Organic acid removal from liquid hydrocarbon product streams

Abstract

Systems and processes for removing organic acids from liquid hydrocarbon product streams are provided. The systems and processes can include injecting an ammoniated water wash into a liquid hydrocarbon product stream, such as an effluent stream from a methanol conversion process, and subsequently separating the treated liquid hydrocarbon product stream from the wash water. The addition of ammonia can reduce the amount of water wash by an unexpected amount.

1 . A method for removing organic acids from a liquid hydrocarbon product stream, comprising:
 exposing a liquid hydrocarbon product stream comprising naphtha boiling range compounds, light ends, and 1 ppmw or more of organic acids to a water wash stream comprising ammonia to form a treated liquid hydrocarbon product stream, an amount of the water wash stream being 0.5 L to 20 L per barrel of the liquid hydrocarbon product stream, the water wash comprising 4.0 g or more of ammonia per barrel of the liquid hydrocarbon product stream.   
     
     
         2 . The method of  claim 1 , wherein the liquid hydrocarbon product stream has a T95 distillation point of 225° C. or less. 
     
     
         3 . The method of  claim 1 , wherein the naphtha boiling range compounds comprise a Research Octane Number (RON) of 80 or more. 
     
     
         4 . The method of  claim 1 , wherein the liquid hydrocarbon product stream, prior to the exposing, further comprises 10 ppmw to 3000 ppmw of water. 
     
     
         5 . The method of  claim 1 , wherein the liquid hydrocarbon product stream comprises 1 ppmw to 500 ppmw of the organic acids. 
     
     
         6 . The method of  claim 1 , further comprising, subsequent to the exposing, separating the water wash stream from the treated liquid hydrocarbon product stream to form a separated water wash stream. 
     
     
         7 . The method of  claim 6 , wherein the separated water wash stream comprises a pH of 5.5 or more. 
     
     
         8 . The method of  claim 1 , wherein the water wash comprises 7.5 g or more of ammonia per barrel of hydrocarbon liquid product. 
     
     
         9 . The method of  claim 1 , i) wherein the organic acids comprise organic acids having 5 carbon atoms or less; ii) wherein the organic acids comprise formic acid, acetic acid, propionic acid, butyric acid, or a combination thereof; or iii) a combination of i) and ii). 
     
     
         10 . The method of  claim 1 , wherein a ratio of moles of the ammonia in the water wash to moles of the organic acids in the liquid hydrocarbon product stream is 1.5 or more. 
     
     
         11 . The method of  claim 1 , further comprising separating at least a portion of the C 2−  hydrocarbons from the treated liquid hydrocarbon product stream. 
     
     
         12 . The method of  claim 11 , wherein the separating at least a portion of the C 2−  hydrocarbons from the treated liquid hydrocarbon product stream comprises exposing the treated liquid hydrocarbon product stream to a de-ethanizer. 
     
     
         13 . The method of  claim 1 , further comprising, prior to the exposing the liquid hydrocarbon product stream to the water wash stream comprising ammonia, converting one more oxygenates to an intermediate product stream; and separating at least a portion of water and gas from the intermediate product stream to form the liquid hydrocarbon product stream. 
     
     
         14 . The method of  claim 1 , wherein the liquid hydrocarbon product stream is derived from an oxygenate conversion process. 
     
     
         15 . A method for removing organic acids from a liquid hydrocarbon product stream, comprising:
 exposing a liquid hydrocarbon product stream comprising naphtha boiling range compounds, light ends, and 1 ppmw or more of organic acids to a water wash stream comprising ammonia to form a treated liquid hydrocarbon product stream, wherein the water wash stream is present in an amount of 0.5 L to 20 L per barrel of the liquid hydrocarbon product stream, and wherein a ratio of moles of ammonia in the water wash to moles of the organic acids in the liquid hydrocarbon product stream is 1.5 or more.   
     
     
         16 . The method of  claim 15 , further comprising, subsequent to the exposing, separating the water wash stream from the treated liquid hydrocarbon product stream to form a separated water wash stream. 
     
     
         17 . The method of  claim 16 , wherein the separated water wash stream comprises a pH of 5.5 or more. 
     
     
         18 . The method of  claim 15 , wherein the liquid hydrocarbon product stream comprises 1 ppmw to 500 ppmw of the organic acids. 
     
     
         19 . The method of  claim 15 , i) wherein the organic acids comprise organic acids having 5 carbon atoms or less; ii) wherein the organic acids comprise formic acid, acetic acid, propionic acid, butyric acid, or a combination thereof; or iii) a combination of i) and ii). 
     
     
         20 . The method of  claim 15 , further comprising separating at least a portion of the C 2−  hydrocarbons from the treated liquid hydrocarbon product stream.