CN212615653U

CN212615653U - A spray vacuum system for polycarbonate device

Info

Publication number: CN212615653U
Application number: CN202021157642.XU
Authority: CN
Inventors: 梁玮
Original assignee: Zhejiang Polycarbon Engineering Technology Co ltd
Current assignee: TOpen Technology (Quzhou) Co.,Ltd.
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2021-02-26
Anticipated expiration: 2030-06-19

Abstract

The utility model discloses a spray vacuum system for polycarbonate device, including at least two jet vacuum pump (2) of establishing ties each other, jet vacuum pump (2) including condenser (22) of ejector (21) that link to each other in proper order, its characterized in that: the system also comprises a power steam supply unit (1) for supplying the benzyl carbonate steam and a condensate supply unit (3) for supplying the benzyl carbonate liquid, wherein an outlet of the power steam supply unit (1) is communicated with the steam inlet (212) of the ejector (21), and an outlet of the condensate supply unit (3) is communicated with a condensate inlet (223) of the condenser (22). Compared with the prior art, the utility model discloses a jet vacuum system can avoid the adhesion thing to adhere to inside the system as far as possible.

Description

A spray vacuum system for polycarbonate device

Technical Field

The utility model relates to a polycarbonate device technical field specifically indicates a jet vacuum system for polycarbonate device.

Background

The polycarbonate has the excellent characteristics of transparency, excellent impact strength, heat resistance, cold resistance, dimensional stability, electric insulation and the like, and has great application value and application potential in the fields of industry, agriculture and the like. At present, polycarbonate synthesis mainly comprises two processes, namely a phosgene method and a non-phosgene molten ester exchange method, and compared with the phosgene method, the raw materials of the non-phosgene molten ester exchange method are clean, green and nontoxic, and the method is a current hot spot and is a future trend. In the production process of the non-phosgene melt transesterification method, no matter the transesterification reaction, the pre-polycondensation reaction or the final polymerization reaction, in order to remove phenol which is a byproduct generated in the reaction and ensure the yield, the reaction is required to be carried out under the high vacuum condition which is stable for a long time.

The vacuum systems adopted in the current devices mainly comprise a mechanical vacuum system, an injection vacuum system and the like.

The mechanical vacuum system, which uses several mechanical vacuum pumps connected in series, is the earliest vacuum system. Mechanical vacuum systems have the following disadvantages: on one hand, the mechanical vacuum pump contains a moving part which needs to move continuously, belongs to moving equipment, is easy to break down, and is difficult to ensure long-term stable operation, so that the whole system is usually required to be used and prepared, and the equipment investment is large; on the other hand, the air extraction rate of the mechanical vacuum pump is low, the size of the mechanical vacuum pump must be increased to meet the technological requirements, the size of the mechanical vacuum pump also has a bottleneck, and a plurality of mechanical pumps are required to be connected in parallel when necessary, so that the equipment investment is further increased.

Compared with a mechanical vacuum system, the main equipment of the jet vacuum system is static equipment, so that the fault rate is low and the system stability is good. According to different media, the injection vacuum system commonly used in the polycarbonate process at present mainly comprises:

(1) water vapor injection vacuum system: the vapor is used as power vapor, and cold water is used as condensate, so that the advantages of simple and easily obtained vapor and low operation cost are achieved, and the defects of poor compatibility of water with powder, oligomer, micromolecule organic matters and the like in the extracted gas and poor condensation effect are achieved. Meanwhile, water and phenol in the extracted gas form an acidic solution, which corrodes equipment. In addition, as water is an inorganic substance, under the action of high temperature and high vacuum, partial intermediate products and byproducts are hydrolyzed to release volatile substances with low boiling points, so that the vacuum degree is further influenced;

(2) phenol jet vacuum system: phenol vapor is used as power vapor, and low-temperature phenol is used as condensate (such as patent CN108916128A and utility model CN 205683977U). Compared with water, phenol has better compatibility, so the condensation effect is better. But the freezing point of phenol is higher, and phenol solid is easily formed to block the nozzle or adhere to the inner walls of the ejector and the condenser or the top of the end socket, so that the performance of the injection system is unstable, and the maintenance rate is high. The adhesive is easy to carbonize and coke after being adhered to the inside of the system for a long time, and can enter a process material system in the circulating process, so that a plurality of negative effects are brought to the performance of the polycarbonate product.

In addition, in the case of a polycarbonate device, after the gas brought out from the vacuum demand point enters the injection vacuum system, a part of impurities may be attached to the inside of the system.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a can avoid the adhesion thing to adhere to the inside injection vacuum system of system as far as possible for polycarbonate device is provided.

The utility model provides a technical scheme that above-mentioned technical problem adopted does: the utility model provides an injection vacuum system for polycarbonate device, is including the injection vacuum pump of at least two mutual series connection, the injection vacuum pump including the condenser of the ejector that links to each other in proper order, its characterized in that: the condenser is characterized by also comprising a power steam supply unit for supplying the benzyl carbonate steam and a condensate supply unit for supplying the benzyl carbonate liquid, wherein an outlet of the power steam supply unit is communicated with the steam inlet of the ejector, and an outlet of the condensate supply unit is communicated with the condensate inlet of the condenser.

In order to improve the contact area between the condensate and the steam and enhance the condensation effect, an atomization device capable of atomizing the liquid is arranged in the condenser, and the atomization device is connected to the condensate inlet of the condenser.

In order to realize the atomization of the condensate, the atomization device comprises

The top of the shell is provided with a liquid inlet communicated with the condensate inlet, and the peripheral wall of the shell is provided with a plurality of liquid outlets at intervals; and

the air guide sleeve is conical, corresponds to the liquid outlets one by one, covers the corresponding liquid outlets, and is provided with a spray hole extending spirally outwards from the liquid outlet.

In order to further avoid the adhesion of the adhesive on the inner wall of the condenser, the inner cavity of the shell is in a shape of being symmetrical up and down with the middle part being large and two ends being small, and the central axis of the air guide sleeve is basically perpendicular to the peripheral wall of the shell, so that the inner wall of the condenser is well washed, and the inner wall of the condenser is ensured to be free from adhesion of foreign matters.

In order to ensure the uniformity of the condensate after being sprayed, the air guide covers are arranged in rows from top to bottom, the air guide covers in each row are arranged at intervals along the circumferential direction of the shell, and the air guide covers in two adjacent rows are arranged in a staggered mode.

In order to discharge the non-condensable gas in time, a vacuum pump, preferably a liquid ring pump or a dry pump, is further included, and an inlet of the vacuum pump is communicated with a gas phase outlet of the last jet vacuum pump and is used for discharging the non-condensable gas from the gas phase outlet.

In order to prevent the condensable components in the mixed gas from being adhered to the inner wall of the ejector and further solve the second technical problem, the blocking risk and the maintenance rate of the system can be reduced, and the heat-insulating jacket is sleeved on the periphery of the ejector of the foremost jet vacuum pump.

In order to solve the problem of adhesion of the accumulated liquid and the oligomer and simultaneously avoid the influence on the connection strength caused by stress concentration at the connection point of the accumulated liquid and the oligomer and the condenser, an ejector of the foremost jet vacuum pump is obliquely arranged.

Preferably, the included angle between the ejector of the foremost jet vacuum pump and the horizontal plane is 5-30 degrees.

The number of the jet vacuum pumps is three or more than three in order to provide enough vacuum degree to remove phenol generated as a byproduct in the ester exchange reaction in time.

Compared with the prior art, the utility model has the advantages of:

firstly, supplying methyl phenyl carbonate steam as power steam of an ejector through a power steam supply unit, supplying methyl phenyl carbonate liquid as condensate of a condenser through a condensate supply unit, wherein the freezing point of methyl phenyl carbonate is about-31 ℃, is far lower than the freezing points of water and phenol (the freezing point of water is 0 ℃, and the freezing point of phenol is 45 ℃), adhesion substances are not easy to form and adhere to the inside of a system, and the methyl phenyl carbonate is used as an excellent solvent of polycarbonate and can be used for cleaning polymer solids from a polycarbonate device;

secondly, the special atomization device is arranged to continuously flush the condenser, thereby further avoiding the polymer solid from the polycarbonate device from adhering to the wall surface of the condenser;

and thirdly, an ejector of the most front jet vacuum pump is obliquely arranged, so that the polymer solid is favorably separated and is not adhered to the ejector.

Drawings

FIG. 1 is a schematic diagram of an embodiment of a jet vacuum system of the present invention;

FIG. 2 is a schematic diagram of the ejector vacuum pump of FIG. 1;

fig. 3 is a front view of an atomizing device in an embodiment of a jet vacuum system of the present invention;

fig. 4 is a top view of the atomizing device of fig. 3.

Detailed Description

The present invention will be described in further detail with reference to the following embodiments.

Fig. 1 to 4 show a preferred embodiment of the ejector vacuum system of the present invention. The jet vacuum system comprises a power steam supply unit 1, a condensate supply unit 3, a jet vacuum pump 2 and a vacuum pump 4.

Wherein the power steam supply unit 1 is used for supplying the benzyl carbonate steam. Specifically, the supplied power steam is superheated steam, the main component of the superheated steam is benzyl carbonate, the mass fraction of the benzyl carbonate is higher than 90 wt%, the rest components are one or more of diphenyl carbonate, phenol and bisphenol A, the pressure is preferably 101-120 kPa, and the temperature is preferably 200-250 ℃.

The condensate supply unit 3 is for supplying a benzyl carbonate liquid. Specifically, the main component of the supplied condensate is benzyl carbonate, the mass fraction of the main component is higher than 90 wt%, the rest components comprise one or more of phenol, diphenyl carbonate and bisphenol A, the temperature of the condensate is preferably 20-60 ℃, and the pressure of the condensate is preferably 0.1-1 MPa.

The number of the jet vacuum pumps 2 is at least two, and the jet vacuum pumps 2 are connected in series. In this embodiment, the number of the jet vacuum pumps 2 is three to satisfy the requirement of a higher vacuum degree.

Specifically, each ejector vacuum pump 2 includes an ejector 21 and a condenser 22. At least partial caliber of the ejector 21 is gradually contracted from top to bottom and then gradually expanded to be used as a venturi tube, the upper part of the ejector 21 is provided with an air suction port 211 for material to enter and a steam inlet 212 for power steam to enter, the lower part of the ejector 21 is provided with an exhaust port 213 for mixed gas to exhaust, and the steam inlet 212 is communicated with an outlet of the power steam supply unit 1; the lower part of the condenser 22 is provided with a gas phase inlet 221 and a condensate outlet 224, the upper part of the condenser 22 is provided with a gas phase outlet 222 and a condensate inlet 223, the gas phase inlet 221 is communicated with the exhaust port 213 of the ejector 21, and the condensate inlet 223 is communicated with the outlet of the condensate supply unit 3; the air inlet 211 of the foremost jet vacuum pump 2 is communicated with the vacuum demand point of the polycarbonate device, and the air inlet 211 of the latter jet vacuum pump 2 is communicated with the gas phase outlet 222 of the former jet vacuum pump 2.

In addition, the temperature in the ejector 21 of the foremost jet vacuum pump 2 is preferably 150-300 ℃, and the heat-insulating jacket 23 is sleeved on the periphery of the ejector 21, so that condensable components in the mixed gas are prevented from being adhered to the inner wall of the ejector 21, and the blocking risk and the maintenance rate of the system can be reduced; the ejector 21 of the most front jet vacuum pump 2 is obliquely arranged, and the included angle between the ejector 21 and the horizontal plane is 5-30 degrees, so that the problem of adhesion of accumulated liquid and oligomer is solved, and meanwhile, the influence on the connection strength caused by stress concentration at the connection point of the ejector and the condenser is avoided; inside each condenser 22 there is provided an atomizing device 24 capable of atomizing the liquid, which atomizing device 24 is connected at the condensate inlet 223.

As shown in fig. 3 and 4, the atomizing device 24 includes a housing 241 having a hollow interior and a flow guide cover 242 mounted on an outer wall of the housing 241. A liquid inlet 2411 communicated with the condensate inlet 223 is formed in the top of the shell 241, a plurality of liquid outlets 2412 are arranged on the peripheral wall of the shell 241 at intervals, the guide cover 242 is conical and is in one-to-one correspondence with the liquid outlets 2412, the guide cover covers the corresponding liquid outlets 2412, and spray holes 2421 extending from the liquid outlets 2412 outwards in a spiral shape are formed in the peripheral wall of the guide cover 242. In this embodiment, the shape of the inner cavity of the casing 241 is a shape with a large middle and two small ends, the two ends are symmetrical up and down, the central axis of the air guide sleeve 242 is substantially perpendicular to the outer peripheral wall of the casing 241, the air guide sleeves 242 are arranged in rows one above the other, the air guide sleeves 242 in each row are arranged at intervals along the circumferential direction of the casing 241, and the air guide sleeves 242 in two adjacent rows are arranged in a staggered manner. Above-mentioned atomizing device 24's setting can improve the area of contact between condensate and the steam on the one hand, strengthens the condensation effect, and on the other hand can play good washing effect to the inner wall of condenser 22, ensures that condenser 22's inner wall is free from the extraneous matter adhesion.

The inlet of the vacuum pump 4 communicates with the gas-phase outlet 222 of the final jet vacuum pump 2, and discharges the noncondensable gas from the gas-phase outlet 222.

The working principle of the utility model is as follows: after entering through the steam inlet 212, the power steam supplied by the power steam supply unit 1 increases in flow velocity and forms a partial vacuum, so that the extracted gas flows in from the air suction port 211 under the action of pressure difference, the extracted gas and the power steam are uniformly mixed when passing through the venturi tube, and are decelerated and pressurized at the expansion section of the venturi tube, then the mixed gas enters into the condenser 22 through the air exhaust port 213 and the gas phase inlet 221 in sequence, and contacts with uniformly dispersed condensate liquid drops in the middle of the condenser 22 in the ascending process to perform sufficient heat transfer and mass transfer, so that condensable components in the mixed gas are condensed, and a vacuum environment is formed again; the condensed waste liquid is discharged from the bottom condensate outlet 224, and the non-condensable gas is discharged from the gas phase outlet at the upper part of the condenser 22222 enters a next-stage ejector 21 or a vacuum pump 4, and the ejection vacuum system can generate high vacuum of 0.05kPa absolute pressure, and the suction quantity is 10000-100000 m³/h。

Through the contrast, adopt phenol as power medium, will lead to the vacuum not enough about general three month because of the adhesion problem, need park the washing, and adopt carbonic acid benzyl ester as power medium, and adopt the utility model discloses an improved design such as atomizer and ejector inclination set up, can move more than a year always, improved production cycle, saved a large amount of material consumptions, energy consumption.

Claims

1. The utility model provides a jet vacuum system for polycarbonate device, includes at least two jet vacuum pumps (2) that establish ties each other, jet vacuum pump (2) including condenser (22) that have consecutive ejector (21) of looks, its characterized in that: the system also comprises a power steam supply unit (1) for supplying the benzyl carbonate steam and a condensate supply unit (3) for supplying the benzyl carbonate liquid, wherein an outlet of the power steam supply unit (1) is communicated with the steam inlet (212) of the ejector (21), and an outlet of the condensate supply unit (3) is communicated with a condensate inlet (223) of the condenser (22).

2. The ejector vacuum system of claim 1, wherein: an atomization device (24) capable of atomizing liquid is arranged inside the condenser (22), and the atomization device (24) is connected to a condensate inlet (223) of the condenser (22).

3. The ejector vacuum system of claim 2, wherein: the atomization device (24) comprises a shell (241) with a hollow interior, the top of the shell is provided with a liquid inlet (2411) communicated with the condensate inlet (223), and the peripheral wall of the shell is provided with a plurality of liquid outlets (2412) at intervals; and

the conical air guide sleeve (242) corresponds to the liquid outlets (2412) one by one, covers the corresponding liquid outlets (2412), and is provided with a spray hole (2421) which extends outwards from the liquid outlets (2412) in a spiral shape on the peripheral wall.

4. A ejector vacuum system as in claim 3, wherein: the shape of casing (241) inner chamber is middle big both ends little and longitudinal symmetry, the axis of kuppe (242) is the basic perpendicular to the periphery wall of casing (241).

5. The ejector vacuum system of claim 4, wherein: the air guide sleeves (242) are arranged in rows from top to bottom, the air guide sleeves (242) in each row are arranged at intervals along the circumferential direction of the shell (241), and the air guide sleeves (242) in two adjacent rows are arranged in a staggered mode.

6. A ejector vacuum system as claimed in any one of claims 1 to 5, wherein: the device also comprises a vacuum pump (4), wherein the inlet of the vacuum pump (4) is communicated with the gas phase outlet (222) of the last jet vacuum pump (2) and is used for discharging the non-condensable gas from the gas phase outlet (222).

7. A ejector vacuum system as claimed in any one of claims 1 to 5, wherein: the periphery of an ejector (21) of the most front jet vacuum pump (2) is sleeved with a heat-insulating jacket (23).

8. A ejector vacuum system as claimed in any one of claims 1 to 5, wherein: the ejector (21) of the most forward ejector vacuum pump (2) is arranged obliquely.

9. The ejector vacuum system of claim 8, wherein: the included angle between the ejector (21) of the foremost jet vacuum pump (2) and the horizontal plane is 5-30 degrees.

10. A ejector vacuum system as claimed in any one of claims 1 to 5, wherein: the number of the jet vacuum pumps (2) is an integer of three or more.