Naphthalene evaporator heating system in phthalic anhydride device
By introducing external electric heaters and interlocking systems into the phthalenol anhydride device, the problem of insufficient starting and coping capabilities of naphthalene evaporators when there is a lack of external steam pipelines is solved, and the flexibility and stability of the device are improved, energy consumption is reduced and operational safety is ensured.
Patent Information
- Application Number
- CN202520381880.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2035-03-06
AI Technical Summary
In the absence of an external steam network, the existing phthalanhydride device lacks the ability to respond in the initial driving and extreme cases, resulting in reduced device flexibility and stability.
The external electric heater is installed on the basis of the steam heater, and the switching between steam heating and electric heating is achieved through the interlocking system, increasing the reasonable arrangement of the baffle plates to improve the electric heating efficiency.
Ensures stable operation of naphthalene evaporators in driving or extreme situations, improves the flexibility and stability of the device, reduces energy consumption, and avoids the risk of dry burning through temperature interlocking protection.
Smart Images
Figure CN222738502U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of phthalic anhydride devices, and in particular relates to a heating system for a naphthalene evaporator in a phthalic anhydride device. Background Art
[0002] The naphthalene evaporator is one of the key equipment in the naphthalene process phthalic anhydride unit, which is used to achieve a stable supply of naphthalene vapor. The basic process of the naphthalene evaporator is as follows: liquid naphthalene is pumped to the naphthalene evaporator through the tank area, and the naphthalene evaporator heats the liquid naphthalene with an external heat source to heat and vaporize the liquid naphthalene, maintaining a stable liquid level and a stable pressure in the naphthalene evaporator, which can achieve a stable supply of gaseous naphthalene in phthalic anhydride production.
[0003] At present, for naphthalene-based phthalic anhydride enterprises, it is usually necessary to rely on external steam pipelines to meet the initial heating and vaporization needs of the start-up. After the by-product steam of the naphthalene-based phthalic anhydride unit itself is stabilized, the steam supply is switched to the internal pipeline of the unit. However, for enterprises without external steam pipelines, the initial start-up of the naphthalene-based phthalic anhydride unit needs to adopt other energy supply methods, which greatly reduces its flexibility and stability. Utility Model Content
[0004] The utility model aims to overcome the defects of the prior art and provide a heating system for a naphthalene evaporator in a phthalic anhydride device. An external electric heater is provided on the basis of a steam heater to ensure the coping ability of the naphthalene evaporator during start-up or in extreme situations. At the same time, the models of the baffles are reasonably arranged to improve the heating efficiency of the electric heater. At the same time, an interlocking system of steam heating and electric heating is added to achieve rapid response and stable operation of the device.
[0005] The utility model discloses a naphthalene evaporator heating system in a phthalic anhydride device, comprising a liquid naphthalene storage tank, which is connected to a liquid naphthalene pump, which is connected to the bottom of the naphthalene evaporator through a liquid naphthalene flowmeter and a liquid naphthalene flow regulating valve, a pipeline connected to a feed port at the bottom of an electric heater is arranged at the bottom of the naphthalene evaporator, a pipeline refluxed to the naphthalene evaporator is arranged at a discharge port at the top of the electric heater, a steam heater is arranged inside the naphthalene evaporator, the steam heater is connected to a steam pipe network, and a pipeline connected to a condensed water pipe network is arranged at the bottom of a steam generator.
[0006] Preferably, a liquid level gauge and a pressure gauge are provided on the top of the naphthalene evaporator, and a pipeline connected to the oxidation unit is provided on the top of the naphthalene evaporator.
[0007] Preferably, the electric heater comprises an external shell and an internal heating tube bundle, the heating tube bundle is fixed by a baffle, the heating tube bundle is connected to the heating switch on the external shell, removable filters are provided at the bottom feed port and the top discharge port of the electric heater, and a thermometer is provided at the bottom of the heating switch side in the external shell; further, the shell is connected to the internal heating tube bundle through a flange.
[0008] Preferably, the baffles include double-bow baffles and single-bow baffles, and the double-bow baffles and the single-bow baffles are arranged in a cross arrangement: the feed port side and the discharge port side are single-bow baffles, and the double-bow baffle is arranged in the middle.
[0009] Preferably, a pipeline connected to a cleaning pump is provided at the bottom of the electric heater, and a pipeline refluxed to the top of the electric heater is provided at the outlet of the cleaning pump.
[0010] Preferably, the steam heater is a U-tube steam heater, the steam heater is flange-connected to the naphthalene evaporator, and the U-tube bundle on the steam heater is fixed by a baffle.
[0011] Specifically, the working process of the heating system of the naphthalene evaporator in the phthalic anhydride device is as follows: when switching between the steam heater and the electric heater, it is realized through the interlocking system configured in the system. The naphthalene evaporator is provided with an external circulation electric heating mode and is equipped with a naphthalene circulation pump. The liquid naphthalene in the liquid naphthalene storage tank is transported to the naphthalene evaporator through the liquid naphthalene pump. During the transportation process, the liquid naphthalene is controlled by a liquid naphthalene flowmeter and a liquid naphthalene flow regulating valve. The naphthalene evaporator is provided with a liquid level gauge. When the liquid naphthalene in the naphthalene evaporator reaches the process liquid level, the interlocking system controls the naphthalene circulation pump to start. When the naphthalene circulation pump is started, the electric heater can start heating. The liquid naphthalene passes through a bottom feed port and enters the interior of the electric heater for heating after being filtered. The heated liquid naphthalene is then returned to the naphthalene evaporator. The built-in thermometer of the electric heater sets a high-temperature interlocking program through the control system. When the interlocking temperature is reached, the power supply of the electric heater is automatically cut off to prevent dry burning. The gaseous naphthalene is transported to the oxidation unit through a pipeline. When the oxidation reaction is stably exothermic and the by-product steam can meet the steam demand of the naphthalene evaporator, the naphthalene evaporator is switched to 5.0MPa steam of the inner pipe network, the steam heater starts to work, the use of the electric heater is stopped, the naphthalene circulation pump is stopped, the valve on the pipeline is closed, and the external circulation system is disconnected. When the steam heater fails or there is insufficient steam, the interlocking system controls the electric heating to switch at any time according to the pressure display on the naphthalene evaporator to ensure the stability of the device operation.
[0012] The main body of the electric heater equipment is divided into two parts: a shell and a heating tube bundle. The two parts are connected by a flange to facilitate the extraction and maintenance of the heating tube bundle. A plurality of baffles are arranged at the heating tube bundle, including double-bow baffles and single-bow baffles. The double-bow baffles and the single-bow baffles are arranged in a cross arrangement: the feed port side and the discharge port side are single-bow baffles, and double-bow baffles are arranged in the middle. In addition to fixing the tube bundle, the baffles also have an important function of changing the flow direction of liquid naphthalene and increasing the flow path of liquid naphthalene. At the same time, double-bow baffles are introduced into the single-bow baffle to overcome the defects of dead zone and large resistance caused by the turning of the single-bow baffle, and to strengthen the heat exchange between naphthalene and the heating tube bundle. When simple cleaning cannot achieve the maintenance of the heating tube bundle, detergent can be added without disassembly, and the internal detergent circulation can be conveyed by a cleaning pump, and the temperature can be turned on for deep cleaning to ensure the heating efficiency of the electric heater.
[0013] Compared with the prior art, the utility model has the following beneficial effects: the naphthalene evaporator heating system in the phthalic anhydride device of the utility model integrates two modes, electric heating and steam heating. The initial startup relies on electric heating, and it automatically switches to by-product steam heating after the oxidation reaction is stable. Seamless switching is achieved through the interlocking system, which reduces energy consumption and ensures continuity. The electric heater has built-in temperature interlock protection, which automatically cuts off the power when over-temperature occurs, avoids the risk of dry burning, and ensures safe operation. At the same time, in the electric heater, double-bow and single-bow baffles are cross-arranged to extend the flow path of liquid naphthalene and enhance the turbulent heat exchange efficiency. Removable filters are set at the inlet and outlet to intercept impurities, and a cleaning pump is equipped to achieve deep cleaning without disassembly, thereby reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a structural schematic diagram of a heating system for a naphthalene evaporator in a phthalic anhydride device according to the utility model;
[0015] Figure 2 It is a structural schematic diagram of an electric heater in a heating system of a naphthalene evaporator in a phthalic anhydride device according to the utility model;
[0016] Figure 3 This is a schematic diagram of the structure of the double-arcuate baffles described in the utility model;
[0017] Figure 4 It is a structural schematic diagram of the single arched baffle described in the utility model.
[0018] In the figure: 1. naphthalene evaporator; 2. liquid naphthalene storage tank; 3. electric heater; 301. shell; 302. thermometer; 303. heating switch; 304. feed inlet; 305. discharge outlet; 306. heating tube bundle; 307. single bow baffle; 308. double bow baffle; 4. liquid naphthalene pump; 5. liquid naphthalene flow meter; 6. liquid naphthalene flow regulating valve; 7. naphthalene circulation pump; 8. liquid level meter; 9. pressure gauge; 10. oxidation unit; 11. condensate pipe network; 12. steam pipe network; 13. steam heater; 14. cleaning pump. DETAILED DESCRIPTION
[0019] The specific scheme of the utility model is further explained below in conjunction with the accompanying drawings.
[0020] like Figure 1-Figure 4 As shown, a naphthalene evaporator heating system in a phthalic anhydride device comprises a naphthalene evaporator 1, a liquid naphthalene storage tank 2, and an electric heater 3, wherein a pipeline connected to the liquid naphthalene storage tank 2 is provided at the bottom of the naphthalene evaporator 1, a steam heater 13 is provided inside the naphthalene evaporator 1, the naphthalene evaporator 1 is connected to a feed port 304 at the bottom of the electric heater 3 through a naphthalene circulating pump 7, and a discharge port 305 at the top of the electric heater 3 is provided with a pipeline that flows back to the naphthalene evaporator 1; a liquid naphthalene pump 4, a liquid naphthalene flowmeter 5, and a liquid naphthalene flow regulating valve 6 are provided on the pipeline connected to the liquid naphthalene storage tank 2 at the bottom of the naphthalene evaporator 1; a liquid level gauge 8 and a pressure gauge 9 are provided at the top of the naphthalene evaporator 1, and a pipeline connected to an oxidation unit 10 is provided at the top of the naphthalene evaporator 1.
[0021] The electric heater 3 includes an external shell 301 and an internal heating tube bundle 306, the heating tube bundle 306 is fixed by a baffle, the heating tube bundle 306 is connected to the heating switch 303 on the shell 301, and a detachable filter is provided at the bottom feed port 304 and the top discharge port 305 of the electric heater 3, and a thermometer 302 is provided at the bottom of the shell 301 on the side of the heating switch 303; the baffle includes a double-bow baffle 308 and a single-bow baffle 307, and the double-bow baffle 308 and the single-bow baffle 307 are arranged in a cross arrangement: the feed port 304 side and the discharge port 305 side are single-bow baffles 307, and a double-bow baffle 308 is provided in the middle position.
[0022] A pipeline connected to the cleaning pump 14 is arranged at the bottom of the electric heater 3 , and a pipeline refluxed to the top of the electric heater 3 is arranged at the outlet of the cleaning pump 14 .
[0023] The steam heater 13 is a U-shaped tube steam heater, which is connected to the naphthalene evaporator 1 by a flange, and the U-shaped tube bundle on the steam heater 13 is fixed by a baffle.
[0024] The steam heater 13 is connected to the steam network 12 , and the steam heater 13 is provided with a pipeline connected to the condensate network 11 .
[0025] The working process of the naphthalene evaporator heating system in the phthalic anhydride device is as follows: the naphthalene evaporator 1 is set in an external circulation electric heating mode and is equipped with a naphthalene circulating pump 7; the liquid naphthalene in the liquid naphthalene storage tank 2 is transported to the naphthalene evaporator 1 via a liquid naphthalene pump 4; during the transport process, the liquid naphthalene is controlled by a liquid naphthalene flow meter 5 and a liquid naphthalene flow regulating valve 6; the naphthalene evaporator 1 is equipped with a liquid level meter 8; when the liquid naphthalene in the naphthalene evaporator 1 reaches the process liquid level, the interlocking system controls the naphthalene circulating pump 7 to be turned on; when the naphthalene circulating pump 7 is turned on, the electric heater 3 can start heating; the liquid naphthalene passes through a bottom feed port 304, enters the inside of the electric heater 3 after being filtered, and is heated; after heating, the liquid naphthalene returns to the naphthalene evaporator 1; the electric heater 3 starts heating; and the liquid naphthalene passes through a bottom feed port 304, enters the inside of the electric heater 3 after being filtered, and returns to the naphthalene evaporator 1; and the electric heater 3 starts heating. The built-in thermometer 302 sets a high-temperature interlocking program through the control system. When the interlocking temperature is reached, the power supply of the electric heater 3 (heating switch 303) is automatically cut off to prevent dry burning; the gaseous naphthalene is sent to the oxidation unit 10 through the pipeline. When the oxidation reaction is stably exothermic and the by-product steam can meet the steam demand of the naphthalene evaporator 1, the naphthalene evaporator 1 switches to the internal pipe network 5.0MPa steam (from the steam pipe network 12), the steam heater 13 starts to work, the use of the electric heater 3 is stopped, the naphthalene circulation pump 7 is stopped, the valve on the pipeline is closed, the external circulation system is disconnected, and the condensed water generated by the steam heat exchange enters the condensed water pipe network 11 through the pipeline. When the steam heater 13 fails or the steam is insufficient, according to the pressure gauge 9 on the naphthalene evaporator 1, the interlocking system controls the electric heater 3 to switch at any time to ensure the stability of the device operation.
[0026] The main body of the electric heater 3 is divided into two parts: a shell 301 and a heating tube bundle 306. The two parts are connected by a flange to facilitate the extraction and maintenance of the heating tube bundle 306. The heating tube bundle 306 is provided with multiple groups of baffles, including double-bow baffles 308 and single-bow baffles 307. The double-bow baffles 308 and the single-bow baffles 307 are arranged in a cross arrangement: the side of the feed port 304 and the side of the discharge port 305 are single-bow baffles 307, and the middle position is provided with double-bow baffles 308; in addition to fixing the heating tube bundle 30 6, another important function is to change the flow direction of the liquid naphthalene, increase the flow path of the liquid naphthalene, and introduce the double-bowed baffle 308 into the single-bowed baffle 307, so as to overcome the defects of the dead zone and large resistance caused by the turning of the single-bowed baffle 307, and strengthen the heat exchange between the naphthalene and the heating tube bundle 306; when the maintenance of the heating tube bundle 306 cannot be achieved by simple cleaning, the cleaning agent can be added without disassembly, and the internal cleaning agent can be circulated by the cleaning pump 14, and the temperature can be turned on for deep cleaning to ensure the heating efficiency of the electric heater 3.
Claims
1. A naphthalene evaporator heating system in a phthalic anhydride device, characterized in that: The invention comprises a naphthalene evaporator (1), a liquid naphthalene storage tank (2), and an electric heater (3). A pipeline connected to the liquid naphthalene storage tank (2) is arranged at the bottom of the naphthalene evaporator (1). A steam heater (13) is arranged inside the naphthalene evaporator (1). The naphthalene evaporator (1) is connected to a bottom feed port (304) of the electric heater (3) via a naphthalene circulation pump (7). A pipeline refluxed to the naphthalene evaporator (1) is arranged at a top discharge port (305) of the electric heater (3).
2. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 1, characterized in that: A liquid naphthalene pump (4), a liquid naphthalene flow meter (5), and a liquid naphthalene flow regulating valve (6) are provided on the pipeline connecting the bottom of the naphthalene evaporator (1) and the liquid naphthalene storage tank (2).
3. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 1, characterized in that A liquid level gauge (8) and a pressure gauge (9) are arranged on the top of the naphthalene evaporator (1), and a pipeline connected to the oxidation unit (10) is arranged on the top of the naphthalene evaporator (1).
4. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 1, characterized in that The electric heater (3) comprises an external shell (301) and an internal heating tube bundle (306); the heating tube bundle (306) is fixed by a baffle; the heating tube bundle (306) is connected to a heating switch (303) on the shell (301); a detachable filter is provided at a bottom feed port (304) and a top discharge port (305) of the electric heater (3); and a thermometer (302) is provided at the bottom of the shell (301) on the side of the heating switch (303).
5. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 4, characterized in that, The baffles include double-bowed baffles (308) and single-bowed baffles (307), and the double-bowed baffles (308) and the single-bowed baffles (307) are arranged in a cross arrangement: the single-bowed baffles (307) are arranged on the sides of the feed port (304) and the discharge port (305), and the double-bowed baffles (308) are arranged in the middle.
6. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 1, characterized in that: A pipeline connected to a cleaning pump (14) is provided at the bottom of the electric heater (3), and a pipeline that flows back to the top of the electric heater (3) is provided at the outlet of the cleaning pump (14).
7. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 1, characterized in that: The steam heater (13) is a U-shaped tube steam heater. The steam heater (13) is connected to the naphthalene evaporator (1) by a flange. The U-shaped tube bundle on the steam heater (13) is fixed by a baffle.
8. The naphthalene evaporator heating system in the phthalic anhydride device according to claim 1, characterized in that, The steam heater (13) is connected to the steam network (12), and the steam heater (13) is provided with a pipeline connected to the condensate network (11).