CN210266701U - Linkage type heat exchanger - Google Patents

Abstract

The utility model relates to a linkage type heat exchanger, in particular to an ethylene cold storage gasification system for producing ethylbenzene, which comprises an upper layer heat exchange cylinder and a lower layer heat exchange cylinder, wherein a communicating pipe is arranged between the upper layer heat exchange cylinder and the lower layer heat exchange cylinder for connection; the upper-layer heat exchange cylinder comprises an upper partition plate, an upper flange, a plurality of upper heat exchange tubes, a left side guide plate, a right side guide plate and an overflow plate; the lower-layer heat exchange cylinder comprises a lower partition plate, a lower flange, a plurality of lower heat exchange tubes, a left directional guide plate and a right directional guide plate. The utility model discloses utilize refrigerant liquid, refrigerant gas's density difference, realize material circulation flow, heat transfer coefficient is high for the heat exchanger accomplishes heat transfer under the poor condition of low temperature, and realizes the convection heat transfer of material between upper and lower two-layer pipe side, shell side simultaneously.

Description

Linkage type heat exchanger

Technical Field

The utility model belongs to the chemical industry equipment field, concretely relates to in the equipment system that is arranged in the cold storage gasification of required raw materials ethylene of ethylbenzene production.

Background

Ethylbenzene is an important chemical raw material, and is mainly used for producing styrene as a chemical raw material monomer by dehydrogenation, the process route of benzene and ethylene alkylation is basically adopted in the production of ethylbenzene in the world at present, the production process of ethylbenzene is divided into a pure ethylene process (raw material ethylene is polymerization-grade ethylene) and a dilute ethylene process (raw material is ethylene-containing dry gas) according to different raw material ethylene sources, the supply of the latter is limited at present, 90% of ethylbenzene is produced by using polymerization-grade ethylene as a raw material, and the produced ethylbenzene is further subjected to dehydrogenation reaction to produce styrene.

The conventional process flow of ethylbenzene production is shown in fig. 1, wherein raw material benzene and ethylene are subjected to alkylation reaction in an alkylation reactor to generate ethylbenzene, and reaction materials enter a benzene recovery tower, an ethylbenzene recovery tower and a polyethylbenzene recovery tower system of a separation unit to be separated to obtain a product ethylbenzene. Raw material benzene required by the device is in a liquid phase, and enters an alkylation reactor after being pressurized by a circulating benzene pump; the raw material ethylene required by the device is in a gas phase, and the inlet pressure of the alkylation reactor is about 3.8MPaG, so the raw material ethylene needs to reach the pressure of 4.0MPaG to meet the reaction requirement of entering the reactor. The ethylene liquid in the tank area is stored under the conditions of normal pressure and low temperature (-103.7 ℃), so that the raw material ethylene for producing the ethylbenzene needs to be subjected to the technological process of pressurizing and vaporizing to 4.0MPaG gas phase to meet the requirement of producing the ethylbenzene. The utility model discloses set up promptly for realizing the vaporization pressure boost of raw materials ethylene.

The technical scheme of the vaporization and pressurization of raw material ethylene in the current industrialized ethylbenzene production is similar to that reported in patent CN102213361B, ethylene in a liquid ethylene storage tank is pressurized by a low-temperature ethylene immersed pump, pressurized ethylene is vaporized by a steam vaporizer, enters an ethylene compressor, is further pressurized and then is sent to a downstream ethylbenzene device. In which the shell side of a steam vaporizer uses a heat transfer medium to transfer energy between steam and ethylene, the process flow diagram reported in the patent is shown in fig. 2. The reported content is that domestic devices are commonly used, the process is imperfect, and the energy consumption of the devices is high: firstly, low-temperature ethylene is vaporized by using steam, and high-energy-consumption steam is consumed; secondly, the process of using an ethylene compressor for pressurizing ethylene leads to the increase of the total power consumption because the power consumption of gas phase compression is far greater than that of liquid phase pressurization; in addition, the cold energy of the ethylene is not fully utilized, so that the loss of the cold energy is brought, and the energy consumption of a chemical device is further increased; finally, since steam is used as a heat source, when the operation is not proper, the condensate of the steam has the possibility of being frozen and crystallized, which causes damage to equipment, ethylene leakage, and safety risk.

Other domestic patents relate to reports of low-temperature ethylene cold-storage gasification process systems, but all the processes are not used in an ethylbenzene device, and the main reasons are analyzed as follows.

Patents CN201410186491 and CN201420227457 disclose an energy-saving low-temperature ethylene vaporization process system using an economizer/recondenser, in the system, a low-temperature ethylene pump is arranged in a low-temperature liquid ethylene storage tank, the economizer is connected with the low-temperature liquid ethylene storage tank, the low-temperature ethylene pump pressurizes and conveys low-temperature ethylene in the low-temperature liquid ethylene storage tank to the economizer, BOG in the low-temperature liquid ethylene storage tank is compressed by a BOG compressor unit and then condensed into ethylene in the economizer, the ethylene further enters an ethylene booster pump inlet, and the pressurized ethylene is vaporized and output through an ethylene evaporator. The patent does not consider the situation that the BOG gas phase component amount is large, at the moment, partial liquid ethylene can be vaporized when the ethylene gas is condensed by an economizer, pump cavitation can be caused when the vaporized ethylene enters an ethylene booster pump, the ethylene booster pump cannot normally operate, and when the loading and unloading mode of an ethylene storage tank is a tank car, the problem is more likely to occur. In addition, since the ethylene output of the ethylbenzene plant is determined based on capacity, the output of low temperature ethylene is limited, and the BOG compressor is required for pressure control of the ethylene storage tank, when the downstream plant has a low ethylene demand or does not require such low temperature ethylene delivery, the BOG gas will not be condensed, so that the method has certain potential safety hazard.

Patent CNCN201521101583 utility model relates to an economizer that liquid ethylene gasification heat utilized, including ethylene booster pump, ethylene heat exchanger and ethylene vaporizer, the shell side medium of ethylene heat exchanger is the cryogenic fluid, is the special material that the freezing point is below-100 ℃, and ethylene is as the tube side medium, and the heat and the vaporization of shell side cryogenic fluid are absorbed to the liquid ethylene of tube side and heat up. The system is only suitable for the vaporization of ethylene produced by an ethylbenzene device because the refrigerating fluid is a substance with the temperature below freezing point-100 ℃, the refrigerating fluid used by the ethylbenzene device is an ethylene glycol aqueous solution with the temperature below freezing point-25 ℃, and the ethylene glycol aqueous solution is possibly frozen when contacting ethylene with the temperature of low-103.7 ℃ to bring potential safety hazards. In addition, the process does not consider the problems of gas-phase ethylene treatment, ethylene source and the like of an ethylene cold storage system, and does not have industrial implementation possibility.

Patents CN201620203850 and CN201620204162 disclose a low-temperature ethylene vaporization and cold energy recovery device. The device sends low-temperature liquid ethylene into an ethylene gasifier from a low-temperature ethylene storage tank, the low-temperature liquid ethylene exchanges heat with intermediate heat medium from a heat exchange gasifier to release a large amount of cold energy, the liquid ethylene is gasified, and the gaseous intermediate heat medium is liquefied and then returns to the lower space of the heat exchange gasifier to exchange heat with the material at the bottom of the heat exchanger, so that partial cold energy of the low-temperature ethylene is recycled; after the cold energy is transferred, the intermediate heat medium is heated again to be gasified and recycled. Thereby not only realizing the recovery of cold energy of the low-temperature ethylene, but also reducing the energy consumed for heating the ethylene. The technology utilizes an intermediate heating medium to transfer heat, temperature difference is needed for heat exchange of two heat exchangers, refrigerating fluid needs to keep certain temperature difference with ethylene vaporization temperature, and therefore the technology can only be applied to a low-pressure vaporization system to recover cold, for example, an EO device is used as a case, because the ethylene vaporization pressure needed by the EO device is about 2.0MPAG, the temperature difference between the refrigerating fluid and the ethylene vaporization temperature is more than 20 ℃, and vaporization is easy to realize. Above an ethylene vaporization pressure of 3.0MPAG, this version does not meet the use requirements, whereas the ethylbenzene plant requires an ethylene vaporization pressure of 4.0 MPAG.

Patent CN201820802578 discloses a ethylene method chloroethylene device ethylene low temperature cold volume utilizes system, make full use of the cold volume of low temperature raw materials ethylene, make most propylene gas then by ethylene liquid condensation in first propylene condenser to but the load of the propylene compressor that significantly reduces practices thrift power consumption and second propylene condenser well circulating water quantity, has practiced thrift ethylene gasification's steam consumption simultaneously. This system is similar to CN201410186491 and CN201420227457, and can save part of energy consumption when used in vinyl chloride plant, and is not suitable for ethylbenzene plant production.

Patent CN201821074397 discloses a novel circulating water return water bath formula ethylene vaporizer device, including circulating water return water pressure boost tubing pump, water bath formula ethylene vaporizer and the ethylene buffer tank of establishing ties in proper order, circulating water return water pressure boost tubing pump outside provides the circulating water through the external pipe of circulating water return water, sends into water bath formula ethylene vaporizer as the heating heat source behind the circulating water return pressure boost tubing pump pressure boost. The novel heating device adopts circulating water backwater as a heating heat source, is mild in operation and easy to control; circulating water return is used as a heating heat source, so that the equipment structure is compact, and the floor area of the device is reduced; the circulating water backwater is adopted as a heating heat source, compared with the steam, the energy consumption of the device is greatly reduced, the operation cost is reduced, and the economic benefit of the operation of the device is improved.

The ethylbenzene plant is a production plant taking ethylene as a raw material, and low-temperature raw material ethylene is required to be vaporized and pressurized to be 4.0MPaG gas at normal temperature during production of the plant; the low-temperature chilled water of the device for producing styrene by ethylbenzene dehydrogenation adopts glycol aqueous solution with the temperature of about 5 ℃, and the chilled water is generally obtained by refrigerating through an ice machine; therefore, from the perspective of the comprehensive utilization of the energy of the ethylbenzene plant, the optimal scheme of the ethylene used by the ethylbenzene plant is to recover the ethylene cold energy at the temperature of-103 ℃ by using the ethylene glycol aqueous solution for vaporization, on one hand, the ethylene is vaporized to meet the requirement of 4.0MPaG pressure, on the other hand, the ethylene cold energy is recovered by using the ethylene glycol aqueous solution for cooling, an ice maker is replaced, and the energy consumption is reduced. But the technical difficulty of the optimal scheme is high, on one hand, the freezing point of the ethylene glycol aqueous solution is-25 ℃, and when the ethylene is directly contacted with low-temperature ethylene, the risk of icing exists; on the other hand, if the intermediate refrigerants disclosed in the patents CN201620203850 and CN201620204162 are adopted for heat exchange, the temperature difference between the ethylene vaporization temperature of 1 ℃ and the required ethylene glycol aqueous solution of 5 ℃ is too small under the condition of 4.0MPaG because the polymerization-grade ethylene pressure and the polymerization-grade ethylene temperature are basically in one-to-one correspondence, and the heat exchange vaporization cannot be realized. Therefore, the existing reports can not realize the simultaneous realization of ethylene vaporization and cold energy recovery, and the industrial ethylbenzene device adopts the mode of indirectly vaporizing ethylene by water vapor or pressurizing by a compressor to operate, although the operation is stable, the steam consumption is high, and the energy consumption of the device is high.

Disclosure of Invention

The utility model discloses an aim at can only use the current situation of steam vaporization or gas phase compressor pressure boost to the raw materials ethylene vaporization system to current ethylbenzene device, provides a linkage type heat exchanger, and it utilizes refrigerant liquid, refrigerant gas's density difference, realizes the circulation flow of upper and lower two-layer material, and heat transfer efficiency is good to can realize the cold volume recovery vaporization technology of liquid phase pressure boost.

In order to realize the purpose, the technical scheme of the utility model is that:

a linkage heat exchanger, the ethylene used for producing ethylbenzene stores the gasification system cold, including upper heat exchange tube and lower floor heat exchange tube, there are communicating pipes to link between said upper, lower floor heat exchange tube;

the upper-layer heat exchange cylinder comprises an upper partition plate, an upper flange, a plurality of upper heat exchange tubes, a left side guide plate, a right side guide plate and an overflow plate; the upper-layer heat exchange cylinder is divided into an inlet area and an outlet area and a heat exchange area by the upper flange, and the inlet area and the outlet area are divided into an inlet area and an outlet area by the partition plate; a raw material inlet and a raw material outlet are respectively arranged on the upper layer heat exchange cylinder body corresponding to the inlet area and the outlet area; a refrigerant material emptying port is formed in the top of the heat exchange area; the upper heat exchange tubes are fixed in the heat exchange area through flanges, the inlet ends of the upper heat exchange tubes penetrate through the flanges to be communicated with the inlet area, and the outlet ends of the upper heat exchange tubes penetrate through the flanges to be connected with the outlet area;

the left and right guide plates are vertically fixed in the heat exchange area and form a convection channel longitudinally corresponding to the communicating pipe between the two plates, and the upper and lower ends of the left and right guide plates are respectively spaced from the shell of the upper heat exchange cylinder; the upper heat exchange tubes are distributed on two sides of the left and right guide plates; the overflow plates are arranged at the bottom of the upper-layer heat exchange cylinder body and positioned at the two sides of the communicating pipe, and an overflow gap is reserved between the overflow plates and the guide plates at the same side;

the lower-layer heat exchange cylinder comprises a lower partition plate, a lower flange, a plurality of lower heat exchange tubes, a left directional flow guide plate and a right directional flow guide plate; the lower flange divides the lower layer heat exchange cylinder into an inlet cavity and an outlet cavity and a heat exchange cavity, and the inlet cavity and the outlet cavity are divided into an inlet cavity and an outlet cavity by the lower partition plate; a material flow inlet and a material flow outlet are respectively arranged on the lower layer heat exchange cylinder body corresponding to the inlet cavity and the outlet cavity; a refrigerant material exhaust port is formed in the bottom of the heat exchange cavity, and a refrigerant material inlet is formed in the upper part of the heat exchange cavity; the lower heat exchange tubes are fixed in the heat exchange cavity through flanges, the inlet ends of the lower heat exchange tubes penetrate through the flanges to be communicated with the inlet cavity, and the outlet ends of the lower heat exchange tubes penetrate through the flanges to be connected with the outlet cavity;

the lower heat exchange tubes are fixed in the middle of the lower heat exchange barrel in a centralized manner; the left and right directional guide plates surround the two sides of the lower heat exchange tubes through bending and form guide channels with the inner walls of the lower heat exchange cylinders; an airflow channel longitudinally corresponding to the communicating pipe is formed between the two plates at the upper ends of the left and right directional guide plates by bending while the flow guide channel is formed.

The utility model discloses utilize refrigerant liquid, refrigerant gas's density difference, realize material circulation flow, heat transfer coefficient is high for the heat exchanger accomplishes heat transfer under the poor condition of low temperature, and realizes the convection heat transfer of material between upper and lower two-layer pipe side, shell side simultaneously.

Drawings

FIG. 1 is a block diagram of a conventional process for the production of ethylbenzene in accordance with the present invention;

FIG. 2 is a block diagram of an ethylene vaporization system using low pressure steam as a heat transfer medium;

fig. 3 is a block diagram of an ethylene cold storage gasification system according to the present invention;

fig. 4 is a schematic structural diagram of the middle linkage heat exchanger of the present invention;

FIG. 5 is a schematic sectional view A-A of FIG. 4.

Detailed Description

In order to enhance the understanding of the present invention, the present invention will be described in further detail with reference to the accompanying drawings and examples.

The first embodiment is as follows: as shown in fig. 4, the linkage heat exchanger in this embodiment includes an upper heat exchange cylinder 11, a lower heat exchange cylinder 21, and a communicating pipe 31 communicating the upper heat exchange cylinder and the lower heat exchange cylinder.

As shown in fig. 4 and 5, the upper layer heat exchange cylinder 11 includes an upper partition 112, an upper flange 111, a plurality of upper heat exchange tubes 116, a left baffle 120, a right baffle 121, and an overflow plate 122. The upper layer heat exchange cylinder body is divided into an inlet area, an outlet area and a heat exchange area 115 by an upper flange 111, and the inlet area and the outlet area are divided into an inlet area 113 and an outlet area 114 by partition plates; the inlet area is provided with a raw material inlet 118, and the outlet area is provided with a raw material outlet 119; a refrigerant material emptying port 117 is formed in the top of the heat exchange area; the upper heat exchange tubes 116 are fixed to the heat exchange area by flanges, and the inlet ends of the upper heat exchange tubes pass through the flanges to be communicated with the inlet area, and the outlet ends of the upper heat exchange tubes pass through the flanges to be connected with the outlet area.

As shown in fig. 5, the left and right guide plates are vertically fixed in the heat exchange zone and form a convection passage 123 longitudinally corresponding to the communication pipe between the two plates; the upper and lower ends of the left and right guide plates are respectively spaced from the shell of the upper heat exchange cylinder 11; a plurality of upper heat exchange tubes 116 are distributed on both sides of the left and right guide plates; the overflow plates 122 are arranged at the bottom of the upper layer heat exchange cylinder body and positioned at two sides of the communicating pipe 31, and an overflow gap is reserved between the overflow plates and the guide plates at the same side.

As shown in fig. 4 and 5, the lower heat exchange cylinder 21 comprises a lower partition 212, a lower flange 211, a plurality of lower heat exchange tubes 216, a left directional guide plate 221 and a right directional guide plate 222; the lower flange 211 divides the lower layer heat exchange cylinder into an inlet cavity, an outlet cavity and a heat exchange cavity 215, and the inlet cavity and the outlet cavity are divided into an inlet cavity 213 and an outlet cavity 214 by a lower partition plate; a material flow inlet 218 and a material flow outlet 219 are respectively arranged on the lower layer heat exchange cylinder body corresponding to the inlet cavity and the outlet cavity; a refrigerant material exhaust port 217 is formed in the bottom of the heat exchange cavity, and a refrigerant material inlet 220 is formed in the upper part of the heat exchange cavity; the lower heat exchange tubes 216 are fixed in the heat exchange cavity 215 through flanges, the inlet ends of the lower heat exchange tubes penetrate through the flanges to be communicated with the inlet cavity, and the outlet ends of the lower heat exchange tubes penetrate through the flanges to be connected with the outlet cavity;

the lower heat exchange tubes 216 are fixed in the middle of the lower heat exchange cylinder in a centralized manner; the left and right directional guide plates surround the two sides of the lower heat exchange tubes 216 through bending and form a guide channel 223 with the inner wall of the lower heat exchange cylinder; an airflow channel 224 longitudinally corresponding to the communicating pipe is formed between the two plates at the upper ends of the left and right directional guide plates by bending while forming the guide channel 223.

In this embodiment, the refrigerant liquid at the bottom of the lower heat exchange cylinder 21 is vaporized after heat exchange to form refrigerant gas which rises through the airflow channel 224 and the communicating pipe 31 to enter the convection channel 123; the refrigerant liquid formed after the heat exchange of the refrigerant gas descends, and the refrigerant liquid passes through the overflow plate 122 and enters the communicating pipe 31 along the rear edge wall and then returns to the bottom of the lower-layer heat exchange cylinder 21 along the flow guide channel 223, so that the convection heat transfer of shell side materials is realized, the heat transfer coefficient is enhanced, and the heat exchanger completes the heat transfer under the condition of low temperature difference. In the embodiment, the density difference of the refrigerant liquid and the refrigerant gas is utilized to realize material circulation flow and enhance the heat transfer efficiency.

As shown in fig. 3: the system comprises a normal pressure ethylene storage tank 2, a low temperature ethylene compressor, an ethylene cooler 7, an ethylene pump 3, a linkage type heat exchanger 1, an ethylene gasifier 4, an ethylene buffer tank 5 and an ethylbenzene device 6. Wherein the normal pressure ethylene storage tank 2 is connected with a raw material inlet 119 of an upper layer heat exchange cylinder of the linkage type heat exchanger through an ethylene pump 3; the raw material outlet 119 of the upper layer heat exchange cylinder is connected with the inlet on the tube side of the ethylene gasifier 4; the outlet on the pipe side of the ethylene gasifier 4 is connected with the inlet of an ethylene buffer tank 5; the ethylene buffer tank 5 is used for providing required ethylene for the ethylbenzene device 6; the shell side inlet raw material of the ethylene gasifier 4 is provided by an ethylbenzene plant; the shell side outlet of the ethylene vaporizer is connected to the tube side inlet 218 of the lower heat exchange drum, and the tube side outlet 219 of the lower heat exchange drum is supplied with coolant for the ethylbenzene plant.

In the implementation, chilled water is arranged on the middle tube side of the lower-layer heat exchange cylinder, refrigerant liquid is arranged on the shell side of the lower-layer heat exchange cylinder, and the temperature of the chilled water is reduced to 5 ℃ after the refrigerant liquid is heated and vaporized; the low-temperature ethylene is arranged on the tube side in the upper-layer heat exchange cylinder, the refrigerant gas is arranged on the shell side, the ethylene condenses the refrigerant gas into liquid through heat exchange, and the refrigerant liquid flows back to the lower-layer heat exchange cylinder through the communicated tube wall.

The above-mentioned technical solutions of the present invention are only used for illustration and not for limitation, and other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions.

Claims (1)

1. The utility model provides a linkage type heat exchanger for the cold storage gasification system of ethylene of production ethylbenzene which characterized in that: the heat exchange device comprises an upper layer heat exchange cylinder and a lower layer heat exchange cylinder, wherein a communicating pipe is arranged between the upper layer heat exchange cylinder and the lower layer heat exchange cylinder and is connected with the upper layer heat exchange cylinder and the lower layer heat exchange cylinder; the upper-layer heat exchange cylinder comprises an upper partition plate, an upper flange, a plurality of upper heat exchange tubes, a left side guide plate, a right side guide plate and an overflow plate; the upper-layer heat exchange cylinder is divided into an inlet area and an outlet area and a heat exchange area by the upper flange, and the inlet area and the outlet area are divided into an inlet area and an outlet area by the partition plate; a raw material inlet and a raw material outlet are respectively arranged on the upper layer heat exchange cylinder body corresponding to the inlet area and the outlet area; a refrigerant material emptying port is formed in the top of the heat exchange area; the upper heat exchange tubes are fixed in the heat exchange area through flanges, the inlet ends of the upper heat exchange tubes penetrate through the flanges to be communicated with the inlet area, and the outlet ends of the upper heat exchange tubes penetrate through the flanges to be connected with the outlet area; the left and right guide plates are vertically fixed in the heat exchange area and form a convection channel longitudinally corresponding to the communicating pipe between the two plates, and the upper and lower ends of the left and right guide plates are respectively spaced from the shell of the upper heat exchange cylinder; the upper heat exchange tubes are distributed on two sides of the left and right guide plates; the overflow plates are arranged at the bottom of the upper-layer heat exchange cylinder body and positioned at two sides of the communicating pipe, and an overflow gap is reserved between the overflow plates and the guide plates at the same side; the lower-layer heat exchange cylinder comprises a lower partition plate, a lower flange, a plurality of lower heat exchange tubes, a left directional flow guide plate and a right directional flow guide plate; the lower flange divides the lower layer heat exchange cylinder into an inlet cavity and an outlet cavity and a heat exchange cavity, and the inlet cavity and the outlet cavity are divided into an inlet cavity and an outlet cavity by the lower partition plate; a material flow inlet and a material flow outlet are respectively arranged on the lower layer heat exchange cylinder body corresponding to the inlet cavity and the outlet cavity; a refrigerant material exhaust port is formed in the bottom of the heat exchange cavity, and a refrigerant material inlet is formed in the upper part of the heat exchange cavity; the lower heat exchange tubes are fixed in the heat exchange cavity through flanges, the inlet ends of the lower heat exchange tubes penetrate through the flanges to be communicated with the inlet cavity, and the outlet ends of the lower heat exchange tubes penetrate through the flanges to be connected with the outlet cavity; the lower heat exchange tubes are fixed in the middle of the lower heat exchange barrel in a centralized manner; the left and right directional guide plates surround the two sides of the lower heat exchange tubes through bending and form guide channels with the inner walls of the lower heat exchange cylinders; an airflow channel longitudinally corresponding to the communicating pipe is formed between the two plates at the upper ends of the left and right directional guide plates by bending while the flow guide channel is formed.

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