A method and system for hydraulic drive compressor design for natural gas recovery

Abstract

The application provides a hydraulic drive compressor design method and system for natural gas recovery, which automatically completes total pressure ratio planning, staged exhaust temperature prediction and key conversion of gas flow demand into theoretical stroke volume of each stage according to input process parameters; then, the theoretical stroke volume is analyzed into a theoretical cylinder bore, and the size is rounded according to engineering specifications, and then the actual stroke volume after rounding is immediately reviewed through reverse calculation, forming a design closed loop ensuring the unity of performance and manufacturability; finally, according to the determined mechanical motion parameters, the flow, displacement and driving power of the hydraulic pump are automatically matched and calculated, and the optimization design of the oil tank volume and the inner diameter of each stage of oil pipe is completed, so as to encapsulate the multi-disciplinary design knowledge into a data-driven automatic assembly line from process demand to complete engineering scheme.

Description

Technical Field

[0001] This application relates to the field of industrial software and computer-aided design technology, and in particular to a design method and system for a hydraulically driven compressor for natural gas recovery. Background Technology

[0002] 1. The urgent need for efficient resource utilization and emission control in the modern natural gas industry. In the distribution or pressure regulating stations of long-distance natural gas pipelines, it is usually necessary to throttle and depressurize the incoming high-pressure gas to ensure stable downstream pressure. This process results in a significant waste of pressure potential energy and may be accompanied by process venting or trace methane escape, causing energy loss and violating current stringent carbon reduction and environmental protection policies. Therefore, developing efficient and reliable low-pressure methane recovery and pressurization technologies to repressurize pipeline gas that might otherwise be vented or inefficiently utilized and inject it into the high-pressure pipeline network or liquefy it for storage is of great significance for improving the operating efficiency of the entire pipeline system, reducing greenhouse gas emissions, and creating economic benefits.

[0003] 2. The challenge of pressure energy recovery is prevalent in natural gas transmission and distribution systems. In pipeline pressure regulation and distribution stages, traditional throttling and depressurization processes result in the dissipation of a large amount of high-pressure gas energy as heat, potentially accompanied by methane escape. This not only causes significant energy economic losses but also contradicts global sustainable development goals of energy conservation and emission reduction. Therefore, developing efficient and reliable gas pressurization and recovery technologies to reintegrate dispersed, low-grade pressure resources into the energy cycle system has become an important direction for technological innovation in the field of energy engineering.

[0004] 3. Hydraulically driven reciprocating compressors are a unique technological approach that has emerged in this context. Compared with traditional electric motor-driven reciprocating compressors, hydraulic drive systems transmit power through oil, offering advantages such as a wide speed range, strong load adaptability, smooth start-stop, and easy overload protection. They are particularly suitable for distribution station environments with fluctuating operating conditions or remote automatic control. Summary of the Invention

[0005] This application provides a design method and system for a hydraulically driven compressor for natural gas recovery, which solves the problem of low compressor design efficiency in the prior art. It encapsulates multidisciplinary design knowledge into a data-driven automated production line that goes directly from process requirements to a complete engineering solution.

[0006] To achieve the above objectives, the technical solution of this application embodiment is as follows: In a first aspect, embodiments of this application provide a design method for a hydraulically driven compressor for natural gas recovery, the method comprising: Step 1: Based on the primary inlet pressure and secondary outlet pressure of the compressor, determine the total pressure ratio required for compressor operation; Step 2: Based on the intake temperature and preset pressure ratio of each stage, and combined with the thermodynamic model of the gas polymorphic process, determine the exhaust temperature of each stage of the compressor; the preset pressure ratio is obtained based on the total pressure ratio. Step 3: Based on the specific inlet conditions and target outlet conditions of each stage of the compressor, convert the mass-conserved compression process requirements into stroke volume; Step 4: Based on the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length, and in conjunction with the cylinder geometric volume formula, determine the theoretical cylinder inner diameter of the compressor in reverse. Step 5: Determine the actual stroke volume by combining the rounded-up theoretical cylinder inner diameter with geometric formulas; Step 6: Determine the total oil flow rate required to drive the entire actuator based on the operating parameters of the hydraulic drive piston, and determine the theoretical displacement required by the hydraulic pump based on the total oil flow rate and the selected drive motor speed. Step 7: Based on the total oil flow rate required by the hydraulic system and the preset maximum working pressure, determine the theoretical power output of the hydraulic pump; Step 8: Based on the total flow rate of all hydraulic pumps and the recommended ratio between the tank volume and the total flow rate, obtain the theoretical volume of the required tank. Step 9: Based on the allowable flow rate of the oil corresponding to the pipeline type and the flow rate required by the hydraulic system, determine the minimum theoretical pipe diameter that satisfies the allowable flow rate of the oil by combining fluid mechanics formulas.

[0007] In one possible implementation, step 1 includes: determining the total pressure ratio using the following formula: ;in, The total pressure ratio, This represents a level one import pressure. This creates secondary export pressure. Step 2 includes determining the exhaust temperature at each stage using the following formula: ;in, For the first Level of intake air temperature, To preset the pressure ratio, For the first The exhaust temperature of the stage, It is a process index.

[0008] In one possible implementation, step 3 includes: determining the travel volume using the following formula: , ; in, This is the theoretical volumetric flow rate under intake conditions. For the theoretical flow volume, For standard flow, Due to export pressure, For the outlet temperature, For operating frequency, For volumetric efficiency, Z Compression factor, subscript Indicates the standard state.

[0009] In one possible implementation, step 4 includes: determining the theoretical cylinder inner diameter using the following formula: ;in, For the first The theoretical stroke volume required for the stage, To preset the number of cylinders, For piston stroke, This is the theoretical cylinder inner diameter.

[0010] In one possible implementation, step 5 includes: determining the actual travel volume using the following formula: Among them, due to limitations in machining and standard parts, the theoretical inner diameter Rounded to the actual usable value. , This refers to the actual travel volume. To preset the number of cylinders, This refers to the piston stroke.

[0011] In one possible implementation, step 6 includes: determining the total oil flow rate using the following formula: : ;in, The effective working area of ​​the piston in a single-hydraulic-driven cylinder. The average piston speed The number of cylinders working simultaneously. This represents the total oil flow rate; The theoretical displacement is determined using the following formula: ;in, To select the drive motor speed, For pump volumetric efficiency, This is the theoretical displacement.

[0012] In one possible implementation, step 7 includes: determining the theoretical power using the following formula: ;in, The preset maximum working pressure of the hydraulic system, This represents the total oil flow rate required by the hydraulic system. The total efficiency of the hydraulic pump. This represents the theoretical power.

[0013] In one possible implementation, step 8 includes determining the theoretical volume using the following formula: ; in, The sum of the hydraulic pump flow rates. This is an empirical coefficient, usually taken as... .

[0014] In one possible implementation, step 9 includes: determining the minimum pipe inner diameter using the following formula: ;in, For the allowable flow rate of the oil, In order to pass through traffic, This is the theoretical minimum inner diameter.

[0015] Secondly, embodiments of this application provide a hydraulically driven compressor design system for natural gas recovery, used to execute the method described in the first aspect. The system includes: a thermodynamic performance determination module, a mechanical structure parameter determination module, and a hydraulic drive system determination module; the thermodynamic performance determination module is connected to the hydraulic drive system determination module through the mechanical structure parameter determination module. The thermodynamic performance determination unit is used to determine the total pressure ratio required for compressor operation based on the first-stage inlet pressure and the second-stage outlet pressure of the compressor; to determine the exhaust temperature of each stage of the compressor based on the inlet temperature of each stage and the preset pressure ratio, combined with the thermodynamic model of the gas polymorphism process; the preset pressure ratio is obtained based on the total pressure ratio; and to convert the mass-conserving compression process requirements into stroke volume according to the specific inlet conditions and target outlet state of each stage of the compressor. The mechanical structure parameter determination unit is used to determine the theoretical cylinder inner diameter of the compressor in reverse, based on the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length, combined with the geometric volume formula of the cylinder; and to determine the actual stroke volume by combining the rounded theoretical cylinder inner diameter with the geometric formula. The hydraulic drive system determination module is used to determine the total oil flow rate required to drive the entire actuator based on the operating parameters of the hydraulic drive piston, and to determine the theoretical displacement required by the hydraulic pump based on the total oil flow rate and the selected drive motor speed; to determine the theoretical power output required by the hydraulic pump based on the total oil flow rate required by the hydraulic system and the preset maximum working pressure; to obtain the theoretical volume of the required oil tank based on the sum of the flow rates of all hydraulic pumps and the recommended ratio between the oil tank volume and the total flow rate; and to determine the minimum theoretical pipe diameter that satisfies the allowable oil flow rate based on the allowable oil flow rate corresponding to the pipeline type and the flow rate required by the hydraulic system, combined with fluid mechanics formulas.

[0016] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: By encapsulating the compressor parameter design process into a data-driven automated pipeline that goes directly from process requirements to complete engineering solutions through a highly integrated three-stage automated process chain, the compressor design efficiency is improved. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a design method for a hydraulically driven compressor for natural gas recovery, provided as an embodiment of this application; Figure 2 This is a block diagram of a hydraulically driven compressor design system for natural gas recovery, provided as an embodiment of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] In the description of the embodiments of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0021] Figure 1 A flowchart illustrating a design method for a hydraulically driven compressor for natural gas recovery, provided as an embodiment of this application. Figure 1 As shown, the method may include the following steps.

[0022] Step 1: Based on the primary inlet pressure and secondary outlet pressure of the compressor, determine the total pressure ratio required for compressor operation.

[0023] Step 2: Based on the intake temperature and preset pressure ratio of each stage, and combined with the thermodynamic model of the gas polymorphic process, determine the exhaust temperature of each stage of the compressor; the preset pressure ratio is obtained based on the total pressure ratio.

[0024] Step 3: Based on the specific inlet conditions and target outlet conditions of each stage of the compressor, convert the mass-conserved compression process requirements into stroke volume.

[0025] Step 4: Based on the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length, and in conjunction with the cylinder geometric volume formula, determine the theoretical cylinder inner diameter of the compressor in reverse.

[0026] Step 5: Determine the actual stroke volume by combining the rounded-up theoretical cylinder inner diameter with geometric formulas.

[0027] Step 6: Based on the operating parameters of the hydraulic drive piston, determine the total oil flow rate required to drive the entire actuator, and based on the total oil flow rate and the selected drive motor speed, determine the theoretical displacement required by the hydraulic pump.

[0028] Step 7: Based on the total oil flow rate required by the hydraulic system and the preset maximum working pressure, determine the theoretical power output of the hydraulic pump.

[0029] Step 8: Based on the total flow rate of all hydraulic pumps and the recommended ratio between the tank volume and the total flow rate, obtain the theoretical volume of the required tank.

[0030] Step 9: Based on the allowable flow rate of the oil corresponding to the pipeline type and the flow rate required by the hydraulic system, determine the minimum theoretical pipe diameter that satisfies the allowable flow rate of the oil by combining fluid mechanics formulas.

[0031] According to the above technical solution, the compressor parameter design process can be encapsulated into a data-driven automated production line that goes directly from process requirements to complete engineering solutions through a highly integrated three-stage automated process chain, thereby improving compressor design efficiency.

[0032] In one possible implementation, step 1 includes determining the total pressure ratio using the following formula: ;in, The total pressure ratio, This represents a level one import pressure. The secondary outlet pressure is used. Step 2 includes determining the exhaust temperature for each stage using the following formula: ;in, For the first Level of intake air temperature, To preset the pressure ratio, For the first The exhaust temperature of the stage, It is a process index.

[0033] In one possible implementation, step 3 includes: determining the stroke volume using the following formula: , ;in, This is the theoretical volumetric flow rate under intake conditions. For the theoretical flow volume, For standard flow, Due to export pressure, For the outlet temperature, For operating frequency, For volumetric efficiency, Z Compression factor, subscript Indicates the standard state.

[0034] In one possible implementation, step 4 includes: determining the theoretical cylinder inner diameter using the following formula: ;in, For the first The theoretical stroke volume required for the stage, To preset the number of cylinders, For piston stroke, This is the theoretical cylinder inner diameter.

[0035] In one possible implementation, step 5 includes: determining the actual travel volume using the following formula: Among them, due to limitations in machining and standard parts, the theoretical inner diameter Rounded to the actual usable value. , This refers to the actual travel volume. To preset the number of cylinders, This refers to the piston stroke.

[0036] In one possible implementation, step 6 includes: determining the total oil flow rate using the following formula: : ;in, The effective working area of ​​the piston in a single-hydraulic-driven cylinder. The average piston speed The number of cylinders working simultaneously. The total oil flow rate; the theoretical displacement is determined using the following formula: ;in, To select the drive motor speed, For pump volumetric efficiency, This is the theoretical displacement.

[0037] In one possible implementation, step 7 includes determining the theoretical power using the following formula: ;in, The preset maximum working pressure of the hydraulic system, This represents the total oil flow rate required by the hydraulic system. The total efficiency of the hydraulic pump. This represents the theoretical power.

[0038] In one possible implementation, step 8 includes: determining the theoretical volume using the following formula: ;in, The sum of the hydraulic pump flow rates. This is an empirical coefficient, usually taken as... .

[0039] In one possible implementation, step 9 includes: determining the minimum pipe inner diameter using the following formula: ;in, For the allowable flow rate of the oil, In order to pass through traffic, This is the theoretical minimum inner diameter.

[0040] The following is combined with Figure 1 The workflow of this application is described.

[0041] 1. Determination of the core thermodynamic parameters of the compressor. By inputting the two most basic process boundary conditions—the primary inlet pressure and the secondary outlet pressure—the system can automatically calculate the total pressure ratio required for compressor operation. The calculation formula is: Among them, the primary import pressure is: Secondary export pressure is: .

[0042] This calculation is the logical starting point for the entire compressor thermodynamic design. Its results directly determine the energy consumption level and the rationality of the stage configuration in the compression process, and provide key macroscopic indicators for evaluating the overall system performance and energy consumption.

[0043] 2. Precise calculation of staged exhaust temperature. Input the intake temperature of each stage and the preset pressure ratio (usually derived from the overall pressure ratio). Based on a thermodynamic model of gas polytropic processes, the exhaust temperatures of the first and second stages will be calculated separately. The formula is: Among them, the first Intake temperature of stage: Preset pressure ratio: ;No. i Stage exhaust temperature: Process index: .

[0044] This step is crucial because the exhaust temperature directly affects the safety of compressor operation (preventing overheating), material selection, the effectiveness of the lubrication system, and the design requirements of the interstage cooler. It is a core verification step to ensure that the equipment operates reliably within the thermodynamic boundary.

[0045] 3. Volumetric flow rate conversion and stroke volume determination throughout the compressor stages. The core logic of this step lies in accurately converting the mass-conserving compression process requirements into the core parameter guiding mechanical design—stroke volume—based on the specific inlet conditions and target outlet state of each stage. The formula is: , Among them, the theoretical volumetric flow rate under intake conditions is: Theoretical stroke volume: Standard flow rate: Export pressure: Outlet temperature: Operating frequency: Based on the real gas equation of state and volumetric efficiency calculate; Z Compression factor, subscript Indicates the standard state.

[0046] For the first stage, based on the input standard state inlet flow rate, target outlet pressure and temperature, and operating frequency, the standard flow rate is first converted to the actual inlet state using the real gas state equation and thermodynamic principles. Then, the actual volumetric flow rate of the first stage outlet is calculated according to the outlet conditions. Finally, the theoretical stroke volume required to achieve this flow rate is calculated. This process is the primary bridge connecting external process requirements and internal mechanical structure design.

[0047] For the second and higher levels (not the first level), the calculation logic is consistent with the first level, but it starts from the basis of inter-stage cooling and pressure connection. The outlet state of the previous level (after cooling adjustment) is used as the inlet condition of the current level. The actual inlet pressure, temperature and the target outlet pressure of this level are input. Based on this specific inlet condition, a volume and flow conversion process similar to that of the first level but with different parameter starting points is executed to determine the theoretical stroke volume required for each subsequent level.

[0048] This unified and coherent process ensures that the core dimensions of each stage cylinder in multi-stage compression are precisely matched to its unique and actual inlet conditions. This not only achieves coordinated operation and flow connection between stages, avoiding "bottleneck" or "overcapacity" problems caused by design mismatches, but also fundamentally guarantees the consistency of the overall machine design and the optimization of overall operating efficiency.

[0049] 4. Conversion from Volumetric Requirements to Critical Dimensions – Cylinder Bore. Once the required "stroke volume" (i.e., the volume of gas processed per piston stroke) for a given compression stage is determined, the formula is: Among them, the first Theoretical stroke volume required for stage: The preset number of cylinders is Piston stroke: The required theoretical cylinder inner diameter is calculated in reverse based on the cylinder geometry formula. .

[0050] By entering the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length here, the required cylinder inner diameter can be calculated in reverse based on the cylinder's geometric volume formula. This result serves as a direct basis for machining and component selection, transforming abstract thermodynamic parameters (volume) into concrete, manufacturable physical dimensions.

[0051] 5. Verification from Manufacturing Dimensions to Actual Performance – Actual Stroke Volume. Since the theoretical cylinder inner diameter is usually rounded based on standard tubing or machining specifications, the actual size will inevitably deviate from the theoretical value. Input the rounded cylinder inner diameter here, and recalculate the "actual stroke volume" using the geometric formula. The formula is as follows: Due to limitations in machining and standard parts, the theoretical inner diameter needs to be... Rounded to the actual usable value. Immediately re-determine the actual travel volume. Number of cylinders: Piston stroke: .

[0052] This verification step is crucial because it accurately assesses the changes in processing capacity caused by dimensional rounding, ensuring that the physical structure of the final manufactured compressor accurately meets or slightly covers the initial thermodynamic performance requirements, thus completing the design loop from "design dimensions" back to "performance verification".

[0053] 6. Determining the actuator's required power source specifications—hydraulic system flow rate and pump displacement. This step converts the compressor's mechanical motion parameters into the hydraulic system's fluid requirements. Inputting the effective area of ​​a single hydraulic drive piston, its average operating speed, and the number of cylinders operating simultaneously, the total hydraulic flow rate (L / min) required to drive the entire actuator is first calculated. Subsequently, combined with the selected drive motor speed, the theoretical displacement (ml / r) required by the hydraulic pump is further calculated. The formula is: Total oil flow rate required by the drive system Among them, the effective working area of ​​the piston in a single-fluid-driven cylinder is: Piston average speed: Number of cylinders operating simultaneously: .

[0054] Theoretical displacement of hydraulic pump Among them, the selected drive motor speed is: Pump volumetric efficiency: .

[0055] This step is the direct basis for the selection and design of the hydraulic power unit (pump station), ensuring that the hydraulic pump can provide sufficient flow to drive the compressor piston to operate stably at a preset speed.

[0056] 7. After determining the required flow rate and the maximum working pressure preset or calculated by the system, inputting these two key parameters will determine the theoretical power output of the hydraulic pump. The formula is: The maximum working pressure of the hydraulic system is: Total hydraulic fluid flow rate: ; Total efficiency of the hydraulic pump: .

[0057] This power value is the core basis for selecting the power level of the matching drive motor (or engine) in the future. It ensures that the power source can provide enough energy to overcome the maximum load generated by gas compression and leaves room for system pressure loss and efficiency margin, thereby ensuring the reliability and stability of the entire hydraulic drive system under extreme working conditions.

[0058] 8. Determining the oil tank volume aims to determine the appropriate size of the oil tank based on the total circulating oil demand of the hydraulic system. Input the total flow rate of all hydraulic pumps, and based on recommended ratios of oil tank volume to total flow rate from engineering experience (e.g., the effective oil tank volume is typically several times the total flow rate), the required theoretical oil tank volume will be determined. The formula is: Among them, the sum of hydraulic pump flow rates: Empirical coefficient: , usually take This process ensures the minimum residence time required for oil cooling, contaminant settling, and air separation.

[0059] This step ensures that the oil tank has sufficient capacity to dissipate heat, settle contaminants, separate air from the oil, and accommodate oil flowing back when the system stops. It is fundamental to maintaining the cleanliness of the hydraulic oil, temperature stability, and long-term reliable operation of the system.

[0060] 9. Determining the inner diameter of the oil pipe is to achieve efficient and stable flow within the hydraulic system. Based on the pipeline type (such as high-pressure pipeline, return oil pipeline, suction oil pipeline), the recommended allowable oil flow rate from the engineering specifications is input. Combined with the known system flow rate, fluid mechanics formulas are used to calculate the minimum theoretical pipe diameter that meets the flow rate condition.

[0061] The formula is: Among them, the allowable flow velocity of the target pipeline is: Through traffic: Calculate the theoretical minimum inner diameter: .

[0062] The core objective of this process is to optimize pipeline design: too small a diameter leads to excessively high flow rates, resulting in increased pressure loss, higher oil temperature, and noise; too large a diameter increases unnecessary costs, weight, and oil filling volume. This step ensures a balance between energy transfer efficiency and economic benefits in the pipeline system.

[0063] According to the above technical solution, the compressor parameter design process can be encapsulated into a data-driven automated production line that goes directly from process requirements to complete engineering solutions through a highly integrated three-stage automated process chain, thereby improving compressor design efficiency.

[0064] The workflow of this application will be described below with reference to embodiments.

[0065] Suppose a natural gas distribution station needs to design a hydraulically driven reciprocating compressor to recover excess methane gas at a pressure of 5 MPa (absolute pressure, the same below) and a temperature of 15°C, and then pressurize it to 9 MPa before reinjecting it into the pipeline network. The design requirement is a recovered gas volume of 500 Nm³ / h. This is used as the basic process parameter input into the system: primary inlet pressure... Secondary export pressure Standard flow rate First-stage intake temperature .

[0066] First, according to the formula Calculate the total pressure ratio to obtain Based on the principle of equal work and considering cooling efficiency, the system automatically plans for two-stage compression and recommends a pressure ratio allocation of: one stage... Level 2 Subsequently, the system invokes the multivariate process model (taking the methane process index). Calculate the exhaust temperature: First stage exhaust temperature: .

[0067] Second stage exhaust temperature (assuming interstage cooling to 15°C): .

[0068] The system performs flow conversion based on the real gas law.

[0069] Level 1: The system is based on standard traffic. Inlet pressure (5 MPa, 15℃) and outlet pressure ( ), combined with the obtained compression factor (such as ) and preset volumetric efficiency First, the standard flow rate is converted into the theoretical volumetric flow rate under intake conditions. Then according to the formula Calculate the theoretical stroke volume. Set the operating frequency. Calculated .

[0070] Second stage: The system uses the first stage outlet conditions (8.05 MPa, 43.71℃ after cooling) as the second stage inlet conditions (setting the temperature after cooling to 15℃). Combined with the target outlet pressure of 9.0 MPa, similar flow rate and volume calculations are performed to obtain the theoretical stroke volume of the second stage. .

[0071] Cylinder bore calculation: For the first stage, input Set single cylinder ( Piston stroke The system uses the formula Calculations were performed to obtain the theoretical cylinder inner diameter. .

[0072] According to standard pipe specifications, Rounding to the nearest whole number .

[0073] According to the formula Recalculate to obtain the actual travel volume. The system automatically verifies. and The deviation (approximately -2.0%) is considered within the allowable tolerance (e.g., ±5%), indicating the design is feasible. Similarly, the theoretical inner diameter is calculated in the second stage. Rounded to After review The deviation is approximately -6.6%, which meets the requirements.

[0074] Determining hydraulic flow rate and pump displacement: Setting the effective area of ​​the hydraulic cylinder piston. (Corresponding to a diameter of 80mm), average piston speed unilateral work ( According to the formula Calculate the required oil flow rate. Select motor speed Pump volumetric efficiency Calculate the theoretical displacement of the hydraulic pump According to the product manual, an axial piston pump with a displacement of 50 ml / r was selected.

[0075] Hydraulic pump power determination: The system calculates the maximum working pressure based on cylinder force analysis. Take the overall pump efficiency. According to the formula Calculate the required power. Based on this, a 45 kW explosion-proof motor was selected.

[0076] Since there is only one main pump, Take the empirical coefficient. According to the formula Calculation yields the theoretical volume of the fuel tank. Considering the structure, the fuel tank is designed with an effective volume of 350 L.

[0077] For the main pressure pipeline, take the allowable flow rate. ,flow .

[0078] According to the formula The theoretical inner diameter was calculated. Based on this, a standard seamless steel pipe with an outer diameter of 22mm and an inner diameter of 18mm was selected.

[0079] According to the above technical solution, the compressor parameter design process can be encapsulated into a data-driven automated production line that goes directly from process requirements to complete engineering solutions through a highly integrated three-stage automated process chain, thereby improving compressor design efficiency.

[0080] Figure 2 This is a block diagram of a hydraulically driven compressor design system for natural gas recovery, provided as an embodiment of this application. (Refer to...) Figure 2 The system is used to execute the above-mentioned design method for a hydraulically driven compressor for natural gas recovery. The system may include: a thermodynamic performance determination module, a mechanical structure parameter determination module, and a hydraulic drive system determination module; the thermodynamic performance determination module is connected to the hydraulic drive system determination module through the mechanical structure parameter determination module.

[0081] This thermodynamic performance determination unit is used to determine the total pressure ratio required for compressor operation based on the first-stage inlet pressure and the second-stage outlet pressure of the compressor; based on the inlet temperature of each stage and the preset pressure ratio, combined with the thermodynamic model of the gas polymorphic process, it determines the exhaust temperature of each stage of the compressor; the preset pressure ratio is allocated based on the total pressure ratio; according to the specific inlet conditions and target outlet conditions of each stage of the compressor, the mass-conserving compression process requirements are converted into stroke volume.

[0082] The mechanical structure parameter determination unit is used to determine the theoretical cylinder inner diameter of the compressor in reverse, based on the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length, combined with the cylinder geometric volume formula; the actual stroke volume is determined by rounding up the theoretical cylinder inner diameter and combining it with the geometric formula.

[0083] The hydraulic drive system determination module is used to determine the total hydraulic flow rate required to drive the entire actuator based on the operating parameters of the hydraulic drive piston, and to determine the theoretical displacement required by the hydraulic pump based on the total hydraulic flow rate and the selected drive motor speed; to determine the theoretical power output required by the hydraulic pump based on the total hydraulic flow rate required by the hydraulic system and the preset maximum working pressure; to obtain the theoretical volume of the required oil tank based on the sum of the flow rates of all hydraulic pumps and the recommended ratio between the oil tank volume and the total flow rate; and to determine the minimum theoretical pipe diameter that meets the allowable flow rate of the hydraulic fluid according to the pipeline type and the flow rate required by the hydraulic system, combined with fluid mechanics formulas.

[0084] According to the above technical solution, the compressor parameter design process can be encapsulated into a data-driven automated production line that goes directly from process requirements to complete engineering solutions through a highly integrated three-stage automated process chain, thereby improving compressor design efficiency.

[0085] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0086] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A design method for a hydraulically driven compressor for natural gas recovery, characterized in that, The method includes: Step 1: Based on the primary inlet pressure and secondary outlet pressure of the compressor, determine the total pressure ratio required for compressor operation; Step 2: Based on the intake temperature and preset pressure ratio of each stage, and combined with the thermodynamic model of the gas polymorphic process, determine the exhaust temperature of each stage of the compressor; the preset pressure ratio is obtained based on the total pressure ratio. Step 3: Based on the specific inlet conditions and target outlet conditions of each stage of the compressor, convert the mass-conserved compression process requirements into stroke volume; Step 4: Based on the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length, and in conjunction with the cylinder geometric volume formula, determine the theoretical cylinder inner diameter of the compressor in reverse. Step 5: Determine the actual stroke volume by combining the rounded-up theoretical cylinder inner diameter with geometric formulas; Step 6: Determine the total oil flow rate required to drive the entire actuator based on the operating parameters of the hydraulic drive piston, and determine the theoretical displacement required by the hydraulic pump based on the total oil flow rate and the selected drive motor speed. Step 7: Based on the total oil flow rate required by the hydraulic system and the preset maximum working pressure, determine the theoretical power output of the hydraulic pump; Step 8: Based on the total flow rate of all hydraulic pumps and the recommended ratio between the tank volume and the total flow rate, obtain the theoretical volume of the required tank. Step 9: Based on the allowable flow rate of the oil corresponding to the pipeline type and the flow rate required by the hydraulic system, determine the minimum theoretical pipe diameter that satisfies the allowable flow rate of the oil by combining fluid mechanics formulas.

2. The method according to claim 1, characterized in that, Step 1 includes determining the total pressure ratio using the following formula: ;in, The total pressure ratio, This represents a level one import pressure. This creates secondary export pressure. Step 2 includes determining the exhaust temperature at each stage using the following formula: ;in, For the first Level of intake air temperature, To preset the pressure ratio, For the first The exhaust temperature of the stage, It is a process index.

3. The method according to claim 1, characterized in that, Step 3 includes determining the travel volume using the following formula: , ; in, This is the theoretical volumetric flow rate under intake conditions. For the theoretical flow volume, For standard flow, Due to export pressure, For the outlet temperature, For operating frequency, For volumetric efficiency, Z Compression factor, subscript Indicates the standard state.

4. The method according to claim 1, characterized in that, Step 4 includes determining the theoretical cylinder inner diameter using the following formula: ;in, For the first The theoretical stroke volume required for the stage, To preset the number of cylinders, For piston stroke, This is the theoretical cylinder inner diameter.

5. The method according to claim 1, characterized in that, Step 5 includes determining the actual travel volume using the following formula: Among them, due to limitations in machining and standard parts, the theoretical inner diameter Rounded to the actual usable value. , This refers to the actual travel volume. To preset the number of cylinders, This refers to the piston stroke.

6. The method according to claim 1, characterized in that, Step 6 includes determining the total oil flow rate using the following formula: : ;in, This represents the effective working area of ​​the piston in a single-fluid-driven cylinder. The average piston speed, The number of cylinders working simultaneously. This represents the total oil flow rate; The theoretical displacement is determined using the following formula: ;in, To select the drive motor speed, For pump volumetric efficiency, This is the theoretical displacement.

7. The method according to claim 1, characterized in that, Step 7 includes determining the theoretical power using the following formula: ;in, The preset maximum working pressure of the hydraulic system, This represents the total oil flow rate required by the hydraulic system. The total efficiency of the hydraulic pump. This represents the theoretical power.

8. The method according to claim 1, characterized in that, Step 8 includes determining the theoretical volume using the following formula: ; in, The sum of the hydraulic pump flow rates. This is an empirical coefficient, usually taken as... .

9. The method according to claim 1, characterized in that, Step 9 includes determining the minimum pipe inner diameter using the following formula: ;in, For the allowable flow rate of the oil, In order to pass through traffic, This is the theoretical minimum inner diameter.

10. A hydraulically driven compressor design system for natural gas recovery, characterized in that, The system is used to perform the method according to any one of claims 1-9, comprising: a thermodynamic performance determination module, a mechanical structure parameter determination module, and a hydraulic drive system determination module; the thermodynamic performance determination module is connected to the hydraulic drive system determination module through the mechanical structure parameter determination module. The thermodynamic performance determination unit is used to determine the total pressure ratio required for compressor operation based on the first-stage inlet pressure and the second-stage outlet pressure of the compressor; to determine the exhaust temperature of each stage of the compressor based on the inlet temperature of each stage and the preset pressure ratio, combined with the thermodynamic model of the gas polymorphism process; the preset pressure ratio is obtained based on the total pressure ratio; and to convert the mass-conserving compression process requirements into stroke volume according to the specific inlet conditions and target outlet state of each stage of the compressor. The mechanical structure parameter determination unit is used to determine the theoretical cylinder inner diameter of the compressor in reverse, based on the theoretical stroke volume, the preset number of cylinders, and the selected piston stroke length, combined with the geometric volume formula of the cylinder; and to determine the actual stroke volume by combining the rounded theoretical cylinder inner diameter with the geometric formula. The hydraulic drive system determination module is used to determine the total oil flow rate required to drive the entire actuator based on the operating parameters of the hydraulic drive piston, and to determine the theoretical displacement required by the hydraulic pump based on the total oil flow rate and the selected drive motor speed; to determine the theoretical power output required by the hydraulic pump based on the total oil flow rate required by the hydraulic system and the preset maximum working pressure; to obtain the theoretical volume of the required oil tank based on the sum of the flow rates of all hydraulic pumps and the recommended ratio between the oil tank volume and the total flow rate; and to determine the minimum theoretical pipe diameter that satisfies the allowable oil flow rate based on the allowable oil flow rate corresponding to the pipeline type and the flow rate required by the hydraulic system, combined with fluid mechanics formulas.

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