Summary of the invention
For Problems existing in correlation technique, the object of the present invention is to provide a kind of vinyl cyanide system for separating and purifying, at least to realize the refining yield improving acrylonitrile process.
For achieving the above object, the invention provides a kind of vinyl cyanide system for separating and purifying, comprising: quench tower, be communicated with pipeline section with its tower top sidewall by first at the bottom of the tower of quench tower and be connected; Knockout tower, the material inlet of knockout tower is communicated with pipeline section and is communicated with pipeline section by second and is communicated with first, the gaseous phase materials on its top exports and is communicated with quench tower; And sulphuric acid soln transfer lime, transfer lime is communicated with quench tower.
According to the present invention, sulphuric acid soln transfer lime and first is communicated with pipeline section and is connected, be communicated with quench tower to be communicated with pipeline section by first, wherein, along first be communicated with pipeline section from the bottom of quench tower tower to the direction of its tower top sidewall, transfer lime and first is communicated with the first link position that pipeline section is connected, and is positioned at the downstream that the second connection pipeline section and first is communicated with the second link position that pipeline section is connected.
According to the present invention, also comprise reboiler and steam manifold, wherein, reboiler is connected with knockout tower, and steam manifold has the first branch road and the second branch road, and the first branch road is connected to reboiler, second branch road is connected to knockout tower, wherein, by being arranged on the shifter in steam manifold, the steam controlled in steam manifold enters the first branch road or the second branch road.
According to the present invention, bunch grade adjustment device is connected with between knockout tower and steam manifold, bunch grade adjustment device comprises temperature monitor, flow monitor and variable valve, wherein, the tower top temperature of temperature monitor to knockout tower is monitored, and controls according to monitor value the aperture that flow monitor regulates variable valve.
According to the present invention, level monitoring device is connected with at the bottom of the tower of quench tower and between the second connection pipeline section, wherein, level monitoring device, according to the liquid level of reaction mass in quench tower, controls to be communicated with pipeline section by first and flows into the flow that second is communicated with the intermediate reaction product of pipeline section.
According to the present invention, sulphuric acid soln transfer lime is communicated with between pipeline section with first and is provided with pH value monitoring device, wherein, pH value monitoring device is communicated with the link position of pipeline section with first, between the first link position and the second link position, wherein, pH value monitoring device is communicated with the pH value of intermediate reaction product in pipeline section according to first, controls sulphuric acid soln transfer lime is communicated with pipeline section conveying sulphuric acid soln operational throughput to first.
According to the present invention, knockout tower bottom is connected with material recycle pipe, is provided with fluid level control device, wherein bottom knockout tower and between material recycle pipe, fluid level control device, according to the liquid level of reaction mass in knockout tower, controls the flow flowing into material to be recycled in material recycle pipe.
According to the present invention, the tower top of quench tower is provided with finished product product exit, and quench tower inside is provided with the first spray equipment, and wherein, the port that the first spray equipment is communicated with pipeline section with first of the tower top sidewall being communicated to quench tower is communicated with.
According to the present invention, quench tower sidewall is also provided with reaction gas entrance, and quench tower inside is also provided with the second spray equipment, and wherein, reaction gas entrance is communicated with the second spray equipment.
According to the present invention, be communicated with in pipeline section with first between the second link position at the bottom of the tower of quench tower and be in series with recycle pump.
Advantageous Effects of the present invention is:
In vinyl cyanide system for separating and purifying of the present invention, sulphuric acid soln transfer lime can carry sulphuric acid soln in quench tower, to react with the reaction gas sending into quench tower.Wherein, in reaction gas, at least comprise propylene steam nitrile and ammonia, also can include gaseous hydrogen cyanic acid, gaseous state acetonitrile etc.In quench tower, sulphuric acid soln and this reaction gas react to purify to this reaction gas.Particularly, in quench tower, sulphuric acid soln and ammonia gas react generate ammoniumsulphate soln, to be removed by the ammonia in reaction gas.Propylene steam nitrile in reaction gas moves towards the tower top of quench tower.The ammoniumsulphate soln generated after reaction flow at the bottom of the tower of quench tower, wherein, ammoniumsulphate soln can be mingled with the liquid propylene nitrile of condensation in quench tower flowing in the process at the bottom of tower, and unreacted sulphuric acid soln also flow at the bottom of the tower of quench tower, thus, the intermediate reaction product be positioned at the bottom of quench tower tower at least comprises ammoniumsulphate soln, sulphuric acid soln, liquid propylene nitrile.By accessing knockout tower at the bottom of the tower of quench tower and between tower top sidewall, secondary being carried out to the intermediate reaction product of quench tower and is separated again and required product is sent back in quench tower again.Particularly, in knockout tower, vinyl cyanide in intermediate reaction product is isolated and sends quench tower back to, so in quench tower first time purification gained propylene steam nitrile and form finished product product through the propylene steam nitrile of knockout tower secondary separation gained and discharged by quench tower.In this way, on the one hand, effectively can remove the ammonia in reaction gas, on the other hand, reduce the loss of vinyl cyanide in above-mentioned removal process.Make vinyl cyanide refine yield thus to improve, and promote the purity of propylene steam nitrile.
Embodiment
Embodiments of the invention are specifically described referring to accompanying drawing.With reference to Fig. 1, show an embodiment of vinyl cyanide system for separating and purifying of the present invention, it sulphuric acid soln transfer lime 3 comprising quench tower 1, knockout tower 2 and be communicated in quench tower 1.Wherein, be communicated with pipeline section 8 with the tower top sidewall of quench tower 1 by first at the bottom of the tower of quench tower 1 to be connected, the material inlet of knockout tower 2 is communicated with pipeline section 8 and is communicated with pipeline section 9 by second and is communicated with first, the gaseous phase materials outlet on knockout tower 2 top is communicated with by third connecting pipeline section 22 with quench tower 1.
When said system works, sulphuric acid soln transfer lime 3 can carry sulphuric acid soln in quench tower 1, to react with the reaction gas sending into quench tower 1.Wherein, in reaction gas, at least comprise propylene steam nitrile and ammonia, also can include gaseous hydrogen cyanic acid, gaseous state acetonitrile etc.In quench tower 1, sulphuric acid soln and this reaction gas react to purify to this reaction gas.Particularly, in quench tower 1, sulphuric acid soln and ammonia gas react generate ammoniumsulphate soln, to be removed by the ammonia in reaction gas.Propylene steam nitrile in reaction gas moves towards the tower top of quench tower 1.The ammoniumsulphate soln generated after reaction flow at the bottom of the tower of quench tower 1, wherein, ammoniumsulphate soln can be mingled with the liquid propylene nitrile of condensation in quench tower 1 flowing in the process at the bottom of tower, and unreacted sulphuric acid soln also flow at the bottom of the tower of quench tower 1, thus, the intermediate reaction product be positioned at the bottom of quench tower 1 tower at least comprises ammoniumsulphate soln, sulphuric acid soln, liquid propylene nitrile.By accessing knockout tower 2 at the bottom of the tower of quench tower 1 and between tower top sidewall, secondary being carried out to the intermediate reaction product of quench tower 1 and is separated again and required product is sent back in quench tower again.Particularly, in knockout tower 2, vinyl cyanide in intermediate reaction product is isolated and sends quench tower back to, so in quench tower 1 first time purification gained propylene steam nitrile and form finished product product through the propylene steam nitrile of knockout tower secondary separation gained and discharged by quench tower 1.In this way, on the one hand, effectively can remove the ammonia in reaction gas, on the other hand, reduce the loss of vinyl cyanide in above-mentioned removal process.Make vinyl cyanide refine yield thus to improve, and promote the purity of propylene steam nitrile.
Continue with reference to Fig. 1, sulphuric acid soln transfer lime 3 and first is communicated with pipeline section 8 and is connected, be communicated with quench tower 1 to be communicated with pipeline section 8 by first, wherein, along first be communicated with pipeline section 8 from the direction to its tower top sidewall at the bottom of quench tower 1 tower, sulphuric acid soln transfer lime 3 and first is communicated with the first link position 10 that pipeline section 8 is connected, and is positioned at the downstream that the second connection pipeline section 9 and first is communicated with the second link position 11 that pipeline section 8 is connected.In other words, along first be communicated with pipeline section 8 from the direction to its tower top sidewall at the bottom of quench tower 1 tower, set gradually above-mentioned second link position 11 and the first link position 10.Make thus, the intermediate reaction product of quench tower 1 is by after the tower bottom outlet outflow of quench tower 1, and first through the second link position 11, the intermediate reaction product of a part is communicated with pipeline section 9 via second and enters in knockout tower 2.The intermediate reaction product of another part flows through the second link position 11 to be continued to flow along the first connection pipeline section 8.When the intermediate reaction product of above-mentioned another part flows to the first link position 10, sulphuric acid soln flows into the first connection pipeline section 8 through sulphuric acid soln transfer lime 3, and jointly flows into quench tower 1 after mixing with the intermediate reaction product of this another part.
With further reference to Fig. 1, in the present embodiment, vinyl cyanide system for separating and purifying also comprises reboiler 4 and steam manifold 5.Wherein, reboiler 4 is connected with knockout tower 2, and steam manifold 5 has the first branch road 12 and the second branch road 13, first branch road 12 is connected to reboiler 4, and the second branch road 13 is connected to knockout tower 2.Steam manifold 5 arranges shifter 14, and this shifter 14 steam controlled in steam manifold 5 enters the first branch road 12 or the second branch road 13.Alternatively, above-mentioned shifter 14 is T-valve.Particularly, have can the first channel of heat exchange and second passage mutually for reboiler 4.Wherein, the entrance of first channel is communicated with at the bottom of the tower of knockout tower 2, and the outlet of first channel is communicated with the sidewall of knockout tower 2, and the entrance of second passage is communicated with the first branch road 12 of steam manifold 5, and the outlet of second passage has phlegma recovery line 25.
When applying the vinyl cyanide system for separating and purifying of the present embodiment, the steam in steam manifold 5 is made to enter the first branch road 12 if select, the material be then positioned at the bottom of the tower of knockout tower 2 imports first channel, steam imports second passage through the first branch road 12, steam provides heat for the material in first channel, leads back to knockout tower 2 after the liquid in first channel is heated.Wherein, in the material at the bottom of tower of knockout tower 2, at least there is ammoniumsulphate soln, liquid propylene nitrile.Ammoniumsulphate soln and liquid propylene nitrile are heated in reboiler, the liquid propylene nitrile gasification of part forms gas-phase propene nitrile, this partial gas phase vinyl cyanide leads back to in knockout tower by knockout tower sidewall together with the liquid propylene nitrile do not gasified, ammoniumsulphate soln, be separated to realize secondary, secondary more isolated gas-phase propene nitrile is led back in quench tower 1 through third connecting pipeline section 22 by the tower top of knockout tower 2 again.
When applying the vinyl cyanide system for separating and purifying of the present embodiment, the steam in steam manifold 5 is made to enter the second branch road 13 if select, then steam is imported directly in knockout tower 2 to heat the reaction mass in knockout tower, make Partial Liquid Phase vinyl cyanide wherein be gasificated into gas-phase propene nitrile, be separated again to realize secondary.
To sum up, no matter select to make the steam in steam manifold 5 enter the first branch road 12 or the second branch road 13, steam all serves as the reaction mass in knockout tower 2 provides the effect of thermal source, gasify to make liquid propylene nitrile and form gas-phase propene nitrile, and enter quench tower 1 via the third connecting pipeline section 22 be communicated with knockout tower 2 tower top.And steam is condensed into water of condensation by phlegma recovery line 25 after flowing through second passage heat release.
In addition, in the present embodiment, be connected with bunch grade adjustment device between knockout tower 2 and steam manifold 5, bunch grade adjustment device comprises temperature monitor 15, flow monitor 16 and variable valve 17.Wherein, the tower top temperature of temperature monitor 15 pairs of knockout towers 2 is monitored, and controls according to monitor value the aperture that flow monitor 16 regulates variable valve 17.Preferably, tower top service temperature is positioned at the scope of 105 DEG C ~ 115 DEG C.In the present embodiment, tower top service temperature is 100 DEG C.Temperature monitor 15 detects the tower top temperature of knockout tower 2, and when tower top temperature is higher than 100 DEG C, temperature monitor 15 sends signal to flow detector 16.Flow detector 16 resets initial value after receiving signal, and then gives variable valve 17 signal, and variable valve 17 reduces aperture and then reduces steam addition.Final reduction tower top temperature.When tower top temperature is lower than 100 DEG C, variable valve 17 is made to increase aperture and then increase steam addition.When tower top temperature equals 100 DEG C, temperature monitor 15 does not carry out any operation.
In addition, in the present embodiment, at the bottom of the tower of quench tower 1 and between the second connection pipeline section 9, level monitoring device is connected with, wherein, level monitoring device, according to the liquid level of reaction mass in quench tower 1, controls to be communicated with by first the flow that pipeline section 8 flows into the intermediate reaction product of the second connection pipeline section 9.Particularly, the liquid level detector 23 detecting quench tower liquid level is set at quench tower 1, and be communicated with on pipeline section 9 second and valve 24 is set, when liquid level detector 23 detects quench tower liquid level higher than preset value, send signal to increase the aperture of valve 24 to valve 24, and then increase the ammoniumsulphate soln flow entering knockout tower 2.When liquid level detector 23 detects quench tower liquid level lower than preset value, send signal to reduce the aperture of valve 24 to valve 24, and then reduce the ammoniumsulphate soln flow entering knockout tower 2.When liquid level detector 23 detects that quench tower liquid level equals preset value, do not carry out any operation.Alternatively, liquid level detector 23, except having above-mentioned functions, also can have the function of instruction liquid level and warning.Preferably, be communicated with in pipeline section 8 with first between the second link position 11 at the bottom of the tower of quench tower 1 and be in series with recycle pump 7.Wherein, aborning, the determination of above-mentioned preset value depends primarily on two aspects: 1, the produced quantity of recycle pump 7 ensures that the amount of liquid in quench tower tower reactor has a certain amount of surge time, then sets predetermined level value (i.e. above-mentioned preset value) according to the diameter of this amount of liquid and quench tower.2, remove outside Article 1 chief reason, in an embodiment of the present invention, ensure more than the liquid level of the reaction gas entrance 20 of quench tower in quench tower.
With further reference to Fig. 1, in the present embodiment, sulphuric acid soln transfer lime 3 is communicated with between pipeline section 8 with first and is provided with pH value monitoring device, wherein, pH value monitoring device is communicated with the link position of pipeline section 8 with first, between the first link position 10 and the second link position 11, wherein, pH value monitoring device is communicated with the pH value of intermediate reaction product in pipeline section 8 according to first, controls sulphuric acid soln transfer lime 3 and is communicated with to first the operational throughput that pipeline section 8 carries sulphuric acid soln.Particularly, when the pH value of intermediate reaction product is lower than set(ting)value, reduce the operational throughput of sulphuric acid soln.When the pH value of intermediate reaction product is higher than set(ting)value, increase the operational throughput of sulphuric acid soln.When the pH value of intermediate reaction product equals set(ting)value, do not do any operation.Wherein, preferably, above-mentioned set(ting)value is positioned at the scope of 4.8-6.0.
Continue with reference to Fig. 1, in the present embodiment, knockout tower 2 bottom is connected with material recycle pipe 6, and in knockout tower 2, reaction mass can be discharged by material recycle pipe 6.Bottom knockout tower 2 and between material recycle pipe 6, be provided with fluid level control device, wherein, fluid level control device, according to the liquid level of reaction mass in knockout tower 2, controls the flow flowing into material to be recycled in material recycle pipe 6.Concrete setting is same as the level monitoring device for regulating quench tower 1, does not repeat them here.
By using above-mentioned bunch grade adjustment device, level monitoring device for quench tower, pH value monitoring device and one or more for separating of in the fluid level control device of tower, the steady running of this vinyl cyanide system for separating and purifying can be ensured, and ensure that each device is in good running status, refine yield to improve vinyl cyanide further, and promote the purity of propylene steam nitrile further.Certainly, the setting of each device above-mentioned is not limited to this, as long as can realize the control of liquid level to knockout tower 2, the liquid level of quench tower 1, the temperature of knockout tower 2 and the flow of sulphuric acid soln.
Alternatively, the tower top of quench tower 1 is provided with finished product product exit 18, aforementioned finished product product is discharged by finished product product exit 18, quench tower 1 inside is provided with the first spray equipment 19, the port that first spray equipment 19 is communicated with pipeline section 8 with first of the tower top sidewall being communicated to quench tower 1 is communicated with, ammoniumsulphate soln is communicated with pipeline section 8 with sulphuric acid soln through first and enters the first spray equipment 19, and sprays in quench tower 1 through the first spray equipment 19.By this structure, that can increase sulphuric acid soln with contact area that is ammonia, and the liquid propylene nitrile being conducive to carrying secretly in ammoniumsulphate soln departs from ammoniumsulphate soln gasification, and then the gas-phase propene nitrile after gasification can be discharged by finished product product exit 18.
In addition, be also provided with reaction gas entrance 20 at quench tower 1 sidewall, quench tower 1 inside is also provided with the second spray equipment 21, and wherein, reaction gas entrance 20 is communicated with the second spray equipment 21.Thus, can the contact area of ammonia in augmenting response gas and sulphuric acid soln, more ammonia can be reacted with sulphuric acid soln and generate ammoniumsulphate soln, to reduce the ammonia in finished product product.
In addition, tower tray is set in knockout tower 2, to strengthen separating effect.Be more preferably, 10 pieces of tower trays are set.
The material balance table of the process of vinyl cyanide refined by table 1 for applying said system.With reference to following table, A, B, C, D, E are the material balance point of five shown in Fig. 1.Wherein, A point is positioned on the pipeline that is connected with reaction gas entrance 20, with the component of detection reaction gas and its physical features.B point is positioned on the pipeline that is connected with finished product product exit 18, to detect component and its physical features of finished product product.C point is positioned on the second connection pipeline section 9, to detect component and its physical features of intermediate reaction product.D point is positioned on third connecting pipeline section 22, and with the secondary component of isolated gas-phase propene nitrile and its physical features again, this secondary more isolated gas-phase propene nitrile can be mingled with other gases.E point is positioned on material recycle pipe 6, to detect component and its physical features of the reaction mass of being discharged by separator 2.Said components and physical features are listed particularly in Table 1.
Table 1
Logistics number |
|
A |
B |
C |
D |
E |
Liquid phase fraction |
|
0.000 |
0.000 |
0.847 |
0.000 |
0.828 |
Temperature |
℃ |
255.0 |
82.9 |
84.1 |
109.5 |
111.0 |
Pressure |
MPA |
0.1540 |
0.1460 |
0.4600 |
0.1440 |
0.1520 |
Mass rate |
KG/HR |
135380.97 |
147005.06 |
11986.11 |
1361.35 |
10624.76 |
Liquid phase actual flow |
M
3/HR
|
|
|
10.51 |
|
9.24 |
Liquid phase actual density |
KG/M
3 |
|
|
965.93 |
|
952.03 |
Gas phase actual flow |
M
3/HR
|
141300.22 |
113943.84 |
|
1588.36 |
|
Gas phase actual density |
KG/M
3 |
0.96 |
1.29 |
|
0.86 |
|
Constituent mass flow |
KG/HR |
|
|
|
|
|
Vinyl cyanide |
KG/HR |
16917.68 |
16607.30 |
66.89 |
66.88 |
0.00 |
Acetonitrile |
KG/HR |
613.51 |
568.89 |
8.02 |
7.94 |
0.08 |
Prussic acid |
KG/HR |
1938.67 |
1762.26 |
8.18 |
8.17 |
0.00 |
Water |
KG/HR |
24014.16 |
36723.34 |
9394.79 |
1253.28 |
8141.51 |
Sulphur ammonium |
KG/HR |
0.00 |
0.00 |
1832.59 |
0.00 |
1832.59 |
Vinylformic acid |
KG/HR |
344.63 |
252.35 |
55.64 |
11.47 |
44.17 |
Propenal |
KG/HR |
178.74 |
134.06 |
0.81 |
0.81 |
0.00 |
Other components |
KG/HR |
91373.58 |
90956.86 |
619..19 |
12.79 |
606.4 |
These are only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.