Methods and compositions for prevention of fouling in caustic towers

Abstract

Provided are methods and compositions for inhibiting carbonyl based fouling materials of basic wash systems. Said methods comprise contacting the hydrocarbon stream that is or will be subjected to said wash systems with water soluble or water dispersible copolymers. Said copolymers comprise repeat units of ethylenically unsaturated monomers such as acrylic acid with other repeat units such as alkyl acrylates, allyl ethers, ethoxylated allyl repeat units, etc. In other embodiments, a third repeat unit is present and may comprise a hydrophobic moiety such as a styrene repeat unit.

1 . A method for inhibiting the formation of fouling materials comprising contacting a hydrocarbon stream containing carbonyl compounds with an antifoulant and treating said hydrocarbon stream with a basic wash, wherein said antifoulant comprises a polymer having repeat units characterized by the formula 
       
         
           
           
               
               
           
         
       
       wherein a must be present, b or c or b+c is present and d may or may not be present; E is a repeat unit remaining after polymerization of an ethylenically unsaturated compound; each R 1  is independently chosen from H or lower (C 1 -C 4 ) alkyl; R 2  is a hydroxy substituted alkyl or alkylene moiety having from about 1-6 carbon atoms, X is an anionic radical selected from the group consisting of SO 3 , OSO 3 , PO 3 OPO 3  or COO; M is H or hydrogens or any water soluble cationic moiety that counterbalances the valence of the anionic radical X; F is an ethylenically unsaturated hydrophobic moiety; Q in repeat unit c is chosen from C 1 -C 3  alkylene or carbonyl, m is 0 or 1, R 3  is CH 2 —CH—O n  or CH 2 —CH—CH 3 —O n  wherein n is from 1 to about 100 or R 3  is CH 2 —CHOH or CH 2 —CH—(OH)—CH 2 ; R 4  is H, OH, SO 3 M, OSO 3 M, PO 3 M, OPO 3 M, or CO 2 M; with the proviso that when d is present it is present in an amount of 0.01-0.8 moles based on 1 mole of a; either b or c, or both b+c (when both are present) are present in a molar ratio of a:b or a:c or a:(b+c) of 0.1-100. 
     
     
         2 . The method of  claim 1 , wherein about 1-2,000 ppm of said antifoulant is brought into contact with said hydrocarbon stream, based upon 1 million parts of said stream by weight. 
     
     
         3 . The method of  claim 1 , wherein said polymer is a copolymer of acrylic acid (AA) acid/allyl ether or (AA)/allyl hydroxylated alkyl ether. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein said polymer is a terpolymer of AA/AHP SE/styrene. 
     
     
         6 . The method of  claim 1 , wherein said polymer is a copolymer of AA/allylpolyethyleneglycol ether or AA/ethoxylated allyl ether. 
     
     
         7 . The method of  claim 6 , wherein said ethoxylated allyl ether is allylpolyethyoxy (10) sulfate. 
     
     
         8 . The method of  claim 1 , wherein said polymer is a terpolymer of AA/AHPSE/ammonium allylpolyethoxy (10) sulfate or a copolymer of AA/lower alkyl (C 1 -C 4 ) acrylate. 
     
     
         9 . The method of  claim 8 , wherein said lower alkyl (C 1 -C 4 ) acrylate is an hydroxy alkyl acrylate. 
     
     
         10 . The method of  claim 9 , wherein said hydroxy alkyl acrylate is 2 hydroxypropyl acrylate (HPA). 
     
     
         11 . The method of  claim 1 , wherein said polymer is a terpolymer of AA/HPA/AHP SE/styrene. 
     
     
         12 . (canceled) 
     
     
         13 . The method of  claim 1 , wherein the antifoulant is added to the hydrocarbon stream simultaneously with the base wash or is added to the hydrocarbon stream in a hydrocarbon charge line to a basic wash tower or is added to the hydrocarbon stream in an input line to or recycle line from a basic wash tower, or a recycle line from a basic wash tower or to a caustic solution pipeline line. 
     
     
         14 . The method of  claim 1 , wherein said hydrocarbon stream is a methanol to olefin (MTO) process stream or a cracked hydrocarbon stream from the pyrolysis of hydrocarbons. 
     
     
         15 . The method of  claim 14 , wherein the cracked hydrocarbon stream is from the pyrolysis of ethane, propane, butane, naphtha, or mixtures thereof. 
     
     
         16 . The method of  claim 1 , wherein the basic wash has a pH greater than 7.0 and comprises sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrocarbonate, potassium hydrocarbonate, organic amine, or an alkanolamine. 
     
     
         17 . The method according to  claim 1 , wherein the antifoulant further comprises another carbonyl scavenger, said another carbonyl scavenger comprises at least one compound selected from the group consisting of alcohol amines, alkyl amines, keto amines, amino acids, hydrazide compounds, hydroxylamines, reducing sugars, hydroxybenzenes, acetoacetate ester compounds, lactams, oxidizers, and reducers. 
     
     
         18 . (canceled) 
     
     
         19 . A water soluble or water dispersible polymer composition having the structure
   E a G z F d   Formula VI
   wherein a, z, and d are all present; E is a repeat unit remaining after polymerization of an ethylenically unsaturated compound, F is a repeat unit remaining after polymerization of an ethylenically unsaturated hydrophobic moiety; wherein the molar ratio of d:a is about 0.1-0.8 moles of d:1 mole a; z is present in an amount of a:z of 0.1-100 moles a per 1 mole z; G is a repeat unit chosen from VIa, VIb, VIc, or VId or mixtures thereof, wherein VIa is   
       
         
           
           
               
               
           
         
         VIb is 
       
       
         
           
           
               
               
           
         
         wherein R 1  is H or lower (C 1 -C 4 ) alkyl, R 2  is a hydroxy substituted alkyl or alkylene moiety having from about 1-6 carbon atoms, X is an anionic radical selected from the group consisting of SO 3 , OSO 3 , PO 3 , OPO 3 , or COO; M is H or hydrogens or any water soluble cationic moiety that counterbalances the valence of the anionic radical X; Q is chosen from C 1 -C 3  alkylene or carbonyl, m is 0 or 1; R 3  is CH 2 —CH 2 —O n ; —CH 2 CHCH 3 O n  wherein n=1 to 100; or R 3  is hydroxylated lower (C 1 -C 4 ) alkylene; and R 4 , is H, OH, SO 3 M, OSO 3 M, PO 3 M, OPO 3 M, or CO 2 M; 
         VIc is 
       
       
         
           
           
               
               
           
         
         wherein R 1  is as defined above, R 5  is NH or O; R 6  is lower (C 1 -C 4 ) alkyl or alkylene or lower (C 1 -C 4 ) hydroxy substituted alkyl or alkylene; X and M are as defined above; and VId is 
       
       
         
           
           
               
               
           
         
         wherein R 7  is CH 2  or benzyl, and X and M are defined above. 
       
     
     
         20 . The polymer composition as recited in  claim 19 , wherein E is acrylic acid or water soluble salt form thereof (AA). 
     
     
         21 . The polymer composition of  claim 20 , wherein F is styrene. 
     
     
         22 . The polymer composition of  claim 21 , wherein G is VIc and R 5  is NH, or O; R 6  is 2-methyl-1-propane or 2 hydroxypropyl, and X is SO 3 . 
     
     
         23 . (canceled) 
     
     
         24 . The polymer composition of  claim 21 , wherein G is VIa and R 2  is 2 hydroxypropyl and X is SO 3 . 
     
     
         25 . The polymer composition of  claim 21 , wherein G is VIb and Q is CH 2 , m=1; R 3  is CH 2 —CH 2 —O n  and R 4  is SO 3 M. 
     
     
         26 . The polymer composition of  claim 21 , wherein G is VIb and wherein Q=CH 2 , m=O; R 3  is CH 2 CH 2 —O n  and R 4  is OSO 3 M. 
     
     
         27 . The polymer composition of  claim 21 , wherein G comprises both VIa and VIb and wherein R 2  is hydroxypropyl; X is SO 3 ; Q is CH 2 ; m=O; R 3  is CH 2 CH 2 —O n  and R 4  is OSO 3 M. 
     
     
         28 . The polymer composition of  claim 21 , wherein G is VId; wherein R 7  is benzyl or CH 2 , and X is SO 3 . 
     
     
         29 . (canceled) 
     
     
         30 . A water soluble terpolymer composition comprising acrylic acid or acrylic acid salt (AA) repeat units, hydrophobic monomeric repeat units, and a third repeat unit selected from the group consisting of acrylamide repeat units, allyl ether repeat units, lower alkyl (C 1 -C 4 ) acrylate repeat units, ethoxylated or propoxylated allyl repeat units, allyl polyethylene glycol ether repeat units, sulfonated styrene repeat units, and allyl sulfonic acid repeat units. 
     
     
         31 . The water soluble terpolymer composition as recited in  claim 30 , wherein said hydrophobic monomeric repeat units comprise styrene. 
     
     
         32 . The water soluble terpolymer composition as recited in  claim 31 , wherein said third repeat unit is 2-acrylamido-2-methyl-1 propane sulfonic acid (AMPS), allyl hydroxy propyl sulfonate ether (AHPSE), allylpolyethoxy sulfonate (APES), or hydroxypropyl acrylate (HPA). 
     
     
         33 - 36 . (canceled)