Method of removing co2 from a contaminated hydrocarbon stream

Abstract

The present invention provides a method to separate CO2 from a contaminated hydrocarbon-containing stream. The method comprises obtaining a multiphase contaminated hydrocarbon-containing stream ( 100 ) containing at least a vapour phase, a liquid phase and a solid phase, creating a slurry stream ( 120 ) from the multiphase stream. The slurry stream is fed to a crystallization chamber comprising CO2 seed particles. A liquid hydrocarbon stream ( 170 ) is obtained from the crystallization chamber ( 91 ) and a concentrated slurry ( 140 ) is obtained. The concentrated slurry ( 140 ) is removed from the crystallization chamber ( 91 ) by means of an extruder ( 142 ), thereby obtaining solid CO2. A feedback stream ( 141 ) is obtained from the solid CO2 comprising CO2 seed particles having an average size greater than 100 micron. The feedback stream ( 141 ) is passed into the crystallization chamber ( 91 ).

1 . A method to separate CO2 from a contaminated hydrocarbon-containing stream; the method comprising
 (a) providing a multiphase contaminated hydrocarbon-containing stream, from the contaminated hydrocarbon-containing stream, the multiphase contaminated hydrocarbon-containing stream containing at least a liquid phase and a solid phase, wherein the solid phase comprises CO2 particles;   (b1) feeding a slurry stream obtained from the multiphase contaminated hydrocarbon-containing stream to a crystallization chamber, the crystallization chamber comprising seed particles, the seed particles comprising CO2;   (b2) obtaining a liquid hydrocarbon stream from the crystallization chamber, thereby forming a concentrated slurry in the crystallization chamber;   (b3) removing the concentrated slurry from the crystallization chamber by means of an extruder and obtaining a CO2 enriched solid product and a methane enriched liquid hydrocarbon stream from the extruder.   
     
     
         2 . The method according to  claim 1 , wherein the method further comprises
 (b4) obtaining a CO2 feedback stream from the CO2 enriched solid product obtained in (b3), the feedback stream comprises CO2,   (b5) feeding back the CO2 feedback stream to a feedback inlet, the feedback inlet being in the crystallization chamber or at a position upstream of the crystallization chamber to provide seed particles.   
     
     
         3 . The method according to  claim 2 , wherein the seed particles provided in (b5) have an average size greater than  20  micron. 
     
     
         4 . The method according to  claim 2 , wherein (b4) comprises obtaining a CO2 feedback stream comprising CO2 seed particles and (b5) comprises passing the feedback stream ( 141 ) into the crystallization chamber ( 91 ) to provide the seed particles to the crystallization chamber. 
     
     
         5 . The method according to  claim 2 , wherein (b4) comprises breaking the solid CO2 obtained in (b3) to form the seed particles. 
     
     
         6 . The method according to  claim 2 , wherein (b4) comprises adding a carrier fluid, such as a liquid natural gas stream, to the feedback stream. 
     
     
         7 . The method according to  claim 2 , wherein (b4) comprises heating at least part of the CO2 enriched solid product thereby creating a liquid CO2 enriched stream, and forming the feedback stream from at least part of the liquid CO2 enriched stream, the CO2 seed particles being formed from the liquid CO2 enriched stream. 
     
     
         8 . The method according to  claim 7 , wherein (b5) comprises spraying the liquid CO2 enriched stream into a feedback position thereby creating seed particles. 
     
     
         9 . The method according to  claim 7 , wherein (b5) comprises processing the liquid CO2 enriched stream to form the CO2 seed particles and feeding back the CO2 seed particles by passing the CO2 seed particles to the crystallization chamber or to a position upstream of the crystallization chamber to provide seed particles. 
     
     
         10 . The method according to  claim 1 , wherein the method comprises combining the methane enriched liquid hydrocarbon stream and the liquid hydrocarbon stream obtained in step (b2). 
     
     
         11 . The method according to  claim 1 , wherein (b2) further comprises subjecting the liquid hydrocarbon stream obtained from the crystallization chamber, to a polishing treatment to obtain a polished liquid hydrocarbon stream and a residue stream, wherein the method further comprises passing the polished liquid hydrocarbon stream to the LNG storage tank. 
     
     
         12 . The method according to  claim 1 , wherein the extruder comprises a housing, the housing comprising at least one opening for discharging the methane enriched liquid hydrocarbon stream. 
     
     
         13 . The method according to  claim 1 , wherein step (a) comprises
 (a1) providing a contaminated hydrocarbon-containing gas stream;   (a2) cooling the contaminated hydrocarbon-containing gas stream in a first heat exchanger thereby obtaining a cooled contaminated hydrocarbon-containing stream;   (a3) cooling the cooled contaminated hydrocarbon-containing stream in an expander thereby obtaining a partially liquefied stream;   (a4) separating the partially liquefied stream in a separator thereby obtaining a gaseous stream and a liquid stream;   (a5) expanding the liquid steam obtained in step (a4) thereby obtaining the multiphase contaminated hydrocarbon-containing stream, the multiphase contaminated hydrocarbon-containing stream containing at least a vapour phase, a liquid phase and a solid phase, wherein the solid phase comprises CO2 particles.   
     
     
         14 . The method according to  claim 1 , wherein the method further comprises
 (d) passing the gaseous stream obtained in step (a4) through the first heat exchanger thereby obtaining a heated gaseous stream); and   (e) compressing the heated gaseous stream thereby obtaining a compressed gas stream; and (f) combining the compressed gas stream obtained in step (e) with the contaminated hydrocarbon-containing gas stream provided in step (a1).   
     
     
         15 . The method according to  claim 1 , wherein the extruder exerts an extrusion force which pushes the solid phase particles present in the concentrated slurry together to form larger CO2 particles, CO2 chunks or a (semi) continuous solid CO2 product stream, and the extrusion force squeezes out the liquid present in the concentrated slurry, e.g. via holes or filters in the housing of the extruder. 
     
     
         16 . A system for separating CO2 from a contaminated hydrocarbon-containing stream; the system comprising
 a conduit suitable for carrying a multiphase contaminated hydrocarbon-containing stream, the multiphase contaminated hydrocarbon-containing stream containing at least a liquid phase and a solid phase, wherein the solid phase comprises CO2 particles,   a solid-liquid separator comprising a crystallization chamber, the crystallization chamber comprising
 a slurry inlet being in fluid communication with the conduit to receive a slurry stream obtained from the multiphase contaminated hydrocarbon-containing stream, 
 a fluid outlet for discharging a liquid hydrocarbon stream from the crystallization chamber, 
 a concentrated slurry outlet, 
   an extruder being in fluid communication with the crystallization chamber via the concentrated slurry outlet to receive concentrated slurry from the crystallization chamber and discharge a CO2 enriched solid product and a methane enriched liquid hydrocarbon stream.   
     
     
         17 . System The system according to  claim 16 , wherein the crystallization chamber comprises an overhead venting outlet. 
     
     
         18 . System The system according to  claim 16 , wherein the slurry inlet is formed by a downcomer with a discharge opening, the solid-liquid separator comprises a weir having an upper edge positioned at a level gravitational above or below the discharge opening, wherein the fluid outlet for discharging the liquid hydrocarbon stream from the crystallization chamber is positioned at an opposite side of the weir than the discharge opening of the downcomer. 
     
     
         19 . The system according to  claim 16 , wherein the system comprises a seed particle forming device, such as a scraper, arranged to obtain seed particles from the solid CO2 obtained from the extruder, the seed particles having an average size greater than 100 micron. 
     
     
         20 . System The system according to  claim 16 , wherein the extruder comprises holes or filters in a housing of the extruder through which the methane enriched liquid hydrocarbon stream is obtained.