A mobile energy recovery device and method for compressed air system in a factory

Abstract

A mobile energy recovery device and method for a compressed air system in a factory, including establishing a mobile airflow energy recovery device based on an air motor and a magnetic induction power generation module; step 2: on the basis of the aforementioned energy recovery device, establishing a working condition optimization system adapted to the exhaust characteristics of the pressure gas tank of the compressed air system in the factory; step 3: combining the aforementioned energy recovery device and the working condition optimization system to establish an energy recovery method for decompression and exhaust of the pressure gas tank of the compressed air system in the factory; step 4: applying this method, performing energy recovery and realizing the utilization of the recovered energy for the decompression and exhaust process of the pressure gas tank of the compressed air system in the target factory. The present invention can utilize the kinetic energy of the airflow released during the decompression and exhaust process of the pressure gas tank to generate electrical energy and store it in a battery, thereby realizing energy recovery and facilitating utilization.

Description

Technical Field

[0001] The invention belongs to the technical field of air compressor energy recovery, and in particular relates to a mobile energy recovery device and method for a compressed air system in a factory. Background Art

[0002] The compressed air system in the hydropower station is an important auxiliary equipment of the hydropower station, including air compression devices, pressure gas tanks, pipe valves and measurement and control components. The internal pressure of the commonly used medium-pressure container is generally 2.5~6.3MPa. The compressed air system in the plant mainly supplies air to the oil pressure tank pressure tank attached to the oil pressure device of the turbine generator set, thereby providing dedicated operating energy for the turbine speed control system.

[0003] In the routine maintenance of the compressed air system or the oil pressure device of the unit in the factory, decompression and exhaust of the pressure gas tank is an essential and important safety technical measure for equipment maintenance, and it is implemented frequently. The current general practice is to open the exhaust valve of the pressure gas tank to directly vent the compressed air in the tank and exhaust the pressure to zero. This practice causes a certain degree of airflow kinetic energy waste and serious noise pollution. At the same time, during the decompression and exhaust process, the tank air pressure gradually decreases, but because the exhaust process is affected by many factors, its exhaust characteristics are relatively complex, and the exhaust pressure is also volatile.

[0004] An air motor is a pneumatic transmission device that can convert compressed air pressure energy into rotational mechanical energy output. It is widely used in various industries and mainly has two types: vane type and piston type. Currently, various types of air motors usually require a stable pressure and flow of compressed air to achieve the rated output, and their rated working pressure is usually 0.6-0.8MPa.

[0005] In the prior art, there is no systematic description of the decompression of the compressed air tank in the compressed air system of the hydropower station during maintenance to recover the energy of the exhaust gas. There is currently a description of using compressed air to drive the air motor to generate electricity, such as the invention with the publication number CN110829719A, which discloses a power generation combination of a pneumatic motor and a generator. However, the invention only proposes the relevant concept and has not yet clearly explained the specific application details. It is difficult to directly apply it to the compressed air system in the plant to realize the recovery of airflow kinetic energy. Moreover, the invention cannot realize the function of optimizing the energy recovery working condition for the complex exhaust characteristics of the compressed air system in the plant, which gradually decreases and changes the air pressure. Summary of the invention

[0006] In view of the technical problems existing in the background technology, the present invention provides a mobile energy recovery device and method for a compressed air system in a factory, which can use the kinetic energy of the airflow released during the decompression and exhaust process of the pressure gas tank to generate electrical energy and store it in a battery, thereby realizing energy recovery and facilitating utilization.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve:

[0008] A mobile energy recovery device for a compressed air system in a factory comprises a mobile platform, on which an energy recovery device and an energy storage device are arranged, the energy recovery device comprises an air motor and a generator, the air motor is used to drive the generator rotor to rotate, the air motor is detachably connected to the compressed air system through a main air pipe, and a pressure reducing valve is arranged on the main air pipe; the energy storage device comprises a battery, and the electric energy generated by the generator is stored in the battery.

[0009] In a preferred solution, there are multiple energy recovery devices, and the energy recovery devices are connected to the same main gas pipe through branch pipes.

[0010] In a preferred embodiment, the mobile platform is a wheeled motorized cart.

[0011] In a preferred embodiment, the energy recovery device is a blade-type or piston-type device that can be driven by a compressed air flow to achieve rotational mechanical energy output.

[0012] A recovery method of a mobile energy recovery device for a compressed air system in a factory, characterized by:

[0013] Step 1: When the compressed air system is under maintenance, move the mobile energy recovery device to the side of the pressure gas tank and connect the main air pipe to the exhaust port of the pressure gas tank;

[0014] Step 2: Open the pressure reducing valve, the compressed gas in the pressure gas tank works on the energy recovery device, the air motor of the energy recovery device drives the generator rotor to rotate, converts kinetic energy into electrical energy and stores it in the energy storage device;

[0015] Step 3: The energy storage device is detachably arranged on the mobile platform, and when the energy storage device is fully charged, it is replaced with another energy storage device.

[0016] In the preferred solution, a logic control valve is installed on each branch pipe to improve the recovery method of step 2 as follows:

[0017] Step 2.1, the pressure reducing valve included in the mobile energy recovery device calculates the real-time outlet flow rate through the inlet and outlet pressure parameters, as shown in formula (1):

[0018] (1)

[0019] Where: q rv ( t ) is the time at which the pressure reducing valve outlet t The gas flow rate;

[0020] P 1 ( t ), P 2 ( t ) are the inlet and outlet of the pressure reducing valve at time t The pressure;

[0021] f rv {} is the flow-pressure relationship function of the pressure reducing valve;

[0022] Step 2.2, the total number of energy recovery devices included in the mobile energy recovery device, that is, the number of configured air motors combined with magnetic induction generating coils, is determined by the maximum exhaust pressure of the target pressure tank combined with the relevant parameters of the pressure reducing valve and the air motor, as shown in formula (2):

[0023] (2)

[0024] Where: n m is the total number of energy recovery devices connected in parallel in the system, that is, the number of air motors combined with magnetic induction generating coils configured;

[0025] q rvm The maximum gas flow rate at the outlet of the pressure reducing valve;

[0026] q ae is the rated air consumption of the air motor;

[0027] is the ceiling rounding function;

[0028] P 1m The maximum exhaust pressure of the target pressure gas tank is the maximum pressure at the inlet of the pressure reducing valve;

[0029] P 2 is the pressure relief valve outlet pressure, in the present invention P 2 The value is 0.6MPa;

[0030] Step 2.3, the mobile energy recovery device includes a logic control valve, which is used to match the energy recovery working condition with the exhaust condition of the pressure gas tank. The air motor is turned off or on considering the rated air consumption of the air motor to control the number of energy recovery devices in working state. The control logic of the logic control valve is shown in formula (3).

[0031] (3)

[0032] Where:n w ( t ) is the time t The number of air motors that should be in operation;

[0033] n c ( t ) is the time for the logic pipeline t The number of air motors that should be shut down;

[0034] is a rounding function subject to rounding rules;

[0035] Step 2.4, for the convenience of estimation, the energy recovery devices in operation are approximately regarded as being in the rated working state, and the real-time power generation and total power generation of the mobile energy recovery device can be estimated by formula (4):

[0036] (4)

[0037] Where: W ( t ) is the system at time t Total power generation capacity;

[0038] W ae is the rated output power of the air motor;

[0039] is the power generation efficiency of the magnetic induction generating coil;

[0040] E is the total power generation of the system;

[0041] Step 2.5: Calculate the maximum gas flow rate at the outlet of the pressure reducing valve based on equations (1) and (2): q rvm , and calculate the number of air motors of each model to be configured according to the rated air consumption parameters of the alternative air motors; the air motor selection is realized by taking the carrying capacity of the wheeled mobile platform as the restriction condition and the working efficiency of the air motor as the selection index. The logic is shown in formula (5):

[0042] (5)

[0043] Where: Max ( ) is the maximum value function;

[0044] G is the weight of the corresponding model of air motor;

[0045] M e It is the total weight of the device including modules and accessories except the air motor.

[0046] B m is the maximum load-bearing weight of the mobile platform.

[0047] Step 2.6, when the energy recovery device is working, according to the real-time exhaust condition of the pressure gas tank, the adjustment plan is analyzed according to equations (1) and (3), and the energy recovery device is closed or opened through the logic pipeline, so as to optimize the energy recovery working condition of the device;

[0048] When the compressed air system maintenance in the factory is completed and the pressure tank exhaust stops or the pressure tank exhaust pressure is less than the rated pressure of the air motor 0.6MPa, it is considered that the energy recovery device has completed its work, and then the device is moved away from the compressed air system maintenance site in the factory.

[0049] This patent can achieve the following beneficial effects:

[0050] 1. It can effectively recover the kinetic energy of the air released during the decompression and exhaust process of the conventional medium-pressure gas tank during the routine maintenance of the compressed air system in the hydropower station, and store the recovered energy in the battery in the form of electrical energy, which is convenient for secondary utilization.

[0051] 2. The mobile energy recovery device has good mobility and can be moved between multiple pressure gas tanks in the power plant. The connection method between the device and the exhaust hole of the pressure gas tank is simple and does not affect the normal maintenance work of the compressed air system in the hydropower station.

[0052] 3. The energy recovery method of the mobile energy recovery device can achieve the matching of energy recovery conditions with the exhaust characteristics of the pressure gas tank during the maintenance of the compressed air system in the factory, and automatically adjust and optimize the energy recovery conditions according to the air flow release of the pressure gas tank. This method helps to reduce the loss of energy recovery and improve the recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0054] Figure 1 A layout diagram of a mobile energy recovery device provided by the present invention;

[0055] Figure 2 Improved diagram of the mobile energy recovery device provided by the present invention (with a logic control valve installed);

[0056] Figure 3 The present invention is a flow chart for the use of the mobile energy recovery device. DETAILED DESCRIPTION

[0057] The preferred solution is Figure 1 to Figure 2As shown, a mobile energy recovery device for a compressed air system in a factory includes a mobile platform, an energy recovery device and an energy storage device are arranged on the mobile platform, the energy recovery device includes an air motor and a generator, the air motor is used to drive the generator rotor to rotate, the air motor is detachably connected to the compressed air system through a main air pipe, and a pressure reducing valve is arranged on the main air pipe; the energy storage device includes a battery, and the electric energy generated by the generator is stored by the battery. The energy storage device is a combination of an electric voltage stabilizer and a detachable battery, and includes related charging and discharging, a stabilizing card seat and a mobile handle and other accessories. Based on the prior art, a voltage stabilizer refers to a device that can stabilize the output voltage of the energy recovery device to the rated charging voltage of the battery; the battery includes but is not limited to lead-acid batteries, lithium iron batteries, sodium ion batteries and other rechargeable and dischargeable batteries, so as to store the electricity generated by the device recovering the kinetic energy of the airflow. After the battery is fully charged, it can be removed from the device and carried by the mobile handle to move to other places where electricity is used, so as to facilitate the use of recovered energy.

[0058] Furthermore, there are multiple energy recovery devices, and the energy recovery devices are connected to the same main gas pipe through branch pipes.

[0059] Further, the mobile platform is a wheeled motorized cart. In this embodiment, the wheeled motorized cart does not exceed 200 kg.

[0060] Furthermore, the energy recovery device is a blade-type or piston-type device that can be driven by compressed air flow to achieve rotational mechanical energy output. The energy recovery device is a combination of an air motor and a magnetic induction generator coil, and an air motor with noise reduction and silencing function is usually selected; the magnetic induction generator coil refers to a device that generates electricity by cutting a fixed magnetic field through a conductor based on the law of electromagnetic induction and the law of electromagnetic force; the energy recovery device is connected to the air motor drive shaft and the magnetic induction generator coil conductor rotor, so that when the pressure gas tank exhaust is introduced and the air motor is driven to run, the conductor is driven to rotate and cut the magnetic flux lines to generate electricity.

[0061] like Figure 3 As shown, preferably, the recovery method of the mobile energy recovery device of the compressed air system in the factory comprises the following steps:

[0062] Step 1: When the compressed air system is under maintenance, move the mobile energy recovery device to the side of the pressure gas tank and connect the main air pipe to the exhaust port of the pressure gas tank;

[0063] Step 2: Open the pressure reducing valve, the compressed gas in the pressure gas tank works on the energy recovery device, the air motor of the energy recovery device drives the generator rotor to rotate, converts kinetic energy into electrical energy and stores it in the energy storage device;

[0064] Step 3: The energy storage device is detachably arranged on the mobile platform, and when the energy storage device is fully charged, it is replaced with another energy storage device.

[0065] Furthermore, a logic control valve is installed on each branch pipe. The logic control valve is a regulating valve controlled by a controller. The controller is preferably a PLC or a single-chip microcomputer. The recovery method of step 2 is improved to establish a working condition optimization system adapted to the exhaust characteristics of the pressure gas tank of the compressed air system in the factory, which can realize the function of automatically adjusting and optimizing the energy recovery working condition according to the airflow release of the pressure gas tank. The method is as follows:

[0066] Step 2.1, such as Figure 3 As shown, in view of the fact that the exhaust pressure of the pressure gas tank changes from high to low during the exhaust process of the compressed air system in the factory, and is generally higher than the rated working pressure of the conventional air motor of 0.6MPa, it is considered to first use a pressure reducing valve to reduce the exhaust pressure of the pressure gas tank to 0.6MPa, and then control the opening and closing of the valve through control logic according to the change of the outlet flow of the pressure reducing valve to increase or decrease the working number of the parallel energy recovery device, so as to achieve the matching of the energy recovery working condition and the exhaust characteristics of the pressure gas tank. The pressure reducing valve included in this mobile energy recovery device calculates the real-time outlet flow through the inlet and outlet pressure parameters, as shown in formula (1):

[0067] (1)

[0068] Where: q rv ( t ) is the time at which the pressure reducing valve outlet t The gas flow rate;

[0069] P 1 ( t ), P 2 ( t ) are the inlet and outlet of the pressure reducing valve at time t The pressure;

[0070] f rv {} is the flow-pressure relationship function of the pressure reducing valve;

[0071] Step 2.2, the total number of energy recovery devices included in the mobile energy recovery device, that is, the number of configured air motors combined with magnetic induction generating coils, is determined by the maximum exhaust pressure of the target pressure tank combined with the relevant parameters of the pressure reducing valve and the air motor, as shown in formula (2):

[0072] (2)

[0073] Where:n m is the total number of energy recovery devices connected in parallel in the system, that is, the number of air motors combined with magnetic induction generating coils configured;

[0074] q rvm The maximum gas flow rate at the outlet of the pressure reducing valve;

[0075] q ae is the rated air consumption of the air motor;

[0076] is the ceiling rounding function;

[0077] P 1m is the maximum exhaust pressure of the target pressure gas tank, i.e., the maximum pressure at the inlet of the pressure reducing valve. In the present invention, the maximum pressure value of the pressure gas tank is taken;

[0078] P 2 is the pressure relief valve outlet pressure, in the present invention P 2 The value is 0.6MPa;

[0079] Step 2.3, the mobile energy recovery device includes a logic control valve, which is used to match the energy recovery working condition with the exhaust condition of the pressure gas tank. The air motor is turned off or on considering the rated air consumption of the air motor to control the number of energy recovery devices in working state. The control logic of the logic control valve is shown in formula (3).

[0080] (3)

[0081] Where: n w ( t ) is the time t The number of air motors (energy recovery devices) that should be in operation;

[0082] n c ( t ) is the time for the logic pipeline t The number of air motors (energy recovery devices) that should be shut down;

[0083] is a rounding function subject to rounding rules;

[0084] Step 2.4, for the convenience of estimation, the energy recovery devices in operation are approximately regarded as being in the rated working state, and the real-time power generation and total power generation of the mobile energy recovery device can be estimated by formula (4):

[0085] (4)

[0086] Where: W ( t ) is the system at time t Total power generation capacity;

[0087] W ae is the rated output power of the air motor;

[0088] is the power generation efficiency of the magnetic induction power generation coil, which is usually greater than 0.9 according to the prior art;

[0089] E is the total power generation of the system;

[0090] Step 2.5: Calculate the maximum gas flow rate at the outlet of the pressure reducing valve based on equations (1) and (2): q rvm , and calculate the number of air motors of each model to be configured according to the rated air consumption parameters of the alternative air motors; the air motor selection is realized by taking the carrying capacity of the wheeled mobile platform as the restriction condition and the working efficiency of the air motor as the selection index. The logic is shown in formula (5):

[0091] (5)

[0092] Where: Max ( ) is the maximum value function;

[0093] G is the weight of the corresponding model of air motor;

[0094] M e It is the total weight of the device including modules and accessories except the air motor.

[0095] B m is the maximum load-bearing weight of the mobile platform.

[0096] Step 2.6, when the energy recovery device is working, according to the real-time exhaust condition of the pressure gas tank, the adjustment plan is analyzed according to equations (1) and (3), and the energy recovery device is closed or opened through the logic pipeline, so as to optimize the energy recovery working condition of the device;

[0097] When the compressed air system maintenance in the factory is completed and the pressure tank exhaust stops or the pressure tank exhaust pressure is less than the rated pressure of the air motor 0.6MPa, it is considered that the energy recovery device has completed its work, and then the device is moved away from the compressed air system maintenance site in the factory.

[0098] Embodiment 1:

[0099] The compressed air system in a hydropower station needs to be repaired. Its pressure gas tank consists of two connected 15m 3 The capacity of the tank is rated at 4.0 MPa. The mobile energy recovery device and method of the present invention are applied to the compressed air system in the plant.

[0100] (1) Example of energy recovery device preparation process:

[0101] For the compressed air system pressure tank in the target plant, the maximum outlet flow rate of the pressure reducing valve outlet is calculated to configure the energy recovery device. That is, when the inlet pressure of the pressure reducing valve is 4.0MPa and the outlet pressure is 0.6MPa, the outlet flow rate is calculated to be 270~295m according to the working characteristic parameters of the pressure reducing valve. 3 / h. Based on this data, the air motor was selected and a certain type of piston air motor was finally selected. Its parameters include: air consumption 0.985 m 3 / min; rated power 1.12kW, maximum output speed 360rpm, weight 20kg.

[0102] Therefore, according to the calculation of formula (2), the energy recovery device in this example should be equipped with 5 air motors of this model. After the energy recovery device is prepared, the device is connected to the pressure gas tank and put into energy recovery work.

[0103] (2) Example of operating condition adjustment of energy recovery device

[0104] During the operation of the energy recovery device, two typical working conditions are selected to demonstrate the working parameters of the energy recovery device and the process of adjusting them according to the exhaust conditions of the pressure gas tank.

[0105] Working condition 1: When the pressure reducing valve inlet pressure is 3.0MPa and the outlet pressure is 0.6MPa, the calculated outlet flow rate is 240~265m 3 / h. According to formula (3), the number of energy recovery devices in operation is 4, that is, the logic pipeline needs to close the air flow input of one air motor (energy recovery device). At this time, the real-time power generation of the energy recovery device is 4.256 kW (the power generation efficiency coefficient of the magnetic induction generating coil is 0.95).

[0106] Working condition 2: When the pressure reducing valve inlet pressure is 2.0MPa and the outlet pressure is 0.6MPa, the calculated outlet flow rate is 155~180m 3 / h, according to formula (3), the number of energy recovery devices in working state is 3, that is, the logic pipeline needs to close the airflow input of 2 air motors (energy recovery devices), and the real-time power generation of the energy recovery device is 3.192kw (the power generation efficiency coefficient of the magnetic induction generating coil is 0.95). At this time, in order to cooperate with the reduction of the exhaust pressure of the pressure gas tank, the device closes one more energy recovery device than the working condition 1, which realizes the optimal regulation of energy recovery.

[0107] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A mobile energy recovery device for a compressed air system in a factory, characterized by: It includes a mobile platform, on which an energy recovery device and an energy storage device are arranged, the energy recovery device includes an air motor and a generator, the air motor is used to drive the generator rotor to rotate, the air motor is detachably connected to the compressed air system through a main air pipe, and a pressure reducing valve is arranged on the main air pipe; the energy storage device includes a battery, and the electric energy generated by the generator is stored in the battery; There are multiple energy recovery devices, and the energy recovery devices are connected to the same main gas pipe through branch pipes; The mobile platform is a wheeled motorized cart; The energy recovery device is a blade or piston type device that can be driven by compressed air flow to achieve rotational mechanical energy output; The recovery method of the mobile energy recovery device of the compressed air system in the factory comprises the following steps: Step 1: When the compressed air system is under maintenance, move the mobile energy recovery device to the side of the pressure gas tank and connect the main air pipe to the exhaust port of the pressure gas tank; Step 2: Open the pressure reducing valve, the compressed gas in the pressure gas tank works on the energy recovery device, the air motor of the energy recovery device drives the generator rotor to rotate, converts kinetic energy into electrical energy and stores it in the energy storage device; Step 3: The energy storage device is detachably arranged on the mobile platform, and when the energy storage device is fully charged, another energy storage device is replaced; Install a logic control valve on each branch pipe to improve the recovery method in step 2 as follows: Step 2.1, the pressure reducing valve included in the mobile energy recovery device calculates the real-time outlet flow rate through the inlet and outlet pressure parameters, as shown in formula (1): （1）； Where: q rv ( t ) is the time at which the pressure reducing valve outlet t The gas flow rate; P 1( t ), P 2( t ) are the inlet and outlet of the pressure reducing valve at time t The pressure; f rv {} is the flow-pressure relationship function of the pressure reducing valve; Step 2.2, the total number of energy recovery devices included in the mobile energy recovery device, that is, the number of configured air motors combined with magnetic induction generating coils, is determined by the maximum exhaust pressure of the target pressure tank combined with the relevant parameters of the pressure reducing valve and the air motor, as shown in formula (2): （2）； Where: n m is the total number of energy recovery devices connected in parallel in the system, that is, the number of air motors combined with magnetic induction generating coils configured; q rvm The maximum gas flow rate at the outlet of the pressure reducing valve; q ae is the rated air consumption of the air motor; is the ceiling rounding function; P 1m The maximum exhaust pressure of the target pressure gas tank is the maximum pressure at the inlet of the pressure reducing valve; P 2 is the outlet pressure of the pressure reducing valve; Step 2.3, the mobile energy recovery device includes a logic control valve, which is used to match the energy recovery working condition with the exhaust condition of the pressure gas tank, and to close or open the air motor considering the rated air consumption of the air motor to control the number of energy recovery devices in working state. The control logic of the logic control valve is shown in formula (3); （3）； Where: n w ( t ) is the time t The number of air motors that should be in operation; n c ( t ) is the time for the logic pipeline t The number of air motors that should be shut down; is a rounding function subject to rounding rules; Step 2.4, for the convenience of estimation, the energy recovery devices in operation are approximately regarded as being in the rated working state, and the real-time power generation and total power generation of the mobile energy recovery device can be estimated by formula (4): （4）； Where: W ( t ) is the system at time t Total power generation capacity; W ae is the rated output power of the air motor; is the power generation efficiency of the magnetic induction generating coil; E is the total power generation of the system; Step 2.5: Calculate the maximum gas flow rate at the outlet of the pressure reducing valve based on equations (1) and (2): q rvm , and calculate the number of air motors of each model to be configured according to the rated air consumption parameters of the alternative air motors; the air motor selection is realized by taking the carrying capacity of the wheeled mobile platform as the restriction condition and the working efficiency of the air motor as the selection index. The logic is shown in formula (5): （5）； Where: Max ( ) is the maximum value function; G is the weight of the corresponding model of air motor; M e It is the total weight of the device’s modules and accessories excluding the air motor; B m is the maximum load-bearing weight of the mobile platform; Step 2.6, when the energy recovery device is working, according to the real-time exhaust condition of the pressure gas tank, the adjustment plan is analyzed according to equations (1) and (3), and the energy recovery device is closed or opened through the logic pipeline, so as to optimize the energy recovery working condition of the device; When the compressed air system maintenance in the factory is completed and the pressure tank exhaust stops or the pressure tank exhaust pressure is less than the rated pressure of the air motor 0.6MPa, it is considered that the energy recovery device has completed its work, and then the device is moved away from the compressed air system maintenance site in the factory.

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