WO2015183641A1

WO2015183641A1 - Effluent cooler in the manufacture of acrylonitrile

Info

Publication number: WO2015183641A1
Application number: PCT/US2015/031673
Authority: WO
Inventors: Timothy Robert Mcdonel; Jay Robert COUCH; David Rudolph Wagner; Paul Trigg Wachtendorf
Original assignee: Ineos Europe Ag
Priority date: 2014-05-26
Filing date: 2015-05-20
Publication date: 2015-12-03
Also published as: JP2017518988A; EA201692323A1; CN103968689A; TW201546413A

Abstract

A process comprises recovering heat from reactor effluent, the reactor effluent comprising acrylonitrile or methacrylonitrile from an ammoxidation reactor. The recovering comprises heat exchange with feed water in an effluent cooler, wherein the recovering of heat occurs prior to the reactor effluent being quenched in a quench column. The process comprises shielding metal of the effluent cooler with metal shrouds at inlets of heat exchanger tubes of the effluent cooler. The process comprises online cleaning of fouling from components of the reactor effluent that accumulate on the metal shrouds, wherein the online cleaning comprises conveying scouring particles to the metal shrouds. In an aspect, the metal shroud protects the inlets of the effluent cooler from erosion during online cleaning that would otherwise occur at the inlets without the metal shroud.

Description

EFFLUENT COOLER IN THE MANUFACTURE OF ACRYLONITRILE

FIELD OF THE INVENTION

[1] The disclosure relates to an improved process in the manufacture of acrylonitrile and methacrylonitrile. In particular, the disclosure is directed to an improved effluent cooler for recovery of heat from reactor effluent.

BACKGROUND

[2] Various processes and systems for the manufacture of acrylonitrile and methacrylonitrile are known; see for example, U.S. Patent No. 6,107,509. Typically, recovery and purification of acrylonitrile/methacrylonitrile produced by the direct reaction of a hydrocarbon selected from the group consisting of propane, propylene or isobutylene, ammonia and oxygen in the presence of a catalyst has been accomplished by transporting the reactor effluent containing acrylonitrile/methacrylonitrile to a first column (quench) where the reactor effluent is cooled with a first aqueous stream, transporting the cooled effluent containing acrylonitrile/methacrylonitrile into a second column (absorber) where the cooled effluent is contacted with a second aqueous stream to absorb the acrylonitrile/methacrylonitrile into the second aqueous stream, transporting the second aqueous stream containing the acrylonitrile/methacrylonitrile from the second column to a first distillation column (recovery column) for separation of the crude acrylonitrile/methacrylonitrile from the second aqueous stream, and transporting the separated crude acrylonitrile/methacrylonitrile to a second distillation column (heads column) to remove at least some impurities from the crude acrylonitrile/ methacrylonitrile, and transporting the partially purified acrylonitrile/methacrylonitrile to a third distillation column (product column) to obtain product acrylonitrile/methacrylonitrile. U.S. Pat. Nos. 4,234,510; 3,936,360; 3,885,928; 3,352,764; 3,198,750 and 3,044,966 are illustrative of typical recovery and purification processes for acrylonitrile and methacrylonitrile.

[3] While the manufacture of acrylonitrile/methacrylonitrile has been commercially practiced for years there are still areas in which improvement would have a substantial benefit. One of those areas of improvement would be efficient heat recovery from reactor effluent and efficient pre-cooling of reactor effluent before the reactor effluent is conveyed to a quench column.

SUMMARY

[4] Accordingly, an aspect of the disclosure is to provide a safe, effective and cost effective process and apparatus that overcomes or reduces the disadvantages of conventional processes.

[5] In an aspect, a process comprises recovering heat from reactor effluent, the reactor effluent comprising acrylonitrile or methacrylonitrile from an ammoxidation reactor, wherein the recovering comprises heat exchange between the reactor effluent and water in an effluent cooler. The process comprises shielding metal of the effluent cooler with metal shrouds at inlets of heat exchanger tubes of the effluent cooler. The process comprises online cleaning of fouling from components of the reactor effluent that accumulate on the metal shrouds. In an aspect, the online cleaning comprises conveying scouring particles to the metal shrouds. In an aspect, the metal shroud shields the inlets of the effluent cooler from erosion during the online cleaning that would otherwise occur at the inlets without the metal shroud.

[6] The above and other aspects, features and advantages of the present disclosure will be apparent from the following detailed description of the illustrated embodiments thereof which are to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[7] A more complete understanding of the exemplary embodiments of the present disclosure and the advantages thereof may be acquired by referring to the following description in consideration of the accompanying drawings in which like reference numbers indicate like features and wherein: [8] FIG. 1 is a schematic flow diagram of an embodiment in accordance with aspects of the disclosure as applied to the manufacture of acrylonitrile product.

[9] FIG. 2 illustrates an effluent cooler in accordance with aspects of the disclosure.

[10] FIG. 3 illustrates an embodiment in accordance with aspects of the disclosure.

[11] FIG. 4 illustrates a flow diagram of a process in accordance with aspects of the disclosure.

DETAILED DESCRIPTION

[12] In an aspect, a process is provided relating to the recovery and purification of acrylonitrile or methacrylonitrile from an ammoxidation reactor effluent containing acrylonitrile or methacrylonitrile, acetonitrile and heavy organic impurities. It has been found that heat may be recovered from reactor effluent through heat exchange with boiler feed water in an effluent cooler, wherein the recovering heat occurs prior to the reactor effluent being quenched in a quench column. It has been found, however, that fouling from components of rector effluent may occur at the effluent cooler. It has been found that components of reactor effluent that may cause fouling at the effluent cooler may comprise polymer and/or molybdenum. It has been found that the effluent cooler may need to be taken out of service as frequently as every 1-3 months to physically clean the fouling at the effluent cooler.

[13] In an aspect, a process is provided that may comprise online cleaning of the effluent cooler of fouling from components of the reactor effluent, wherein the online cleaning comprises conveying scouring particles to remove fouling in an effluent cooler. In an aspect, the scouring particles may comprise a scouring agent selected from the group consisting of ammonium sulfate ("AMS"), sand, and combinations thereof. AMS is present in the quench column downstream of the effluent cooler, and thus the addition of AMS to reactor effluent during online cleaning of the reactor cooler is acceptable for operation of the quench column receiving the reactor effluent from the effluent cooler. In this aspect, the AMS utilized may have an average particle size of about 1 to about 5 mm, and in another aspect, about 1 to about 3 mm.

[14] In an aspect, the conveying of the scouring particles may occur at any suitable frequency, rate, pressure, and period of time. In an aspect, the conveying of the scouring particles may occur about every three (3) to eleven (11) days that the effluent cooler is in operation to recover heat from reactor effluent. In an aspect, the conveying of the scouring particles may occur about every five (5) to nine (9) days that the effluent cooler is in operation to recover heat from reactor effluent. In an aspect, the conveying of the scouring particles may occur about every six (6) to eight (8) days that the effluent cooler is in operation to recover heat from reactor effluent. In an aspect, the conveying of the scouring particles may occur about every seven (7) days that the effluent cooler is in operation to recover heat from reactor effluent.

[15] In an aspect, the conveying the scouring particles to the inlet tube sheet of the effluent cooler may be in a velocity range of about 0.5 meters/second to about 1 meter/second. In an aspect, the conveying of scouring to particles the inlet tube sheet of the effluent cooler may be for a duration of about three (3) seconds to about thirty (30) minutes, in another aspect, about three (3) seconds to about fifteen (15) minutes, in another aspect, about three (3) seconds to about five (5) minutes, in another aspect, about three (3) seconds to about one (1) minute, in another aspect, about five (5) seconds to about thirty (30 ) seconds, in another aspect, about five (5) seconds to about ten (10) seconds, in another aspect, greater than about two (2) minutes to about thirty (30) minutes, in another aspect, greater than about two (2) minutes to about fifteen (15) minutes, in another aspect, greater than about two (2) minutes to about ten (10) minutes, in another aspect, greater than about two (2) minutes to about five (5) minutes, in another aspect, about two and one-half minutes (2.5) to about thirty (30) minutes, in another aspect, about three (3) to about fifteen (15) minutes, and in another aspect, about three (3) to about five (5) minutes. [16] In another aspect, when AMS is utilized, the AMS is conveyed in an amount of about 0.025 to about 0.10 kg per square meter of tube sheet of the effluent cooler, and in another aspect, about 0.025 to about 0.075 kg per square meter of tube sheet of the effluent cooler. In another aspect, the process uses about 0.0002 kg to about 0.00075 kg of AMS per metric ton of acrylonitrile produced, and in another aspect, about 0.0003 to about 0.006 kg of AMS per metric ton of acrylonitrile produced.

[17] In an aspect, the scouring particles may be conveyed from a scouring particle source through a line and through a nozzle. In an aspect, the conveying of the scouring particles may performed by conveying the scouring particles through one or more nozzles. In an aspect, the nozzles may be full cone spray nozzles. In an aspect, the nozzles may be placed so that the nozzle outlets are about 1.0 - 3.0 meters from the inlets of the tubes or inlet tube sheet of the effluent cooler. In an aspect, the nozzle outlets may be about 1.5 - 2.5 meters from the inlets of the tubes or inlet tube sheet of the effluent cooler. In an aspect, the nozzle outlets may be about 1.5 - 2.0 meters from the inlets of the tubes or inlet tube sheet of the effluent cooler. In an aspect, the nozzle outlets may be about 2.0 meters from the inlets of the tubes or inlet tube sheet of the effluent cooler.

[18] In an aspect, the scouring particles may be conveyed to the inlet tube sheet, and metal between the inlets of the effluent cooler, and tube welds.

[19] In an aspect, the spraying of scouring particles to the inlet tube sheet may allow for flushing of accumulations of foulants, e.g., polymer and/or molybdenum, that may have collected at or on the inlet tube sheet or at the inlet of tubes of the effluent cooler. By removing these foulants while the effluent cooler is in operation, sustained operation of the effluent cooler may be achieved for extended periods of time of up to at about 18 months, in another aspect, about six (6) months without having to take the effluent cooler out of service for foulant cleaning. This extended period of time of up to about 18 months for foulant cleaning of the effluent cooler is much longer than a process devoid of the above described online conveying of scouring particles. It has been found that without the above described conveying of scouring particles to fouling in the effluent cooler, an effluent cooler may need to be taken out of service about every 1-3 months for foulant cleaning, e.g., foulant cleaning of the inlet tube sheet of the effluent cooler, including foulant cleaning of the inlet tube sheet and about six (6) inches into tubes of the effluent cooler.

[20] In an aspect, spray angles for the full cone spray nozzles may be between about 30 and 90 degrees, and in another aspect, about 70 degrees to prevent excessive deflection of the scouring particles spray pattern applied to the effluent cooler.

[21] It has been found that the conveying of the scouring particles to the inlet tube sheet may erode metal of the effluent cooler, particularly at the inlets of the tubes of the effluent cooler. The erosion may extend up to about six inches from the inlets of the tubes into the tubes. In an aspect of the disclosure, a metal shroud is provided to shield metal of the effluent cooler from the scouring particles, thereby eliminating or reducing erosion of the metal of the effluent cooler. In an aspect, it has been found that use of a metal shroud allows for the conveying of the scouring particles to be intensified, i.e., made at higher flow rates, and/or greater pressure, and/or more frequently, and/or for longer periods of time, with less or no risk of erosion of the metal of the effluent cooler. In an aspect, it has been found that use of a metal shroud allows for greater flexibility to convey the scouring particles with less or no risk of erosion of the metal of the effluent cooler. Due to the above greater flexibility to convey the scouring particles, it has been found that, in an aspect, greater flexibility in operation of the reactor, effluent cooler, and/or quench column may also be provided. For example, effluent cooler operation may be adjusted to increase or decrease the spraying of the scouring particles when the reactor is operated in manner that produces increased or decreased polymer in the reactor effluent that may cause fouling in the effluent cooler. Any increased fouling from the increased polymer may be removed by conveying the scouring particles at higher flow rates, and/or greater pressure, and/or more frequently, and/or for longer periods of time, with less or no risk of erosion of the metal of the effluent cooler. An increase in pressure at inlets of the effluent cooler tubes may be an indication of fouling at the inlets. When the pressure at the inlets of the effluent cooler tubes is outside a predetermined range, the conveying of the scouring particles may be adjusted accordingly. The more heat recovery from the reactor effluent that occurs in the effluent cooler, the less heat transfer that would be needed in the quench column that would otherwise be required.

[22] The apparatus and method of the present disclosure will now be described in further detail with reference to the figures.

[23] FIG. 1 is a schematic flow diagram of an embodiment in accordance with aspects of the disclosure as applied to the manufacture of acrylonitrile product. Apparatus 100 may comprise reactor 10. Reactor 10 may be configured to receive ammonia and propylene and generate reactor effluent 12. Reactor effluent 12 may be conveyed via line 14 to effluent cooler 16.

[24] Effluent cooler 16 may comprise inlet tube sheet 18, heat exchanger tubes 20, and shell (not shown). Each heat exchanger tube 20 may comprise a corresponding inlet 24. Boiler feed water 26 may be conveyed to shell inlet 28 and exit from shell outlet 30. Effluent cooler 16 may be configured to allow for heat transfer from reactor effluent 12 to boiler feed water 26. Reactor effluent 12 may have a first temperature at tube inlets 24, and a second temperature at tube outlets 32. In an aspect, the first temperature of reactor effluent 12 at tube inlets 24 is higher than the second temperature of reactor effluent 12 at tube outlets 32. In an aspect, the temperature of the boiler feed water at shell inlet 28 is lower than the temperature of the boiler feed water exiting from shell outlet 30.

[25] In an aspect, scouring particles 34 may be conveyed from scouring particles source 36 via line 38 to nozzles 40. Nozzles 40 may be full cone spray nozzles. The flow of scouring particles 34 may be controlled by controller 42. Controller 42 may be configured to control, e.g., via communications lines or wireless communications (not shown in FIG. 1), the operation of valve 46. Apparatus 100 may be configured to convey scouring particles 34 through nozzles 40 to clean or remove foulants. [26] Controller 42 may be configured to adjust operation of one or more devices via communication lines or wireless communications (not shown in FIG. 1) if a measured parameter is below or above a predetermined parameter range. Those skilled in the art will recognize that in accordance with the disclosure, controller 42 may be configured to control operation of pumps and/or valves associated with the flow of fluids in order to meet the predetermined parameter range. Those skilled in the art will recognize that in accordance with the disclosure, controller 42 may be configured to control operation of other controllers, such as flow controllers in order to meet a predetermined parameter or range.

[27] FIG. 2 is a top perspective view of inlet tube sheet 18 in accordance with aspects of the disclosure. Inlet tube sheet 18 may comprise a plurality of tube inlets 24. In an aspect, each tube inlet 24 may comprise a corresponding metal shroud 48. Metal shroud 48 may comprise ferrule 50. Metal shroud 48 may be configured to protect tube inlets 24 and inlet tube sheet 18 from erosion of metal of the tube inlets 24 and inlet tube sheet 18 that may otherwise occur when scouring particles 34 is sprayed from nozzles 40. Metal shroud 48 may comprise any suitable metal having shielding characteristics, including but not limited to seamless cold-drawn intermediate alloy-steel, e.g., SA-199 Grade Ti l (ASME standard).

[28] It has been found that by providing metal shrouds and using larger tubes, the opening or open area to receive fluid may be maintained. Those skilled in the art will recognize that in accordance with the disclosure the spraying of scouring particles to the inlet tube sheet will allow for removal of any small accumulations of foulants, e.g., polymer and/or molybdenum, that have collected at or on the inlet tube sheet or at the inlet of tubes of the effluent cooler. By removing these foulants while the effluent cooler is in operation, and using flared or fluted opening, sustained operation of the effluent cooler may be achieved for extended periods of time of up to at least about eighteen (18) months without having to take the effluent cooler out of service for foulant cleaning. This extended period of time of up to at least about eighteen (18) months for foulant cleaning of the effluent cooler is much longer than a process devoid of the above described online conveying of scouring particles and shielding with metal shrouds that provides a flared or fluted opening. It has been found that without the above described shielding using metal shrouds, even with conveying of scouring particles to the inlet tube sheet, an effluent cooler may need to be taken out of service about every 1 to 3 months for foulant cleaning of the inlet tube sheet of the effluent cooler, including foulant cleaning of the inlet tube sheet and about six (6) inches into tubes of the effluent cooler.

[29] FIG. 3 illustrates an embodiment of metal shroud 48 comprising flute or ferrule 50. In an aspect, ferrule 50 has a unitary structure. In an aspect, the ferrule 50 comprises elongated body 54 having flared opening 52 at end 62, and outlet 64 at end 66. In an aspect the inside diameter of ferrule 50 may be feathered out from location 70 to end 66 to meet the outside diameter of ferrule 50 at end 66. In an aspect, the feathering may begin at location 70 in elongated body 54 about 0.25 inches from end 66. As shown in FIG. 3, elongated body 54 may comprise feathered portion 60 between location 70 and end 66. In an aspect, ferrule 50 may be about 15 cm to about 32 cm in length between end 62 and end 66, in another aspect, about 15 cm to about 25 cm in length, and in another aspect, about 18 cm to about 22 cm in length. In an aspect, flared opening 52 may have a radius of about 0.13 to about 0.19 inches as shown in FIG. 3. In a related aspect, the ferrules may extend into the tubes for a distance of about 15 cm to about 32 cm, in another aspect, about 15 cm to about 25 cm, and in another aspect, about 18 cm to about 22 cm.

[30] In one aspect, it has been found that it is easier to remove metal shrouds by removing the ferrules and inserting new ferrules than it is try to physically scour the inlet tube sheet and the inlets of the tubes and about 15 cm into the tubes.

[31] While a flared end is shown in FIG. 3, those skilled in the art will recognize that in accordance with aspects of the disclosure, ferrule 50 may have more of a "T" shape, in that opening 52 may comprise a 90 degree or closer to a 90 degree angle than the flared opening shown in FIG. 3.

[32] In an aspect, the thickness of wall 56 of non-feathered portion 58 of ferrule 50 may be about 0.065 inches. In an aspect, the outside diameter at flared end 62 may be about 1.5 inches, the inside diameter of non-feathered portion 58 may be about 1.102 inches, and the outside diameter of non-feathered portion 58 may be about 1.232 inches. Those skilled in the art will recognize that the ratio or relationship between various dimensions as disclosed herein, e.g., the ratio or relationship between the inside diameter of non-feathered portion 58 to the thickness of wall 56 of non-feathered portion 58 to the outside diameter of non- feathered portion 58 to the outside diameter at flared end 54 may be about 1.102 : 0.065 : 1.232 : 1.5.

[33] It has been found that by providing a flared opening of the flute or ferrule to receive the scouring particles, graduated conveying of the scouring particles may be provided, wherein more intense or greater scouring may be performed where fouling may be the greater, e.g., at proximal rim portion 68, than where fouling may be less, e.g., at location 70.

[34] Those of skill in the art will recognize that in accordance with the disclosure, metal shrouds comprising the inlet tube sheet may be provided instead of a metal shroud comprising a flute or ferrule to receive the scouring particles. In an aspect, an inner bore weld configuration may be used to provide a metal shroud comprising the inlet tube sheet. Those skilled in the art will recognize that a metal shroud comprising a ferrule configuration as shown in FIG. 2 and FIG. 3 may be preferred over an inner bore weld configuration wherein the metal shroud comprises the inlet tube sheet. For example, when the metal shroud comprising a ferrule configuration as shown in FIG. 2 and FIG. 3 is used, the inlet tube sheet is shielded to least some extent by the ferrules, whereas in the inner bore weld configuration, the metal shroud comprises the inlet tube sheet itself. In addition, ferrules can be more easily separated and removed from an inlet tube sheet and replaced with new ferrules, than separating the inlet tube sheet from tubes welded thereto by inner bore welds and then using inner bore welds to weld the tubes to a new inlet tube sheet.

[35] FIG. 4 illustrates a flow diagram of process 400 in accordance with aspects of the disclosure. Process 400 may be carried out or practiced by using the apparatus previously described with respect to FIG. 1, FIG. 2, and FIG. 3. In an aspect, step 401 may comprise recovering heat from reactor effluent, wherein the recovering comprises heat exchange between the reactor effluent and water in an effluent cooler. In an aspect the reactor effluent comprises acrylonitrile or methacrylonitrile from an ammoxidation reactor. In an aspect, step 402 comprises shielding metal of the effluent cooler with metal shrouds at inlets of heat exchanger tubes of the effluent cooler. In an aspect, step 403 comprises online cleaning of fouling from components of the reactor effluent that accumulate on the metal shroud. In an aspect, the online cleaning comprises conveying scouring particles to the metal shroud and through tubes of the effluent cooler. In an aspect, the metal shroud shields the inlets of the effluent cooler from erosion during the online cleaning that would otherwise occur at the inlets without the metal shroud.

[36] Process 400 may further comprise additional steps as previously described (but not shown in FIG. 4).

[37] While in the foregoing specification this disclosure has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the disclosure is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the disclosure. It should be understood that the features of the disclosure are susceptible to modification, alteration, changes or substitution without departing from the spirit and scope of the disclosure or from the scope of the claims. For example, the dimensions, number, size and shape of the various components may be altered to fit specific applications. Accordingly, the specific embodiments illustrated and described herein are for illustrative purposes only.

Claims

WE CLAIM:

1. A process comprising:

recovering heat from reactor effluent, the reactor effluent comprising acrylonitrile or methacrylonitrile from an ammoxidation reactor, wherein the recovering comprises heat exchange between the reactor effluent and coolant in an effluent cooler;

shielding metal of the effluent cooler with a metal shroud at inlets of heat exchanger tubes of the effluent cooler; and

online cleaning of fouling from components of the reactor effluent that accumulate on the metal shroud, wherein the online cleaning comprises conveying scouring particles to the metal shroud and through tubes of the effluent cooler.

2. The process of claim 1 , wherein the coolant is water.

3. The process of claim 2, wherein the water is boiler feed water.

4. The process of claim 1 , wherein the scouring particles comprises a scouring agent selected from the group consisting of ammonium sulfate, sand, and combinations thereof.

5. The process of claim 1, wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 3 to 11 days.

6. The process of claim 1, wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 5 to 9 days.

7. The process of claim 1 , wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 6 to 8 days.

8. The process of claim 1, wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 7 days.

9. The process of claim 1, wherein the scouring particles are conveyed to the inlet tube sheet of the effluent cooler at a velocity of about 0.5 meters/second to about 1 meter/second.

10. The process of claim 1, wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is for about three seconds to about thirty minutes.

11. The process of claim 1 , wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is for about three seconds to fifteen minutes.

12. The process of claim 1, wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is for greater than about 2 minutes to about 30 minutes.

13. The process of claim 1, wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is for greater than about 2 minutes to about 15 minutes.

14. The process of claim 1, wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is for greater than about 2 minutes to about 5 minutes.

15. The process of claim 1, wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is through a nozzle.

16. The process of claim 15, wherein the conveying of the scouring particles to the inlet tube sheet of the effluent cooler is through a full cone spray nozzle.

17. The process of claim 15, wherein the outlet of the nozzle is about 1 to 3 meters from the inlets of the tubes or the inlet tube sheet of the effluent cooler.

18. The process of claim 16, wherein the scouring particles is sprayed through the full cone spray nozzle with a spray angle of about 30 to 90 degrees.

19. The process of claim 18, wherein the scouring particles is sprayed through the full cone spray nozzle with a spray angle of about 70 degrees.

20. The process of claim 1, wherein the metal shroud comprises a ferrule, the ferrule comprising an elongated body comprising a flared opening at a first end, an outlet at a second end, and a wall between the first end and the second end.

21. The process of claim 20, wherein the metal shroud comprises a plurality of ferrules, wherein each ferrule corresponds to an inlet of a tube of the effluent cooler.

22. The process of claim 21, wherein each ferrule has a unitary structure.

23. The process of 20, wherein the wall comprises a feathered portion and a non-feathered portion, wherein the feathered portion is closer to the second end than the first end, and the non- feathered portion is closer to the first end than the second end.

24. The process of claim 23, wherein the feathered portion has an inside diameter that increases as the feathered portion extends from the non-feathered portion towards the second end.

25. The process of claim 20, wherein the flared opening has an inside diameter that decreases as it extends away from the first end and towards the second end.

26. The process of claim 25, wherein the conveying of scouring particles is at a greater pressure at the flared opening than in a portion of the ferrule downstream from the flared opening.

27. The process of claim 4, wherein the scouring agent has an average particle size of about 1 to about 5 mm.

28. The process of claim 4, wherein the ammonium sulfate is conveyed in an amount of about 0.025 to about 0.10 kg per square meter of a tube sheet of the effluent cooler.

29. The process of claim 4, wherein the process uses about 0.0002 to about 0.00075 kg of ammonium sulfate per metric ton of acrylonitrile produced.

30. A process comprising:

recovering heat from reactor effluent, the reactor effluent comprising acrylonitrile or methacrylonitrile from an ammoxidation reactor, wherein the recovering comprises heat exchange between the reactor effluent and coolant in an effluent cooler; and

online cleaning of fouling from components of the reactor effluent that accumulate on the effluent cooler, wherein the online cleaning comprises conveying scouring particles to the effluent cooler and through tubes of the effluent cooler,

wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler more than about every 3 to about 11 days.

31. The process of claim 30, wherein the coolant is water

32. The process of claim 31, wherein the water is boiler feed water.

33. The process of claim 30, wherein the scouring particles comprises a scouring agent selected from the group consisting of ammonium sulfate, sand, and combinations thereof.

34. The process of claim 30, wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 5 to about 9 days.

35. The process of claim 30, wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 6 to about 8 days.

36. The process of claim 30, wherein the online cleaning comprises conveying the scouring particles to an inlet tube sheet and through tubes of the effluent cooler about every 7 days.

37. The process of claim 30, wherein the scouring particles are conveyed to the inlet tube sheet of the effluent cooler at a velocity of about 0.5 meters/second to about 1 meter/second.

38. The process of claim 30, wherein the nozzle is a full cone spray nozzle.

39. The process of claim 38, the full cone spray nozzle has a spray angle of about 30 to 90 degrees.

40. The process of claim 39, wherein the full cone spray nozzle has a spray angle of about 70 degrees.

41. The process of claim 33, wherein the scouring agent has an average particle size of about 1 to about 5 mm.

42. The process of claim 30, wherein the ammonium sulfate is conveyed in an amount of about 0.025 to about 0.10 kg per square meter of a tube sheet of the effluent cooler.

43. The process of claim 30, wherein the process uses about 0.0002 to about 0.00075 kg of ammonium sulfate per metric ton of acrylonitrile produced.

44. An apparatus comprising:

an effluent cooler configured to recover heat from effluent from an ammoxidation reactor, the effluent cooler comprising an inlet tube sheet, a plurality of heat exchanger tubes, an a heat exchanger shell, wherein the plurality of heat exchanger tubes are configured to receive the reactor effluent at the inlet tube sheet, wherein the heat exchanger shell is configured to receive coolant;

a source of scouring particles;

a nozzle configured to receive the scouring particles from the source and spray the scouring particles toward the inlet tube sheet for online cleaning of fouling; and

a metal shroud at inlets of heat exchanger tubes of the effluent cooler.

45. The apparatus of claim 44, wherein the scouring particles comprises a scouring agent selected from the group consisting of ammonium sulfate, sand, and combinations thereof.

46. The apparatus of claim 44, wherein the nozzle is a full cone spray nozzle.

47. The apparatus of claim 46, wherein the scouring particles is sprayed through the full cone spray nozzle with a spray angle of about 30 to 90 degrees.

48. The apparatus of claim 47, wherein the scouring particles is sprayed through the full cone spray nozzle with a spray angle of about 70 degrees.

49. The apparatus of claim 44, wherein the metal shroud comprises a ferrule, the ferrule comprising an elongated body comprising a flared opening at a first end, an outlet at a second end, and a wall between the first end and the second end.

50. The apparatus of claim 49, wherein the metal shroud comprises a plurality of ferrules, wherein each ferrule corresponds to an inlet of a tube of the effluent cooler.

51. The apparatus of claim 50, wherein each ferrule has a unitary structure.

52. The apparatus of claim 44, wherein the outlet of the nozzle is about 1 to 3 meters from the inlets of the tubes or the inlet tube sheet of the effluent cooler.

53. The apparatus of claim 49, wherein the wall comprises a feathered portion and a non-feathered portion, wherein the feathered portion is closer to the second end than the first end, and the non-feathered portion is closer to the first end than the second end.

54. The apparatus of claim 53, wherein the feathered portion has an inside diameter that increases as the feathered portion extends from the non-feathered portion towards the second end.

55. The apparatus of claim 53, wherein the flared opening has an inside diameter that decreases as it extends away from the first end and towards the second end.

56. The apparatus of claim 51, wherein the ferrule extends into the tube for a distance of about 15 cm to about 32 cm.