A hydrogen consumption device analysis method for hydrogen network considering light hydrocarbon impurities

Abstract

The present application relates to a kind of hydrogen network hydrogen-consuming device analysis method considering light hydrocarbon impurities, by extracting the process data in the working process of hydrogen-consuming device and the gas product property flow and liquid product property flow of hydrogenation reactor output, the chemical hydrogen consumption of hydrogen-consuming device is calculated, the composition of light hydrocarbon product and the light hydrocarbon product flow in hydrogen-consuming device are obtained, strict gas-liquid phase equilibrium simulation is carried out to the separator of hydrogen-consuming device, the hydrogen purity and flow of hydrogen-containing stream in hydrogen-consuming device are calculated, and by constantly adjusting the new hydrogen flow entering hydrogen-consuming device and the external discharge hydrogen flow discharged from hydrogen-consuming device, so that hydrogen-consuming device reaches the fixed hydrogenation reactor inlet condition maintained.The hydrogen purity variation and flow variation of hydrogen-containing stream in hydrogen-consuming device are accurately calculated under the distribution of different light hydrocarbon impurities in hydrogen-containing gas stream, and the accuracy of simulation calculation of hydrogen-consuming device is improved.

Description

Technical Field

[0001] This invention relates to the field of refinery hydrogen network management, and more particularly to an analytical method for hydrogen network hydrogen consumption devices that takes into account light hydrocarbon impurities. Background Technology

[0002] As refineries impose increasingly stringent requirements on crude oil reprocessing while simultaneously demanding higher quality standards for products derived from degraded crude oil, higher demands are being placed on hydrogen management in refineries. How to allocate hydrogen resources within a hydrogen network has become a crucial issue.

[0003] In his 1999 doctoral dissertation, *Analysis and Design of Refinery Hydration Systems*, Aleves proposed the concepts of hydrogen sources and hydrogen traps. He pointed out that in a hydrogen network, the flow rates and purity of hydrogen sources and traps can be extracted from the network's operational data, yielding corresponding two-dimensional hydrogen composite curves and hydrogen surplus curves, which can then be used to determine the pinch points of the hydrogen network. These two-dimensional hydrogen composite curves and hydrogen surplus curves can be used to assess the feasibility of a hydrogen network and set hydrogen recovery targets. To achieve the hydrogen recovery targets set using this graphical method, linear programming is generally required to solve the hydrogen network model.

[0004] To address some limitations in hydrogen network models, Liu proposed a method for designing hydrogen networks through superstructure optimization in his 2002 doctoral dissertation, "HYDROGENINTEGRATION IN OIL REFINERIES," and used the MINLP method to integrate hydrogen production and purification devices into the hydrogen network.

[0005] However, existing analytical methods for hydrogen network management have shortcomings: current analyses of hydrogen-consuming devices in hydrogen networks are based on the assumption that the partial pressure of hydrogen at the reactor inlet (hydrogen purity) and the hydrogen-to-oil ratio remain constant, thus assuming that the composition and flow rate of the gas at the reactor outlet remain constant. This assumption neglects the presence of hydrogen-containing gases such as CH4, C2H6, C3H8, and C4H in the hydrogen-containing gas stream. 10 The impact of different light hydrocarbon impurity distributions on the hydrogen network was not considered. All impurities were simplified to methane (CH4) or a single impurity. That is, the gas in the hydrogen network was simplified to a binary mixture of hydrogen (H2) and methane (CH4). However, the effects of the above-mentioned different impurity distributions on the hydrogen-to-oil ratio and hydrogen partial pressure of the hydrogen-consuming unit, as well as the effects on the gas-liquid phase separation after the reaction, were not taken into account. This resulted in a change in the calculated circulating hydrogen purity of the hydrogen-consuming unit compared with the actual situation, which significantly reduced the calculation accuracy of the hydrogen-consuming unit and even caused a large deviation between the optimization results and the actual production process. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an analytical method for hydrogen network hydrogen consumption devices that takes into account light hydrocarbon impurities, in light of the prior art.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problem is: an analysis method for a hydrogen network hydrogen consumption device considering light hydrocarbon impurities, characterized by comprising the following steps:

[0008] Step 1: Extract process data from the hydrogen-consuming unit during operation. The process data includes the liquid feed flow rate and properties at the inlet of the hydrogen-consuming unit, as well as the flow rate and properties of fresh hydrogen and recycled hydrogen. The properties of the liquid feed include the density and distillation range of the liquid product, and the properties of the fresh hydrogen and recycled hydrogen include their gas composition.

[0009] Step 2: Extract the properties and flow rates of the gaseous product and the liquid product output from the hydrogenation reactor of the hydrogen-consuming unit; wherein, the gaseous product properties include the gaseous product composition, and the liquid product properties include the density and distillation range of the liquid product;

[0010] Step 3: Based on the difference between the inlet and outlet materials extracted in Step 1 and Step 2, calculate the chemical hydrogen consumption of the hydrogen-consuming device, and calculate the composition and flow rate of the light hydrocarbon products generated in the hydrogen-consuming device.

[0011] Step 4: Change the new hydrogen conditions of the hydrogen-consuming device, and adjust the internal operation of the hydrogenation reactor under the changed new hydrogen conditions to maintain fixed hydrogenation reactor inlet conditions; wherein, changing the new hydrogen conditions means changing the hydrogen purity and / or light hydrocarbon impurity composition of the new hydrogen stream, and fixed hydrogenation reactor inlet conditions mean that the hydrogen-to-oil ratio and hydrogen partial pressure entering the hydrogenation reactor are kept constant.

[0012] Step 5: Based on the chemical hydrogen consumption of the hydrogen-consuming device obtained in Step 3 and the composition and flow rate of the light hydrocarbon products generated in the hydrogen-consuming device, calculate the flow rate and composition of the product at the outlet of the hydrogenation reactor of the hydrogen-consuming device under different new hydrogen conditions.

[0013] Step 6: Based on the flow rate and composition of the product at the outlet of the hydrogenation reactor obtained in Step 5, perform gas-liquid phase balance calculations on the flash separator in the hydrogen-consuming device to obtain the hydrogen purity and flow rate of the hydrogen-containing stream in the hydrogen-consuming device; wherein, the hydrogen-containing stream in the hydrogen-consuming device is the gas phase product stream at the outlet of the flash separator and the circulating hydrogen and exhaust hydrogen streams generated by the diversion of the gas phase product stream.

[0014] Step 7: Continuously adjust the flow rate of new hydrogen entering the hydrogen-consuming device and the flow rate of hydrogen discharged from the hydrogen-consuming device to ensure that the hydrogen-consuming device reaches the fixed inlet conditions of the hydrogenation reactor maintained in Step 4.

[0015] Improvedly, in the analysis method of hydrogen network hydrogen consumption device considering light hydrocarbon impurities, the gas-liquid phase balance calculation in step 6 adopts a thermodynamic property calculation method applicable to hydrogen-containing systems.

[0016] Alternatively, in the analytical method for hydrogen network hydrogen-consuming devices that takes into account light hydrocarbon impurities, the thermodynamic property calculation method is the Peng-Robinson method, the Grayson-Streed method, or the Chao-Seader method.

[0017] Furthermore, in the analytical method for hydrogen network hydrogen-consuming devices that considers light hydrocarbon impurities, the calculation process for the chemical hydrogen consumption of the hydrogen-consuming device in step 3 is as follows:

[0018] Step a1: Calculate the product of the gas flow rate of the mixed gas entering the hydrogenation reactor and the hydrogen purity in the mixed gas;

[0019] Step a2: Calculate the product of the gas flow rate of the mixed gas at the outlet of the hydrogenation reactor and the hydrogen purity in the mixed gas;

[0020] Step a3: The difference between the product obtained in step a1 and the product obtained in step a2 is taken as the chemical hydrogen consumption of the hydrogen-consuming device.

[0021] Furthermore, in the analytical method for hydrogen network hydrogen-consuming devices that considers light hydrocarbon impurities, the flow rate calculation process for the light hydrocarbon products generated within the hydrogen-consuming device in step 3 is as follows:

[0022] Step b1: Calculate the product of the gas flow rate of the mixed gas entering the hydrogenation reactor and the purity of each light hydrocarbon component in the mixed gas;

[0023] Step b2: Calculate the product of the gas flow rate of the mixed gas at the outlet of the hydrogenation reactor and the purity of each light hydrocarbon component in the mixed gas;

[0024] Step b3: The difference between the product obtained in step b2 and the product obtained in step b1 is taken as the amount of light hydrocarbons generated by the hydrogen-consuming device.

[0025] Compared with existing technologies, the advantages of this invention are as follows: The hydrogen network hydrogen-consuming device analysis method considering light hydrocarbon impurities in this invention calculates the chemical hydrogen consumption of the hydrogen-consuming device by extracting process data during the operation of the hydrogen-consuming device and the gas and liquid product property flow rates output from the hydrogenation reactor. This yields the light hydrocarbon product composition and flow rate within the hydrogen-consuming device. Furthermore, a rigorous gas-liquid phase equilibrium simulation is performed on the separator of the hydrogen-consuming device to calculate the hydrogen purity and flow rate of the hydrogen-containing stream within the device. By continuously adjusting the new hydrogen flow rate entering the hydrogen-consuming device and the outflow hydrogen flow rate, the hydrogen-consuming device maintains the fixed inlet conditions of the hydrogenation reactor. Thus, considering the distribution of different light hydrocarbon impurities in the hydrogen-containing gas stream, accurate calculations of the changes in hydrogen purity and flow rate of the hydrogen-containing stream within the hydrogen-consuming device are achieved, improving the accuracy of the simulation calculations for the hydrogen-consuming device. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart of the analysis method for a hydrogen network hydrogen consumption device considering light hydrocarbon impurities in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of a hydrogen network hydrogen consumption device in an embodiment of the present invention. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0029] This embodiment provides an analytical method for a hydrogen network hydrogen-consuming device that considers light hydrocarbon impurities. The hydrogen network hydrogen-consuming device (or hydrogen-consuming device) is a diesel hydrotreating unit. Specifically, see [link to documentation]. Figure 1 As shown, the analysis method for hydrogen network hydrogen consumption devices considering light hydrocarbon impurities in this embodiment includes the following steps 1 to 7:

[0030] Step 1: Extract process data from the inlet of the hydrogen-consuming unit during operation; the process data includes liquid feed flow rate, liquid feed properties, and the flow rate and properties of fresh hydrogen and recycled hydrogen; the liquid feed properties include the density and distillation range of the liquid product, and the properties of fresh hydrogen and recycled hydrogen include gas composition;

[0031] In this embodiment, the hydrogen-consuming device includes a hydrogenation reactor 1, a high-pressure flash separator 2 (or high-pressure separator), a component separator 3 for removing H2S and NH3, and a purge gas device 4. The input end of the hydrogenation reactor 1 is connected to the output end of the gas after mixing with the circulating hydrogen input end 11 and the fresh hydrogen input end 12. The input end of the hydrogenation reactor 1 is also connected to a liquid feedstock input end 14. The hydrogenation reactor 1 has a chemical hydrogen consumption output end 15. The gas-liquid mixture output end 13 of the hydrogenation reactor 1 is connected to the input end 21 of the high-pressure flash separator 2 via a cooler 16. The high-pressure flash separator... The gas output terminal 22 of the device 2 is connected to the gas input terminal 31 of the component separator 3. The liquid product output terminal 23 of the high-pressure flash separator 2 outputs the liquid product after high-pressure separation. The component separator 3 has a sulfur gas output terminal 32 that outputs H2S and NH3 and a desulfurized gas output terminal 33. The purge gas device 4 has a purge gas output terminal 41 and a hydrogen output terminal 42. The hydrogen output from the desulfurized gas output terminal 33 is discharged through the purge gas device 4, and the hydrogen output from the hydrogen output terminal 42 is used as recycled hydrogen. The high-pressure flash separator is a type of flash separator.

[0032] For example, in this embodiment, the process data of the diesel hydrotreating unit was extracted, and the extracted process data is shown in Table 1.

[0033]

[0034] Table 1

[0035] Step 2: Extract the properties and flow rates of the gaseous product and the liquid product output from the hydrogenation reactor of the hydrogen-consuming unit; wherein, the gaseous product properties include the gaseous product composition, and the liquid product properties include the density and distillation range of the liquid product;

[0036] Step 3: Based on the inlet and outlet material differences extracted in Steps 1 and 2, calculate the chemical hydrogen consumption of the hydrogen-consuming device, and calculate the composition and flow rate of the light hydrocarbon products generated in the hydrogen-consuming device; specifically, in this embodiment, the calculation process of the chemical hydrogen consumption of the hydrogen-consuming device, which is a diesel hydrotreating device, is as follows: Steps a1 to a3:

[0037] Step a1: Calculate the product of the gas flow rate of the mixed gas entering the hydrogenation reactor and the hydrogen purity in the mixed gas;

[0038] Step a2: Calculate the product of the gas flow rate of the mixed gas at the outlet of the hydrogenation reactor and the hydrogen purity in the mixed gas;

[0039] Step a3: The difference between the product obtained in step a1 and the product obtained in step a2 is taken as the chemical hydrogen consumption of the hydrogen-consuming device.

[0040] The calculation process for the flow rate of light hydrocarbon products generated in the hydrogen-consuming unit is as follows: steps b1 to b3:

[0041] Step b1: Calculate the product of the gas flow rate of the mixed gas entering the hydrogenation reactor and the purity of each light hydrocarbon component in the mixed gas;

[0042] Step b2: Calculate the product of the gas flow rate of the mixed gas at the outlet of the hydrogenation reactor and the purity of each light hydrocarbon component in the mixed gas;

[0043] Step b3: The difference between the product obtained in step b2 and the product obtained in step b1 is taken as the amount of light hydrocarbons generated by the hydrogen-consuming device.

[0044] Table 2 shows the basic operating data of the hydrogen-consuming device in this embodiment.

[0045]

[0046] Table 2 shows the chemical hydrogen consumption and light hydrocarbon generation of the hydrogen-consuming device in this embodiment. See Table 3 for details.

[0047] Flow rate, Nm3 / hr Chemical hydrogen consumption Light hydrocarbons are generated <![CDATA[H2]]> 17878.6 - <![CDATA[CH4]]> - 352.7 <![CDATA[C2H6]]> - 122.1 <![CDATA[C3H8]]> - 474.7 <![CDATA[i-C4H 10 ]]> - 616.0 <![CDATA[n-C4H 10 ]]> - 299.6 <![CDATA[i-C5H 12 ]]> - 108.2 <![CDATA[n-C5H 12 ]]> - 38.1

[0048] Table 3

[0049] Step 4: Change the new hydrogen conditions of the hydrogen-consuming unit, and adjust the internal operation of the hydrogenation unit under the changed new hydrogen conditions to maintain fixed inlet conditions of the hydrogenation reactor. Changing the new hydrogen conditions means changing the hydrogen purity and / or light hydrocarbon impurity composition of the new hydrogen stream. Fixed inlet conditions of the hydrogenation reactor mean that the hydrogen-to-oil ratio and hydrogen partial pressure (i.e., hydrogen purity) entering the hydrogenation reactor are both kept constant. Different new hydrogen conditions mean that the new hydrogen stream has different hydrogen purity and / or light hydrocarbon impurity composition. See Table 4 for details in this embodiment.

[0050] Hydrogen byproducts of catalytic reforming purity(%) Chemical composition, mol% <![CDATA[H2O]]> 0 <![CDATA[H2S]]> 0 <![CDATA[H2]]> 93.90 <![CDATA[CH4]]> 1.80 <![CDATA[C2H6]]> 1.80 <![CDATA[C3H8]]> 1.40 <![CDATA[i-C4H 10 ]]> 0.30 <![CDATA[n-C4H 10 ]]> 0.30 <![CDATA[i-C5H 12 ]]> 0.25 <![CDATA[n-C5H 12 ]]> 0.25

[0051] Table 4

[0052] Step 5: Based on the chemical hydrogen consumption of the hydrogen-consuming device obtained in Step 3 and the composition and flow rate of the light hydrocarbon products generated in the hydrogen-consuming device, calculate the flow rate and composition of the product at the outlet of the hydrogenation reactor of the hydrogen-consuming device under different new hydrogen conditions.

[0053] Step 6: Based on the flow rate and composition of the reactor outlet product obtained in Step 5, perform gas-liquid phase equilibrium calculations on the flash separator in the hydrogen-consuming unit to obtain the hydrogen purity and flow rate of the hydrogen-containing stream in the hydrogen-consuming unit. The hydrogen-containing stream in the hydrogen-consuming unit consists of the gas phase product stream at the flash separator outlet, as well as the circulating hydrogen and exhaust hydrogen streams generated by the diversion of this gas phase product stream. The gas-liquid phase equilibrium calculation here requires the use of thermodynamic property calculation methods suitable for hydrogen-containing systems. This example uses the Grayson-Streed thermodynamic method; however, common thermodynamic methods such as the Peng-Robinson method or the Chao-Seader method can also be used as needed.

[0054] Step 7: Continuously adjust the fresh hydrogen flow rate and exhaust hydrogen flow rate of the hydrogen-consuming device to affect the corresponding circulating hydrogen flow rate and hydrogen purity, so that the hydrogen-consuming device reaches the fixed inlet conditions of the hydrogenation reactor maintained in Step 4. Specifically, for the diesel hydrogenation device in this embodiment, Table 5 shows the changes in hydrogen purity and flow rate of the hydrogen-containing stream under varying fresh hydrogen conditions.

[0055]

[0056] Table 5

[0057] After performing steps 1 to 7 above, and comparing the data in Tables 2 and 5, it can be seen that, under the condition of changing the composition of the new hydrogen and the distribution of impurities, in order to maintain the same hydrogen-to-oil ratio and hydrogen partial pressure (i.e., hydrogen purity), that is, to maintain the fixed inlet conditions of the hydrogenation reactor, the circulating hydrogen purity increased from 89.86% to 90.35%, the circulating hydrogen flow rate decreased from 106310.4 Nm3 / hr to 86800 Nm3 / hr, the high-pressure exhaust flow rate increased from 1916.8 Nm3 / hr to 20812.1 Nm3 / hr, and the new hydrogen flow rate increased from 20095 Nm3 / hr to 39605.4 Nm3 / hr; the inlet hydrogen purity of the hydrogenation reactor remained unchanged at 91.46%.

[0058] Starting from the same basic operating conditions, the calculation results of the hydrogen network hydrogen consumption device analyzed using traditional methods are shown in Table 6. These calculation results can be compared with the calculation results of the new method proposed in this invention.

[0059]

[0060] Table 6

[0061] As shown above, when considering the use of fresh hydrogen containing impurities, i.e., when considering the distribution of light hydrocarbon impurities in the hydrogen gas stream, for a hydrogen-consuming device, if the inlet hydrogen-to-oil ratio and hydrogen partial pressure of the hydrogenation reactor are kept constant (i.e., maintaining fixed inlet conditions of the hydrogenation reactor), changes in the purity of the fresh hydrogen will lead to changes in both the purity and flow rate of the circulating hydrogen. In this embodiment, the calculated fresh hydrogen flow rates are 39605.4 Nm3 / hr and 50061.5 Nm3 / hr, respectively, showing a significant difference. This indicates that traditional analytical methods that do not consider light hydrocarbon impurities will lead to excessive hydrogen consumption and hydrogen loss. When analyzed within a hydrogen network, this will affect the pinch points of the entire hydrogen network, further impacting the results of hydrogen network optimization.

[0062] Although preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An analytical method for hydrogen network hydrogen consumption devices considering light hydrocarbon impurities, characterized in that, Includes the following steps: Step 1: Extract process data from the inlet of the hydrogen-consuming unit during operation; the process data includes liquid feed flow rate, liquid feed properties, and the flow rate and properties of fresh hydrogen and recycled hydrogen; the liquid feed properties include the density and distillation range of the liquid product, and the properties of fresh hydrogen and recycled hydrogen include gas composition; Step 2: Extract the properties and flow rates of the gaseous product and the liquid product output from the hydrogenation reactor of the hydrogen-consuming unit; wherein, the gaseous product properties include the gaseous product composition, and the liquid product properties include the density and distillation range of the liquid product; Step 3: Based on the difference between the inlet and outlet materials extracted in Step 1 and Step 2, calculate the chemical hydrogen consumption of the hydrogen-consuming device, and calculate the composition and flow rate of the light hydrocarbon products generated in the hydrogen-consuming device. Step 4: Change the new hydrogen conditions of the hydrogen-consuming device, and adjust the internal operation of the hydrogenation reactor under the changed new hydrogen conditions to maintain the fixed inlet conditions of the hydrogenation reactor; wherein, changing the new hydrogen conditions means changing the hydrogen purity and / or light hydrocarbon impurity composition of the new hydrogen stream, and the fixed inlet conditions of the hydrogenation reactor mean that the hydrogen-to-oil ratio and hydrogen partial pressure entering the hydrogenation reactor are kept constant. Step 5: Based on the chemical hydrogen consumption of the hydrogen-consuming device obtained in Step 3 and the composition and flow rate of the light hydrocarbon products generated in the hydrogen-consuming device, calculate the flow rate and composition of the product at the outlet of the hydrogenation reactor of the hydrogen-consuming device under different new hydrogen conditions. Step 6: Based on the flow rate and composition of the reactor outlet product obtained in Step 5, perform gas-liquid phase balance calculations on the flash separator in the hydrogen-consuming device to obtain the hydrogen purity and flow rate of the hydrogen-containing stream in the hydrogen-consuming device; wherein, the hydrogen-containing stream in the hydrogen-consuming device is the gas phase product stream at the outlet of the flash separator and the circulating hydrogen and exhaust hydrogen streams generated by the diversion of the gas phase product stream. Step 7: Adjust the new hydrogen flow rate and the vented hydrogen flow rate so that the hydrogen-consuming device reaches the fixed hydrogenation reactor inlet conditions maintained in Step 4.

2. The analytical method for hydrogen network hydrogen consumption devices considering light hydrocarbon impurities according to claim 1, characterized in that, The gas-liquid phase equilibrium calculation in step 6 employs a thermodynamic property calculation method applicable to hydrogen-containing systems.

3. The analytical method for hydrogen network hydrogen consumption devices considering light hydrocarbon impurities according to claim 2, characterized in that, The thermodynamic property calculation method is either the Peng-Robinson method, the Grayson-Streed method, or the Chao-Streed method.

4. The analytical method for hydrogen network hydrogen consumption devices considering light hydrocarbon impurities according to claim 1, characterized in that, In step 3, the calculation process for the chemical hydrogen consumption of the hydrogen-consuming device is as follows: Step a1: Calculate the product of the gas flow rate of the mixed gas entering the hydrogenation reactor and the hydrogen purity in the mixed gas; Step a2: Calculate the product of the gas flow rate of the mixed gas at the outlet of the hydrogenation reactor and the hydrogen purity in the mixed gas; Step a3: The difference between the product obtained in step a1 and the product obtained in step a2 is taken as the chemical hydrogen consumption of the hydrogen-consuming device.

5. The analytical method for hydrogen network hydrogen consumption devices considering light hydrocarbon impurities according to claim 1, characterized in that, The process for calculating the flow rate of the light hydrocarbon products generated in the hydrogen-consuming device is as follows: steps b1 to b3: Step b1: Calculate the product of the gas flow rate of the mixed gas entering the hydrogenation reactor and the purity of each light hydrocarbon component in the mixed gas; Step b2: Calculate the product of the gas flow rate of the mixed gas at the outlet of the hydrogenation reactor and the purity of each light hydrocarbon component in the mixed gas; Step b3: The difference between the product obtained in step b2 and the product obtained in step b1 is taken as the amount of light hydrocarbons generated by the hydrogen-consuming device.

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