Low-concentration gas mixing system

Abstract

The utility model discloses a low-concentration gas mixing system. The low-concentration gas mixing system comprises a mixer, a gas inlet pipeline, a to-be-mixed gas inlet pipeline and a controller, the gas inlet pipeline and the to-be-doped gas inlet pipeline are respectively connected with the gas inlet end of the mixer so as to input low-concentration gas and to-be-doped gas; the gas outlet end of the mixer is provided with a sensor for detecting the concentration and / or flow of mixed gas; regulating valves are arranged on the gas inlet pipeline and the to-be-doped gas inlet pipeline and are used for regulating the flow of gas in the respective pipelines; the controller is in signal connection with the sensors and the adjusting valves, and the controller controls the opening degree of the adjusting valves according to signals transmitted by the sensors, so that the concentration and the flow of gas entering the mixer in each pipe are controlled, and the concentration and / or the flow of the mixed gas are / is stabilized at target values preset by the system. According to the device, automatic mixing is realized, and the problems of overlarge pressure loss and unstable precision control in the gas mixing process caused by manual gas mixing control in the prior art are solved.

Description

Technical Field

[0001] The utility model belongs to the field of gas mixing, and particularly relates to a low-concentration gas mixing system. Background Art

[0002] Since the volume fractions of the gas extracted from the mine are different, in related fields such as gas utilization and chemical synthesis, in order to make full use of the coalbed methane with a low volume fraction, sometimes it is necessary to mix two or more kinds of gas with different volume fractions of gas to form a new volume fraction of gas for use. It is required that the volume fraction of the mixed gas is stable and the pressure fluctuation is small. However, most of the existing technical solutions remain in the manual control stage, resulting in problems such as excessive pressure loss and unstable precision control during the gas mixing process. Therefore, a more reliable and automatically controlled gas mixing control system is needed to control the gas mixing process, so that the volume fraction of the mixed gas is more stable and the pressure loss is smaller. Summary of the Utility Model

[0003] Aiming at the above deficiencies of the existing technology, the purpose of the utility model is to provide a low-concentration gas mixing system, which can reliably and automatically control gas mixing, make the volume fraction of the mixed gas more stable and the pressure loss smaller, and effectively solve the problems of excessive pressure loss and unstable precision control during the gas mixing process caused by manual control of gas mixing in the existing technology.

[0004] The technical scheme adopted is as follows:

[0005] The utility model discloses a low-concentration gas mixing system, which includes a mixer, a gas inlet pipeline for gas, a gas inlet pipeline for the gas to be mixed, and a controller. The mixer is configured to have an inlet end for receiving gas input and an outlet end for outputting the mixed gas; the gas inlet pipeline for gas and the gas inlet pipeline for the gas to be mixed are respectively connected to the inlet end of the mixer for inputting low-concentration gas and the gas to be mixed into the mixer for mixing; an outlet sensor is arranged on the outlet end of the mixer for detecting the gas concentration and / or flow rate of the low-concentration gas and the gas to be mixed after mixing in the mixer; inlet control valves are respectively arranged on the gas inlet pipeline for gas and the gas inlet pipeline for the gas to be mixed for adjusting the flow rate of the gas in the pipeline and the flow rate of the gas to be mixed in the pipeline; the controller forms a signal connection with the outlet sensor and the inlet control valves, and can control the valve opening degree of the inlet control valves according to the detection signals transmitted by the sensor, so as to control the flow rates of the gas in the gas inlet pipeline and the gas to be mixed in the gas inlet pipeline for the gas to be mixed entering the mixer, so that the concentration and / or flow rate of the mixed gas are stabilized at the target value preset by the system.

[0006] In the above solution, since the controller is respectively in signal connection with the sensor and the intake air regulating valve, when the sensor detects that the concentration and flow rate of the mixed gas are greater than the target values preset by the system, at this time, the controller controls the concentration and flow rate of the gas entering the mixer by reducing the valve opening of the regulating valve on the gas intake pipeline of the gas and / or increasing the valve opening of the regulating valve on the intake pipeline of the gas to be mixed, so that the concentration of the mixed gas begins to decrease and finally equals the target value; when the concentration and flow rate of the mixed gas are less than the target values preset by the system, at this time, the controller controls the concentration and flow rate of the gas entering the mixer by increasing the valve opening of the regulating valve on the gas intake pipeline of the gas and / or reducing the valve opening of the regulating valve on the intake pipeline of the gas to be mixed, so that the concentration of the mixed gas begins to increase and finally equals the target value; through this automated dynamic regulation, the concentration and / or flow rate of the mixed gas will always be stable at the target values preset by the system, making the volume fraction of the mixed gas more stable and the pressure fluctuation smaller.

[0007] In the disclosed low-concentration gas mixing system, intake air sensors are also provided on the gas intake pipeline of the gas and the intake pipeline of the gas to be mixed, for detecting whether the concentration and flow rate of the gas in their respective pipelines entering the mixer meet the standards; when the detection is qualified, the gas in the pipeline enters the mixer, and when the detection is unqualified, the gas in the pipeline is emptied.

[0008] The intake air sensors provided in the above solution detect the gas flow rate and concentration in the pipeline. In order to ensure that the gas concentration and flow rate entering the mixer meet the standards and accelerate the gas mixing process in the mixer, thereby shortening the time required for the concentration and flow rate of the mixed gas to reach the target values preset by the system, and further improving the work efficiency.

[0009] In the disclosed low-concentration gas mixing system, opening and closing valves are also provided on the gas intake pipeline of the gas and the intake pipeline of the gas to be mixed. The opening and closing valves are in signal connection with the controller. The controller controls the opening and closing of the valves of the opening and closing valves to communicate and cut off with the mixer, and controls the opening of the valves of the opening and closing valves to allow the gas to enter the mixer when the gas concentration and flow rate in the pipeline meet the standards, and controls the closing of the valves of the opening and closing valves to empty the gas when the gas concentration and flow rate in the pipeline do not meet the standards.

[0010] In the above solution, the opening and closing valve is used to control the gas in the pipe from entering the mixer, and the intake air regulating valve is used to control the flow rate of the gas in the pipe entering the mixer. In the initial state, the opening and closing valve and the intake air regulating valve are in the closed state. When low-concentration gas and the gas to be blended are respectively introduced, the intake air sensors provided on the pipeline detect the flow rate and concentration of the gas in their respective pipes in real time, and transmit the detection signals to the controller. The controller receives the detection signals and determines whether the concentration and flow rate of the gas to enter the mixer meet the standards. If they meet the standards, the controller controls the opening of the valves of the opening and closing valve and the intake air regulating valve, and the gas in the pipe enters the mixer; if they do not meet the standards, the opening and closing valve and the intake air regulating valve continue to remain in the closed state, and the gas in the pipe is emptied. At the same time, the qualified gas in the pipe entering the mixer is blended. The outlet gas sensor provided at the outlet end of the mixer detects the concentration and / or flow rate of the blended gas, and transmits the detection signals to the controller. After receiving the detection signals, the controller further determines whether the concentration and / or flow rate of the blended gas conforms to the target value preset by the system. When it conforms, the valve opening of the intake air regulating valve remains unchanged; when it does not conform or fluctuates, the controller controls the valve opening of the intake air regulating valve to adjust the concentration and / or flow rate of the blended gas by changing the flow rate of the gas entering the mixer, so that it is stabilized at the target value preset by the system.

[0011] In the disclosed low-concentration gas blending system, it further includes an emptying pipeline, which is respectively arranged on the gas intake pipeline for low-concentration gas and the gas intake pipeline for the gas to be blended, and is used to discharge the gas in the respective pipes of the gas intake pipeline for low-concentration gas and the gas intake pipeline for the gas to be blended when the concentration and flow rate do not meet the standards. An emptying regulating valve is provided on the emptying pipeline, and the emptying regulating valve is signal-connected to the controller. The controller can control the opening and closing of the valve of the emptying regulating valve, and opens the valve to allow the gas to be discharged through the emptying pipe during emptying, and closes the valve when not emptying.

[0012] In the disclosed low-concentration gas blending system, the emptying regulating valve and the opening and closing valve are pneumatic regulating valves, and the intake air regulating valve is an electric regulating valve. The pneumatic regulating valve has a low control precision but can respond quickly, and is used for the opening and closing of the valve to control the gas in the pipe from entering the mixer, while the electric regulating valve has a high control precision and can more accurately regulate the gas flow rate in the pipe to control the flow rate of the gas in the pipe entering the mixer.

[0013] In the disclosed low-concentration gas blending system, the emptying pipeline is respectively located between the sensor on the gas intake pipeline for low-concentration gas and the intake air regulating valve, and between the sensor on the gas intake pipeline for the gas to be blended and the intake air regulating valve.

[0014] In the disclosed low-concentration gas blending system, the gas intake pipeline for the gas to be blended is an air and / or exhausted air intake pipeline.

[0015] In the disclosed low-concentration gas mixing system, the sensors include a multi-parameter sensor for gas drainage and a laser methane sensor. The multi-parameter sensor for gas drainage is used to detect the gas flow rate and pressure in the pipe in real time, and the laser methane sensor is used to detect the gas concentration in the pipe in real time.

[0016] In the disclosed low-concentration gas mixing system, flame arresters are provided on the gas inlet pipe for methane and the inlet pipe for the gas to be admixed.

[0017] In the disclosed low-concentration gas mixing system, the low-concentration gas mixing system further includes an outlet pipe for the admixed gas, which is connected to the outlet end of the mixer and is used to output the gas after the low-concentration gas and the gas to be admixed in the mixer are admixed.

[0018] The beneficial effects of the present utility model are as follows:

[0019] The present utility model realizes automatic gas mixing. A signal connection is formed through the controller, the intake control valve, and the outlet gas sensor provided at the outlet end of the mixer to accurately control the gas mixing process. When the concentration and / or flow rate of the admixed gas is greater than the target value preset by the system, the valve opening of the intake control valve on the gas inlet pipe for methane is reduced and / or the opening of the intake control valve on the inlet pipe for the gas to be admixed is increased, thereby controlling the concentration and flow rate of the gas entering the mixer in the pipe, and further reducing the concentration and / or flow rate of the admixed gas to make it equal to the target value. When the concentration and / or flow rate of the admixed gas is less than the target value preset by the system, the opening of the intake control valve on the gas inlet pipe for methane is increased and / or the opening of the intake control valve on the inlet pipe for the gas to be admixed is reduced, thereby controlling the concentration and flow rate of the gas entering the mixer in the pipe, and further increasing the concentration and / or flow rate of the admixed gas to make it equal to the target value. Through the above adjustment method, the concentration and / or flow rate of the admixed gas is stabilized at the target value preset by the system, so that the gas volume fraction is more stable and the pressure fluctuation is smaller, and it can meet the usage requirements in the fields of gas utilization and chemical synthesis, etc.; and by the intake gas sensors provided on the gas inlet pipe for methane and the inlet pipe for the gas to be admixed, the concentration and flow rate of the gas in their respective pipes are detected in real time, so as to judge whether the concentration and flow rate of the gas entering the mixer meet the standards, so that the qualified gas enters the mixer for mixing, accelerating the gas mixing speed in the mixer, shortening the time required for the concentration and flow rate of the admixed gas to reach the target value preset by the system, and thus improving the mixing efficiency. In addition, the gas mixing in the prior art is manually controlled, there are problems such as excessive pressure loss and unstable precision control in the gas mixing process, while the automatic gas mixing provided by the present utility model overcomes the defects of the prior art, not only has high precision control, but also has small gas pressure loss, and is more stable at the same time, effectively solving the above problems.

[0020] The following discloses in detail a low-concentration gas mixing system provided by the present utility model in combination with the embodiments shown in the accompanying drawings and the reference numerals. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the mixing of low-concentration gas, air and / or exhausted air in the device of the present utility model.

[0022] Reference Numerals

[0023] 1 Mixer, 2 Gas inlet pipeline, 3 Gas to be mixed inlet pipeline, 4 Inlet control valve, 5 Opening and closing valve, 6 Exhaust pipeline, 7 Exhaust control valve, 8 Multi-parameter gas drainage sensor, 9 Laser methane sensor, 10 Flame arrester, 11 Mixed gas outlet pipeline, 12 Gas source, 13 Gas inlet manual valve, 14 Exhaust air main pipe, 15 First air duct, 16 First fan,

[0024] 17 Second air duct, 18 Second fan, 19 Exhaust air inlet valve, 20 First air inlet manual valve, 21 Second air inlet manual valve. Detailed Embodiment

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0026] As Figure 1As shown in the figure, the low-concentration gas mixing system of the present utility model includes: a mixer 1, a gas inlet pipeline 2 for low-concentration gas, a gas inlet pipeline 3 for the gas to be mixed, and a controller. The mixer 1 is configured to have an inlet end for receiving gas input and an outlet end for outputting the mixed gas. The gas inlet pipeline 2 for low-concentration gas and the gas inlet pipeline 3 for the gas to be mixed are respectively connected to the inlet end of the mixer 1, and are used to input the low-concentration gas and the gas to be mixed into the mixer 1 for mixing. An outlet sensor is provided at the outlet end of the mixer 1, and is used to detect the gas concentration and / or flow rate of the mixed gas of the low-concentration gas and the gas to be mixed in the mixer 1. Inlet control valves 4 are respectively provided on the gas inlet pipeline 2 for low-concentration gas and the gas inlet pipeline 3 for the gas to be mixed, and are used to adjust the flow rate of the gas in the pipeline and the flow rate of the gas to be mixed in the pipeline. The controller forms a signal connection with the outlet sensor and the inlet control valves 4, and can control the valve opening degree of the inlet control valves 4 according to the detection signal transmitted by the sensor, so as to control the flow rate of the gas in the gas inlet pipeline 2 for low-concentration gas and the gas to be mixed in the gas inlet pipeline 3 for the gas to be mixed entering the mixer 1, so that the concentration and / or flow rate of the mixed gas are stabilized at the target value preset by the system.

[0027] The present utility model realizes automatic gas mixing. By forming a signal connection among the controller, the inlet control valves 4 and the outlet sensor, the gas mixing process is accurately controlled, effectively solving the problems of excessive pressure loss and unstable precision control in the gas mixing process caused by manual control in the prior art. When the concentration and flow rate of the mixed gas are greater than the target value preset by the system, at this time, the controller reduces the valve opening degree of the inlet control valve 4 on the gas inlet pipeline 2 for low-concentration gas, so that the concentration and flow rate of the gas in the pipeline entering the mixer 1 are reduced, so that the concentration and flow rate of the mixed gas begin to decrease and finally equal the target value; the effect of dynamic balance is realized; at the same time, the valve opening degree of the inlet control valve 4 on the gas inlet pipeline 3 for the gas to be mixed can also be increased, so that the concentration and flow rate of the gas to be mixed in the pipeline entering the mixer 1 are increased, and the concentration and flow rate of the mixed gas can also begin to decrease and finally equal the target value, achieving the same effect.

[0028] When the concentration and flow rate of the mixed gas are less than the target value preset by the system, at this time, the controller increases the valve opening degree of the inlet control valve 4 on the gas inlet pipeline 2 for low-concentration gas, so that the concentration and flow rate of the gas in the pipeline entering the mixer 1 are increased, so that the concentration and flow rate of the mixed gas begin to increase and finally equal the target value; at the same time, the valve opening degree of the inlet control valve 4 on the gas inlet pipeline 3 for the gas to be mixed can also be reduced, so that the concentration and flow rate of the gas to be mixed in the pipeline entering the mixer 1 are reduced, and the concentration and flow rate of the mixed gas can also begin to increase and finally equal the target value. Through this automatic dynamic adjustment, the concentration and / or flow rate of the mixed gas are stabilized at the target value, making the pressure fluctuation of the mixed gas smaller and the volume fraction more stable, and meeting the usage requirements in the fields of gas utilization and chemical synthesis.

[0029] As Figure 1 shown, as a preferred embodiment of the present utility model, in order to ensure that the gas concentration and flow rate entering the mixer 1 meet the standards and accelerate the gas mixing process in the mixer 1, intake sensors are also provided on the gas intake pipeline 2 for gas with low calorific value and the gas intake pipeline 3 for the gas to be admixed, which are used to detect whether the concentration and flow rate of the gas in their respective pipelines entering the mixer 1 meet the standards; when the detection is qualified, the gas in the pipeline enters the mixer 1, and when the detection is unqualified, the gas in the pipeline is emptied, so as to shorten the time required for the concentration and flow rate of the admixed gas to reach the target value preset by the system, and thus improve the work efficiency.

[0030] As Figure 1 shown, as a preferred embodiment of the present utility model, on-off valves 5 are also provided on the gas intake pipeline 2 for gas with low calorific value and the gas intake pipeline 3 for the gas to be admixed. The on-off valves 5 are signal-connected to the controller. The controller controls the opening and closing of the valves of the on-off valves 5 to communicate with and cut off the mixer 1, and controls the valves of the on-off valves 5 to open to allow the gas to enter the mixer 1 when the gas concentration and flow rate in the pipeline meet the standards, and controls the valves of the on-off valves 5 to close to empty the gas when the gas concentration and flow rate in the pipeline do not meet the standards.

[0031] In the embodiment of the present utility model, the on-off valve 5 is used to control the gas in the pipeline to enter the mixer, and the intake regulating valve 4 is used to control the flow rate of the gas in the pipeline entering the mixer 1. In the initial state, the on-off valve 5 and the intake regulating valve 4 are in the closed state. When low-calorific-value gas and the gas to be admixed are respectively introduced, the intake sensors provided on the pipeline detect the flow rate and concentration of the gas in their respective pipelines in real time, and transmit the detection signals to the controller. The controller receives the detection signals and judges whether the gas concentration and flow rate entering the mixer 1 meet the standards. If they meet the standards, the controller controls the valves of the on-off valve 5 and the intake regulating valve 4 to open, and the gas in the pipeline enters the mixer 1; if they do not meet the standards, the on-off valve 5 and the intake regulating valve 4 continue to remain in the closed state, and the gas in the pipeline is emptied. At the same time, the gas in the pipeline after meeting the standards enters the mixer 1 for admixing. The sensor provided at the outlet end of the mixer 1 detects the concentration and / or flow rate of the admixed gas, and transmits the detection signal to the controller. After receiving the detection signal, the controller further judges whether the concentration and / or flow rate of the admixed gas conforms to the target value preset by the system. When it conforms, the valve opening of the intake regulating valve 4 remains unchanged; when it does not conform or fluctuates, the controller controls the valve opening of the intake regulating valve 4 to adjust the concentration and / or flow rate of the admixed gas by changing the gas flow rate entering the mixer 1, so that it is stabilized at the target value preset by the system.

[0032] As Figure 1As shown, in the embodiment of the utility model, an emptying pipeline 6 is also included, which is arranged on the gas inlet pipeline 2 and the gas inlet pipeline 3 to be mixed, respectively, and is used to discharge the gas whose concentration and flow rate in the gas inlet pipeline 2 and the gas inlet pipeline 3 do not meet the standards. The emptying pipeline 6 is provided with an emptying regulating valve 7, and the emptying regulating valve 7 is connected to the controller signal. The controller can control the valve opening and closing of the emptying regulating valve 7, and open the valve when emptying to allow the gas to be discharged through the emptying pipeline 6, and close the valve when not emptying. Among them, the emptying pipeline 6 is provided with a gas extraction multi-parameter sensor for real-time detection of the flow rate and pressure in the pipeline, and the gas outlet ends of each emptying pipeline 6 can be interconnected so that the gas in the pipeline converges to one pipeline for discharge.

[0033] As a preferred embodiment of the present invention, since the pneumatic control valve has low control accuracy but can respond quickly and can adapt well to the rapid opening and closing of the valve, the exhaust control valve 7 and the opening and closing valve 5 can be pneumatic control valves, and the electric control valve has high control accuracy and can more accurately adjust the gas flow in the pipe, so the air intake control valve 4 can be an electric control valve.

[0034] like Figure 1 As shown, as a preferred embodiment of the utility model, the exhaust pipe 6 is respectively located between the intake sensor and the intake regulating valve 4 on the gas intake pipe 2, and between the intake sensor and the intake regulating valve 4 on the mixed gas intake pipe 3. Based on this design, the sensor can be used in advance to detect whether the gas concentration and flow rate in the pipe meet the standards, so that the gas that meets the standards enters the mixer 1, and the gas that does not meet the standards enters the exhaust pipe 4 for exhaust.

[0035] In the embodiment of the present utility model, Figure 1 As shown, the inlet of the gas intake pipeline 3 to be mixed is connected to a second air duct 17, and the inlet of the second air duct 17 is provided with a second fan 18 for inputting air into the second air duct 17, and a second air intake manual valve 21 is provided on the second air duct 17. The inlet of the gas intake pipeline 2 is connected to a first air duct 15, and the gas intake pipeline 2 is connected to the gas source 12 through a gas intake manual valve 13, and the inlet of the first air duct 15 is provided with a first fan 16 for inputting air into the first air duct 15, and a first air intake manual valve 20 is provided on the first air duct 15.

[0036] As a preferred embodiment of the present invention, Figure 1As shown in the figure, one end of the exhaust air main pipe 14 is connected to the gas source 12 through the exhaust air inlet valve 19, and the other end is connected to the second air pipe 17 between the second air inlet manual valve 21 and the gas inlet pipe 3 to be blended. Among them, the exhaust air inlet valve 19 can be an electric regulating valve. When the exhaust air inlet valve 19 opens the valve, the gas source 12 is connected to the exhaust air main pipe 14, and the exhaust air enters the gas inlet pipe 3 to be blended through the exhaust air main pipe 14. The valve of the second air inlet manual valve 21 is closed, and the gas inlet pipe 3 to be blended is used as an exhaust air pipe. At this time, the device is used for the blending of low-concentration gas and exhaust air. When the exhaust air inlet valve 19 closes the valve, the gas source 12 is disconnected from the exhaust air main pipe 14, and the valve of the second air inlet manual valve 21 is opened. The gas inlet pipe 3 to be blended is used as an air pipe. At this time, the device is used for the blending of low-concentration gas and air.

[0037] In the embodiment of the present utility model, the outlet sensor includes a gas drainage multi-parameter sensor 8 and a laser methane sensor 9. The inlet sensor also includes a gas drainage multi-parameter sensor 8 and a laser methane sensor 9. The gas drainage multi-parameter sensor 8 is used to detect the gas flow rate and pressure in the pipe in real time, and the laser methane sensor 9 is used to detect the methane concentration of the gas in the pipe in real time.

[0038] As Figure 1 shown, as a preferred embodiment of the present utility model, flame arresters 10 are provided on the gas inlet pipe 2 and the gas inlet pipe 3 to be blended, which are used to improve the safety of the gas transported in the pipe, prevent backfire from occurring, and ensure the safety of equipment and personnel.

[0039] As Figure 1 shown, in the embodiment of the present utility model, the low-concentration gas mixing system further includes a mixed gas outlet pipe 11, which is connected to the outlet end of the mixer 1 and is used to output the gas after the low-concentration gas and the gas to be blended in the mixer 1 are blended. The outlet sensor at the outlet end of the mixer 1 can be arranged on the outlet pipe 11. According to the detected gas concentration and / or flow rate in the pipe, the concentration and / or flow rate of the blended gas can be known, and according to the detected pressure value, the pressure value detected by the sensor on the gas inlet pipe 2, and the pressure value detected by the sensor on the gas inlet pipe 3 to be blended, the pressure loss of the blended gas can be obtained.

[0040] In the present utility model, a terminal display is further included. The terminal display is signal-connected to the controller and is used to display the detection data of each sensor and the preset target value, wherein the preset target value can be reset so that the concentration and / or flow rate of the blended gas is equal to the reset target value.

[0041] The working principle of this device is as follows:

[0042] By installing intake regulating valves 4 on the gas intake pipeline 2 and the gas to be blended intake pipeline 3 to regulate the flow rate, a multi-parameter gas drainage sensor 8 to measure the flow rate and pressure inside the pipeline in real time, and a laser methane sensor 9 to measure the concentration value of the gas in the pipeline in real time, all of their signals are connected to the PLC control cabinet, and are displayed and controlled through a PC computer. The valves are adjusted according to the readings of each sensor to make the flow rate and concentration of the gas or air meet the standards; when the flow rate and concentration of the gas or air do not meet the standards, only allow them to be discharged through their respective corresponding evacuation pipelines, and the qualified gas is introduced into the mixer 1. At this time, the evacuation pipeline 6 corresponding to the gas source is in a closed state, and the measured value by the laser methane sensor 9 set at the outlet end of the mixer 1 is used to reflect the blending effect of the mixer 1: uniformity and stability; the pressure loss of the mixer 1 is obtained from the pressure readings of the multi-parameter gas drainage sensors 8 set at the outlet end of the mixer 1 and on each intake pipeline.

[0043] When the gas source fluctuates, the system compares the collected methane concentration, flow rate with the target values preset in the system. When there is a deviation, the controller automatically adjusts the corresponding equipment according to the PID algorithm. The flow rate is adjusted by adjusting the intake regulating valve 4 connected to the gas source 12. When the methane concentration after blending is greater than the target value, the controller automatically reduces the opening degree of the intake regulating valve 4 at the front end of the mixer 1 on the gas intake pipeline 2, or automatically increases the opening degree of the intake regulating valve 4 at the front end of the mixer 1 on the gas to be blended intake pipeline 3, thereby reducing the gas flow rate entering the inside of the mixer 1 and then reducing the concentration; when the methane concentration after blending is less than the target value, the controller automatically increases the opening degree of the intake regulating valve 4 at the front end of the mixer 1 on the gas intake pipeline 2, or automatically reduces the opening degree of the intake regulating valve 4 at the front end of the mixer 1 on the gas to be blended intake pipeline 3, thereby increasing the gas flow rate entering the inside of the mixer 1 and then increasing the concentration. By adjusting the intake regulating valve 4, the methane concentration of the blended gas is stabilized at the target concentration, so that the volume fraction of the blended gas is more stable and the pressure fluctuation is smaller.

[0044] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A low-concentration gas mixing system, characterized in that: include: A mixer (1), wherein the mixer (1) is configured to have an inlet end for receiving gas input and an outlet end for outputting the gas after mixing; A gas inlet pipeline (2), which is connected to the inlet end of the mixer (1) and is used to input low-concentration gas into the mixer (1); An air inlet pipeline (3) for the gas to be mixed, which is connected to the air inlet end of the mixer (1) and is used to input the gas to be mixed into the mixer (1); Wherein, a gas outlet sensor is provided on the gas outlet end of the mixer (1) for detecting the gas concentration and / or flow rate of the low-concentration gas and the gas to be mixed in the mixer (1); The gas inlet pipeline (2) and the gas inlet pipeline (3) are provided with inlet regulating valves (4) for regulating the flow of the gas in the pipeline and the flow of the gas in the pipeline respectively. A controller is connected to the sensor and the air intake regulating valve (4) by signals, and the controller can control the valve opening of the air intake regulating valve (4) according to the detection signal transmitted by the sensor, thereby controlling the flow of the gas in the gas intake pipeline (2) and the gas to be mixed in the gas intake pipeline (3) entering the mixer (1), so that the concentration and / or flow of the mixed gas is stabilized at a target value preset by the system.

2. The low-concentration gas mixing system according to claim 1, characterized in that: The gas inlet pipe (2) and the mixed gas inlet pipe (3) are also provided with an inlet sensor for detecting whether the concentration and flow rate of the gas in the respective pipes entering the mixer (1) meet the standards; if the standards are met, the gas in the pipes enters the mixer (1); if the standards are not met, the gas in the pipes is discharged.

3. The low-concentration gas mixing system according to claim 2, characterized in that: The gas inlet pipeline (2) and the mixed gas inlet pipeline (3) are also provided with an on-off valve (5), the on-off valve (5) being connected to a controller signal, the controller being connected to and disconnected from the mixer (1) by controlling the opening and closing of the on-off valve (5), and controlling the on-off valve (5) to open when the gas concentration and flow rate in the pipe meet the standards so that the gas enters the mixer (1), and controlling the on-off valve (5) to close when the gas concentration and flow rate in the pipe do not meet the standards so that the gas is exhausted.

4. The low-concentration gas mixing system according to claim 3, characterized in that: The invention also comprises an exhaust pipe (6), which is arranged on the gas inlet pipe (2) and the gas inlet pipe (3) to be mixed, and is used to exhaust the gas whose concentration and flow rate do not meet the standards in the gas inlet pipe (2) and the gas inlet pipe (3) to be mixed, respectively. The exhaust pipe (6) is provided with an exhaust regulating valve (7), and the exhaust regulating valve (7) is connected to the controller signal. The controller can control the opening and closing of the exhaust regulating valve (7), and open the valve when exhausting to allow the gas to be exhausted through the exhaust pipe (6), and close the valve when not exhausting.

5. The low-concentration gas mixing system according to claim 4, characterized in that: The exhaust regulating valve (7) and the opening and closing valve (5) are pneumatic regulating valves, and the air intake regulating valve (4) is an electric regulating valve.

6. The low-concentration gas mixing system according to claim 5, characterized in that: The exhaust pipe (6) is respectively located between the air intake sensor and the air intake regulating valve (4) on the gas intake pipe (2), and between the air intake sensor and the air intake regulating valve (4) on the gas intake pipe (3) to be mixed.

7. The low-concentration gas mixing system according to claim 6, characterized in that: The to-be-mixed gas inlet pipeline (3) is an air and / or lean air inlet pipeline.

8. The low-concentration gas mixing system according to any one of claims 2 to 7, characterized in that: The air intake sensor comprises a gas extraction multi-parameter sensor (8) and a laser methane sensor (9), and the gas outlet sensor comprises a gas extraction multi-parameter sensor (8) and a laser methane sensor (9). The gas extraction multi-parameter sensor (8) is used to detect the gas flow rate and pressure in the pipe in real time, and the laser methane sensor (9) is used to detect the gas concentration in the pipe in real time.

9. The low-concentration gas mixing system according to claim 8, characterized in that: The gas inlet pipeline (2) and the mixed gas inlet pipeline (3) are provided with flame arresters (10).

10. The low-concentration gas mixing system according to claim 9, characterized in that: The low-concentration gas mixing system further comprises a mixed gas outlet pipe (11), which is connected to the outlet end of the mixer (1) and is used to output the gas mixed with the low-concentration gas in the mixer (1) and the gas to be mixed.

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