CN102092713A - Method for continuously preparing phosgene - Google Patents
Method for continuously preparing phosgene Download PDFInfo
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- CN102092713A CN102092713A CN201010584341XA CN201010584341A CN102092713A CN 102092713 A CN102092713 A CN 102092713A CN 201010584341X A CN201010584341X A CN 201010584341XA CN 201010584341 A CN201010584341 A CN 201010584341A CN 102092713 A CN102092713 A CN 102092713A
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Abstract
The invention relates to a method for producing phosgene through the reaction of chlorine and carbon monoxide, and in particular to a method that chlorine and carbon monoxide are used to perform an exothermic reaction in a tube reactor in the presence of an activated carbon catalyst and generate phosgene. In the method provided by the invention, after chlorine is mixed with excess carbon monoxide in a mixer M1, then the mixture enters a tubular reactor C1 to react under the action of the activated carbon catalyst and generate phosgene and then passes through a protection reactor C2 to ensure that chlorine reacts completely; and the heat generated by the reaction is led out by a 60 DEG C cooling water system in closed cycle, the generated gaseous phosgene is cooled through W1 condensation and W2 condensation and enters a phosgene gas-liquid separation tank B2, the un-condensed gas enters an exhaust gas absorber K1, and -5 DEG C toluene is used to absorb and recycle phosgene in tail gas.
Description
Technical field
The present invention relates to a kind of method of producing phosgene, be specifically related in the presence of activated carbon catalyst, make chlorine and carbon monoxide in the shell reactor, to produce the method for phosgene by thermopositive reaction by chlorine and reaction of carbon monoxide.Wherein chlorine enters shell and tube reactor C1 with after excessive carbon monoxide mixes in mixing tank M1, and reaction generates phosgene under the activated carbon catalyst effect, again through guard reactor C2, guarantees that chlorine reaction is complete; The heat that reaction generates is derived by 60 ℃ of cooling water systems of closed cycle, the gaseous phosgene that generates is after W1, W2 condensed in two stages, cooling, enter phosgene gas-liquid separation groove B2, uncooled gas enters tail gas absorber K1, absorbs phosgene contained in the tail gas and reclaims use with-5 ℃ toluene.
Background technology
Tolylene diisocyanate (TDI) is one of isocyanic ester series products of consumption maximum in the world, is one of main raw material of urethane.The TDI production technique mainly is that the chlorine reaction that the carbon monoxide that provided by gas sweetening and chlor-alkali device provide generates phosgene (COCL
2), again by tolylene diamine (TDA) and COCL
2Reaction generates TDI, unit such as master operation has that phosgene is synthetic, TDA is synthetic, the synthetic TDI of phosgenation and rectifying, phosgene recovery, solvent recuperation, waste gas destruction.The major company of a few family that at present produces TDI in the world all uses the proprietary technology of oneself, and all uses traditional phosgenation without exception.These companies are that press in Bayer (BAYER), BASF (BASF), Dow Chemical (DOWS CHEM), rhone-poulenc (RHONE POULENE), ENI chemistry (ENI CHEM), Olympic (OLIN) and Mitsui east.Traditional phosgenation is even with phosgene and the reaction of the tolylene diamine in inert solvent, generate TDI and also emit HCL gas.Phosgenation reaction carries out in tower or in the reactor mostly.In traditional phosgene recovery system, material enters the toluene absorption tower, and phosgene is absorbed by toluene, and non-condensable gases such as HCL are discharged from cat head.
Producing phosgene by chlorine and reaction of carbon monoxide in the presence of C catalyst is a kind of well-known technology.Catalyzer wears out along with the carrying out of reaction and require to improve operating temperature all the time in time course, this point has counter productive to the composition of product gas conversely: phosgene decomposes the backward reaction that produces chlorine and carbon monoxide significantly to be increased, and this requires elapsed time to be used for gas scrubbing again; Activated-carbon catalyst itself also can cause side reaction, at high temperature, the formation of chlorine relative contact for a long time with activated carbon surface initiation tetracol phenixin, tetracol phenixin is a kind of deleterious byproduct that has a strong impact on polycarbonate output, in addition, tetracol phenixin is considered to relevant with ozone layer depletion and Global warming always.The phosgene that is come out by this explained hereafter can contain the tetracol phenixin of 400～500ppm weight usually, and by the about 4,500,000 tons of calculating of whole world phosgene production total amount, this content is equivalent to produce about 1800～2300 tons tetracol phenixin simultaneously with phosgene.Therefore, developing the amount that can make tetracol phenixin impurity, to reduce to minimum phosgene production technology be very important.A target that is prepared phosgene by chlorine and carbon monoxide is to design a kind of method that allows single step reaction, can in a wide region, change the pressure and temperature parameter of reaction, can realize the maximum flexibility in the control process thus and reduce the interference by product, as tetracol phenixin.
This strong reaction heat release in the presence of activated carbon catalyst of carbon monoxide and chlorine, its Enthalpies of Formation is-107.6kJ.Reaction is generally carried out in shell and tube-type reactor.In this course, the pelleted catalyst of granularity between the 3～5mm internal diameter of packing into is in the reaction tubes of 50～70mm.Be reflected under 40～50 ℃ of temperature and begin, temperature rises to about 400 ℃ and descends rapidly then in the pipe.Carbon monoxide is excessive in a little to guarantee all chlorine participation reactions and to obtain not chloride phosgene.Reaction can or be generally under 2～3 high pressure that cling at normal pressure to be carried out, so that phosgene can be by means of water quench.Shift out in order to improve the heat of reaction of carrying out by means of round-robin heat-transfer medium between the catalyst tube, mounting guiding board between catalyst tube is to produce the transverse flow of heat-transfer medium between catalyst tube.The known shell and tube-type reactor that is used for preparing phosgene has been covered with pipe reaching the maximum utilization of reactor inner space, and has flow deflector between catalyst tube.These plates are shorter relatively, and in the water conservancy diversion zone, heat-transfer medium becomes vertically mobile around catalyst tube from transverse flow.Catalyst tube is cooling not, causes on the catalyst tube in water conservancy diversion zone etching problem to occur.With many heats that tube reaction produced of activated-carbon catalyst in the safe dissipation shell and tube-type reactor of direct cooling, but also mentioned transpiration cooling in the document.But the gas temperature that proposes reactor exit simultaneously must be lower than 100 ℃, just can make the cl content in the phosgene be lower than 50ppm.Therefore, the method for this invention also divides two stages to carry out.In the fs of this method, at high temperature make phosgene, carry out transpiration cooling with a kind of high boiling point refrigerant, the subordinate phase of this method is carried out under 70～100 ℃ direct cooling conditions.This reactor is special tubular structure, in order to prevent corrosion, makes reactor tube with stainless steel especially.If water by in the reaction tubes because the hole that forms of corrosion enters reaction compartment, then water can with phosgene vigorous reaction on activated-carbon catalyst of formation.Reaction between this water photoreactive gas can form hydrochloric acid, thereby causes further corrosion.By the dissipation of decompression water transpiration cooling realization to phosgene producing method reaction heat, this moment, the preferred pressure that adopts was lower than barometric point, and its absolute value is 1 crust.Consider that from this respect coolant circulating is a closed cycle system preferably, wherein water is evaporated, and shifts, and in another place's condensation, is recirculated to the refrigerant space then and evaporates again.In this sense, the liquid water that is in boiling state is preferably contained in the refrigerant space in the shell and tube-type reactor.Therefore, the pressure in the reaction compartment keeps greater than the pressure in the refrigerant space, if reaction tubes damages, then phosgene can enter the refrigerant space from reaction tubes, and water can not enter the reaction tubes of reactor from the refrigerant space.Monitoring device monitoring refrigerant space by suitable has determined whether that phosgene enters refrigerant spatial sign, because exist phosgene to represent that the reaction tubes of shell and tube-type reactor is damaged in the refrigerant space.Therefore, this continuous detecting can prevent any consequent damage.The phosgene that the relative quantity of CO and chlorine can make this method produce has low cl content.Preferably using with respect to cl content is excessive 2～20 (mole) %, the CO of more preferably excessive 5～12 (mole) %.Can use any gas mixer mixing chlorine and CO of being purchased, such as the orifice mixing tank, static mixer or vortex patern mixing tank can use the conventional tube shell-type exchangers of band water coolant well known by persons skilled in the art or atmospheric condenser or other condensers as heat exchanger.Can use various monitoring devices when being damaged situation, to guarantee the security of system, particularly when corrosion takes place reaction tubes.These monitoring devices should be able to stopped reaction when surpassing the predetermined trigger value, preferably by cutting off reaction-ure feeding, equipment is converted to safe condition.
The open NO. of Japanese Patent is flat-6[1994]-29129 disclose adopt a kind of with pickling and to contain total amount be the amount (for example reducing 50%) that the activatory carbon of 1.5% (weight) or the metal component that is made of transition metal, boron, aluminium and silicon still less can reduce the tetracol phenixin that is produced in the phosgene production technology.
Chinese invention patent application 03804716.0 " being used to produce the reactor and the method for phosgene " disclose a kind of carbon monoxide and chlorine in the presence of fixed bed catalyst gas-phase reaction and produce the reactor of phosgene.Reactor comprises a branch of parallel contact tube that is fixed on along reactor longitudinal extension and bottom on the base, and there is cover at the two ends of reactor.Reactor also comprises flow deflector, in the space of flow deflector between contact tube, extends perpendicular to the longitudinal direction of reactor, and does not stop up access portal on the reactor wall, and described access portal is disposed opposite to each other in the alternative mode.Be filled with fixed bed catalyst in the contact tube, the gas-phase reaction mixture is introduced by reactor one end, by cover and contact tube, is left by the reactor the other end by second cover.Liquid heat transfer medium is conducted through the space between the contact tube, and reactor is not managed in the zone of access portal.The cross section symmetry of reactor center is built, and has a plurality of districts, separate in the close mode of liquid by dividing plate between each district, thereby heat-transfer medium can not flow into another district from a district at inside reactor.A sheath that is used to hold the multistage thermopair with two or more temperature survey points is provided at least one catalyst tube, and this sheath is at the outside opening of reactor bottom.A kind of device for preparing phosgene, wherein two or more reactors in series connect, and a measurement of concetration point and/or a temperature survey point that is used for residual chlorine content is preferably mounted at the connection place of covering on following cover of last reactor and the following reactor, and second reactor has the catalyst tube than the bigger diameter of inner pipe of first reactor, particularly diameter of inner pipe is 20～110mm, is preferably 60～90mm.
Chinese invention patent application 200510093948.7 " phosgene producing method and equipment " discloses a kind of method of making phosgene, wherein chlorine and carbon monoxide react in shell and tube-type reactor under the activated-carbon catalyst existence condition, comprise many reaction tubess in this reactor and around the refrigerant space of reaction tubes, wherein, a) make the reaction tubes cooling from the outside by the transpiration-cooled refrigerant of water space, the pressure of reaction tubes is greater than the pressure in the refrigerant space when b) operating.It is characterized in that the add-on based on chlorine, the add-on of carbon monoxide reaches excessive 2～20 moles of %, and the absolute pressure in the refrigerant space is 0.1 to 0.8 crust.The steam that evaporated in the refrigerant space in a) of condensing steps once more in heat exchanger, and water of condensation is recycled to the refrigerant space, in heat exchanger, before the condensed steam, from liquid water, isolate the steam that evaporates in the refrigerant space in the step a).Heat exchanger is positioned at the shell and tube-type reactor top, and water of condensation is returned under action of gravity in the refrigerant space that flows into shell and tube-type reactor.Coolant circulating system seals.Make the equipment of phosgene by making the reaction under the activated-carbon catalyst existence condition of chlorine and carbon monoxide, comprise: a) at least one shell and tube-type reactor, it has the reaction tubes that (i) many foundation originally are arranged in parallel with each other, (ii) center on the water-cooled space of each root reaction tubes, (iii) at least one allows water enter refrigerant spatial inlet, (iv) at least one makes water and/or steam leave the outlet of refrigerant spatial, b) at least one water circulation system, it has (i) steam/water separator, and it is by (ii) being connected with the outlet of shell and tube-type reactor from the pipeline of outlet to steam/water separator delivering vapor/water; Carry and metering CO and chlorine by pipeline 1 and 2, mix then.This step can be at a special gas mixer, and such as taking place in orifice mixing tank or the nozzle mixer, gaseous mixture enters the shell and tube-type reactor by pipeline from the below then.In shell and tube-type reactor, be filled with gac in the pipe.The reaction of product phosgene takes place to form in pipe.Phosgene leaves shell and tube-type reactor by the product pipeline.For the reaction heat of phosgene producing method in the shell and tube-type reactor that dissipates, water enters the refrigerant space of shell and tube-type reactor by water-in from the below.Water in the refrigerant space seethes with excitement in shell and tube-type reactor, leaves shell and tube-type reactor by water outlet with the steam/water mixture form then, arrives the steam/water separator by pipeline.
Chinese invention patent 00806122.X " a kind of method that is prepared phosgene by chlorine and carbon monoxide " discloses the commercial run of producing phosgene, comprises two step method of a conditioned reaction parameter that reactor is linked in sequence, accurate and reaction conditions height unanimity.This method is reacted the efficient of carrying out under the situation of periodical operation and dissemination on the low side.And the change catalyzer requires higher temperature of reaction also therefore the quality of product to be had a negative impact.Chlorine can cause the formation tetracol phenixin with contacting of gac.Other catalyzer should be able to be with the synthetic phosgene of the mode scalable, that technology simply and farthest reduces by product.The present invention relates to by chlorine and carbon monoxide by be selected from the method that phosgene is produced in reaction on the catalyzer of metal halide scalablely, wherein, the reaction parameter that comprises temperature and pressure can be selected in the scope of a broad and prevent or reduce production of by-products.Method of the present invention makes when using variable reaction parameter becomes possibility from the chlorine of the different orders of magnitude and the synthetic high-quality phosgene of reaction of carbon monoxide.
The above several aspects of contrast patent the object of the present invention is to provide the method that a kind of by product is few, contain few free chlorine, tetracol phenixin, more low-cost, safer production phosgene.Wherein dissipate by sufficient heat, guarantee that the gas temperature of reactor exit is lower than 100 ℃, the cl concn in the phosgene is lower than 50ppm, guarantees operational safety simultaneously.
Summary of the invention
From gas-cleaning installation next CO and the next chlorine of chlor-alkali device, after (CO gas is excessive) enters the M1 mixing tank by a certain percentage, enter shell and tube phosgene reactor C1 from top to bottom, generate phosgene under the activated-carbon catalyst effect, low temperature, high pressure help the chemical equilibrium that phosgene generates.Catalyzed reaction is carried out at activated carbon surface, and speed of reaction depends on the uptake rate of reagent and the desorption rate of product.In general the specific absorption carbon monoxide of chlorine is easy.Newly-increased chlorine preheater B1, solve chlorine and in course of conveying, chlorine gas liquefaction occurs owing to temperature reduces, accompanies the thermal effect difference, cause the cl content that dissociates in the phosgene to exceed standard, cause generating Cl-TDI in the photochmeical reaction, thereby have a strong impact on the problem of separation circuit operating mode.For guaranteeing to react completely, behind C1, be connected in series a phosgene guard reactor C2, make in the reaction product free chlorine few.Reaction is thermopositive reaction, and the heat that reaction generates is derived by 60 ℃ of cooling water systems of closed cycle.The gaseous phosgene that generates is chilled to-10 ℃ after phosgene condenser W1, phosgene water cooler W2 condensed in two stages, cooling, most of phosgene is liquefied, and enters phosgene gas-liquid separation groove B2.Liquid phosgene force feed is to producing TDI usefulness, uncooled phosgene and excessive CO, N
2Reach the HCl gas that side reaction produces, enter tail gas absorber K1, absorb contained phosgene in the tail gas with-5 ℃ toluene, reclaim the phosgene that is absorbed, K1 tail gas send alkali lye destruction tower to decompose to destroy wherein and arranges atmosphere after the objectionable constituent.
Phosgene building-up reactions equation is:
Cl
2+CO→COCl
2+-116.7KJ/mol
The summary technical solution of the present invention is as follows:
1, a kind of continuous method for preparing phosgene is characterized in that:
A) the first step is the phosgene synthesis procedure, excessive CO and CL
2After entering the M1 mixing tank by a certain percentage; enter shell and tube phosgene reactor C1 from top to bottom, under the activated-carbon catalyst effect, generate phosgene, behind C1, be connected in series a phosgene guard reactor C2; the heat that reaction generates is derived by 60 ℃ of cooling water systems of closed cycle, comprising:
(i) start the CO compressor and carry CO, guarantee CO pressure 0.3～0.5MPa, CO pressure reduction 〉=0.02MPa, CO temperature 〉=20 ℃, CO/CL
2Ratio 1.0, CO advances the M1 valve and opens, and CO enters M1 flow 〉=130kg/h;
(ii) start CL
2Compressor is carried CL
2, guarantee CL
2Pressure 0.3～0.5MPa, CL
2Pressure reduction 〉=0.02MPa starts CL
2Preheater B1 guarantees CL
2Temperature 〉=40 ℃, CL
2Advance the M1 valve and open CL
2Enter M1 flow 〉=300kg/h;
(iii) CL
2After excessive CO enters M1 and mixes, enter shell and tube phosgene reactor C1 from top to bottom, under the activated-carbon catalyst effect, generate phosgene, temperature raises gradually;
(iv) the heat of reaction generation is derived by 60 ℃ of cooling water systems of closed cycle;
(react completely among the phosgene guard reactor C2 that v) behind C1, is connected in series, under the activated-carbon catalyst effect, generate phosgene, make no free chlorine in the reaction product phosgene;
B) second step was that phosgene condensation and tail gas absorb operation, the gaseous phosgene that generates is chilled to-10 ℃ after phosgene condenser W1, phosgene water cooler W2 condensed in two stages, cooling, most of phosgene is liquefied, enter phosgene gas-liquid separation groove B2, liquid phosgene force feed is used to producing TDI.Uncooled phosgene and excessive CO, N
2Reach the HCl gas that side reaction produces, enter tail gas absorber K1, absorb contained phosgene in the tail gas with-5 ℃ toluene, reclaim the phosgene that is absorbed, K1 tail gas send alkali lye destruction tower to decompose to destroy wherein and arranges atmosphere after the objectionable constituent.Comprise:
(i) gaseous phosgene of Sheng Chenging is through phosgene condenser W1 condensation;
After the gaseous phosgene water cooler W2 cooling that (ii) generates;
(iii) be chilled to-10 ℃, most of phosgene is liquefied, and enters phosgene gas-liquid separation groove B2;
(iv) liquid phosgene force feed is used to producing TDI.
(v) uncooled phosgene and excessive CO, N
2And the HCl gas of side reaction generation, enter tail gas absorber K1, absorb contained phosgene in the tail gas with-5 ℃ toluene.
2, method according to claim 1 is characterized in that CL
2Must be introduced into and enter again into after the chlorine preheater B1 preheating that M1 mixes with excessive CO.
3, method according to claim 1 is characterized in that control process parameters comprises: CL
2Enter M1 flow 2357～4704kg/h, 45～55 ℃ of temperature, pressure 0.3～0.5MPa, pressure reduction 0.02～0.04MPa, CO enter M1 flow 1023～2046kg/h, 20～30 ℃ of temperature, pressure 0.3～0.5MPa, pressure reduction 0.02～0.04MPa, CO/CL
2Ratio 1.0,40～50 ℃ of M200 temperature outs, 40～50 ℃ of C1 head temperature, enter warm water flow 〉=185T/h, 65～70 ℃ of C1 warm water return water temperatures, 60～70 ℃ of C1 outlet material temperature, the C2 temperature difference≤2 ℃, 60～70 ℃ of C2 temperature outs, free chlorine≤10ppm in the phosgene of C2 exit, W1 water coolant backwater pH value 8.5 has the tubulation of freezing toluene to lower the temperature around B2 in using, guarantee that phosgene is liquid phase in the B2, go out freezing toluene flux 〉=2500kg/h from B2, B2 liquid level 30～40%, B2 temperature-5～-10 ℃, enter K1 technology toluene 500～600kg/h, K1 cat head exhaust gas flow 124～180kg/h, liquid level 30～58% at the bottom of the K1 tower, K1 top pressure 0.3～0.4MPa, K1 cat head exhaust gas pressure 0.01～0.03MPa, 5～10 ℃ of K1 column bottom temperatures.
4, method according to claim 1 is characterized in that: CL
2Pressure reduction＜0.02Mpa, CL
2Advance the M1 valve closes; CL
2Flow＜300kg/h, CO advance the M1 valve closes; CO pressure reduction＜0.02Mpa, CO advance the M1 valve closes; CO flow＜130kg/h, the W2 outlet valve is closed; CO/CL
2Ratio＜0.95, the B2 outlet valve is closed.
5, method according to claim 1, the step that it is characterized in that driving comprises:
A) CO purges;
B) the warm water system drives;
C) K1 drives;
D) W1, W2, B2 drive;
E) CO feeds intake;
F) CL
2Feed intake.
6, method according to claim 1 is characterized in that shut-down operation comprises:
A) stop CL
2Feed intake;
B) CO purges;
C) N
2Purge;
D) B2 batch turning;
E) warm water system shutdown;
F) K1, W1, W2 stop;
G) system and other unit are disconnected.
7, method according to claim 4 is characterized in that key points for operation comprise:
A) should strict control CL in the production process
2Feeding temperature, pressure prevent liquefaction;
B) strict control CO, CL
2Feed ratio is guaranteed CL
2React completely.
8, method according to claim 5 is characterized in that key points for operation comprise:
A) before warm water system and the parking of W1 water coolant, C1, C2, W1 system pressure must keep 〉=0.3MPa;
B) to the equipment of need maintenance, before overhauling, the essential isolation thoroughly purges, and confirms can overhaul behind the no phosgene.
9, method according to claim 1 is characterized in that C1 catalyst loading key points for operation comprise:
A) every tubulation catalyst loading is wanted evenly;
B) every tubulation bottom should keep the high inertia district of 145mm, and the space of 30cm should be stopped in the top;
C) prevent that catalyzer from falling in the C1 lower tube.
10, method according to claim 1 is characterized in that C2 catalyst loading key points for operation are that catalyzer top should be pushed down by silk screen, prevent that catalyzer from blowing out.
Description of drawings
Accompanying drawing represents that phosgenation prepares the process flow diagram of tolylene diisocyanate.
Code name explanation: B1-Cl among the figure
2Preheater, M1-CO, Cl
2Mixing tank, C1-phosgene synthesis reactor, C2-phosgene guard reactor, W1-phosgene condenser, W2-phosgene water cooler, B2-phosgene gas-liquid separation groove, K1-tail gas absorber.
Embodiment
The following example is used to further describe the inventive method.Above disclosed the spirit and scope of the present invention be not subjected to the restriction of these embodiment.
Embodiment one
Reactor, tower process condition are controlled as following table:
Embodiment two
Reactor, tower process condition are controlled as following table:
Although in above illustrating, describe the present invention in detail, should be understood that described details only is used to illustrate, those skilled in the art can make change to it in not deviating from the spirit and scope that claim of the present invention limits.
Claims (9)
1. method for preparing continuously phosgene is characterized in that:
A) the first step is the phosgene synthesis procedure, excessive CO and CL
2After entering the M1 mixing tank by a certain percentage; enter shell and tube phosgene reactor C1 from top to bottom, under the activated-carbon catalyst effect, generate phosgene, behind C1, be connected in series a phosgene guard reactor C2; the heat that reaction generates is derived by 60 ℃ of cooling water systems of closed cycle, comprising:
(i) start the CO compressor and carry CO, guarantee CO pressure 0.3～0.5MPa, CO pressure reduction 〉=0.02MPa, CO temperature 〉=20 ℃, CO/CL
2Ratio 1.0, CO advances the M1 valve and opens, and CO enters M1 flow 〉=130kg/h; (ii) start CL
2Compressor is carried CL
2, guarantee CL
2Pressure 0.3～0.5MPa, CL
2Pressure reduction 〉=0.02MPa starts CL
2Preheater B1 guarantees CL
2Temperature 〉=40 ℃, CL
2Advance the M1 valve and open CL
2Enter M1 flow 〉=300kg/h;
(iii) CL
2After excessive CO enters M1 and mixes, enter shell and tube phosgene reactor C1 from top to bottom, under the activated-carbon catalyst effect, generate phosgene, temperature raises gradually;
(iv) the heat of reaction generation is derived by 60 ℃ of cooling water systems of closed cycle;
(react completely among the phosgene guard reactor C2 that v) behind C1, is connected in series, under the activated-carbon catalyst effect, generate phosgene, make little free chlorine in the reaction product phosgene;
B) second step was that phosgene condensation and tail gas absorb operation, the gaseous phosgene that generates is after phosgene condenser W1, phosgene water cooler W2 condensed in two stages, cooling, be chilled to-10 ℃, most of phosgene is liquefied, enter phosgene gas-liquid separation groove B2, liquid phosgene force feed is to producing TDI usefulness, uncooled phosgene and excessive CO, N
2Reach the HCl gas that side reaction produces, enter tail gas absorber K1, absorb contained phosgene in the tail gas with-5 ℃ toluene, reclaim the phosgene that is absorbed, K1 tail gas send alkali lye destruction tower to decompose to destroy wherein and arranges atmosphere after the objectionable constituent.Comprise:
(i) gaseous phosgene of Sheng Chenging is through phosgene condenser W1 condensation;
After the gaseous phosgene phosgene water cooler W2 cooling that (ii) generates;
(iii) be chilled to-10 ℃, most of phosgene is liquefied, and enters phosgene gas-liquid separation groove B2;
(iv) liquid phosgene force feed is used to producing TDI;
(v) uncooled phosgene and excessive CO, N
2And the HCl gas of side reaction generation, enter tail gas absorber K1, absorb contained phosgene in the tail gas with-5 ℃ toluene.
2. method according to claim 1 is characterized in that control process parameters comprises: CL
2Enter M1 flow 2357～4704kg/h, 45～55 ℃ of temperature, pressure 0.3～0.5MPa, pressure reduction 0.02～0.04MPa, CO enter M1 flow 1023～2046kg/h, 20～30 ℃ of temperature, pressure 0.3～0.5MPa, pressure reduction 0.02～0.04MPa, CO/CL
2Ratio 1.0,40～50 ℃ of M200 temperature outs, 40～50 ℃ of C1 head temperature, enter warm water flow 〉=185T/h, 65～70 ℃ of C1 warm water return water temperatures, 60～70 ℃ of C1 outlet material temperature, the C2 temperature difference≤2 ℃, 60～70 ℃ of C2 temperature outs, free chlorine≤10ppm in the phosgene of C2 exit, W1 water coolant backwater pH value 8.5 has the tubulation of freezing toluene to lower the temperature around B2 in using, guarantee that phosgene is liquid phase in the B2, go out freezing toluene flux 〉=2500kg/h from B2, B2 liquid level 30～40%, B2 temperature-5～-10 ℃, enter K1 technology toluene 500～600kg/h, K1 cat head exhaust gas flow 124～180kg/h, liquid level 30～58% at the bottom of the K1 tower, K1 top pressure 0.3～0.4MPa, K1 cat head exhaust gas pressure 0.01～0.03MPa, 5～10 ℃ of K1 column bottom temperatures.
3. method according to claim 1 is characterized in that: CL
2Pressure reduction＜0.02Mpa, CL
2Advance the M1 valve closes; CL
2Flow＜300kg/h, CO advance the M1 valve closes; CO pressure reduction＜0.02Mpa, CO advance the M1 valve closes; CO flow＜130kg/h, the W2 outlet valve is closed; CO/CL
2Ratio＜0.95, the B2 outlet valve is closed.
4. method according to claim 1, the step that it is characterized in that driving comprises:
A) CO purges;
B) the warm water system drives;
C) K1 drives;
D) W1, W2, B2 drive;
E) CO feeds intake;
F) CL
2Feed intake.
5. method according to claim 1 is characterized in that shut-down operation comprises:
A) stop CL
2Feed intake;
B) CO purges;
C) N
2Purge;
D) B2 batch turning;
E) warm water system shutdown;
F) K1, W1, W2 stop;
G) system and other unit are disconnected.
6. method according to claim 4 is characterized in that key points for operation comprise:
A) should strict control CL in the production process
2Feeding temperature, pressure, prevent liquefaction;
B) strict control CO, CL
2Feed ratio is guaranteed CL
2React completely.
7. method according to claim 5 is characterized in that key points for operation comprise:
A) before warm water system and the parking of W1 water coolant, C1, C2, W1 system pressure must keep 〉=0.3MPa;
B) to the equipment of need maintenance, before overhauling, the essential isolation thoroughly purges, and confirms can overhaul behind the no phosgene.
8. method according to claim 1 is characterized in that C1 catalyst loading key points for operation comprise:
A) every tubulation catalyst loading is wanted evenly;
B) every tubulation bottom should keep the high inertia district of 145mm, and the space of 30cm should be stopped in the top;
C) prevent that catalyzer from falling in the C1 lower tube.
9. method according to claim 1 is characterized in that C2 catalyst loading key points for operation are that catalyzer top should be pushed down by silk screen, prevent that catalyzer from blowing out.
Priority Applications (1)
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| CN103570018A (en) * | 2013-10-29 | 2014-02-12 | 嘉兴学院 | Safe phosgene preparation method and device |
| CN104492237A (en) * | 2014-12-28 | 2015-04-08 | 甘肃银光聚银化工有限公司 | Recovery method of phosgene synthesis tail gas |
| CN105197931A (en) * | 2014-11-10 | 2015-12-30 | 青岛科技大学 | Low-consumption environment-friendly efficient phosgene synthesis technology |
| CN105384640A (en) * | 2015-10-26 | 2016-03-09 | 安徽广信农化股份有限公司 | Exhaust gas treatment process for paranitrobenzoyl chloride |
| CN105817183A (en) * | 2015-01-07 | 2016-08-03 | 万华化学集团股份有限公司 | Method for replacing phosgene synthetic tower catalyst |
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| CN107617393A (en) * | 2017-09-18 | 2018-01-23 | 徐州工程学院 | A kind of phosgene reactor for carbon tetrachloride processing equipment |
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| CN109794147A (en) * | 2019-03-20 | 2019-05-24 | 金川集团股份有限公司 | A kind of row pressure chlorine gas safe recycling and processing device |
| CN109956459A (en) * | 2017-12-22 | 2019-07-02 | 中化近代环保化工(西安)有限公司 | A kind of method of industrialized production carbonyl fluoride |
| CN110655079A (en) * | 2019-09-24 | 2020-01-07 | 万华化学（宁波）有限公司 | Method for preparing phosgene |
| CN111051277A (en) * | 2017-09-06 | 2020-04-21 | 科思创德国股份有限公司 | Method for cleaning a facility with phosgene |
| CN111995549A (en) * | 2020-09-03 | 2020-11-27 | 万华化学集团股份有限公司 | Method for producing MDI and phosgene |
| CN113402383A (en) * | 2020-03-17 | 2021-09-17 | 上海祖玥新材料科技有限公司 | Method for synthesizing 2-ethylcaproic acid chloride by reacting 2-ethylhexanoic acid with phosgene |
| CN114146652A (en) * | 2021-12-06 | 2022-03-08 | 甘肃银光聚银化工有限公司 | Phosgene synthesis reaction waste gas recycling method |
| CN114920668A (en) * | 2022-05-13 | 2022-08-19 | 万华化学集团股份有限公司 | Method for preparing isocyanate with low chlorinated impurity |
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| CN103570018A (en) * | 2013-10-29 | 2014-02-12 | 嘉兴学院 | Safe phosgene preparation method and device |
| CN105197931A (en) * | 2014-11-10 | 2015-12-30 | 青岛科技大学 | Low-consumption environment-friendly efficient phosgene synthesis technology |
| CN104492237A (en) * | 2014-12-28 | 2015-04-08 | 甘肃银光聚银化工有限公司 | Recovery method of phosgene synthesis tail gas |
| CN105817183B (en) * | 2015-01-07 | 2018-04-13 | 万华化学集团股份有限公司 | A kind of method of optical self-encoding tower catalyst change |
| CN105817183A (en) * | 2015-01-07 | 2016-08-03 | 万华化学集团股份有限公司 | Method for replacing phosgene synthetic tower catalyst |
| CN105384640A (en) * | 2015-10-26 | 2016-03-09 | 安徽广信农化股份有限公司 | Exhaust gas treatment process for paranitrobenzoyl chloride |
| CN107314918A (en) * | 2016-04-26 | 2017-11-03 | 中国石油化工股份有限公司 | Sampling apparatus and the method sampled using it |
| CN106748794A (en) * | 2017-01-12 | 2017-05-31 | 山东德普化工科技有限公司 | A kind of two（Trichloromethyl）The synthesizer and method of carbonic ester |
| CN106748794B (en) * | 2017-01-12 | 2020-04-21 | 山东德普化工科技有限公司 | Synthesis device and method of bis (trichloromethyl) carbonate |
| CN111051277A (en) * | 2017-09-06 | 2020-04-21 | 科思创德国股份有限公司 | Method for cleaning a facility with phosgene |
| CN111051277B (en) * | 2017-09-06 | 2022-09-09 | 科思创德国股份有限公司 | Method for cleaning a facility with phosgene |
| CN107617393A (en) * | 2017-09-18 | 2018-01-23 | 徐州工程学院 | A kind of phosgene reactor for carbon tetrachloride processing equipment |
| CN109956459A (en) * | 2017-12-22 | 2019-07-02 | 中化近代环保化工(西安)有限公司 | A kind of method of industrialized production carbonyl fluoride |
| CN109289714A (en) * | 2018-10-30 | 2019-02-01 | 甘肃银光聚银化工有限公司 | A kind of packing method of optical self-encoding catalysts |
| CN109794147A (en) * | 2019-03-20 | 2019-05-24 | 金川集团股份有限公司 | A kind of row pressure chlorine gas safe recycling and processing device |
| CN110655079A (en) * | 2019-09-24 | 2020-01-07 | 万华化学（宁波）有限公司 | Method for preparing phosgene |
| CN110655079B (en) * | 2019-09-24 | 2023-03-03 | 万华化学（宁波）有限公司 | Method for preparing phosgene |
| CN113402383A (en) * | 2020-03-17 | 2021-09-17 | 上海祖玥新材料科技有限公司 | Method for synthesizing 2-ethylcaproic acid chloride by reacting 2-ethylhexanoic acid with phosgene |
| CN111995549A (en) * | 2020-09-03 | 2020-11-27 | 万华化学集团股份有限公司 | Method for producing MDI and phosgene |
| CN111995549B (en) * | 2020-09-03 | 2023-01-13 | 万华化学集团股份有限公司 | Method for producing MDI and phosgene |
| CN114146652A (en) * | 2021-12-06 | 2022-03-08 | 甘肃银光聚银化工有限公司 | Phosgene synthesis reaction waste gas recycling method |
| CN114920668A (en) * | 2022-05-13 | 2022-08-19 | 万华化学集团股份有限公司 | Method for preparing isocyanate with low chlorinated impurity |
| CN114920668B (en) * | 2022-05-13 | 2023-10-13 | 万华化学集团股份有限公司 | Method for preparing low-chlorine impurity isocyanate |
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