Methods and compositions for preventing fouling of alkali treatment columns

Abstract

The invention relates to methods and compositions for preventing fouling of alkali treatment columns. The present disclosure provides methods and compositions for inhibiting carbonyl-based fouling materials for alkaline wash systems. The method comprises contacting a hydrocarbon stream that is subjected to or is to be subjected to the scrubbing system with a water-soluble or water-dispersible copolymer. The copolymer comprises repeating units of ethylenically unsaturated monomers such as acrylic acid and other repeating units such as alkyl acrylates, allyl ethers, ethoxylated allyl repeating units, and the like. In other embodiments, the third repeat unit is present and may comprise a hydrophobic moiety, such as a styrene repeat unit.

Description

[0001] The present application is a divisional application of the invention application with patent application number 201680085821.7, application date March 18, 2016, and invention name “Method and composition for preventing fouling of alkali treatment tower”. Field of the Invention

[0002] The present invention relates to methods and compositions for inhibiting the formation of scale deposits in alkaline scrubbing systems of the type suitable for cleaning impurities such as those that may be formed from liquid or vapor phase hydrocarbon-containing streams by aldol condensation reactions. Background of the Invention

[0004] Olefin compounds such as ethylene, propylene, butenes and pentenes can be formed by methanol to olefins (MTO) or various pyrolysis cracking processes. In these processes, various carbonyl compounds such as aldehydes and ketones are usually formed. Generally, due to the specific raw materials and reactor operating parameters used for the reaction, about 1-200 ppm by weight of carbonyl compounds are found in the gas stream relative to the hydrocarbon stream with a concentration greater than 1,000 parts per million (ppm) sometimes encountered.

[0005] The hydrocarbon product stream formed by the cracking or MTO process is cooled and sometimes compressed. The product gas stream can be passed through an alkaline scrubbing system (pH>7) to remove acidic components such as hydrogen sulfide and carbon dioxide. In many cases, the carbonyl compounds present, such as aldehydes, will undergo polymerization to form condensation polymers known as aldol polymers or red oils. These aldol polymers or red oils have low solubility in alkaline washes and hydrocarbon media and can deposit on the cleaning trays, pipes and other internal surfaces of process equipment, causing fouling and eventual blockage. These deposits can restrict flow through the equipment and can cause unwanted pressure drops, resulting in reduced process throughput, increased operating costs, and shutdowns of equipment for periodic cleaning.

[0006] Alkaline scrubbing systems where treatment is required to inhibit such polymer-based foulants include amine acid gas scrubbers, such as MEA, DEA, isopropylamine, butylamine, etc., and caustic scrubbing systems.

[0007] Generally, alkaline scrubbing requires contacting gaseous olefins with an alkaline aqueous solution in a scrubbing tower to remove hydrogen sulfide, carbon dioxide and other oxygenated compounds generated therefrom. Alkaline scrubbing is particularly suitable for alkaline scrubbing processes after pyrolysis cracking of hydrocarbons such as ethane, propane, butane, naphtha and mixtures thereof to produce corresponding gaseous ethylene, propylene, butadiene, etc., or after the MTO production process containing carbonyls and other contaminants. SUMMARY OF THE INVENTION

[0009] In one embodiment of the present invention, a method for inhibiting the formation of fouling materials is provided, which comprises contacting a hydrocarbon medium containing an aldehyde compound with an antifouling agent. The hydrocarbon medium is treated in an alkaline scrubbing system. The antifouling agent may comprise a polymer having repeating units characterized by the formula

[0010] Formula I

[0011]

[0012] wherein a must be present, b or c or b+c are present and d may or may not be present; E is a repeating unit remaining after polymerization of the ethylenically unsaturated compound and may be, for example, (meth)acrylic acid or (meth)acrylamide; each R 1 are independently selected from H or lower (C 1 -C 4 ) alkyl; R 2 is a hydroxy-substituted alkyl or alkylene moiety having about 1 to 6 carbon atoms, and X is selected from SO 3 、OSO 3 ,PO 3 、OPO 3 or anionic groups of COO; M is one or more hydrogen or any water-soluble cationic moiety that balances the valence of the anionic group X and can be Ca, Na, K, NH 4 etc.; F is an olefinically unsaturated hydrophobic part such as styrene and its derivatives, acrylonitrile, having (C 1 -C 18 ) alkyl olefin, alkyl (meth) acrylate; Q in the repeating unit c is selected from C 1 -C 3 alkylene or carbonyl, m is 0 or 1, R 3 yes or Where n is 1 to about 100 or R 3 Yes CH 2 -CHOH or CH 2 -CH-(OH)-CH 2 ; R 4 It is H, OH, SO 3 M. OSO 3 M.PO 3 M. OPO 3 M or CO 2 M; provided that when d is present, it is present in an amount of 0.01-0.8 moles based on 1 mole of a; one of b or c, or b+c (when both are present) is present in a molar ratio of a:b or a:c or a:(b+c) of 0.1-100, or in certain exemplary embodiments, in a molar ratio of 1-10.

[0013] In certain embodiments, the polymeric antifoulant may comprise a copolymer of acrylic acid (AA) and an allyl ether. In other embodiments of the present invention, the polymeric antifoulant may be acrylic acid (AA) allyl hydroxylated alkyl ether, also known as 1-propanesulfonic acid, 2-hydroxy-3 (2-propyleneoxy) monosodium salt (AHPSE).

[0014] The polymer antifouling agent may also be a terpolymer of AA / AHPSE / styrene or it may be a copolymer of acrylic acid and allyl polyethylene glycol ether in certain embodiments. In some cases, the polymer may comprise a copolymer of acrylic acid and ethoxylated allyl ether. In other embodiments, the copolymer may comprise acrylic acid and a lower alkyl acrylate such as a hydroxy-substituted alkyl acrylate.

[0015] In another aspect of the present invention, there is provided a novel water-soluble or water-dispersible polymer composition having the following structure:

[0016] Formula VI

[0017]

[0018] where a, z and d all exist; It is the repeating unit remaining after the polymerization of ethylenically unsaturated compounds. is the remaining repeating unit after polymerization of the ethylenically unsaturated hydrophobic moiety; wherein the molar ratio of d:a is about 0.1-0.8 mole d:1 mole a; z is present in an amount of a:z of 0.1-100, 1-10 mole a / 1 mole z, and in some embodiments, 1-10 mole a / mole z; is a repeating unit selected from VIa, VIb, VIc or VId or a mixture thereof, wherein VIa is

[0019]

[0020] VIb is

[0021]

[0022] Where R 1 Is H or low (C 1 -C 4 ) alkyl, R 2 is a hydroxy-substituted alkyl or alkylene moiety having about 1 to 6 carbon atoms, and X is selected from SO 3 、OSO 3 ,PO 3 、OPO 3 or an anionic group of COO; M is H or hydrogen or any water-soluble cationic moiety that balances the valence of the anionic group X; Q is selected from C 1 -C 3Alkylene or carbonyl, m is 0 or 1; R 3 yes Where n = 1-100; or R 3 It is a hydroxylated low (C 1 -C 4 ) alkylene; and R 4 It is H, OH, SO 3 M. OSO 3 M.PO 3 M. OPO 3 M or CO 2 M;

[0023] VIc is

[0024]

[0025] Where R 1 As defined above, R 5 is NH or O; R 6 Is low level (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

[0026]

[0027] Where R 7 Yes CH 2 or benzyl, and X and M are as defined above.

[0028] In a further aspect of the present invention, a novel water-soluble terpolymer composition is provided, which comprises acrylic acid or acrylate repeating units, hydrophobic repeating units such as styrene and its derivatives, acrylonitrile, having (C 1 -C 18 ) alkyl olefins, alkyl (meth) acrylates, and repeating units selected from acrylamide, allyl ether repeating units, lower alkyl (C 1 -C 4 ) acrylate repeating units, ethoxylated or propoxylated allyl repeating units, allyl polyethylene glycol ether repeating units, sulfonated styrene repeating units and allyl sulfonic acid repeating units. A terpolymer in which the hydrophobic monomer repeating unit contains styrene can be mentioned as an example. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described with reference to the accompanying drawings, in which:

[0031] Figure 1 is a micrograph of the filter cake produced by treatment with the candidate antifouling agents mentioned in Example 3. Detailed Description

[0033] In one aspect of the present invention, methods and compositions are provided for inhibiting the formation of polymer-based foulant deposits during alkaline scrubbing of hydrocarbons contaminated with carbonyl compounds which result in the formation of undesirable insoluble polymeric contaminants. In one embodiment, the antifoulant compound is a polymer having formula I

[0034] Formula I

[0035]

[0036] wherein a must be present, and either b or c or both b and c are present; d may or may not be present. In one embodiment, d is present. E is a repeating unit remaining after polymerization of an ethylenically unsaturated compound (including a carboxylic acid such as acrylic acid, sulfonic acid, phosphonic acid, or an amide of such an acid or a mixture thereof); E may be, for example, (meth)acrylic acid or (meth)acrylamide; each R 1 are independently selected from H or lower (C 1 -C 4 ) alkyl. 2 is a hydroxy-substituted alkyl or alkylene moiety having about 1 to 6 carbon atoms, and X is selected from SO 3 、OSO 3 ,PO 3 、OPO 3 or anionic groups of COO; M is one or more hydrogen or any water-soluble cationic moiety that balances the valence of the anionic group X, including but not limited to Na, K, Ca or NH 4 ; F is an ethylenically unsaturated hydrophobic part such as styrene and its derivatives, acrylonitrile, having (C 1 -C 18 )alkyl olefins, alkyl (meth)acrylates.

[0037] Q in the repeating unit c is selected from C 1 -C 3 alkylene or carbonyl; m is 0 or 1, meaning that O may or may not be present, R 3 yes wherein n ranges from about 1 to 100, including 1-20, or R 3 It is a hydroxylated low (C 1 -C 4 ) alkylene such as CH 2 -CH(OH) or CH 2 -CH(OH)-CH 2 ; R 4 It is H, OH, SO 3 M. OSO 3 M.PO3 M. OPO 3 M, C0 2 M or a mixture thereof, wherein M is as defined above.

[0038] In the above formula I, when d is present, it is present in an amount of about 0.01-0.8 moles based on 1 mole of a. One of b or c, or both b or c (if both are present), is present in a monomer ratio of a:b or a:c or a:(b+c) of 0.1-100, including 1-10. The molecular weight of the polymer as set forth in formula I is not critical, as long as the polymer is water soluble or water dispersible. In some embodiments, the molecular weight may range from about 500 to 50,000.

[0039] Exemplary polymers that can be used to inhibit scale in hydrocarbon media containing carbonyl compounds such as aldehydes include acrylic acid / allyl ether copolymers, such as acrylic acid / allyl hydroxylated alkyl copolymers and their water-soluble salt forms, such as acrylic acid / 1-propane sulfonic acid, 2-hydroxy-3 (2-propyleneoxy) monosodium salt, sometimes also referred to as acrylic acid / allyl hydroxypropyl ether sulfonate (AHPSE). In addition, terpolymers containing acrylic acid / AHPSE / and styrene repeating units can also be mentioned.

[0040] Acrylic acid / ethoxylated allyl ethers such as those listed in U.S. Pat. No. 7,094,852 may also be mentioned as examples. These include acrylic acid / allyl polyethoxylated copolymers such as acrylic acid / allyl polyethoxy (10) sulfate (APES) and others. In addition, acrylic acid / allyl polyglycol ethers such as those proposed in U.S. Pat. No. 6,641,754 are also noteworthy. A specific terpolymer of interest is a terpolymer of acrylic acid / AHPSE / and ammonium allyl polyethoxy (10) sulfate.

[0041] Other exemplary polymers may include water-soluble or water-dispersible acrylic acid / hydroxylated alkyl acrylates, such as acrylic acid / 2-hydroxypropyl acrylate copolymers. Certain exemplary polymers are shown in Formula II-V below:

[0042] Formula II

[0043]

[0044] The copolymer shown in Formula II may be referred to as AA / AHPSE (AA as used herein represents acrylic acid and / or its various water-soluble salt forms), and AHPSE has been previously mentioned.

[0045] Formula III

[0046]

[0047] The terpolymer shown in Formula III may be referred to as AA / AHPSE / styrene.

[0048] Formula IV

[0049] This may be referred to as AA / AHPSE / allylpolyethoxy (10) sulfate (APES).

[0050]

[0051] Formula V

[0052] AA / AHPSE / APES / Styrene

[0053]

[0054] The antifoulant polymer can be fed to the alkaline (pH>7) scrubber itself, or to an input or circulation line connected to the scrubber. In some cases, the antifoulant is added to a caustic solution feed or circulation line connected to the scrubber fluid. Typically, the antifoulant polymer is fed to the hydrocarbon stream (feed gas) in an amount of 1-2,000 ppm by weight relative to the hydrocarbon stream. In other embodiments, the antifoulant is fed in an amount of about 1-1,000 ppm. In one embodiment, the feed rate can be about (0.01-100)X of the antifoulant, where X is the molar concentration of the aldehyde or ketone in the feed gas.

[0055] In formula III and IV, a, b and c are independently 0 or a positive integer such that the molecular weight of the molecule is less than about 500,000 Daltons, such as from 500 to 500,000 Daltons. In formula V, a, b, c and d are independently 0 or a positive integer such that the molecular weight of the molecule is less than about 500,000 Daltons.

[0056] In certain aspects of the present invention, the antifouling agent is used in combination with other carbonyl scavengers, which may include alcohol amines such as triisopropanolamine, diglycolamine, aminomethylpropanol, N,N-diethylethanolamine, monoisopropanolamine, monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, etc.; alkyl amines such as phenothiazine, diazacyclohexane, NN-dimethyldodecylamine, N,N′-bis(1-methylpropyl)-1,4-phenylenediamine, aminoethylpiperazine, 1,2-diphenylaminoethane, diethylenetriamine, etc.; ketones Amines, such as triacetoneamine; amino acids, such as 6-aminocaproic acid; hydrazide compounds, such as 1,2-diformylhydrazine, carbohydrazide, N-methyl-hydrazide, oxalyldihydrazide, chlorobenzohydrazide, aminobenzohydrazide, benzohydrazide, etc.; hydroxylamine compounds, such as N,N-diethylhydroxylamine, isopropylhydroxylamine, hydroxylamine sulfate, N,N-dialkylhydroxylamine, etc.; reducing sugars, hydroxybenzenes, acetoacetate compounds, lactams, oxidants such as hydrogen peroxide, peroxy acid esters, percarbonate compounds, etc.; and reducing agents, such as sodium borohydride, sodium (bi)sulfite, etc. These additional compounds may be present in an amount of about 1 to about 2,000 ppm by weight relative to the hydrocarbon stream.

[0057] In another aspect of the present invention, novel water-soluble or water-dispersible polymers are provided that are useful as deposit control, scale inhibition and antifoulant treatments in hydrocarbon media. As an example, these polymers can be used to inhibit carbonyl-based polymer deposits that may otherwise form in alkaline scrubbing systems used in MTO and olefin cracking processes. The antifoulant polymers are generally of formula VI

[0058] Formula VI

[0059]

[0060] Where a, z and d all exist. and As defined above in conjunction with Formula I. G is VIa, VIb, VIc or VId or a mixture thereof, or is one or both of the repeating unit moieties b and c set forth in Formula I, wherein

[0061] VIa is

[0062]

[0063] VIb is

[0064]

[0065] Where R 1 Is H or low (C 1 -C 4 ) alkyl, R 2is a hydroxy-substituted alkyl or alkylene moiety having about 1 to 6 carbon atoms, and X is selected from SO 3 、OSO 3 ,PO 3 、OPO 3 or an anionic group of COO; M is H or hydrogen or any water-soluble cationic moiety that balances the valence of the anionic group X; Q is selected from C 1 -C 3 Alkylene or carbonyl, m is 0 or 1; R 3 yes Where n = 1-100; or R 3 It is a hydroxylated low (C 1 -C 4 ) alkylene; and R 4 It is H, OH, SO 3 M. OSO 3 M.PO 3 M. OPO 3 M or CO 2 M or a mixture thereof, wherein M is as defined above;

[0066] VIc is

[0067]

[0068] Where R 1 As defined above, R 5 is NH or O; R 6 Is low level (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

[0069]

[0070] Where R 7 Yes CH 2 or benzyl, and X and M are as defined above.

[0071] In Formula VI, the molar ratio of d:a is about 0.1-0.8 moles d / 1 mole a; z is present in an a:z amount of 0.1-100 moles a / 1 mole z, with certain embodiments having 1-10 moles a / 1 mole z.

[0072] Exemplary polymers according to Formula VI include acrylic acid (AA) / 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) / styrene terpolymers (ie, Formulas VI and VIc), wherein E is AA, R is 5 Yes NH, R 6= 2-methylpropane, and X is SO 3 - ; F is styrene. In addition, it can be noted that the terpolymer of formula VI is AA / allylsulfonic acid / styrene, wherein R of formula VId is 7 Yes CH 2 , X is SO 3 - In addition, in some embodiments, R 7 May contain a benzyl moiety, where X is SO 3 - , that is, AA / sulfonated styrene / styrene terpolymer.

[0073] In addition, other terpolymer combinations within the scope of Figure VI include AA / AHPSE / styrene terpolymers, AA / lower alkyl (C 1 -C 4 ) acrylate / styrene terpolymer, AA / hydroxylated alkyl (C 1 -C 4 ) acrylate / styrene terpolymer, AA / allyl polyethylene glycol (PEG) ether / styrene terpolymer; AA / allyl polyethoxy sulfate (APES) / styrene terpolymer and AA / PEG allyl ether / APES / styrene polymer.

[0074] The polymers of the present invention can be prepared by free radical chain addition polymerization of the desired monomers. The reaction can be carried out, for example, under conventional solution polymerization techniques. The desired monomers can be mixed with water and alcohol. Polymerization initiators can be used, such as persulfate initiators, peroxide initiators, etc. The resulting copolymers, terpolymers, tetrapolymers, etc. (at least 4 monomer repeating units) can be separated by well-known techniques such as distillation, or the polymers can be simply used in aqueous solution.

[0075] For example, a terpolymer according to formula III can be prepared as follows:

[0076] 1. Charge the initial 97.7 g (sodium 1-allyloxy 2-hydroxypropyl sulfonate) and 50 g DI water into the reactor and set up the reactor

[0077] 2. Record the reactor weight

[0078] 3. Use N 2 Bubble for 10 minutes

[0079] 4. Switch to nitrogen blanket and heat to 90°C

[0080] 5. Start the simultaneous feeding of the following reagents

[0081] 39g acrylic acid, after 1 50 minutes

[0082] 5g styrene, after 60 minutes

[0083] 25g sodium persulfate (5%), for 150 minutes

[0084] 6. After feeding, keep at 90℃ for 90 minutes

[0085] 7. Cool to room temperature and add caustic solution (50% NaOH solution) and dilution water

[0086] 8. Measure reactor weight and solids content.

[0087] In certain aspects of the present invention, a water-soluble terpolymer composition is provided, which comprises: i) acrylic acid or acrylate repeating units, ii) hydrophobic repeating units such as styrene repeating units, and a third repeating unit iii). The third repeating unit can be selected from acrylamide repeating units, allyl ether repeating units, lower alkyl (C 1 -C 4 ) acrylic acid ester repeating units, ethoxylated or propoxylated allyl repeating units, allyl polyethylene glycol ether repeating units, sulfonated styrene repeating units and allyl sulfonic acid repeating units.

[0088] In some cases, the third repeating unit may be 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS). In other cases, the third repeating unit may be allyl hydroxypropyl ether sulfonate (AHPSE). In still other aspects, the third repeating unit may include allyl polyethoxy sulfonate (APES). In addition, in some aspects of the present invention, the third repeating unit may include hydroxypropyl acrylate (HPA). In other embodiments, this third repeating unit may include AHPSE, and a fourth repeating unit may be present. This fourth repeating unit may include APES.

[0089] These terpolymers comprising repeating units i), ii) and iii) may contain about 0.01-0.8 moles of ii) per mole of i) monomer repeating unit. Repeating unit iii) may be present in an amount of about 0.1-10,000, including 1-10 moles of i) per mole of iii). The molecular weight of these polymers may range from about 500 to 500,000. within the range.

[0090] The present invention will be described in conjunction with the following specific examples, which should be considered illustrative and should not be considered to limit the scope of the present invention. Example

[0091] Example 1

[0092] To simulate carbonyl compound fouling in a caustic treatment tower and evaluate the dispersibility and fouling inhibition of candidate compounds, the following procedure was used.

[0093] Table 1: Composition and treatment of simulated carbonyl foulants

[0094]

[0095] 25 ml of 10% NaOH and no dispersant (blank) / 1000 ppm dispersant were placed in a 30 ml glass bottle. The bottle was capped and the solution was mixed. Then 2000 ppm of aldehyde was added to the bottle and mixed after the bottle was capped tightly. Thereafter, the mixture was incubated in a 50°C water bath for 24 hours. Finally, the appearance of the mixture in the bottle was recorded immediately when the bottle was taken out of the water bath without shaking. Thus, untreated samples and samples tested with the candidates listed in Table 2 were tested. The results are shown in Table 3.

[0096] Dispersant / inhibitor candidates were selected. Some of these included known dispersants / inhibitors that are commonly used to control carbonyl-based foulants. These are designated in Table 2 with the prefix "C" (Comparative). Dispersant inhibitor compounds according to the present invention are designated with the prefix "N".

[0097] Table 2: Inhibitor and dispersant candidates

[0098]

[0099] AA = acrylic acid or its salt; poly(AA / AMPS) = poly(acrylic acid / 2-acrylamido-2-methylpropane sulfonic acid); PAA = polyacrylic acid, PMA = polymaleic acid; N 1 = poly(acrylic acid / allyl 2-hydroxypropyl ether sulfonate (AA / AHPSE)); N 2 =Poly(acrylic acid

[0100] / AHPSE / styrene) terpolymer; N3 = poly(AA / AHPSE / allyl polyethoxy (10) sulfate (APES)); N4 = poly(AA / AHPSE / APES / styrene).

[0101] The ability of common dispersants to disperse carbonyl compound fouling in water systems was studied. Carbonyl compound fouling was simulated and treated as in Example 1. The dispersibility of the candidates in Table 2 was studied at a product dosage weight of 1000ppm relative to the total solution. Table 3 shows the test results. From the appearance, the inventors can conclude that C1, C3, C4 and C5 did not show any dispersibility for carbonyl compound fouling at a dosage of 1000ppm. C2 and C6 had some dispersibility for formed fouling. The sample treated with N1 resulted in a uniform suspension with a small amount of precipitation, and no flocs were observed. This indicates that N1 has good dispersibility for polymer fouling caused by carbonyl compounds in the alkali treatment tower, such as aldehydes. N2 showed the best dispersibility without any flocs or precipitation. The hydrophobic monomer in N2 improves its dispersibility.

[0102] Table 3: Carbonyl compound dirt dispersion test results

[0103]

[0104]

[0105] Example 2

[0106] The carbonyl compound soil dispersing performance of C2, N1 and N2 was investigated at a dosage of 500-1000 ppm. Carbonyl compound soil was simulated and treated as in Example 1. The test results are listed in Table 4. From the table, it can be observed that N2 showed the best dispersing ability, and a dosage of 80000 ppm was sufficient to keep the soil suspension stable under laboratory static test conditions.

[0107] Table 4: Carbonyl Compound Dispersion vs. Dosage

[0108]

[0109] Example 3

[0110] The dispersion ability was evaluated by filtration. Carbonyl compound fouling was simulated and treated by a procedure similar to that of Example 1. 200 ml of 10% NaOH was placed in a 500 ml glass bottle, and no treatment (blank) and 1000 ppm of treatment reagents, including Cl, C2 and N2, were added to the bottle. The bottle was capped and shaken. Then 2000 ppm of acetaldehyde was added to the above solution and mixed. Thereafter, the mixture was immediately incubated in a water bath at 50°C for 24 hours. Finally, the bottle was removed, mixed, and the suspension was then filtered through a 0.8 μm glass fiber filter. Figure 1Filter cake showing foulants treated with the corresponding chemicals. After treatment with N2, it can be observed that no fouling material remains on the filter surface. It is shown that the foulant particle size is less than 0.8 μm after treatment with N2. This indicates that N2 has an excellent ability to disperse carbonyl compound foulants into small particles. This ability prevents foulant flocculation or precipitation, thereby eliminating congestion or blockage in caustic treatment trays or pipelines during MTO, ethylene or propylene production processes.

[0111] Although the present invention has been described with respect to its specific embodiments, it is apparent to those skilled in the art that many other forms and modifications of the present invention will be apparent. The appended claims of the present invention should generally be deemed to cover all such obvious forms and modifications, which are within the true spirit and scope of the present invention.

Claims

1. A water-soluble or water-dispersible polymer composition having the following structure Formula VI where a, z and d all exist; It is the repeating unit remaining after the polymerization of acrylic acid or acrylate (AA). is the remaining repeating unit after polymerization of styrene; wherein the molar ratio of d:a is about 0.1-0.8 mole d:1 mole a; z is present in an amount of a:z of 0.1-100 mole a / 1 mole z; is a repeating unit of VIa, wherein VIa is Wherein R1 is H or lower (C1-C4) alkyl, R2 is a hydroxy-substituted alkyl or alkylene moiety having about 1-6 carbon atoms, X is an anionic group selected from SO3 or OSO3; M is H or multiple hydrogens or any water-soluble cationic moiety that balances the valence of the anionic group X.

2. The polymer composition of claim 1 wherein R2 is 2-hydroxypropyl and X is SO3.

3. A water-soluble terpolymer composition comprising acrylic acid or acrylate (AA) repeating units, hydrophobic monomer repeating units comprising styrene, and a third repeating unit selected from allyl ether repeating units, ethoxylated or propoxylated allyl repeating units and allyl sulfonic acid repeating units.

4. The water-soluble terpolymer composition of claim 3, wherein the third repeating unit is allyl hydroxypropyl ether sulfonate (AHPSE).

5. The water-soluble terpolymer composition of claim 4, wherein the fourth repeating unit is present and comprises allyl polyethoxy sulfonate (APES).

6. An antifouling agent comprising a polymer having repeating units characterized by formula III or formula V: Formula III Formula V wherein a, b, c and d are independently positive integers such that the molecular weight of the polymer is less than 500,000 Daltons; X is an anionic group comprising SO3; and M is one or more hydrogen or any water-soluble cationic moiety that balances the valence of the anionic group X.

7. The antifouling agent according to claim 6, further comprising another carbonyl scavenger comprising at least one compound selected from the group consisting of alcoholamines, alkylamines, ketoamines, amino acids, hydrazide compounds, hydroxylamines, reducing sugars, hydroxybenzenes, acetoacetate compounds, lactams, oxidants and reducing agents.

8. A method of inhibiting the formation of fouling materials comprising contacting a hydrocarbon stream containing carbonyl compounds with an antifouling agent and treating the hydrocarbon stream with an alkaline wash solution, wherein the antifouling agent comprises a polymer having repeating units characterized by Formula III or Formula V: Formula III Formula V wherein a, b, c and d are independently positive integers such that the molecular weight of the polymer is less than 500,000 Daltons; X is an anionic group comprising SO3; and M is one or more hydrogen or any water-soluble cationic moiety that balances the valence of the anionic group X.

9. The method of claim 8, wherein the antifouling agent further comprises another carbonyl scavenger, wherein the another carbonyl scavenger comprises at least one compound selected from the group consisting of alcoholamines, alkylamines, ketoamines, amino acids, hydrazide compounds, hydroxylamines, reducing sugars, hydroxybenzenes, acetoacetate compounds, lactams, oxidants and reducing agents.

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