A hydrogen energy utilization gas blending system and hydrogen and natural gas ratio control method

Abstract

The present invention discloses a hydrogen energy utilization gas blending system and a hydrogen and natural gas ratio control method, which relates to the field of renewable energy utilization. The source hydrogen enters the gas mixing pipeline through an inlet ball valve, a pneumatic shut-off valve, and a filter, and the hydrogen flow is measured by a flow meter. The hydrogen dosage is adjusted by a regulating valve and then enters the gas mixing device through an outlet ball valve; the source natural gas enters the gas mixing pipeline through an inlet ball valve, a filter shut-off valve, and after pressure regulation and metering, it passes through a regulating valve to the outlet ball valve and enters the gas mixing device; the detection equipment at the gas mixing outlet controls the opening of the regulating valve on the natural gas and hydrogen pipelines together with the flow value after temperature and pressure compensation, controls the hydrogen volume flow, performs online adjustment and automatic following of the hydrogenation amount, and realizes the ratio of natural gas and hydrogen. The present invention realizes a stable gas mixing ratio of the two gases and high mixing accuracy. The equipment is skid-mounted as a whole, and an external stainless steel box with insulation and silencer functions is installed. The equipment is compact and beautiful, and is easy to install and move.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy utilization, and in particular to a hydrogen energy utilization gas blending system and a hydrogen and natural gas ratio control method. Background Art

[0002] Currently, the hydrogen energy utilization industry is poised for rapid growth and expansion. By building a hydrogen energy industry chain, we can promote the overall development of the new energy industry, establish demonstration projects for high-end new energy applications, and comprehensively upgrade the energy consumption structure. Natural gas blending with hydrogen is a primary form of hydrogen energy utilization. This process involves injecting hydrogen produced by electrolysis of renewable energy and excess hydrogen generated by hydrogen refueling stations operating at full capacity into the natural gas pipeline network to create hydrogen-blended natural gas. This hydrogen-blended natural gas is then transported to end users through the pipeline network, thus completing a "blending-transportation-utilization" hydrogen energy industry chain and promoting the deep integration of the power grid and gas network.

[0003] Natural gas hydrogen blending technology can not only improve the utilization rate of renewable energy, but also contribute to reducing pollutants generated by natural gas terminal combustion and solving the problem of air pollution.

[0004] The problems and defects of the prior art are:

[0005] (1) The existing natural gas hydrogen blending equipment has poor operating performance; and the dual-gas blending and flow-following gas mixing scheme is not adopted, resulting in unreliable technical performance, unstable process operation, and low safety control level.

[0006] (2) In the existing technical equipment, there is no front-end high-pressure hydrogen treatment, the materials of hydrogen pipeline components are not reasonably selected, the flow and component coordination and control are poor, the mixing uniformity effect is poor, and the signal feedback is slow, resulting in the mixing device being unable to fully meet practical applications.

[0007] The difficulty of solving the above problems and defects is as follows: (1) Hydrogen is transported by high-pressure long tube trailers. Hydrogen has special properties and is prone to hydrogen corrosion, hydrogen bulging, hydrogen embrittlement, etc. on carbon steel pipelines. Mature experience shows that there is no effect when the hydrogen content is below 3%. The test device requires a maximum hydrogen mixing ratio of 20%. The overall cost of the equipment is already limited, so careful consideration should be given to the selection of materials.

[0008] (3) Hydrogen is transported to the station building via a long-tube skid truck. The incoming gas pressure reaches 20 MPa, and the operating pressure is only 0.25-0.3 MPa, which has a very high pressure difference. Hydrogen is smaller in volume than other molecules in natural gas, and its leakage rate is generally 4-5 times faster than that of methane. The rate is even greater when the pressure is high. Therefore, it is very important to prevent the leakage of hydrogen molecules in the pipeline. It is critical to reasonably select hydrogen pipeline components such as high-pressure valves, filters, pressure regulators, pipes and fittings, and seals.

[0009] (4) The properties of hydrogen and methane are quite different, especially in terms of combustion performance. If the mixing uniformity of the two gases is low, or stratification occurs in the rear-end pipeline, the Wobbe number and combustion potential of the mixed gas will be disordered. Both gases are flammable and explosive media, which can easily affect the safety of hydrogen equipment. Therefore, the mixing uniformity of the core mixing component, the static mixer, must reach more than 98% to ensure uniform mixing. At the same time, the control principle must also ensure that the mixing ratio of the two wash bodies is accurate, the response is fast, and the safety interlock is reliable.

[0010] The significance of resolving the above issues and defects lies in the following: By utilizing the flow ratio signal for coarse adjustment and the component ratio signal for fine adjustment, rapid and stable dynamic mixing adjustment is truly achieved during equipment startup. The selection and structural configuration of the hydrogen pipeline filtration and pressure regulation equipment, as well as the choice of hydrogen front-end pipeline materials, ensure safe and stable hydrogen system supply. The internal structure of the static mixer, specifically designed for both hydrogen and natural gas, and the refinement of the control principle, truly achieves rapid and stable dynamic mixing system tracking and high mixing accuracy, ensuring the true applicability of the equipment. Summary of the Invention

[0011] To overcome the problems existing in the related art, the disclosed embodiments of the present invention provide a hydrogen energy utilization fuel gas blending system and a hydrogen and natural gas ratio control method.

[0012] The technical solution is as follows: According to a first aspect of the disclosed embodiment of the present invention, a method for controlling the ratio of hydrogen and natural gas in a hydrogen energy utilization gas blending system is provided, comprising:

[0013] The pneumatic emergency shut-off valves on the natural gas and hydrogen pipelines are interlocked with the hydrogen and natural gas inlet and outlet pressures, with the temperature transmitter, and with the automatic detection alarm for combustible gas leaks. When the value exceeds the set value by plus or minus 20%, the pneumatic emergency shut-off valves automatically close to cut off the hydrogen and natural gas sources;

[0014] The pressure transmitters at the outlets of natural gas and hydrogen pipelines monitor the adjusted pressures of natural gas and hydrogen in real time. When the values ​​exceed the set value by plus or minus 10%, the control system will sound an alarm.

[0015] The hydrogen section flow meter controls the degree of opening and closing of the hydrogen outlet regulating valve, compares the natural gas flow value, and controls the hydrogen flow according to the ratio requirement (the hydrogen blending amount in this system is set to any value between 3% and 20%, which can be set arbitrarily) to achieve the required gas mixing ratio value;

[0016] The detection equipment at the gas mixture outlet, in conjunction with the flow value after temperature and pressure compensation, jointly controls the opening of the regulating valves on the natural gas and hydrogen pipelines, controls the hydrogen volume flow, performs online adjustment and automatic following of the hydrogenation amount, and realizes the ratio of natural gas and hydrogen (conventional gas mixing equipment uses component content analyzer changes to complete automatic following dynamic adjustment. When the equipment is initially started, the value fluctuates greatly and it is difficult to achieve fast and stable adjustment. This system introduces two gas flow signals for preliminary coarse adjustment, and can quickly find the initial gas mixture balance point according to the flow ratio, so that the final fine adjustment according to the component can be achieved quickly and smoothly).

[0017] Furthermore, the detection equipment for the mixed gas outlet includes: a methane analyzer and a hydrogen analyzer.

[0018] According to a second aspect of the disclosed embodiments of the present invention, a control system for implementing the control method is provided, the control system comprising:

[0019] The PLC control cabinet is equipped with a touch screen for displaying the inlet and outlet pressures, outlet hydrogen content, valve status, and regulating valve opening; parameter settings; historical alarm query; and data report query.

[0020] Industrial computer, used for automatic control and safety cut-off protection of on-site gas mixing device.

[0021] Preferably, the PLC control cabinet automatically controls the entire gas mixing process based on the collected flow values ​​and gas concentrations; during the gas mixing process, the outlet pressure and outlet gas concentration are monitored in real time. When there are low and high reports of outlet gas concentration and low and high reports of outlet pressure, the required interlocking protection is set according to the downstream hydrogen requirements.

[0022] According to a third aspect of the disclosed embodiments of the present invention, a hydrogen energy utilization gas blending system is provided, the hydrogen energy utilization gas blending system comprising:

[0023] The hydrogen pipeline device, the source hydrogen enters the gas mixing pipeline through the inlet ball valve, the first pneumatic emergency shut-off valve, the filter, the hydrogen flow is measured by the flow meter, and the hydrogen dosage is adjusted by the regulating valve before entering the gas mixing device through the outlet ball valve;

[0024] Natural gas pipeline device, the source natural gas enters the gas mixing pipeline through the inlet ball valve, filter cut-off valve, pressure regulation and metering, and then passes through the regulating valve to the outlet ball valve to enter the gas mixing device;

[0025] The gas mixing device and the detection equipment at the gas mixing outlet are used to control the opening of the regulating valves on the natural gas and hydrogen pipelines together with the flow value after temperature and pressure compensation, control the volume flow of hydrogen, perform online adjustment and automatic following of the hydrogen addition amount, and realize the ratio of natural gas and hydrogen.

[0026] Preferably, the hydrogen pipeline device comprises:

[0027] The long tube trailer is loaded with hydrogen and transported to the station building's gas mixing skid-mounted equipment, where it enters the hydrogen pressure regulating pipeline through the connection of the hydrogen high-pressure hose, vent valve, manual high-pressure ball valve and pressure transmitter. The hydrogen pressure regulating pipeline includes a first-level hydrogen pressure regulating pipeline and a second-level hydrogen pressure regulating pipeline. The first-level hydrogen pressure regulating pipeline is set in two routes. An inlet ball valve, a first pneumatic emergency shut-off valve, a high-precision high-pressure filter, a first-level pressure regulator, a hydrogen pressure gauge, and a first-level outlet valve are set in each route to enter the gas confluence pipeline. The gas confluence is equipped with a pressure transmitter, a bypass manual ball valve, a safety relief valve, a hydrogen root valve and a hydrogen bypass valve group. Hydrogen enters the second-level pressure regulating pipeline through the manifold. The second-level hydrogen pressure regulating pipeline is set in two routes. An inlet ball valve, a second-level pressure regulator, a hydrogen pressure gauge, a hydrogen flow meter, a regulating valve, and a second-level outlet valve are set in each route to enter the gas confluence pipeline. The gas confluence is equipped with a pressure transmitter, a hydrogen thermometer, a temperature transmitter, a safety relief valve, a root valve and a bypass valve group. The two-stage safety valves are collected outside the skid.

[0028] Preferably, the gas is emptied and released after passing through the flame arrester, and a check valve is provided at the outlet to prevent hydrogen from flowing back; the material of the hydrogen pipeline device pipeline is 316L.

[0029] Preferably, the natural gas pipeline device comprises:

[0030] The inlet pipeline is equipped with a natural gas calorific value analyzer, pressure transmitter, temperature transmitter, natural gas pressure gauge, and natural gas thermometer. The natural gas then enters the pressure regulating and metering pipeline, which is divided into two routes. Each inlet is equipped with a manual ball valve, a high-precision filter, a second pneumatic emergency shut-off valve, a pressure regulator, a natural gas pressure gauge, a natural gas flow meter, a regulating valve, and an outlet manual ball valve to enter the gas conduit. The gas conduit is equipped with a pressure transmitter, a safety relief valve, a natural gas root valve, and a natural gas bypass valve group, which are then collected outside the skid.

[0031] Preferably, the gas is discharged after passing through a natural gas flame arrester.

[0032] Preferably, the gas mixing device comprises:

[0033] Natural gas and hydrogen enter the static mixer together for mixing. A guide pipe is set at the hydrogen inlet to mix the diffused hydrogen with the natural gas for the first time. The two gases are fully mixed through multiple sets of metal plate corrugated packing vortex generators in the static mixer. Instrument valves and differential pressure gauges are set on the static mixer body, and a drain valve is set at the lowest point below. The rear pipeline is equipped with methane and hydrogen component online analyzers, and at the rear are pressure transmitters, temperature transmitters, mixed gas pipeline pressure gauges, mixed gas thermometers, and outlet manual ball valves. A combustible gas leak alarm probe for real-time monitoring of gas leaks and an interlocked explosion-proof fan are installed in the box.

[0034] The technical solutions provided by the embodiments disclosed in the present invention may have the following beneficial effects:

[0035] The natural gas hydrogen blending test equipment developed by the present invention is used for fuel gas hydrogen blending tests. The natural gas utilizes pipeline gas, and the hydrogen gas source is a hydrogen long tube trailer. The inlet pressure is 20MPa, with two-stage pressure reduction, and the hydrogen blending ratio is 3%-20%. The equipment has been in operation for a long time and is used to test the use effect of hydrogen-blended natural gas. Through continuous improvement and innovation of the equipment, the expected goals have been achieved. The equipment has advanced technology and reliable operation.

[0036] Compared with the prior art, the advantages of the present invention further include:

[0037] The online blending technology with dynamically adjustable natural gas hydrogen blending ratio adopts an advanced and reliable dual-gas blending and follow-up flow mixing scheme. This technology has mature applications in the fields of LPG mixed with air to replace natural gas and coal gas mixed with high calorific value gas to increase calorific value. It has the characteristics of reliable technical performance, advanced technology, stable operation, and high level of safety control. This project adds innovations in the equipment design by adding front-end hydrogen high-pressure treatment, selection of 316L stainless steel material for hydrogen pipeline components, coordinated joint control of flow and components, improvement of gas mixture uniformity, and rapid signal feedback to ensure that the mixing device fully meets the use requirements of this innovative project.

[0038] In this dynamic flow-following gas mixing process, natural gas serves as the active gas source and hydrogen as the passive gas source. The passive gas source automatically and dynamically adjusts the opening of the regulating valve according to the flow and composition changes of the active gas source, thereby achieving a stable mixing ratio of the two gases and high mixing accuracy. The equipment is skid-mounted and has an external stainless steel box with insulation and silencer functions. The equipment is compact and beautiful, easy to install and move.

[0039] The results and advantages derived from experimental or test data compared with existing technologies are as follows: By utilizing flow ratio signals for coarse adjustment and component ratio signals for fine adjustment, rapid and stable dynamic mixing adjustment is truly achieved during equipment startup. The selection and structural configuration of the hydrogen pipeline filtration and pressure regulation equipment, as well as the choice of hydrogen front-end pipeline materials, ensure safe and stable hydrogen system supply. The internal structure of the static mixer, specifically designed for both hydrogen and natural gas, and the refinement of the control principle, truly achieves rapid and stable dynamic tracking and high mixing accuracy for the mixing system, ensuring the true applicability of the equipment.

[0040] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0042] Figure 1This is a schematic diagram of the hydrogen pipeline portion of the hydrogen energy utilization gas blending system provided by an embodiment of the present invention.

[0043] Figure 1 In: 1. Tube trailer; 2. Mixing skid-mounted equipment; 3. Hydrogen high-pressure hose; 4. Vent valve; 5. Manual high-pressure ball valve; 6. First pressure transmitter; 7. Inlet ball valve; 8. First pneumatic emergency shut-off valve; 9. First high-precision high-pressure filter; 10. First-stage pressure regulator; 11. Pressure gauge; 12. First-stage outlet valve; 13. Second-stage pressure transmitter; 14. Bypass manual ball valve; 15. One valve; 16. First safety relief valve; 17. First-stage bypass valve group; 18. Second-stage inlet ball valve; 19. Second-stage pressure regulator; 20. Second hydrogen pressure gauge; 21. Flow meter; 22. Control valve; 23. Second-stage outlet valve; 24. Third-stage pressure transmitter; 25. Hydrogen thermometer; 26. Temperature transmitter; 27. Second-stage bypass valve group; 28. Two valves; 29. ​​Second safety relief valve; 30. Check valve.

[0044] Figure 2 This is a partial schematic diagram of a natural gas pipeline provided by an embodiment of the present invention.

[0045] Figure 2 Chinese: 31. Natural gas calorific value analyzer; 32. Fourth pressure transmitter; 33. Temperature transmitter; 34. Second pressure gauge; 35. Natural gas thermometer; 36. Manual ball valve; 37. Second high-precision filter; 38. Second pneumatic emergency shut-off valve; 39. Pressure regulator; 40. Second natural gas pressure gauge; 41. Flow meter; 42. Control valve; 43. Outlet manual ball valve; 44. Fifth pressure transmitter; 45. Natural gas bypass valve group; 46. Natural gas root valve; 47. Third safety relief valve.

[0046] Figure 3 It is a partial schematic diagram of the mixed gas pipeline provided by an embodiment of the present invention.

[0047] Figure 3 Chinese: 49. Static mixer; 50. Instrument valve; 51. Differential pressure gauge; 52. Draft tube; 53. Multiple sets of metal plate corrugated packing vortex generators; 54. Methane; 55. Hydrogen component online analyzer; 56. Sixth pressure transmitter; 57. Second temperature transmitter; 58. Mixed gas pipeline pressure gauge; 59. Mixed gas thermometer; 60. Outlet manual ball valve; 62. Drain valve; 63. Combustible gas leak alarm probe; 64. Explosion-proof fan.

[0048] Figure 4 Schematic diagram of a hydrogen flame arrester provided in an embodiment of the present invention.

[0049] Figure 4 Chinese: 61. Hydrogen flame arrester.

[0050] Figure 5 Schematic diagram of a natural gas flame arrester provided by an embodiment of the present invention.

[0051] Figure 5 Chinese: 48. Natural gas flame arrester.

[0052] Figure 6 This is a schematic diagram of the general assembly of the hydrogen pipeline provided by an embodiment of the present invention.

[0053] Figure 7 This is a schematic diagram of the general assembly of a natural gas pipeline provided by an embodiment of the present invention.

[0054] Figure 8 This is a schematic diagram of the general assembly of the mixed gas pipeline provided by an embodiment of the present invention.

[0055] Figure 6 、 7 8: N1 NG inlet; N2 mixed gas outlet; N3 vent outlet 1; N4 vent outlet 2; N5 hydrogen inlet; N6 reserved port; N7 instrument air outlet; N8 sewage outlet (natural gas). The mixed gas outlet's external flange is made of 20# material to facilitate subsequent pipe connection.

[0056] Figure 9 This is a rendering of a natural gas pipeline provided by an embodiment of the present invention.

[0057] Figure 10 This is a rendering of a hydrogen pipeline provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0058] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0059] The disclosed embodiment of the present invention provides a method for controlling the ratio of hydrogen and natural gas in a hydrogen energy utilization gas blending system, comprising:

[0060] (1) The pneumatic emergency shut-off valves on the hydrogen and natural gas pipelines are interlocked with the inlet and outlet pressure and temperature transmitters and the automatic detection alarm for combustible gas leakage on both sides. When the value exceeds the limit, the shut-off valve automatically closes and cuts off the gas source, and the system stops working to prevent the leakage and accumulation of excessive hydrogen and gas.

[0061] (2) The outlet pressure transmitters of natural gas and hydrogen pipelines monitor the pressure of natural gas and hydrogen at any time to ensure that the pressure reaches the required range. If the value exceeds a certain range, the control system will alarm and prompt the operator to adjust the working pressure of the pressure regulator and the regulating valve.

[0062] (3) The hydrogen section flow meter controls the degree of opening and closing of the hydrogen outlet regulating valve, compares the natural gas flow value, and controls the hydrogen flow according to the ratio requirements to achieve the initial mixed gas ratio requirements.

[0063] (4) The methane analyzer and hydrogen analyzer at the mixed gas outlet, together with the flow value after temperature and pressure compensation, jointly control the opening of the regulating valve on the natural gas and hydrogen pipelines, accurately and quickly control the hydrogen volume flow, realize online adjustment and automatic following of the hydrogen addition amount, and achieve accurate ratio of natural gas and hydrogen.

[0064] The present invention provides a control system for implementing the control method, the control system comprising:

[0065] The PLC control cabinet is equipped with a touch screen for displaying the inlet and outlet pressures, outlet hydrogen content, valve status, and regulating valve opening; parameter settings; historical alarm query; and data report query.

[0066] Industrial computer, used for automatic control and safety cut-off protection of on-site gas mixing device.

[0067] Preferably, the PLC control cabinet automatically controls the entire gas mixing process based on the collected flow values ​​and gas concentrations; during the gas mixing process, the outlet pressure and outlet gas concentration are monitored in real time. When there are low and high reports of outlet gas concentration and low and high reports of outlet pressure, the required interlocking protection is set according to the downstream hydrogen requirements.

[0068] like Figure 1-Figure 5 As shown, a hydrogen energy utilization gas mixing system provided by the disclosed embodiment of the present invention includes:

[0069] (1) Hydrogen pipeline

[0070] The long tube trailer 1 (maximum pressure 20MPa) is loaded with hydrogen and transported to the station building's gas mixing skid-mounted equipment 2, and enters the hydrogen pressure regulating pipeline through the connection of the hydrogen high-pressure hose, the vent valve 4 (pressure relief before removing the hose), the manual high-pressure ball valve 5 (on-off valve) and the first pressure transmitter 6 (online pressure detection, remote signal transmission interlock). The hydrogen pressure regulating pipeline includes a first-level hydrogen pressure regulating pipeline and a second-level hydrogen pressure regulating pipeline. The first-level hydrogen pressure regulating pipeline is provided with two routes (one open and one standby). Each route is provided with an inlet ball valve 7 (manual opening and closing switch), a first pneumatic emergency shut-off valve 8 (the valve is a "fault closed" type, which is controlled by the interlocking control of the device system PLC control cabinet), a first high-precision high-pressure filter 9 (to filter out dust, fine particles and other impurities), a first-level pressure regulator 10 (to stabilize the follow-up gas source pressure), a hydrogen pressure gauge 11 (to display the adjusted pressure), and an outlet valve 12 (manual opening and closing switch) to enter the gas manifold. The gas manifold is provided with a second pressure transmitter 13 (online pressure detection, remote signal transmission interlock), a bypass manual ball valve 14 (which can be connected to the medium-pressure gas source of the hydrogen pipeline network), a first safety relief valve 16, a valve 15 and a bypass valve group 17 (safety discharge and automatic relief). Hydrogen enters the second-level pressure regulating pipeline through the manifold. The second-level hydrogen pressure regulation The pipeline is set up in two routes (one open and one backup), and each route is equipped with a second inlet ball valve 18 (manual opening and closing switch), a two-stage pressure regulator 19 (stabilizes the follow-up gas source pressure, slightly higher than the active gas source pressure), a second hydrogen pressure gauge 20 (displays the adjusted pressure), a hydrogen flowmeter 21 (monitors the hydrogen follow-up volume flow), a regulating valve 22 (dynamically adjusts the hydrogen follow-up flow according to the monitoring signal), and a second regulating outlet valve 23 (manual opening and closing switch) entering the gas conduit. The gas conduit is equipped with a third pressure transmitter 24 (online pressure detection, signal remote transmission interlock), a hydrogen thermometer 25 (displays hydrogen temperature), a temperature transmitter 26 (online temperature detection, signal remote transmission interlock), a second safety relief valve 29, two root valves 28 and a second bypass valve group 27 (safety emptying and automatic release). The two-stage safety valves are collected outside the skid and emptied and released after passing through the flame arrester 61. A check valve 30 is set at the outlet to prevent natural gas backflow, etc. The pipeline is made of 316L material and all components are made of hydrogen-specific materials.

[0071] (2) Natural gas pipelines

[0072] Natural gas enters the natural gas pipeline through the gas supply pipeline. The inlet pipeline is equipped with a natural gas calorific value analyzer 31 (to detect the calorific value of the incoming natural gas), a fourth pressure transmitter 32 (online pressure detection, signal remote transmission interlock), a temperature transmitter 33 (online temperature detection, signal remote transmission interlock), a second pressure gauge 34 (on-site pressure display), and a natural gas thermometer 35 (on-site temperature display). The natural gas then enters the pressure regulating and metering pipeline, which is divided into two routes (one open and one backup). Each inlet is equipped with a manual ball valve 36 (manual opening and closing switch), a second high-precision filter 37 (to filter out moisture and fine coal dust, dust and other impurities), and a second pneumatic emergency shut-off valve 38 (this valve is "failure closed" The gas enters the gas conduit through a PLC control cabinet interlocking control system (e.g., a pressure regulator 39 (stabilizing the active gas source pressure), a second natural gas pressure gauge 40 (displaying the regulated pressure), a natural gas flowmeter 41 (measuring the instantaneous volumetric flow of natural gas), a regulating valve 42 (automatically regulating the natural gas flow), and an outlet manual ball valve 43 (manually switching on and off). The conduit is equipped with a fifth pressure transmitter 44 (for online pressure detection and remote signal transmission interlocking), a third safety relief valve 47, a natural gas root valve 46, and a natural gas bypass valve assembly 45 (for safe venting and automatic venting). The gas is then conveyed to the outside of the skid and vented through a natural gas flame arrester 48. To reduce equipment costs, the pipeline components are made of carbon steel, and the pipes are conventional carbon steel pipes.

[0073] (3) Mixed gas pipeline

[0074] Natural gas and hydrogen enter the static mixer 49 for mixing. A guide pipe 52 is set at the hydrogen inlet to mix the diffused hydrogen with the natural gas for the first time. The two gases are fully mixed through multiple sets of metal plate corrugated packing vortex generators 53 in the static mixer (the mixing uniformity of the two gases can reach more than 98% after being fully mixed). The static mixer body is equipped with an instrument valve 50 and a differential pressure gauge 51 (to monitor the packing blockage in real time), a drain valve 62 is set at the lower point, and a methane 54 and hydrogen component online analyzer 55 is installed in the rear pipeline to analyze the methane content in the mixed gas. The gas mixture is equipped with a pressure transmitter 56 (online pressure detection, remote signal transmission and interlocking), a second temperature transmitter 57 (online temperature detection, remote signal transmission and interlocking), a mixed gas pipeline pressure gauge 58 (displaying the mixed gas pressure), a mixed gas thermometer 59 (displaying the mixed gas temperature), an outlet manual ball valve 60 (manual start-stop system), and a combustible gas leak alarm probe 63 (real-time monitoring of gas leaks, remote signal transmission) and an interlocked explosion-proof fan 64.

[0075] Figure 6 This is a schematic diagram of the general assembly of the hydrogen pipeline provided by an embodiment of the present invention.

[0076] In the present invention, Figure 7This is a schematic diagram of the general assembly of a natural gas pipeline provided by an embodiment of the present invention.

[0077] Figure 8 This is a schematic diagram of the general assembly of the mixed gas pipeline provided by an embodiment of the present invention.

[0078] Figure 6 、 7 , 8: N1 NG inlet; N2 mixed gas outlet; N3 release outlet 1; N4 release outlet 2; N5 hydrogen inlet; N6 reserved port; N7 instrument air outlet; N8 sewage outlet (natural gas). Among them, the flange material of the mixed gas outlet external interface is 20#, which is convenient for the subsequent connection of the other party's pipeline.

[0079] The present invention is further described below in conjunction with specific device hardware and parameters.

[0080] Example

[0081] (1) Technical parameters of gas mixing equipment

[0082] 1. Overview of device name

[0083] Gas and hydrogen mixing equipment

[0084] 2. Environmental and climatic conditions

[0085] The lowest annual temperature is -25℃;

[0086] Extreme maximum temperature: 36.8℃;

[0087] Average annual precipitation: 750 mm.

[0088] 3. Temperament components

[0089] 3.1 Coalbed Methane Quality

[0090] Since the methane concentration of coalbed methane is unstable, the methane concentration is between 90% and 99%, and the rest is mainly nitrogen, oxygen, carbon dioxide, etc., and the gas contains moisture and fine coal dust, dust and other impurities, the equipment provided by the seller must meet the gas quality requirements.

[0091] 3.2 Hydrogen gas quality

[0092] Hydrogen concentration is 80%-99%

[0093] 3.3 Hydrogen doping ratio

[0094] The hydrogen blending ratio is 3%-20%.

[0095] 3.4 Traffic

[0096] The blending equipment has a designed hourly flow rate of 600 cubic meters per hour, with hydrogen flow rates ranging from 3 to 30 cubic meters per hour in the early stages and 20 to 120 cubic meters per hour in the later stages. The natural gas flow rate is 20 to 120 Nm³ / h in the early stages and 100 to 600 Nm³ / h in the later stages. The equipment has a 25% expansion capacity reserve; after replacing the flowmeter, the blending equipment can increase its designed hourly flow rate by 25%.

[0097] 3.5 Pressure

[0098] Natural gas (coalbed methane) inlet pressure of mixing equipment: 0.3-0.4Mpa.

[0099] The inlet pressure of hydrogen for blending equipment is 20MPa (long tube trailer). In the future, if on-site hydrogen production is considered, the inlet pressure will be 0.5-0.8MPa.

[0100] The outlet pressure of the blending equipment is 0.25-0.3MPa, and the natural gas and hydrogen are mixed evenly.

[0101] 3.6 Control System

[0102] This system features a PLC control cabinet and an industrial computer, enabling automatic control of the on-site gas mixing device and safety shutoff protection. A touch screen, also accessible from the industrial computer, displays the equipment's inlet and outlet pressures, outlet hydrogen content, valve status, and regulating valve opening; provides parameter settings, historical alarm queries, and data report inquiries.

[0103] Based on the user's outlet hydrogen concentration requirements, this equipment requires that the corresponding parameters be modified on the touch screen or industrial computer to ensure that the mixing equipment outlet parameters meet the requirements. The PLC automatically controls the entire mixing process based on the collected flow rate and gas concentration. During the mixing process, the outlet pressure and outlet gas concentration are monitored in real time. When the outlet gas concentration is under- or over-reported, or the outlet pressure is under- or over-reported, the required interlocking protection function is set according to the characteristics of the downstream hydrogen (disconnecting the hydrogen circuit to ensure that the equipment outlet gas meets the requirements). The mixing device controls the entire mixing system through a PLC control cabinet and industrial computer. The control cabinet can be non-explosion-proof and installed in the control room.

[0104] (2) System process description:

[0105] (1) Natural gas section

[0106] Natural gas enters the natural gas pipeline through the gas supply line. The line is equipped with inlet and outlet ball valves, a filter, a second pneumatic emergency shut-off valve (this valve should be a "fail-close" type and controlled by the device system PLC control cabinet), a pressure regulator, a flow meter, a regulating valve, a transmitter, a safety relief valve, and testing instruments. The pipeline is dual-circuited, one for use and one for backup.

[0107] The source natural gas enters the gas mixing pipeline through the inlet ball valve, filter cut-off valve, and after pressure regulation and metering, it passes through the regulating valve to the outlet ball valve and enters the gas mixing device.

[0108] The safety valve has a release function. When the pressure in the pipeline exceeds the set pressure of the safety valve, the safety valve will trip and discharge the gas in the pipeline to the relief pipeline to ensure the safety of equipment and personnel.

[0109] (2) Hydrogen section

[0110] Hydrogen loaded from tank trucks enters the hydrogen pipeline through the hydrogen unloading column. The line is equipped with an inlet ball valve, a first pneumatic emergency shut-off valve (this valve should be a "fail-close" type and controlled by the system's PLC control cabinet), a filter, a pressure regulator, a flow meter, a transmitter, a regulating valve, an outlet ball valve, and a safety relief valve. The pipeline is dual-route, one for active use and one for backup. A second-phase hydrogen pipeline interface is reserved after the pressure regulator.

[0111] The source hydrogen enters the mixing pipeline through the inlet ball valve, shut-off valve, and filter, and the hydrogen flow is measured by a flow meter. After the hydrogen dosage is adjusted by a regulating valve, it enters the mixing device through the outlet ball valve.

[0112] The safety valve has a release function. When the pressure in the pipeline exceeds the set pressure of the safety valve, the safety valve will trip and discharge the gas in the pipeline to the relief pipeline to ensure the safety of equipment and personnel.

[0113] A check valve is installed at the hydrogen outlet to prevent backflow.

[0114] (3) Internal control (gas mixing principle)

[0115] The pneumatic emergency shut-off valves on the hydrogen and natural gas pipelines are interlocked with the inlet pressure transmitters of both sides. When the pressure exceeds the set pressure, the pneumatic emergency shut-off valves close to cut off the gas source and stop working.

[0116] The natural gas pipeline outlet pressure transmitter controls the opening and closing degree of the natural gas outlet regulating valve to adjust the natural gas pressure before mixing to the required range.

[0117] The hydrogen section flowmeter controls the opening and closing degree of the hydrogen outlet regulating valve, and controls the hydrogen flow according to the ratio requirements to achieve the initial mixed gas ratio requirements.

[0118] The methane analyzer and hydrogen analyzer at the mixed gas outlet jointly control the opening of the regulating valve on the hydrogen pipeline to control the hydrogen flow rate and achieve an accurate ratio of natural gas and hydrogen.

[0119] The present invention relates to the following hardware instruments:

[0120] (a) Detection instruments: A methane concentration analyzer is installed at the natural gas inlet, and a methane concentration analyzer and a hydrogen concentration analyzer are installed at the outlet of the mixing device. The seller uses the brand of Japan Riken for the methane concentration analyzer and the brand of Hunan Tuoan for the hydrogen concentration analyzer. The instruments have fast detection speed and sensitive response, and the detection concentration data is transmitted to the station control system through the data interface of the PLC control cabinet.

[0121] (b) Flow meter: The gas flow meter is a Roots flow meter, and the hydrogen flow meter is a high-precision flow meter suitable for hydrogen measurement, which is a swirl flow meter. The data obtained by the flow meter must be transmitted to the station control system through the PLC control cabinet data interface.

[0122] (c) Materials for hydrogen: All valves, filters, pressure regulators, flow meters, regulating valves, shut-off valves, check valves, etc. used for hydrogen are selected from materials suitable for the quality of hydrogen, and the processing technology and seals are also selected.

[0123] (d) Material selection for hydrogen pipe fittings: Because hydrogen has special properties that can cause hydrogen corrosion, hydrogen bulging, and hydrogen embrittlement to pipelines, 316L or 316SS materials are selected for the pipelines. The pipelines are degreased and polished with alkaline liquid.

[0124] (e) Skid-mounted part

[0125] (1) The gas mixing device consists of a skid-mounted device.

[0126] (2) Vertical adjustment bolts for on-site installation of skid rigs. Electroplating of railings, pedals, bolts and nuts.

[0127] (3) The center distance between all anchor bolt holes shall maintain a tolerance of 1.6mm, without accumulation. The position of other connecting parts shall maintain a tolerance of 6.4mm.

[0128] (4) The skid has sufficient rigidity in all directions to ensure that it remains aligned without deviation during long-term operation. All loaded components are fully penetrated welded.

[0129] (5) The skid top panel has a liquid collection edge and a sewage discharge port. The skid top panel is not used as a mounting surface for rotating equipment or pipes / equipment.

[0130] (6) All structural components (except lifting rings and shackles) have a safety factor of at least 2.0.

[0131] (7) The supplier shall reasonably set the size of the skid according to the transportation conditions and the convenience of on-site maintenance.

[0132] (8) The selection of materials ensures that the performance of the mixing device meets the requirements of the working conditions and can ensure its service life.

[0133] (9)Major components and standard parts shall be provided with material chemical composition and mechanical properties test reports, as well as non-destructive testing reports.

[0134] (f) Instruments

[0135] (1) All instruments are explosion-proof type, explosion-proof grade: ExdIIBT4, protection grade: IP65.

[0136] (2) Transmitter 4-20mA DC signal output, 24V DC power supply.

[0137] (3) The solenoid valve is powered by 24VDC and the explosion-proof grade is not lower than ExdIIBT4.

[0138] (4) The control valve is equipped with an intelligent positioner. The accessories of the pneumatic valve are provided by the seller. The pressure pipe is made of ￠8 stainless steel. The pneumatic valve is equipped with an air source triplex.

[0139] (5) The local temperature indicator uses a universal bimetallic thermometer with a stainless steel outer protective sleeve. The dial diameter is 100mm and the connection method is threaded connection M27×2.

[0140] (6) For remote temperature measurement, an integrated temperature transmitter with a stainless steel protective sleeve is used. The connection method is threaded connection.

[0141] (7) The pressure gauge uses stainless steel spring tube, the pressure gauge shell material is stainless steel, the dial diameter is 100mm, and the process interface is M20*1.5.

[0142] (8) The on-site junction box is made of cast aluminum, explosion-proof grade: ExeIIBT4, protection grade: IP65.

[0143] (9) Wiring method: The instrument is connected to the on-site junction box through a cable steel pipe.

[0144] (10) The pneumatic signal pipelines and valve components connected to the actuator are made of stainless steel and use a ferrule connection method.

[0145] The following is a further description of the device development process of the present invention.

[0146] (1) Natural gas + hydrogen mixing skid, which is a mixing skid that mixes natural gas and hydrogen. During the operation of the equipment, the present invention fully absorbs foreign pressure regulation technology and combines it with domestic actual conditions to research and develop equipment with independent intellectual property rights. It has the characteristics of complete functions, stable performance, high pressure regulation accuracy, and compact structure.

[0147] The present invention has two natural gas pipelines, one for use and one for backup. The pipelines are equipped with ball valves, filters, roots flowmeters, and regulating valves. The natural gas is filtered and flow metered by the filter. The regulating valve can adjust the flow of natural gas to meet the mixing ratio. The natural gas flow rate Q max = 600Nm3 / h. The effect diagram is as follows Figure 9 .

[0148] There are two hydrogen lines, one for use and one for backup. The lines are equipped with a ball valve, a first pneumatic emergency shut-off valve, a filter, a flow meter, a pressure regulator, a regulating valve, and a check valve. The hydrogen is filtered, metered, and pressure-regulated to the required pressure. The regulating valve adjusts the hydrogen flow rate to meet the desired mixing ratio. The check valve prevents the mixed gas from entering the line. The hydrogen flow rate Qmax = 120 Nm³ / h. The effect diagram is as follows: Figure 10 .

[0149] Design equipment technical parameters:

[0150] Natural gas inlet pressure: 0.3-0.4MPa.

[0151] Hydrogen inlet pressure range: 0.5-20MPa.

[0152] Mixed gas outlet pressure range: 0.25-0.3MPa.

[0153] Natural gas inlet flange: HG20592 DN80—1.6MPa RF.

[0154] Hydrogen inlet: DN25 welding end: ￠34*6.

[0155] Mixed gas outlet flange: HG20592 DN80—1.6MPa RF.

[0156] Installation Instructions:

[0157] After the equipment arrives at the site, it should be placed on the foundation and fixed with anchor bolts. The equipment should be well connected to the ground grid. The inlet and outlet flanges of the mixing device should be connected to the flange of the user's pipe network. It can only be used after passing the airtight test.

[0158] operate:

[0159] a. First, observe the position of each valve in the skid. The root valve of the pressure gauge is normally open, and the other valves remain closed.

[0160] b. First adjust the valve of the natural gas pipeline, observe the pressure at the inlet end, and after confirming that there is incoming gas pressure, slowly open the inlet valve, and then open the metering valve (the mixed gas outlet valve is closed).

[0161] c. Then, open the valve of the hydrogen pipeline in the same way and adjust the first and second pressure regulators to bring the hydrogen pressure to the operating pressure. During the pressure adjustment and operation process, always pay attention to the inlet and outlet pressure values ​​of the air pipeline.

[0162] d. The present invention can first pass natural gas to the downstream official website for users to use, and then open the hydrogen outlet valve for mixing, and adjust various parameters to make the outlet hydrogen content meet the requirements.

[0163] e. When out of service, first close the valves at the inlet ends of each pipeline, wait until the remaining gas in the skid is used up, and then close the outlet valve of the gas mixing skid. If it is out of service for a long period of time, discharge the remaining gas in the gas mixing skid through the drain valve.

[0164] control system

[0165] The present invention is equipped with a PLC control cabinet with a touch screen on the control panel and an industrial computer in the control room. The touch screen and the industrial computer can simultaneously display the values ​​of the remote instruments and valve status in the mixing skid and perform related operations.

[0166] The main components include:

[0167] voltage regulator

[0168] a. Natural gas: Technical parameters: 299H DN50; Inlet pressure: 0.3-0.4MPa Outlet pressure: 0.3MPa.

[0169] Hydrogen Road: Technical Parameters: 44-2200;

[0170] DN25 inlet pressure: 20MPa;

[0171] Outlet pressure: 0.5MPa.

[0172] Hydrogen Road: Technical parameters: 44-3200DN25;

[0173] Inlet pressure: 0.5MPa;

[0174] Outlet pressure: 0.3MPa.

[0175] b. Steps to adjust pressure:

[0176] *Pressure regulator: Please read the pressure regulator's instruction manual carefully before adjusting the pressure. Operate according to the instruction manual.

[0177] c. Maintenance of voltage regulator:

[0178] Check the working pressure of the pressure regulator every day to see if it is normal. The output pressure of the pressure regulator is normal if it changes within ±5%. When the output pressure of the pressure regulator exceeds the normal gas supply pressure due to changes in gas flow, the outlet pressure of the pressure regulator should be adjusted in time.

[0179] Roots flowmeter:

[0180] Technical parameters: DN80 PN16 Flow rate: 1000Nm3 / H Working pressure: 0.05MPa Quantity: 2.

[0181] Technical parameters: DN100 PN16 Flow rate: 3000Nm3 / H Working pressure: 0.65-0.8MPa Quantity: 2.

[0182] Precession vortex flowmeter:

[0183] Small road: Technical parameters: DN15 PN16 Flow rate: 0.5-9m3 / h Working pressure: 0.3MPa Quantity: 1

[0184] Road: Technical parameters: DN25 PN16 Flow rate: 3-30m 3 / h Working pressure: 0.3MPa Quantity: 1.

[0185] valve:

[0186] a. If the valve shaft is too tight when opened, add a little oil for lubrication.

[0187] b. When air leakage occurs at the valve opening shaft, use a wrench to tighten the screws on the flange cover. The screws should be tightened symmetrically, and not too heavily on one side and too light on the other.

[0188] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the appended claims.

[0189] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure should be limited by the appended claims.

Claims

1. A method for controlling the ratio of hydrogen and natural gas in a hydrogen energy utilization gas blending system, characterized in that: The hydrogen energy utilization gas blending system includes: The hydrogen pipeline device, the source hydrogen enters the gas mixing pipeline through the inlet ball valve, the first pneumatic emergency shut-off valve, the first high-precision high-pressure filter, the hydrogen flow is measured by the flow meter, and the hydrogen dosage is adjusted by the regulating valve before entering the gas mixing device through the outlet valve; Natural gas pipeline device, the source natural gas enters the gas mixing pipeline through the manual ball valve, the second high-precision filter, the second pneumatic emergency shut-off valve, and after pressure regulation and metering, passes through the regulating valve to the outlet manual ball valve and enters the gas mixing device; The gas mixing device and the detection equipment at the gas mixing outlet work together with the flow value after temperature and pressure compensation to control the opening of the regulating valves on the natural gas and hydrogen pipelines, control the hydrogen volume flow, and perform online adjustment and automatic tracking of the hydrogen addition amount to achieve the natural gas and hydrogen ratio; The hydrogen pipeline device comprises: The long tube trailer is loaded with hydrogen and transported to the station building's gas mixing skid-mounted equipment. The hydrogen enters the hydrogen pressure regulating pipeline by connecting the hydrogen high-pressure hose, vent valve, manual high-pressure ball valve and the first pressure transmitter. The hydrogen pressure regulating pipeline includes a first-level hydrogen pressure regulating pipeline and a second-level hydrogen pressure regulating pipeline. The first-level hydrogen pressure regulating pipeline is equipped with two routes. Each route is equipped with an inlet ball valve, a first pneumatic emergency shut-off valve, a first high-precision high-pressure filter, a first-level pressure regulator, a hydrogen pressure gauge, and a first-level outlet valve to enter the gas converging pipeline. The gas converging pipeline is equipped with a second pressure transmitter. The hydrogen enters the secondary hydrogen pressure regulating pipeline through the gas converging pipeline. The secondary hydrogen pressure regulating pipeline is provided with two routes. Each route is provided with a second inlet ball valve, a secondary pressure regulator, a second hydrogen pressure gauge, a hydrogen flow meter, a regulating valve, and a secondary regulating outlet valve to enter the gas converging pipeline. The gas converging pipeline is provided with a third pressure transmitter, a hydrogen thermometer, a temperature transmitter, a second safety relief valve, two valves and a second bypass valve group. The two-stage safety relief valves are combined to the outside of the skid; The method for controlling the ratio of hydrogen and natural gas in the hydrogen energy utilization gas blending system includes: The pneumatic emergency shut-off valves on the natural gas and hydrogen pipelines are interlocked with the hydrogen and natural gas inlet and outlet pressures, with the temperature transmitter, and with the automatic detection alarm for combustible gas leaks. When the pressure value exceeds the set value by plus or minus 20%, the pneumatic emergency shut-off valves automatically close to cut off the hydrogen and natural gas sources; The pressure transmitters at the outlets of natural gas and hydrogen pipelines monitor the adjusted pressures of natural gas and hydrogen in real time. When the values ​​exceed the set value by plus or minus 10%, the control system will sound an alarm. The hydrogen section flowmeter controls the opening and closing degree of the hydrogen outlet regulating valve, compares it with the natural gas flow value, and controls the hydrogen flow according to the ratio requirements to ensure that the hydrogen mixing ratio meets the set value; The detection equipment at the mixed gas outlet, together with the flow value after temperature and pressure compensation, controls the opening of the regulating valves on the natural gas and hydrogen pipelines, controls the hydrogen volume flow, performs online adjustment and automatic following of the hydrogen addition amount, and realizes the natural gas and hydrogen ratio.

2. The method for controlling the ratio of hydrogen and natural gas in a hydrogen energy utilization fuel gas blending system according to claim 1, characterized in that: The hydrogen mixing ratio is set as follows: the hydrogen mixing amount is 3% to 20%; The detection equipment for the mixed gas outlet includes: methane analyzer and hydrogen analyzer.

3. The method for controlling the ratio of hydrogen and natural gas in a hydrogen energy utilization fuel gas blending system according to claim 1, characterized in that: Natural gas pipeline installations include: The inlet pipeline is equipped with a natural gas calorific value analyzer, pressure transmitter, temperature transmitter, natural gas pressure gauge, and natural gas thermometer. The natural gas then enters the pressure regulating and metering pipeline, which is divided into two routes. Each inlet is equipped with a manual ball valve, a second high-precision filter, a second pneumatic emergency shut-off valve, a pressure regulator, a natural gas pressure gauge, a natural gas flow meter, a regulating valve, and an outlet manual ball valve to enter the gas converging pipeline. The gas converging pipeline is equipped with a pressure transmitter, a safety relief valve, a natural gas root valve, and a natural gas bypass valve group, which are then collected outside the skid.

Images