Slurry steam stripping heat recovery system

Abstract

The utility model provides a slurry steam stripping heat recovery system, which relates to the technical field of polyvinyl chloride production, and comprises a stripping tower, a heat exchanger, a heat exchanger, a heat exchanger and a heat recovery device, and is characterized in that the stripping tower is provided with a cold slurry inlet, a steam inlet, a hot slurry outlet and a mixed gas outlet; the first heat exchanger is used for carrying out heat exchange on streams in a cold slurry inlet of the stripping tower and a hot slurry outlet of the stripping tower; an inlet of the condenser is connected with a mixed gas outlet of the stripping tower; and the second heat exchanger is connected between the mixed gas outlet of the stripping tower and the inlet of the condenser. A second heat exchanger is additionally arranged between the stripping tower and the condenser to recover the heat of the mixed gas, and the mixed gas which is not completely cooled is cooled through the condenser. And heat recovered from the mixed gas by the second heat exchanger can be used by other systems. Before entering the stripping tower, the cold PVC slurry exchanges heat with the hot PVC slurry heated from the stripping tower in the first heat exchanger to preheat the cold PVC slurry, so that the amount of steam supplemented by the stripping tower is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of polyvinyl chloride production, in particular to a slurry stripping heat recovery system. Background Art

[0002] The company adopts the suspension method to produce polyvinyl chloride. In the slurry stripping part, the current polymerized slurry stripping tower uses medium-pressure steam to enter from the bottom of the tower, and countercurrent heat exchange is performed with the cold PVC slurry entering from the top of the tower to remove vinyl chloride monomer from the PVC slurry to produce non-toxic resin; the hot PVC slurry after heat exchange is sent out from the bottom of the tower to the drying system for dehydration, and the mixed gas of steam and vinyl chloride comes out from the top of the tower and passes through the condenser to condense and separate the steam, and the vinyl chloride gas enters the recovery system for reuse. Before the cold PVC slurry enters the stripping tower, it exchanges heat with the hot PVC slurry coming out from the bottom of the stripping tower in the spiral plate heat exchanger to save the amount of steam added to the stripping tower.

[0003] The existing solutions have the following technical problems:

[0004] The mixed gas (steam + vinyl chloride) coming out from the top of the stripping tower is condensed by the circulating water condenser to achieve gas-liquid separation. The heat of the mixed gas is not recovered and is all taken away by the circulating water and dissipated into the atmosphere, causing waste.

[0005] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or any form of implication that the information constitutes the prior art known to those skilled in the art. Utility Model Content

[0006] In view of the above situation, the utility model provides a slurry stripping heat recovery system, aiming to solve the technical problems pointed out in the above background technology.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] The utility model provides a slurry stripping heat recovery system, comprising:

[0009] A stripping tower having a cold slurry inlet, a steam inlet, a hot slurry outlet and a mixed gas outlet;

[0010] a first heat exchanger for exchanging heat between streams at a cold slurry inlet of the stripping tower and a hot slurry outlet of the stripping tower;

[0011] a condenser, the inlet of which is connected to the mixed gas outlet of the stripping tower;

[0012] The second heat exchanger is connected between the mixed gas outlet of the stripping tower and the inlet of the condenser.

[0013] In some embodiments of the present invention, the heat exchange area of ​​the second heat exchanger is 30m².

[0014] In some embodiments of the present invention, the second heat exchanger has a cold desalted water inlet and a desalted water outlet.

[0015] In some embodiments of the utility model, it also includes a soda mixer, a hot desalted water tank and a polymerization kettle connected in sequence;

[0016] The steam-water mixer has a steam inlet and a desalted water inlet; the desalted water inlet of the steam-water mixer is connected to the desalted water outlet of the second heat exchanger.

[0017] In some embodiments of the present invention, the first heat exchanger is a spiral plate heat exchanger.

[0018] In some embodiments of the present invention, the heat exchange area of ​​the first heat exchanger is 120m².

[0019] In some embodiments of the present invention, a feeding tank is further included, and the cold slurry inlet of the stripping tower is connected to the outlet of the feeding tank.

[0020] In some embodiments of the present invention, the hot slurry outlet of the stripping tower is connected to a dry mixing tank.

[0021] In some embodiments of the present invention, a gas-liquid separation component is further included, and a feed end of the gas-liquid separation component is connected to a discharge port of the condenser.

[0022] In some embodiments of the present invention, the gas-liquid separation component includes a gas-liquid separation tank, a wastewater tank and a mother night pool; the inlet of the gas-liquid separation tank is connected to the discharge port of the condenser, and the liquid phase outlet of the gas-liquid separation tank is connected to the inlet of the wastewater tank; the liquid phase outlet of the wastewater tank is connected to the inlet of the mother night pool.

[0023] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0024] 1. A second heat exchanger is added between the stripping tower and the condenser to recover the heat of the mixed gas. The mixed gas that is not completely cooled is then cooled by the condenser. The heat recovered from the mixed gas by the second heat exchanger can be used by other systems.

[0025] 2. Before the cold PVC slurry enters the stripping tower, it exchanges heat with the hot PVC slurry heated from the stripping tower in the first heat exchanger to preheat the cold PVC slurry, thereby saving the amount of steam added to the stripping tower.

[0026] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a schematic diagram of the structure of the slurry stripping heat recovery system.

[0029] icon:

[0030] 1- Feeding trough,

[0031] 2-stripping tower, 21-cold slurry inlet of the stripping tower, 22-steam inlet of the stripping tower, 23-hot slurry outlet of the stripping tower, 24-mixed gas outlet of the stripping tower,

[0032] 3- The first heat exchanger,

[0033] 4- Condenser,

[0034] 51-gas-liquid separation tank, 52-wastewater tank, 53-mother night pool, 54-continuous compressor,

[0035] 6-second heat exchanger, 61-cold desalted water inlet, 62-desalted water outlet,

[0036] 7- Dry mixing tank,

[0037] 81-soft water mixer, 82-hot desalinated water tank. DETAILED DESCRIPTION

[0038] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can appreciate, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention.

[0039] In the description of the embodiments of the present utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0040] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0041] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] See also Figure 1 This embodiment provides a slurry stripping heat recovery system, including a feeding tank 1, a stripping tower 2, a first heat exchanger 3, a condenser 4, a gas-liquid separation component and a second heat exchanger 6.

[0044] The feeding tank 1 is used to supply the cold PVC slurry to the stripping tower 2.

[0045] The stripping tower 2 has a cold slurry inlet, a steam inlet, a hot slurry outlet and a mixed gas outlet;

[0046] The mixed gas outlet 21 of the stripping tower is connected to the outlet of the feeding tank 1 for introducing cold PVC slurry.

[0047] The mixed gas outlet 22 of the stripping tower is used to introduce steam to heat the cold PVC slurry.

[0048] The mixed gas outlet 23 of the stripping tower is used to discharge the hot PVC slurry into the dry mixing tank 7.

[0049] The mixed gas outlet 24 of the stripping tower is used to discharge the mixed gas (steam + vinyl chloride).

[0050] The first heat exchanger 3 is used to perform heat exchange between the streams in the mixed gas outlet 21 of the stripping tower and the mixed gas outlet 23 of the stripping tower.

[0051] In a specific implementation scenario, the first heat exchanger 3 is a spiral plate heat exchanger, and the heat exchange area of ​​the first heat exchanger 3 is 120 m² (the existing one is 80 m²).

[0052] The inlet of the condenser 4 is connected to the mixed gas outlet 24 of the stripping tower. In a specific implementation scenario, the condenser 4 uses circulating water as a cold source.

[0053] The feed end of the gas-liquid separation component is connected to the discharge port of the condenser 4 for separating the gas phase and the liquid phase. The gas-liquid separation component includes a gas-liquid separation tank 51, a wastewater tank 52 and a mother night pool 53. The inlet of the gas-liquid separation tank 51 is connected to the discharge port of the condenser 4, the gas phase outlet of the gas-liquid separation tank 51 is connected to the recovery condensation system through a continuous compressor 54, and the liquid phase outlet of the gas-liquid separation tank 51 is connected to the inlet of the wastewater tank 52. The liquid phase outlet of the wastewater tank 52 is connected to the inlet of the mother night pool 53.

[0054] The second heat exchanger 6 is connected between the mixed gas outlet 24 of the stripping tower and the inlet of the condenser 4, and is used to recover the heat in the mixed gas; the heat recovered from the mixed gas by the second heat exchanger 6 can be used by other equipment.

[0055] In a specific implementation scenario, the second heat exchanger 6 has a cold desalted water inlet 61 and a desalted water outlet 62, and the second heat exchanger 6 uses cold desalted water as a cold source; the heat exchange area of ​​the second heat exchanger 6 is 30m².

[0056] In combination with the above content, this embodiment has at least the following beneficial effects:

[0057] 1. A second heat exchanger 6 is added between the stripping tower 2 and the condenser 4 to recover the heat of the mixed gas, and the mixed gas that is not completely cooled is cooled again by the condenser 4. The heat recovered from the mixed gas by the second heat exchanger 6 can be used by other systems.

[0058] 2. Before the cold PVC slurry enters the stripping tower 2, it exchanges heat with the hot PVC slurry heated from the stripping tower 2 in the first heat exchanger 3 to preheat the cold PVC slurry, thereby saving the amount of steam added to the stripping tower 2.

[0059] 3. Increase the heat exchange area of ​​the first heat exchanger 3 from 80m² to 120m², and increase the heat recovery of hot PVC slurry (currently using a spiral plate heat exchanger with a heat exchange area of ​​80m², the heat exchange area is insufficient, and the heat recovery of hot PVC slurry is not sufficient. After preheating, the cold PVC slurry is only 83°C, and there is still room for improvement in heat utilization).

[0060] Example 2

[0061] This embodiment, based on the first embodiment, illustrates the utilization method of “heat recovered from the mixed gas by the second heat exchanger 6”.

[0062] See also Figure 1 In this embodiment, the slurry stripping heat recovery system also includes a steam-water mixer 81, a hot desalted water tank 82 and a polymerization kettle which are connected in sequence.

[0063] The steam-water mixer 81 has a steam inlet and a desalted water inlet; the desalted water inlet of the steam-water mixer 81 is connected to the desalted water outlet 62 of the second heat exchanger 6 .

[0064] In combination with the above content, this embodiment has at least the following beneficial effects:

[0065] The cold desalted water enters the second heat exchanger 6, is heated by the steam-water mixer 81, and is then sent to the hot desalted water tank and finally added to the polymerization kettle as a polymerization reaction carrier; that is, this embodiment connects the polymerization kettle and the stripping tower 2 that were originally unrelated, and uses the heat recovered from the mixed gas by the second heat exchanger 6 to heat the cold desalted water (supplying the polymerization kettle), thereby reducing the amount of steam added to the steam-water mixer 81.

[0066] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. In the absence of conflicts, the embodiments of the present application and the features in the embodiments may be combined with each other at will. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A slurry stripping heat recovery system, characterized in that: include: A stripping tower having a cold slurry inlet, a steam inlet, a hot slurry outlet and a mixed gas outlet; a first heat exchanger for exchanging heat between streams at a cold slurry inlet of the stripping tower and a hot slurry outlet of the stripping tower; a condenser, the inlet of which is connected to the mixed gas outlet of the stripping tower; The second heat exchanger is connected between the mixed gas outlet of the stripping tower and the inlet of the condenser.

2. The slurry stripping heat recovery system according to claim 1, characterized in that: The heat exchange area of ​​the second heat exchanger is 30m².

3. The slurry stripping heat recovery system according to claim 1, characterized in that: The second heat exchanger has a cold desalinated water inlet and a desalinated water outlet.

4. The slurry stripping heat recovery system according to claim 3, characterized in that: It also includes a soda-water mixer, a hot desalted water tank and a polymerization kettle connected in sequence; The steam-water mixer has a steam inlet and a desalted water inlet; the desalted water inlet of the steam-water mixer is connected to the desalted water outlet of the second heat exchanger.

5. The slurry stripping heat recovery system according to claim 1, characterized in that: The first heat exchanger is a spiral plate heat exchanger.

6. The slurry stripping heat recovery system according to claim 1, characterized in that: The heat exchange area of ​​the first heat exchanger is 120m².

7. The slurry stripping heat recovery system according to claim 1, characterized in that: A feeding tank is also included, and the cold slurry inlet of the stripping tower is connected to the outlet of the feeding tank.

8. The slurry stripping heat recovery system according to claim 1, characterized in that: The hot slurry outlet of the stripping tower is connected with a dry mixing tank.

9. The slurry stripping heat recovery system according to any one of claims 1 to 8, characterized in that: It also includes a gas-liquid separation component, and the feed end of the gas-liquid separation component is connected to the discharge port of the condenser.

10. The slurry stripping heat recovery system according to claim 9, characterized in that: The gas-liquid separation component includes a gas-liquid separation tank, a wastewater tank and a mother night pool; The inlet of the gas-liquid separation tank is connected to the discharge port of the condenser, and the liquid phase outlet of the gas-liquid separation tank is connected to the inlet of the wastewater tank; the liquid phase outlet of the wastewater tank is connected to the inlet of the mother night pool.

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