CN103991955B - Dynamic monitoring method and dynamic monitoring device for gas generation in anaerobic digestion process - Google Patents

Abstract

The invention relates to a dynamic monitoring method and device for gas generation in an anaerobic digestion process. The device includes an anaerobic digestion system, a gas phase pressure range control unit, a valveless gas discharge unit, a gas discharge harmful component removal unit, and a gas discharge time point recording unit; the gas phase pressure range control unit includes a U-shaped Liquid pipe and liquid level controller; the gas phase part of the anaerobic digestion system is connected to one end of the U-shaped liquid pipe and the valveless gas discharge unit through a corrosion-resistant hose; the other end of the U-shaped liquid pipe is connected to the liquid level through a wire. The liquid level controller is connected to the valveless gas discharge unit and the gas discharge time point recording unit respectively through wires; connected to the sub-removal unit. The method and device of the invention are applied to the dynamic monitoring of gas production in an anaerobic digestion system, and are suitable for the dynamic monitoring research of gas production in indoor and outdoor anaerobic digestion processes.

Description

A dynamic monitoring method and device for gas production during anaerobic digestion

technical field

The invention relates to anaerobic treatment process monitoring, in particular to a dynamic monitoring method and device for gas generation in anaerobic digestion process.

Background technique

In the research of anaerobic digestion process, the determination of gas production in anaerobic digestion system generally adopts the drainage method. The principle of this method is to fill the air chamber with water first, and discharge an equal volume of water when the gas is generated into the air chamber. The gas volume is thus determined. For a small-scale anaerobic digestion system, the total gas production is not large, and a larger gas chamber can be used to collect all the gas at one time. At this time, it is more convenient and simple to use the drainage method. However, for a large-scale anaerobic digestion system, due to the large amount of gas production, if the drainage method is used to monitor the gas production, either a large gas chamber is used to collect all the gas at one time; gas. Among them, the method of using a large gas chamber is generally not feasible in laboratory research, and the use of conventional gas chamber collection requires experimenters to discharge the gas inside the gas chamber in a timely manner, which consumes a lot of time and energy for maintenance. Another disadvantage of the drainage method is that the gas collected by this method is generally low-soluble methane, hydrogen, etc., while carbon dioxide and hydrogen sulfide with high solubility will pass through passive diffusion and active drainage during the gas collection process. A large degree of loss not only pollutes the indoor environment, but also can only approximately reflect the total amount of anaerobic gas produced, and it is not easy to reflect the dynamic change of anaerobic gas emission rate.

The gas production of the anaerobic digestion system is characterized by a relatively low gas production rate and large fluctuations. The measurement ranges of various gas flowmeters currently on the market are often higher than the gas production rate of the general anaerobic process, and the required The working pressure is relatively high, and it is generally suitable for the measurement of gas flow rates such as natural gas, coal gas, and liquefied petroleum gas in industrial production environments. It is not suitable for the monitoring of anaerobic digestion systems with relatively small and variable gas production rates.

Contents of the invention

In order to overcome the deficiencies of the existing drainage methods, the purpose of the present invention is to provide a dynamic monitoring method and device for gas production in an anaerobic digestion process.

To achieve the above object, the technical solution adopted in the present invention is:

A dynamic monitoring device for gas production during anaerobic digestion, characterized in that it includes an anaerobic digestion system, a gas phase pressure change range control unit, a valveless gas discharge unit, a harmful component removal unit for the discharge gas, and a gas Emission time point recording unit;

The gas phase pressure change range control unit includes a U-shaped liquid pipe and a liquid level controller; the gas phase part of the anaerobic digestion system is respectively connected to one end of the U-shaped liquid pipe and the valveless gas discharge unit through a corrosion-resistant hose;

The other end of the U-shaped liquid pipe is connected to a liquid level controller through a wire, and the liquid level controller is respectively connected to a valveless gas discharge unit and a gas discharge time point recording unit through a wire; It is connected to the harmful component removal unit of the exhaust gas through a corrosion-resistant hose.

One end of the U-shaped liquid pipe communicates with the gas phase of the anaerobic digestion system through a corrosion-resistant hose, and the other end is equipped with a hanging conductive probe connected to the liquid level controller through a wire.

The end of the U-shaped liquid pipe equipped with a suspended conductive probe is connected with a sealed air bag, and the U-shaped liquid pipe is equipped with 3 suspended conductive probes, and the three suspended conductive probes are suspended from the same level.

The three suspended conductive probes have height differences, wherein the relative heights of the suspended conductive probes at the two low points are the same.

The gas phase part of the anaerobic digestion system is connected to the container filled with water through a corrosion-resistant hose, and the hose is inserted below the water surface to passively discharge the gas generated by the anaerobic digestion system in the form of bubbles during an abnormal power failure.

The valveless gas exhaust unit is connected to the inverted triangular funnel provided on the harmful component removal unit of the exhaust gas through a corrosion-resistant hose; The copper sulfate solution of the gas harmful component removal unit is in contact with the liquid surface.

Using the dynamic monitoring method of the dynamic monitoring device for gas production in the anaerobic digestion process, during the anaerobic digestion process, the anaerobic digestion process is carried out in the anaerobic digestion system, the gas produced changes the gas phase pressure, and the increase and decrease of the gas phase pressure are respectively Push the gas phase pressure change range control unit. The liquid level at the normal pressure airtight end of the U-shaped liquid pipe rises and touches the hanging conductive probe at the high point, and the liquid level drops below the hanging conductive probe at the low point, and the signals are respectively transmitted to the valveless gas. The external discharge unit and the gas discharge time point recording unit realize the quantitative discharge and recording of the gas generated during the anaerobic digestion process, so as to realize the real-time and dynamic monitoring of the gas generation with a certain accuracy.

The valveless gas exhaust unit is connected to the inverted triangular funnel provided on the harmful component removal unit of the exhaust gas through a corrosion-resistant hose; The copper sulfate solution of the gas harmful component removal unit is in contact with the liquid surface. The concentration of the copper sulfate solution is 0.1-0.8N.

The advantage that the present invention has is:

1. The device of the present invention realizes the dynamic monitoring of the gas generation process of the anaerobic digestion system, greatly reducing the on-site maintenance requirements of the experimenters;

2. The device and method of the present invention can be suitable for dynamic monitoring of the anaerobic gas production process that changes in a large range, and the monitoring sensitivity can be adjusted according to the specific requirements of the experiment, and has a wide range of applications;

3. In the device of the present invention, the combined use of the valveless gas exhaust unit and the harmful component removal unit of the exhaust gas greatly reduces the impact of the harmful gas components produced by anaerobic digestion on the long-term operation of the monitoring equipment and the experimental laboratory. Adverse effects of the environment, suitable for indoor and outdoor anaerobic digestion process research.

4. The device of the present invention is suitable for dynamic monitoring of gas production in an anaerobic digestion system with variable gas production rate and long duration.

5. The present invention can not only measure the dynamic change of gas production in the anaerobic process, but also more accurately measure the total volume of anaerobic gas, and adopts a valveless gas exhaust unit and an exhaust gas harmful component removal unit, Effectively avoid the adverse effects of harmful gas components produced by anaerobic digestion on the monitoring device and laboratory environment, ensuring long-term operation.

Description of drawings

Fig. 1 is a diagram of a dynamic monitoring device for gas production in an anaerobic digestion system provided by an embodiment of the present invention.

Fig. 2 is the status of gas production in the anaerobic digestion system within 3 days in the embodiment of the present invention.

Fig. 3 is the status of gas production in the anaerobic digestion system within 10 days in the embodiment of the present invention.

Detailed ways

Example 1

The anaerobic digestion system 1 with a volume of 6.36L is equipped with anaerobic digestion activated sludge, the volume of the solution is 5.4L, and the easily degradable carbon source glucose is added, and the TOC load is 380mg/L, and the anaerobic digestion experiment is carried out. The anaerobic digestion system 1 is provided with two gas outlets, which communicate with one end of the U-shaped liquid pipe 6 and the valveless gas discharge unit 4 respectively through silicone tubes. The other end of the U-shaped liquid pipe 6 is equipped with three hanging conductive probes 9, wherein the relative heights of the probes at the two low points are the same; water is injected into the U-shaped liquid pipe 6 to close to the low point hanging conductive probes 9, and the U-shaped liquid One end of the pipe equipped with a suspended conductive probe 9 is connected to the sealed air bag 8 to form a closed environment at normal pressure, and the suspended conductive probe 9 is connected to the liquid level controller 7 through a wire 11 .

The vertical distance of the suspended conductive probe 9 at the high and low points in the U-shaped liquid pipe determines the sensitivity of monitoring and the exhaust volume each time. In this example, the distance between the suspended conductive probes at the high and low points was adjusted several times, and after several slow injections of nitrogen into the reactor for verification, the volume of each exhaust was finally determined to be 36 mL.

The valveless gas exhaust unit 3 is connected to the exhaust gas harmful component removal unit 4 through a silicone tube 10 .

The harmful component removal unit 5 of the exhaust gas is composed of an inverted triangular funnel and a container containing a 0.2N copper sulfate solution. The exhaust gas passes through the inverted triangular funnel and contacts the liquid surface of the 0.2N copper sulfate solution to remove hydrogen sulfide and other harmful components.

The gas discharge time point recording unit 4 converts the output signal of the anaerobic digestion system gas phase pressure change range control unit 2 into a switch, resistance, current or voltage change signal through a relay, and records it in real time through a switch/resistance/current/voltage recorder The start and stop time points of the gas emission of the anaerobic digestion system.

Under abnormal power failure conditions, after the gas generated in the anaerobic reaction system 1 reaches a certain pressure, the generated gas is passively discharged in the form of bubbles through the silicone tube 10 inserted at the bottom of the water-filled container 12 .

In this embodiment, the normal operation detection process of the device is as follows:

The gas generated in the anaerobic digestion system 1 continuously increases the gas phase pressure of the anaerobic digestion system 1, and through the silicone tube 10, pushes the liquid in the U-shaped liquid pipe 6 to move up to the airtight section at normal pressure. When the pendant probe 9 at the high point triggers the liquid level controller 7 to send the signal to the valveless gas discharge unit 4 and the gas discharge recording unit 5 through the wire 11, the switch of the valveless gas discharge unit 4 is activated to discharge the exhaust gas. Oxygen digests the gas in the reactor 1, and the recording unit 5 converts the exhaust signal into a switch opening signal through the relay, and records this moment as the start time point of the gas discharge.

The liquid level at one end of the U-shaped liquid pipe 6 is sealed at normal pressure and drops with the discharge of gas in the anaerobic digestion system. When the liquid level leaves the low point hanging probe 9, the liquid level sensor 7 sends a signal to the valveless gas again through the wire 11. The exhaust unit 4 makes it stop the exhaust, and the liquid level returns to the initial state. At the same time, the recording unit 5 converts the stop signal of the exhaust exhaust into the closing signal of the switch through the relay, and records this moment as the gas discharge. stop time point. Because the added carbon source is easily degradable glucose, the gas in the anaerobic digestion system 1 is generated rapidly, and a large amount of gas is generated within 1 day, and the gas generation in the anaerobic digestion system within 3 days is shown in Figure 2. Dynamic monitoring of gas production during anaerobic digestion.

Example 2

Embodiment 2 is basically the same with embodiment 1 operation process, and its difference mainly contains:

1. Add 2.5L of alkaline hydrolysis supernatant of residual activated sludge to the anaerobic digestion system, and the TOC concentration of the hydrolysis supernatant is 1.76g/L.

2. Shorten the distance between the high and low points in the U-shaped liquid tube, increase the monitoring sensitivity, and repeatedly inject nitrogen into the reactor for verification, and finally determine the volume of each exhaust to be 20mL.

The normal operation detection process of the device in this embodiment is the same as that in Embodiment 1. TOC from sludge alkaline hydrolyzate has high anaerobic degradability, especially the gas emission rate in the first 3 days is significantly higher than that in the next 7 days, and the gas emission rate in 10 days The status is shown in Figure 3, which realizes the dynamic monitoring of gas production in the anaerobic digestion process.

Claims (6)

1. A dynamic monitoring device for gas production in an anaerobic digestion process, characterized in that it comprises an anaerobic digestion system (1), a gas phase pressure variation range control unit (2), a valveless gas discharge unit (3), The harmful component removal unit (4) of the exhaust gas and the recording unit (5) of the time point of gas discharge; Among them, the gas phase pressure change range control unit (2) includes a U-shaped liquid pipe (6) and a liquid level controller (7); the gas phase part of the anaerobic digestion system (1) is respectively connected to the U-shaped liquid pipe ( 6) One end communicates with the valveless gas exhaust unit (3); The other end of the U-shaped liquid pipe (6) is connected to the liquid level controller (7) through a wire, and the liquid level controller (7) is respectively connected to the valveless gas discharge unit (3) and the gas discharge time point through a wire. The recording unit (5) is connected; the valveless gas exhaust unit (3) is connected to the exhaust gas harmful component removal unit (4) through a corrosion-resistant hose; One end of the U-shaped liquid pipe (6) communicates with the gas phase part of the anaerobic digestion system (1) through a corrosion-resistant hose (10), and the other end is equipped with a suspended conductive probe (9), and the suspended conductive probe (9) passes through Wire (11) is connected with liquid level controller (7); The end of the U-shaped liquid pipe (6) equipped with a suspended conductive probe (9) is connected with a sealed air bag (8), and the U-shaped liquid pipe (6) is equipped with 3 suspended conductive probes (9); The three hanging conductive probes (9) have height differences, wherein the relative heights of the hanging conductive probes at two low points are the same. 2. The dynamic monitoring device that gas produces in the anaerobic digestion process according to claim 1 is characterized in that: the gas phase part of the anaerobic digestion system (1) passes through a corrosion-resistant hose and a water-filled container (12) Connected, the hose is inserted below the water surface, and is used to passively discharge the gas generated by the anaerobic digestion system (1) in the form of bubbles during an abnormal power failure. 3. The dynamic monitoring device for gas production in the anaerobic digestion process according to claim 1, characterized in that: the valveless gas discharge unit (3) is connected with the harmful gas discharge unit (3) by a corrosion-resistant hose. The inverted triangular funnel on the component removal unit (4) is connected; the exhaust gas is in contact with the copper sulfate solution liquid surface of the harmful component removal unit (4) of the exhaust gas containing the copper sulfate solution through the inverted triangular funnel. 4. a dynamic monitoring method utilizing the dynamic monitoring device that gas is produced in the anaerobic digestion process as claimed in claim 1 is characterized in that: in the anaerobic digestion process, the anaerobic digestion process is carried out in the anaerobic digestion system, producing The gas changes the gas phase pressure, and the rise and fall of the gas phase pressure respectively push the liquid level of the normal pressure closed end of the U-shaped liquid pipe in the control unit to rise and contact the hanging conductive probe (9) at the high point, and the liquid level drops to Below the hanging conductive probe (9) at the low point, the signals are respectively transmitted to the valveless gas discharge unit (3) and the gas discharge time point recording unit (5), the distance between the high and low point hanging conductive probes is adjusted, and the Slowly inject nitrogen into the reactor every time for verification, and finally determine the volume of each exhaust, realize the quantitative discharge and record of the gas generated during the anaerobic digestion process, so as to realize real-time and dynamic monitoring of gas production with a certain accuracy. 5. the dynamic monitoring method of the dynamic monitoring device that utilizes gas to produce in the anaerobic digestion process according to claim 4, is characterized in that: described valveless type gas efflux unit (3) is arranged on by corrosion-resistant hose and The inverted triangular funnel on the exhaust gas harmful component removal unit (4) is connected; the outer exhaust gas passes through the inverted triangular funnel and the copper sulfate solution of the outer exhaust gas harmful component removal unit (4) filled with copper sulfate solution liquid surface contact. 6. The dynamic monitoring method of the dynamic monitoring device utilizing the gas generated in the anaerobic digestion process according to claim 5, characterized in that: the concentration of the copper sulfate solution is 0.1-0.8N.