Steam waste heat recovery device

Abstract

The utility model belongs to the waste heat utilization technical field of alkylation device, especially relate to a steam waste heat recovery device, including deisobutanizer feed heat exchanger, sulfuric acid cracking device, alkali washing system, de-n-butane column and alkali washing heat exchanger, the steam export of sulfuric acid cracking device and deisobutanizer feed heat exchanger's hot medium import intercommunication, its hot medium export and sulfuric acid cracking device's backwater import intercommunication, alkali washing system effluent export and deisobutanizer feed heat exchanger cold medium import intercommunication, its cold medium export and deisobutanizer column intercommunication, de-n-butane column bottom export and alkali washing heat exchanger hot medium import intercommunication, alkali washing system circulating lye export and alkali washing heat exchanger cold medium import intercommunication, alkali washing heat exchanger cold medium export and alkali washing system circulating lye import intercommunication. The device steam waste heat recovery device reduces water resource and energy loss, improves deisobutanizer feed temperature to reduce its load, and guarantees winter alkali washing effect and device stable operation.

Description

TECHNICAL FIELD

[0001] The present utility model relates to the technical field of waste heat utilization of alkylation units, and specifically to a steam waste heat recovery device. BACKGROUND ART

[0002] In the traditional operation process of an alkylation unit, the working logic of the deisobutanizer feed heat exchanger is as follows: the caustic wash effluent from the caustic wash system first enters the deisobutanizer feed heat exchanger to complete a heat exchange process with the alkylate oil. The core function of this step is to increase the feed temperature of the deisobutanizer through heat exchange, and simultaneously reduce the outlet temperature of the alkylate oil. The cooled alkylate oil is then continuously conveyed to the circulating caustic solution heat exchanger to provide heat for the circulating caustic solution in the caustic wash system. However, this process exposes obvious shortcomings in winter: due to the significant drop in ambient temperature, the heat loss of the circulating caustic solution during transmission and heat exchange increases remarkably, which directly makes it difficult to maintain the temperature of the caustic wash water in the desired range, further weakens the reaction efficiency of the caustic wash step, and affects the stability of the overall purification effect.

[0003] At the same time, the sulfuric acid cracking unit supporting the alkylation unit continuously generates a large amount of steam in the cracking section, and such steam is often directly discharged to the outside in the existing process. This treatment method not only causes unnecessary waste of water resources, but also leads to the failure of effective utilization of a large amount of heat energy contained in the steam, resulting in significant energy loss. From the perspective of energy conservation and process optimization, this steam direct discharge mode not only fails to conform to the concept of sustainable development, but also reduces the energy utilization efficiency of the entire unit, leaving much room for improvement. CONTENTS OF THE UTILITY MODEL

[0004] The purpose of the present utility model is to provide a steam waste heat recovery device, so as to solve the problems proposed in the above BACKGROUND ART.

[0005] To achieve the above purpose, the present utility model provides the following technical solution: A steam waste heat recovery device, comprising a deisobutanizer feed heat exchanger, a sulfuric acid cracking unit, a caustic wash system, a debutanizer, and a caustic wash heat exchanger, wherein a steam outlet of the sulfuric acid cracking unit is in communication with a hot medium inlet of the deisobutanizer feed heat exchanger, and a hot medium outlet of the deisobutanizer feed heat exchanger is in communication with a backwater inlet of the sulfuric acid cracking unit; an effluent outlet of the caustic wash system is in communication with a cold medium inlet of the deisobutanizer feed heat exchanger, and a cold medium outlet of the deisobutanizer feed heat exchanger is in communication with the deisobutanizer; a tower bottom outlet of the debutanizer is in communication with a hot medium inlet of the caustic wash heat exchanger, and a hot medium outlet of the caustic wash heat exchanger is in communication with a subsequent processing unit; a circulating caustic solution outlet of the caustic wash system is in communication with a cold medium inlet of the caustic wash heat exchanger, and a cold medium outlet of the caustic wash heat exchanger is in communication with a circulating caustic solution inlet of the caustic wash system.

[0006] Preferably, the deisobutane tower feed heat exchanger is capable of heat exchange between the steam from the sulfuric acid cracking unit and the effluent from the alkali washing system.

[0007] Preferably, the alkaline washing heat exchanger is capable of heat exchange between the hot material from the bottom of the n-butane removal tower and the circulating alkaline solution of the alkaline washing system.

[0008] Preferably, the condensate formed after the steam generated by the sulfuric acid cracking unit is cooled in the feed heat exchanger of the isobutane removal tower is returned to the sulfuric acid cracking unit through a pipeline for reuse.

[0009] Preferably, the effluent from the self-alkali washing system is heated in the feed heat exchanger of the isobutane removal tower before entering the isobutane removal tower.

[0010] Preferably, a flow control valve is provided on the connecting pipeline between the sulfuric acid cracking unit and the feed heat exchanger of the isobutane removal tower to regulate the steam delivery rate.

[0011] Preferably, a temperature sensor is installed on the pipeline between the cold medium outlet of the deisobutane tower feed heat exchanger and the deisobutane tower to monitor the temperature of the material entering the deisobutane tower.

[0012] Preferably, a temperature monitoring device is installed on the pipeline between the cold medium outlet of the alkaline washing heat exchanger and the circulating alkaline solution inlet of the alkaline washing system to monitor the temperature of the circulating alkaline solution in real time.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. This steam waste heat recovery device introduces a large amount of steam generated by the sulfuric acid cracking unit into the feed heat exchanger of the isobutane removal tower for heat exchange. The condensate generated after heat exchange is recovered to the sulfuric acid cracking unit for reuse, avoiding the waste of water resources and energy caused by direct steam discharge.

[0015] 2. This steam waste heat recovery device increases the feed temperature of the isobutane removal tower by exchanging heat between steam and the effluent from the alkali washing system, thereby reducing the system load of the isobutane removal tower. Attached Figure Description

[0016] Figure 1 This is a flow chart of the original isobutane removal tower feed heater of this utility model;

[0017] Figure 2 This is a flow chart of the feed heater for the existing isobutane removal tower according to this utility model.

[0018] In the diagram: 1. Isobutane removal tower, 2. n-Butane removal tower, 3. Alkali washing system, 4. Alkali washing heat exchanger, 5. Sulfuric acid cracking unit, 6. Isobutane removal tower feed heat exchanger. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Please see Figures 1-2 This utility model provides a technical solution: a steam waste heat recovery device, including an isobutane removal tower feed heat exchanger 6, a sulfuric acid cracking unit 5, an alkaline washing system 3, a n-butane removal tower 2, and an alkaline washing heat exchanger 4. The steam outlet of the sulfuric acid cracking unit 5 is connected to the hot medium inlet of the isobutane removal tower feed heat exchanger 6, and the hot medium outlet of the isobutane removal tower feed heat exchanger 6 is connected to the return water inlet of the sulfuric acid cracking unit 5. The effluent outlet of the alkaline washing system 3 is connected to the cold medium inlet of the isobutane removal tower feed heat exchanger 6. The cold medium outlet of the feed heat exchanger 6 of the isobutane removal tower is connected to the isobutane removal tower 1; the bottom outlet of the n-butane removal tower 2 is connected to the hot medium inlet of the alkali washing heat exchanger 4, and the hot medium outlet of the alkali washing heat exchanger 4 is connected to the subsequent processing unit; the circulating alkali outlet of the alkali washing system 3 is connected to the cold medium inlet of the alkali washing heat exchanger 4, and the cold medium outlet of the alkali washing heat exchanger 4 is connected to the circulating alkali inlet of the alkali washing system 3. By constructing a closed-loop process with multiple devices linked, the cascade utilization of steam waste heat and material circulation are realized. This not only solves the energy waste problem of direct steam emission from the sulfuric acid cracking unit, but also ensures the temperature stability of the alkali washing system in winter by optimizing the heat exchange path, while reducing the operating load of the isobutane removal tower, thereby improving the overall energy utilization rate and operational stability of the alkylation unit.

[0021] The deisobutane tower feed heat exchanger 6 enables heat exchange between the steam from the sulfuric acid cracking unit 5 and the effluent from the alkaline washing system 3. Through the targeted heat exchange design of the deisobutane tower feed heat exchanger 6, the originally idle steam heat energy is efficiently transferred to the alkaline washing effluent. On the one hand, this avoids the direct loss of steam heat energy, and on the other hand, it increases the initial temperature of the alkaline washing effluent entering the deisobutane tower 1, reducing the energy consumption required for subsequent heating of the deisobutane tower 1, thus achieving a "two-in-one" energy-saving effect.

[0022] The alkaline washing heat exchanger 4 can realize heat exchange between the hot material from the bottom of the n-butane stripping tower 2 and the circulating alkaline solution of the alkaline washing system 3. It uses the residual heat of the hot material at the bottom of the n-butane stripping tower 2 to heat the circulating alkaline solution, replacing the traditional mode of relying on alkylation oil for cooling and heat release. This ensures that the circulating alkaline solution can be maintained at the ideal reaction temperature when the ambient temperature is low in winter, avoiding the decrease in purification effect due to insufficient alkaline washing water temperature, ensuring the stable operation of the alkaline washing system 3, and reducing raw material waste or product quality problems caused by process fluctuations.

[0023] The condensate formed by the cooling of steam generated in the isobutane removal tower feed heat exchanger 6 in the sulfuric acid cracking unit 5 is returned to the sulfuric acid cracking unit 5 through pipelines for reuse. This condensate return design achieves a closed-loop water resource cycle. It avoids water waste caused by direct discharge of condensed steam, while also reducing the amount of fresh water needed for the sulfuric acid cracking unit, lowering water treatment costs and reducing wastewater discharge pressure.

[0024] The effluent from the alkali washing system 3 is heated in the feed heat exchanger 6 of the isobutane removal column before entering the isobutane removal column 1. Increasing the feed temperature of the isobutane removal column 1 reduces the consumption of heating media within the column, thereby lowering the heat load and operating energy consumption of the column. Simultaneously, a stable feed temperature also contributes to improved distillation efficiency within the column, reduces product purity fluctuations caused by temperature variations, and increases the yield of the target product.

[0025] A flow control valve is installed on the connecting pipeline between the sulfuric acid cracking unit 5 and the feed heat exchanger 6 of the isobutane removal tower. This valve is used to regulate the steam supply. Based on real-time parameters such as the feed temperature requirement of the isobutane removal tower 1 and the load of the alkali washing system 3, the flow control valve dynamically adjusts the steam input, preventing excessive steam supply leading to heat energy waste or insufficient supply affecting heat exchange efficiency. This achieves precise "on-demand distribution" control, further optimizing energy utilization efficiency and adapting to the operating requirements of the unit under different conditions.

[0026] A temperature sensor is installed on the pipeline between the cold medium outlet of the feed heat exchanger 6 of the isobutane removal tower and the isobutane removal tower 1. This sensor monitors the temperature of the material entering the isobutane removal tower 1, providing real-time feedback of the feed temperature data. This data informs the adjustment of the flow control valve, forming a closed-loop control system. This ensures that the temperature of the material entering the isobutane removal tower 1 remains stable within the optimal range, avoiding operational fluctuations within the tower due to abnormal temperatures, reducing the probability of rework or defective products, and improving the reliability of the unit's operation.

[0027] A temperature monitoring device is installed on the pipeline between the cold medium outlet of the alkali washing heat exchanger 4 and the circulating alkali inlet of the alkali washing system 3. This device is used to monitor the temperature of the circulating alkali in real time. Real-time monitoring of the circulating alkali temperature can promptly detect problems such as abnormal heat loss or decreased heat exchange efficiency in winter. This allows operators to adjust the flow rate of the bottom hot material of the n-butane removal tower 2 or repair the heat exchanger in a timely manner, ensuring that the alkali temperature always meets the reaction requirements, guaranteeing stable alkali washing effect, and avoiding corrosion of subsequent equipment or product contamination caused by substandard alkali washing.

[0028] Working principle: The sulfuric acid cracking unit 5 generates a large amount of steam in the cracking section. The steam is transported from the steam outlet of the sulfuric acid cracking unit 5 through the pipeline to the heat medium inlet of the deisobutane tower feed heat exchanger 6 and enters the deisobutane tower feed heat exchanger 6.

[0029] The effluent from the alkali washing system 3 is transported through a pipeline from the effluent outlet of the alkali washing system 3 to the cold medium inlet of the feed heat exchanger 6 of the isobutane removal tower, and then enters the feed heat exchanger 6 of the isobutane removal tower.

[0030] In the isobutane removal tower feed heat exchanger 6, steam exchanges heat with the alkaline wash effluent. After the steam cools down, it forms condensate. The condensate is then transported through a pipeline from the heat medium outlet of the isobutane removal tower feed heat exchanger 6 back to the return water inlet of the sulfuric acid cracking unit 5, thus achieving recycling.

[0031] The temperature of the alkaline wash effluent increases after heat exchange, and it is transported through a pipeline from the cold medium outlet of the feed heat exchanger 6 of the isobutane removal tower to the isobutane removal tower 1, thereby increasing the feed temperature of the isobutane removal tower 1.

[0032] The hot material from the bottom of the n-butane removal tower 2 is transported through a pipeline to the hot medium inlet of the alkali washing heat exchanger 4 and enters the alkali washing heat exchanger 4; the circulating alkali solution of the alkali washing system 3 is transported through a pipeline from the circulating alkali solution outlet to the cold medium inlet of the alkali washing heat exchanger 4 and enters the alkali washing heat exchanger 4.

[0033] In the alkaline washing heat exchanger 4, the hot material exchanges heat with the circulating alkaline solution. After the heat exchange, the hot material is transported to the subsequent treatment device through the pipeline from the hot medium outlet of the alkaline washing heat exchanger 4. After the circulating alkaline solution exchanges heat, its temperature rises and it is transported back to the circulating alkaline solution inlet of the alkaline washing system 3 through the pipeline from the cold medium outlet of the alkaline washing heat exchanger 4, thus ensuring the temperature of the circulating alkaline solution in winter and ensuring the alkaline washing effect.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A steam waste heat recovery device, comprising an isobutane removal tower feed heat exchanger (6), a sulfuric acid cracking unit (5), an alkaline washing system (3), a n-butane removal tower (2), and an alkaline washing heat exchanger (4), characterized in that: The steam outlet of the sulfuric acid cracking unit (5) is connected to the hot medium inlet of the feed heat exchanger (6) of the deisobutane tower, and the hot medium outlet of the feed heat exchanger (6) of the deisobutane tower is connected to the return water inlet of the sulfuric acid cracking unit (5); the effluent outlet of the alkaline washing system (3) is connected to the cold medium inlet of the feed heat exchanger (6) of the deisobutane tower, and the cold medium outlet of the feed heat exchanger (6) of the deisobutane tower is connected to the deisobutane tower (1); the bottom outlet of the de-n-butane tower (2) is connected to the hot medium inlet of the alkaline washing heat exchanger (4), and the hot medium outlet of the alkaline washing heat exchanger (4) is connected to the subsequent treatment device; the circulating alkaline outlet of the alkaline washing system (3) is connected to the cold medium inlet of the alkaline washing heat exchanger (4), and the cold medium outlet of the alkaline washing heat exchanger (4) is connected to the circulating alkaline inlet of the alkaline washing system (3).

2. The steam waste heat recovery device according to claim 1, characterized in that: The deisobutane tower feed heat exchanger (6) can realize heat exchange between the steam from the sulfuric acid cracking unit (5) and the effluent from the alkaline washing system (3).

3. The steam waste heat recovery device according to claim 1, characterized in that: The alkaline washing heat exchanger (4) can realize heat exchange between the hot material from the bottom of the n-butane removal tower (2) and the circulating alkaline solution of the alkaline washing system (3).

4. A steam waste heat recovery device according to claim 1, characterized in that: The condensate formed by the steam generated by the sulfuric acid cracking unit (5) after being cooled in the isobutane removal tower feed heat exchanger (6) is returned to the sulfuric acid cracking unit (5) through a pipeline for reuse.

5. A steam waste heat recovery device according to claim 1, characterized in that: The effluent from the alkaline washing system (3) is heated in the feed heat exchanger (6) of the deisobutane tower and then enters the deisobutane tower (1).

6. A steam waste heat recovery device according to claim 1, characterized in that: A flow control valve is provided on the connecting pipe between the sulfuric acid cracking unit (5) and the isobutane removal tower feed heat exchanger (6) to regulate the steam delivery rate.

7. A steam waste heat recovery device according to claim 1, characterized in that: A temperature sensor is installed on the pipeline between the cold medium outlet of the deisobutane tower feed heat exchanger (6) and the deisobutane tower (1) to monitor the temperature of the material entering the deisobutane tower (1).

8. A steam waste heat recovery device according to claim 1, characterized in that: A temperature monitoring device is installed on the pipeline between the cold medium outlet of the alkaline washing heat exchanger (4) and the circulating alkaline solution inlet of the alkaline washing system (3) to monitor the temperature of the circulating alkaline solution in real time.

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