WO2004103945A1 - A purification process of crude terephthalic acid in a post oxidation zone by the addition of steam - Google Patents

A purification process of crude terephthalic acid in a post oxidation zone by the addition of steam Download PDF

Info

Publication number
WO2004103945A1
WO2004103945A1 PCT/US2004/012076 US2004012076W WO2004103945A1 WO 2004103945 A1 WO2004103945 A1 WO 2004103945A1 US 2004012076 W US2004012076 W US 2004012076W WO 2004103945 A1 WO2004103945 A1 WO 2004103945A1
Authority
WO
WIPO (PCT)
Prior art keywords
post oxidation
product
zone
post
carboxylic acid
Prior art date
Application number
PCT/US2004/012076
Other languages
French (fr)
Other versions
WO2004103945A8 (en
Inventor
Robert Lin
Marcel De Vreede
Johannes Wilhelmus Sluijmers
Martin De Boer
Thomas Earl Woodruff
Original Assignee
Eastman Chemical Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Chemical Company filed Critical Eastman Chemical Company
Priority to BRPI0409500-6A priority Critical patent/BRPI0409500A/en
Priority to CA002522440A priority patent/CA2522440A1/en
Priority to JP2006532432A priority patent/JP2006528682A/en
Priority to EP04785490A priority patent/EP1620385A1/en
Priority to MXPA05011302A priority patent/MXPA05011302A/en
Publication of WO2004103945A1 publication Critical patent/WO2004103945A1/en
Publication of WO2004103945A8 publication Critical patent/WO2004103945A8/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
    • C07C51/46—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation by azeotropic distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C63/00—Compounds having carboxyl groups bound to a carbon atoms of six-membered aromatic rings
    • C07C63/14—Monocyclic dicarboxylic acids
    • C07C63/15—Monocyclic dicarboxylic acids all carboxyl groups bound to carbon atoms of the six-membered aromatic ring
    • C07C63/26—1,4 - Benzenedicarboxylic acid

Definitions

  • the present invention relates to a process for heating carboxylic acid slurry in a post oxidation zone by the addition of steam. More specifically, 10 the present invention relates to a process for heating a terephthalic acid slurry in a post oxidation zone by the addition of steam in a process for the production of a crystallized product.
  • Terephthalic acid is commercially produced by oxidation of paraxylene in the presence of a catalyst, such as, for example, Co, Mn, Br and a solvent.
  • a catalyst such as, for example, Co, Mn, Br and a solvent.
  • Terephthalic acid used in the production of polyester fibers, films, and resins must be further treated to remove impurities present due to 20 the initial oxidation of paraxylene.
  • Typical commercial processes remove impurities by isolating a crude terephthalic acid solid, dissolving the solid in water at high temperatures and pressures, hydrogenating the resultant solution, cooling and crystallizing the terephthalic acid product out of solution, and separating the solid terephthalic product from the liquid as discussed in U. S. Patent No. 3,584,039, herein incorporated by reference.
  • Colored impurities from the benzil, anthraquinone, and fluorenone families are hydrogenated to colorless products and leave the process with the terephthalic acid solid product and wastewater streams.
  • Still other methods of obtaining a terephthalic acid product suitable as starting material for the production of polyesters do not involve a hydrogenation step.
  • a method of producing a terephthalic acid product suitable for polyester production is to completely or nearly completely react paraxylene in a multiple stage oxidation process.
  • a unique and novel process is provided wherein a crude terephthaic slurry produced by the oxidation of an aromatic feedstock, typically p-xylene, is further oxidized in a multiple step process wherein heat is provided to a post oxidation zone by steam addition.
  • the addition of steam to an oxidation zone subsequent to the primary oxidation zone results in a higher quality terephthalic acid product compared to conventional techniques.
  • This invention provides a process to produce a crystallized product from a crude carboxylic acid slurry by injecting steam in a post oxidation zone subsequent to the primary oxidation zone.
  • a process to produce a post oxidation product comprising (a) oxidizing in a post oxidation zone a crude carboxylic acid slurry in the presence of steam to form the post oxidation product; wherein the post oxidation zone comprises at least one post oxidation device; wherein thecrude carboxylic acid slurry comprises at least one carboxylic acid;
  • a process to produce a crystallized product comprising the following... steps:
  • a process to produce a crystallized product comprises oxidizing in a post oxidation zone a crude carboxylic acid slurry in the presence of steam to form the post oxidation product; wherein the crude carboxylic acid slurry comprises terephthalic acid; wherein the post oxidation zone comprises at least one post oxidation device; wherein the post oxidation product has a b* color of less than about 4.5.
  • a process to produce a crystallized product comprises the following steps:
  • crystallizing in a crystallization zone the post oxidation product to form a crystallized product wherein the crystallization zone comprises at least one crystallizer; wherein the crystallizer is operated at a temperature between about 140°C and 190°C ; and wherein the crystallized product has a b* color of less than 4.5.
  • Figure 1 is a schematic of a process for heating a crude carboxylic acid slurry in a post oxidation zone by the addition of steam to produce a post oxidation product.
  • the present invention provides a process to produce a post oxidation product comprising oxidizing a crude carboxylic acid slurry in the presence of steam to form the post oxidation product 120 and a offgas stream 80.
  • a process to produce a post oxidation product 120 is provided.
  • the process comprises oxidizing in a post oxidation zone 90 a crude carboxylic acid slurry 30 in the presence of steam 100 to form the post oxidation product 120 and an offgas stream 80; wherein the post oxidation zone 90 comprises at least one post oxidation device; wherein the carboxylic acid slurry comprises at least one carboxylic acid; and wherein the post oxidation product 120 has a b* color of less than 4.5.
  • Step (a) comprises oxidizing the crude carboxylic acid slurry 30 in a post oxidation zone 90 in the presence of steam 100 to form a post oxidation product 120.
  • the crude carboxylic acid slurry 30 is produced by oxidizing in a primary oxidation zone 20 an aromatic feed stock 10.
  • the primary oxidation zone 20 comprises at least one oxidation reactor, and the crude carboxylic acid slurry 30 comprises at least one carboxylic acid.
  • the oxidizing in the primary oxidation zone 20 is completed under reaction conditions, which produces a crude carboxylic acid slurry 30 from an aromatic feedstock 10.
  • the crude carboxylic acid slurry 30 comprises at least one carboxylic acid.
  • the carboxylic acid is terephthalic acid.
  • the crude carboxylic acid slurry 30 would be referred to as crude terephthalic acid slurry.
  • suitable carboxylic acids include, but are not limited to, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and mixtures thereof.
  • Crude terephthalic acid slurry is conventionally synthesized via the liquid phase oxidation of paraxylene in the presence of metal oxidation catalyst.
  • Suitable catalysts include, but are not limited to, cobalt, manganese and bromide compounds, which are soluble in the selected solvent.
  • Suitable solvents include, but are not limited to, aliphatic mono-carboxylic acids, preferably containing 2 to 6 carbon atoms, or benzoic acid and mixtures thereof and mixtures of these compounds with water.
  • the solvent is acetic acid mixed with water in a ratio of about 5:1 to about 25:1, preferably between about 10:1 and about 15:1.
  • suitable solvents such as those disclosed herein, may also be utilized.
  • Patents disclosing the production of terephthalic acid, such as 4,158,738 and 3,996,271 are hereby incorporated by reference.
  • the primary oxidation zone 20 has a water concentration less than about 10 wt%, preferably the water concentration is less than about 8 wt%, and most;' preferably the water concentration is less than about 6 wt%.
  • the post oxidation zone 90 comprises at least one post oxidation device.
  • the crude carboxylic acid slurry 30 is fed to the post oxidation zone 90.
  • the post oxidation zone 90 comprises at least one post oxidation device.
  • post oxidation means that the oxidation occurs after the primary oxidation zone 20 discussed previously.
  • the post oxidation zone 90 can comprise post oxidation devices in series.
  • the crude carboxylic acid slurry 30 in the post oxidation device is heated with steam 100 to between about 180°C and about 280°C, preferably between about 190°C
  • the temperature is the internal temperature of the post oxidation device.
  • the temperature can vary within the specified range for each post oxidation device.
  • the steam 100 can be fed in the post oxidation zone 90 by any means known in the art. For example, a connection can be made for the steam 100 to be directly fed to the acetic acid vapor line. So the steam could be injected into the digester through the sparge ring.
  • the post oxidation zone 90 can be heated with acetic acid vapor.
  • Additional air or molecular oxygen may be fed to the post oxidation zone 90 in an amount necessary to oxidize a substantial portion of the partially oxidized products and 4-carboxybenzaldehyde (4-CBA) in the crude carboxylic acid slurry 30 to the corresponding carboxylic acid.
  • 4-CBA 4-carboxybenzaldehyde
  • at least 70% by weight of the 4-CBA is converted to terephthalic acid in the post oxidation zone 90.
  • Preferably at least 80% by weight of the 4-CBA is converted to terephthalic acid in the post oxidation zone 90.
  • 4- carboxybenzaldehyde and p-toluic acid in high enough concentrations in the terephthalic acid product can be particularly detrimental to polymerization processes as they act as a chain terminator during the condensation reaction between terephthalic acid and ethylene glycol in the production of PET and can be detrimental to the performance of terephthalic acid hydrogenation processes.
  • Typical terephthalic acid product contains on a weight basis less than 500 parts per million (ppm) 4- carboxybenzaldehyde and less than 250 ppm p-toluic acid.
  • the post oxidation zone is operated at a temperature and pressure sufficient that the b* color of the post oxidation product 120 ranges from about 0.5 to about 4.5.
  • Step (b) comprises purifying the post oxidation product before or after a crystallization zone to form a decolorized post oxidation product having b* color of less than 4.5.
  • the purifying of the post oxidation product can be accomplished by any means known in the art.
  • colored impurities from the benzil, anthroquinone, and fluorenone families can be hydrogenated to colorless products.
  • any amount of process steps can be between the post oxidation zone and the purifying of the post oxidation product and the isolation or recovery of the post oxidation product if desired.
  • the b* color of the post oxidation product in conduit 120 is between about 0.5 to about 4.5.
  • the b* color of the decolorized post oxidation product in conduit 120 is between 0.5 to 2.0.
  • the b* color in the decolorized post oxidation product in conduit 120 is between 0.5 to 1.5.
  • the b* color is one of the three-color attributes measured on a spectroscopic reflectance-based instrument. The color can be measured by any device known in the art. A Hunter Ultrascan XE instrument is typically the measuring device. Positive readings signify the degree of yellow (or absorbance of blue), while negative readings signify the degree of blue (or absorbance of yellow).
  • Step (c) comprises crystallizing the post oxidation product 120 in the crystallization zone 160 to form a crystallized product 180; wherein the crystallized product 180 has a b* color of less than 4.5.
  • the crystallization zone 160 comprises at least one crystallizer. Vapor product from the crystallization zone 160 is withdrawn via line 130, condensed in a condenser zone 170, which comprises at least one condenser and returned to the crystallization zone 160.
  • the liquid in conduit 140 or vapor 130 in the condenser zone 170 can be recycled, or it can be withdrawn or sent to an energy recovery device.
  • the liquid crystallization offgas 150 from the condenser zone 170 is removed via line 150 and can be routed to a recovery system where the solvent is removed and crystallization offgas 150 comprising VOCs and pollutants are burned.
  • the post oxidation product 120 from the post oxidation zone 90 is withdrawn via line 120 and fed to a crystallization zone 160 comprising at least one crystallizer where it is cooled to a temperature between about 110°C and about 190°C to form a
  • crystallized product 180 preferably to a temperature between about 140°C
  • the b* color of the crystallized product in conduit 180 is between about 0.5 to about 4.5. More preferably, the b* color of the crystallized product in conduit 180 is between 0.5 to 2.0. Most preferably, the b* color in the crystallized product in conduit 180 is between 0.5 to 1.5
  • the crystallized product 180 from the crystallization zone 160 is withdrawn via line 180. Typically, the crystallized product 180 is then fed directly to a vessel and cooled to form a cooled crystallized product.
  • the cooled crystallized product is cooled in a vessel to typically a temperature of approximately 90° C or less than before being introduced into a process for recovering the carboxylic acid as a dry powder or wet cake.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The present invention relates to a process for heating a secondary oxidizer with steam. More specifically, the present invention relates to a process for heating a secondary oxidizer with steam in a process for the production of a crystallized product. A process to produce a crystallized product comprises the following steps (a) oxidizing in an primary oxidation zone an aromatic feedstock to produce a crude carboxylic acid slurry; (b) oxidizing said crude carboxylic acid slurry in a post oxidation zone in the presence of steam to form a post oxidation product; (c) purifying said post oxidation product to a decolorized post oxidation product; and (d) crystallizing in a crystallization zone said post oxidation product to form a crystallized product.

Description

A PURIFICATION PROCESS OF CRUDE TEREPHTHALIC ACID IN A POST OXIDATION ZONE BY THE ADDITION OF STEAM
5 FIELD OF INVENTION
The present invention relates to a process for heating carboxylic acid slurry in a post oxidation zone by the addition of steam. More specifically, 10 the present invention relates to a process for heating a terephthalic acid slurry in a post oxidation zone by the addition of steam in a process for the production of a crystallized product.
BACKGROUND OF THE INVENTION
15
Terephthalic acid (TPA) is commercially produced by oxidation of paraxylene in the presence of a catalyst, such as, for example, Co, Mn, Br and a solvent. Terephthalic acid used in the production of polyester fibers, films, and resins must be further treated to remove impurities present due to 20 the initial oxidation of paraxylene. Typical commercial processes remove impurities by isolating a crude terephthalic acid solid, dissolving the solid in water at high temperatures and pressures, hydrogenating the resultant solution, cooling and crystallizing the terephthalic acid product out of solution, and separating the solid terephthalic product from the liquid as discussed in U. S. Patent No. 3,584,039, herein incorporated by reference. Colored impurities from the benzil, anthraquinone, and fluorenone families are hydrogenated to colorless products and leave the process with the terephthalic acid solid product and wastewater streams. Still other methods of obtaining a terephthalic acid product suitable as starting material for the production of polyesters do not involve a hydrogenation step. A method of producing a terephthalic acid product suitable for polyester production is to completely or nearly completely react paraxylene in a multiple stage oxidation process. In this invention, a unique and novel process is provided wherein a crude terephthaic slurry produced by the oxidation of an aromatic feedstock, typically p-xylene, is further oxidized in a multiple step process wherein heat is provided to a post oxidation zone by steam addition. The addition of steam to an oxidation zone subsequent to the primary oxidation zone results in a higher quality terephthalic acid product compared to conventional techniques.
SUMMARY OF THE INVENTION
This invention provides a process to produce a crystallized product from a crude carboxylic acid slurry by injecting steam in a post oxidation zone subsequent to the primary oxidation zone.
In a first embodiment of this invention, a process to produce a post oxidation product is provided comprising (a) oxidizing in a post oxidation zone a crude carboxylic acid slurry in the presence of steam to form the post oxidation product; wherein the post oxidation zone comprises at least one post oxidation device; wherein thecrude carboxylic acid slurry comprises at least one carboxylic acid;
(b) purifying the post oxidation product to form a decolorized post oxidation product having b* color of less than 4.5.
In another embodiment of this invention, a process to produce a crystallized product is provided. The process comprising the following... steps:
(a) oxidizing in a post oxidation zone thecrude carboxylic acid slurry in a post oxidation zone in the presence of steam to form a post oxidation product and an offgas stream; wherein the post oxidation zone comprises at least one post oxidation device; (b) purifying the post oxidation product before or after the crystallization zone to form a decolorized post oxidation product having b* color of less than 4.5; and
(c) crystallizing in a crystallization zone the post oxidation product; wherein the crystallization zone comprises at least one crystallizer. In another embodiment of this invention, a process to produce a crystallized product is provided. The process comprises oxidizing in a post oxidation zone a crude carboxylic acid slurry in the presence of steam to form the post oxidation product; wherein the crude carboxylic acid slurry comprises terephthalic acid; wherein the post oxidation zone comprises at least one post oxidation device; wherein the post oxidation product has a b* color of less than about 4.5.
In another embodiment of this invention, a process to produce a crystallized product is provided. The process comprises the following steps:
(a) oxidizing the crude carboxylic acid slurry in a post oxidation zone in the presence of steam to form a post oxidation product; wherein the post oxidation zone comprises at least one post oxidation device; wherein the pressure of the post oxidation zone is between about 10 barg to about 50 barg; and
(b) crystallizing in a crystallization zone the post oxidation product to form a crystallized product; wherein the crystallization zone comprises at least one crystallizer; wherein the crystallizer is operated at a temperature between about 140°C and 190°C ; and wherein the crystallized product has a b* color of less than 4.5.
These objects, and other objects, will become more apparent to others with ordinary skill in the art after reading this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic of a process for heating a crude carboxylic acid slurry in a post oxidation zone by the addition of steam to produce a post oxidation product.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a process to produce a post oxidation product comprising oxidizing a crude carboxylic acid slurry in the presence of steam to form the post oxidation product 120 and a offgas stream 80. In a first embodiment of this invention, a process to produce a post oxidation product 120 is provided. The process comprises oxidizing in a post oxidation zone 90 a crude carboxylic acid slurry 30 in the presence of steam 100 to form the post oxidation product 120 and an offgas stream 80; wherein the post oxidation zone 90 comprises at least one post oxidation device; wherein the carboxylic acid slurry comprises at least one carboxylic acid; and wherein the post oxidation product 120 has a b* color of less than 4.5.
This oxidizing step and the post oxidation zone are described subsequently in this disclosure. In another embodiment of the invention, a process to produce a crystallized product 180 is provided as shown in Figure 1. The process comprises the following steps. Step (a) comprises oxidizing the crude carboxylic acid slurry 30 in a post oxidation zone 90 in the presence of steam 100 to form a post oxidation product 120. Generally, the crude carboxylic acid slurry 30 is produced by oxidizing in a primary oxidation zone 20 an aromatic feed stock 10. The primary oxidation zone 20 comprises at least one oxidation reactor, and the crude carboxylic acid slurry 30 comprises at least one carboxylic acid.
The oxidizing in the primary oxidation zone 20 is completed under reaction conditions, which produces a crude carboxylic acid slurry 30 from an aromatic feedstock 10. Typically, the crude carboxylic acid slurry 30 comprises at least one carboxylic acid. Generally, the carboxylic acid is terephthalic acid.
Therefore, when terephthalic acid is utilized, the crude carboxylic acid slurry 30 would be referred to as crude terephthalic acid slurry. However, suitable carboxylic acids include, but are not limited to, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and mixtures thereof. Crude terephthalic acid slurry is conventionally synthesized via the liquid phase oxidation of paraxylene in the presence of metal oxidation catalyst. Suitable catalysts include, but are not limited to, cobalt, manganese and bromide compounds, which are soluble in the selected solvent. Suitable solvents include, but are not limited to, aliphatic mono-carboxylic acids, preferably containing 2 to 6 carbon atoms, or benzoic acid and mixtures thereof and mixtures of these compounds with water. Preferably, the solvent is acetic acid mixed with water in a ratio of about 5:1 to about 25:1, preferably between about 10:1 and about 15:1. However, it should be appreciated that other suitable solvents, such as those disclosed herein, may also be utilized. Patents disclosing the production of terephthalic acid, such as 4,158,738 and 3,996,271 , are hereby incorporated by reference.
In cases where the carboxylic acid is terephthalic acid, the primary oxidation zone 20 has a water concentration less than about 10 wt%, preferably the water concentration is less than about 8 wt%, and most;' preferably the water concentration is less than about 6 wt%.
The post oxidation zone 90 comprises at least one post oxidation device. The crude carboxylic acid slurry 30 is fed to the post oxidation zone 90. The post oxidation zone 90 comprises at least one post oxidation device. The term post oxidation means that the oxidation occurs after the primary oxidation zone 20 discussed previously. For example, the post oxidation zone 90 can comprise post oxidation devices in series.
When the carboxylic acid is terephthalic acid, the crude carboxylic acid slurry 30 in the post oxidation device is heated with steam 100 to between about 180°C and about 280°C, preferably between about 190°C
and about 240°C, and most preferably between 195 °C to 215°C and further oxidized with air or a source of molecular oxygen fed by line 115 to produce a post oxidation product 120. The temperature is the internal temperature of the post oxidation device. When the post oxidation zone comprises more than one post oxidation device, the temperature can vary within the specified range for each post oxidation device. The steam 100 can be fed in the post oxidation zone 90 by any means known in the art. For example, a connection can be made for the steam 100 to be directly fed to the acetic acid vapor line. So the steam could be injected into the digester through the sparge ring. In addition to using steam, the post oxidation zone 90 can be heated with acetic acid vapor.
Additional air or molecular oxygen may be fed to the post oxidation zone 90 in an amount necessary to oxidize a substantial portion of the partially oxidized products and 4-carboxybenzaldehyde (4-CBA) in the crude carboxylic acid slurry 30 to the corresponding carboxylic acid. Generally, at least 70% by weight of the 4-CBA is converted to terephthalic acid in the post oxidation zone 90. Preferably at least 80% by weight of the 4-CBA is converted to terephthalic acid in the post oxidation zone 90. 4- carboxybenzaldehyde and p-toluic acid in high enough concentrations in the terephthalic acid product can be particularly detrimental to polymerization processes as they act as a chain terminator during the condensation reaction between terephthalic acid and ethylene glycol in the production of PET and can be detrimental to the performance of terephthalic acid hydrogenation processes. Typical terephthalic acid product contains on a weight basis less than 500 parts per million (ppm) 4- carboxybenzaldehyde and less than 250 ppm p-toluic acid. Preferably, the post oxidation zone is operated at a temperature and pressure sufficient that the b* color of the post oxidation product 120 ranges from about 0.5 to about 4.5.
Step (b) comprises purifying the post oxidation product before or after a crystallization zone to form a decolorized post oxidation product having b* color of less than 4.5.
The purifying of the post oxidation product can be accomplished by any means known in the art. For example colored impurities from the benzil, anthroquinone, and fluorenone families can be hydrogenated to colorless products. In addition any amount of process steps can be between the post oxidation zone and the purifying of the post oxidation product and the isolation or recovery of the post oxidation product if desired.
The b* color of the post oxidation product in conduit 120 is between about 0.5 to about 4.5. Preferably, the b* color of the decolorized post oxidation product in conduit 120 is between 0.5 to 2.0. Most preferably, the b* color in the decolorized post oxidation product in conduit 120 is between 0.5 to 1.5. The b* color is one of the three-color attributes measured on a spectroscopic reflectance-based instrument. The color can be measured by any device known in the art. A Hunter Ultrascan XE instrument is typically the measuring device. Positive readings signify the degree of yellow (or absorbance of blue), while negative readings signify the degree of blue (or absorbance of yellow). Offgas from the post oxidation zone is withdrawn via line 80 and fed to a recovery system where the solvent is removed from the offgas. The solvent comprising volatile organic compounds (VOCs). The VOCs and any hazardous pollutants may be incinerated. Step (c) comprises crystallizing the post oxidation product 120 in the crystallization zone 160 to form a crystallized product 180; wherein the crystallized product 180 has a b* color of less than 4.5.
Generally, the crystallization zone 160 comprises at least one crystallizer. Vapor product from the crystallization zone 160 is withdrawn via line 130, condensed in a condenser zone 170, which comprises at least one condenser and returned to the crystallization zone 160. Optionally, the liquid in conduit 140 or vapor 130 in the condenser zone 170 can be recycled, or it can be withdrawn or sent to an energy recovery device. In addition, the liquid crystallization offgas 150 from the condenser zone 170 is removed via line 150 and can be routed to a recovery system where the solvent is removed and crystallization offgas 150 comprising VOCs and pollutants are burned.
When the carboxylic acid is terephthalic acid, the post oxidation product 120 from the post oxidation zone 90 is withdrawn via line 120 and fed to a crystallization zone 160 comprising at least one crystallizer where it is cooled to a temperature between about 110°C and about 190°C to form a
crystallized product 180, preferably to a temperature between about 140°C
to about 180°C, most preferably 150°C to170°C. Preferably, the b* color of the crystallized product in conduit 180 is between about 0.5 to about 4.5. More preferably, the b* color of the crystallized product in conduit 180 is between 0.5 to 2.0. Most preferably, the b* color in the crystallized product in conduit 180 is between 0.5 to 1.5 The crystallized product 180 from the crystallization zone 160 is withdrawn via line 180. Typically, the crystallized product 180 is then fed directly to a vessel and cooled to form a cooled crystallized product. When the carboxylic acid is terephthalic acid, the cooled crystallized product is cooled in a vessel to typically a temperature of approximately 90° C or less than before being introduced into a process for recovering the carboxylic acid as a dry powder or wet cake.
EXAMPLES
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Example 1
In a plant trial, steam was used in the heating of a post oxidation device. The temperature of the post oxidation device was operating at about 195°C to about 215°C. The airflow was set at a ratio of about 3.8 kg air/ton crude carboxylic acid slurry. The steam flow to the post oxidation device was between about 6.5 to about 8.2 metric tons/hour. An overall reduction in energy of 0.3 GJ/ton for producing terephthalic acid was observed. This represents a 5% reduction in energy versus operating without the use of steam to the post oxidation device. The acid burn and decomposition in the post oxidation device decreased due to the injection of steam into the post oxidation device. The acid loss (acetic acid/ton post oxidation product) dropped about 10%. Therefore, both reduction in energy consumption and acid burn were observed through the use of steam to heat the post oxidation device.

Claims

WE CLAIM:
1. A process to produce a post oxidation product comprising the following steps:
(a) oxidizing in a post oxidation zone a crude carboxylic acid slurry in the presence of steam to form said post oxidation product; wherein said post oxidation zone comprises at least one post oxidation device; wherein said crude carboxylic acid slurry comprises at least one carboxylic acid;
(b) purifying said post oxidation product to form a decolorized post oxidation product having b* color of less than 4.5.
2. A process according to claim 1 where said decolorized post oxidation product has a b* color less than 3.5.
3. A process according to claim 1 wherein said carboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and mixtures thereof.
4. A process according to claim 1 wherein said carboxylic acid is terephthalic acid.
5. A process according to claim 4 wherein said steam is used to heat said post oxidation zone to a temperature in a range from about 180°C to
about 280 °C.
6. A process according to claim 5 wherein said post oxidation zone is operated at a pressure of about 10 barg to about 50 barg.
7. A process to produce a crystallized product said process comprising the following steps: (a) oxidizing in a post oxidation zone said crude carboxylic acid slurry in a post oxidation zone in the presence of steam to form a post oxidation product and an offgas stream; wherein said post oxidation zone comprises at least one post oxidation device;
(b) purifying said post oxidation product before or after a crystallization zone to form a decolorized post oxidation product having b* color of less than 4.5; and
(c) crystallizing in said crystallization zone said post oxidation product ; wherein said crystallization zone comprises at least one crystallizer.
8. A process according to claim 7 wherein said purified post oxidation product has a b* color of less than 3.
9. A process according claim 7 wherein said carboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and mixtures thereof.
10. A process according to claim 7 wherein said carboxylic acid is terephthalic acid.
11. A process according to claim 10 wherein said steam is used to heat the post oxidation zone to a temperature in a range from about 180°C to
about 280°C.
12. A process according to claim 11 wherein said post oxidation zone is operated at a pressure of about 10 barg to about 50 barg.
13. The process according to claim 10 wherein said crystallizer is operated at a temperature between about 140°C and 190°C .
14. A process to produce a post oxidation product comprising oxidizing in a post oxidation zone a crude carboxylic acid slurry in the presence of steam to form said post oxidation product; wherein said crude carboxylic acid slurry comprises terephthalic acid; wherein said post oxidation zone comprises at least one post oxidation device; wherein said post oxidation product has a b* color of less than about 4.5.
15. A process according to claim 14 wherein said steam is used to heat the post oxidation zone to a temperature in a range from about 180°C to
about 280°C.
16 A process according to claim 15 wherein said post oxidation zone is operated at a pressure of about 10 barg to about 50 barg. 17. A process to produce crystallized product said process comprising the following steps:
(a) oxidizing said crude carboxylic acid slurry in a post oxidation zone in the presence of steam to form a post oxidation product; wherein said post oxidation zone comprises at least one post oxidation device; wherein the pressure of said post oxidation zone is between about 10 barg to about 50 barg; and
(b) crystallizing in a crystallization zone said post oxidation product to form a crystallized product; wherein said crystallization zone comprises at least one crystallizer; wherein said crystallizer is operated at a temperature between about 140°C and 190°C ; and wherein said crystallized product has a b* color of less than 4.5. 18. A process according to claim 17 where said crystallized product has a b* color of less than 3.
PCT/US2004/012076 2003-04-25 2004-04-19 A purification process of crude terephthalic acid in a post oxidation zone by the addition of steam WO2004103945A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BRPI0409500-6A BRPI0409500A (en) 2003-04-25 2004-04-19 processes for producing a post oxidation product and a crystallized product
CA002522440A CA2522440A1 (en) 2003-04-25 2004-04-19 A purification process of crude terephthalic acid in a post oxidation zone by the addition of steam
JP2006532432A JP2006528682A (en) 2003-04-25 2004-04-19 Method for heating crude carboxylic acid slurry in post-oxidation zone by adding steam
EP04785490A EP1620385A1 (en) 2003-04-25 2004-04-19 A purification process of crude terephtalic acid in a post oxidation zone by the addition of steam
MXPA05011302A MXPA05011302A (en) 2003-04-25 2004-04-19 A purification process of crude terephthalic acid in a post oxidation zone by the addition of steam.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/423,389 2003-04-25
US10/423,389 US20040215036A1 (en) 2003-04-25 2003-04-25 Method for heating a crude carboxylic acid slurry in a post oxidation zone by the addition of steam

Publications (2)

Publication Number Publication Date
WO2004103945A1 true WO2004103945A1 (en) 2004-12-02
WO2004103945A8 WO2004103945A8 (en) 2005-05-12

Family

ID=33299111

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2004/012076 WO2004103945A1 (en) 2003-04-25 2004-04-19 A purification process of crude terephthalic acid in a post oxidation zone by the addition of steam

Country Status (11)

Country Link
US (2) US20040215036A1 (en)
EP (1) EP1620385A1 (en)
JP (1) JP2006528682A (en)
KR (1) KR20060006938A (en)
CN (1) CN1780806A (en)
AR (1) AR043893A1 (en)
BR (1) BRPI0409500A (en)
CA (1) CA2522440A1 (en)
MX (1) MXPA05011302A (en)
RU (1) RU2005136662A (en)
WO (1) WO2004103945A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006028773A2 (en) * 2004-09-02 2006-03-16 Eastman Chemical Company Optimized purification production of terephthalic acid

Families Citing this family (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10206168A1 (en) * 2002-02-14 2003-08-21 Guehring Joerg Coupling for modular tool holder arms
AU2003293251A1 (en) * 2002-12-09 2004-06-30 Eastman Chemical Company Process for the oxidative purification of terephthalic acid
US7546747B2 (en) * 2004-01-15 2009-06-16 Eastman Chemical Company Process for production of a dried carboxylic acid cake suitable for use in polyester production
US20050283022A1 (en) * 2004-06-18 2005-12-22 Sheppard Ronald B Filtrate preparation process for terephthalic acid filtrate treatment
US7692036B2 (en) 2004-11-29 2010-04-06 Eastman Chemical Company Optimized liquid-phase oxidation
US7582793B2 (en) * 2004-09-02 2009-09-01 Eastman Chemical Company Optimized liquid-phase oxidation
US7692037B2 (en) 2004-09-02 2010-04-06 Eastman Chemical Company Optimized liquid-phase oxidation
US7683210B2 (en) 2004-09-02 2010-03-23 Eastman Chemical Company Optimized liquid-phase oxidation
US7507857B2 (en) 2004-09-02 2009-03-24 Eastman Chemical Company Optimized liquid-phase oxidation
US7910769B2 (en) 2004-09-02 2011-03-22 Eastman Chemical Company Optimized liquid-phase oxidation
US7504535B2 (en) 2004-09-02 2009-03-17 Eastman Chemical Company Optimized liquid-phase oxidation
US7589231B2 (en) 2004-09-02 2009-09-15 Eastman Chemical Company Optimized liquid-phase oxidation
US7381836B2 (en) 2004-09-02 2008-06-03 Eastman Chemical Company Optimized liquid-phase oxidation
US7568361B2 (en) 2004-09-02 2009-08-04 Eastman Chemical Company Optimized liquid-phase oxidation
US7563926B2 (en) * 2004-09-02 2009-07-21 Eastman Chemical Company Optimized liquid-phase oxidation
US7572936B2 (en) 2004-09-02 2009-08-11 Eastman Chemical Company Optimized liquid-phase oxidation
US7741515B2 (en) 2004-09-02 2010-06-22 Eastman Chemical Company Optimized liquid-phase oxidation
US7884232B2 (en) 2005-06-16 2011-02-08 Eastman Chemical Company Optimized liquid-phase oxidation
US20070155987A1 (en) * 2006-01-04 2007-07-05 O'meadhra Ruairi S Oxidative digestion with optimized agitation
US20070179312A1 (en) * 2006-02-02 2007-08-02 O'meadhra Ruairi Seosamh Process for the purification of a crude carboxylic axid slurry
US7501537B2 (en) * 2006-03-01 2009-03-10 Eastman Chemical Company Polycarboxylic acid production system employing oxidative digestion with reduced or eliminated upstream liquor exchange
US7816556B2 (en) * 2006-03-01 2010-10-19 Eastman Chemical Company Polycarboxylic acid production system employing enhanced multistage oxidative digestion
US7393973B2 (en) * 2006-03-01 2008-07-01 Eastman Chemical Company Polycarboxylic acid production system with enhanced residence time distribution for oxidative digestion
US7420082B2 (en) * 2006-03-01 2008-09-02 Eastman Chemical Company Polycarboxylic acid production system employing hot liquor removal downstream of oxidative digestion
US20070208194A1 (en) 2006-03-01 2007-09-06 Woodruff Thomas E Oxidation system with sidedraw secondary reactor
US7326807B2 (en) * 2006-03-01 2008-02-05 Eastman Chemical Company Polycarboxylic acid production system with enhanced heating for oxidative digestion
US7772424B2 (en) * 2006-03-01 2010-08-10 Eastman Chemical Company Polycarboxylic acid production system employing enhanced evaporative concentration downstream of oxidative digestion
US7326808B2 (en) * 2006-03-01 2008-02-05 Eastman Chemical Company Polycarboxylic acid production system employing cooled mother liquor from oxidative digestion as feed to impurity purge system
US8809556B2 (en) * 2012-07-20 2014-08-19 Eastman Chemical Company Oxidation process to produce a purified carboxylic acid product via solvent displacement and post oxidation

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3529021A (en) * 1966-03-17 1970-09-15 Mobil Oil Corp Terephthalic acid purification process
US4158738A (en) * 1977-05-26 1979-06-19 E. I. Du Pont De Nemours And Company Process for the production of fiber-grade terephthalic acid
SU1171452A1 (en) * 1983-05-10 1985-08-07 Всесоюзный Научно-Исследовательский И Проектный Институт Мономеров Method of producing tere- or iso-phthalic acids

Family Cites Families (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3064044A (en) * 1957-08-15 1962-11-13 Standard Oil Co Multistage oxidation system for preparing dicarboxylic acid
NL276649A (en) * 1960-10-12
GB983677A (en) * 1962-04-27 1965-02-17 Mitsui Petrochemical Ind A process for the preparation of terephthalic acid having extremely high purity
NL147412B (en) * 1964-12-15 1975-10-15 Mobil Oil Corp METHOD FOR PURIFYING TEREPHALIC ACID BY SUBLIMATION.
GB1152575A (en) 1965-05-17 1969-05-21 Standard Oil Co Purification of Aromatic Polycarboxylic Acids.
NL6606774A (en) * 1965-05-17 1966-11-18
US3584039A (en) * 1967-08-30 1971-06-08 Standard Oil Co Fiber-grade terephthalic acid by catalytic hydrogen treatment of dissolved impure terephthalic acid
GB1358520A (en) 1972-06-05 1974-07-03 Crampton K J A Oxidation of aromatic organic compounds
JPS5328421B2 (en) * 1973-05-15 1978-08-15
US3931305A (en) * 1973-08-20 1976-01-06 Standard Oil Company Terephthalic acid recovery by continuous flash crystallization
US3850983A (en) * 1973-10-15 1974-11-26 Standard Oil Co Separation of terephthalic from paratoluic acid from solutions thereof in water and/or acetic acid
JPS5614101B2 (en) 1974-07-31 1981-04-02
US4500319A (en) * 1979-02-26 1985-02-19 Congoleum Corporation Textured pile fabrics
IT1129759B (en) * 1980-01-23 1986-06-11 Montedison Spa METHOD TO RECOVER IN ACTIVE FORM THE COMPONENTS OF THE CATALYTIC SYSTEM OF THE SYNTHESIS OF TEREPHTHALIC ACID
JPS59104345A (en) 1982-12-03 1984-06-16 Kuraray Yuka Kk Production of terephthalic acid suitable for direct polymerization
JPS59106435A (en) * 1982-12-10 1984-06-20 Mitsubishi Chem Ind Ltd Production of high-purity terephthalic acid
US4500732A (en) * 1983-09-15 1985-02-19 Standard Oil Company (Indiana) Process for removal and recycle of p-toluic acid from terephthalic acid crystallizer solvent
US4892970A (en) * 1985-12-30 1990-01-09 Amoco Corporation Staged aromatics oxidation in aqueous systems
US4939297A (en) * 1989-06-05 1990-07-03 Eastman Kodak Company Extraction process for removal of impurities from terephthalic acid filtrate
US5095146A (en) * 1991-03-25 1992-03-10 Amoco Corporation Water addition to crystallization train to purify terephthalic acid product
US5175355A (en) * 1991-04-12 1992-12-29 Amoco Corporation Improved process for recovery of purified terephthalic acid
GB9310070D0 (en) * 1992-05-29 1993-06-30 Ici Plc Process for the production of purified terephthalic acid
US5567842A (en) * 1994-11-16 1996-10-22 Mitsubishi Chemical Corporation Process for producing terephthalic acid
US5510521A (en) * 1995-03-27 1996-04-23 Eastman Chemical Company Process for the production of aromatic carboxylic acids
US5756833A (en) * 1996-02-01 1998-05-26 Amoco Corporation Catalytic purification and recovery of dicarboxylic aromatic acids
CA2315151A1 (en) 1997-12-15 1999-06-24 Shell Internationale Research Maatschappij B.V. Method to produce aromatic carboxylic acids
US6297348B1 (en) * 1999-08-30 2001-10-02 Shell Oil Company Closely linking a NDA process with a pen process
JP2001288139A (en) 2000-02-04 2001-10-16 Mitsubishi Chemicals Corp Method for producing high-purity terephthalic acid
US7485747B2 (en) * 2001-06-04 2009-02-03 Eastman Chemical Company Two stage oxidation process for the production of aromatic dicarboxylic acids
US7196215B2 (en) * 2001-06-04 2007-03-27 Eastman Chemical Company Process for the production of purified terephthalic acid
US6689903B2 (en) * 2001-06-04 2004-02-10 Eastman Chemical Company Crystallization method for production of purified aromatic dicarboxylic acids
US7161027B2 (en) * 2002-12-09 2007-01-09 Eastman Chemical Company Process for the oxidative purification of terephthalic acid

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3529021A (en) * 1966-03-17 1970-09-15 Mobil Oil Corp Terephthalic acid purification process
US4158738A (en) * 1977-05-26 1979-06-19 E. I. Du Pont De Nemours And Company Process for the production of fiber-grade terephthalic acid
SU1171452A1 (en) * 1983-05-10 1985-08-07 Всесоюзный Научно-Исследовательский И Проектный Институт Мономеров Method of producing tere- or iso-phthalic acids

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 104, no. 9, 3 March 1986, Columbus, Ohio, US; abstract no. 68602u, V.F.NAZIMOK ET AL.: "Tere- or isophthalic acids" XP002299202 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006028773A2 (en) * 2004-09-02 2006-03-16 Eastman Chemical Company Optimized purification production of terephthalic acid
WO2006028773A3 (en) * 2004-09-02 2006-07-13 Eastman Chem Co Optimized purification production of terephthalic acid
US7615663B2 (en) 2004-09-02 2009-11-10 Eastman Chemical Company Optimized production of aromatic dicarboxylic acids

Also Published As

Publication number Publication date
WO2004103945A8 (en) 2005-05-12
CN1780806A (en) 2006-05-31
JP2006528682A (en) 2006-12-21
KR20060006938A (en) 2006-01-20
EP1620385A1 (en) 2006-02-01
BRPI0409500A (en) 2006-04-18
AR043893A1 (en) 2005-08-17
CA2522440A1 (en) 2004-12-02
US20060084824A1 (en) 2006-04-20
US7342128B2 (en) 2008-03-11
RU2005136662A (en) 2006-03-27
MXPA05011302A (en) 2006-01-24
US20040215036A1 (en) 2004-10-28

Similar Documents

Publication Publication Date Title
US20040215036A1 (en) Method for heating a crude carboxylic acid slurry in a post oxidation zone by the addition of steam
US7132566B2 (en) Process for the purification of a crude carboxylic acid slurry
KR101004211B1 (en) Process for the purification of crude carboxylic acid slurry
CA2448071C (en) Two stage oxidation process for the production of aromatic dicarboxylic acids
US7074954B2 (en) Process for the oxidative purification of terephthalic acid
US6562997B2 (en) Production of high purity aromatic carboxylic acid by oxidation in benzoic acid and water solvent
US7161027B2 (en) Process for the oxidative purification of terephthalic acid
US20070179312A1 (en) Process for the purification of a crude carboxylic axid slurry
US7358392B2 (en) Process for the oxidative purification of terephthalic acid
US7276625B2 (en) Process for production of a carboxylic acid/diol mixture suitable for use in polyester production
RU2254324C2 (en) Continuous method for preparing highly pure terephthalic acid
EP1569887A1 (en) Process for the purification of a crude carboxylic acid slurry

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): BW GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

CFP Corrected version of a pamphlet front page

Free format text: FIGURE ADDED

121 Ep: the epo has been informed by wipo that ep was designated in this application
CFP Corrected version of a pamphlet front page
CR1 Correction of entry in section i

Free format text: IN PCT GAZETTE 49/2004 UNDER (72) REPLACE "DE BOER, MARTI" BY "DE BOER, MARTIN"

CFP Corrected version of a pamphlet front page

Free format text: UNDER (54) PUBLISHED TITLE REPLACED BY CORRECT TITLE

WWE Wipo information: entry into national phase

Ref document number: 4130/DELNP/2005

Country of ref document: IN

WWE Wipo information: entry into national phase

Ref document number: 2522440

Country of ref document: CA

WWE Wipo information: entry into national phase

Ref document number: 2004785490

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: PA/a/2005/011302

Country of ref document: MX

WWE Wipo information: entry into national phase

Ref document number: 2006532432

Country of ref document: JP

Ref document number: 1020057020195

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 20048111371

Country of ref document: CN

WWE Wipo information: entry into national phase

Ref document number: 2005136662

Country of ref document: RU

WWP Wipo information: published in national office

Ref document number: 1020057020195

Country of ref document: KR

WWP Wipo information: published in national office

Ref document number: 2004785490

Country of ref document: EP

ENP Entry into the national phase

Ref document number: PI0409500

Country of ref document: BR

WWW Wipo information: withdrawn in national office

Ref document number: 2004785490

Country of ref document: EP