention, said gaseous carbon monoxide flow b4 to be sent to the combustor is obtained from a liquid carbon monoxide flow bl withdrawn from a carbon monoxide tank aTCOl, which is subjected to the steps of:

BO' a) pumping by means of a liquid carbon monoxide pump bP, thus obtaining a pumped liquid carbon monoxide flow b2,

BO'b) subjecting said pumped carbon monoxide flow b2 to a first heating, thus obtaining a partially heated carbon monoxide flow b3,

BO'c) subjecting said partially heated carbon monoxide flow b3 to a second heating, thus obtaining a vaporized carbon monoxide flow b4, which is sent to the combustor CC for step Bl) .

In particular, said steps BOb) and BO'b) are conducted by heat exchange inside a first oxygen and carbon monoxide heat exchanger eEXl . In particular, said steps BOc ) and BO ' c ) are conducted by heat exchange inside a second oxygen and carbon monoxide heat exchanger eEX2 .

For the purposes of the present invention, a dehydrated and cooled combustion gas flow portion e 6 ' is separated from the dehydrated and cooled combustion gas flow e 6 obtained from step B6 ) , which is sent to the liquid carbon dioxide tank aTCO21 .

For the purposes of the present invention, step B4 ) comprises the further sub-steps of :

B4a ) separating a first water portion eWl in a combustion gas separator eS , thus obtaining a partially dehydrated combustion gas flow e4 ,

B4b ) dehydrating the partial ly dehydrated combustion gas flow e4 in a combustion gas Dehydration Unit eDU, thus obtaining the dehydrated combustion gas flow e5 .

For the purposes of the present invention, the cooling step B5 ) is conducted by heat exchange inside the first oxygen and carbon monoxide heat exchanger eEXl .

For the purposes of the present invention, steps B3 ) and B8 ) described above are conducted by heat exchange inside the second oxygen and carbon monoxide heat exchanger eEX2 . As for step B6 ) , this is conducted in a refrigerant fluid heat exchanger EXfr .

In particular, a first refrigerant fluid flow arf l is withdrawn from a refrigerant fluid tank aTrf l , which is heated by heat exchange with the dehydrated combustion gas flow e5 , thus obtaining a second cooled fluid flow arf2 , which is stored in a second refrigerant fluid tank aTrf2 .

For the purposes of the present invention, the refrigerant fluid employed in step B6 ) is a storage refrigerant fluid, which can be glycol or an aqueous glycol solution .

According to a particular embodiment of the present invention, an additional flow F consisting of carbon dioxide and hydrocarbons , for example methane , or consisting of carbon monoxide produced, for example , by the gasi fication of coal or as a refinery residue , can further be sent to step Bl ) .

According to an alternative embodiment of the present invention, for example shown in figure 5 , in step B2 ) the combustion gas flow el ) is expanded in a two-stage expansion machine ; thereby, a first expanded combustion flow portion e2 is obtained, which is then subj ected to the further steps described above . From the second expansion stage, a fully expanded combustion gas flow el2 (referred to as the second expanded combustion gas flow) is instead obtained, which is subjected to the further steps of:

B9) cooling, thus obtaining a second cooled expanded combustion gas flow el3,

BIO) cooling in a fourth heat exchanger EX4, thus obtaining a second further-cooled expanded combustion gas flow el4,

Bll) separating a second water portion eW2, thus obtaining a second dehydrated combustion gas flow el5,

B12) compressing said second dehydrated combustion gas flow el5 in a combustion gas compressor, thus obtaining a second compressed combustion gas flow el6,

B13) heating the second compressed combustion gas flow el6, thus obtaining a second compressed and heated combustion gas flow el7,

B14) further heating the second compressed and heated combustion gas flow el7, thus obtaining a second compressed and further-heated combustion gas flow el 8.

For the purposes of the present invention, steps B9) and B13) are both conducted in a third heat exchanger EX3 by heat exchange between the fully expanded combustion gas flow el2 and the second compressed combustion gas flow el6 in countercurrent.

As for step BIO) , this is instead conducted inside a fourth heat exchanger EX4, described below.

For the purposes of the present invention, from the condensed and pumped combustion gas flow e7 obtained from step B7) a portion e9 (to be referred to as the second condensed and pumped combustion gas flow) is separated, which is subjected to the further steps of:

B15) heating, thus obtaining a second condensed and pumped heated combustion gas flow elO,

B16) further heating, thus obtaining a second condensed and pumped further-heated combustion gas flow ell.

For the purposes of the present invention, step B15) is conducted in the fourth heat exchanger EX4 by heat exchange with the cooled expanded combustion gas flow el3.

For the purposes of the present invention, step B16) is conducted in the second heat exchanger eEX2.

According to the present embodiment, the three flows represented by:

- pumped and heated combustion gas flow e8, second further-heated condensed and pumped combustion gas flow el l and

- compressed and further-heated combustion gas flow el 8 are j oined in a single flow el 9 which is returned to the combustor for step Bl ) .

For the purposes of the present invention, the flows of liquid carbon monoxide bl and liquid oxygen al employed in the generation step ( step B ) ) are obtained from tanks aTCOI , aTO2 I in which a flow of liquid carbon monoxide c20 and a flow of liquid oxygen ol 3 obtained according to the method of the accumulation step A) of the present invention and indicated above by cTCOI and cTO2 I , respectively, are stored .

In accordance with another obj ect , the present invention describes a method for producing and accumulating energy, producing carbon monoxide and ultra-pure oxygen, as well as for using carbon dioxide and producing liquid carbon dioxide .

Therefore , the present invention globally describes the following points : Point 1 : A method for producing and accumulating energy, producing carbon monoxide and oxygen, and using carbon dioxide , comprising an accumulation step A) and a generation step B ) , where said accumulation step A) allows producing a carbon monoxide flow ( CO) and an oxygen flow and possibly a refrigerated fluid . Point 2 : The method according to the preceding point , where said step A) comprises the sub-steps of :

Al ) electrolyzing an appropriately-heated carbon dioxide flow 3 and obtaining an initial carbon monoxide flow cl and an initial oxygen flow ol ,

Point 3 : The method according to the preceding point , where said step A2 ) comprises the further sub-steps of :

A2a ) obtaining a carbon monoxide flow to be puri fied c6 ,

A2b ) obtaining a mainly carbon monoxide and vapor flow cl2 , a recycled carbon monoxide flow el l , and a recirculation gas flow cr, A2c) obtaining a dehydrated carbon monoxide flow c!3,

A2d) obtaining an at least partially liquefied carbon monoxide flow cl7.

Point 4: The method according to the preceding point, where said step A2a) comprises the further sub-steps of :

A2a2) cooling said first initial carbon monoxide flow portion c2 in a third heat exchanger EX3a, thus obtaining a first cooled initial carbon monoxide flow portion c3,

A2a3) cooling said second initial carbon monoxide flow portion c2' in another third heat exchanger EX3b, thus obtaining a second cooled initial carbon monoxide flow portion c3' ,

A2a4) joining said first cooled initial carbon monoxide flow portion c3 and said second cooled initial carbon monoxide flow portion c3' , thus obtaining a joined cooled carbon monoxide flow c4,

A2a5) subjecting said joined cooled carbon monoxide flow c4 to compression in a first compressor cCl, thus obtaining a compressed carbon monoxide flow c5, and to cooling in a first exchanger cEl, thus obtaining said carbon monoxide flow to be purified c6.

Point 5: The method according to the preceding point, where the heat exchanges of steps A2a2) and A2a3) are conducted by heat exchange with a flow circulating and operating in a Rankine cycle.

Point 6: The method according to the preceding point, where said sub-step A2b) comprises the still further sub-steps of:

A2bl) subjecting the carbon monoxide flow to be purified c6 to a first purification in a first purification column CL1 and obtaining a partially purified carbon monoxide flow c7, a physical solvent- released carbon monoxide flow c8, and a recycled carbon monoxide flow ell,

A2b2) subjecting the partially purified carbon monoxide flow c7 to a second purification in a second purification column CL2, thus obtaining a mainly carbon monoxide and vapor flow cl2, a flow to be regenerated m2, and a recirculation gas flow cr . Point 7: The method according to the preceding point, where said sub-step A2bl) comprises the following steps : pl) washing with a physical solvent, p2) separation from the physical solvent, thus obtaining a regenerated physical solvent flow s9 and a physical solvent-separated flow c8, p3) compression and cooling, thus obtaining a physical solvent-separated compressed flow c9 and cooled clO, p4) dehydration in a first Dehydration Unit cDUl, thus obtaining the recycled carbon monoxide flow cl 1. Point 8: The method according to the preceding point, where said recycled carbon monoxide flow ell is joined to the appropriately-heated carbon monoxide flow 3, originating the further appropriately-heated carbon monoxide flow 3' to be sent to step Al) .

Point 9: The method according to point 6, where said step A2b2) comprises the following steps: pl' ) expanding said flow to be regenerated m2 in an expander of the reaction product flow to be regenerated mEK, thus obtaining an expanded flow to be regenerated m3, optionally with the production of power, p2' ) heating said expanded reaction product flow to be regenerated m3 in a heat exchanger of the reaction product flow to be regenerated mEXl, thus obtaining an expanded and heated reaction product flow to be regenerated m4, which is sent to a regeneration column CL3, p3' ) obtaining a basic aqueous flow m5 from the bottom of said regeneration column CL3 and a carbon dioxide and water flow hl from the head, and obtaining a gaseous flow forming the recirculation gaseous flow cr therefrom. Point 10: The method according to the preceding point, where said recirculation gas flow cr is joined to the physical solvent-released carbon monoxide flow c8.

Point 11: The method according to point 9, where a flow can also be obtained from said step p3' ) , which is intended for a reboiler of the third column (vEXl) m8, which is heated, giving rise to a heated flow exiting from the reboiler m9, which in turn is sent back to the regeneration column CL3.

Point 12: The method according to point 3, where said step A2d) comprises the still further sub-steps of:

Point 13: The method according to point 3, where the heat exchanges of step A2d) are conducted by heat exchange also with a refrigerant circulating in a refrigerant circuit.

Point 14: The method according to point 2, where said step A3) comprises the further sub-steps of:

A3a) obtaining a first initial oxygen flow portion o2 and a second initial oxygen flow portion o2' ,

A3b) cooling said first initial oxygen flow portion o2 in a third heat exchanger EX3a, thus obtaining a first cooled initial oxygen flow portion o3, A3c) cooling said second initial oxygen flow portion o2' in another third heat exchanger EX3b, thus obtaining a second cooled initial oxygen flow portion o3' ,

A3d) joining said first cooled initial oxygen flow portion o3 and said second cooled initial oxygen flow portion o3' , thus obtaining a joined cooled oxygen flow o4,

A3e) subjecting said joined cooled oxygen flow o4 to compression in an oxygen compressor oCl, thus obtaining a compressed oxygen flow o5 and to cooling in an oxygen exchanger oEl, thus obtaining said compressed and cooled oxygen flow 06,

Point 15: The method according to the preceding point, where the heat exchanges of steps A3b) and A3c) are conducted by heat exchange with a flow circulating and operating in a Rankine cycle.

Point 16: The method according to the preceding point, where the heat exchanges of step A3f) are conducted by heat exchange also with a refrigerant fluid circulating in a refrigerant fluid cycle. Point 17 : The method according to the preceding step, where said refrigerant fluid is hydrogen, helium, or nitrogen .

Point 18 : The method according to point 9 , where said gaseous recirculation flow cr is j oined to the physical solvent-released carbon monoxide flow c8 .

Point 19 : The method according to any one of the preceding points , where said step A) is conducted by using excess electric current available in the network .

Point 20 : The method according to any one of the preceding points , where said generating step B ) comprises the sub-steps of :

Bl ) obtaining a combustion gas flow el from a gaseous oxygen flow a4 sent to the combustor and from a gaseous carbon monoxide flow b4 sent to the combustor,

B2 ) expanding said combustion gas flow el in a combustion gas expander eEKl with power generation, thus obtaining an expanded combustion gas e2 ,

B3 ) cooling said combustion gas flow e2 to obtain an expanded and cooled combustion gas flow e3 ,

B4 ) dehydrating said expanded and cooled combustion gas flow e3 and obtaining a dehydrated combustion gas flow e5 , B5) separating a first dehydrated combustion gas flow portion e5' and obtaining a dehydrated and further cooled combustion gas first flow portion e5' ’ , which is sent to a liquid carbon dioxide tank aTCO21,

B6) cooling the remaining portion of said dehydrated combustion gas flow e5, thus obtaining a dehydrated and cooled combustion gas flow e6, which is in liquid form,

B7) pumping said condensed combustion gas flow e6 in a combustion gas pump eP, thus obtaining a condensed and pumped combustion gas flow e7,

B8) heating said condensed and pumped combustion gas flow e7, thus obtaining a pumped and heated combustion gas e8, which is sent to the combustor for step Bl ) .

Point 21: The method according to the preceding point, where in said step B6) a portion of the dehydrated and cooled combustion gas flow e6' is separated, which is sent to the liquid carbon dioxide tank aTCO21.

Point 22: The method according to point 20 or 21, where step B4) comprises the further sub-steps of: B4a) separating a first water portion eWl in a combustion gas separator eSl, thus obtaining a partially dehydrated combustion gas flow e4,

B4b) dehydrating the partially dehydrated combustion gas flow e4 in a combustion gas Dehydration Unit eDU, thus obtaining the dehydrated combustion gas flow e5. Point 23: The method according to the preceding point, where said cooling step B5) is conducted by heat exchange inside the first oxygen and carbon monoxide heat exchanger eEXl . Point 24: The method according to any one of points 20 to 23, where said steps B3) and B8) are conducted by heat exchange inside the second oxygen and carbon monoxide heat exchanger eEX2. Point 25: The method according to the preceding point, where said step B6) is conducted in a refrigerant fluid heat exchanger EXfr. Point 26: The method according to any one of points 20 to 25, where in step Bl) an additional flow F consisting of carbon dioxide and hydrocarbons can further be sent.

Point 27: The method according to any one of points 20 to 26, where in step B2) the combustion gas flow el) is expanded in one or two expansion stages, thus obtaining a first expanded combustion gas flow portion e2 and possibly also a fully expanded combustion gas flow el2, which is subjected to the further steps of:

B9) cooling, thus obtaining a second cooled expanded combustion gas flow el3,

BIO) cooling, thus obtaining a second further- cooled expanded combustion gas flow el4,

B12) compressing said second dehydrated combustion gas flow el5 in a combustion gas compressor eC, thus obtaining a second compressed combustion gas flow el6,

Point 28: The method according to the preceding point, where said steps B9) and B13) are conducted in a third heat exchanger EX3 by heat exchange between the fully expanded combustion gas flow el2 and the second compressed combustion gas flow el6 in countercurrent .

Point 29: The method according to point 27 or 28, where said step BIO) is conducted inside a fourth heat exchanger EX4.

Point 30: The method according to point 20, where a portion e9 is separated from the condensed and pumped combustion gas flow e7 obtained from step B7) , which is subjected to the further steps of:

Point 31: The method according to the preceding point, where said step B15) is conducted in the fourth heat exchanger EX4 by heat exchange with the cooled expanded combustion gas flow el3.

Point 32 : The method according to the preceding point, where said step B16) is conducted in the second heat exchanger eEX2.

Point 33: The method according to any one of the preceding points 20 to 32, where the three flows represented by: - pumped and heated combustion gas flow e8 , second further-heated condensed and pumped combustion gas flow el l and

From the above description, the advantages of fered by the present invention will be immediately apparent to those skilled in the art .

In particular, the method described solves most of the known technical problems inherent in oxycombustion processes , such as the need to provide amounts of high-purity oxygen, for example by means of ASU technologies .

Moreover, the oxy-combustion cycle described combines a Brayton cycle and a Rankine cycle using carbon dioxide as a driving fluid, possibly in the presence of small amounts of water (<20% mol/mol ) , more ef ficient by virtue of the possibility to operate at higher temperatures .

For example , figure 1 shows a thermodynamic cycle comprising a Rankine cycle and a Brayton cycle , where the relative contributions are optimi zed to introduce heat at the highest temperature compatible with the technological constraints of the machines and rej ect heat at the lowest temperature compatible with the availability of a thermal well .

The system also operates with great ef ficiency by virtue of the high energy density of liquid carbon monoxide and oxygen .

The method of the present invention globally allows the so-called peak shaving, because it allows stabili zing the electrical network by absorbing available excess electricity and storing it in the form of liquid gases , in particular carbon monoxide and oxygen, to be subj ected to oxy-combustion to produce energy in periods of shortage , while accumulating liquid carbon dioxide .

Note that the carbon monoxide obtained also is a useful chemical intermediate , which can thus be marketed .

Last but not least , the method of the invention actually is a system for using carbon dioxide , produced by industrial or refinery processes or even environmental processes , which is thus subtracted and/or not released into the atmosphere .

Therefore , the method can allow the exploitation of deposits which have a high carbon dioxide content . For the avoidance of doubt, the method removes carbon dioxide and produces no more.

In the embodiment which does not include vapor and condensates, it is particularly suitable for off- shore applications.

Claims

CLAIMS :

1 . A method for producing and accumulating energy, producing carbon monoxide and oxygen, and using carbon dioxide , comprising an accumulation step A) and an energy generation step B ) , wherein said accumulation step A) is a step in which a flow of carbon monoxide ( CO) and a flow of oxygen and possibly a refrigerated fluid are produced .

2 . A method according to the preceding claim, wherein said step A) comprises the sub-steps of :

3. A method according to the preceding claim, wherein said step A2 ) comprises the further sub-steps of :

A2a ) obtaining a carbon monoxide flow to be puri fied c6 , A2b) obtaining a mainly carbon monoxide and vapor flow cl2, a recycled carbon monoxide flow ell, and a recirculation gas flow cr,

A2c) obtaining a dehydrated carbon monoxide flow cl3,

A2d) obtaining an at least partially liquefied carbon monoxide flow cl7.

4. A method according to the preceding claim, wherein said step A2a) comprises the further substeps of:

A2a4) joining said first cooled initial carbon monoxide flow portion c3 and said second cooled initial carbon monoxide flow portion c3' , thus obtaining a joined cooled carbon monoxide flow c4, A2a5) subjecting said joined cooled carbon monoxide flow c4 to compression in a first compressor cCl, thus obtaining a compressed carbon monoxide flow c5, and to cooling in a first exchanger cEl, thus obtaining said carbon monoxide flow to be purified c6, wherein the heat exchanges of steps A2a2) and A2a3) are conducted by heat exchange with a flow circulating and operating in a Rankine cycle.

5. A method according to claim 3, wherein said sub-step A2b) comprises the still further sub-steps of :

6. A method according to the preceding claim, wherein said sub-step A2bl) comprises the following steps : pl) washing with a physical solvent, p2) separation from the physical solvent, thus obtaining a regenerated physical solvent flow s9 and a physical solvent-separated flow c8, p3) compression and cooling, thus obtaining a physical solvent-separated compressed flow c9 and cooled clO, p4) dehydration in a first Dehydration Unit cDUl, thus obtaining the recycled carbon monoxide flow ell, wherein said recycled carbon monoxide flow ell is joined to the appropriately-heated carbon monoxide flow 3 originating the further appropriately-heated carbon monoxide flow 3' to be sent to step Al ) .

7. A method according to claim 5, wherein said step A2b2) comprises the following steps: pl' ) expanding said flow to be regenerated m2 in an expander of the reaction product flow to be regenerated mEK, thus obtaining an expanded flow to be regenerated m3, optionally with the production of power, p2' ) heating said expanded reaction product flow to be regenerated m3 in a heat exchanger of the reaction product flow to be regenerated mEXl, thus obtaining an expanded and heated reaction product flow to be regenerated m4 , which is sent to a regeneration column CL3 , p3 ' ) obtaining, from said regeneration column CL3 , a basic aqueous flow m5 from the bottom and a carbon dioxide and water flow hl from the head, and obtaining from the latter a gaseous flow forming the recirculation gas flow cr, and possibly also obtaining from said regeneration column CL3 a f low intended for a reboiler of the third column (vEXl ) m8 , which is heated, providing a heated flow exiting from the reboiler m9 , which in turn is sent back to the regeneration column CL3 .

8 . A method according to the preceding claim, wherein said recirculation gas flow cr is j oined to the physical solvent-released carbon monoxide flow c8 .

9. A method according to claim 3 , wherein said step A2d) comprises the still further sub-steps of :

A2dl ) subj ecting said dehydrated carbon monoxide flow cl 3 to a first cooling step, thus obtaining a partially cooled dehydrated carbon monoxide flow cl 4 ,

A2d2 ) subj ecting said partially cooled dehydrated carbon monoxide flow cl 4 to a second cooling step, thus obtaining a cooled dehydrated carbon monoxide flow cl 5 , A2d3) subjecting said cooled dehydrated carbon monoxide flow cl5 to a third cooling step, thus obtaining a further cooled dehydrated carbon monoxide flow cl6,

A2d4) expanding said further cooled dehydrated carbon monoxide flow cl6 by expansion in a first expander cEKl, possibly with the production of power, thus obtaining an at least partially liquefied carbon monoxide flow cl7, which can then be stored in a liquid carbon monoxide tank TCO1, wherein said cooling steps are conducted by heat exchange with a refrigerant circulating in a refrigerant circuit.

10. A method according to claim 2, wherein said step A3) comprises the further sub-steps of:

A3b) cooling said first initial oxygen flow portion o2 in a third heat exchanger EX3a, thus obtaining a first cooled initial oxygen flow portion o3,

A3c) cooling said second initial oxygen flow portion o2' in another third heat exchanger EX3b, thus obtaining a second cooled initial oxygen flow portion o3' , A3d) joining said first cooled initial oxygen flow portion o3 and said second cooled initial oxygen flow portion o3' , thus obtaining a joined cooled oxygen flow o4,

A3f) subjecting said compressed and cooled oxygen flow 06 to cooling, thus obtaining an at least partially liquefied oxygen flow olO, which can then be stored in a liquid oxygen tank T021, wherein the heat exchanges of steps A3b) and A3c) are conducted by heat exchange with a flow circulating and operating in a Rankine cycle and wherein the heat exchanges of step A3f) are conducted by heat exchange with a refrigerant fluid circulating in a refrigerant fluid cycle.

11. A method according to claim 9 or 10, wherein said refrigerant fluid is hydrogen, helium, or nitrogen .

12. A method according to any one of the preceding claims, wherein said step A) is conducted by using excess electric current available in the network .

13. A method according to any one of the preceding claims , wherein said generation step B ) comprises the sub-steps of :

B4 ) dehydrating said expanded and cooled combustion gas flow e3 and obtaining a dehydrated combustion gas flow e5 ,

B5 ) separating a first dehydrated combustion gas flow portion e5 ' and obtaining a dehydrated and further cooled combustion gas first flow portion e5 ' ’ , which is sent to a liquid carbon dioxide tank aTCO21 ,

B6 ) cooling the remaining portion of said dehydrated combustion gas flow e5 , thus obtaining a dehydrated and cooled combustion gas flow e6, which is in liquid form,

14. A method according to the preceding claim, wherein in said step B6) a dehydrated and cooled combustion gas flow portion e6' is separated, which is sent to the liquid carbon dioxide tank aTCO21.

15. A method according to claim 13 or 14, wherein step B4) comprises the further sub-steps of:

B4a) separating a first water portion eWl in a combustion gas separator eSl, thus obtaining a partially dehydrated combustion gas flow e4,

B4b) dehydrating the partially dehydrated combustion gas flow e4 in a combustion gas dehydration unit eDU, thus obtaining the dehydrated combustion gas flow e5, wherein said cooling step B5) is conducted by heat exchange inside the first oxygen and carbon monoxide heat exchanger eEXl and wherein said steps B3) and B8) are conducted by heat exchange inside the second oxygen and carbon monoxide heat exchanger eEX2.

16. A method according to the preceding claim, wherein said step B6) is conducted in a refrigerant fluid heat exchanger EXfr.

17. A method according to any one of claims 13 to 16, wherein in step B2) the combustion gas flow el) is expanded in one or two expansion stages, thus obtaining a first expanded combustion gas flow portion e2 and possibly also a fully expanded combustion gas flow el2, which is subjected to the further steps of:

B9) cooling, thus obtaining a second cooled expanded combustion gas flow el3,

B12) compressing said second dehydrated combustion gas flow el5 in a combustion gas compressor eC, thus obtaining a second compressed combustion gas flow el6, B13) heating the second compressed combustion gas flow el6, thus obtaining a second compressed and heated combustion gas flow el7,

B14) further heating the second compressed and heated combustion gas flow el7, thus obtaining a second compressed and further heated combustion gas flow el8, wherein said steps B9) and B13) are conducted in a third heat exchanger eEX3 for heat exchange between the fully expanded combustion gas flow el2 and the second compressed combustion gas flow el6 in countercurrent, and wherein said step BIO) is conducted in a fourth heat exchanger eEX4 for heat exchange with the expanded and cooled combustion gas flow el3.

18. A method according to claim 13, wherein a portion e9 is separated from the condensed and pumped combustion gas flow e7 obtained from step B7) , which is subjected to the further steps of:

B16) further heating, thus obtaining a second further-heated condensed and pumped combustion gas flow ell, wherein said step B15) is conducted in the fourth heat exchanger EX4 for the heat exchange with the cooled expanded combustion gas flow el3, and wherein said step B16 ) is conducted in the second heat exchanger eEX2 .

19. A method according to any one of the preceding claims 13 to 18 , wherein the three flows represented by :

- the pumped and heated combustion gas flow e8 ,

- the second further-heated condensed and pumped combustion gas flow el l and

- the compressed and further-heated combustion gas flow el 8 are j oined in a single flow el 9 which is returned to the combustor for step Bl ) .