On-line cleaning method and acceptance system for heat transfer oil heat exchange system

Abstract

The invention discloses an on-line cleaning method and acceptance system for a heat transfer oil heat exchange system, and relates to the technical field of heat exchange equipment, comprising the following steps: pre-preparation before cleaning, on-line cleaning process, sampling detection after cleaning, and acceptance process after cleaning. The acceptance system comprises a master control center, a data acquisition unit, a residual carbon value approval unit, an oil coke cleaning rate approval unit and an acceptance result output unit. The heat transfer oil coke distribution state of the heat exchange system is detected before and after cleaning, cleaning demand prediction is conducted according to the heat transfer oil coke distribution state before cleaning, the effects of saving the cleaning cost and improving the cleaning efficiency are achieved, the cleaning result is checked and accepted according to the heat transfer oil coke distribution state after cleaning, and the cleaning efficiency is improved. The cleaning device can be suitable for cleaning spongy coke and honeycomb coke when the flow speed of heat conduction oil is larger than one meter per second, the cleaning effect is good, and it can be guaranteed that the cleaned heat exchange system reaches the standard heat exchange efficiency after confirmation of an acceptance system.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchange equipment, and in particular to an online cleaning method and an acceptance system for a heat transfer oil heat exchange system. Background Art

[0002] Thermal oil heating circulation system is a heating system that uses thermal oil to transfer heat energy. It uses thermal oil as a heat transfer medium to transfer heat to the heating object through a heater to achieve a heating method. Thermal oil is a special liquid medium with good heat transfer performance and chemical stability. It can withstand high temperature and high pressure, and is not easy to evaporate or decompose. It plays a role in heat transfer and energy storage in the heating cycle.

[0003] Any oil will oxidize in the air, and thermal oil is no exception. The oxidation rate of the oil is proportional to the oil-oxygen contact area. When thermal oil is running at high temperature, two types of chemical reactions will occur: cracking and condensation:

[0004] Fragmentation will turn large molecules into light, small molecules;

[0005] Condensation will turn small molecules into viscous macromolecules, which will precipitate and adsorb on the tube wall to form sponge coke, honeycomb coke or needle coke, which will slow down the flow rate of the heat transfer oil and increase its residence time in the furnace tube. This will not only reduce the heat transfer effect, but also accelerate the degradation of the heat transfer oil, shorten its service life, and affect the safe and stable operation of the system. Therefore, the heat exchanger needs to be cleaned. The cleaning time and effect will be different due to different coke shapes.

[0006] In view of the above technical defects, a solution is now proposed. Summary of the invention

[0007] The purpose of the present invention is to predict the cleaning demand according to the distribution state of the heat transfer oil coke before cleaning, thereby achieving the effect of saving cleaning costs and improving cleaning efficiency, and accepting the cleaning results according to the distribution state of the heat transfer oil coke after cleaning. The present invention can be applied to the cleaning of sponge coke and honeycomb coke when the flow rate of the heat transfer oil is greater than one meter per second, and the cleaning effect is good. After confirmation by the acceptance system, it can be guaranteed that the heat exchange system after cleaning reaches the standard heat exchange efficiency.

[0008] In order to achieve the above object, the present invention adopts the following technical solution: an online cleaning method for a heat transfer oil heat exchange system, comprising the following steps:

[0009] Step 1: Preparatory work before cleaning:

[0010] S101, obtaining operation data of the heat exchange system, wherein the operation data includes activation time of the heat exchange system, oil quantity, problems existing in use, and location information of sampling ports;

[0011] S102, cutting off a section of the main pipeline in the heat exchange system as the acceptance pipeline;

[0012] S103, inspecting the coke data of the heat transfer oil before and after cleaning the pipeline by visual geometric area method, wherein the coke data of the heat transfer oil includes coke type, thickness, coverage area and pipeline blockage;

[0013] Specifically, if the pipeline is blocked, it should be cleaned after manual unblocking, and the flow rate of parallel pipelines should be measured to confirm whether the bottom valve is installed at the lowest point of the heat exchange system, and whether the horizontal pipeline can drain the heat transfer oil;

[0014] Step 2: Online cleaning process:

[0015] S201, pre-calculation: obtaining the amount of oil in the heat exchange system, and calculating the amount of cleaning agent to be purchased according to the amount of oil in the heat exchange system and the coke state data of the heat transfer oil;

[0016] S202, cooling: cooling the heat transfer oil to 60°C or below while circulating in the heat exchange system;

[0017] S203, draining oil: drain the heat transfer oil in the high-level tank first, and then drain the heat transfer oil in an amount equal to the amount of online cleaning agent;

[0018] S204, adding agent: adding online cleaning agent from the high-level tank until the oil level reaches the normal operation of the heat exchange system;

[0019] S205, circulation: start the circulation pump of the heat exchange system, cold circulate for 1 hour, and confirm that the heat exchange system is in normal working condition.

[0020] S206, heating: heating the heat transfer oil to the working temperature and maintaining it;

[0021] Step 3: Sampling and testing after cleaning:

[0022] S301. According to the manual sampling method for petroleum liquids in GB / T4756, take 1 liter of sample from the sampling port of the heat exchange system as a sample for inspection before cleaning, after adding online cleaning agent, when the heat transfer oil reaches the working temperature, and every 12 hours thereafter;

[0023] S302. Obtain the sample to be tested, and test the residual carbon content in the sample according to the residual carbon determination method for petroleum products in SH / T0170.

[0024] Furthermore, the flow rate of the heat exchange oil in the acceptance pipeline in S103 is greater than 1 m / s.

[0025] Furthermore, in S206, when the heat transfer oil generates pressure fluctuations due to dehydration and degassing in the heat exchange system, the temperature of the heat transfer oil is first reduced so that the pressure fluctuation of the heat transfer oil reaches equilibrium and then the temperature is increased. The heat transfer oil is heated to the operating temperature by repeated temperature reduction and temperature increase.

[0026] The present invention also provides an acceptance system for an online cleaning method of a heat transfer oil heat exchange system, comprising a general control center, a data acquisition unit, a residual carbon value verification unit, an oil coke cleaning rate verification unit, and an acceptance result output unit;

[0027] The data acquisition unit is used to obtain the residual carbon content test values ​​of several groups of samples for inspection and the data of the coke state of the heat transfer oil before the cleaning of the acceptance pipeline, integrate them into a data set to be approved and send them to the residual carbon value approval unit and the oil coke cleaning rate approval unit;

[0028] The carbon residue value verification unit obtains and processes the data set to be verified, calculates the average carbon residue content by using the carbon residue content detection values ​​in a number of consecutive samples through standard deviation analysis, and then calculates the carbon residue content evaluation coefficient based on the average carbon residue content. The cleaning effect is judged based on the preset carbon residue content evaluation threshold, so as to generate a cleaning qualified signal and send it to the oil coke cleaning rate verification unit or a secondary cleaning signal and send it to the cleaning drive unit;

[0029] The cleaning drive unit is used to obtain the secondary cleaning signal and generate a cleaning instruction to the main control center of the heat exchange system. After the secondary cleaning, the detection and sampling are performed again to obtain the data set to be approved after the secondary cleaning and send it to the residual carbon value approval unit;

[0030] After the oil coke cleaning rate verification unit obtains the cleaning qualified signal, it obtains the coke coverage area in the acceptance pipeline after cleaning by visual geometry method, calculates the heat transfer oil coke cleaning rate according to the heat transfer oil coke state data before the acceptance pipeline is cleaned, and sends the heat transfer oil coke cleaning rate to the acceptance result output unit;

[0031] The acceptance result output unit obtains and processes the thermal oil coke cleaning rate, and determines the thermal oil coke cleaning pass rate according to a preset thermal oil coke cleaning judgment threshold to generate an acceptance pass signal or an acceptance failure signal and output it to the main control center of the heat exchange system.

[0032] Furthermore, the specific process of generating a cleaning qualified signal or a secondary cleaning signal is as follows:

[0033] S401. Obtain the residual carbon content test values ​​of several groups of samples for inspection: x1, x2, x3, ..., xn, and calculate the average value of the residual carbon content according to the formula Where n is the number of samples to be tested for the determination of residual carbon content;

[0034] S402. Calculate the residual carbon content evaluation coefficient according to the following formula: The residual carbon content evaluation coefficient is used to measure the residual carbon content in the acceptance pipeline after the reaction heat transfer oil heat exchange system is cleaned. The higher the residual carbon content evaluation coefficient is, the higher the residual carbon content in the acceptance pipeline is, and the worse the cleaning effect is. On the contrary, the lower the residual carbon content evaluation coefficient is, the lower the residual carbon content in the acceptance pipeline is, and the better the cleaning effect is.

[0035] S403, obtaining a preset residual carbon content evaluation threshold xt: xt=k·σ, where k is a preset proportionality coefficient. If the residual carbon content evaluation coefficient is less than the residual carbon content evaluation threshold, it means that the cleaning effect meets the acceptance standard, and a cleaning qualified signal is generated;

[0036] If the residual carbon content evaluation coefficient is greater than or equal to the residual carbon content evaluation threshold, it means that the cleaning effect does not meet the acceptance standard and a secondary cleaning signal is generated.

[0037] Furthermore, the specific process of generating an acceptance pass signal or an acceptance fail signal is as follows:

[0038] S501. Obtain the coke coverage area y in the acceptance pipeline after cleaning by visual geometry method, and calculate the heat transfer oil coke cleaning rate B according to the following formula: Where y0 is the coke coverage area in the acceptance pipeline before cleaning, and the thermal oil coke cleaning rate is used to reflect the change in the coke coverage area in the acceptance pipeline before and after cleaning. The higher the thermal oil coke cleaning rate, the better the cleaning effect, and vice versa, the lower the thermal oil coke cleaning rate, the worse the cleaning effect;

[0039] S502, obtaining a preset thermal oil coke cleaning judgment threshold Bm. If the thermal oil coke cleaning rate is less than the thermal oil coke cleaning judgment threshold, it means that the thermal oil coke cleaning effect does not meet the acceptance standard, and an acceptance failure signal is generated;

[0040] If the thermal oil coke cleaning rate is greater than or equal to the thermal oil coke cleaning judgment threshold, it means that the thermal oil coke cleaning effect has reached the acceptance standard, and an acceptance pass signal is generated.

[0041] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0042] The present invention detects the distribution state of the heat transfer oil coke of the heat exchange system before and after cleaning, predicts the cleaning demand according to the distribution state of the heat transfer oil coke before cleaning, saves the cleaning cost and improves the cleaning efficiency, and accepts the cleaning result according to the distribution state of the heat transfer oil coke after cleaning. The invention can be applicable to the cleaning of sponge coke and honeycomb coke when the flow rate of the heat transfer oil is greater than one meter per second, and has a good cleaning effect. After confirmation by the acceptance system, it can be ensured that the cleaned heat exchange system reaches the standard heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1A schematic diagram of the method flow of the present invention is shown;

[0044] Figure 2 The schematic diagram of the structure of the acceptance system of the present invention is shown;

[0045] Figure 3 The schematic diagram of the process of the residual carbon value verification unit and the oil coke cleaning rate verification unit of the present invention is shown. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Embodiment 1:

[0048] like Figure 1-3 As shown, an online cleaning method for a heat transfer oil heat exchange system comprises the following steps:

[0049] Step 1: Preparatory work before cleaning:

[0050] S101, obtaining operation data of the heat exchange system, the operation data including activation time of the heat exchange system, oil quantity, problems existing in use and location information of sampling ports;

[0051] S102, cutting off a section of the main pipeline in the heat exchange system as the acceptance pipeline;

[0052] S103, inspecting the coke data of the heat transfer oil before and after pipeline cleaning by visual geometric area method, the coke data of the heat transfer oil including coke type, thickness, coverage area and pipeline blockage;

[0053] Specifically, if the pipeline is blocked, it should be cleaned after manual unblocking, and the flow rate of parallel pipelines should be measured to confirm whether the bottom valve is installed at the lowest point of the heat exchange system, and whether the horizontal pipeline can drain the heat transfer oil;

[0054] Step 2: Online cleaning process:

[0055] S201, pre-calculation: obtaining the amount of oil in the heat exchange system, and calculating the amount of cleaning agent to be purchased according to the amount of oil in the heat exchange system and the coke state data of the heat transfer oil;

[0056] S202, cooling: cooling the heat transfer oil to 60°C or below while circulating in the heat exchange system;

[0057] S203, draining oil: drain the heat transfer oil in the high-level tank first, and then drain the heat transfer oil in an amount equal to the amount of online cleaning agent;

[0058] S204, adding agent: adding online cleaning agent from the high-level tank until the oil level reaches the normal operation of the heat exchange system;

[0059] S205, circulation: start the circulation pump of the heat exchange system, cold circulate for 1 hour, and confirm that the heat exchange system is in normal working condition.

[0060] S206, heating: heating the heat transfer oil to the working temperature and maintaining it;

[0061] Step 3: Sampling and testing after cleaning:

[0062] S301. According to the manual sampling method for petroleum liquids in GB / T4756, take 1 liter of sample from the sampling port of the heat exchange system as a sample for inspection before cleaning, after adding online cleaning agent, when the heat transfer oil reaches the working temperature, and every 12 hours thereafter;

[0063] S302. Obtain the sample to be tested, and test the residual carbon content in the sample according to the residual carbon determination method for petroleum products in SH / T0170.

[0064] The flow rate of the heat exchange oil in the acceptance pipeline in S103 is greater than 1 m / s.

[0065] In S206, when the heat transfer oil generates pressure fluctuations due to dehydration and degassing in the heat exchange system, the temperature of the heat transfer oil is first reduced so that the pressure fluctuation of the heat transfer oil reaches equilibrium and then the temperature is increased. The heat transfer oil is heated to the operating temperature through repeated temperature reduction and temperature increase.

[0066] Embodiment 2:

[0067] like Figure 2-3 As shown, the present invention also provides an acceptance system for an online cleaning method of a heat transfer oil heat exchange system, comprising a general control center, a data acquisition unit, a residual carbon value verification unit, an oil coke cleaning rate verification unit, and an acceptance result output unit;

[0068] The data acquisition unit is used to obtain the residual carbon content test values ​​of several groups of samples for inspection and the data of the coke state of the heat transfer oil before the cleaning of the acceptance pipeline, integrate them into a data set to be approved and send them to the residual carbon value approval unit and the oil coke cleaning rate approval unit;

[0069] The carbon residue value verification unit obtains and processes the data set to be verified, calculates the average carbon residue content by using the carbon residue content detection values ​​in a number of consecutive samples through standard deviation analysis, and then calculates the carbon residue content evaluation coefficient based on the average carbon residue content. The cleaning effect is judged based on the preset carbon residue content evaluation threshold, so as to generate a cleaning qualified signal and send it to the oil coke cleaning rate verification unit or a secondary cleaning signal and send it to the cleaning drive unit;

[0070] The specific process of generating a cleaning qualified signal or a secondary cleaning signal is as follows:

[0071] S401. Obtain the residual carbon content test values ​​of several groups of samples for inspection: x1, x2, x3, ..., xn, and calculate the average value of the residual carbon content according to the formula Where n is the number of samples to be tested for the determination of residual carbon content;

[0072] S402. Calculate the residual carbon content evaluation coefficient according to the following formula: Among them, n-1 is the degree of freedom, and the residual carbon content evaluation coefficient is used to reflect the residual carbon content in the acceptance pipeline after the thermal oil heat exchange system is cleaned. The higher the residual carbon content evaluation coefficient, the higher the residual carbon content in the acceptance pipeline, and the worse the cleaning effect. On the contrary, the lower the residual carbon content evaluation coefficient, the lower the residual carbon content in the acceptance pipeline, and the better the cleaning effect.

[0073] Specifically, in the measurement of a group of samples, the larger the σ number, the smaller the probability of falling near the average value of the residual carbon content, which means that the measurement accuracy is worse and the distribution density curve is flatter; conversely, the smaller the σ number, the greater the probability of falling near the average value of the residual carbon content, which means that the measurement accuracy is better and the distribution density curve is steeper.

[0074] When the deviation of the measured value of the same sample is less than 2σ, the probability is less than 5%. When the deviation of the measured value of the same sample is greater than or equal to 2σ, the probability is even smaller.

[0075] In laboratory tests, if the measured value deviation is greater than or equal to 2σ, it can be determined that this group of measured values ​​are not the same sample; if the measured deviation is less than 2σ, it can be determined that this group of measured values ​​are the same sample value;

[0076] S403, obtaining a preset residual carbon content evaluation threshold xt: xt=k·σ, where k is a preset proportionality coefficient. If the residual carbon content evaluation coefficient is less than the residual carbon content evaluation threshold, it means that the cleaning effect meets the acceptance standard, and a cleaning qualified signal is generated;

[0077] If the residual carbon content evaluation coefficient is greater than or equal to the residual carbon content evaluation threshold, it means that the cleaning effect does not meet the acceptance standard and a secondary cleaning signal is generated.

[0078] The cleaning drive unit is used to obtain the secondary cleaning signal and generate a cleaning instruction to the main control center of the heat exchange system. After the secondary cleaning, the detection and sampling are performed again to obtain the data set to be approved after the secondary cleaning and send it to the residual carbon value approval unit;

[0079] After the oil coke cleaning rate verification unit obtains the cleaning qualified signal, it obtains the coke coverage area in the acceptance pipeline after cleaning by visual geometry method, calculates the heat transfer oil coke cleaning rate according to the heat transfer oil coke state data before the acceptance pipeline is cleaned, and sends the heat transfer oil coke cleaning rate to the acceptance result output unit;

[0080] The acceptance result output unit obtains and processes the thermal oil coke cleaning rate, and determines the thermal oil coke cleaning pass rate according to a preset thermal oil coke cleaning judgment threshold to generate an acceptance pass signal or an acceptance failure signal and output it to the main control center of the heat exchange system.

[0081] The specific process of generating a pass signal or a fail signal is as follows:

[0082] S501. Obtain the coke coverage area y in the acceptance pipeline after cleaning by visual geometry method, and calculate the heat transfer oil coke cleaning rate B according to the following formula: Where y0 is the coke coverage area in the acceptance pipeline before cleaning, and the thermal oil coke cleaning rate is used to reflect the change in the coke coverage area in the acceptance pipeline before and after cleaning. The higher the thermal oil coke cleaning rate, the better the cleaning effect, and vice versa, the lower the thermal oil coke cleaning rate, the worse the cleaning effect;

[0083] S502, obtaining a preset thermal oil coke cleaning judgment threshold Bm. If the thermal oil coke cleaning rate is less than the thermal oil coke cleaning judgment threshold, it means that the thermal oil coke cleaning effect does not meet the acceptance standard, and an acceptance failure signal is generated;

[0084] If the thermal oil coke cleaning rate is greater than or equal to the thermal oil coke cleaning judgment threshold, it means that the thermal oil coke cleaning effect has reached the acceptance standard, and an acceptance pass signal is generated.

[0085] The present invention detects the distribution state of the heat transfer oil coke of the heat exchange system before and after cleaning, predicts the cleaning demand according to the distribution state of the heat transfer oil coke before cleaning, saves the cleaning cost and improves the cleaning efficiency, and accepts the cleaning result according to the distribution state of the heat transfer oil coke after cleaning. The invention can be applicable to the cleaning of sponge coke and honeycomb coke when the flow rate of the heat transfer oil is greater than one meter per second, and has a good cleaning effect. After confirmation by the acceptance system, it can be ensured that the cleaned heat exchange system reaches the standard heat exchange efficiency.

[0086] The threshold is set to facilitate comparison. The size of the threshold depends on the amount of sample data and the number of bases set by technicians in this field for each group of sample data; as long as it does not affect the proportional relationship between the parameter and the quantized value.

[0087] The above formulas are all dimensionless and numerical calculations. The formula is a formula obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0088] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An online cleaning method for a heat transfer oil heat exchange system, characterized in that: The following steps are involved: Step 1: Preparatory work before cleaning: S101, obtaining operation data of the heat exchange system, wherein the operation data includes activation time of the heat exchange system, oil quantity, problems existing in use, and location information of sampling ports; S102, cutting off a section of the main pipeline in the heat exchange system as the acceptance pipeline; S103, inspecting the coke data of the heat transfer oil before and after cleaning the pipeline by visual geometric area method, wherein the coke data of the heat transfer oil includes coke type, thickness, coverage area and pipeline blockage; Step 2: Online cleaning process: S201, pre-calculation: obtaining the amount of oil in the heat exchange system, and calculating the amount of cleaning agent to be purchased according to the amount of oil in the heat exchange system and the coke state data of the heat transfer oil; S202, cooling: cooling the heat transfer oil to 60°C or below while circulating in the heat exchange system; S203, draining oil: drain the heat transfer oil in the high-level tank first, and then drain the heat transfer oil in an amount equal to the amount of online cleaning agent; S204, adding agent: adding online cleaning agent from the high-level tank until the oil level reaches the normal operation of the heat exchange system; S205, circulation: start the circulation pump of the heat exchange system, cold circulate for 1 hour, and confirm that the heat exchange system is in normal working condition. S206, heating: heating the heat transfer oil to the working temperature and maintaining it; Step 3: Sampling and testing after cleaning: S301. According to the manual sampling method for petroleum liquids in GB / T4756, take 1 liter of sample from the sampling port of the heat exchange system as a sample for inspection before cleaning, after adding online cleaning agent, when the heat transfer oil reaches the working temperature, and every 12 hours thereafter; S302. Obtain the sample to be tested, and test the residual carbon content in the sample according to the residual carbon determination method for petroleum products in SH / T0170.

2. The online cleaning method and acceptance system of the thermal oil heat exchange system according to claim 1 is characterized in that: In the S103, the flow rate of the heat exchange oil in the acceptance pipeline is greater than 1 m / s.

3. The online cleaning method and acceptance system of the thermal oil heat exchange system according to claim 1 is characterized in that: In S206, when the heat transfer oil generates pressure fluctuations due to dehydration and degassing in the heat exchange system, the temperature of the heat transfer oil is first reduced so that the pressure fluctuation of the heat transfer oil reaches equilibrium and then the temperature is increased. The heat transfer oil is heated to the operating temperature by repeated temperature reduction and temperature increase.

4. An acceptance system for an online cleaning method for a heat transfer oil heat exchange system according to any one of claims 1 to 3, characterized in that: It includes the general control center, data acquisition unit, residual carbon value verification unit, oil coke cleaning rate verification unit, and acceptance result output unit; The data acquisition unit is used to obtain the residual carbon content test values ​​of several groups of samples for inspection and the data of the coke state of the heat transfer oil before the cleaning of the acceptance pipeline, integrate them into a data set to be approved and send them to the residual carbon value approval unit and the oil coke cleaning rate approval unit; The carbon residue value verification unit obtains and processes the data set to be verified, calculates the average carbon residue content by using the carbon residue content detection values ​​in a number of consecutive samples through standard deviation analysis, and then calculates the carbon residue content evaluation coefficient based on the average carbon residue content. The cleaning effect is judged based on the preset carbon residue content evaluation threshold, so as to generate a cleaning qualified signal and send it to the oil coke cleaning rate verification unit or a secondary cleaning signal and send it to the cleaning drive unit; The cleaning drive unit is used to generate a cleaning instruction to the main control center of the heat exchange system after obtaining the secondary cleaning signal, and perform detection and sampling again after the secondary cleaning, and obtain the data set to be approved after the secondary cleaning and send it to the residual carbon value approval unit; After the oil coke cleaning rate verification unit obtains the cleaning qualified signal, it obtains the coke coverage area in the acceptance pipeline after cleaning by visual geometry method, calculates the heat transfer oil coke cleaning rate according to the heat transfer oil coke state data before the acceptance pipeline is cleaned, and sends the heat transfer oil coke cleaning rate to the acceptance result output unit; The acceptance result output unit obtains and processes the thermal oil coke cleaning rate, and determines the thermal oil coke cleaning pass rate according to a preset thermal oil coke cleaning judgment threshold to generate an acceptance pass signal or an acceptance failure signal and output it to the main control center of the heat exchange system.

5. The acceptance system of the online cleaning method of the thermal oil heat exchange system according to claim 4 is characterized in that: The specific process of generating a cleaning qualified signal or a secondary cleaning signal is as follows: S401. Obtain the residual carbon content test values ​​of several groups of samples for inspection: x1, x2, x3, ..., xn, and calculate the average value of the residual carbon content according to the formula Where n is the number of samples to be tested for the determination of residual carbon content; S402. Calculate the residual carbon content evaluation coefficient according to the following formula: The residual carbon content evaluation coefficient is used to measure the residual carbon content in the acceptance pipeline after the reaction heat transfer oil heat exchange system is cleaned. The higher the residual carbon content evaluation coefficient is, the higher the residual carbon content in the acceptance pipeline is, and the worse the cleaning effect is. On the contrary, the lower the residual carbon content evaluation coefficient is, the lower the residual carbon content in the acceptance pipeline is, and the better the cleaning effect is. S403, obtaining a preset residual carbon content evaluation threshold xt: xt=k·σ, where k is a preset proportionality coefficient. If the residual carbon content evaluation coefficient is less than the residual carbon content evaluation threshold, it means that the cleaning effect meets the acceptance standard, and a cleaning qualified signal is generated; If the residual carbon content evaluation coefficient is greater than or equal to the residual carbon content evaluation threshold, it means that the cleaning effect does not meet the acceptance standard and a secondary cleaning signal is generated.

6. The acceptance system for the online cleaning method of a heat transfer oil heat exchange system according to claim 4, characterized in that: The specific process of generating a pass signal or a fail signal is as follows: S501. Obtain the coke coverage area y in the acceptance pipeline after cleaning by visual geometry method, and calculate the heat transfer oil coke cleaning rate B according to the following formula: Where y0 is the coke coverage area in the acceptance pipeline before cleaning, and the thermal oil coke cleaning rate is used to reflect the change in the coke coverage area in the acceptance pipeline before and after cleaning. The higher the thermal oil coke cleaning rate, the better the cleaning effect, and vice versa, the lower the thermal oil coke cleaning rate, the worse the cleaning effect; S502, obtaining a preset thermal oil coke cleaning judgment threshold Bm. If the thermal oil coke cleaning rate is less than the thermal oil coke cleaning judgment threshold, it means that the thermal oil coke cleaning effect does not meet the acceptance standard, and an acceptance failure signal is generated; If the thermal oil coke cleaning rate is greater than or equal to the thermal oil coke cleaning judgment threshold, it means that the thermal oil coke cleaning effect has reached the acceptance standard, and an acceptance pass signal is generated.

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