Process method and device for preventing leakage of spiral-plate heat exchanger of slurry reactor

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to a technological method and device for preventing leakage of a slurry reactor spiral-plate heat exchanger, and solves the problem of leakage of the spiral-plate heat exchanger caused by unbalanced pressure by arranging a pressure balancing device and monitoring and accurately controlling the pressure difference of channels on the two sides of the spiral-plate heat exchanger in real time. The stability of the heat exchange process and the production safety are guaranteed, meanwhile, the maintenance cost of the spiral plate heat exchanger is reduced, and the operation cycle of the device is prolonged. According to the invention, the heat load of the heating furnace is also reduced, and the raw oil is preheated by utilizing the waste heat of the hot high-pressure oil of the slurry bed residual oil hydrogenation device, so that the raw oil is heated to a certain extent before entering the heating furnace, the heat load of the raw oil heating furnace is obviously reduced, the fuel consumption of the heating furnace is reduced, and the energy cost is reduced. According to the system, heat exchange between the hot high-pressure oil and the raw oil can be more sufficiently realized, the heat recovery efficiency of the whole system is improved, and the energy utilization efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum chemical industry, in particular to a process method and device for preventing leakage of a slurry bed spiral plate heat exchanger. BACKGROUND

[0002] The slurry bed residual oil hydrogenation technology is a high-temperature and high-pressure reaction of inferior heavy oil / residual oil in the presence of hydrogen and catalyst. The technology has the characteristics of both hydrogenation and thermal processing. Due to its strong adaptability to raw materials and high conversion rate, it has obvious advantages in processing inferior heavy oil. Therefore, in recent years, the slurry bed residual oil hydrogenation technology has received widespread attention at home and abroad. The hot high-pressure oil of the slurry bed residual oil hydrogenation device contains a large amount of residual heat, which is exchanged with deoxygenated water through a spiral plate heat exchanger, so that the heat can be effectively recovered, and the deoxygenated water is connected with a steam drum to circulate and produce steam of a certain pressure grade, which is used inside the device; the spiral plate heat exchanger is often used to reduce the heat of the hot high-pressure oil due to its high heat transfer efficiency, compact structure, and small footprint.

[0003] However, when the spiral plate heat exchanger is used to exchange heat between the hot high-pressure oil and the deoxygenated water, there are some problems. Due to the large difference in properties between the hot high-pressure oil and the deoxygenated water, the pressure, pressure difference, temperature, and other working conditions on both sides of the spiral plate heat exchanger are complex during the heat exchange process, which can easily cause leakage of the spiral plate heat exchanger. Once the leakage occurs, not only the heat exchange efficiency is reduced, but also the deoxygenated water medium may enter the hot high-pressure oil medium, causing an increase in acidic water in the downstream system tower, and a large amount of acidic water not only carries a large amount of coke powder to block the downstream acidic water filter, affecting the stability of the subsequent production process, but also poses a certain safety hazard. In addition, the leakage of the spiral plate heat exchanger increases the maintenance cost and labor cost, and the spiral plate heat exchanger has a long maintenance period, which causes a long-term lack of spare spiral plate heat exchanger, affecting the operation period of the device. Therefore, a new method and system are needed to not only solve the leakage problem of the spiral plate heat exchanger, but also effectively utilize the large amount of residual heat of the hot high-pressure oil. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a process method and device for preventing leakage of a slurry bed spiral plate heat exchanger, which solves the leakage problem of the spiral plate heat exchanger, reduces the heat load of the raw oil heating furnace, improves the heat recovery efficiency, ensures the stability and safety of the production process, and reduces energy consumption.

[0005] The technical solution adopted by the present application to solve its technical problems is: A process method for preventing leakage of a slurry bed spiral plate heat exchanger, comprising: Step 1: Draw out hot high-temperature oil from the hot high-temperature separation system of the slurry bed residue hydrotreating unit. The temperature of the hot high-temperature oil is 350~480℃ and the pressure is 5~24MPa. Reduce the pressure of the hot high-temperature oil to 0.5~5MPa through the pressure reducing valve and transport the hot high-temperature oil to one side channel of the spiral plate heat exchanger. Step 2: Pressurize the raw oil through the pump body and introduce it into the other channel of the spiral plate heat exchanger. The temperature of the raw oil is 100 ~ 350℃ and the pressure is 0.5 ~ 5MPa. Step 3: In the spiral plate heat exchanger, the hot high-temperature oil and the feed oil exchange heat in a countercurrent manner. The hot high-temperature oil transfers heat to the feed oil, causing the temperature of the feed oil to rise and the temperature of the hot high-temperature oil to drop. Step 4: By using a pressure balancing device installed outside the spiral plate heat exchanger, the pressure and pressure difference in the channels on both sides of the heat exchanger are monitored in real time. By adjusting the amount of hot high-temperature oil and the amount of raw oil, as well as the temperature control valve of the raw oil, the pressure difference in the channels on both sides of the spiral plate heat exchanger is kept within the preset range to prevent leakage of the spiral plate heat exchanger. Step 5: After heat exchange in the spiral plate heat exchanger, the raw oil enters the raw oil heating furnace for further heating. Since some heat is recovered from the hot oil, the heat load of the raw oil heating furnace is reduced, thus saving fuel gas consumption and reducing fuel gas usage costs. Step 6: The hot high-temperature oil after heat exchange enters the slurry fractionation system, and the feed oil heated by the heating furnace enters the mixing feed tank system.

[0006] Furthermore, in step 1, the hot high-pressure oil is depressurized to 1-3 MPa through a pressure reducing valve.

[0007] Furthermore, in step 4, the pressure difference within the channels on both sides of the spiral plate heat exchanger is maintained within 0.5 MPa.

[0008] Furthermore, steps 1 and 2 are executed simultaneously, or steps 1 are executed first and then steps 2, or steps 2 are executed first and then steps 1.

[0009] An apparatus for preventing leakage in a slurry-bed spiral plate heat exchanger includes a thermal high-resolution system of a slurry-bed residue oil hydrotreating unit, a spiral plate heat exchanger, a feedstock oil heater, and a pressure balancing device. The thermal high-resolution system is connected to one side inlet of the spiral plate heat exchanger via a pipe equipped with a pressure-reducing valve, for conveying the thermal high-resolution oil to the spiral plate heat exchanger. The feedstock tank is connected to the other side inlet of the spiral plate heat exchanger via a feedstock oil conveying pipe, for introducing feedstock oil into the spiral plate heat exchanger. One side outlet of the spiral plate heat exchanger is connected to downstream processing equipment for the thermal high-resolution oil (such as a slurry distillation system) via a pipe, and the other side outlet is connected to the inlet of the feedstock oil heater via a pipe. A pressure balancing device is installed outside the spiral plate heat exchanger to detect the spiral plate pressure and pressure differential.

[0010] Furthermore, the heating furnace is connected to the mixing feed tank system via pipes.

[0011] Furthermore, the pressure balancing device includes a pressure sensor, a controller, and a pressure regulating valve; a pressure sensor is installed on each of the two channels of the spiral plate heat exchanger to monitor the pressure in the two channels in real time and transmit the pressure signal to the controller; the controller analyzes and processes the received pressure signal and can send instructions to the pressure regulating valve; the pressure regulating valve is installed on the pipeline for conveying hot high-temperature oil or raw material oil, and adjusts the flow rate of the fluid in the pipeline according to the instructions of the controller, thereby adjusting the pressure in the two channels and keeping the pressure difference within a set range.

[0012] Furthermore, the mixing feed tank system is connected to the reactor via pump body two, and the reactor is connected to the thermal high-resolution system of the slurry bed residue oil hydrotreating unit.

[0013] Furthermore, a pump body is installed on the raw oil conveying pipeline.

[0014] Technical effects of the present invention: Compared with existing technologies, this invention, by setting up a pressure balancing device, monitors and precisely controls the pressure difference between the two channels of the spiral plate heat exchanger in real time, reducing the risk of leakage caused by pressure imbalance, ensuring the stability of the heat exchange process and the safety of production, avoiding the adverse effects of oil mixing on subsequent processes, and reducing the maintenance and labor costs of the spiral plate heat exchanger, while extending the operating cycle of the unit. This invention also reduces the heat load of the heating furnace by utilizing the waste heat of the hot high-efficiency oil from the slurry bed residue oil hydrotreating unit to preheat the feedstock oil, ensuring the feedstock oil receives a certain temperature rise before entering the heating furnace, significantly reducing the heat load of the feedstock oil heating furnace, reducing fuel consumption, lowering energy costs, and meeting the development requirements of energy conservation and emission reduction. This invention improves heat recovery efficiency. The spiral plate heat exchanger itself has high heat transfer efficiency; combined with the method and device of this invention, it can more fully realize the heat exchange between the hot high-efficiency oil and the feedstock oil, improving the heat recovery efficiency of the entire system and enhancing energy utilization efficiency. The device structure of this invention is rationally designed, easy to install and implement in existing production units, and has good application value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structural principle of the device for preventing leakage in a slurry bed spiral plate heat exchanger according to the present invention.

[0016] In the diagram, 1. Slurry bed residue oil hydrogenation unit thermal high-temperature separation system; 2. Spiral plate heat exchanger; 3. Pump body one; 4. Pump body two; 5. Feed tank; 6. Feed oil conveying pipeline; 7. Slurry distillation system; 8. Heating furnace; 9. Mixing feed tank system; 10. Reactor. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0018] Example 1: like Figure 1 As shown, this embodiment relates to a process method for preventing leakage in a slurry bed spiral plate heat exchanger 2, comprising: Step 1: Draw hot high-temperature oil from the hot high-temperature separation system of the slurry bed residue oil hydrotreating unit. The temperature of the hot high-temperature oil is 350~480℃ and the pressure is 5~24MPa. Reduce the pressure of the hot high-temperature oil to 0.5~5MPa through the pressure reducing valve and transport the hot high-temperature oil to one side channel of the spiral plate heat exchanger 2. Step 2: Pressurize the raw oil through pump body 3 and introduce it into the other channel of spiral plate heat exchanger 2. The temperature of the raw oil is 100 ~ 350℃ and the pressure is 0.5 ~ 5MPa. Step 3: In the spiral plate heat exchanger 2, the hot high-temperature oil and the raw material oil exchange heat in a countercurrent manner. The hot high-temperature oil transfers heat to the raw material oil, causing the temperature of the raw material oil to rise and the temperature of the hot high-temperature oil to drop. Step 4: By using a pressure balancing device installed outside the spiral plate heat exchanger 2, the pressure and pressure difference in the channels on both sides of the heat exchanger are monitored in real time. By adjusting the amount of hot high-temperature oil and the amount of raw oil, as well as the temperature control valve of the raw oil, the pressure difference in the channels on both sides of the spiral plate heat exchanger 2 is kept within 0.5MPa to prevent leakage of the spiral plate heat exchanger 2. Step 5: After heat exchange in the spiral plate heat exchanger 2, the raw oil enters the raw oil heating furnace 3 for further heating. Since some heat is recovered from the hot oil, the heat load of the raw oil heating furnace 3 is reduced; thus saving fuel gas consumption in the heating furnace 8 and reducing fuel gas usage costs. Step 6: The hot high-temperature oil after heat exchange enters the slurry fractionation system, and the raw material oil heated by the heating furnace 8 enters the mixing feed tank system 9.

[0019] Example 2: This embodiment relates to an apparatus for implementing the process method described in Embodiment 1 for preventing leakage in a slurry bed spiral plate heat exchanger. For example... Figure 1 As shown, the apparatus includes a slurry bed residue oil hydrotreating unit thermal high-efficiency separation system 1, a spiral plate heat exchanger 2, a feedstock oil heater 8, and a pressure balancing device. The slurry bed residue oil hydrotreating unit thermal high-efficiency separation system 1 is connected to one side inlet of the spiral plate heat exchanger 2 via a pipeline equipped with a pressure reducing valve, for conveying the thermal high-efficiency separation oil to the spiral plate heat exchanger 2. The feedstock tank 5 is connected to the other side inlet of the spiral plate heat exchanger 2 via a feedstock oil conveying pipeline 6, and a pump body 3 is installed on the feedstock oil conveying pipeline 6 for introducing the feedstock oil into the spiral plate heat exchanger 2. One side outlet of the spiral plate heat exchanger 2 is connected to a slurry distillation system 7 via a pipeline, and the other side outlet is connected to the inlet of the feedstock oil heater 8 via a pipeline. The heater 8 is connected to a mixing feed tank system 9 via a pipeline. The mixing feed tank system 9 is connected to a reactor 10 via a second pump body 4, and the reactor 10 is connected to the slurry bed residue oil hydrotreating unit thermal high-efficiency separation system 1. A pressure balancing device for detecting the spiral plate pressure and pressure difference is installed outside the spiral plate heat exchanger 2.

[0020] The pressure balancing device includes a pressure sensor, a controller, and a pressure regulating valve. A pressure sensor is installed on each of the two channels of the spiral plate heat exchanger 2 to monitor the pressure in the two channels in real time and transmit the pressure signal to the controller. The controller analyzes and processes the received pressure signal, and when the pressure difference between the two channels exceeds 0.5 MPa, it sends a command to the pressure regulating valve. The pressure regulating valve is installed on the pipeline for conveying hot high-temperature oil or raw material oil, and adjusts the flow rate of the fluid in the pipeline according to the controller's command, thereby adjusting the pressure in the two channels to maintain the pressure difference within a set range.

[0021] Example 3: In this embodiment, in the slurry bed residue hydrotreating unit, the hot high-temperature oil drawn from reactor 10 has a temperature of 390~415℃ and a pressure of 15~16MPa. The pressure is reduced to 1.5~2.5MPa via a pressure reducing valve and then transported to one side of the spiral plate heat exchanger 2. The feed oil has a temperature of 200~250℃ and a pressure of 3.0~3.5MPa and is introduced into the other side of the spiral plate heat exchanger 2. A pressure balancing device is installed outside the spiral plate heat exchanger 2. Two pressure sensors in the pressure balancing device monitor the pressure on both sides of the channel in real time. When the pressure difference exceeds 0.5MPa, the controller controls the pressure regulating valve to adjust the flow rate of the hot high-temperature oil delivery pipeline, keeping the pressure difference within 0.5MPa. After heat exchange, the temperature of the raw oil rises to 240-270°C and then enters the raw oil heating furnace 8. Compared with the method of this invention, the heat load of the raw oil heating furnace 8 is reduced by 20-30%. Moreover, during continuous operation for 3-6 months, the spiral plate heat exchanger 2 did not leak, the heat recovery efficiency was significantly improved, and the production cost was effectively reduced.

[0022] The above-described specific embodiments are merely specific examples of the present invention. The patent protection scope of the present invention includes, but is not limited to, the above-described specific embodiments. Any appropriate changes or modifications made by a person skilled in the art that conform to the claims of the present invention should fall within the patent protection scope of the present invention.

Claims

1. A process method for preventing leakage in a slurry bed spiral plate heat exchanger, characterized in that, include: Step 1: Draw out hot high-temperature oil from the hot high-temperature separation system of the slurry bed residue oil hydrotreating unit. The temperature of the hot high-temperature oil is 350~480℃ and the pressure is 5~24MPa. Reduce the pressure of the hot high-temperature oil to 0.5~5MPa through the pressure reducing valve and transport the hot high-temperature oil to one side channel of the spiral plate heat exchanger. Step 2: Pressurize the raw oil through the pump body and introduce it into the other channel of the spiral plate heat exchanger. The temperature of the raw oil is 100 ~ 350℃ and the pressure is 0.5 ~ 5MPa. Step 3: In the spiral plate heat exchanger, the hot high-temperature oil and the feed oil exchange heat in a countercurrent manner. The hot high-temperature oil transfers heat to the feed oil, causing the temperature of the feed oil to rise and the temperature of the hot high-temperature oil to drop. Step 4: By using a pressure balancing device installed outside the spiral plate heat exchanger, the pressure and pressure difference in the channels on both sides of the heat exchanger are monitored in real time. By adjusting the amount of hot high-temperature oil and the amount of raw oil, as well as the temperature control valve of the raw oil, the pressure difference in the channels on both sides of the spiral plate heat exchanger is kept within the preset range to prevent leakage of the spiral plate heat exchanger. Step 5: After heat exchange in the spiral plate heat exchanger, the raw oil enters the raw oil heating furnace for further heating. Since some heat is recovered from the hot oil, the heat load of the raw oil heating furnace is reduced, thus saving fuel gas consumption and reducing fuel gas usage costs. Step 6: The hot high-temperature oil after heat exchange enters the slurry fractionation system, and the feed oil heated by the heating furnace enters the mixing feed tank system.

2. The process method for preventing leakage in a slurry bed spiral plate heat exchanger according to claim 1, characterized in that, In step 1, the hot high-pressure oil is depressurized to 1-3 MPa through a pressure reducing valve.

3. The process method for preventing leakage in a slurry bed spiral plate heat exchanger according to claim 1, characterized in that, In step 4, the pressure difference between the two sides of the spiral plate heat exchanger is maintained within 0.5 MPa.

4. The process method for preventing leakage in a slurry bed spiral plate heat exchanger according to claim 1, characterized in that, Step 1 and Step 2 may be executed simultaneously, or Step 1 may be executed first and then Step 2, or Step 2 may be executed first and then Step 1.

5. An apparatus for implementing the process method as described in any one of claims 1-4, characterized in that, The apparatus includes a slurry bed residue hydrotreating unit with a thermal high-resolution system, a spiral plate heat exchanger, a feedstock oil heater, and a pressure balancing device. The thermal high-resolution system of the slurry bed residue hydrotreating unit is connected to one side inlet of the spiral plate heat exchanger via a pipeline equipped with a pressure reducing valve. The feedstock tank is connected to the other side inlet of the spiral plate heat exchanger via a feedstock oil delivery pipeline. One side outlet of the spiral plate heat exchanger is connected to downstream processing equipment for the thermal high-resolution oil via a pipeline, and the other side outlet is connected to the inlet of the feedstock oil heater via a pipeline. A pressure balancing device is installed outside the spiral plate heat exchanger to detect the spiral plate pressure and pressure difference.

6. The apparatus according to claim 5, characterized in that, The heating furnace is connected to the mixing and feeding tank system via pipes.

7. The apparatus according to claim 5, characterized in that, The pressure balancing device includes a pressure sensor, a controller, and a pressure regulating valve. A pressure sensor is installed on each of the two channels of the spiral plate heat exchanger to monitor the pressure in the two channels in real time and transmit the pressure signal to the controller. The controller analyzes and processes the received pressure signal and can send instructions to the pressure regulating valve. The pressure regulating valve is installed on the pipeline for conveying hot high-temperature oil or raw material oil. According to the instructions of the controller, it adjusts the flow rate of the fluid in the pipeline, thereby adjusting the pressure in the two channels and keeping the pressure difference within a set range.

8. The apparatus according to claim 5, characterized in that, The mixing feed tank system is connected to the reactor via pump body two, and the reactor is connected to the thermal high-resolution system of the slurry bed residue oil hydrotreating unit.

9. The apparatus according to claim 5, characterized in that, A pump body is installed on the raw oil conveying pipeline.

Images