Two-section needle coke production device and method
By adding a raw material preheating furnace to the needle coke production unit, a two-stage preheating system was formed, which solved the impact of coke tower operation on the fractionation tower, achieved temperature stability and improved product quality, and reduced fuel consumption.
Patent Information
- Application Number
- CN202411701067.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2026-05-26
AI Technical Summary
In existing needle coke production facilities, the operation of the coke tower affects the fractionation tower, leading to an imbalance in heat and gas-liquid balance, which in turn affects product quality and yield.
An additional raw material preheating furnace is added to the existing equipment to form a two-stage preheating system. The temperature of the raw material and the flow rate of the fuel gas are controlled by the regulating device to ensure the stability of the distillation tower temperature.
This improved product quality and yield, reduced fuel consumption in the heating furnace, and achieved energy savings and increased production efficiency.
Smart Images
Figure CN122080966A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of petrochemical technology, and in particular to a two-stage needle coke production apparatus and method. Background Technology
[0002] Needle coke is a high-quality artificial graphite material with a series of advantages, including low coefficient of thermal expansion, low porosity, low sulfur, low ash content, low metal content, high electrical conductivity, and easy graphitization. Its graphitized products exhibit good chemical stability, corrosion resistance, high thermal conductivity, good mechanical strength at both low and high temperatures, and excellent overall electrochemical performance. These characteristics make needle coke a superior raw material for manufacturing ultra-high-power graphite electrodes, lithium-ion battery anode materials, and high-end carbon products, giving it special applications and significant importance in both national defense and civilian industries.
[0003] In conventional needle coke production units, the raw material, after heat exchange, enters a fractionation tower, mixes with circulating oil, and is then fed into a heater for heating. Once heated to the reaction temperature, it enters the coking tower for reaction. A crucial aspect of the unit's operation is the preheating and switching of the coking tower. This serves two purposes: first, to prevent the coking tower from heating up too rapidly after a high-temperature feed, which could lead to excessive thermal stress and shorten its lifespan; and second, to prevent the radiant oil from cooling rapidly after switching to a higher-temperature feed, which could lower the reaction temperature and negatively impact liquid yield and the quality of the needle coke product.
[0004] During normal operation, the coke tower preheating process involves drawing high-temperature oil and gas from the coke tower to the preheating tower. However, because a portion of the oil and gas goes to the preheating tower, the feed to the fractionation tower is reduced, disrupting the heat balance of the fractionation tower and causing a drop in the tower bottom temperature. This affects the material balance of the fractionation tower, resulting in a decrease in the yield of liquid products and a reduction in the uniformity of needle coke products. Additionally, the load on the heating furnace increases, leading to an increase in the coking rate of the furnace tubes.
[0005] To reduce the impact of coke tower operation on the fractionation tower and stabilize product quality, it is necessary to improve the raw material preheating methods without affecting the heat exchange network, thereby increasing and stabilizing the temperature entering the fractionation tower. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a two-stage needle coke production apparatus and method to address the shortcomings of the prior art.
[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a two-stage needle coke production device, comprising: a heat exchange device, a raw material preheating furnace, a fractionation tower, and a regulating device, wherein the heat exchange device is connected to the raw material preheating furnace through a pipeline, the raw material preheating furnace is connected to the fractionation tower through a pipeline, and the regulating device is connected to both the raw material preheating furnace and the fractionation tower.
[0008] The beneficial effects of adopting the technical solution of this invention are as follows: Based on the existing raw material heat exchange in the needle coke production unit, an additional raw material preheating furnace is added, forming a two-stage preheating system of "conventional heat exchange + preheating furnace". This added raw material preheating facility increases and stabilizes the temperature at the bottom of the fractionation tower when the operation of the coke tower might affect the fractionation tower, thereby controlling the gas-liquid and heat balance of the fractionation tower. The product indicators of each side stream are unaffected by fluctuations in coke tower operation, resulting in relatively stable yields and product quality for each product. The independent preheating furnace allows the raw material to reach a more precise and higher preset temperature before entering the fractionation tower. This effectively reduces the impact of coke tower operation on the gas-liquid and heat balance of the fractionation tower, thus improving the quality of the unit's products. During coke tower cutting and preheating, the temperature at the bottom of the fractionation tower decreases by approximately 10-25°C. The increase and stabilization of the fractionation tower bottom temperature ensures stable heat distribution in the coke tower during cutting and preheating, and this near-steady-state control significantly improves the uniformity of needle coke product quality. By increasing the temperature of the feedstock before it enters the fractionation tower, fuel consumption in the heating furnace is reduced. For every 10°C increase in feedstock temperature, fuel gas consumption can be reduced by approximately 3%. This achieves energy savings and improved production efficiency to a certain extent.
[0009] Furthermore, the regulating device includes: a first temperature control element, a second temperature control element, a flow control element, and a flow regulating valve. The raw material preheating furnace is connected to fuel gas via a pipeline. The flow regulating valve is installed on the pipeline between the raw material preheating furnace and the fuel gas. The first temperature control element is connected to the pipeline between the raw material preheating furnace and the fractionation tower. The second temperature control element is connected to the fractionation tower. The flow control element is connected to the first temperature control element, the second temperature control element, and the flow regulating valve, respectively.
[0010] The beneficial effects of adopting the above-mentioned further technical solutions are: the setting of the first temperature control element, the second temperature control element, the flow control element and the flow regulating valve facilitates temperature acquisition, analysis and fuel flow regulation, improves automation and accuracy.
[0011] Furthermore, the flow control element is connected to the first temperature control element and the second temperature control element respectively via a temperature selection switch.
[0012] The beneficial effects of adopting the above-mentioned further technical solutions are: the setting of the temperature selection switch facilitates the switching of cascade control mode and improves automation.
[0013] Furthermore, the heat exchange device includes: a feedstock oil / diesel heat exchanger, a feedstock oil / gasoline heat exchanger, and a feedstock oil / wax oil heat exchanger. The feedstock oil / diesel heat exchanger is connected to a feedstock oil self-bound zone. The feedstock oil / diesel heat exchanger is connected to the feedstock oil / gasoline heat exchanger via a pipeline. The feedstock oil / gasoline heat exchanger is connected to the feedstock oil / wax oil heat exchanger via a pipeline. The feedstock oil / wax oil heat exchanger is connected to the feedstock preheating furnace via a pipeline.
[0014] The beneficial effects of adopting the above-mentioned further technical solution are: the feed oil enters the device from the boundary area and exchanges heat with the feed oil diesel heat exchanger, the feed oil gasoline heat exchanger, and the feed oil wax oil heat exchanger according to the temperature difference.
[0015] Furthermore, the fractionation tower is connected to a heating furnace feed pump via a pipeline, and the heating furnace feed pump is connected to a heating furnace via a pipeline.
[0016] The beneficial effect of adopting the above-mentioned further technical solution is that the raw materials are mixed with circulating oil and then sent to the heating furnace for heating through the heating furnace feed pump.
[0017] Furthermore, the fractionation tower is connected to a coking tower via a pipeline, and the coking tower is connected to the heating furnace.
[0018] The beneficial effects of adopting the above-mentioned further technical solution are: after the raw materials are mixed with the circulating oil, they are sent to the heating furnace by the heating furnace feed pump and heated to 490-510℃ before entering the coking tower for coking reaction.
[0019] Furthermore, the raw material preheating furnace is a radiative convection cylindrical furnace.
[0020] The beneficial effect of adopting the above-mentioned further technical solution is to improve heating efficiency.
[0021] Furthermore, the present invention also provides a two-stage needle coke production method, based on a two-stage needle coke production apparatus as described in any one of the above claims. The two-stage needle coke production method includes: S1, during normal operation, cascade control of the raw material outlet temperature and the fuel gas flow rate of the raw material preheating furnace is performed by an adjusting device; S2, when the coke tower is switching and preheating, cascade control of the bottom temperature of the fractionation tower and the fuel gas flow rate of the raw material preheating furnace is performed by an adjusting device.
[0022] The beneficial effects of adopting the technical solution of this invention are as follows: Under normal operation, the raw material preheating furnace operates at a low load. Through cascade control of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace, the feed temperature at the bottom of the fractionation tower is maintained at approximately 320-340℃. When the coke tower undergoes switching and preheating operations, as the oil and gas from the top of the coke tower enters the fractionation tower, the temperature at the bottom of the fractionation tower decreases by approximately 10-25℃. At this time, the fuel gas flow rate control of the raw material preheating furnace is switched to the fractionation tower bottom temperature. Through this cascade adjustment, the bottom temperature of the fractionation tower is raised back to 330-350℃. By adding a raw material preheating furnace to the existing raw material heat exchange system of the needle coke production unit, a two-stage preheating system of "conventional heat exchange + preheating furnace" is formed. An additional raw material preheating facility was added. When the operation of the coking tower might affect the fractionation tower, the new preheating facility increases and stabilizes the temperature at the bottom of the fractionation tower, thereby controlling the gas-liquid and heat balance of the fractionation tower. The product indicators of each side stream are unaffected by fluctuations in coking tower operation, resulting in relatively stable yields and product quality for each product. The independent preheating furnace allows the raw materials to reach a more precise and higher preset temperature before entering the fractionation tower. This effectively reduces the impact of coking tower operation on the gas-liquid and heat balance of the fractionation tower, thus improving the quality of the unit's products. During coking tower cutting and preheating, the temperature at the bottom of the fractionation tower decreases by approximately 10-25°C. The increase and stabilization of the fractionation tower bottom temperature ensures stable heat distribution during the cutting and preheating processes, and this near-steady-state control significantly improves the uniformity of needle coke product quality. By increasing the temperature of the raw materials before entering the fractionation tower, fuel consumption in the heating furnace is reduced. For every 10°C increase in raw material temperature, fuel gas consumption can be reduced by approximately 3%. This achieves energy savings and improved production efficiency to a certain extent.
[0023] Further, step S1 includes: S11, obtaining the actual temperature of the raw material outlet of the raw material preheating furnace, the preset temperature of the raw material outlet of the raw material preheating furnace, and the actual fuel gas flow rate of the raw material preheating furnace; S12, calculating the deviation between the actual temperature of the raw material outlet of the raw material preheating furnace and the preset temperature of the raw material outlet of the raw material preheating furnace; S13, calculating the preset fuel gas flow rate of the raw material preheating furnace based on the deviation between the actual temperature of the raw material outlet of the raw material preheating furnace and the preset temperature of the raw material outlet of the raw material preheating furnace; S14, calculating the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace; S15, controlling the opening degree of the flow regulating valve based on the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace.
[0024] The beneficial effects of adopting the above-mentioned further technical solution are: under normal operation, the raw material preheating furnace operates at a low load, and the feed temperature at the bottom of the fractionation tower is guaranteed to be about 320-340℃ by cascade control of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace.
[0025] Further, step S2 includes: S21, when the coke tower is switching and preheating, switching the cascade control mode of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace to the cascade control mode of the bottom temperature of the fractionation tower and the fuel gas flow rate of the raw material preheating furnace through a temperature selection switch; S22, obtaining the actual temperature of the bottom of the fractionation tower, the preset temperature of the bottom of the fractionation tower, and the actual fuel gas flow rate of the raw material preheating furnace; S23, calculating the deviation between the actual temperature of the bottom of the fractionation tower and the preset temperature of the bottom of the fractionation tower; S24, calculating the preset fuel gas flow rate of the raw material preheating furnace based on the deviation between the actual temperature of the bottom of the fractionation tower and the preset temperature of the bottom of the fractionation tower; S25, calculating the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace; S26, controlling the opening of the flow regulating valve based on the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace.
[0026] The beneficial effects of adopting the above-mentioned further technical solution are as follows: when the coke tower is switching and preheating, as the oil and gas at the top of the coke tower enter the fractionation tower, the temperature at the bottom of the fractionation tower drops by about 10-25°C. At this time, the fuel gas flow control of the raw material preheating furnace is switched to the temperature at the bottom of the fractionation tower. Through this cascade regulation, the temperature at the bottom of the fractionation tower is raised back to 330-350°C.
[0027] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the structure of a two-stage needle coke production device provided in an embodiment of the present invention.
[0029] Figure 2 This is a schematic flowchart of a two-stage needle coke production method provided in an embodiment of the present invention.
[0030] The reference numerals in the attached diagrams are as follows: 1. Raw material oil / diesel heat exchanger; 2. Raw material oil / gasoline heat exchanger; 3. Raw material oil / wax oil heat exchanger; 4. Raw material preheating furnace; 5. Fractionating tower; 6. Heating furnace feed pump; 7. First temperature control element; 8. Second temperature control element; 9. Flow control element; 10. Flow regulating valve; 11. Temperature selection switch. Detailed Implementation
[0031] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0032] like Figure 1As shown, an embodiment of the present invention provides a two-stage needle coke production apparatus, including: a heat exchange device, a raw material preheating furnace 4, a fractionation tower 5, and a regulating device. The heat exchange device is connected to the raw material preheating furnace 4 through a pipeline, the raw material preheating furnace 4 is connected to the fractionation tower 5 through a pipeline, and the regulating device is connected to both the raw material preheating furnace 4 and the fractionation tower 5.
[0033] The beneficial effects of adopting the technical solution of this invention are as follows: Based on the existing raw material heat exchange in the needle coke production unit, an additional raw material preheating furnace is added, forming a two-stage preheating system of "conventional heat exchange + preheating furnace". This added raw material preheating facility increases and stabilizes the temperature at the bottom of the fractionation tower when the operation of the coke tower might affect the fractionation tower, thereby controlling the gas-liquid and heat balance of the fractionation tower. The product indicators of each side stream are unaffected by fluctuations in coke tower operation, resulting in relatively stable yields and product quality for each product. The independent preheating furnace allows the raw material to reach a more precise and higher preset temperature before entering the fractionation tower. This effectively reduces the impact of coke tower operation on the gas-liquid and heat balance of the fractionation tower, thus improving the quality of the unit's products. During coke tower cutting and preheating, the temperature at the bottom of the fractionation tower decreases by approximately 10-25°C. The increase and stabilization of the fractionation tower bottom temperature ensures stable heat distribution in the coke tower during cutting and preheating, and this near-steady-state control significantly improves the uniformity of needle coke product quality. By increasing the temperature of the feedstock before it enters the fractionation tower, fuel consumption in the heating furnace is reduced. For every 10°C increase in feedstock temperature, fuel gas consumption can be reduced by approximately 3%. This achieves energy savings and improved production efficiency to a certain extent.
[0034] like Figure 1 As shown, the regulating device further includes: a first temperature control element 7, a second temperature control element 8, a flow control element 9, and a flow regulating valve 10. The raw material preheating furnace 4 is connected to fuel gas through a pipeline. The flow regulating valve 10 is installed on the pipeline between the raw material preheating furnace 4 and the fuel gas. The first temperature control element 7 is connected to the pipeline between the raw material preheating furnace 4 and the fractionation tower 5. The second temperature control element 8 is connected to the fractionation tower 5. The flow control element 9 is connected to the first temperature control element 7, the second temperature control element 8, and the flow regulating valve 10, respectively.
[0035] The beneficial effects of adopting the above-mentioned further technical solutions are: the setting of the first temperature control element, the second temperature control element, the flow control element and the flow regulating valve facilitates temperature acquisition, analysis and fuel flow regulation, improves automation and accuracy.
[0036] like Figure 1As shown, the flow control element 9 is further connected to the first temperature control element 7 and the second temperature control element 8 respectively via the temperature selection switch 11.
[0037] The beneficial effects of adopting the above-mentioned further technical solutions are: the setting of the temperature selection switch facilitates the switching of cascade control mode and improves automation.
[0038] In the diagram, TC is the temperature control element, FC is the flow control element, TS is the temperature selection switch, and the valve is the flow regulating valve.
[0039] like Figure 1 As shown, the heat exchange device further includes: a raw oil-diesel heat exchanger 1, a raw oil-gasoline heat exchanger 2, and a raw oil-wax oil heat exchanger 3. The raw oil-diesel heat exchanger 1 is connected to a raw oil self-bound zone. The raw oil-diesel heat exchanger 1 is connected to the raw oil-gasoline heat exchanger 2 through a pipeline. The raw oil-gasoline heat exchanger 2 is connected to the raw oil-wax oil heat exchanger 3 through a pipeline. The raw oil-wax oil heat exchanger 3 is connected to the raw material preheating furnace 4 through a pipeline.
[0040] The beneficial effects of adopting the above-mentioned further technical solution are: the feed oil enters the device from the boundary area and exchanges heat with the feed oil diesel heat exchanger, the feed oil gasoline heat exchanger, and the feed oil wax oil heat exchanger according to the temperature difference.
[0041] like Figure 1 As shown, the fractionation tower 5 is further connected to a heating furnace feed pump 6 via a pipeline, and the heating furnace feed pump 6 is connected to a heating furnace via a pipeline.
[0042] The beneficial effect of adopting the above-mentioned further technical solution is that the raw materials are mixed with circulating oil and then sent to the heating furnace for heating through the heating furnace feed pump.
[0043] Among them, the radiant oil output by the heating furnace feed pump 6 is sent to the heating furnace.
[0044] like Figure 1 As shown, the fractionation tower 5 is further connected to a coke tower via a pipeline, and the coke tower is connected to the heating furnace.
[0045] The beneficial effects of adopting the above-mentioned further technical solution are: after the raw materials are mixed with the circulating oil, they are sent to the heating furnace by the heating furnace feed pump and heated to 490-510℃ before entering the coking tower for coking reaction.
[0046] The oil and gas from the top of the coke tower enters the fractionation tower.
[0047] Furthermore, the raw material preheating furnace 4 is a radiative convection cylindrical furnace.
[0048] The beneficial effect of adopting the above-mentioned further technical solution is to improve heating efficiency.
[0049] The raw material preheating furnace is a radiant-convection cylindrical furnace (radiant-convection cylindrical furnace), heated by fuel gas. It employs a single-pass design, with fuel gas entering the heating furnace (the heating furnace within the raw material preheating furnace) from the upper part of the convection chamber. After convection heating, it enters the upper part of the radiant chamber via the oil transfer line, and after radiant heating, exits the raw material preheating furnace 4 from the upper part of the radiant chamber. The radiant chamber uses a vertical tube configuration, while the convection chamber uses a shielded tube + finned tube structure. The raw material preheating furnace 4 is divided into two parts: a radiant chamber and a convection chamber. The upper part is the convection chamber, and the lower part is the radiant chamber. Both the radiant chamber and the convection chamber are located within the raw material preheating furnace.
[0050] Conventional raw material preheating utilizes a high-temperature heat source on the side stream of the fractionation tower. The heat exchange network, as an organic whole, is interconnected; any change in one part affects the entire system. The purpose of this invention is to add a raw material preheating facility. When the operation of the coke tower may affect the fractionation tower, the newly added preheating facility increases and stabilizes the temperature at the bottom of the fractionation tower, thereby controlling the gas-liquid and heat balance of the fractionation tower. The product indicators of each side stream are unaffected by fluctuations in coke tower operation, resulting in relatively stable product yields and quality for the unit (two-stage needle coke production unit).
[0051] This invention adds a raw material preheating furnace to the existing raw material heat exchange of the needle coke production unit, forming a two-stage preheating system of "conventional heat exchange + preheating furnace".
[0052] The feedstock oil enters the unit (two-stage needle coke production unit) from the boundary area. According to the temperature difference, it exchanges heat with the feedstock oil-diesel heat exchanger (feedstock oil-diesel heat exchanger 1), the feedstock oil-gasoline heat exchanger (feedstock oil-gasoline heat exchanger 2), and the feedstock oil-wax oil heat exchanger (feedstock oil-wax oil heat exchanger 3). After being heated to about 300°C, it enters the newly set feedstock preheating furnace 4. After being heated, it enters the fractionation tower 5. The feedstock is mixed with the circulating oil and then sent to the heating furnace by the heating furnace feed pump 6. After being heated to 490-510°C, it enters the coking tower for coking reaction.
[0053] The fuel gas regulating valve (flow regulating valve) setting selection module for the raw material preheater 4 is configured. Under normal operation, the raw material outlet temperature and fuel gas flow rate of the raw material preheater 4 are cascaded to maintain a constant outlet temperature of 320-340℃. When the coke tower is switching or undergoing preheating operations, the bottom temperature of the fractionation tower 5 is cascaded to maintain a constant bottom temperature of 330-350℃ by increasing the load on the raw material preheater 4.
[0054] like Figure 2As shown, the present invention also provides a two-stage needle coke production method. Based on the two-stage needle coke production apparatus described in any one of the above, the two-stage needle coke production method includes: S1, during normal operation, the raw material outlet temperature of the raw material preheating furnace and the fuel gas flow rate of the raw material preheating furnace are controlled in cascade by an adjusting device; S2, when the coke tower is switching and preheating, the bottom temperature of the fractionation tower and the fuel gas flow rate of the raw material preheating furnace are controlled in cascade by an adjusting device.
[0055] The beneficial effects of adopting the technical solution of this invention are as follows: Under normal operation, the raw material preheating furnace operates at a low load. Through cascade control of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace, the feed temperature at the bottom of the fractionation tower is maintained at approximately 320-340℃. When the coke tower undergoes switching and preheating operations, as the oil and gas from the top of the coke tower enters the fractionation tower, the temperature at the bottom of the fractionation tower decreases by approximately 10-25℃. At this time, the fuel gas flow rate control of the raw material preheating furnace is switched to the fractionation tower bottom temperature. Through this cascade adjustment, the bottom temperature of the fractionation tower is raised back to 330-350℃. By adding a raw material preheating furnace to the existing raw material heat exchange system of the needle coke production unit, a two-stage preheating system of "conventional heat exchange + preheating furnace" is formed. An additional raw material preheating facility was added. When the operation of the coking tower might affect the fractionation tower, the new preheating facility increases and stabilizes the temperature at the bottom of the fractionation tower, thereby controlling the gas-liquid and heat balance of the fractionation tower. The product indicators of each side stream are unaffected by fluctuations in coking tower operation, resulting in relatively stable yields and product quality for each product. The independent preheating furnace allows the raw materials to reach a more precise and higher preset temperature before entering the fractionation tower. This effectively reduces the impact of coking tower operation on the gas-liquid and heat balance of the fractionation tower, thus improving the quality of the unit's products. During coking tower cutting and preheating, the temperature at the bottom of the fractionation tower decreases by approximately 10-25°C. The increase and stabilization of the fractionation tower bottom temperature ensures stable heat distribution during the cutting and preheating processes, and this near-steady-state control significantly improves the uniformity of needle coke product quality. By increasing the temperature of the raw materials before entering the fractionation tower, fuel consumption in the heating furnace is reduced. For every 10°C increase in raw material temperature, fuel gas consumption can be reduced by approximately 3%. This achieves energy savings and improved production efficiency to a certain extent.
[0056] Further, step S1 includes: S11, obtaining the actual temperature of the raw material outlet of the raw material preheating furnace, the preset temperature of the raw material outlet of the raw material preheating furnace, and the actual fuel gas flow rate of the raw material preheating furnace; S12, calculating the deviation between the actual temperature of the raw material outlet of the raw material preheating furnace and the preset temperature of the raw material outlet of the raw material preheating furnace; S13, calculating the preset fuel gas flow rate of the raw material preheating furnace based on the deviation between the actual temperature of the raw material outlet of the raw material preheating furnace and the preset temperature of the raw material outlet of the raw material preheating furnace; S14, calculating the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace; S15, controlling the opening degree of the flow regulating valve based on the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace.
[0057] The beneficial effects of adopting the above-mentioned further technical solution are: under normal operation, the raw material preheating furnace operates at a low load, and the feed temperature at the bottom of the fractionation tower is guaranteed to be about 320-340℃ by cascade control of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace.
[0058] This cascade control (which uses a regulating device to cascade control the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace) aims to precisely control the raw material outlet temperature of the raw material preheating furnace 4 by adjusting the fuel gas flow rate.
[0059] This cascade control system consists of two control loops: a main loop and a secondary loop. The controlled variable in the main loop is the raw material outlet temperature of the raw material preheater 4, while the controlled variable in the secondary loop is the fuel gas flow rate. The main controller adjusts the setpoint of the secondary controller based on the deviation between the setpoint and the actual measured value of the raw material outlet temperature of the raw material preheater 4. The secondary controller, in turn, controls the opening of the flow regulating valve based on the deviation between the setpoint and the actual measured value of the fuel gas flow rate, thereby regulating the fuel gas flow rate.
[0060] Further, step S2 includes: S21, when the coke tower is switching and preheating, switching the cascade control mode of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace to the cascade control mode of the bottom temperature of the fractionation tower and the fuel gas flow rate of the raw material preheating furnace through a temperature selection switch; S22, obtaining the actual temperature of the bottom of the fractionation tower, the preset temperature of the bottom of the fractionation tower, and the actual fuel gas flow rate of the raw material preheating furnace; S23, calculating the deviation between the actual temperature of the bottom of the fractionation tower and the preset temperature of the bottom of the fractionation tower; S24, calculating the preset fuel gas flow rate of the raw material preheating furnace based on the deviation between the actual temperature of the bottom of the fractionation tower and the preset temperature of the bottom of the fractionation tower; S25, calculating the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace; S26, controlling the opening of the flow regulating valve based on the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace.
[0061] The beneficial effects of adopting the above-mentioned further technical solution are as follows: when the coke tower is switching and preheating, as the oil and gas at the top of the coke tower enter the fractionation tower, the temperature at the bottom of the fractionation tower drops by about 10-25°C. At this time, the fuel gas flow control of the raw material preheating furnace is switched to the temperature at the bottom of the fractionation tower. Through this cascade regulation, the temperature at the bottom of the fractionation tower is raised back to 330-350°C.
[0062] This cascade control (which uses a regulating device to cascade control the bottom temperature of the fractionation tower and the fuel gas flow rate of the feed preheater) aims to precisely control the bottom temperature of fractionation tower 5 by adjusting the fuel gas flow rate.
[0063] This cascade control system consists of two control loops: a main loop and a secondary loop. The controlled variable in the main loop is the bottom temperature of fractionation column 5, while the controlled variable in the secondary loop is the fuel gas flow rate. The main controller adjusts the setpoint of the secondary controller based on the deviation between the setpoint and the actual measured value of the bottom temperature of fractionation column 5. The secondary controller, in turn, controls the opening of the regulating valve (flow control valve) based on the deviation between the setpoint and the actual measured value of the fuel gas flow rate, thereby regulating the fuel gas flow rate.
[0064] During normal operation, the raw material preheater 4 operates at a low load. The feed temperature at the preheater 4 is controlled in cascade with the fuel gas flow rate to maintain the bottom feed temperature of the fractionation tower at approximately 320-340℃. When the coke tower undergoes switching and preheating operations, as the oil and gas from the top of the coke tower enters the fractionation tower 5, the bottom temperature of the fractionation tower 5 decreases by approximately 10-25℃. At this time, the fuel gas flow rate control of the preheater 4 is switched to adjust the bottom temperature of the fractionation tower 5. This cascade adjustment raises the bottom temperature of the fractionation tower 5 back to 330-350℃.
[0065] The design of this heating furnace (raw material preheating furnace) not only meets the daily requirements for increasing and stabilizing the bottom temperature of the fractionation tower, but also enriches the heating methods for the unit's start-up conditions, making production operations more flexible.
[0066] This invention achieves the following effects through a two-stage preheating system consisting of "conventional heat exchange + preheating furnace":
[0067] 1) The independent preheating furnace (raw material preheating furnace 4) enables the raw materials to reach a more precise and higher preset temperature before entering the fractionation tower.
[0068] 2) It effectively reduces the impact of coke tower operation on the gas-liquid balance and heat balance of the fractionation tower, thereby improving the quality of the unit's products.
[0069] 3) During the cutting and preheating process of the coke tower, the temperature at the bottom of the fractionation tower decreases by about 10-25℃. The increase and stabilization of the temperature at the bottom of the fractionation tower ensures the heat stability of the coke tower during the cutting and preheating process. The steady-state control significantly improves the uniformity of needle coke product quality.
[0070] 4) By increasing the temperature of the raw materials before they enter the fractionation tower, fuel consumption in the heating furnace is reduced. For every 10°C increase in raw material temperature, fuel gas consumption can be reduced by approximately 3%. This achieves energy savings and improves production efficiency to a certain extent.
[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A two-stage needle coke production apparatus, characterized in that, include: The system includes a heat exchanger, a raw material preheating furnace, a fractionating tower, and a regulating device. The heat exchanger is connected to the raw material preheating furnace via a pipeline, and the raw material preheating furnace is connected to the fractionating tower via a pipeline. The regulating device is connected to both the raw material preheating furnace and the fractionating tower.
2. The two-stage needle coke production apparatus according to claim 1, characterized in that, The regulating device includes: a first temperature control element, a second temperature control element, a flow control element, and a flow regulating valve. The raw material preheating furnace is connected to fuel gas via a pipeline. The flow regulating valve is installed on the pipeline between the raw material preheating furnace and the fuel gas. The first temperature control element is connected to the pipeline between the raw material preheating furnace and the fractionation tower. The second temperature control element is connected to the fractionation tower. The flow control element is connected to the first temperature control element, the second temperature control element, and the flow regulating valve, respectively.
3. The two-stage needle coke production apparatus according to claim 2, characterized in that, The flow control element is connected to the first temperature control element and the second temperature control element respectively via a temperature selection switch.
4. A two-stage needle coke production apparatus according to claim 1, characterized in that, The heat exchange device includes: a feedstock oil / diesel heat exchanger, a feedstock oil / gasoline heat exchanger, and a feedstock oil / wax oil heat exchanger. The feedstock oil / diesel heat exchanger is connected to a feedstock oil self-bound zone. The feedstock oil / diesel heat exchanger is connected to the feedstock oil / gasoline heat exchanger via a pipeline. The feedstock oil / gasoline heat exchanger is connected to the feedstock oil / wax oil heat exchanger via a pipeline. The feedstock oil / wax oil heat exchanger is connected to the feedstock preheating furnace via a pipeline.
5. A two-stage needle coke production apparatus according to claim 1, characterized in that, The fractionation tower is connected to a heating furnace feed pump via a pipeline, and the heating furnace feed pump is connected to a heating furnace via a pipeline.
6. A two-stage needle coke production apparatus according to claim 5, characterized in that, The fractionation tower is connected to a coking tower via a pipeline, and the coking tower is connected to the heating furnace.
7. A two-stage needle coke production apparatus according to claim 1, characterized in that, The raw material preheating furnace is a radiation convection cylindrical furnace.
8. A two-stage method for producing needle coke, characterized in that, According to any one of claims 1 to 7, a two-stage needle coke production apparatus and a two-stage needle coke production method include: S1. During normal operation, the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace are controlled in cascade by the regulating device. S2. When the coke tower is switching and preheating, the bottom temperature of the fractionation tower and the fuel gas flow rate of the raw material preheating furnace are controlled in cascade by the regulating device.
9. A two-stage needle coke production method according to claim 8, characterized in that, Step S1 includes: S11. Obtain the actual temperature of the raw material outlet of the raw material preheating furnace, the preset temperature of the raw material outlet of the raw material preheating furnace, and the actual fuel gas flow rate of the raw material preheating furnace. S12. Calculate the deviation between the actual temperature of the raw material outlet of the raw material preheating furnace and the preset temperature of the raw material outlet of the raw material preheating furnace. S13. Calculate the preset fuel gas flow rate of the raw material preheating furnace based on the deviation between the actual temperature of the raw material outlet of the raw material preheating furnace and the preset temperature of the raw material outlet of the raw material preheating furnace. S14. Calculate the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace; S15. Control the opening of the flow regulating valve based on the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace.
10. A two-stage needle coke production method according to claim 8, characterized in that, Step S2 includes: S21. When the coke tower is switching and preheating, the mode of cascade control of the raw material outlet temperature and fuel gas flow rate of the raw material preheating furnace is switched to the mode of cascade control of the bottom temperature of the fractionation tower and the fuel gas flow rate of the raw material preheating furnace through the temperature selection switch. S22. Obtain the actual temperature at the bottom of the fractionation column, the preset temperature at the bottom of the fractionation column, and the actual fuel gas flow rate of the feed preheater. S23. Calculate the deviation between the actual temperature at the bottom of the fractionation column and the preset temperature at the bottom of the fractionation column; S24. Calculate the preset fuel gas flow rate of the raw material preheater based on the deviation between the actual temperature at the bottom of the fractionation column and the preset temperature at the bottom of the fractionation column. S25. Calculate the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace; S26. Control the opening of the flow regulating valve based on the deviation between the actual fuel gas flow rate of the raw material preheating furnace and the preset fuel gas flow rate of the raw material preheating furnace.