Polymerization inhibitors for high temperature ethylene fractionation systems

Abstract

A process for inhibiting polymerization, colloid formation and fouling in an atypical high temperature ethylene fractionation system, the process comprising treating the atypical high temperature ethylene fractionation system with a composition comprising an effective amount of one or more quinone methide of formula (I), wherein R1, R2 and R3 are independently selected from the group consisting of H,-OH,-SH,-NH2, alkyl, cycloalkyl, heterocycle and aryl; or one or more phenylenediamine, optionally in combination with one or more hindered phenols. # imgabs0 #

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to application serial number 63 / 408,061 filed on September 19, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The disclosed technology relates to compositions and methods for inhibiting polymerization, gum formation and fouling in ethylene fractionation systems. More specifically, the disclosed technology relates to methods for inhibiting polymerization, gum formation and fouling in high temperature ethylene fractionation systems, the methods comprising treating the high temperature ethylene fractionation system with a high temperature stable antifoulant and / or an anti-polymerization composition comprising quinone methide and / or phenylenediamine. Background Art

[0004] Unwanted polymerization, also known as gum formation, can occur in the light hydrocarbon fractionation system of an ethylene plant, leading to fouling, which will negatively impact heat transfer efficiency, fluid flow and product yields, and can result in the production of large amounts of "popcorn polymer". Most units can be effectively treated with conventional inhibitor chemistries such as 4-hydroxyTEMPO (or other stable free radical chemistries), n,n-diethylhydroxylamine (or other hydroxylamines), butylated hydroxytoluene (or other phenolic antioxidants), and combinations thereof.

[0005] However, some units operate at temperatures above typical temperature regimes. These units cannot be treated with traditional inhibitor approaches due to the lack of effectiveness of these traditional actives. Different approaches are needed to inhibit polymerization, gel formation, and scaling in these atypical units. Summary of the invention

[0006] The disclosed technology provides methods for inhibiting polymerization, gum formation and fouling in ethylene fractionation systems using high temperature stable antifoulants and / or anti-polymerization compositions comprising quinone methides and / or phenylenediamines.

[0007] Various aspects of the present disclosure are directed to a high temperature stable composition for inhibiting polymerization in a high temperature ethylene fractionation system, the high temperature stable composition comprising:

[0008] An effective amount of one or more quinone methides of the formula:

[0009]

[0010] Where R 1 , R 2 and R 3 independently selected from the group consisting of: H, -OH, -SH, -NH 2, alkyl, cycloalkyl, heterocyclic and aryl groups; and an effective amount of one or more phenylenediamines, such as unsymmetrical phenylenediamine.

[0011] In various aspects, the high temperature stable antifouling agent or anti-polymerization composition further comprises one or more hindered phenols.

[0012] Various aspects of the present disclosure additionally relate to a method of inhibiting polymerization in an ethylene fractionation system, the method comprising adding an effective amount of one or more quinone methides of the formula:

[0013]

[0014] Where R 1 , R 2 and R 3 independently selected from the group consisting of: H, -OH, -SH, -NH 2 , alkyl, cycloalkyl, heterocycle-, and aryl.

[0015] In various aspects of the disclosed method, the method further comprises adding an effective amount of one or more phenylenediamines.

[0016] In various aspects of the disclosed method, the method further comprises adding an effective amount of one or more hindered phenols.

[0017] Various aspects of the present disclosure further relate to a method of inhibiting gum formation and fouling in a high temperature ethylene fractionation system, the method comprising: adding an effective amount of one or more quinone methides of the formula:

[0018]

[0019] Where R 1 , R 2 and R 3 independently selected from the group consisting of: H, -OH, -SH, -NH 2 , alkyl, cycloalkyl, heterocyclic and aryl.

[0020] In various aspects of the disclosed method, the method further comprises adding an effective amount of one or more phenylenediamines.

[0021] In various aspects of the disclosed method, the method further comprises adding an effective amount of one or more hindered phenols. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Those skilled in the art will appreciate that the drawings described below are for illustration purposes only and are not intended to limit the scope of the present teachings in any way.

[0023] Figure 1Shown is the reduction in gum formation in liquid samples derived from a synthetic matrix consisting of 50% isoprene and 50% n-heptane after treatment with 20 ppm doses of various polymerization inhibitor chemistries, including various embodiments of the compositions of the disclosed technology.

[0024] Figures 2A to 2C The results are shown after treatment with various polymerization inhibitor chemistries at 20 ppm, including various heat-stressed and non-heat-stressed embodiments of the compositions of the disclosed technology, and at N 2 Purge (complete removal of O 2 ) and N 2 Cover (to retain dissolved O 2 ) under the conditions of 50% isoprene and 50% n-heptane.

[0025] Figure 3 The reduction of gum formation in liquid samples derived from a synthetic matrix composed of 50% isoprene and 50% n-heptane after treatment with 10 ppm or 20 ppm of various polymerization inhibitor chemicals, including various embodiments of the compositions of the disclosed technology, is shown. DETAILED DESCRIPTION

[0026] As used herein throughout the specification and claims, approximate language can be used to modify any quantitative representation that can allow variation without causing a change in the basic function to which it is related. Therefore, the value modified by one or more terms (such as "about") is not limited to the specified exact value. In at least some examples, approximate language may correspond to the accuracy of the instrument used to measure the value. Range limitations can be combined and / or interchangeable, and unless the context or language indicates otherwise, such ranges are identified and include all sub-ranges described herein. Except in the operating examples or when otherwise indicated, all other cases, all numbers or expressions referring to the quantity, reaction conditions, etc. of the components used in this specification and claims should be understood to be modified by the term "about" in all cases.

[0027] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, or the subsequently identified material may or may not exist, and that the description includes instances where the event or circumstance occurs or the material is present and instances where it does not occur or the material does not exist.

[0028] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0029] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0030] The disclosed technology provides compositions and methods for inhibiting polymerization, gum formation, and fouling in ethylene fractionation systems, wherein the compositions comprise quinone methides and / or phenylenediamines.

[0031] It has been found that the compositions and methods disclosed herein are effective in reducing undesirable polymerization, colloid formation and fouling in ethylene fractionation systems. More specifically, it has been found that the compositions and methods disclosed herein are effective in reducing undesirable polymerization, colloid formation and fouling in atypical high temperature ethylene fractionation systems by applying high temperature stable active agents (such as quinone methide and / or phenylenediamine, optionally in combination with hindered phenols). Without being bound by theory, it is believed that adding one or more high temperature stable actives to atypical high temperature ethylene fractionation systems can inhibit free radical polymerization. It is believed that quinone methide actives can react with any thermally generated carbon-centered free radicals, while phenylenediamine actives can interact with thermally generated oxygen-centered free radicals, and / or terminate alkyl radicals in the system. It is further believed that optional hindered phenol actives can increase the reaction rate of quinone methide actives with carbon-centered free radicals.

[0032] As used herein, the term "ethylene fractionation system" refers to the portion of an ethylene plant that includes one or more fractionators.

[0033] As used herein, the term "high temperature ethylene fractionation system" refers to an ethylene fractionation system that operates at relatively high temperatures, such as between about 120°C and 160°C.

[0034] As used herein, the term "effective amount" refers to any amount of the high temperature stabilization active agent that is effective in inhibiting polymerization, gum formation, and fouling in an ethylene fractionation system.

[0035] In various aspects of the disclosed technology, a high temperature stable composition for suppressing polymerization, colloid formation and fouling in an ethylene fractionation system is disclosed. In various aspects, the high temperature stable composition may include an effective amount of one or more high temperature stable active agents. In some aspects, the high temperature stable composition may include a certain amount of any high temperature stable active agent effective in suppressing polymerization, colloid formation and fouling in an ethylene fractionation system. In other aspects, the high temperature stable active agent may be included in any active agent effective in suppressing free radical polymerization in a high temperature ethylene fractionation system.

[0036] In various aspects, suitable high temperature stable active agents may comprise quinone methides of formula (I):

[0037]

[0038] Where R 1 , R 2 and R 3 independently selected from the group consisting of: H, -OH, -SH, -NH 2 , alkyl, cycloalkyl, heterocyclic and aryl; alkyl-(3,5-di-tert-butyl-4-oxocyclohexane-2,5-dienylidene)-cyano derivatives of quinone methide; alkyl-(3,5-di-tert-butyl-4-oxocyclohexane-2,5-dienylidene)-acid derivatives of quinone methide; alkyl-(3,5-di-tert-butyl-4-oxocyclohexane-2,5-dienylidene)-ester derivatives of quinone methide; 2,6-di-tert-butyl-4-(4-nitrobenzylidene)-cyclohexane-2,5-dienone; di-tert-butyl-3-(4-nitrobenzylidene)-cyclohexane -2,5-dienonone; 2,6-di-tert-butyl-4-(4-cyanobenzylidene)-cyclohexa-2,5-dienonone; 2,6-di-tert-butyl-4-(4-methoxybenzylidene)-cyclohexa-2,5-dienonone; 2,6-di-tert-butyl-4-(3,5-di-tert-butyl-4-hydroxybenzylidene)-cyclohexa-2,5-dienonone; 2-(3,5-di-tert-butyl-4-oxocyclohexa-2,5-diene-1-ylidene)acetonitrile; 2,6-di-tert-butyl-4-(methoxymethylene)cyclohexa-2,5-dienonone; phenylenediamine; hindered phenols; and combinations thereof.

[0039] In various aspects, the high temperature stable composition can include one or more quinone methides of formula (I) and one or more phenylenediamines.

[0040] In various aspects, the high temperature stable composition can include one or more quinone methides of formula (I), one or more phenylenediamines, and one or more hindered phenols.

[0041] In various aspects, suitable quinone methides may include 4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5-dienone of formula (II):

[0042]

[0043] In various aspects, suitable phenylenediamines can include asymmetric phenylenediamines such as N-(1,4-dimethylpentyl)-N-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, or combinations thereof.

[0044] In various aspects, suitable hindered phenols may include 2,6-di-tert-butylphenol, butylated hydroxytoluene; butylated hydroxyanisole; 2,4,6-tri-tert-butylphenol; 4,4'-methylenebis[2,6-bis(2-methyl-2-propyl)phenol]; or combinations thereof.

[0045] In various aspects, the high temperature stable active agent can be present in an amount between about 0.1 ppm and about 10000 ppm, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 , 600, 650, 700, 750, 800, 850, 900, 950, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or 10000 ppm, or an amount between about 0.1 ppm to about 50 ppm, or between about 20 ppm to about 40 ppm, or any amount between any of these values ​​is present in the composition.

[0046] In various aspects, the high temperature stable composition can include one or more quinone methides of formula (I) and one or more phenylenediamines in a ratio between about 1:1 and 1:100, or 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100, or between about 1:2 and 1:10; or any ratio between any of these ratios.

[0047] In various aspects, the high temperature stable active agents of the disclosed technology can be used in methods for inhibiting polymerization in ethylene fractionation systems. In various aspects, the high temperature stable active agents can be further used in methods for inhibiting colloid formation and fouling in high temperature ethylene fractionation systems. In various aspects, the method can include adding an effective amount of one or more high temperature stable active agents to the ethylene fractionation system.

[0048] In various aspects, the method can include adding to the ethylene fractionation system an effective amount of one or more quinone methides selected from the group consisting of: Quinone methides of formula (I):

[0049]

[0050] Where R 1 , R 2 and R 3 independently selected from the group consisting of: H, -OH, -SH, -NH 2 , alkyl, cycloalkyl, heterocyclic and aryl; alkyl-(3,5-di-tert-butyl-4-oxocyclohexane-2,5-dienylidene)-cyano derivatives of quinone methides; alkyl-(3,5-di-tert-butyl-4-oxocyclohexane-2,5-dienylidene)-acid derivatives of quinone methides; alkyl-(3,5-di-tert-butyl-4-oxocyclohexane-2,5-dienylidene)-ester derivatives of quinone methides; 2,6-di-tert-butyl-4-(4-nitrobenzylidene)-cyclohexa-2,5-dienone; di-tert-butyl-3-(4-nitrobenzylidene)-cyclohexa-2,5-dienone; enone; 2,6-di-tert-butyl-4-(4-cyanobenzylidene)-cyclohexa-2,5-dienonone; 2,6-di-tert-butyl-4-(4-methoxybenzylidene)-cyclohexa-2,5-dienonone; 2,6-di-tert-butyl-4-(3,5-di-tert-butyl-4-hydroxybenzylidene)-cyclohexa-2,5-dienonone; 2-(3,5-di-tert-butyl-4-oxocyclohexa-2,5-diene-1-ylidene)acetonitrile; 2,6-di-tert-butyl-4-(methoxymethylene)cyclohexa-2,5-dienonone; or one or more phenylenediamines; one or more hindered phenols; or a combination thereof.

[0051] In various aspects, the method can include adding an effective amount of one or more quinone methides of formula (I) and an effective amount of one or more phenylenediamines to an ethylene fractionation system.

[0052] In various aspects, the method can include adding an effective amount of one or more quinone methides of formula (I), an effective amount of one or more phenylenediamines, and an effective amount of one or more hindered phenols to an ethylene fractionation system.

[0053] In various aspects, suitable quinone methides may include 4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5-dienone of formula (II):

[0054]

[0055] In various aspects, suitable phenylenediamines can include asymmetric phenylenediamines such as N-(1,4-dimethylpentyl)-N-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, or combinations thereof.

[0056] In various aspects, suitable hindered phenols may include 2,6-di-tert-butylphenol, butylated hydroxytoluene; butylated hydroxyanisole; 2,4,6-tri-tert-butylphenol; 4,4'-methylenebis[2,6-bis(2-methyl-2-propyl)phenol]; or combinations thereof.

[0057] In various aspects of the methods of the disclosed technology, the high temperature stable active agent can be used at a concentration of between about 0.1 ppm and about 10000 ppm, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, , 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or 10000 ppm, or in an amount between about 0.1 ppm to about 50 ppm, or between about 20 ppm to about 40 ppm, or any amount between any of these values ​​is added to the ethylene fractionation system.

[0058] In various aspects, the method can include adding one or more quinone methides of formula (I) and one or more phenylenediamines in a ratio between about 1:1 and 1:100, or 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100, or about 1:2 to 1:10; or any ratio between any of these ratios.

[0059] Examples

[0060] The present technology will be further described in the following examples, which should be regarded as illustrative and should not be construed to narrow the scope of the disclosed technology or to limit the scope to any particular embodiment.

[0061] Example 1

[0062] Exemplary Inhibitor Chemistry:

[0063] BHT-2,6-di-tert-butylphenol

[0064] PDA-1-N,N'-di-sec-butyl-p-phenylenediamine

[0065] PDA-2-N-(1,4-dimethylpentyl)-N-phenyl-p-phenylenediamine

[0066] QM-4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5-dienone and 2,6-di-tert-butylphenol.

[0067] The heat-induced colloid test was conducted on a synthetic matrix consisting of 50% isoprene (stock inhibitor removed) and 50% n-heptane. The heat-induced colloid test consisted of treating the sample with 10 ppm or 20 ppm of the above listed inhibitor chemistries (or mixtures thereof), placing the sample in an autoclave, blanketing or purging the sample with 400 psig nitrogen (3x), and then placing the sample in a heated oil bath for 4 hours. The oil bath was heated to 140°C to represent the high temperature operating conditions to be treated. After heating for 4 hours, the autoclave was cooled, vented, and the liquid sample was removed.

[0068] The liquid sample is then transferred to a pre-weighed beaker and placed in a block heater. The nitrogen stream of heating is directed directly to the liquid top, with the purpose of forcing the liquid phase to evaporate. If any polymer (colloid) is formed during the 4 hour heating phase, after the liquid evaporates, it will stay in the beaker. After 30 minutes, the beaker is cooled and weighed. The amount of the quantitative colloid in mg / 100mL is then taken.

[0069] like Figure 1 and 3 As shown, among the various inhibitor chemistries tested, the addition of QM-based / PDA-2 and QM-based / PDA-2 / BHT mixtures to the samples resulted in significantly lower colloid formation compared to the untreated samples and the other chemistries.

[0070] In addition, if Figures 2A to 2C As shown, in the absence of O 2 (3xN 2 Purge) and low O 2 (N 2 Under both conditions (covered), the addition of QM-based and QM-based / PDA-2 mixtures to the samples resulted in significantly lower colloid formation compared to untreated samples as well as heat stress inhibitor chemistries.

[0071] Although embodiments of the disclosed technology have been described, it should be understood that the disclosure is not limited thereto and can be modified without departing from the disclosed technology. The scope of the disclosed technology is defined by the appended claims, and it is intended that all devices, processes and methods within the meaning (literally or equivalently) of the claims are covered.

Claims

1. A high temperature stable composition for inhibiting polymerization in a high temperature ethylene fractionation system, the high temperature stable composition comprising: An effective amount of one or more quinone methides of the formula: Where R 1 , R 2 and R 3 are independently selected from the group consisting of: H, -OH, -SH, -NH2, alkyl, cycloalkyl, heterocycle, and aryl; and An effective amount of one or more phenylenediamines.

2. The high temperature stable composition according to claim 1, further comprising one or more hindered phenols.

3. The high temperature stable composition of claim 1, wherein the one or more quinone methides include 4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5-dienone of formula (II):

4. The high temperature stable composition of claim 1, wherein the one or more phenylenediamines comprises an asymmetric phenylenediamine.

5. The high temperature stable composition according to claim 4, wherein the asymmetric phenylenediamine is N-(1,4-dimethylpentyl)-N-phenyl-p-phenylenediamine.

6. The high temperature stable composition of claim 2, wherein the one or more hindered phenols comprises 2,6-di-tert-butylphenol.

7. The high temperature stable composition of claim 1, wherein the composition comprises the one or more quinone methides in an amount between about 1 ppm and about 10,000 ppm.

8. The high temperature stable composition of claim 7, wherein the composition comprises the one or more quinone methides in an amount between about 10 ppm and about 40 ppm.

9. The high temperature stable composition of claim 1, wherein the composition comprises the one or more phenylenediamines in an amount between about 1 ppm and about 10,000 ppm.

10. The high temperature stable composition of claim 9, wherein the composition comprises the one or more phenylenediamines in an amount between about 10 ppm and about 40 ppm.

11. The high temperature stable composition of claim 2, wherein the composition comprises the one or more hindered phenols in an amount between about 0.1 ppm and about 10,000 ppm.

12. The high temperature stable composition of claim 11, wherein the composition comprises the one or more hindered phenols in an amount between about 0.1 ppm and about 40 ppm.

13. A method for inhibiting polymerization in an ethylene fractionation system, the method comprising: Add an effective amount of one or more quinone methides of the formula: Where R 1 , R 2 and R 3 Independently selected from the group consisting of H, -OH, -SH, -NH2, alkyl, cycloalkyl, heterocycle, and aryl.

14. The method of claim 13, further comprising adding an effective amount of one or more phenylenediamines.

15. The method of claim 13 or 14, further comprising adding an effective amount of one or more hindered phenols.

16. The method of claim 13, wherein the one or more quinone methides include 4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5-dienone of formula (II):

17. The method of claim 14, wherein the one or more phenylenediamines comprises an asymmetric phenylenediamine.

18. The method of claim 17, wherein the asymmetric phenylenediamine is N-(1,4-dimethylpentyl)-N-phenyl-p-phenylenediamine.

19. The method of claim 15, wherein the one or more hindered phenols comprises 2,6-di-tert-butylphenol.

20. The method of claim 13, wherein the method comprises adding the one or more quinone methides in an amount between about 1 ppm and about 10,000 ppm.

21. The method of claim 20, wherein the method comprises adding the one or more quinone methides in an amount between about 10 ppm and about 40 ppm.

22. The method of claim 14, wherein the method comprises adding the one or more phenylenediamines in an amount between about 1 ppm and about 10,000 ppm.

23. The method of claim 22, wherein the method comprises adding the one or more phenylenediamines in an amount between about 10 ppm and about 40 ppm.

24. The method of claim 15, wherein the method comprises adding the one or more hindered phenols in an amount between about 0.1 ppm and about 10,000 ppm.

25. The method of claim 24, wherein the method comprises adding the one or more hindered phenols in an amount between about 0.1 ppm and about 40 ppm.

26. The process of claim 13, wherein the ethylene fractionation system operates at an elevated temperature of about 120°C to about 160°C.

27. The method of claim 13, wherein the polymerization is a free radical polymerization.

28. A method for inhibiting gum formation and fouling in a high temperature ethylene fractionation system, the method comprising: Add an effective amount of one or more quinone methides of the formula: Where R 1 , R 2 and R 3 Independently selected from the group consisting of H, -OH, -SH, -NH2, alkyl, cycloalkyl, heterocycle, and aryl.

29. The method of claim 28, further comprising adding an effective amount of one or more phenylenediamines.

30. The method of claim 28, further comprising adding an effective amount of one or more hindered phenols.

31. The method of claim 28, wherein the one or more quinone methides include 4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5-dienone of formula (II):

32. The method of claim 29, wherein the one or more phenylenediamines comprises an asymmetric phenylenediamine.

33. The method of claim 32, wherein the asymmetric phenylenediamine is N-(1,4-dimethylpentyl)-N-phenyl-p-phenylenediamine.

34. The method of claim 30, wherein the one or more hindered phenols comprises 2,6-di-tert-butylphenol.

35. The method of claim 28, wherein the method comprises adding the one or more quinone methides in an amount between about 1 ppm and about 10,000 ppm.

36. The method of claim 35, wherein the method comprises adding the one or more quinone methides in an amount between about 10 ppm and about 40 ppm.

37. The method of claim 29, wherein the method comprises adding the one or more phenylenediamines in an amount between about 1 ppm and about 10,000 ppm.

38. The method of claim 37, wherein the method comprises adding the one or more phenylenediamines in an amount between about 10 ppm and about 40 ppm.

39. The method of claim 30, wherein the method comprises adding the one or more hindered phenols in an amount between about 0.1 ppm and about 10,000 ppm.

40. The method of claim 39, wherein the method comprises adding the one or more hindered phenols in an amount between about 0.1 ppm and about 40 ppm.

41. The process of claim 28, wherein the ethylene fractionation system is operated at a temperature of about 120°C to about 160°C.

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