KR101938759B1 - Automatic Control Method for Purification of Methane Target Concentration of Biogas by Measuring Real Time Methane Concentration - Google Patents

Abstract

The present invention relates to an automatic control method for purifying biogas in targeted even methane concentration by real-time measurement of methane concentration using two flow rate control units. The present invention relates to an automatic control method for purifying biogas at targeted even methane concentration by measuring methane concentration in real time using the two flow rate control units to supply fixed concentrations of methane when ion gas is upgraded and used for gas-to-liquid (GTL) reaction or hydrogen reforming, and specifically, to a gas purification method by different speeds of gas ingredients of a membrane. The automatic control method for purifying biogas can obtain purified gas of the methane in a preset concentration by increasing the predetermined flow rate and measuring the concentration of the purified gas. Two flow rate control devices are installed, and the preset targeted methane concentration can be reached in a moment when the measured methane concentration exceeds the targeted methane concentration over a predetermined level. The automatic control method also enables a method for reducing purity except for a method for increasing the purity of the methane. So, the automatic control method can automatically and fixedly purify the biogas to the preset target concentration.

Description

Technical Field [0001] The present invention relates to an automatic control method for purifying homogeneous methane homogeneous concentration of biogas by measuring a real time methane concentration using two flow controllers,

The present invention relates to an automatic control system for the purification of a target methane concentration of a biogas that can produce a certain purity of methane for use in various specific purposes in biogas ≪ / RTI >

Organic matter including organic wastes such as organic sludge and livestock manure are treated by techniques such as incineration, fermentation, and direct / indirect drying. However, in the case of incineration, harmful substances such as dioxins are generated, and a large amount of external energy is required, and the installation cost is high, which is not economical. In addition, there is a problem in that a considerable amount of energy is consumed to reduce 80% of water to 15% at the time of direct / indirect drying, and a bad odor is generated in the drying process and the solid fuel after drying. In addition, in the case of fermentation, the occurrence of such odor is particularly serious. However, energy efficiency is low, and it takes a long time and the waste water must be treated. In addition, marine sludge and livestock manure have been banned since January 2012 due to the effect of the Convention, and marine dumping is also prohibited for drinking wastewater generated during the treatment of food waste since January 2013. Accordingly, various technologies for producing biogas through such organic materials have been developed.

Biogas purification using conventional membranes is designed to purify more than a certain concentration due to gas separation due to the gas velocity difference of the membrane. When the concentration of the biogas is less than a certain concentration, it is recovered in the device to raise the target purity. And the like.

However, there is a method to raise the purity to a target purity at a low purity level, but there is no presentation or invented technique for the method of lowering the target purity level.

That is, when the biogas is solidified and used for specific purposes such as fuel cell, GTL (gas-to-liquid) reaction, hydrogen reforming, etc., the concentration of methane should be constantly supplied. If it is raised or lowered, the overall energy balance may change and cause problems in the subsequent process.

However, existing membrane purification methods can increase the purity, but when the purity is increased, there is no way to lower the purity, and a method of purifying the biogas at the time of automatic operation is urgently proposed In fact.

1. Korean Registered Patent No. 10-1697734 (Registered on December 12, 2017) "Biomethane purification system" 2. Korean Patent Publication No. 10-2015-0035290 (published on Apr. 20, 2014) " Method for producing biomethane using organic material " 3. Korean Patent Registration No. 10-1327338 (Registered on April 11, 2013) "System and Method for Biomethane Production and Carbon Dioxide Recovery"

It is an object of the present invention to provide a biogas purification system using a membrane, which is a technology for separating carbon dioxide from a biogas, and produces a certain methane purity The present invention is to provide an automatic control method for purifying homogeneous methane uniform concentration of biogas by measuring the real time methane concentration using two flow controllers which can be automatically refined within a range of 1% error in methane concentration.

Other objects and advantages of the present invention will be described hereinafter and will be understood by the embodiments of the present invention. Further, the objects and advantages of the present invention can be realized by the means and the combination shown in the claims.

SUMMARY OF THE INVENTION The present invention, as a means for solving the above problems,

A preset methane purification concentration value of the biogas to be purified is set (S10); A step S20 of supplying the biogas to be purified through the gas holder 10; A step (S30) in which the subject biogas is pretreated in the pretreatment unit (20); A step (S40) in which the pretreated biogas to be purified is compressed by the compression unit (30); A step (S50) in which the compressed biogas to be purified is gas-purified by a membrane filter as a gas purification unit 40; (S60) the concentration and components of the purified biogas are analyzed through the gas analysis unit 50; A step S70 of automatically adjusting the supply flow rate of the biogas to be purified through the gas flow rate controller so that the measured methane purification concentration value reaches the preset methane purification concentration value according to the analyzed concentration of the biogas; (S80) in which the produced biomethane is stored in the production storage unit 90; And a control unit.

As described above, the present invention enables biomethane production of a predetermined purity preset by a user, and is applicable to high-level processes based on energy balance beyond natural gas alternative fuels, contributing to biogas purification technology .

FIG. 1 is a conceptual diagram illustrating an automatic control method for purifying homogeneous methane uniform concentration of biogas by measuring the real time methane concentration using two flow controllers according to the present invention. FIG.
2 is an automatic control process diagram of one embodiment for purifying target methane concentration according to the present invention.
Figure 3 is a block diagram of an automatic control Graph showing the production gas component data according to the concentration-dependent flow rate control in the method according to an embodiment of the present invention.
FIG. 4 is a graph showing an operation data of an embodiment showing the flow rate control results of the first and second gas flow rate control units according to the present invention; FIG.

Before describing in detail several embodiments of the invention, it will be appreciated that the application is not limited to the details of construction and arrangement of components set forth in the following detailed description or illustrated in the drawings. The invention may be embodied and carried out in other embodiments and carried out in various ways. It should also be noted that the device or element orientation (e.g., "front,""back,""up,""down,""top,""bottom, Expressions and predicates used herein for terms such as "left,"" right, "" lateral, " and the like are used merely to simplify the description of the present invention, Or that the element has to have a particular orientation. Also, terms such as " first "and" second "are used herein for the purpose of the description and the appended claims, and are not intended to indicate or imply their relative importance or purpose.

The present invention has the following features in order to achieve the above object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

According to one embodiment of the present invention,

A preset methane purification concentration value of the biogas to be purified is set (S10); A step S20 of supplying the biogas to be purified through the gas holder 10; A step (S30) in which the subject biogas is pretreated in the pretreatment unit (20); A step (S40) in which the pretreated biogas to be purified is compressed by the compression unit (30); A step (S50) in which the compressed biogas to be purified is gas-purified by a membrane filter as a gas purification unit 40; (S60) the concentration and components of the purified biogas are analyzed through the gas analysis unit 50; A step S70 of automatically adjusting the supply flow rate of the biogas to be purified through the gas flow rate controller so that the measured methane purification concentration value reaches the preset methane purification concentration value according to the analyzed concentration of the biogas; (S80) in which the produced biomethane is stored in the production storage unit 90; And a control unit.

The gas flow rate control unit includes a shutoff valve 80 installed in the flow path between the first gas flow rate control unit 60 and the product storage unit 90 to turn ON / OFF the flow path of the biogas to be purified .

In step S70, when the measured methane purification concentration value is less than the predetermined minimum concentration value to the preset concentration value, the flow rate of the purified biogas flow amount flowing into the gas purification unit 40 through the first gas flow rate control unit 60 The methane purification concentration value of the first gas flow rate control unit 60 is further reduced (decreased) compared with the first case when the measured methane purification concentration value is less than the predetermined minimum concentration value And a second case in which all the refined gas is recovered through the second gas flow rate control unit 70 and bypassed to the gas holder 10 as an initial supply source.

If the measured methane purification concentration value is greater than the preset concentration value to the preset maximum concentration value, the flow rate of the biogas to be purified flowing into the gas purification section 40 through the first gas flow rate control section 60 is increased Methane refining concentration value and the flow rate of the purified gas is further increased through the second gas flow rate control unit 70 to bypass the gas holder 10 as the initial supply source, When the purified concentration value exceeds the predetermined maximum concentration value, the purified gas to be purified in the first gas flow rate control unit 60 is further increased and the purified gas is supplied through the second gas flow rate control unit 70 And bypassing the gas to the gas holder (10) as an original supply source.

Hereinafter, an automatic control method for purifying homogeneous methane uniform concentration of biogas by measuring the real time methane concentration using two flow controllers according to a preferred embodiment of the present invention will be described in detail with reference to FIG. 1 to FIG.

An automatic control method for purifying homogeneous methane uniform concentration of biogas by measuring the real time methane concentration using the two flow rate controllers according to the present invention is as follows.

Firstly, an apparatus for an automatic control method for purifying homogeneous methane uniform concentration of biogas by measuring the real time methane concentration using two flow controllers of the present invention will be described.

The gas holder 10, the pre-processing section 20, the compression section 30, the gas purification section 40, the gas analysis section 50, the first gas flow rate control section 60 (MFC-1) A control unit 70 (MFC-2), a shutoff valve 80, and a production storage unit 90.

The apparatuses described above are sequentially connected to each other, and the biogas that is initially introduced has the form in which the above-mentioned devices are sequentially passed through and purified and stored in the production storage unit 90.

1. Step (S10) in which a preset methane purification concentration value of the biogas to be purified is set:

The user can set a desired preset methane purification concentration value (set in the gas analysis unit 50 or a separate control unit) and measure the methane concentration of the biogas in real time through the gas analysis unit 50, The first and second gas flow rate control units 60 and 70 are selectively controlled so that the measured methane purification concentration value reaches the predetermined methane purification concentration value set forth above.

When the preset methane purification concentration value is thus set,

2. Step S20 in which the biogas to be purified is supplied through the gas holder 10,

3. Step (S30) in which the biogas to be purified is subjected to a pre-treatment operation (such as filtering) through the pre-treatment unit 20,

4. Step (S40) in which the pre-processed biogas to be purified is compressed through the compression unit 30 is progressed sequentially.

5. The method of claim 5, wherein the compressed biogas to be purified is gas-purified by a membrane filter (gas purification unit) 40 (S50). 6. The concentration and components of the purified biogas are analyzed Step S60:

The components and concentrations of the gas-purified crude gas (separated methane gas) are analyzed by the membrane filter of step S50 described above, and methane is produced as the predetermined methane purification concentration value preset by the user in step S10, The first and second gas flow rate control units 60 and 70 in step S70 to be described later selectively compare the methane purification concentration value to be stored in the controller 90 with the set methane purification concentration value, ), And the degree of opening / closing (opening / closing range).

Of course, the first and second gas flow rate control units 60 and 70 may be controlled through the gas analyzing unit 50 which proceeds to step S60 or the methane purification concentration value measured by the gas analyzing unit 50 may be separately The control section makes the control section compare the predetermined methane refining concentration value (desired methane concentration value desired by the user) to the control section of the first and second gas flow rate control sections 60 and 70 May be controlled.

The present invention relates to a gas purification method by a speed difference of a gas component of a membrane.

The main components of the biogas are methane and carbon dioxide, and carbon dioxide has a higher rate of movement than methane and permeates through the membranes of the membrane. Since the hollow fiber membranes are not sufficiently permeable to carbon dioxide when the gas velocity is high, the gas permeation rate of the gas should be controlled to maintain the proper concentration. Because the velocity is proportional to the flow rate, increasing the flow rate increases the concentration of carbon dioxide in the refinery gas. Also, since the velocity is proportional to the square root of the differential pressure at the same flow rate, the greater the differential pressure, the greater the concentration of carbon dioxide. When the temperature, pressure, concentration and flow rate of the biogas are constant, the change of the gas velocity due to the change of the downstream pressure can be predicted as the cause of the change of the purification performance in the automatic operation. When the pressure is increased at the rear end, the differential pressure is reduced and the methane concentration of the purifying gas is increased due to the decrease of the speed. In order to overcome this problem, in the present invention, a certain amount of flow rate is increased so as not to be influenced by the downstream pressure, as in the following step S70, so that a purified gas of a certain component can be obtained by controlling the speed of the purified gas.

7. In step S70, the supply flow rate of the biogas to be purified is automatically adjusted in real time through the gas flow controller so that the measured methane purification concentration value reaches the preset methane purification concentration value according to the analyzed biogas concentration ) And 8. step (S80) in which the produced biomethane is stored in the production storage unit 90:

 The step of controlling the gas flow rate control section (first and second gas flow rate control sections 60 and 70) according to the measured methane purification concentration value at step S60 described above so as to purify the biogas at the preset methane purification concentration value to be.

The flow rate can be adjusted at a certain concentration error, but if the flow rate exceeds the predetermined concentration of the target concentration, the flow rate can not be increased to the target value by the downstream pressure even if the flow rate in the pipe is increased through the first gas flow rate regulator 60. Therefore, the second gas flow rate regulator 70 is additionally provided so that piping that is not affected by the downstream pressure is installed, so that it can be instantaneously controlled to reach the gas purification purity.

That is, the flow rate of the first gas flow rate control unit 60 (MFC-1) is controlled according to the concentration of the biogas analyzed after setting the target methane refining concentration value of the biogas to be controlled according to the target methane concentration.

Referring to FIG. 1,

When the methane concentration through the gas purification section 40 through the gas analysis section 50 corresponds to a preset methane refining concentration value of 89 to 91% (target methane concentration value of the user), the first gas flow rate control section The controller 60 maintains the predetermined opening and closing degree at this time and opens the shutoff valve 80 to store the produced methane gas in the product storage unit 90. [ Thereafter, when the concentration changes after analyzing the gas through the gas analyzer 50 in real time, the following method is employed.

(1) When the methane concentration is 85 to 89%, the flow rate of the first gas flow rate controller (60) is decreased by 20% to decrease the flow rate. (When the measured methane refill concentration value is less than the preset minimum concentration value, 1 gas flow rate control unit 60 to decrease the flow rate of the biogas to be purified which flows into the gas purification unit 40, thereby increasing the methane purification concentration value)

(2) When the methane concentration is 85% or less, the flow rate of the first gas flow rate control unit 60 is reduced by 50%, the shutoff valve 80 is shut off, and the second gas flow rate control unit 70 is used to bypass the gas holder 10 Recall. (When the measured methane purification concentration value is less than the preset minimum concentration value, the flow rate of the biogas to be purified of the first gas flow rate control unit 60 is further reduced and the flow rate of the purified gas is reduced through the second gas flow rate control unit 70 The entire amount of gas is recovered and bypassed to the side of the gas holder 10 which is the original supply source)

(3) When the methane concentration is 91 to 95%, the flow rate of the first gas flow rate control unit 60 is increased by 20% to increase the flow rate, and the flow rate of the additional 20% is supplied through the second gas flow rate control unit 70 to the gas holder 10 ). (By increasing the flow rate of the biogas to be purified which flows into the gas purification section 40 through the first gas flow rate control section 60 when the measured methane purification concentration value exceeds the preset concentration value to the preset maximum concentration value, A third case in which the refined concentration value is decreased and the flow rate is increased and the further produced purified gas is recovered via the second gas flow rate control unit 70 by bypassing to the gas holder 10 side as the original supply source)

(4) At a methane concentration of 95% or more, the shutoff valve 80 is shut off, the flow rate of the first gas flow rate control unit 60 is increased by 50%, and the entire amount is bypassed to the gas holder 10 to be recovered. This is because the flow rate can be adjusted at a certain concentration error, but if the flow rate exceeds a certain level of the target concentration, the flow rate can not be increased to the target value by the downstream pressure. (When the measured methane purification concentration value exceeds the preset maximum concentration value, the second gas flow rate control unit 70 further increases the flow rate of the biogas to be purified in the first gas flow rate control unit 60, The entire amount of purified gas is recovered and bypassed to the side of the gas holder 10 as the original supply source)

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various changes and modifications may be made without departing from the scope of the appended claims.

10: gas holder 20: preprocessing section
30: compression section 40: gas purification section
50: gas analysis section 60: first gas flow rate control section
70: second gas flow rate controller 80: shutoff valve
90: Production storage

Claims (4)

In order to stabilize the biogas and to supply the concentration of methane uniformly in the fuel cell, GTL (gas-to-liquid) reaction or hydrogen reforming,
A preset methane purification concentration value of the biogas to be purified is set (S10);
A step S20 of supplying the biogas to be purified through the gas holder 10;
A step (S30) in which the subject biogas is pretreated in the pretreatment unit (20);
A step (S40) in which the pretreated biogas to be purified is compressed by the compression unit (30);
A step (S50) in which the compressed biogas to be purified is gas-purified by a membrane filter as a gas purification unit 40;
(S60) the concentration and components of the purified biogas are analyzed through the gas analysis unit 50;
A step S70 of automatically adjusting the supply flow rate of the biogas to be purified through the gas flow rate controller so that the measured methane purification concentration value reaches the preset methane purification concentration value according to the analyzed concentration of the biogas;
(S80) in which the produced biomethane is stored in the production storage unit 90,
The gas flow rate control unit is provided with a shutoff valve 80 installed in the flow path between the first gas flow rate control unit 60 and the production storage unit 90 to turn ON / OFF the flow path of the biogas to be purified,
In operation S70,
When the measured methane purification concentration value is less than the predetermined minimum concentration value to the preset concentration value, the flow rate of the biogas to be purified flowing into the gas purification section 40 through the first gas flow rate control section 60 is decreased, In a first case of increasing the value,
When the measured methane purification concentration value is less than the preset minimum concentration value, the purification gas to be purified in the first gas flow rate control unit 60 is further reduced and the purified gas is supplied through the second gas flow rate control unit 70, And bypasses the gas to the gas holder 10 as an initial supply source,
By increasing the flow rate of the biogas to be purified introduced into the gas purification unit 40 through the first gas flow rate control unit 60 when the measured methane purification concentration value is greater than the preset concentration value to the preset maximum concentration value, A third case in which the concentration value is decreased, the flow rate is increased, and the further produced purified gas is recovered by bypassing the purified gas through the second gas flow rate control unit 70 to the gas holder 10 as the initial supply source,
When the measured methane purification concentration value exceeds the preset maximum concentration value, the flow rate of the biogas to be purified in the first gas flow rate control unit 60 is further increased and the flow rate of the purified gas is increased through the second gas flow rate control unit 70 By the fourth case in which all the gas is recovered and bypassed to the gas holder 10 side as the original supply source,
And a control unit for controlling the flow rate of the methane gas, Way.
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