A kind of light naphtha is produced the process unit of tolylene diisocyanate
Technical field
The utility model relates to the production of toluene diisocyanate apparatus field, and specifically a kind of light naphtha is produced the process unit of tolylene diisocyanate.
Background technology
The process unit of the existing light naphtha method production TDI of China (tolylene diisocyanate) is roughly as follows at present: contain a large amount of light naphtha (orthodichlorobenzenes, chlorobenzene etc.) excess phosgene prepares TDI with the light naphtha solution that contains MTD continuous light gasification reaction in the actinic reactor reaction, reaction product enters the Reaction Separation device then, the isolated gas phase of cat head is gone into phosgene absorbing tower through photochmeical reaction water cooler cooling is laggard, isolate highly purified hydrogen chloride gas through the cat head after 0.5MPa (G) absorbs down of the light naphtha about-10 ℃, then be the phosgene solution that contains about 40% at the bottom of the tower, mix with fresh phosgene through pump pressurization back and send the actinic reactor participation to react.A liquid phase part is returned the Reaction Separation device at the bottom of the Reaction Separation device tower after the reboiler heating, another part then removes tower photoreactive gas normal pressure through the phosgene malleation successively and removes and send TDI distillation system after tower removes the residue phosgene that wherein contains and hydrogen chloride gas, removes the phosgene and the hydrogenchloride that come and be back to the photochmeical reaction water cooler after the firsts and seconds compressor boosts.
In the whole process in order to realize separating of phosgene and hydrogenchloride, used a large amount of low temperature light naphthas that phosgene is absorbed, mother liquor phosgene concentration after the absorption is about 40%, and hydrogen cloride concentration is about 2.5%, and mother liquor is light echo reactor and the reaction of two amido toluene after pump boosts.Because photochmeical reaction is an acutely reaction fast, wherein the size of phosgene concentration and hydrogen cloride concentration is very big to the influential effect of photochmeical reaction.Phosgene concentration is high more, and side reaction is just few more; The existence of hydrogenchloride can increase the generation of side reaction, reduces reaction yield.Because the existence of a large amount of solvents has reduced the phosgene concentration that participates in reaction, the while is because the existence of hydrogenchloride is all unfavorable to the separation of reaction and follow-up solvent in this flow process.Simultaneously, owing to the type selecting of the feasible relevant pump of the reason of a large amount of solvents, tower, interchanger and connecting tube etc. is bigger, facility investment and process cost are all higher, and the capacity expansion revamping of process unit also has been subjected to great restriction.
Summary of the invention
Technical assignment of the present utility model is at above weak point, provides that a kind of reaction yield height, production cost are low, a kind of light naphtha of long service life, less energy consumption produces the process unit of tolylene diisocyanate.
The technical scheme that its technical problem that solves the utility model adopts is: this process unit comprises that Reaction Separation device, phosgene malleation remove tower, the phosgene normal pressure removes tower, phosgene absorbing tower, phosgene desorption tower, salt acid tower and mixing reactor, mixing reactor by pipeline remove tower with Reaction Separation device, phosgene malleation respectively, the phosgene normal pressure removes tower and the phosgene desorption tower is communicated with; The Reaction Separation device removes tower and phosgene normal pressure with phosgene absorbing tower, phosgene malleation respectively by pipeline and removes tower and be communicated with; The phosgene malleation removes tower and phosgene normal pressure and removes tower and pass through pipeline connection; Phosgene absorbing tower is communicated with the phosgene desorption tower by pipeline; The phosgene desorption tower is communicated with the salt acid tower by pipeline.
The intake line of described mixing reactor is provided with interchanger and mixing tank.
The cat head delivery conduit of described Reaction Separation device is provided with the photochmeical reaction water cooler, and delivery conduit is provided with the photochmeical reaction recycle pump at the bottom of the tower of Reaction Separation device, and the intake line of Reaction Separation device is provided with reboiler.
The cat head delivery conduit that described phosgene malleation removes tower is provided with the phosgene malleation and removes tower condenser, a stage compressor, two stage compressor and condensate pump, the phosgene malleation removes at the bottom of the tower of tower delivery conduit and is provided with the phosgene malleation and removes the tower recycle pump, and the intake line that the phosgene malleation removes tower is provided with the phosgene malleation and removes the tower reboiler.
The tower bottom tube road that described phosgene normal pressure removes tower is provided with the phosgene normal pressure and removes tower reboiler photoreactive gas normal pressure and remove the tower recycle pump.
The cat head delivery conduit of described phosgene absorbing tower is provided with vent condenser and tail gas separator; Delivery conduit is provided with absorption tower recycle pump and absorption tower reboiler at the bottom of the tower of phosgene absorbing tower; The intake line of phosgene absorbing tower is provided with solvent cooler, and the tower lateral line of phosgene absorbing tower is provided with at least one side cooler.
The cat head delivery conduit of described phosgene desorption tower is provided with cat head secondary condenser, cat head first-stage condenser photoreactive gas pump, and delivery conduit is provided with recycle pump at the bottom of preheater one and the tower at the bottom of the tower of phosgene desorption tower; The intake line of phosgene desorption tower is provided with water cooler and preheater two.
The tower bottom tube road of described salt acid tower is provided with hydrochloric acid tower cooler device and salt acid tower recycle pump.
The process unit that a kind of light naphtha of the present utility model is produced tolylene diisocyanate is compared with prior art, has following characteristics:
1) by after the improvement to process unit, the phosgene logistics of participating in photochmeical reaction substantially no longer contains solvent and hydrogenchloride, has reduced the generation of side reaction, makes the reaction yield of same reactor improve about 5%.
2) reduce the obstruction frequency of reactor, reduced the maintenance number of times, prolonged the operating time of device.
3) owing to round-robin quantity of solvent in the system reduces significantly, the size and the capacity of used pump, compressor, tower, interchanger and pipeline reduce thereupon, and energy consumptions such as power consumption, steam and recirculated water also reduce significantly, have saved process cost and investment cost.
Description of drawings
Below in conjunction with accompanying drawing the utility model is further specified.
Accompanying drawing is the structural representation that light naphtha is produced the process unit of tolylene diisocyanate.
Among the figure: 1, the Reaction Separation device, 2, the phosgene malleation removes tower, and 3, the phosgene normal pressure removes tower, 4, phosgene absorbing tower, 5, the phosgene desorption tower, 6, the salt acid tower, 7, mixing reactor, 8, interchanger, 9, mixing tank, 10, the photochmeical reaction water cooler, 11, two stage compressor, 12, one stage compressor, 13, the phosgene malleation removes tower condenser, 14, the photochmeical reaction recycle pump, 15, reboiler, 16, condensate pump, 17, the phosgene malleation removes tower recycle pump, 18, the phosgene malleation removes the tower reboiler, 19, the phosgene normal pressure removes tower reboiler, 20, the phosgene normal pressure removes tower recycle pump, 21, vent condenser, 22, the tail gas separator, 23, side cooler, 24, the absorption tower recycle pump, 25, the absorption tower reboiler, 26, the cat head secondary condenser, 27, the cat head first-stage condenser, 28, the phosgene pump, 29, preheater one, 30, water cooler, 31, recycle pump at the bottom of the tower, 32, preheater two, 33, solvent cooler, 34, hydrochloric acid tower cooler device, 35, salt acid tower recycle pump.
Embodiment
The utility model is described in further detail below in conjunction with the drawings and specific embodiments.
A kind of light naphtha of the present utility model is produced the process unit of tolylene diisocyanate, this process unit comprises that Reaction Separation device 1, phosgene malleation remove tower 2, the phosgene normal pressure removes tower 3, phosgene absorbing tower 4, phosgene desorption tower 5, salt acid tower 6 and mixing reactor 7, mixing reactor 7 by pipeline remove tower 2 with Reaction Separation device 1, phosgene malleation respectively, the phosgene normal pressure removes tower 3 and phosgene desorption tower 5 is communicated with; Reaction Separation device 1 removes tower 2 and phosgene normal pressure with phosgene absorbing tower 4, phosgene malleation respectively by pipeline and removes tower 3 and be communicated with; The phosgene malleation removes tower 2 and removes tower 3 with the phosgene normal pressure and pass through pipeline connection; Phosgene absorbing tower 4 is communicated with phosgene desorption tower 5 by pipeline; Phosgene desorption tower 5 is communicated with salt acid tower 6 by pipeline.
The intake line of mixing reactor 7 is provided with interchanger 8 and mixing tank 9; The cat head delivery conduit of Reaction Separation device 1 is provided with photochmeical reaction water cooler 10, and delivery conduit is provided with photochmeical reaction recycle pump 14 at the bottom of the tower of Reaction Separation device 1, and the intake line of Reaction Separation device 1 is provided with reboiler 15; The cat head delivery conduit that the phosgene malleation removes tower 2 is provided with the phosgene malleation and removes tower condenser 13, a stage compressor 12, two stage compressor 11 and condensate pump 16, the phosgene malleation removes at the bottom of the tower of tower 2 delivery conduit and is provided with the phosgene malleation and removes tower recycle pump 17, and the intake line that the phosgene malleation removes tower 2 is provided with the phosgene malleation and removes tower reboiler 18; The tower bottom tube road that the phosgene normal pressure removes tower 3 is provided with the phosgene normal pressure and removes tower reboiler 19 photoreactive gas normal pressures and remove tower recycle pump 20; The cat head delivery conduit of phosgene absorbing tower 4 is provided with vent condenser 21 and tail gas separator 22; Delivery conduit is provided with absorption tower recycle pump 24 and absorption tower reboiler 25 at the bottom of the tower of phosgene absorbing tower 4; The intake line of phosgene absorbing tower 4 is provided with solvent cooler 33, and the tower lateral line of phosgene absorbing tower 4 is provided with 1-5 side cooler 23; The cat head delivery conduit of phosgene desorption tower 5 is provided with cat head secondary condenser 26, cat head first-stage condenser 27 photoreactive gas pumps 28, and delivery conduit is provided with recycle pump 31 at the bottom of preheater 1 and the tower at the bottom of the tower of phosgene desorption tower 5; The intake line of phosgene desorption tower 5 is provided with water cooler 30 and preheater 2 32; The tower bottom tube road of salt acid tower 6 is provided with hydrochloric acid tower cooler device 34 and salt acid tower recycle pump 35.
Technological process is: isolate most phosgene and hydrogenchloride through Reaction Separation device 1 after excess phosgene and the tolylene diamine reaction, the cat head gas phase then is cooled to 40 ℃ through photochmeical reaction water cooler 10 and send phosgene absorbing tower 4, liquid phase then removes tower 2 photoreactive gas normal pressures through the phosgene malleation successively and removes tower 3 at the bottom of the tower, two tops of tower are isolated remaining phosgene and hydrogenchloride, and remove tower condenser 13 through the phosgene malleation and be condensed to-4 ℃, liquid phase mainly is phosgene and trace solvent, send mixing reactor 7 after condensate pump 16 boosts, gas phase then boosts to 0.6MPa (G) through a stage compressor 12 and two stage compressor 11 and send photochmeical reaction water cooler 10.The phosgene normal pressure mainly is thick TDI and solvent at the bottom of removing the tower of tower 3, and 185 ℃ of temperature are sent TDI refining system.
A large amount of phosgene and hydrogenchloride enter phosgene absorbing tower 4, low-temperature solvent with about-10 ℃ under 0.5MPa (G) absorbs, the cat head of phosgene absorbing tower 4 is isolated about 98.5 (wt) % hydrogen chloride gas, deliver to the hydrochloric acid absorption unit, about 117 ℃ of phosgene solutions send phosgene desorption tower 5 at the bottom of the tower of phosgene absorbing tower 4.Phosgene desorption tower 5 is a packing tower, and cat head and column bottom temperature are respectively 40 ℃ and 181 ℃.Adopting middle pressure steam (1.8MPa (G)) at the bottom of the tower is that thermal source, solvent are that steam stripping agent carries out the desorb separation to phosgene solution under normal pressure, the highly purified light naphtha of extraction at the bottom of the tower, 181 ℃ of temperature for making full use of the heat of this burst logistics, are sent the solvent storage tank after making itself and the 5 charging heat exchange of phosgene desorption tower.Obtain high purity liquid phase phosgene after the cat head gas phase is condensed to-10 ℃ and after phosgene pump 28 boosts, send mixing reactor 7, non-condensable gas mainly contains hydrogenchloride and a little of phosgene, under normal pressure, be absorbed as hydrochloric acid through de-salted water, salt acid tower 6 also is a packing tower, and cat head and column bottom temperature are respectively 40 ℃ and 70.5 ℃.