Method of removing carbon dioxide from a fluid stream and fluid separation assembly

Abstract

The invention relates to a method of removing carbon dioxide from a fluid stream by a fluid separation assembly. The fluid separation assembly has a cyclonic fluid separator with a tubular throat portion arranged between a converging fluid inlet section and a diverging fluid outlet section and a swirl creating device. The separation vessel has a tubular section positioned on and in connection with a collecting tank. In the method, a fluid stream with carbon dioxide is provided. Subsequently, a swirling motion is imparted to the fluid stream so as to induce outward movement. The swirling fluid stream is then expanded such that components of carbon dioxide in a meta-stable state within the fluid stream are formed. Subsequently, the outward fluid stream with the components of carbon dioxide is extracted from the cyclonic fluid separator and provided as a mixture to the separation vessel. The mixture is then guided through the tubular section towards the collecting tank while providing processing conditions such that solid carbon dioxide is formed. Finally, solidified carbon dioxide is extracted.

1 . Method of removing carbon dioxide from a fluid stream by a fluid separation assembly comprising:
 a cyclonic fluid separator comprising a throat portion arranged between a converging fluid inlet section and a diverging fluid outlet section and a swirl creating device configured to create a swirling motion of the carbon dioxide containing fluid within at least part of the cyclonic fluid separator, the converging fluid inlet section comprising a first inlet for fluid components and the diverging fluid outlet section comprising a first outlet for carbon dioxide depleted fluid and a second outlet for carbon dioxide enriched fluid;   a separation vessel having a first section in connection with a collecting tank, said first section being provided with a second inlet connected to said second outlet of said cyclonic fluid separator, and said collecting tank being provided with a third outlet for solidified carbon dioxide, wherein said separation vessel is operated at a pressure and temperature combination that is at or in the vicinity of the phase boundary between a vapour/liquid/solid coexistence region (IVb) and the vapour/solid coexistence region (IVa);   
       the method comprising:
 providing a fluid stream at said first inlet, said fluid stream comprising carbon dioxide; 
 imparting a swirling motion to the fluid stream so as to induce outward movement of at least one of condensed components and solidified components within the fluid stream downstream the swirl creating device and to form an outward fluid stream; 
 expanding the swirling fluid stream, so as to form components of liquefied carbon dioxide in a meta-stable state within said fluid stream, and induce outward movement of said components of liquefied carbon dioxide in said meta-stable state under the influence of said swirling motion; 
 extracting the outward fluid stream comprising said components of liquefied carbon dioxide in said meta-stable state from said cyclonic fluid separator through said second outlet; 
 providing said extracted outward fluid stream as a mixture to said separation vessel through said second inlet; 
 guiding said mixture through said first section of said separation vessel towards said collecting tank, while providing processing conditions in said first section such that solidified carbon dioxide is formed out of said components of liquefied carbon dioxide in said meta-stable state; 
 extracting the solidified carbon dioxide through said third outlet ( 28 ). 
 
     
     
         2 . Method according to  claim 1 , wherein the method further comprises:
 forming a layer of solidified carbon dioxide extracted from the third outlet ( 28 ) on a feed side ( 42 ) of a perforated screen ( 40 ) comprising openings ( 41 ) towards a collection side ( 43 ),   applying temperature and pressure conditions on the collection side ( 43 ) of the perforated screen ( 40 ) to melt of carbon dioxide from the layer and collect the melted carbon dioxide through the openings ( 41 ) at the collection side ( 43 ).   
     
     
         3 . Method according to any one of the  claims 1 - 2 , wherein the collection side ( 43 ) is operated at a temperature and pressure combination for which carbon dioxide is liquid. 
     
     
         4 . Method according to any one of the  claims 2 - 3 , wherein the feed side ( 42 ) is operated at a first pressure and the collection side ( 43 ) is operated at a second pressure, the second pressure being equal or lower than the first pressure. 
     
     
         5 . Method according to any one of the  claims 2 - 4  wherein the temperature at the collection side ( 43 ) is in the range of minus 55° C.-0° C., and higher than a temperature at the feed side ( 42 ) 
     
     
         6 . Method according to any one of the  claims 2 - 5 , wherein the openings ( 41 ) have an inlet size (D 42 ) at the feed side ( 42 ) that is greater than an outlet size (D 43 ) at the collection side ( 43 ). 
     
     
         7 . Method according to  claim 6 , wherein the outlet size (D 43 ) is approximately equal to or substantially smaller than the grain size of solidified carbon dioxide. 
     
     
         8 . Method according to any one of the preceding claims, wherein said extracted outward fluid stream is provided to said separation vessel tangential to a perimeter of the first section, such that a rotational flow in the first section ( 22 ) is generated. 
     
     
         9 . Method according to any one of the preceding claims, wherein said first section of the separation vessel is further provided with a fifth outlet, and said method further comprises extracting carbon dioxide depleted gaseous components through said fifth outlet. 
     
     
         10 . Method according to any one of the  claims 8 - 9 , wherein the fifth outlet is formed by a vortex finder, comprising a substantially vertical pipe extending into the first section in a through an upper part of the first section in a downward direction, wherein the lower end of the pipe is at a vertical lower position than the second inlet. 
     
     
         11 . Method according to any one of the preceding claims, wherein there is provided a vortex breaker ( 30 ) in between the first section and the collection tank. 
     
     
         12 . Method according to any one of the preceding claims, wherein said collecting tank is further provided with a fourth outlet ( 26 ), and said method further comprises extracting hydrocarbon liquid components through said fourth outlet ( 26 ). 
     
     
         13 . Method according to  claim 12 , wherein the hydrocarbon liquid components through the fourth outlet ( 26 ) are fed back to the cyclonic fluid separator. 
     
     
         14 . Method according to any one of the preceding claims, wherein said separation vessel further comprises a cooling arrangement configured to provide a predetermined temperature condition therein, said temperature condition enabling solidification of the carbon dioxide enriched fluid. 
     
     
         15 . Method according to any one of the preceding claims, wherein said fluid separation assembly further comprises a scroll type discharger in connection with said third outlet ( 28 ), and said extracting the solidified carbon dioxide is performed by conveying by means of said scroll type discharger. 
     
     
         16 . Method according to any one of the preceding claims, wherein said fluid stream comprises a mole percentage carbon dioxide larger than 10%. 
     
     
         17 . Method according to any one of the preceding claims, wherein said expanding of the swirling fluid stream is such that the swirling fluid stream reaches supersonic velocity. 
     
     
         18 . Method according to  claim 17 , wherein said expanding is further such that a temperature below 200 K is reached. 
     
     
         19 . Method according to  claim 17  or  18 , wherein said expanding is further such that a pressure is reached below 50% of a pressure at the first inlet of the cyclonic fluid separator. 
     
     
         20 . Method according to any one of the preceding claims, wherein said providing said outward fluid stream as a mixture to said separation vessel through said second inlet is arranged such that a tangential fluid stream is provided. 
     
     
         21 . Fluid separation assembly for removing carbon dioxide from a fluid stream, the fluid separation assembly comprising:
 a cyclonic fluid separator comprising a throat portion arranged between a converging fluid inlet section and a diverging fluid outlet section and a swirl creating device configured to create a swirling motion of the carbon dioxide containing fluid within at least part of the separator, the converging fluid inlet section comprising a first inlet for fluid components and the diverging fluid outlet section comprising a first outlet for carbon dioxide depleted fluid and a second outlet for carbon dioxide enriched fluid;   a separation vessel having a first section in connection with a collecting tank, said section being provided with a second inlet connected to said second outlet of said cyclonic fluid separator, and said collecting tank being provided with a third outlet ( 28 ) for solidified carbon dioxide, wherein said separation vessel is operated at a pressure and temperature combination that is at or in the vicinity of the phase boundary between a vapour/liquid/solid coexistence region (IVb) and the vapour/solid coexistence region (IVa);   
       wherein said fluid separation assembly is arranged to:
 receive a fluid stream comprising carbon dioxide at said first inlet; 
 impart a swirling motion to the fluid stream so as to induce outward movement of at least one of condensed components and solidified components within the fluid stream downstream the swirl creating device and to form an outward fluid stream; 
 expand the swirling fluid stream, so as to form components of liquefied carbon dioxide in a meta-stable state within said fluid stream, and induce outward movement of said components of liquefied carbon dioxide in said meta-stable state under the influence of said swirling motion; 
 extract the outward fluid stream comprising said components of liquefied carbon dioxide in said meta-stable state from said cyclonic fluid separator through said second outlet; 
 provide said extracted outward fluid stream as a mixture to said separation vessel through said second inlet; 
 guide said mixture through said first section of said separation vessel towards said collecting tank, while providing processing conditions in said first section such that solidified carbon dioxide is formed out of said components of liquefied carbon dioxide in said meta-stable state; 
 enable extraction of the solidified carbon dioxide through said third outlet ( 28 ). 
 
     
     
         22 . Fluid separator assembly according to  claim 21 , wherein the fluid separator assembly further comprising:
 a perforated screen ( 40 ) comprising a feed side ( 42 ) and a collection side ( 43 ), the feed side ( 42 ) positioned to collect solidified carbon dioxide from the third outlet ( 28 ), the perforated screen further comprising openings ( 41 ) towards the collection side ( 42 ),   
       wherein said fluid separation assembly is further arranged to:
 form a layer of solidified carbon dioxide extracted from the third outlet ( 28 ) on the feed side ( 42 ) of the perforated screen ( 40 ), 
 applying temperature and pressure conditions on the collection side ( 43 ) of the perforated screen ( 40 ) to melt of carbon dioxide from the layer and collect the melted carbon dioxide through the openings ( 41 ) at the collection side ( 43 ). 
 
     
     
         23 . Fluid separator assembly according to  claim 22 , wherein the collection side ( 43 ) is arranged to be operated at a temperature and pressure combination for which carbon dioxide is liquid. 
     
     
         24 . Fluid separator assembly according to  claims 22 - 23  wherein the feed side ( 42 ) is arranged to be operated at a first pressure and the collection side ( 43 ) is operated at a second pressure, the second pressure being equal or lower than the first pressure. 
     
     
         25 . Fluid separator assembly according to any one of the  claims 22 - 24 , wherein the fluid separator assembly is arranged to be at a temperature at the collection side ( 43 ) that is in the range of minus 55° C.-0° C., but higher than a temperature at the feed side ( 42 ). 
     
     
         26 . Fluid separator assembly according to any one of the  claims 22 - 25 , wherein the openings ( 41 ) have an inlet size (D 42 ) at the feed side ( 42 ) that is greater than an outlet size (D 43 ) at the collection side ( 43 ). 
     
     
         27 . Fluid separator assembly according to  claim 26 , wherein the outlet size (D 43 ) is approximately equal to or substantially smaller than the grain size of solidified carbon dioxide. 
     
     
         28 . Fluid separator assembly according to anyone of the  claims 21 - 27 , wherein said second inlet is a tangential inlet to a perimeter of the first section, such that a rotational flow in the first section ( 22 ) is generated. 
     
     
         29 . Fluid separation assembly according to any one of the  claims 21 - 28 , wherein said first section is further provided with a fifth outlet, said fifth outlet being configured to enable extraction of carbon dioxide depleted gaseous components. 
     
     
         30 . Fluid separation assembly according to any one of the  claims 28 - 29 , wherein the fifth outlet is formed by a vortex finder, comprising a substantially vertical pipe extending into the first section through an upper part of the first section in a downward direction, wherein the lower end of the pipe is at a vertical lower position than the second inlet. 
     
     
         31 . Fluid separation assembly according to any one of the  claims 21 - 30 , wherein there is provided a vortex breaker ( 30 ) in between the first section and the collection tank. 
     
     
         32 . Fluid separation assembly according to any one of the  claims 21 - 31 , wherein said collecting tank is further provided with a fourth outlet ( 26 ), said fourth outlet ( 26 ) being configured to enable extraction of hydrocarbon liquid components. 
     
     
         33 . Fluid separation assembly according to  claim 32 , wherein the fluid separation assembly comprises a feedback conduit ( 81 ), the feedback conduit ( 81 ) being arranged to feedback the hydrocarbon liquid components from the fourth outlet ( 26 ) to the cyclonic fluid separator. 
     
     
         34 . Fluid separation assembly according to any one of  claims 21 - 33 , wherein said separation vessel further comprises a cooling arrangement configured to provide a predetermined temperature condition therein, said temperature condition enabling solidification of a carbon dioxide enriched fluid. 
     
     
         35 . Fluid separation assembly according to any one of  claims 21 - 34 , wherein said fluid separation assembly further comprises a scroll type discharger in connection with said third outlet ( 28 ), said scroll type discharger being configured to enable extraction of said solidified carbon dioxide through said third outlet ( 28 ) by conveying. 
     
     
         36 . Fluid separation assembly according to any one of  claims 21 - 35 , wherein said second inlet of said separation vessel is arranged tangent to the circumference of the separation vessel.