Gas stabilizing device of low-concentration gas pressure swing adsorption concentration system

Abstract

The utility model discloses a gas stabilizing device of a low-concentration gas pressure swing adsorption concentration system. The gas stabilizing device comprises an SV type static mixer, a mixed gas methane concentration detector, a mixed gas buffer tank, a PLC concentration control assembly, a feed gas methane concentration detector, a feed gas flow controller and a return gas flow controller. Desorption gas obtained through the pressure swing adsorption and desorption process converges into an SV type static mixer in a gas mixing device through a return pipeline and is fully mixed with methane raw gas with fluctuating concentration in the mixer, linear modeling is carried out according to operation data, the expected concentration serves as an input value of a main controller, the actual concentration of the mixed gas serves as a feedback link, and the concentration of the mixed gas is calculated. The difference value of the two values is used as an input value of a backflow gas flow controller, the actual concentration of the mixed gas is influenced by controlling a set value of the backflow gas flow, and the effect of controlling the concentration of the mixed gas by regulating and controlling the backflow gas flow through the concentration of the mixed gas is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to low concentration methane separation technical field especially relates to a low concentration gas pressure swing adsorption concentration system's steady gas device. BACKGROUND

[0002] For a long time, low concentration gas can only be discharged into the atmosphere because it does not reach the standard of industrial utilization, which not only causes great resource waste, but also aggravates the greenhouse effect. It is a feasible way to utilize low concentration gas by using gas separation technology to enrich low concentration gas. For example, pressure swing adsorption (PSA) is a commonly used adsorption separation method. The operation of pressure swing adsorption is convenient. It only needs to adjust the pressure in the adsorption tower to complete the process of adsorption and desorption. The pressure swing adsorption process has low energy consumption, high efficiency, high automation degree and high product purity.

[0003] However, in order to obtain a concentrated product gas that can be directly applied by using pressure swing adsorption, the concentration of the gas raw material gas needs to reach at least the minimum value required by the selected methane adsorbent for the concentration of methane (for example, the minimum required value of the methane concentration in the gas raw material gas is 3.5% when using a certain methane adsorbent). When the minimum value is lower than this, the separation efficiency of the pressure swing adsorption device will be greatly reduced, which will seriously affect the economic efficiency of the device. According to the characteristics of coal mine gas extraction in actual production, in order to ensure safety, coal mines often configure gas extraction pumps with power far exceeding the set value, which results in that the methane concentration of the gas raw material gas extracted by the coal mine is often lower than the minimum methane concentration required for obtaining a usable product gas by pressure swing adsorption. In this case, even if the methane product obtained by pressure swing adsorption is still not effectively utilized, it is also not cost-effective. Therefore, most coal mine enterprises choose to directly discharge the gas without further utilization.

[0004] One possible way is to use high-concentration methane gas as a gas mixture with low-concentration gas to increase the methane concentration in the mixed gas, so as to meet the minimum feed requirement of the methane concentration of the raw material gas of the pressure swing adsorption device. However, if it is directly purchased from the market, it will obviously increase the operating cost of gas utilization of coal mine enterprises, and seriously reduce the economic efficiency of gas utilization. CONTENT OF THE UTILITY MODEL

[0005] Based on the above problems existing in the prior art, the utility model designs a low concentration gas pressure swing adsorption concentration system's steady gas device, so that without adding high concentration methane gas, the part of the methane-rich gas generated by pressure swing adsorption is used for gas mixing, so as to ensure that the methane concentration in the raw material gas entering the pressure swing adsorption system can meet the minimum value requirement of the methane concentration in the gas required by the methane adsorbent. In the steady gas device of the utility model, the term "steady gas" specifically refers to the process of converting low concentration gas into a raw material gas that meets the minimum concentration design value requirement of methane in the pressure swing adsorption system.

[0006] In order to achieve the above object, the utility model adopts the following technical scheme.

[0007] A kind of low-concentration gas pressure swing adsorption enrichment system's gas stabilizing device, including SV type static mixer, mixed gas methane concentration detector, mixed gas buffer tank, PLC concentration control component, gas methane concentration detector, gas flow controller and backflow gas flow controller;

[0008] One end of the SV type static mixer is connected to the gas inlet pipeline, and the gas inlet pipeline is provided with a gas methane concentration detector and a gas flow controller;

[0009] The other end of the SV type static mixer is connected to the mixed gas buffer tank through a mixed gas outlet pipeline, and the mixed gas buffer tank is provided with a mixed gas methane concentration detector;

[0010] The side wall of the SV type static mixer is provided with a backflow gas inlet pipeline, and the backflow gas is mixed with the low-concentration gas after entering the SV type static mixer through the backflow gas flow controller;

[0011] The PLC concentration control component is used to receive detection signals from the gas methane concentration detector and the mixed gas methane concentration detector, and to calculate the backflow gas flow adjustment signal based on the detection signal linear modeling, and to instruct the backflow gas flow controller to adjust the backflow gas flow, so as to obtain the raw gas that meets the methane minimum concentration design value requirement of the pressure swing adsorption enrichment system.

[0012] Preferably, the interior of the SV type static mixer is composed of a plurality of vertical SV type static mixer units and horizontal SV type static mixer units arranged alternately.

[0013] Preferably, the gas stabilizing device further comprises a fixed support, which can be made of any one of stainless steel material, wooden material or hard plastic. More preferably, the fixed support is surrounded by a frame component, and the bottom is a plate structure. Further preferably, the frame components and the plate structure can be detached. As a specific embodiment, the plate structure is a solid plate, or a plate with uniformly distributed hole structure, or a plate with a net structure. The design of the fixed support in the device can facilitate installation due to the detachable structure, and can also save materials by using frame structure and plate structure with uniformly distributed hole structure or plate with net structure.

[0014] Further preferably, universal wheels are installed at the bottom corners of the fixed support, so as to facilitate the movement of the device.

[0015] The beneficial effects of the utility model are as follows:

[0016] The utility model discloses a simple structure's low concentration gas pressure swing adsorption concentration system's steady gas device, through the special SV type static mixer of design, guarantee the methane analysis backflow part after concentration and gas fully mix, and through setting PLC concentration control component, monitor backflow gas and methane concentration in gas raw material gas, and according to the methane concentration signal linearity modeling that obtains in detection, calculate and obtain backflow gas flow regulation signal, and instruct backflow gas flow controller to adjust backflow gas flow, thereby obtain the raw material gas that satisfies the methane concentration minimum design value requirement of pressure swing adsorption concentration system, when the methane concentration in low concentration gas is too low, the pressure swing adsorption production device cannot steady operation, lead to the low methane product quality and cannot effectively utilize, and the device operation economy deteriorates the defect of difference. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the structural schematic diagram of the steady gas device of one embodiment of the utility model.

[0018] Figure 2 It is Figure 1 The internal structure diagram of SV type static mixer.

[0019] The sign: 1-SV type static mixer, 2-mixed gas methane concentration detector, 3-mixed gas buffer tank, 4-PLC concentration control component, 5-raw material gas methane concentration detector, 6-raw material gas flow controller, 7-backflow gas flow controller, a-gas inlet pipeline, b-backflow gas inlet pipeline, c-vertical SV type static mixer unit, d-horizontal SV type static mixer unit, e-mixed gas outlet pipeline, f-raw material gas pipeline. DETAILED DESCRIPTION

[0020] In order to facilitate understanding the utility model, the utility model is described in detail below in conjunction with the drawings.

[0021] As Figure 1 The utility model discloses a low concentration gas pressure swing adsorption concentration system (PAS)'s steady gas device, including: SV type static mixer 1, mixed gas methane concentration detector 2, mixed gas buffer tank 3, PLC concentration control component 4, raw material gas methane concentration detector 5, raw material gas flow controller 6, backflow gas flow controller 7.

[0022] One end of the SV static mixer 1 is connected with a gas inlet pipeline, and the other end is connected with a mixed gas buffer tank 3 through a mixed gas outlet pipeline e, wherein: the gas inlet pipeline a is provided with a gas methane concentration detector 5 and a gas flow controller 6; the mixed gas buffer tank 3 is provided with a mixed gas methane concentration detector 2; and the side wall of the SV static mixer 1 is provided with a backflow gas inlet pipeline b, which is connected with a desorption gas pipeline of a pressure swing adsorption system.

[0023] The gas stabilizing device of the low-concentration gas pressure swing adsorption concentration system is provided with a special SV static mixer, so that the backflow gas and the raw material gas are fully mixed in the mixer.

[0024] As shown in Figure 2 The SV static mixer is composed of vertically arranged SV static mixer units c and horizontally arranged SV static mixer units d. The vertical and horizontal arrangement of the SV static mixer units can fully divide the gas flow in the mixer, continuously change the gas flow direction and rotation direction, and make the mixing more sufficient. Preferably, 5-7 groups of vertically and horizontally arranged static mixer units are arranged.

[0025] In the gas stabilizing device of the low-concentration gas pressure swing adsorption concentration system, the PLC concentration control assembly 4, the gas methane concentration detector 5, the mixed gas methane concentration detector 2 and the backflow gas flow controller 7 are connected through wires and jointly act on the mixed gas concentration control.

[0026] The gas stabilizing process of the gas stabilizing device of the low-concentration gas pressure swing adsorption concentration system is as follows:

[0027] (1) After the power is turned on and the PLC concentration control assembly 4 is initialized, the minimum methane concentration design value S0 of the PSA system raw material gas is input according to the methane concentration requirement of the raw material gas of the pressure swing adsorption concentration system;

[0028] (2) The gas methane concentration detector 5 and the mixed gas concentration detector 2 respectively collect the methane concentration in the feed gas and the methane concentration in the mixed gas in the mixed gas buffer tank, obtain the gas methane concentration measurement value C1 and the mixed gas methane concentration measurement value C2, and feed back to the PLC concentration control assembly 4;

[0029] (3) The PLC concentration control assembly 4 compares the gas methane concentration measurement value C1 with the minimum methane concentration design value S0 of the raw material gas:

[0030] a、When C1 < S0, it indicates that the raw gas needs to be refluxed and stabilized, and the PLC concentration control component 4 further compares the methane concentration C2 of the mixed gas with the minimum methane concentration design value S0 of the raw gas:

[0031] If C2 < S0, the PLC concentration control component 4 linearly models the real-time operation data according to the measured methane concentration C1 and the measured methane concentration C2 of the mixed gas, calculates the flow adjustment signal, and outputs the instruction to the reflux gas flow controller 7 to adjust the reflux gas flow to H1, and the reflux gas flow controller 7 increases the reflux gas flow; the cycle is repeated until the PLC concentration control component 4 receives the measured methane concentration C2' of the mixed gas ≥ S0, and the PLC concentration control component 4 instructs the reflux gas flow controller 7 to stabilize the reflux gas flow at the reflux gas flow value H2 corresponding to C2' ≥ S0;

[0032] b、When C1 ≥ S0, it indicates that the raw gas does not need to be refluxed and stabilized, and after the gas input device, the mixed gas is mixed through the mixed gas outlet pipeline e arranged on the SV type static mixer 1, and then sent into the PSA device for concentration treatment through the raw gas pipeline f from the mixed gas buffer tank 3.

[0033] c、When the measured methane concentration C1 of the gas is less than the minimum methane concentration design value S0 of the raw gas again, the above steps 2) and 3) are repeated until the raw gas meeting the operation of the PAS device is obtained.

[0034] 4) After replacing the adsorbent in the pressure swing adsorption device, a new minimum methane concentration design value S0' of the raw gas is input into the PLC concentration control component 4 according to the requirement of the replaced adsorbent, and the gas stabilizing device enters a new working cycle according to the same gas stabilizing process of the above steps 2) and 3).

[0035] The gas stabilizing device of the low-concentration gas pressure swing adsorption concentration system utilizes the real-time linear modeling of the operation data received by the PLC concentration control component 4 from the gas methane concentration detector 5 and the mixed gas methane concentration detector 2, calculates the flow adjustment signal, outputs the instruction to the reflux gas flow controller 7 to adjust the reflux gas flow, accurately controls the matching of the reflux gas and the methane concentration of the input gas, and is processed through reflux mixing, so that the methane gas concentration in the mixed gas input into the PAS methane enrichment system meets the design value requirement of the selected methane adsorbent in the PAS device for the minimum methane concentration in the raw gas, thereby ensuring the stability of the raw gas concentration in the pressure swing adsorption system, solving the technical problems that when the methane concentration in the low-concentration gas is too low, the pressure swing adsorption production device cannot be stably operated, the methane product quality is low and cannot be effectively utilized, and the economic efficiency of the device operation is poor.

[0036] In the process, the reflux gas is the methane desorption gas product with methane concentration greater than 8% after enrichment by the PAS device, and the methane desorption gas is mixed with the feed gas with methane concentration not more than 8% by controlling the amount of the methane desorption gas, so that the methane concentration in the mixed gas reaches the design value of the minimum methane concentration in the raw gas of the PAS device.

[0037] It should be noted that the drawings only show the preferred embodiments of the present application. The present application can also have many other different forms to realize, and is not limited to the embodiments described herein. The purpose of these embodiments of the present application is to make the disclosure of the present application more thorough and comprehensive, therefore, any skilled person in the art within the technical scope disclosed by the present application, according to the technical scheme and the inventive concept of the present application, equivalent replacement or change, should be covered within the protection scope of the present application.

Claims

1. A gas stabilization device for a low-concentration gas pressure swing adsorption (PSA) concentration system, characterized in that, It includes an SV-type static mixer (1), a mixed gas methane concentration detector (2), a mixed gas buffer tank (3), a PLC concentration control component (4), a gas methane concentration detector (5), a gas flow controller (6), and a return gas flow controller (7). One end of the SV-type static mixer (1) is connected to a gas inlet pipe (a), and a gas methane concentration detector (5) and a gas flow controller (6) are installed on the gas inlet pipe (a); the other end of the SV-type static mixer (1) is connected to a mixed gas buffer tank (3) through a mixed gas outlet pipe (e), and a mixed gas methane concentration detector (2) is installed on the mixed gas buffer tank (3); a return gas inlet pipe (b) is provided on the side wall of the SV-type static mixer (1), and the return gas enters the SV-type static mixer (1) through the return gas flow controller (7) and mixes with low-concentration gas; The PLC concentration control component (4) is used to receive detection signals from the gas methane concentration detector (5) and the mixed gas methane concentration detector (2), and to calculate the return gas flow rate adjustment signal based on the linear modeling of the detection signals, and to instruct the return gas flow rate controller (7) to adjust the return gas flow rate, thereby obtaining the raw material gas that meets the minimum methane concentration design value requirement of the pressure swing adsorption concentration system.

2. The gas stabilization device of the low-concentration gas pressure swing adsorption concentration system according to claim 1, characterized in that, The interior of the SV-type static mixer is composed of several sets of vertical SV-type static mixer units (c) and horizontal SV-type static mixer units (d) arranged alternately.

3. The gas stabilization device of the low-concentration gas pressure swing adsorption concentration system according to claim 2, characterized in that, The vertical SV static mixer unit (c) and the horizontal SV static mixer unit (d) are configured in 5-7 groups.

4. The gas stabilization device of the low-concentration gas pressure swing adsorption enrichment system according to any one of claims 1 to 3, characterized in that, It also includes a fixing bracket (8).

5. The gas stabilization device of the low-concentration gas pressure swing adsorption concentration system according to claim 4, characterized in that, The fixed bracket (8) is made of stainless steel, wood or hard plastic.

6. The gas stabilization device of the low-concentration gas pressure swing adsorption concentration system according to claim 5, characterized in that, The fixed bracket (8) has a frame component around its perimeter and a plate structure at the bottom.

7. The gas stabilization device of the low-concentration gas pressure swing adsorption concentration system according to claim 6, characterized in that, The plate structure is a solid plate, or a plate with uniformly distributed holes, or a plate with a mesh structure in plan.

8. The gas stabilization device of the low-concentration gas pressure swing adsorption concentration system according to claim 6, characterized in that, The frame components are detachable from each other, as well as from the frame components and the plate structure.

9. The gas stabilization device of the low-concentration gas pressure swing adsorption enrichment system according to any one of claims 6 to 8, characterized in that, The fixed bracket (8) is equipped with casters (9) at the four corners of its bottom.

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