Complementary energy utilization system of natural gas pressure regulating station

Abstract

The invention provides a complementary energy utilization system for a natural gas pressure regulating station, and aims to reduce external energy consumption by recycling complementary energy, so that the working efficiency and the economic performance of the pressure regulating station are improved, and the purposes of energy conservation and emission reduction are achieved. The complementary energy utilization system comprises a complementary energy recovery device which is installed at a natural gas pressure regulating outlet, captures pressure energy released in the pressure regulating process and converts the pressure energy into electric energy; the heater is used for heating the natural gas in an electric heating or heat exchange manner, and compensating the temperature drop caused by the pressure drop in the pressure regulation and transmission process; the energy storage system is configured to store the electric energy generated by the complementary energy recovery device; and the intelligent control system is used for dynamically adjusting the output power of the complementary energy recovery device based on the pressure and temperature of the natural gas and the operation state of the complementary energy recovery device, controlling the compensation heating of the heater and carrying out multi-stage distribution on the electric energy.

Description

Technical Field

[0001] The present invention relates to a system for utilizing the surplus energy of a natural gas pressure regulating station. Background Art

[0002] In current natural gas pressure regulating station operations, the pressure drop caused by the pressure regulating process often leads to a significant decrease in the gas temperature. This temperature drop not only affects the transportation efficiency of the natural gas after pressure regulation but also poses challenges to the operational stability of downstream equipment. Traditionally, to compensate for the heat energy loss caused by pressure regulation, electric heating devices or heat exchangers are usually used to preheat the natural gas. However, although this method can solve the problem to a certain extent, it faces disadvantages such as high energy consumption, complex equipment structure, and high maintenance costs.

[0003] The main technical challenge lies in how to efficiently utilize the surplus energy released during the pressure regulating process and convert it into a usable energy form, thereby reducing the dependence on external energy sources, improving the overall energy efficiency and economic benefits of the system. Currently, there is serious energy waste in this link in many natural gas pressure regulating stations: on the one hand, in order to compensate for the sudden temperature drop caused by the pressure reduction, it is necessary to use electric heating equipment with high energy consumption; on the other hand, a large amount of surplus energy released during the pressure regulating process fails to be effectively recovered and reused and cannot be converted into other useful energy forms. Summary of the Invention

[0004] The present invention proposes a system for utilizing the surplus energy of a natural gas pressure regulating station, aiming to reduce external energy consumption through the reuse of surplus energy, thereby improving the working efficiency and economic performance of the pressure regulating station and achieving the goal of energy conservation and emission reduction.

[0005] According to one aspect of the embodiment, a system for utilizing the surplus energy of a natural gas pressure regulating station is proposed, including: a surplus energy recovery device installed at the natural gas pressure regulating outlet, which captures the pressure energy released during the pressure regulating process and converts it into electric energy; a heater that heats the natural gas by electric heating or heat exchange to compensate for the temperature drop caused by the pressure reduction during the pressure regulation and transmission; a energy storage system configured to store the electric energy generated by the surplus energy recovery device; and an intelligent control system that dynamically adjusts the output power of the surplus energy recovery device, controls the compensating heating of the heater, and performs multi-level distribution of the electric energy based on the pressure, temperature of the natural gas, and the operating state of the surplus energy recovery device.

[0006] In some examples, the surplus energy recovery device includes: an expander that converts the pressure energy of high-pressure natural gas into mechanical energy through an expansion process; and a generator that converts the mechanical energy into electric energy.

[0007] In some examples, the expander reduces the natural gas pressure from 10 MPa to 3 MPa.

[0008] In some examples, the energy storage system includes: a battery for short-term energy storage and a liquid air energy storage module for long-term energy storage.

[0009] In some examples, the energy storage system is configured to supply power to the pressure regulating station through the battery or liquid air energy storage module when there is a power shortage, ensuring that the natural gas temperature does not fall below a safety threshold and the pressure is stable.

[0010] In some examples, the intelligent control system includes: a pressure sensor and a temperature sensor for real-time monitoring of natural gas pressure and temperature; an operation status monitoring module, including a speed sensor and a current monitoring unit, for monitoring the speed of the expander and the power generation of the generator; a PLC controller for dynamically adjusting the output power of the surplus energy recovery device based on the monitoring data of the pressure sensor, temperature sensor and operation status monitoring module, and optimizing the power distribution strategy.

[0011] In some examples, the PLC controller executes the following control logic: when the natural gas temperature is lower than 5°C, the electric energy is preferentially allocated to the heater for temperature rise compensation; when the temperature approaches 10°C, the heater power is gradually reduced until it is shut down; during the low demand period, the excess electric energy is preferentially stored in the battery or liquid air energy storage module.

[0012] In some examples, the power of the heater is adjusted according to the rate of decrease of the natural gas temperature: when the temperature drops suddenly, the heater is operated at high power to quickly increase the temperature; after the temperature stabilizes, the heater is operated at low power to maintain the target temperature.

[0013] In some examples, the intelligent control system implements a multi-level energy scheduling strategy: giving priority to meeting internal demand of the voltage regulating station; when the energy storage is fully loaded, the remaining electricity is connected to the grid to participate in peak regulation; and optimizing grid-connected power transmission according to grid demand response.

[0014] In some examples, the intelligent control system includes an energy efficiency monitoring module configured to: calculate carbon emissions from the pressure regulation process in real time; and generate an energy efficiency report based on natural gas pressure, temperature, and electricity consumption data. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the block diagram of the surplus energy utilization system of the natural gas pressure regulating station.

[0016] Figure 2 It is a flow chart of the utilization of surplus energy in a natural gas pressure regulating station.

[0017] Figure 3 This is a schematic diagram of electrical energy distribution. DETAILED DESCRIPTION

[0018] like Figure 1 、 Figure 2As shown in the figure, the waste energy utilization system of the natural gas pressure regulating station includes a waste energy recovery device, a heater, an intelligent control system, and an energy storage system.

[0019] The waste energy recovery device is installed at the outlet of the natural gas pressure regulation, and is used to capture the pressure energy released during the pressure regulation process and convert it into electric energy. It includes an expander and a generator: the expander has the ability to handle large flow rates and high pressure differences of natural gas, and converts the pressure energy into mechanical energy through the expansion process; the generator further converts the mechanical energy into electric energy, and its maximum power generation can be set according to actual needs (for example, 500kW).

[0020] The heater heats up the natural gas through electric heating or heat exchange to compensate for the temperature drop caused by the pressure reduction during the pressure regulation and transmission processes.

[0021] The energy storage system (with a capacity that can be designed as 500kWh) is responsible for storing the electric energy generated by the waste energy recovery device. Among them: the battery is used for short-term electric energy storage and can quickly respond to the instantaneous power consumption requirements of the pressure regulating station or the power grid; the liquid air energy storage module converts the excess electric energy into low-temperature liquid air for storage, which is suitable for long-term or large-scale energy storage, and the energy is recovered through an expander when needed.

[0022] The intelligent control system monitors the pressure and temperature parameters of the natural gas in real time through pressure sensors and temperature sensors. At the same time, it obtains the working status (such as the expander speed and power generation power) through the built-in operation status monitoring modules (including speed sensors, current monitoring units, etc.) of the waste energy recovery device (such as the expander and the generator). The PLC analyzes all the data, dynamically adjusts the output power of the waste energy recovery device, and optimizes the electric energy distribution strategy to improve the overall energy efficiency. For example: when the natural gas temperature is lower than the safety threshold, the electric energy is preferentially distributed to the heater to compensate for the temperature drop; during the low-demand period, the excess electric energy is preferentially stored in the battery or the liquid air system; when the energy storage is full, the remaining electric energy can be incorporated into the power grid to participate in peak shaving to improve the energy utilization rate.

[0023] The intelligent control system also includes an energy efficiency monitoring module, which is configured to: calculate the carbon emissions during the pressure regulation process in real time based on the natural gas flow rate, composition, and power generation efficiency data; generate a report including energy efficiency indicators according to the data of pressure sensors, temperature sensors, power consumption, and equipment operation duration; adjust the output power of the waste energy recovery device through the PID control algorithm to optimize the system energy efficiency. Among them, the energy efficiency monitoring module is a software program running on an industrial computer, and its data interface is integrated with other modules of the intelligent control system.

[0024] Figure 3 The energy recovery process of the waste energy utilization system is shown. The method will be described in detail below.

[0025] S1: Natural gas pressure regulation and waste energy capture.

[0026] When natural gas enters the pressure regulating station, its pressure is usually much higher than the requirements of the downstream pipeline network. To achieve smooth pressure reduction and recover excess energy, the natural gas is directly reduced in pressure by an expander (for example, reducing the pressure from 10MPa to 3MPa), and the pressure energy is converted into mechanical energy. The expander expands the high-pressure natural gas to the target pressure (matching the needs of the downstream pipeline network), and then an energy conversion device (such as a generator) converts the mechanical energy into electrical energy. The generated electrical energy is dynamically distributed through an intelligent control system: part of the electrical energy directly drives the downstream heater to heat the natural gas to compensate for the temperature drop caused by pressure regulation and transmission; the remaining electrical energy is stored in batteries or liquid air energy storage systems, or connected to the power grid for efficient energy utilization.

[0027] S2: Dynamic compensation of gas temperature.

[0028] During the natural gas pressure regulation process, the pressure drop causes the temperature to drop sharply. To ensure that the natural gas temperature remains within the safe operating range, the system implements temperature compensation through real-time monitoring and dynamic control. The temperature sensor at the expander outlet continuously collects natural gas temperature data and transmits the signal to the intelligent control system. When the sensor detects that the natural gas temperature is lower than the safety threshold (for example, lower than 5°C), the intelligent control system starts the heater. The power of the heater is dynamically adjusted according to the temperature drop rate: if the temperature drops sharply, the heater runs at high power to quickly heat up; when the temperature approaches the target value (for example, 10°C), the power is gradually reduced until it is shut down to avoid overheating. The electric energy required for the heater is preferentially provided by the waste energy recovery device (such as the expander-generator system), forming a closed-loop energy utilization.

[0029] S3: Intelligent control and dynamic allocation of surplus energy.

[0030] The intelligent control system dynamically allocates electricity according to priority based on the real-time operating status. First, if the temperature sensor reports that the natural gas temperature is lower than the safety threshold, the system will prioritize allocating electricity to the heater to ensure that the temperature meets the standard. Secondly, when the temperature is within the normal range and there is still surplus energy, the excess electricity is stored in the energy storage device. Energy storage devices include batteries (such as lithium batteries or supercapacitors) and liquid air energy storage devices. Batteries support fast charging and discharging and are suitable for short-term energy storage (such as emergency power supply or peak power consumption within the pressure regulating station). Liquid air energy storage devices store excess electricity through compressed air liquefaction technology, and recover energy through expanders when needed, which is suitable for long-term energy storage needs. Finally, when the energy storage system reaches its capacity limit, the excess electricity is transmitted to the external power grid through the grid-connected interface to participate in peak regulation or auxiliary power supply, forming a multi-level energy scheduling strategy.

[0031] S4: Energy storage and efficient utilization in multiple scenarios.

[0032] The system integrates multiple energy storage technologies to achieve flexible energy scheduling and efficient utilization. The energy storage devices include batteries and liquid air energy storage devices: Battery energy storage supports fast charging and discharging and is used to meet instantaneous electricity demands (such as emergency heating or power supply during peak hours); The liquid air energy storage device stores excess electrical energy through compressed air liquefaction technology and releases energy when needed. The energy scheduling strategy first meets the internal demands of the pressure regulating station (such as heaters, control systems), and the remaining electrical energy is incorporated into the power grid to participate in peak shaving, reducing external energy dependence. During low-load periods, the system preferentially stores energy to reduce the power purchase cost from the grid; During high-demand periods, the stored energy is released to support the operation of the pressure regulating station or the power grid, enhancing overall economic efficiency.

[0033] S5: Energy efficiency monitoring and intelligent optimization.

[0034] The entire process is monitored, analyzed, and optimized in real time through an intelligent control system to ensure green and low-carbon operation. Key node data (including pressure, temperature, power consumption, energy storage status, etc.) are continuously collected, and the carbon emissions during the pressure regulating process are calculated. The intelligent control system dynamically adjusts the power output of the surplus energy recovery device, the energy storage distribution ratio, and the grid connection strategy. For example, during low heating demand periods, the load of the surplus energy recovery device is reduced to reduce equipment wear; The grid-connected power transmission is optimized according to the grid demand response (such as electricity price fluctuations). The system regularly generates energy efficiency reports, identifies bottlenecks, and proposes improvement plans (such as upgrading the efficiency of the expander or optimizing the energy storage configuration). By reducing external power dependence and reusing surplus energy, carbon emissions are reduced.

[0035] This invention significantly reduces the dependence of natural gas pressure regulating stations on the external power grid, effectively reduces operating costs and carbon emissions, and enhances the system's risk resistance ability. Especially during sudden power shortages, it can still ensure the basic operation of the pressure regulating station and ensure the stable supply of natural gas.

Claims

1. A waste energy utilization system for a natural gas pressure regulating station, characterized in that, include: The residual energy recovery device is installed at the natural gas pressure regulating outlet to capture the pressure energy released during the pressure regulation process and convert it into electrical energy; Heaters, which heat the natural gas by electrical heating or heat exchange to compensate for the temperature drop caused by pressure reduction during pressure regulation and transmission; an energy storage system configured to store the electric energy generated by the surplus energy recovery device; An intelligent control system dynamically adjusts the output power of the surplus energy recovery device based on the pressure and temperature of natural gas and the operating status of the surplus energy recovery device, controls the compensatory heating of the heater, and distributes the electric energy in multiple stages.

2. The energy recovery system for natural gas pressure regulating station according to claim 1, characterized in that The surplus energy recovery device includes: an expander, which converts the pressure energy of high-pressure natural gas into mechanical energy through an expansion process; and a generator, which converts the mechanical energy into electrical energy.

3. The waste energy utilization system of the natural gas pressure regulating station according to claim 2, characterized in that, The expander reduces the pressure of natural gas from 10 MPa to 3 MPa.

4. The waste energy utilization system of the natural gas pressure regulating station according to claim 1, characterized in that The energy storage system includes: a battery for short-term energy storage and a liquid air energy storage module for long-term energy storage.

5. The system according to claim 4, wherein The energy storage system is configured to supply power to the pressure regulating station through the battery or liquid air energy storage module when there is a power shortage, ensuring that the natural gas temperature does not fall below a safety threshold and the pressure is stable.

6. The waste energy utilization system for natural gas pressure regulating station according to claim 2, wherein The intelligent control system comprises: Pressure sensor and temperature sensor to monitor natural gas pressure and temperature in real time; An operating status monitoring module, comprising a speed sensor and a current monitoring unit, for monitoring the speed of the expander and the power generated by the generator; The PLC controller dynamically adjusts the output power of the surplus energy recovery device based on the monitoring data of the pressure sensor, the temperature sensor and the operation status monitoring module, and optimizes the power distribution strategy.

7. The waste energy utilization system of the natural gas pressure regulating station according to claim 6, characterized in that, The PLC controller executes the following control logic: when the natural gas temperature is lower than 5°C, electric energy is preferentially allocated to the heater for temperature rise compensation; when the temperature approaches 10°C, the heater power is gradually reduced until it is shut down; during periods of low demand, excess electric energy is preferentially stored in the battery or liquid air energy storage module.

8. The waste energy utilization system of a natural gas pressure regulating station according to claim 7, characterized in that, The power of the heater is adjusted according to the rate of decrease of the natural gas temperature: when the temperature drops suddenly, it runs at high power to quickly heat up; after the temperature stabilizes, it runs at low power to maintain the target temperature.

9. The waste energy utilization system of the natural gas pressure regulating station according to claim 1, characterized in that, The intelligent control system implements a multi-level energy dispatching strategy: giving priority to meeting the internal demand of the voltage regulating station; when the energy storage is fully loaded, the remaining electricity is connected to the grid to participate in peak regulation; and the grid-connected power transmission is optimized according to the grid demand response.

10. The waste energy utilization system of the natural gas pressure regulating station according to claim 1, characterized in that, The intelligent control system includes an energy efficiency monitoring module configured to: calculate the carbon emissions of the pressure regulation process in real time; and generate an energy efficiency report based on natural gas pressure, temperature, and electricity consumption data.

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