Acid gas disposal

Abstract

Acid gas is liquified by compression and cooling, mixed with water under pressure and flowed into a disposal well.

1. The method of disposing of acid gas removed from hydrocarbon products comprising the steps of:
 a) compressing the acid gas to a pressure wherein the acid gas will form a dense fluid,  
 b) forming a dense fluid by cooling the compressed acid gas,  
 c) mixing the acid gas as a dense fluid with sufficient water to form a stable mixture at injection pressure, and  
 d) injecting said stable mixture at injection pressure into a disposal well.  
 
     
     
       2. The method as defined in  claim 1  wherein said compression pressure is at least 650 psi. 
     
     
       3. The method as defined in  claim 1  wherein said water is alkaline and has a pH of at least 7.5 . 
     
     
       4. The method as defined in  claim 1  wherein a minimum pressure of step a) c) is P mix  = 284 + 21 . 55 ×CO 2 % wherein P mix  is said minimum pressure in psi and CO 2 % is the percentage of carbon dioxide in the acid gas. 
     
     
       5. The method as defined in  claim 4  wherein the compressed acid gas is cooled to a temperature of below 130° F. 
     
     
       6. The method as defined in  claim 1  wherein sufficient water is a minimum of
   R H     2     O =0.25+0.10345×CO 2 %  
 
       wherein R H     2     O  is the minimum ratio by volume of water having at least a pH of 7.5 to the dense fluid acid gas. 
     
     
       7. The method as defined in  claim 6  wherein the mixed acid gas and water has a temperature of below 110° F. 
     
     
       8. The method as defined in  claim 1  further comprising:
 e) mixing the acid gas and water in a confluent line, and  
 f) maintaining the pressure in the confluent line to the compression pressure by  
 g) limiting the flow from the confluent line by a pressure control valve.  
 
     
     
       9. The method as defined in  claim 8  wherein
 h) determining that the mixture found is stable by less than a significant amount of any component of the acid gas flashing into the gas phase down stream from the control valve.  
 
     
     
       10. The method as defined in  claim 9  wherein determining that the amount of any component of acid gas flashed is more than a significant amount by formation of hydrates adhering on surfaces of the disposal well. 
     
     
       11. The method as defined in  claim 9  wherein determining that the amount of any component of acid gas flashed is more than a significant amount by formation of gas pockets down stream of the control valve as determined by rapid increase of pressure down stream of the control valve. 
     
     
       12. The method as defined in  claim 9  wherein less than a significant amount of any component of acid gas is flashed is determined when less the 5 percent of said mixture is flashed. 
     
     
       13. The method as defined in  claim 9  wherein less than a significant amount of any component of acid gas is flashed is determined by process simulation. 
     
     
       14. The method as defined in clam  9  wherein less than a significant amount of any component of acid gas is flashed is determined by manual process calculations. 
     
     
       15. The method according to  claim 1  wherein sufficient water is an amount of water such that no more than about  5 %  of the mixed acid gas as a dense fluid and water vaporizes during said injecting step.    
     
     
       16. The method of  claim 1  wherein the compressed acid gas is cooled to a temperature between its freezing point and about  130 ° F.  
     
     
       17. The method of  claim 1  wherein the mixed acid gas and water has a temperature between its freezing point and about  110 ° F.  
     
     
       18. A method of disposing of an acid gas comprising the steps of:
   forming a dense fluid of an acid gas;        mixing the dense fluid acid gas with water to form a stable mixture of acid gas and water having a ratio of water to acid gas of about        R   H2O   = 0 . 25 + 0 . 10345 ×CO   2 %        wherein R   H2O    is the volume of water to one volume of acid gas and CO   2 %  is the percentage of CO   2    on a mole basis in the acid gas; and        injecting the mixture under pressure into a disposal well.      
     
     
       19. The method according to  claim 18  wherein water in an amount less than about twice the ratio R H2O   = 0 . 25 + 0 . 10345 ×CO   2 %  is mixed with acid gas.    
     
     
       20. The method according to  claim 18  wherein water in an amount less than about three times the ratio R H2O   = 0 . 25 + 0 . 10345 ×CO   2 %  is mixed with acid gas.    
     
     
       21. The method according to  claim 18  wherein the pressure in said injecting step is at least about P mix   = 284 + 21 . 55 ×CO   2 %  and wherein P   mix    is the pressure in psi and CO   2 %  is the percentage of carbon dioxide on a mole basis in the acid gas.    
     
     
       22. The method according to  claim 18  wherein the pressure in said injecting step is sufficient to prevent more than about  5 %  of the mixture from flashing.    
     
     
       23. The method according to  claim 18  wherein the dense fluid acid gas is formed by compressing and cooling an acid gas.  
     
     
       24. The method according to  claim 23  wherein the acid gas is compressed to pressure of at least about  650  psi.  
     
     
       25. The method according to  claim 24  wherein the compressed acid gas is cooled to a temperature between its freezing point and about  130 ° F.  
     
     
       26. A method of disposing of an acid gas comprising the steps of:
   mixing an acid gas with water to form a stable mixture that is substantially not a solution of absorbed acid gas in water;        injecting the mixture under pressure into a disposal well.      
     
     
       27. The method according to  claim 26  wherein the acid gas is a dense fluid.  
     
     
       28. The method according to  claim 27  wherein the pressure in said injecting step is at least about P mix   = 284 + 21 . 55 ×CO   2 %  and wherein P   mix    is the pressure in psi and CO   2 %  is the percentage of carbon dioxide on a mole basis in the acid gas.    
     
     
       29. The method according to  claim 27  wherein the pressure in said injecting step is sufficient to prevent more than about  5 %  of the mixture from flashing.    
     
     
       30. The method according to  claim 27  wherein water in an amount less than about three times a ratio of R H2O   = 0 . 25 + 0 . 10345 ×CO   2 % , wherein R   H2O    is the volume of water to one volume of dense fluid acid gas and CO   2 %  is the percentage of CO   2    on a mole basis in the acid gas, is mixed with acid gas.    
     
     
       31. A method of disposing of an acid gas comprising the steps of:
   forming a dense fluid of an acid gas;        mixing the dense fluid acid gas with an amount of water to form a stable mixture of acid gas and water; and        injecting the mixture under pressure into a disposal well.      
     
     
       32. The method according to  claim 31  wherein the pressure in said injecting step is sufficient to prevent more than about  5 %  of the mixture from flashing.    
     
     
       33. The method according to  claim 31  wherein water in a volume amount of less than about eleven times the volume of acid gas is mixed.  
     
     
       34. The method according to  claim 31  wherein water in a volume amount of less than about thirty- three times the volume of acid gas is mixed.    
     
     
       35. The method according to  claim 31  wherein water in an amount sufficient to prevent the formation of hydrates in the disposal well is mixed with acid gas.  
     
     
       36. The method according to  claim 35  wherein the formation of hydrates is determined by an increase in injection pressure of about  5 - 10  psi per hour.  
     
     
       37. A method of disposing of a dense fluid acid gas comprising the steps of:
   mixing the dense fluid acid gas with water to form a stable mixture; and        injecting the mixture under pressure into a disposal well such that less than about  5   %  of the mixture vaporizes during injection.      
     
     
       38. The method of disposing of acid gas removed from hydrocarbon products comprising the steps of:
   a. compressing the acid gas to a pressure wherein the acid gas will form a dense fluid,        b. forming a dense fluid by cooling the compressed acid gas,        c. mixing the acid gas as a dense fluid with sufficient liquid water to form a stable mixture at injection pressure, and        d. injecting said stable mixture at injection pressure into a disposal well.