Method for real-time calculation and evaluation of catalyst-oil ratio of catalytic cracking unit

Abstract

The invention discloses an agent-oil ratio real-time calculation and evaluation method for a catalytic cracking device. The method comprises the following steps: S1, determining an agent-oil ratio real-time calculation model; s2, determining the input quantity of the agent-oil ratio real-time calculation model; s3, obtaining an output result of the agent-oil ratio real-time calculation model; and S4, determining an agent-oil ratio real-time monitoring evaluation standard. According to the catalyst-oil ratio real-time calculation and evaluation method for the catalytic cracking device, real-time operation process parameters of the catalytic cracking device are collected, and key parameters are imported into a catalytic cracking catalyst-oil ratio real-time calculation model, so that the working state of a wing valve of the catalytic cracking device is monitored in real time; and the average catalyst-oil ratio during stable operation of the device is used as an evaluation criterion to evaluate the catalyst-oil ratio in real time, so that a theoretical basis is provided for stable production operation of the catalytic cracking device.

Description

Technical Field

[0001] The invention relates to the field of catalytic cracking unit operating parameter monitoring, and in particular to a catalyst-oil ratio real-time calculation and evaluation method for a catalytic cracking unit. Background Art

[0002] Catalytic cracking is one of the processes in petroleum processing. It is a process in which heavy oil undergoes cracking reaction under the action of heat and catalyst to generate products such as cracked gas, gasoline and diesel. Catalyst-to-oil ratio is the mass ratio of the catalyst circulation amount to the feed amount, and is the main operating parameter of the catalytic cracking unit. When the catalyst-to-oil ratio is large, the raw oil can contact with more catalysts, the carbon deposits on the catalyst are less, and the degree of deactivation is small, thereby improving the conversion rate, but also increasing the coke yield; when the catalyst-to-oil ratio is too small, the proportion of thermal cracking reaction will increase, and the product quality will deteriorate. Therefore, the catalyst-to-oil ratio parameter in the operation of the catalytic cracking unit is one of the key variables for the operation and control of the riser reactor, which directly affects the reaction depth of the feed oil and the distribution of cracking products. Therefore, it is very necessary to conduct on-site online detection of the catalyst-to-oil ratio.

[0003] Catalyst-oil ratio is controlled and regulated by controlling the ratio of catalyst circulation volume to fresh feed volume in catalytic cracking unit. At present, direct observation method, butterfly valve measurement method, switching method, etc. are usually used to measure particle mass flow rate in laboratory circulating fluidized bed units. Venturi tube method is used to measure particle mass flow rate in tube in industrial units, but this method is not suitable for the measurement of catalyst-oil ratio in most catalytic cracking units, and it increases pressure drop.

[0004] For a long time, engineers and technicians have estimated the size of the catalyst circulation volume through the two-device heat balance calculation method, carbon balance method and slide valve pressure drop method, thereby indirectly measuring the catalyst-oil ratio. These methods have the following problems:

[0005] (1) Two-device heat balance calculation method: Some parameters required for calculation cannot be measured in real time by online instruments. The traditional heat balance calculation method can only be used in the process calibration of the device and cannot meet the requirements of real-time control of catalyst circulation volume and catalyst-oil ratio in the process.

[0006] (2) Carbon balance method: Since the carbon content of the regenerated catalyst is not much different from that of the catalyst to be regenerated, the carbon content analysis must be reliable. A slight error or poor sampling representativeness will cause a large fluctuation in the calculation results. Moreover, this method can only obtain results through offline testing and calculation, which has a large time lag and cannot meet the real-time requirements of production monitoring and control.

[0007] (3) Sliding valve pressure drop method: Since the opening of the sliding valve changes during the actual production process, the flow area is difficult to calculate and the reliability of the calculation is poor.

[0008] (4) The dynamic mathematical model of the riser is used to calculate the catalytic cracking reaction heat online to obtain the circulation amount of the catalyst in the catalytic cracking unit. Due to the complexity of the process itself, some model parameters of the dynamic mathematical model of the riser reactor are uncertain, and only approximate values ​​can be estimated and corrected based on actual data.

[0009] Due to the danger and complexity of the FCC reactor production process, under the existing technical conditions, there is no practical and effective method for online detection of the catalyst-oil ratio. It is also impossible to automatically retrieve process parameters, automatically calculate the catalyst-oil ratio, automatically evaluate based on the calculation results, and guide process parameter adjustment. Summary of the invention

[0010] In view of the problems existing in the above-mentioned prior art, the present invention proposes a real-time calculation and evaluation method for the catalyst-oil ratio of a catalytic cracking unit, which has a reasonable design, overcomes the shortcomings of the prior art, and has good effects.

[0011] In order to achieve the above object, the present invention adopts the following technical solution:

[0012] A method for real-time calculation and evaluation of catalyst-oil ratio of a catalytic cracking unit comprises the following steps: S1, determining a real-time calculation model of catalyst-oil ratio;

[0013] S2. Determine the input amount of the real-time calculation model of the agent-oil ratio;

[0014] S3, obtaining the output result of the real-time calculation model of the agent-oil ratio;

[0015] S4. Determine the real-time monitoring and evaluation standard of the agent-oil ratio.

[0016] Furthermore, in step 1, the real-time calculation model of the agent-oil ratio includes the following formula:

[0017] The calculation formula of wet main air volume is: sf =q0·0.97; (1)

[0018] Among them, q0 is the main wind meter quantity;

[0019] The calculation formula of dry main air volume is: gf =q sf 0.98; (2)

[0020] The calculation formula of hydrogen-carbon ratio in flue gas is:

[0021] Where λ is the hydrogen-to-carbon ratio, W CO2 is the carbon dioxide content, W CO is the carbon monoxide content, W O2 is - oxygen content;

[0022] The calculation formula for the amount of charring is:

[0023] Among them, q C is the amount of charcoal burned;

[0024] The calculation formula for the heat released by burning is:

[0025] in, is the heat released when CO2 is generated, Q CO is the heat released by the formation of CO, The heat released to generate H2O;

[0026] The calculation formula of wind consumption index is:

[0027] The calculation formula of coke yield is:

[0028] Among them, q j is the processing volume;

[0029] The calculation formula of smoke to air ratio is:

[0030] Among them, q yq The amount of smoke

[0031] The calculation formula for heating the catalyst is:

[0032] Among them, Q1 is the heat of coke desorption, Q2 is the heat of dry main air heating, Q3 is the heat of main air steam heating, Q4 is the heat of steam heating, Q5 is the heat loss, and Q6 is the external heat;

[0033] The calculation formula for the catalyst circulation amount is:

[0034] Among them, T z is the regeneration temperature, T y is the reaction temperature;

[0035] The formula for calculating the agent-oil ratio is:

[0036] Among them, q hl is the amount of recycled oil, q yj It is the amount of oil slurry recycled.

[0037] Furthermore, in formula (5), Q CO and The calculation formulas are:

[0038]

[0039] Q CO =qC-CO ×1025.8;

[0040]

[0041] in, is the amount of C that produces CO2, q C-CO is the amount of C to generate CO, and the calculation formulas are:

[0042]

[0043]

[0044] Furthermore, in formula (8), the flue gas volume q yq The calculation formula is:

[0045]

[0046] in, is the amount of oxygen in the flue gas, is the amount of nitrogen in the flue gas, The amount of carbon dioxide generated by combustion in flue gas, q CO is the amount of carbon monoxide generated by combustion in flue gas, is the total amount of water vapor; the calculation formulas are:

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] in, is the total amount of oxygen required, To generate water vapor, The water vapor brought by the main wind; the calculation formulas are:

[0053]

[0054]

[0055]

[0056]

[0057] Among them, ρ is the Prevailing wind density, The amount of oxygen required to burn carbon to produce carbon dioxide, The amount of oxygen required to burn carbon to produce carbon monoxide, The amount of oxygen required to produce water for the combustion of hydrogen; the calculation formula is:

[0058]

[0059] Furthermore, in formula (9), the calculation formulas for Q1, Q2, Q3, Q4, Q5, and Q6 are respectively:

[0060] Q1=0.115Q sf ;

[0061] Q2=0.337q gf (T z -T f );

[0062] Q3=0.00603q gf (T z -T f );

[0063] Q4=50(T z -T q );

[0064]

[0065] Q6=0.2389[1000q w ·h z -1000q w ·C·(T s +274.15)];

[0066] Among them, T f is the main air temperature, T q is the steam temperature, q w is the steam generation of the external heat exchanger, h z is the steam enthalpy, C is the relative heat capacity of water, T s is the water phase temperature entering the external heat exchanger.

[0067] Furthermore, in step 2, the main air flow meter quantity q0, the reaction temperature T y , Main air temperature T f , regeneration temperature T z , Steam temperature T q , water phase temperature entering the external heat exchanger T s , processing volume q j , Recycled oil quantity q hl , Oil slurry recycling amount q yj , Steam generation from external heat exchanger q w Get from real-time database;

[0068] The steam enthalpy value h z The heat capacity C compared to water is obtained by calculation, and the calculation formula is:

[0069]

[0070]

[0071] The carbon dioxide content Carbon monoxide content W CO , oxygen content The dry main wind density ρ is obtained through sampling and analysis by on-site sampling personnel and is a constant.

[0072] Further, in step 4, the data obtained from monitoring of a period of normal operation of the catalytic cracking unit is obtained, and the average catalyst-oil ratio is calculated using the following formula:

[0073]

[0074] Among them, n is the number of monitoring times, α is the real-time agent-oil ratio;

[0075] Compare the monitored real-time agent-oil ratio with the average agent-oil ratio. or The evaluation result is abnormal and the agent-oil ratio needs to be adjusted according to the working conditions. The evaluation result is normal.

[0076] Furthermore, the catalyst-oil ratio is changed by adjusting the reaction temperature, the regeneration temperature, the raw material preheating temperature and the amount of the reaction-boosting quenching medium.

[0077] Beneficial technical effects brought by the present invention:

[0078] The present invention provides a method for real-time calculation and evaluation of the catalyst-to-oil ratio of a catalytic cracking unit. By collecting real-time operating process parameters of the catalytic cracking unit, key parameters are introduced into a real-time calculation model of the catalyst-to-oil ratio of the catalytic cracking unit, so as to realize real-time monitoring of the working state of the wing valve of the catalytic cracking unit, and take the average catalyst-to-oil ratio when the unit is running smoothly as a criterion for judging, and evaluate the catalyst-to-oil ratio in real time, so as to provide a theoretical basis for the stable production operation of the catalytic cracking unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 This is a flow chart of real-time evaluation of catalyst-oil ratio in a catalytic cracking unit in an embodiment of the present invention;

[0080] Figure 2 It is a trend diagram of catalyst-oil ratio and catalyst circulation amount in the embodiment proposed by the present invention;

[0081] Figure 3It is the indicator light for evaluating the agent-oil ratio status in the embodiment proposed by the present invention; DETAILED DESCRIPTION

[0082] The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0083] The terms used in this disclosure are for the purpose of describing characteristic embodiments only and are not intended to limit the disclosure. The singular forms "a", "the" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0084] In order to solve the defects and shortcomings in the prior art, a method for real-time calculation and evaluation of the catalyst-oil ratio of a catalytic cracking unit is proposed. The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0085] A method for real-time calculation and evaluation of catalyst-oil ratio of a catalytic cracking unit comprises the following steps:

[0086] S1. Determine the real-time calculation model of the agent-oil ratio;

[0087] ① Solve the wet main air volume, the calculation formula is:

[0088] q sf =q0·0.97; (1)

[0089] Among them, q0 is the main wind meter quantity, Nm 3 / h;

[0090] q sf is the wet main air volume, Nm3 / h;

[0091] ② Solve the dry main air volume, the calculation formula is:

[0092] q gf =q sf 0.98; (2)

[0093] Among them, q gf is the dry main air volume, Nm 3 / h;

[0094] ③ Solve the hydrogen-carbon ratio in flue gas. The formula calculation process is as follows: First, the CO, CO2, and O2 contents in flue gas need to be obtained through daily testing. The main components of flue gas are CO, CO2, O2, N2, and water vapor. The source of H in flue gas is mainly provided by H2O. Since the company's current measurement of flue gas components is mainly based on CO, CO2, and O2 content monitoring, the water vapor content can be estimated through indirect calculation, which is about 56% of the total content of CO, CO2, and O2. Therefore, the hydrogen-carbon ratio can be calculated based on the proportion of water vapor and the proportion of CO and CO2:

[0095]

[0096] Where λ is the hydrogen-to-carbon ratio, dimensionless;

[0097] W CO2 is the carbon dioxide content, %;

[0098] W CO is the carbon monoxide content, %;

[0099] W O2 is — oxygen content, %;

[0100] ④ Solve for the amount of char burnt. The amount of char burnt is obtained by summing the amount of carbon burnt and the amount of hydrogen burnt. The ratio of hydrogen burnt to carbon burnt is equal to the hydrogen-carbon ratio. Therefore, first calculate the amount of carbon burnt. The amount of char burnt can be calculated based on the amount of carbon burnt and the hydrogen-carbon ratio:

[0101]

[0102] Among them, q C is the charcoal burning amount, kg / h;

[0103] q s is the amount of charring, kg / h;

[0104] ⑤ Solve the heat release from burning. The heat release from burning consists of three parts: the heat release from generating CO2, the heat release from generating CO, and the heat release from generating H2O. First, it is necessary to determine the amount of C generated from generating CO2 and the amount of C generated from generating CO:

[0105]

[0106]

[0107] in, is the amount of C to generate CO2, kg / h;

[0108] q C-CO is the amount of C to generate CO, kg / h;

[0109] Under regeneration conditions, the combustion reaction of C generates CO2 and CO. The heat released by each kilogram of carbon to generate CO2 and CO is 33873 kJ / kg and 1025.8 kJ / kg respectively. According to formulas 5-3 and 5-4, the heat released by generating CO2 can be calculated. Heat released by generating CO Q CO :

[0110]

[0111] Q CO =q C-CO ×1025.8; (5-4)

[0112] Secondly, determine the heat released by generating H2O. According to formula (4), the amount of hydrogen burned can be obtained by subtracting the amount of carbon burned from the amount of char burned. The heat released by generating H2O from each kilogram of hydrogen is 119890 kJ / kg, so the heat released by generating H2O can be calculated as:

[0113]

[0114] is the heat released to generate H2O, kJ / h;

[0115] Finally, calculate the heat released by burning Q sf :

[0116]

[0117] Q sf Heat released during charring, kJ / h.

[0118] ⑥ Solve the air consumption index, which is calculated by the ratio of wet main air volume and burnt volume:

[0119]

[0120] ζ is the wind consumption index, dimensionless.

[0121] ⑦ Solve the coking rate, which is calculated from the charring amount and processing amount:

[0122]

[0123] Among them, q j is the processing volume, t / d;

[0124] η is the coking rate, dimensionless.

[0125] ⑧ Solve the smoke-air ratio, which is the ratio of the smoke volume to the main air volume. First, calculate the smoke volume, which is obtained by adding the amount of carbon dioxide generated by carbon combustion, the amount of carbon monoxide generated by carbon combustion, the amount of water vapor, the oxygen content, and the nitrogen content. Since the molar amount of carbon dioxide and carbon monoxide generated by carbon combustion in the smoke is equal to the molar amount of carbon that generates carbon dioxide and carbon monoxide, the amount of carbon dioxide and carbon monoxide generated by combustion in the smoke can be calculated:

[0126]

[0127]

[0128] is the amount of carbon dioxide generated by combustion in flue gas, kg / h;

[0129] q CO It is the amount of carbon monoxide generated by combustion in flue gas, kg / h.

[0130] The total amount of water vapor is obtained by summing the amount of generated water vapor, the amount of water vapor brought in by the main wind, the amount of water vapor brought in by the spent agent, and the amount of loosening and purge steam. The amount of generated water vapor can be calculated based on the amount of hydrogen burned.

[0131]

[0132] Assuming the moisture content in the air is 0.02kg (water) / kg (dry air), the amount of water vapor brought in by the main wind can be calculated.

[0133]

[0134] According to experience, the sum of the water vapor brought into the raw agent and the loosening and purge steam is about 70% of the water brought into the main air, so the total water vapor can be calculated

[0135]

[0136] in, is the amount of water vapor generated, kg / h;

[0137] The amount of water vapor brought in by the main wind, kg / h;

[0138] ρ is the dry main wind density, kg / m 3 ;

[0139] is the total amount of water vapor, kg / h.

[0140] According to experience, the excess oxygen content in flue gas is generally 5%, so the oxygen content in flue gas can be calculated based on the oxygen content required for the reaction:

[0141]

[0142]

[0143]

[0144]

[0145]

[0146] in, —The amount of oxygen required to burn carbon to produce carbon dioxide, kg / h;

[0147] —The amount of oxygen required to burn carbon to produce carbon monoxide, kg / h;

[0148] —The amount of oxygen required to burn hydrogen to produce water, kg / h;

[0149] —Total amount of oxygen required, kg / h;

[0150] —Amount of oxygen in flue gas, kg / h;

[0151] The nitrogen content in the flue gas is the total amount of oxygen required by the flue gas To obtain:

[0152]

[0153] is the amount of nitrogen in the flue gas, kg / h.

[0154] In summary, the flue gas volume q can be calculated yq for:

[0155]

[0156]

[0157] q yq is the flue gas volume, kg / h;

[0158] ψ is the smoke-wind ratio, dimensionless.

[0159] ⑨ Solve the heat of heating catalyst, which is obtained by adding the heat of coke desorption, the heat of dry main air temperature rise, the heat of main air temperature rise, the heat of steam temperature rise, heat loss, and external heat. The heat solution formula for each part is as follows:

[0160] Q1=0.115Q sf; (9-1)

[0161] Q2=0.337q gf (T z -T f ); (9-2)

[0162] Q3=0.00603q gf (T z -T f ); (9-3)

[0163] Q4=50(T z -T q ); (9-4)

[0164]

[0165] Q6=0.2389[1000q w ·h z -1000q w ·C·(T s +274.15)]; (9-6)

[0166]

[0167] Wherein, Q1 is the heat of coke desorption, Kcal / h;

[0168] Q2 is the dry main air temperature rise heat, Kcal / h;

[0169] Q3 is the main air steam heating heat, Kcal / h;

[0170] Q4 is the steam heating heat, Kcal / h;

[0171] Q5 is heat loss, Kcal / h;

[0172] Q6 is external heat, Kcal / h;

[0173] Q7 is the heat of heating catalyst, Kcal / h;

[0174] T z is the regeneration temperature, °C;

[0175] T y is the reaction temperature, ℃

[0176] T f is the main air temperature, °C;

[0177] T q is the steam temperature, °C;

[0178] T s is the water phase temperature entering the external heat exchanger, °C;

[0179] q w is the steam generation capacity of the external heat exchanger, t / h;

[0180] h z is the steam enthalpy, kJ / kg;

[0181] C is the specific heat capacity of water, kJ / (kg·K).

[0182] ⑩ Solve for the catalyst circulation amount, the calculation formula is:

[0183]

[0184] Among them, q X is the catalyst circulation amount, t / h;

[0185] Solve the solvent-oil ratio, the calculation formula is:

[0186]

[0187] Among them, q hl is the amount of recycled oil;

[0188] q yj It is the amount of oil slurry recycled.

[0189] From the above, it can be seen that formulas (1) to (11) constitute the real-time calculation model of the agent-oil ratio.

[0190] S2. Determine the input amount of the real-time calculation model of the agent-oil ratio;

[0191] ①Determine the steam enthalpy:

[0192] The steam enthalpy and relative heat capacity of water are calculated using the following formula:

[0193] h z =-0.002719×T q 2 +2.036×T q +2499;(12)

[0194] Among them, h z is the enthalpy value, kJ / kg;

[0195] T q is the steam temperature, ℃.

[0196] ② Determine the relative heat capacity of water:

[0197] C=0.000009×T s 2 -0.0007×T s +4.1955; (13)

[0198] Where C is the specific heat capacity of water, kJ / (kg·K);

[0199] T s is the water phase temperature, ℃.

[0200] ③Determine the content of carbon dioxide, carbon monoxide and oxygen:

[0201] Since the carbon dioxide, carbon monoxide and oxygen content in the flue gas need to be sampled and analyzed by on-site sampling personnel before the data can be updated, it will limit the real-time calculation of the agent-oil ratio. Since the carbon dioxide, carbon monoxide and oxygen content in the flue gas do not change much, the data after each sampling is set as a fixed value for a period of time until the next data update. For example: at 12:00 on May 2, the results of the analysis of the carbon dioxide, carbon monoxide and oxygen content in the flue gas were 12.86%, 0.5%, and 3.88% respectively; at 12:00 on May 4, the results of the analysis of the carbon dioxide, carbon monoxide and oxygen content in the flue gas were 12.49%, 0.1%, and 4.01% respectively. Then, between 12:00 on May 2 and 12:00 on May 4, the carbon dioxide, carbon monoxide and oxygen contents of the flue gas when the real-time calculation of the oil-to-gas ratio program was running were: 12.86%, 0.5% and 3.88%; after 12:00 on May 4 and before the next detection and analysis, the carbon dioxide, carbon monoxide and oxygen contents of the flue gas when the real-time calculation of the oil-to-gas ratio program was running were: 12.49%, 0.1% and 4.01%.

[0202] Main air flow q0, reaction temperature T y , Main air temperature T f , regeneration temperature T z , Steam temperature T q , water phase temperature entering the external heat exchanger T s , processing volume q j , Recycled oil quantity q hl , Oil slurry recycling amount q yj , Steam generation from external heat exchanger q w Get from real-time database;

[0203] S3, obtaining the output result of the real-time calculation model of the agent-oil ratio;

[0204] S4. Determine the real-time monitoring and evaluation standard of the agent-oil ratio.

[0205] The data monitored during a month of normal and stable operation of the device is selected to calculate the average agent-oil ratio of the device, and then the real-time agent-oil ratio monitored is compared with the average agent-oil ratio. (The average agent-oil ratio can be calculated by the operator according to the operating status of the device and updated to the model for agent-oil ratio evaluation.)

[0206]

[0207] in, is the average agent-oil ratio, dimensionless;

[0208] n is the number of monitoring times, n≮50, which is the number of collection times in one month;

[0209] α is the real-time agent-oil ratio, dimensionless.

[0210] Table 1 Evaluation criteria for real-time monitoring of agent-oil ratio

[0211]

[0212] If the evaluation result is "abnormal fluctuation, focus on", the agent-oil ratio needs to be adjusted according to the working conditions. The agent-oil ratio can be changed by adjusting the following process parameters.

[0213] 1) Reaction temperature. When other conditions remain unchanged, increasing the reaction temperature will increase the heat required for the reaction, and the reaction heat is provided by the regenerated catalyst. The increase in the catalyst circulation volume will increase the catalyst-oil ratio. Through calculation, when other conditions remain unchanged, the catalyst-oil ratio increases by about 0.1-0.2 units for every 1°C increase in reaction temperature.

[0214] 2) Regeneration temperature. When other conditions remain unchanged, increasing the regeneration temperature increases the heat brought to the reaction by a certain amount of catalyst, reduces the circulation of the catalyst and lowers the catalyst-oil ratio. Through calculation, when other conditions remain unchanged, for every 3°C increase in regeneration temperature, the catalyst-oil ratio decreases by about 0.1 unit.

[0215] 3) Raw material preheating temperature. When other conditions remain unchanged, lowering the raw material preheating temperature increases the heat required for the reaction, and the regeneration catalyst circulation volume needs to be increased, thereby increasing the catalyst-oil ratio. Through calculation, when other conditions remain unchanged, for every 10°C increase in the raw material preheating temperature, the catalyst-oil ratio decreases by about 0.1 units.

[0216] 4) The amount of quenching medium in the reaction riser. When the quenching medium is injected into the riser, it needs to absorb a large amount of heat to vaporize and crack. The catalyst-oil mixture at the injection point is cooled. In order to maintain the set reaction temperature, the catalyst circulation volume must be increased, thereby increasing the catalyst-oil ratio.

[0217] The catalyst-oil ratio of the catalytic cracking unit is evaluated in conjunction with specific examples. Figure 1 As shown, the following steps are included:

[0218] 1) Call the real-time parameters (main air meter, reaction temperature, main air temperature, regeneration temperature, steam temperature, water phase temperature entering the external heat exchanger, processing volume, recycled oil volume, slurry recycled volume, steam generation volume of the external heat exchanger) and test parameters (flue gas carbon dioxide content, carbon monoxide content, oxygen content) required for model calculation in the DCS real-time database and LIMS laboratory analysis database; in addition, call real-time data to calculate some input parameters required by the model (steam enthalpy, water relative heat capacity); finally, input the constant value dry main air density;

[0219] 2) Bringing the input parameters into the real-time calculation model of catalytic cracking agent oil ratio for calculation;

[0220] In this embodiment, the model input items are summarized as shown in Table 2:

[0221] Table 2 Summary of input items for the real-time calculation model of agent-oil ratio

[0222]

[0223]

[0224] 3) The intermediate parameters and key parameters calculated by the obtained model (intermediate parameters: wet main air volume, dry main air volume, hydrogen-carbon ratio, charring amount, charring amount, C amount of CO2 generated, C amount of CO generated, heat release of CO2 generated, heat release of CO generated, heat release of H2O generated, heat release of charring, air consumption index, charring rate, amount of carbon dioxide generated by combustion in flue gas, amount of carbon monoxide generated by combustion in flue gas, amount of water vapor generated, amount of water vapor brought into the main air, total amount of water vapor, amount of oxygen required for carbon combustion to generate carbon dioxide, amount of oxygen required for carbon combustion to generate carbon monoxide, amount of oxygen required for hydrogen combustion to generate water, total amount of oxygen required, amount of oxygen in flue gas, amount of nitrogen in flue gas, flue-air ratio, flue gas volume, coke desorption heat, dry main air heating heat, main air heating heat, steam heating heat, heat loss, external heat, catalyst heating heat; key parameters: agent-oil ratio, catalyst circulation amount)

[0225] In this embodiment, the model output items are summarized as shown in Table 3:

[0226] Table 3 Summary of output items of the real-time calculation model of agent-oil ratio

[0227]

[0228]

[0229]

[0230] 4) According to the agent-oil ratio change diagram, Figure 2As shown in the figure, the data monitored during the normal and stable operation of the unit for one month are selected to calculate the average catalyst-oil ratio of the unit, and then the monitored real-time catalyst-oil ratio is compared with the average catalyst-oil ratio. The 126 catalyst-oil ratio data calculated by the catalyst-oil ratio model during the normal and stable operation of the catalytic cracking unit from March to April are selected to calculate the average catalyst-oil ratio.

[0231] The data are shown in Table 4:

[0232] Table 4 Calculated values ​​of catalyst-oil ratio of a catalytic cracking unit from March to April

[0233]

[0234]

[0235]

[0236]

[0237] Get the average agent-oil ratio for:

[0238]

[0239] α—is the real-time agent-oil ratio, dimensionless.

[0240] Table 5 Evaluation criteria for real-time monitoring of agent-oil ratio

[0241]

[0242] According to the evaluation criteria in Table 5, the calculated agent-oil ratio of 6.4 is substituted into the evaluation result of the agent-oil ratio at this moment, which is "normal". Figure 3 At this point, there is no need to adjust the production and operation parameters of the device.

[0243] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A method for real-time calculation and evaluation of catalyst-oil ratio in a catalytic cracking unit, characterized in that: The following steps are involved: S1. Determine the real-time calculation model of the agent-oil ratio; S2. Determine the input amount of the real-time calculation model of the agent-oil ratio; S3, obtaining the output result of the real-time calculation model of the agent-oil ratio; S4. Determine the real-time monitoring and evaluation standard of the agent-oil ratio.

2. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 1, characterized in that: In step 1, the real-time calculation model of the agent-oil ratio includes the following formula: The calculation formula of wet main air volume is: sf =q0·0.97; (1) Among them, q0 is the main wind meter quantity; The calculation formula of dry main air volume is: gf =q sf 0.98; (2) The calculation formula of hydrogen-carbon ratio in flue gas is: Where λ is the hydrogen-to-carbon ratio, W CO2 is the carbon dioxide content, W CO is the carbon monoxide content, W O2 is - oxygen content; The calculation formula for the amount of charring is: Among them, q C is the amount of charcoal burned; The calculation formula for the heat released by burning is: in, is the heat released when CO2 is generated, Q CO is the heat released by the formation of CO, The heat released to generate H2O; The calculation formula of wind consumption index is: The calculation formula of coke yield is: Among them, q j is the processing volume; The calculation formula of smoke to air ratio is: Among them, q yq The amount of smoke The calculation formula for heating the catalyst is: Among them, Q1 is the heat of coke desorption, Q2 is the heat of dry main air heating, Q3 is the heat of main air steam heating, Q4 is the heat of steam heating, Q5 is the heat loss, and Q6 is the external heat; The calculation formula for the catalyst circulation amount is: Among them, T z is the regeneration temperature, T y is the reaction temperature; The formula for calculating the agent-oil ratio is: Among them, q hl is the amount of recycled oil, q yj It is the amount of oil slurry recycled.

3. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 2, characterized in that: In formula (5), Q CO and The calculation formulas are: Q CO =q C-CO ×1025.8; in, is the amount of C that produces CO2, q C-CO is the amount of C that produces CO.

4. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 3, characterized in that: and q C-CO The calculation formulas are:

5. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 2, characterized in that: In formula (8), the flue gas volume q yq The calculation formula is: in, is the amount of oxygen in the flue gas, is the amount of nitrogen in the flue gas, The amount of carbon dioxide generated by combustion in flue gas, q CO is the amount of carbon monoxide generated by combustion in flue gas, is the total amount of water vapor.

6. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 5, characterized in that: Said q CO and The calculation formulas are: in, is the total amount of oxygen required, To generate water vapor, The amount of water vapor brought in by the dominant wind.

7. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 6, characterized in that: Said q C-CO , and The calculation formulas are: Where ρ is the dry main wind density, The amount of oxygen required to burn carbon to produce carbon dioxide, The amount of oxygen required to burn carbon to produce carbon monoxide, The amount of oxygen required to burn hydrogen to produce water.

8. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 7, characterized in that: Said The calculation formula is:

9. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 2, characterized in that: In formula (9), the calculation formulas for Q1, Q2, Q3, Q4, Q5, and Q6 are: Q1=0.115Q sf ; Q2=0.337q gf (T z -T f ); Q3=0.00603q gf (T z -T f ); Q4=50(T z -T q ); Q6=0.2389[1000q w ·h z -1000q w ·C·(T s +274.15)]; Among them, T f is the main air temperature, T q is the steam temperature, q w is the steam generation of the external heat exchanger, h z is the steam enthalpy, C is the relative heat capacity of water, T s is the water phase temperature entering the external heat exchanger.

10. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 2, characterized in that: In step 2, the main air flow meter q0, reaction temperature T y , Main air temperature T f , regeneration temperature T z , Steam temperature T q , water phase temperature entering the external heat exchanger T s , processing volume q j , Recycled oil quantity q hl , Oil slurry recycling amount q yj , Steam generation from external heat exchanger q w Get from real-time database; The steam enthalpy value h z The heat capacity C compared to water is obtained by calculation, and the calculation formula is: h z =-0.002719×T q 2 +2.036×T q +2499; C=0.000009×T s 2 -0.0007×T s +4.1955; The carbon dioxide content W CO2 、Carbon monoxide content W CO , oxygen content W O2 The dry main wind density ρ is obtained through sampling and analysis by on-site sampling personnel and is a constant.

11. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 4, characterized in that: In step 4, the data obtained from monitoring of a period of normal operation of the catalytic cracking unit is obtained, and the average catalyst-oil ratio is calculated using the following formula: Among them, n is the number of monitoring times, α is the real-time agent-oil ratio; Compare the monitored real-time agent-oil ratio with the average agent-oil ratio. or The evaluation result is abnormal and the agent-oil ratio needs to be adjusted according to the working conditions. The evaluation result is normal.

12. A method for real-time calculation and evaluation of catalyst-oil ratio for catalytic cracking according to claim 5, characterized in that: The catalyst-oil ratio can be changed by adjusting the reaction temperature, regeneration temperature, raw material preheating temperature and the amount of reaction-boosting quenching medium.

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