CN104496787B - Method for recovering waste acid mother liquid during acetic acid synthesis with methanol carbonylation method - Google Patents
Method for recovering waste acid mother liquid during acetic acid synthesis with methanol carbonylation method Download PDFInfo
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- CN104496787B CN104496787B CN201410854581.5A CN201410854581A CN104496787B CN 104496787 B CN104496787 B CN 104496787B CN 201410854581 A CN201410854581 A CN 201410854581A CN 104496787 B CN104496787 B CN 104496787B
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/26—Fractionating columns in which vapour and liquid flow past each other, or in which the fluid is sprayed into the vapour, or in which a two-phase mixture is passed in one direction
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract
The invention discloses a process for recovering waste acid mother liquid during acetic acid synthesis with a methanol carbonylation method. The process comprises the steps of separating acetic acid/ propionic acid, refining acetic acid, and refining propionic acid; extracting not less than 99.5% of acetic acid and not less than 99.7% of propionic acid, wherein a device for separating acetic acid/propionic acid is a thermal coupling jet coflow tower. With the adoption of the method, the effect recovery of acetic acid and propionic acid in the waste acid mother liquid can be achieved; meanwhile, the volume of waste liquid drained into an environmental protection section is reduced, and acidic impurity content is extremely low, and therefore, the treatment difficulty of the subsequent environmental protection section is reduced, and the pressure on environmental protection is reduced; the thermal coupling jet coflow tower is used, so that the energy consumption in recovery and the production cost can be decreased, and the method is more suitable for industrial popularization.
Description
Technical field
The present invention relates to a kind of application thermal coupling sprays the Finestill energy-saving technique of cocurrent tower and in particular to a kind of methanol carbonyl
The spent acid mother liquid recovery process of change method synthesis of acetic acid.
Background technology
Methanol carbonylation is a kind of industrial widely used acetic acid production.This production method is with methyl alcohol and an oxygen
Change carbon is raw material, catalyst reaction system coexists using single rhodium, single iridium or rhodium iridium, with halogen compounds such as methyl iodide or hydrogen iodides
As co-catalyst.Formic acid, a small amount of co-catalyst, acetic acid second is typically contained in the thick acetic acid that methanol carbonylation method is produced
The impurity such as other organic and inorganic salts such as ester, propionic acid, acetaldehyde.In production conventional distillation and separation method thick acetic acid is carried out pure
Change, also can a certain amount of spent acid mother liquor while obtaining high-purity acetic acid.
Under regular situation, generally spent acid mother liquor is separated further, rectifying extract acetic acid therein, whole mother liquor directly as
Produce waste water and enter wastewater treatment working section.But, still include the compositions such as propionic acid in whole mother liquor, direct emission treatment not only wastes
Propionic acid product therein, also increases the environmental protection treatment pressure of waste water further.If using conventional rectification tower respectively to second
Acid, propionic acid are reclaimed, then need to consume substantial amounts of energy, because energy consumption is excessive, the cost recovery that makes spent acid mother liquor too high,
Therefore, using conventional rectification tower, acetic acid, propionic acid are carried out by recovery and cannot obtain commercial introduction.
Content of the invention
The technical problem to be solved in the invention is to provide one kind to carry out waste acid recovery mother liquor using thermal coupling injection cocurrent tower
Technique, this technique can the acetic acid in waste acid recovery mother liquor and propionic acid simultaneously, and heat utilization ratio is high, energy consumption is low, suitable work
Industryization is promoted.
For solving above-mentioned technical problem, the technical solution adopted in the present invention is：
A kind of spent acid mother liquor reclaiming method of methanol carbonylation synthesis of acetic acid, including acetic acid/propionic acid separation, purification of acetic acid
Refine three steps with propionic acid；The detached equipment of described acetic acid/propionic acid is thermal coupling injection cocurrent tower.
A kind of spent acid mother liquor reclaiming method of methanol carbonylation synthesis of acetic acid, concretely comprises the following steps：
A, acetic acid/propionic acid separates
Spent acid mother liquor is sprayed by thermal coupling in the entrance tower at top of cocurrent tower stripping section and carries out rectifying；By rectifying section tower top
Place's extraction comprises acetic acid and the low boiling gas phase of other low boiling impurity, sends into the process of step B after condensation；By stripping section tower reactor
Extraction comprises propionic acid and the higher boiling liquid phase of other high-boiling-point impurity, sends into the process of step C；
B, purification of acetic acid
It is admitted in 1# rectifying column by the charging aperture in the middle part of tower body from the low boiling gas phase of step A, further
Carry out rectification and purification；Send by the 1# tower bottom of rectifying tower highly purified acetic acid of extraction, through acetic acid output channel, by 1# rectifying tower
At top, the low boiling impurity of extraction is delivered to environmental protection workshop section by low boiling impurity output channel and is post-processed；
C, propionic acid refine
It is admitted in 2# rectifying column by the charging aperture in the middle part of tower body from the higher boiling liquid phase of step A, further
Carry out rectification and purification；Send by the 2# rectifying column tower top highly purified propionic acid of extraction, through propionic acid output channel, by 2# rectifying tower
At kettle, the high-boiling-point impurity of extraction is delivered to environmental protection workshop section by high-boiling-point impurity output channel and is post-processed.
Further improvement of the present invention is：Described step A, step C are atmospheric distillation, and described step B is compression rectification,
Tower is pressed as 200kPa～300kPa.
Further improvement of the present invention is：The reflux ratio of described step A is 12～18, and the reflux ratio of step B is 1～4,
The reflux ratio of step C is 2～6.
Further improvement of the present invention is：The reflux ratio of described step A is 15, and the reflux ratio of step B is 2, step C
Reflux ratio is 4.
Further improvement of the present invention is：It is not less than 99.5% by the acetic acid content that step B produces, produced by step C
Propionic acid content be not less than 99.7%.
Further improvement of the present invention is：Described thermal coupling injection cocurrent tower includes tower body and the continuous mass transfer column of multilayer
Plate, tower body includes outer tower, interior tower within outer tower for the suit, is isolated into rectifying section by the outer wall of interior tower between inner tower and outside tower
And stripping section；When interior tower is rectifying section, outer tower is stripping section；When interior tower is stripping section, outer tower is rectifying section；Every layer continuous
Mass transfer tower board includes column plate, the terraced rectangle calotte above air rising hole and the descending liquid system being provided with air rising hole；Described hot coupling
The bottom of towe closing injection cocurrent tower is provided with the reboiler being connected with stripping section, and its tower top is provided be connected with rectifying section cold
Condenser；
Described outer tower column plate is annular column plate, and the descending liquid system of outer tower is the downspout being arranged alternately, and often covers downspout bag
The down-flow plate I include downflow weir, be arrangeding in parallel and down-flow plate II, form descending liquid passage between down-flow plate I and down-flow plate II, descending liquid is led to
The upper end in road is provided perpendicular to the downflow weir of annular column plate；The upper end of down-flow plate I with positioned at upper strata annular column plate on another
The downflow weir of downspout is connected, its lower end and annular column plate and tower body fixed seal connection；The upper end of down-flow plate II and upper strata
Down-flow plate I lower end of another downspout on annular column plate is connected, and is provided with liquid and flows out between its lower end and annular column plate
Passage；
Described interior tower column plate is circular column plate, the descending liquid system of interior tower include passing through column plate I center central well down take, in
Between seal pot, down flow apron, mozzle and annular seal pot；Middle seal pot and central well down take are respectively provided with circular, centre
Seal pot is located at the lower section of central well down take, and the diameter of central well down take is less than the diameter of middle seal pot, middle seal pot
Periphery, the top perpendicular to middle seal pot have been arranged alternately down flow apron and mozzle；During the bottom level of mozzle is higher than
Between seal pot；The position that central well down take is located at column plate I top is correspondingly provided with central overflow weir；Annular seal pot is located at next
On the circumference of layer column plate, and it is fixedly linked with inlet weir；The outlet of mozzle corresponds in annular seal pot；
The column plate of described rectifying section is to pass through the heat exchange column plate that heat exchange entrance and heat exchange outlet are connected, heat exchange with stripping section
The heat exchange entrance of column plate and heat exchange outlet are located at the mass-transfer zone outside stripping section descending liquid system.
Further improvement of the present invention is：Described heat exchange column plate is the double-deck column plate of hollow or tray surfaces are provided with
The individual layer column plate of heat-transfer pipe, described heat exchanger tube is straight tube, bend pipe, coil pipe or spiral coil；The heat exchange outlet of described heat exchange column plate
Less than heat exchange entrance, heat exchange entrance and heat exchange outlet are located at different mass-transfer zones.
Further improvement of the present invention is：When heat exchange column plate is double-deck column plate, air rising hole run through heat exchange column plate but not
Connect with the inside of heat exchange column plate；When heat exchange column plate is the individual layer column plate being provided with heat-transfer pipe, heat-transfer pipe avoids air rising hole.
Further improvement of the present invention is：The running that cocurrent tower is sprayed in described thermal coupling is：
By stripping section its top feed, after mass transfer heat exchange, the liquid phase reaching stripping section bottom enters one through reboiler to material liquid
High boiling component is produced, the gas isolated in reboiler uses as the gas phase of stripping section after step heating；Reach stripping section top
The gas phase in portion is admitted to rectifying section bottom and carries out mass-and heat-transfer, reaches the gas phase condensed device condensation at rectifying section top, a part
Directly produce as highly purified low boiling component, another part as backflow again from enter rectifying section top, through mass transfer
Discharged and come back to through pipeline the material liquid entrance at stripping section top after heat transfer by rectifying section bottom of towe.
Due to employing technique scheme, the technological progress that the present invention obtains is：
The present invention provides a kind of spent acid mother liquid recovery process of methanol carbonylation synthesis of acetic acid, according to the tool of spent acid mother liquor
Volume property, from suitable separation equipment and determine optimal control parameter, thus to the acetic acid comprising in spent acid mother liquor and
Propionic acid has carried out efficiently separating purification, and the final acetic acid purity obtaining is not less than 99.5%, propionic acid purity and is not less than 99.7%,
Achieve the recycling of spent acid mother liquor；Simultaneously as entering the waste liquid volume minimizing of environmental protection workshop section, acid impurities content pole
Low, therefore, alleviate the intractability of follow-up environmental protection workshop section, environmental protection pressure is low.
Cocurrent tower is sprayed in thermal coupling of the present invention, rectifying section and stripping section is set to the shape of interior tower outer tower suit
Formula, the temperature difference of effectively utilizes stripping section and rectifying section carries out heat exchange at interior tower tower wall, reclaims heat, and is increased by heat exchange column plate
Big heat exchange area, effectively reduces heat dissipation capacity, enhances the heat transfer to rectifying section for the stripping section, thus reaching energy-saving
Purpose, can save energy more than 20% compared with conventional rectifier unit energy consumption, significantly reduce production cost, have very big
Economic benefit and application prospect, suitable industrialization promotion.Simultaneously as rectifying section and stripping section are concentric cylindrical, can be significantly
Reduce tower height and safeguard and production operation it is easy to install.
The rectifying section column plate that cocurrent tower is sprayed in the thermal coupling that the present invention adopts is heat exchange column plate, and the high temperature gas phase of stripping section is entered
Enter heat exchange column plate, the liquid phase feed liquid to flowing on rectifying section column plate heats, significantly increase heat exchange area, improve heat
The utilization rate of amount.The heat exchange entrance of described heat exchange column plate and heat exchange outlet are respectively positioned on the mass-transfer zone outside stripping section descending liquid system,
But heat exchange entrance and heat exchange export not in same mass-transfer zone, are prevented effectively from due to cold and hot gas backmixing and lead in heat exchange column plate
Gas temperature reduce；Described heat exchange outlet is less than heat exchange entrance, and the condensate liquid being easy to heat exchange columns intralamellar part flows out in time, heat exchange
Gas within column plate keeps high temperature, and the heat transfer effect of heat exchange column plate has been effectively ensured.Heat exchange column plate is the double-deck column plate of hollow
Or surface is provided with the individual layer column plate of heat-transfer pipe, and heat-transfer pipe may be selected multiple shapes such as straight tube, bend pipe, coil pipe or spiral coil
Formula, the scope of application is very wide.
Brief description
Fig. 1 is the schematic flow sheet of the present invention；
Fig. 2 is the structural representation that cocurrent tower is sprayed in separation equipment thermal coupling of the present invention；
Fig. 3 is the interior tower descending liquid system structure diagram that cocurrent tower is sprayed in separation equipment thermal coupling of the present invention；
Wherein, 1, thermal coupling injection cocurrent tower, 11, tower body, 131, down-flow plate I, 132, down-flow plate II, 133, descending liquid gear
Plate, 134, central well down take, 135, liquid outflow channel, 136, middle seal pot, 138, annular seal pot, 139, mozzle,
14th, downflow weir, 15, calotte, 16, descending liquid passage, 17, inlet weir, 18, Nei Ta, 19, Wai Ta, 2,1# rectifying column, 3,2# rectifying
Tower, 4, mother liquor conveyance conduit, 5, low boiling impurity output channel, 6, acetic acid output channel, 7, propionic acid output channel, 8, higher boiling
Impurity output channel, 9, reboiler, 10, condenser.
Specific embodiment
With reference to embodiment and accompanying drawing, the present invention is described in further details：
A kind of spent acid mother liquor reclaiming method of methanol carbonylation synthesis of acetic acid, as shown in figure 1, include acetic acid/propionic acid divide
Refine three steps from, purification of acetic acid and propionic acid, the spent acid mother liquor preparing workshop section from acetic acid is through above three step gradually
Separating-purifying, thus obtain content to be more than the acetic acid product that 99.7% propionic acid product and content are more than 99.5%.
Wherein, the separation equipment that acetic acid/propionic acid separating step is used sprays cocurrent tower, purification of acetic acid and third for thermal coupling
The separation equipment that acid treating is used is conventional rectification tower.
The thermal coupling injection cocurrent tower that the present invention uses, as shown in Figure 1 and Figure 2, including cylindrical tower body 11；Tower body 11 wraps
Include the interior tower 18 of cylinder and the outer tower 19 of annular, interior tower 18 is set with outer tower 19；Pass through interior between interior tower 18 and outer tower 19
The outer wall of tower 18 is isolated into rectifying section and stripping section.When within tower 18 be rectifying section when, outer tower 19 be stripping section；When within tower
18 be stripping section when, outer tower 19 be rectifying section.The reboiler 9 of heat is provided in the bottom of towe promising tower body of setting, reboiler 9 with carry
Evaporate a section bottom to be connected；The tower top of rectifying section is provided with condenser 10.
It is arranged with multigroup annular column plate in described outer tower 19 in parallel, multiple air rising holes, calotte are provided with annular column plate
15 are located above air rising hole.Outer tower descending liquid system includes four sets of downspouts being surrounded on interior tower outer wall, and this four sets of downspouts will be outer
Tower equipartition is symmetrical four mass-transfer zone.The down-flow plate I of deflector type that often set downspout includes downflow weir 14, be arranged in parallel
131 and down-flow plate II 132, the passage being formed between down-flow plate I 131 and down-flow plate II 132 is descending liquid passage 16, descending liquid passage 16
Upper end be provided perpendicular to the downflow weir 14 of annular column plate；The upper end of down-flow plate I 131 with positioned at upper strata annular column plate on another
The downflow weir 14 of one downspout is connected, its lower end and annular column plate and tower body fixed seal connection；The upper end of down-flow plate II 132
It is connected with down-flow plate I 131 lower end of another downspout on the annular column plate of upper strata, be provided between its lower end and annular column plate
Liquid outflow channel 135.
It is arranged with multigroup circle column plate in described interior tower 18 in parallel, multiple air rising holes, calotte are provided with circular column plate
15 are arranged above air rising hole.The descending liquid system of interior tower 18 includes passing through the central well down take 134 at column plate center, middle seal pot
136th, down flow apron 133, mozzle 139 and annular seal pot 138；Middle seal pot 136 and central well down take 134 are all provided with being set to
Circle, middle seal pot 136 is located at the lower section of central well down take 134, and the diameter of central well down take 134 is less than middle seal pot
136 diameter, the periphery of middle seal pot 136, has been arranged alternately down flow apron 133 perpendicular to the top of middle seal pot 136
With mozzle 139；Mozzle 139 is upper shed type groove steel, and the bottom level of mozzle 139 is higher than middle seal pot 136；Center
The position that downspout 134 is located above column plate is correspondingly provided with central overflow weir；Annular seal pot 138 is located at next layer of column plate
On circumference, in plate, and it is connected with inlet weir 17；The outlet of mozzle corresponds in annular seal pot 138.
The column plate of described rectifying section is heat exchange column plate, and heat exchange column plate is connected with stripping section with heat exchange outlet by heat exchange entrance
Logical.The heat exchange entrance of heat exchange column plate and heat exchange outlet are located at the mass-transfer zone outside stripping section descending liquid system, and the changing of heat exchange column plate
Hot entrance and heat exchange outlet are located at different mass-transfer zones, to avoid cold and hot gas backmixing.Described heat exchange outlet enters less than heat exchange
Mouthful, it is easy to condensate liquid and flow out.
Described heat exchange column plate can be selected for the double-deck column plate of hollow, air rising hole run through heat exchange column plate but not with heat exchange column plate in
Portion connects；Described heat exchange column plate also can be selected for the individual layer column plate that surface is provided with heat-transfer pipe, and heat-transfer pipe passes through tube wall and individual layer tower
Plate contacts, and air rising hole is avoided in the position of heat-transfer pipe.It is many that described heat exchanger tube can be selected for straight tube, bend pipe, coil pipe or spiral coil etc.
Plant arrangement.
The running that cocurrent tower is sprayed in described thermal coupling is：
By stripping section its top feed, after mass transfer heat exchange, the liquid phase reaching stripping section bottom enters one through reboiler to material liquid
High boiling component is produced, the gas isolated in reboiler uses as the gas phase of stripping section after step heating；Reach stripping section top
The gas phase in portion is admitted to rectifying section bottom and carries out mass-and heat-transfer, reaches the gas phase condensed device condensation at rectifying section top, a part
Directly produce as highly purified low boiling component, another part as backflow again from enter rectifying section top, through mass transfer
Discharged and come back to through pipeline the material liquid entrance at stripping section top after heat transfer by rectifying section bottom of towe.
Using thermal coupling injection cocurrent tower, spent acid mother liquor is reclaimed.The thermal coupling injection cocurrent that the present embodiment is used
In tower, interior tower is rectifying section, and outer tower is stripping section.
The concrete technology step of the spent acid mother liquid recovery process of methanol carbonylation synthesis of acetic acid is：
A, acetic acid/propionic acid separates
Spray the feed(raw material)inlet at outer tower 19 top of cocurrent tower 1 from the spent acid mother liquor of mother liquor conveyance conduit 4 by thermal coupling
Enter stripping section and move downward, moved upwards by bottom of towe by the gas phase that reboiler 9 provides, the gas of the liquid phase of decline and rising
Carry out partial gasification and partial condensation at each block of annular column plate, the low-boiling point material such as acetic acid gradually gasifies entrance gas phase,
The high boiling substances such as propionic acid remain in liquid phase.Propionic acid and other high-boiling-point impurity is comprised in the liquid phase reaching outer tower 19 bottom of towe,
Discharge after heating further through reboiler 9 and send into 2# rectifying column 3 through pipeline and refine further；Reach the gas of outer tower 19 tower top
Body is admitted to interior tower 18 bottom and carries out rectifying, includes the low boilings such as iodide, acetic acid and water by the gas phase of interior tower 1 overhead extraction
Material, produces after condensed device 10 condensation and refines further through pipeline feeding 1# rectifying column 2.
B, purification of acetic acid
The low boiling condensate liquid spraying tower 18 overhead extraction in cocurrent tower 1 from the thermal coupling of step A is admitted to 1# rectifying column 2
Middle part and move downward, the gas phase from reboiler 9 is moved upwards；The liquid phase declining is entered at column plate with the gas phase rising
Row partial gasification and partial condensation, iodide, water and a small amount of acetic acid gradually gasify entrance gas phase, and acetic acid is progressively enriched with liquid phase
In, produced by tower reactor.
By the acetic acid content up to more than 99.5% of 1# rectifying column 2 tower reactor extraction, directly can be adopted by acetic acid output channel 6
Go out application.Condensed by the condensed device of low boiling impurity 10 of 1# rectifying column 2 overhead extraction, a part of condensate liquid returns as backflow
1# rectifying column 2 tower top, another part condensate liquid is delivered to environmental protection workshop section by low boiling impurity output channel 5 and is post-processed.
C, propionic acid refine
The higher boiling liquid phase spraying the extraction of cocurrent tower 1 outer tower 19 tower reactor from the thermal coupling of step A is admitted to 2# rectifying column 3
Middle part simultaneously moves downward, and the gas phase from reboiler 9 is moved upwards；The liquid phase declining is carried out at column plate with the gas phase rising
Partial gasification and partial condensation, propionic acid gradually gasifies entrance gas phase, other high-boiling-point impurities be progressively enriched with the liquid phase, by tower reactor
Extraction.
Condensed by the condensed device of propionic acid gas 10 of 2# rectifying column 3 overhead extraction, the propionic acid content in gained condensate liquid is up to
More than 99.7%；A part of condensate liquid directly produces application by propionic acid output channel 7, and another part condensate liquid returns as backflow
Return 2# rectifying column 3 tower top.Ring is delivered to by high-boiling-point impurity output channel 8 by the high-boiling-point impurity of 2# rectifying column 3 tower reactor extraction
Protect workshop section to be post-processed.
During spent acid disposing mother liquor, step A and step B are atmospheric operation, and step C is pressurized operation, operation pressure
Power is 150～300kPa.Distillation operation mode can adopt continuous rectification, batch fractionating, semicontinuous rectifying one of which, preferably
Continuous rectification.The reflux ratio of described step A is 12～18, and the reflux ratio of step B is 1～4, and the reflux ratio of step C is 2～6.
Embodiment 1
The raw material composition of pending spent acid mother liquor and its weight/mass percentage composition are：
Propionic acid 35.73%, acetic acid 39.16%, water 12.84%, methyl iodide 0.62%, iodide ion 0.64%, other
11.01%.
Spent acid disposing mother liquor process is：
A, acetic acid/propionic acid separates
Spent acid mother liquor is admitted to thermal coupling injection cocurrent tower and carries out rectifying separation, and rectifying mode is atmospheric distillation, reflux ratio
From 15.Spent acid mother liquor completes acetic acid and separates with the mass transfer of propionic acid in thermal coupling injection cocurrent tower, because acetic acid boiling point is relatively low,
Propionic acid boiling point is higher, and therefore, acetic acid constantly gasifies entrance gas phase, and propionic acid stays in the liquid phase.
The tower top temperature that cocurrent tower is sprayed in thermal coupling is 103 DEG C about.Iodide, second are included by the gas phase of overhead extraction
The low-boiling point material such as acid and water, condensed device condenses and then sends into 1# rectifying column by pipeline and refines further.
The bottom temperature that cocurrent tower is sprayed in thermal coupling is 116 DEG C about.By the liquid phase that tower reactor produces include propionic acid and its
His high-boiling-point impurity.Described liquid phase is sent into 2# rectifying column by pipeline and is refined further.
B, purification of acetic acid
It is admitted to 1# rectifying column from the low boiling condensate liquid of step A and carry out further rectifying separation；Rectifying mode is to add
Pressure rectifying, tower is pressed as 200kPa～300kPa, and reflux ratio selects 2.In 1# rectifying column, the relatively low iodide of boiling point, water and few
Amount acetic acid gradually gasify entrance gas phase, move upwards, acetic acid be progressively enriched with the liquid phase, flow downward.
The tower top temperature of 1# rectifying column is 117～131 DEG C.It is low boiling impurity by the gas phase of overhead extraction, including iodate
Thing, water and a small amount of acetic acid.After condensed device condensation, a part of condensate liquid returns 1# rectifying column tower top, another part as backflow
Condensate liquid is delivered to environmental protection workshop section and is post-processed.
The bottom temperature of 1# rectifying column is 156～168 DEG C.The liquid phase being produced by tower reactor is content up to more than 99.5%
Acetic acid, can directly produce application.
C, propionic acid refine
It is admitted to 2# rectifying column from the higher boiling liquid phase of step A and carry out further rectifying separation；Rectifying mode is normal pressure
Rectifying, reflux ratio selects 4.In 2# rectifying column, the relatively low propionic acid of boiling point gradually gasifies and enters gas phase, moves upwards, and other are high
Boiling contaminants be progressively enriched with the liquid phase, flow downward.
The tower top temperature of 2# rectifying column is 141 DEG C about.99.7% propionic acid is more than by the gas phase of overhead extraction for content；
Gas phase condenses through condenser, and a part of condensate liquid returns 2# rectifying column tower top as backflow, and another part condensate liquid is directly adopted
Go out application.
The bottom temperature of 2# rectifying column is 194 DEG C.The liquid phase being produced by tower reactor is high-boiling-point impurity, is fed directly to environmental protection work
Duan Jinhang post-processes.
In above-mentioned steps A, when the separating effect of acetic acid/propionic acid is identical, spray cocurrent tower and use using thermal coupling
The energy consumption of conventional rectification tower is as shown in table 1.
The energy consumption comparison of cocurrent tower and conventional rectification tower is sprayed in table 1 thermal coupling
| Cocurrent tower is sprayed in thermal coupling | Conventional rectification tower | |
| Refrigeration duty (kW/h) | 419.29 | 529.61 |
| Thermic load (kW/h) | 376.78 | 478.28 |
| Total load (kW/h) | 796.07 | 1007.89 |
Be can be seen that by data in table 1 and carry out rectifying using thermal coupling injection cocurrent tower, its thermic load, refrigeration duty are all bright
Show and be less than conventional rectification tower.Compared with conventional rectification tower, the total load that cocurrent tower is sprayed in thermal coupling reduces 211.82kW/h, section
Amplitude can reach more than 21%, energy-saving effect is very notable.
Claims (7)
1. a kind of spent acid mother liquor reclaiming method of methanol carbonylation synthesis of acetic acid it is characterised in that：Divide including acetic acid/propionic acid
Refine three steps from, purification of acetic acid and propionic acid；The detached equipment of described acetic acid/propionic acid is thermal coupling injection cocurrent tower (1)；Tool
Body step is：
A, acetic acid/propionic acid separates
Spent acid mother liquor is entered in tower by the top that cocurrent tower (1) stripping section is sprayed in thermal coupling and carries out atmospheric distillation；By rectifying section tower
At top, extraction comprises acetic acid and the low boiling gas phase of other low boiling impurity, sends into the process of step B after condensation；By stripping section tower reactor
Place's extraction comprises propionic acid and the higher boiling liquid phase of other high-boiling-point impurity, sends into the process of step C；
B, purification of acetic acid
It is admitted to by the charging aperture in the middle part of tower body in 1# rectifying column (2), presses in tower from the low boiling gas phase of step A and be
200kPa～300kPa carries out compression rectification purification further；By 1# rectifying column (2) the tower reactor highly purified acetic acid of extraction, through second
Sour output channel (6) is sent, and passes through low boiling impurity output channel by the low boiling impurity of 1# rectifying column (2) tower top extraction
(5) deliver to environmental protection workshop section to be post-processed；
C, propionic acid refine
It is admitted to by the charging aperture in the middle part of tower body in 2# rectifying column (3), enters further from the higher boiling liquid phase of step A
Row atmospheric distillation purifies；Send by 2# rectifying column (3) the tower top highly purified propionic acid of extraction, through propionic acid output channel (7), by 2#
At rectifying column (3) tower reactor, the high-boiling-point impurity of extraction delivers to place after environmental protection workshop section is carried out by high-boiling-point impurity output channel (8)
Reason；
Described thermal coupling injection cocurrent tower (1) includes tower body (11) and the continuous mass transfer tower board of multilayer, and tower body (11) includes outer tower
(19), suit is in the internal interior tower (18) of Wai Ta (19), between interior tower (18) and outer tower (19) by the outer wall of interior tower (18) every
From one-tenth rectifying section and stripping section；When interior tower (18) is rectifying section, outer tower (19) is stripping section；When interior tower (18) is stripping section
When, outer tower (19) is rectifying section；Every layer of continuous mass transfer tower board includes column plate, the ladder above air rising hole being provided with air rising hole
Rectangle calotte (15) and descending liquid system；The bottom of towe of described thermal coupling injection cocurrent tower (1) is provided with and is connected with stripping section again
Boiling device (9), its tower top is provided with the condenser (10) being connected with rectifying section；
Described outer tower (19) column plate is annular column plate, and the descending liquid system of outer tower (19) is the downspout being arranged alternately, and often covers descending liquid
Pipe includes downflow weir (14), be arranged in parallel down-flow plate I (131) and down-flow plate II (132), down-flow plate I (131) and down-flow plate II
(132) form descending liquid passage (16) between, the upper end of descending liquid passage (16) is provided perpendicular to the downflow weir (14) of annular column plate；
The upper end of down-flow plate I (131) is connected with the downflow weir (14) of another downspout on the annular column plate of upper strata, its lower end with
Annular column plate and tower body fixed seal connection；Another downspout on the annular column plate with upper strata of the upper end of down-flow plate II (132)
Down-flow plate I (131) lower end is connected, and is provided with liquid outflow channel (135) between its lower end and annular column plate；
Described interior tower (18) column plate is circular column plate, and the descending liquid system of interior tower (18) includes passing through the center descending liquid at column plate I center
Pipe (134), middle seal pot (136), down flow apron (133), mozzle (139) and annular seal pot (138)；Middle seal pot
(136) and central well down take (134) be respectively provided with circular, middle seal pot (136) be located at central well down take (134) lower section,
The diameter of central well down take (134) is less than the diameter of middle seal pot (136), the periphery of middle seal pot (136), perpendicular in
Between the top of seal pot (136) be arranged alternately down flow apron (133) and mozzle (139)；The bottom level of mozzle (139)
Higher than middle seal pot (136)；The position that central well down take (134) is located at column plate I top is correspondingly provided with central overflow weir；Ring
Shape seal pot (138) is located on the circumference of next layer of column plate, and is fixedly linked with inlet weir (17)；The outlet of mozzle (139)
Correspond in annular seal pot (138)；
The column plate of described rectifying section is to pass through the heat exchange column plate that heat exchange entrance and heat exchange outlet are connected, heat exchange column plate with stripping section
Heat exchange entrance and heat exchange outlet be located at stripping section descending liquid system outside mass-transfer zone.
2. methanol carbonylation synthesis of acetic acid according to claim 1 spent acid mother liquor reclaiming method it is characterised in that：Institute
The reflux ratio stating step A is 12～18, and the reflux ratio of step B is 1～4, and the reflux ratio of step C is 2～6.
3. methanol carbonylation synthesis of acetic acid according to claim 2 spent acid mother liquor reclaiming method it is characterised in that：Institute
The reflux ratio stating step A is 15, and the reflux ratio of step B is 2, and the reflux ratio of step C is 4.
4. the spent acid mother liquor reclaiming method of the methanol carbonylation synthesis of acetic acid according to any one of claims 1 to 3, it is special
Levy and be：It is not less than 99.5% by the acetic acid content that step B produces, be not less than 99.7% by the propionic acid content that step C produces.
5. methanol carbonylation synthesis of acetic acid according to claim 1 spent acid mother liquor reclaiming method it is characterised in that：Institute
State the double-deck column plate that heat exchange column plate is hollow or tray surfaces are provided with the individual layer column plate of heat-transfer pipe, described heat-transfer pipe is straight
Pipe, bend pipe, coil pipe or spiral coil；The heat exchange outlet of described heat exchange column plate is less than heat exchange entrance, heat exchange entrance and heat exchange outlet
Positioned at different mass-transfer zones.
6. methanol carbonylation synthesis of acetic acid according to claim 5 spent acid mother liquor reclaiming method it is characterised in that：When
When heat exchange column plate is double-deck column plate, air rising hole is run through heat exchange column plate but is not connected with the inside of heat exchange column plate；When heat exchange column plate is
Be provided with heat-transfer pipe individual layer column plate when, heat-transfer pipe avoids air rising hole.
7. the spent acid mother liquor reclaiming method of methanol carbonylation synthesis of acetic acid according to claim 1 is it is characterised in that institute
State thermal coupling spray cocurrent tower running be：
By stripping section its top feed, after mass transfer heat exchange, the liquid phase reaching stripping section bottom adds further material liquid through reboiler
High boiling component is produced, the gas isolated in reboiler uses as the gas phase of stripping section after heat；Reach stripping section top
Gas phase is admitted to rectifying section bottom and carries out mass-and heat-transfer, reaches the gas phase condensed device condensation at rectifying section top, a part of conduct
Highly purified low boiling component directly produces, another part as backflow again from enter rectifying section top, through mass-and heat-transfer
Discharged and come back to through pipeline the material liquid entrance at stripping section top afterwards by rectifying section bottom of towe.
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|---|---|---|---|---|
| CN102307841A (en) * | 2008-12-08 | 2012-01-04 | 莱昂德尔化学技术公司 | Preparation of acetic acid |
| CN103249705A (en) * | 2010-10-06 | 2013-08-14 | 株式会社大赛璐 | Acetic acid production method |
| CN104001343A (en) * | 2014-05-14 | 2014-08-27 | 华南理工大学 | Internal heat-integration rectification tower having heat transfer strengthened |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102307841A (en) * | 2008-12-08 | 2012-01-04 | 莱昂德尔化学技术公司 | Preparation of acetic acid |
| CN103249705A (en) * | 2010-10-06 | 2013-08-14 | 株式会社大赛璐 | Acetic acid production method |
| CN104001343A (en) * | 2014-05-14 | 2014-08-27 | 华南理工大学 | Internal heat-integration rectification tower having heat transfer strengthened |
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