CN105503655B - A kind of acid number reduction device for heavy solvent method TDI products - Google Patents
A kind of acid number reduction device for heavy solvent method TDI products Download PDFInfo
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- CN105503655B CN105503655B CN201510932871.1A CN201510932871A CN105503655B CN 105503655 B CN105503655 B CN 105503655B CN 201510932871 A CN201510932871 A CN 201510932871A CN 105503655 B CN105503655 B CN 105503655B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/18—Separation; Purification; Stabilisation; Use of additives
- C07C263/20—Separation; Purification
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Abstract
The invention belongs to chemical production technical field, it is related to a kind of reduction device for heavy solvent method TDI product acid numbers, the connection of feed preheater duct type butts up against the middle part of product tower to realize the preheating of photochemical reaction material, product top of tower be connected with product tower condenser for condense recovery TDI products, the reboiler that product tower bottom communication type is set is used to vaporize backflow, product tower bottom is connected in order to purge acidic components by kettle liquid pump with purge column duct type, and reboiler, kettle liquid pump are connected with the handing-over of purge column three duct type；Purge column top be connected with purge column condenser for condense recovery acidic components；The distribution apparatus of the atomizing structure set in the inner chamber of purge column top and bottom is used to be distributed heavy solvent dimethyl isophthalate and inert gas；On each device, it is separately provided for transmitting the pipeline and its port of each material；Single unit system design science, rational in infrastructure, simple to operate, easy to use, applied environment is good.
Description
Technical field：
The invention belongs to chemical production technical field, it is related to a kind of reduction device for heavy solvent method TDI product acid numbers,
Circulation solvent can be reduced and return to the generation that front-end-of-line participates in accessory substance during photochemical reaction, so as to improve photochemical reaction efficiency
With the stability of system.
Background technology：
Toluene di-isocyanate(TDI) (abbreviation TDI below) is industrial common as a kind of important isocyanates product
Preparation method have light phosgenation, nitro compound carbonylation method and dimethyl carbonate method, wherein light phosgenation is typically adopted
Use the following two kinds technique：One kind is to make solvent with dimethyl isophthalate (equal vehicle economy IP below), is entered under elevated pressure conditions
Row photochemical reaction, referred to as " heavy solvent method "；Another kind is to make solvent with o-dichlorohenzene (ODCB) etc., and light is carried out under lower pressure
Change reaction, referred to as " light naphtha method "；Because there is notable difference, therefore each comfortable light in the TDI production processes of above two method
The physical property of the acidic components of side reaction genesis mechanism and generation when changing reaction is also not quite similar.
The acidic components produced during light naphtha method production TDI are mainly the material lighter than TDI, using rectifying or inertia
The mode that gas directly purges the product containing certain proportion solvent can be just enriched in gas phase, so as to realize acid group
Divide the purpose for TDI products separate；Can in a kind of such as disclosed in Chinese patent 92100452.4 reduction toluene di-isocyanate(TDI)
Proposed in the method for hydrolyzable chloride content, when from ortho-xylene as solvent, to being passed through nitrogen or chlorination in TDI products
Hydrogen, 1-3h is stopped after being heated to 160-200 DEG C can significantly reduce acidic components content；A kind of essence is also disclosed in the patent
The method for evaporating, i.e., during from o-dichlorohenzene as solvent, be heated to 180-195 DEG C and reach total reflux and make gained mixture point
Evaporate, can just reach reduces the purpose of product acidity constituent content.
The acidic components produced during heavy solvent method production TDI mainly have hydrogen chloride, the benzyl position isocyanic acid of chlorotoluene two
Ester (abbreviation Cl-TDI below), m- ethyl esters chlorobenzoyl chloride (abbreviation CBC below) etc., the boiling point of wherein Cl-TDI and CBC are situated between
Between product TDI and solvent DEIP, in product purification operation, product with solvent is separated in final product tower
, on the one hand, if acidic components are produced with heavy solvent from tower reactor, because solvent wants return system to recycle, acidic components
In the presence of the generation that can then cause more photochemical side reactions so that the generation accessory substance such as residue, influence reaction yield and system it is steady
Fixed operation；If acidic components are entered into product from overhead extraction, belong to heavy constituent relative to TDI, now according to rectifying
Or then can be brought into large-tonnage product in the middle of gas phase by the method for purging, this is higher to equipment size and horsepower requirements, and not
Rationally effectively acidic components can be separated.Therefore, the more applicable rectification method of light naphtha method and gas sweeping method for
Heavy solvent method production TDI products in acidic components removal and do not apply to.
In addition, in the prior art there is a kind of TDI products acid number and acidic components content of being reduced by additional substance
Method, such as United States Patent (USP) US6395925 propose to adding a kind of such as alcohols material such as methyl alcohol, ethanol in isocyanates,
It is then heated to more than 180 DEG C, heat time preferred more than 240min can significantly reduce containing for acidic components in isocyanates
Amount；Although the method for above-mentioned additional substance can preferably remove the acidic components in product, introduce again simultaneously a kind of new
Impurity composition, also need to be purged by nitrogen afterwards, the method such as rectifying or extraction separates it from product, virtually
Workload is increased again.Therefore acid number and acidic components content a kind of production TDI products suitable for heavy solvent method are designed
New reduction device, can effectively reduce the content of acidic components in circulation solvent, the quality of product TDI be improved, with good
Application value and put into practice benefit.
The content of the invention：
It is an object of the invention to the shortcoming for overcoming prior art to exist, seek design a kind of for heavy solvent method TDI products
The reduction device of product acid number, can not only reduce the acid number of product TDI, and can make the acidic components content in circulation solvent
Substantially reduce.
To achieve these goals, heavy solvent method TDI (abbreviation of toluene di-isocyanate(TDI)) product acid of the present invention
Value reduction apparatus main body structure includes feed preheater, product tower, product tower condenser, reboiler, kettle liquid pump, purge column, blows
Tower condenser and distribution apparatus are swept, the connection of feed preheater duct type butts up against the middle part of product tower to realize photochemical reaction material
Preheating, product top of tower be connected with product tower condenser for condense reclaim TDI products, product tower bottom communication type setting
Reboiler is used to vaporize backflow, and product tower bottom is connected in order to purge acidic components by kettle liquid pump with purge column duct type,
Reboiler, kettle liquid pump are connected with the handing-over of purge column three duct type；Purge column top is connected with purge column condenser for condensing
Reclaim acidic components；Between the distribution apparatus of the atomizing structure set in the inner chamber of purge column top and bottom is used to be distributed heavy solvent
Diethyl phthalate (DEIP) and inert gas；On each device, it is separately provided for transmitting each material (including photochemical anti-
Answer logistics, fixed gas logistics, TDI product streams, reflux stream, solvent DEIP logistics, inert gas stream, fixed gas logistics,
Acidic components logistics and circulation solvent stream) pipeline and its port so that each logistics is smooth current according to principle, with reality
Now reduce heavy solvent method TDI products acid number and reduce the technique effect of acidic components in circulation solvent.
Preferably, realize reducing heavy solvent method TDI product acid numbers in the heavy solvent method TDI products acid number reduction device
Method specifically includes following steps：
(1) the photochemical reaction material that heavy solvent method prepares toluene di-isocyanate(TDI) (TDI) is preheated to through feed preheater
Sent into after 160~190 DEG C in product tower, control pressure is 0.5~20kpaA, temperature is 170~240 DEG C；Gas in product tower
Enter in product tower condenser through product top of tower, 40~100 DEG C of temperature of control is condensed, and fixed gas material is from product tower
The top gas phase of condenser is produced to the vacuum system of peripheral hardware, and a part of material for condensing out is returned in product tower through reboiler
Used as backflow, reflux ratio is 1.5~15, and another part material for condensing out is used as toluene di-isocyanate(TDI) (TDI) product liquid
Mutually produce；Toluene di-isocyanate(TDI) (TDI) the product acid number of extraction is controlled to be less than 10ppm so that most of acidic components are with weight
Solvent dimethyl isophthalate (DEIP) is produced from product tower, realizes acidic components and toluene di-isocyanate(TDI) (TDI) product
Separation；
(2) from the heavy solvent dimethyl isophthalate (DEIP) that the acid number of product tower extraction is 50~140ppm, through kettle
Liquid pump is sent directly into purge column after boosting to 2~6bar, and control pressure is 0~30kpa, temperature is 160~200 DEG C；Weight is molten
Agent dimethyl isophthalate (DEIP) after being distributed through the distribution apparatus in purge column top it is uniform be sprayed in purge column and
Flowed under Action of Gravity Field, inert gas is uniformly blown into purge column through purging after the distribution apparatus of tower bottom is distributed, in tower
The heavy solvent dimethyl isophthalate (DEIP) for flowing from top to bottom is mutually fully contacted；
(3) acidic components in heavy solvent dimethyl isophthalate (DEIP), the catabolite of acidic components and other
Volatile components are enriched with to purging column overhead with inert gas and are entered in purge column condenser with gas phase, and it is 40~80 to control temperature
DEG C condensed, fixed gas material is produced to the vacuum system of peripheral hardware from purge column condenser overhead gas phase, the acid for condensing out
Property component, the catabolite of acidic components and other volatile components through purge column condenser bottom liquid phases produce, from purge column
Bottom is obtained circulation solvent of the acid number less than 50ppm and is recycled with Returning process, so as to improve photochemical reaction efficiency to reduce light
Change the accessory substance generated during reaction.
Further, the photochemical reaction material that heavy solvent method prepares TDI in the step of being related to (1) is 30~100ppm of acid number
(in terms of HCl, similarly hereinafter) contains toluene di-isocyanate(TDI) (TDI), heavy solvent dimethyl isophthalate (DEIP), acidic components
With the material of other impurities, it is stripped of hydrogen chloride, phosgene and residue component；The inert gas being related to is nitrogen, carbon dioxide
Or hydrogen chloride, its pressure is 1~10bar, is 0.5~5 with the mol ratio of heavy solvent dimethyl isophthalate (DEIP).
The present invention compared with prior art, when being prepared by heavy solvent method into TDI first with product tower in photochemical reaction mass
Acidic components are produced, and recycle the method for inert gas purge solvent that acidic components are isolated from solvent in purge column
Go, so as to obtain the TDI products of relatively low acid number, while also reducing the content of acidic components in circulation solvent, improve photochemical
The stability of reaction efficiency and system；Single unit system design science, rational in infrastructure, simple to operate, easy to use, applied environment is good
It is good.
Brief description of the drawings：
Fig. 1 is heavy solvent method TDI products acid number of the present invention reduction apparatus structure and its principle process schematic diagram.
Specific embodiment：
The present invention is described further below by embodiment and with reference to accompanying drawing.
Embodiment 1：
The heavy solvent method TDI products acid number reduction apparatus main body structure that the present embodiment is related to includes feed preheater 1, product
Tower 2, product tower condenser 3, reboiler 4, kettle liquid pump 5, purge column 6, purge column condenser 7 and distribution apparatus 8, feed preheater
The connection of 1 duct type butts up against the middle part of product tower 2 to realize the preheating of photochemical reaction material, and the top of product tower 2 is connected with product
Tower condenser 3 is used to condense recovery TDI products, and the reboiler 4 that the bottom communication type of product tower 2 is set flows back for vaporizing, product
The bottom of tower 2 is connected in order to purge acidic components, reboiler 4, kettle liquid pump 5 and purging by kettle liquid pump 5 with the duct type of purge column 6
The handing-over connection of the three's duct type of tower 6；The top of purge column 6 be connected with purge column condenser 7 for condense recovery acidic components；Purging
The distribution apparatus 8 of the atomizing structure set in the top and bottom inner chamber of tower 6 is used to be distributed heavy solvent dimethyl isophthalate
And inert gas (DEIP)；On each device, it is separately provided for transmitting each material (including photochemical reaction material flow A, fixed gas
Flow B, TDI product streams C, reflux stream D, solvent DEIP logistics E, inert gas stream F, fixed gas logistics G, acidic components
Logistics H and circulation solvent stream I) pipeline and its port so that each logistics is smooth current according to principle, to realize reducing
The technique effect of acidic components in heavy solvent method TDI products acid number and reduction circulation solvent.
Feed preheater 1, product tower condenser 3, reboiler 4 and the purge column condenser 7 used in the present embodiment are
Conventional components in this area, related products tower 2 and purge column 6 use packed tower of the prior art or plate column, its
Internal upper and lower ends carry distribution apparatus 8；The kettle liquid pump 5 being related to is pneumatic diaphragm pump；Equipped with connecting accordingly on each part
Formula pipeline reduces apparatus system to constitute acid number.
Embodiment 2：
The present embodiment is implemented in the acid number reduction device of embodiment 1, the reduction heavy solvent method TDI product acid numbers being related to
Method specifically includes following steps：
(1) the photochemical reaction material that heavy solvent method prepares toluene di-isocyanate(TDI) (TDI) is preheated to through feed preheater 1
Sent into after 160~190 DEG C in product tower 2, control pressure is 0.5~20kpaA, temperature is 170~240 DEG C；In product tower 2
Gas phase enters in product tower condenser 3 through the top of product tower 2, and 40~100 DEG C of temperature of control is condensed, and fixed gas material is from product
The top gas phase of product tower condenser 3 is produced to the vacuum system of peripheral hardware, and a part of material for condensing out is returned through reboiler 4 and produced
As backflow in product tower 2, reflux ratio is 1.5~15, and another part material for condensing out is used as toluene di-isocyanate(TDI) (TDI)
Product liquid phase is produced；Toluene di-isocyanate(TDI) (TDI) the product acid number of extraction is controlled to be less than 10ppm so that most of acidity group
Divide and produced from product tower 2 with heavy solvent dimethyl isophthalate (DEIP), realize acidic components and toluene di-isocyanate(TDI)
(TDI) separation of product；
(2) from the heavy solvent dimethyl isophthalate (DEIP) that the acid number of the extraction of product tower 2 is 50~140ppm, through kettle
Liquid pump 5 is sent directly into purge column 6 after boosting to 2~6bar, and control pressure is 0~30kpa, temperature is 160~200 DEG C；Weight
Solvent dimethyl isophthalate (DEIP) is uniformly sprayed in purge column 6 after being distributed through the distribution apparatus 8 in the top of purge column 6
And flow under gravity, inert gas is uniformly blown into purge column 6 after being distributed through the distribution apparatus of the bottom of purge column 6,
Mutually it is fully contacted with the heavy solvent dimethyl isophthalate (DEIP) flowed from top to bottom in tower；
(3) acidic components in heavy solvent dimethyl isophthalate (DEIP), the catabolite of acidic components and other
Volatile components with inert gas be enriched with to the tower top of purge column 6 with gas phase enter purge column condenser 7 in, control temperature be 40~
80 DEG C are condensed, and fixed gas material is produced to the vacuum system of peripheral hardware from the top gas phase of purge column condenser 7, is condensed out
Acidic components, the catabolite of acidic components and other volatile components are produced through the bottom liquid phases of purge column condenser 7, from purging
The bottom of tower 6 is obtained circulation solvent of the acid number less than 50ppm and is recycled with Returning process, so as to improve photochemical reaction efficiency to reduce
The accessory substance generated during photochemical reaction.
The photochemical reaction material that heavy solvent method prepares TDI in the step of the present embodiment is related to (1) is 30~100ppm of acid number
(in terms of HCl, similarly hereinafter) contains toluene di-isocyanate(TDI) (TDI), heavy solvent dimethyl isophthalate (DEIP), acidic components
With the material of other impurities, it is stripped of hydrogen chloride, phosgene and residue component；The inert gas being related to is nitrogen, carbon dioxide
Or hydrogen chloride, its pressure is 1~10bar, is 0.5~5 with the mol ratio of heavy solvent dimethyl isophthalate (DEIP).
Each material is analyzed and can obtained after stabilization to be operated in the present embodiment：The acid number of TDI products is significantly reduced, energy
Enough reach the acid number requirement of high-quality product；The content of acidic components is substantially reduced in circulation solvent, can be reduced it and be returned to
Front-end-of-line participates in the accessory substance generated during photochemical reaction, to improve the stability of photochemical reaction efficiency and system.
The above, specific embodiment only of the invention, but protection scope of the present invention is not limited thereto；It is any
Belong to those skilled in the art the invention discloses technical scope in, the change or replacement that can be readily occurred in, all should
It is included within the scope of the present invention.
Claims (4)
1. a kind of acid number reduction device for heavy solvent method TDI products, it is characterised in that agent structure include feed preheater,
Product tower, product tower condenser, reboiler, kettle liquid pump, purge column, purge column condenser and distribution apparatus, feed preheater pipe
Formula connection in road butts up against the middle part of product tower to realize the preheating of photochemical reaction material, and product top of tower is connected with the condensation of product tower
Device is used to condense recovery TDI products, and the reboiler that product tower bottom communication type is set flows back for vaporizing, and product tower bottom passes through
Kettle liquid pump is connected with purge column duct type in order to purge acidic components, and reboiler, kettle liquid pump and purge column three duct type are handed over
Lead in succession；Purge column top be connected with purge column condenser for condense recovery acidic components；Purge column top and bottom inner chamber
The distribution apparatus of the atomizing structure of middle setting is used to be distributed heavy solvent dimethyl isophthalate and inert gas；In each device
On, it is separately provided for transmitting the pipeline and its port of each material, so that each logistics is smooth current, to realize reducing weight
The technique effect of acidic components in solvent method TDI products acid number and reduction circulation solvent；It is described for heavy solvent method TDI products
Acid number reduction device realizes that the method for reducing heavy solvent method TDI product acid numbers specifically includes following steps：
(1) the photochemical reaction material that heavy solvent method prepares toluene di-isocyanate(TDI) is preheated to 160~190 DEG C through feed preheater
Afterwards in feeding product tower, control pressure is 0.5~20kpaA, and temperature is 170~240 DEG C；Gas phase in product tower is through product tower
Top enters in product tower condenser, and 40~100 DEG C of temperature of control is condensed, and fixed gas material is from the top of product tower condenser
Portion's gas phase is produced to the vacuum system of peripheral hardware, and a part of material for condensing out is returned as backflow in product tower through reboiler,
Reflux ratio is 1.5~15, and another part material for condensing out is produced as TDI products liquid phase；Control the TDI product acids of extraction
Value is less than 10ppm so that most of acidic components are produced with heavy solvent dimethyl isophthalate from product tower, realizes acid group
Divide and separated with TDI products；
(2) from the heavy solvent dimethyl isophthalate that the acid number of product tower extraction is 50~140ppm, 2 are boosted to through kettle liquid pump
It is sent directly into purge column after~6bar, control pressure is 0~30kpa, temperature is 160~200 DEG C；Heavy solvent M-phthalic acid
Diethylester is uniformly sprayed in purge column and flows under gravity, inertia after being distributed through the distribution apparatus in purge column top
Gas is uniformly blown into purge column through purging after the distribution apparatus of tower bottom is distributed, with the heavy solvent that flows from top to bottom in tower
Dimethyl isophthalate is mutually fully contacted；
(3) acidic components in heavy solvent dimethyl isophthalate, the catabolite of acidic components and other volatile components
With inert gas be enriched with to purging column overhead with gas phase enter purge column condenser in, control temperature for 40~80 DEG C carry out it is cold
Solidifying, fixed gas material is produced to the vacuum system of peripheral hardware from purge column condenser overhead gas phase, acidic components, the acid for condensing out
Property component catabolite and other volatile components through purge column condenser bottom liquid phases produce, from purging tower bottom obtain acid number
Circulation solvent less than 50ppm is recycled with Returning process, so as to improve photochemical reaction efficiency to reduce life during photochemical reaction
Into accessory substance.
2. the acid number for heavy solvent method TDI products according to claim 1 reduces device, it is characterised in that the charging
Preheater, product tower condenser, reboiler and purge column condenser are the conventional components in this area, related products tower and
Purge column uses packed tower of the prior art or plate column, and its internal upper and lower ends carries distribution apparatus；The kettle being related to
Liquid pump is pneumatic diaphragm pump.
3. the acid number for heavy solvent method TDI products according to claim 2 reduces device, it is characterised in that step (1)
The photochemical reaction material that middle heavy solvent method prepares TDI contains TDI, heavy solvent M-phthalic acid diethyl for 30~100ppm of acid number
The material of ester, acidic components and other impurities, and it is stripped of hydrogen chloride, phosgene and residue component.
4. the acid number for heavy solvent method TDI products according to claim 2 reduces device, it is characterised in that what is be related to is lazy
Property gas be nitrogen, carbon dioxide or hydrogen chloride, its pressure be 1~10bar, with heavy solvent dimethyl isophthalate mole
Than being 0.5~5.
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| CN201510932871.1A CN105503655B (en) | 2015-12-14 | 2015-12-14 | A kind of acid number reduction device for heavy solvent method TDI products |
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| CN114380714B (en) * | 2020-10-16 | 2023-08-11 | 万华化学集团股份有限公司 | Circulating solvent in phosgenation production and impurity removing method thereof |
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|---|---|---|---|---|
| US4289589A (en) * | 1979-04-19 | 1981-09-15 | Basf Aktiengesellschaft | Separating toluene diisocyanate and/or higher boiling solvents from distillation residues of the toluene diisocyanate manufacture using a fluidized bed |
| CN101698652A (en) * | 2009-11-05 | 2010-04-28 | 甘肃银达化工有限公司 | Method for purifying cyclic solvent in producing TDI |
| CN101717335A (en) * | 2009-12-10 | 2010-06-02 | 甘肃银达化工有限公司 | Method for recovering DEIP in TDI residues |
| CN101870666A (en) * | 2010-05-23 | 2010-10-27 | 青岛科技大学 | Refining and reclaiming technology of tail gas absorption solvent in production of toluene diisocyanate |
-
2015
- 2015-12-14 CN CN201510932871.1A patent/CN105503655B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4289589A (en) * | 1979-04-19 | 1981-09-15 | Basf Aktiengesellschaft | Separating toluene diisocyanate and/or higher boiling solvents from distillation residues of the toluene diisocyanate manufacture using a fluidized bed |
| CN101698652A (en) * | 2009-11-05 | 2010-04-28 | 甘肃银达化工有限公司 | Method for purifying cyclic solvent in producing TDI |
| CN101717335A (en) * | 2009-12-10 | 2010-06-02 | 甘肃银达化工有限公司 | Method for recovering DEIP in TDI residues |
| CN101870666A (en) * | 2010-05-23 | 2010-10-27 | 青岛科技大学 | Refining and reclaiming technology of tail gas absorption solvent in production of toluene diisocyanate |
Non-Patent Citations (2)
| Title |
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| "TDI/DEIP分离塔的优化设计";毕荣山等;《计算机与应用化学》;20060128;第23卷(第1期);第29-32页 * |
| "甲苯二异氰酸酯精制塔的扩产优化改造";毕荣山等;《化工进展》;20071231;第26卷(第7期);第1049-1052 * |
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