CN103742122B - Underground Coal Gasification System and Gasification Method - Google Patents

Abstract

The invention provides a kind of underground coal gasification system and gasification process.Underground coal gasification system includes：First passage in coal seam, two ends are respectively communicated with venthole and via hole, and second channel, two ends are respectively communicated with via hole and directional hole, and combustion adjuvant is passed through by directional hole, and second channel forms reverse insertion area, gasifying agent is passed through by via hole, first passage forms positive gasification zone.It can make the underground coal gasification system and gasification process of reverse insertion process progress synchronous with positive gasification it is an object of the invention to provide a kind of.

Description

Underground Coal Gasification System and Gasification Method

technical field

The invention relates to the field of underground coal gasification, more specifically, to an underground coal gasification system and a gasification method.

Background technique

Underground coal gasification is a process in which coal in the ground is burned in a controlled manner, and combustible components are produced under thermal and physical and chemical effects, and transported to the ground. The wellless underground gasifier is formed by drilling holes from the ground to the coal seam, and directional drilling along the coal seam between the drill holes to open up gasification channels.

According to the different moving modes of the gasification working face, it can be divided into reverse penetration and forward gasification. Reverse penetration is to use air or low-concentration oxygen-enriched as a combustion aid, and send it to the fire area at a low speed through directional holes or coal seam cracks, so that the flame working surface moves in the direction opposite to the direction of the airflow, and mainly produces _CO2 and The process of evaporating water in the coal seam into water vapor is used to direct the expansion of horizontal pore channels. Forward gasification is to inject air or high-concentration oxygen-enriched gasification agent into the fire area at a high flow rate, so that the flame working surface moves in the same direction as the air flow direction, and forms oxidation zones, reduction zones, and carbonization under high-temperature combustion. Drying area, where the process is used for production.

The patent No. ZL200810119354.2 discloses a well-free gasification process, which introduces a method of expanding the gasification channel step by step by using auxiliary hole reverse combustion. Its disadvantages are as follows: firstly, the method of gasification after piercing is adopted, which leads to a long time for the gasifier to reach production; secondly, when a certain section is pierced, shrinkage cavities are likely to occur in other unpenetrated channels; thirdly, the water vapor generated during the piercing process cannot Being effectively utilized, the gasification efficiency is reduced.

Contents of the invention

In view of the problems existing in the related technologies, the object of the present invention is to provide an underground coal gasification system and a gasification method that can synchronize the reverse through process and the forward gasification process.

In order to achieve the above object, the present invention provides an underground coal gasification system, which includes: a first channel located in the coal seam, both ends of which are respectively connected to the air outlet and auxiliary holes, and a second channel, whose two ends are respectively connected to the auxiliary hole and the auxiliary hole The directional hole leads to the combustion aid through the directional hole, the second channel forms a reverse through area, the auxiliary hole leads to the gasification agent, and the first channel forms a forward gasification area.

Preferably, it also includes a combustion aid input device communicated with the directional hole, and a gasification agent input device communicated with the directional hole and the auxiliary hole.

Preferably, the combustion aid input device communicates with the first adjustment device, and the first adjustment device adjusts the volume flow and pressure of the combustion aid; and the gasification agent input device communicates with the second adjustment device, and the second adjustment device adjusts the volume flow and pressure of the gasification agent. pressure.

According to another aspect of the present invention, there is provided an underground coal gasification method, including: constructing air outlet holes, directional holes, auxiliary holes, a first channel connecting the air outlet holes and auxiliary holes, and a second channel connecting the auxiliary holes and directional holes ; The gasification agent is fed through the auxiliary hole to carry out forward gasification of the first passage, and at the same time, the combustion aid is passed through the directional hole to carry out reverse penetration of the second passage.

Preferably, after the construction is completed, it also includes: igniting at the place where the air outlet communicates with the first channel; feeding a combustion aid into the directional hole to reversely penetrate the first channel; The agent is used to gasify the first channel in the forward direction, and at the same time, the combustion aid is passed into the directional hole to penetrate the second channel in the reverse direction.

Preferably, when the concentration of carbon dioxide in the outlet gas at the auxiliary hole is greater than a first predetermined value, it is judged that the first passage is completed.

Preferably, after the forward gasification of the first channel is completed, the gasification agent is introduced through the directional holes to gasify the second channel.

Preferably, when the concentration of carbon dioxide at the directional hole is greater than a second predetermined value, it is judged that the positive gasification of the first channel ends.

Preferably, both the first predetermined value and the second predetermined value are 10%.

Preferably, the volume flow rate of the gasification agent is more than five times the volume flow rate of the combustion-supporting agent, and the pressure of the combustion-supporting agent is greater than the pressure of the gasification agent.

Preferably, the volume flow rate of the combustion aid is 600-1200 Nm ³ /h, and the volume flow rate of the gasification agent is 3000-8000 Nm ³ /h.

The beneficial technical effect of the present invention is that: through the technical solution of the present invention, the reverse through-through process and the forward gasification process can be carried out synchronously, shortening the time for the gasifier to reach production. At the same time, the combustion aid passes through the entire gasification channel, thus avoiding shrinkage cavities. In addition, since the water vapor and carbon dioxide produced in the reverse penetration process are directly delivered to the oxidation zone and reduction zone of the gasification production zone, it is beneficial to control the temperature of the oxidation zone and increase the effective components in the gas; more advantageously, the above water Steam and carbon dioxide are used in the oxidation zone and reduction zone, and also reduce the amount of sewage discharge, which is beneficial to environmental protection.

Description of drawings

Fig. 1 is a schematic diagram of an embodiment of the underground coal gasification system of the present invention.

detailed description

Fig. 1 shows a schematic diagram of an embodiment of the underground coal gasification system of the present invention. As shown in the figure, an underground coal gasification system is shown. The system includes a first channel 111 located in the coal seam 17, the two ends of the first channel 111 are respectively connected to the air outlet hole 12 and the auxiliary hole 11; and a second channel 112 is also included, and the two ends of the second channel 112 are respectively connected to the auxiliary hole 11 and the directional hole 10. The combustion oxidizer is fed through the directional hole 10, so that the second channel 112 forms a reverse through area; the gasification agent is fed through the auxiliary hole 11, so that the first channel 111 forms a forward gasification area.

The air outlet hole 12, the auxiliary hole 11 and the orientation hole 10 are arranged according to the positional relationship shown in FIG. 1 . Therefore, the first channel 111 and the second channel 112 are sequentially connected. The reverse through process and the forward gasification process are the same as those described in the background art. The flow direction of the combustion aid is from the orientation hole 10 to the air outlet hole 12 , and the movement direction through the flame working surface is from the air outlet hole 12 to the orientation hole 10 . In the forward gasification process, the flow direction of the gasification agent is from the auxiliary hole 11 to the gas outlet hole 12, or from the directional hole 10 to the auxiliary hole 11, and the moving direction of the working surface of the gasification flame is the same as the flow direction of the gasification agent.

Through the technical solution of the present invention, when the second channel 112 is reversely penetrated, the first channel 111 can be gasified in the forward direction at the same time. Since the reverse penetration process and the forward gasification process can occur at the same time, compared with the case where the channel is completely penetrated before gasification, the time to production can be shortened, that is, the entire process from the penetration process to production can be reduced. the time required. At the same time, since the combustion aid enters through the directional hole 10, it can flow through the second passage 112 and at the same time flow through the first passage 111, so compared with the situation of passing through the first passage 111 and then passing through the second passage 112, The possibility of shrinkage cavity in the orientation hole 10 can be reduced. In addition, since the carbon dioxide and water vapor produced during the passage of the second channel 112 need to flow out through the first channel 111, these carbon dioxide and water vapor can promote the positive progress of the gasification reaction, which will not only reduce the temperature to prevent the coal seam from overheating, It also increases the content of effective components in the gas due to the promotion of the forward reaction; in addition, because carbon dioxide and water vapor are used in the above-mentioned gasification process, it helps to reduce the discharge of sewage, which will promote environmental protection.

The air outlet 12 can be selectively communicated with the exhaust pipe or the gas production pipe, so as to discharge the exhaust gas in the penetration stage of the first channel 111, or discharge the gas produced in the gasification stage of the first channel 111 or the gasification stage of the second channel 112 of gas production. The auxiliary hole 11 can communicate with the gasification agent input device, so as to input the gasification agent during the gasification process of the first channel 111 . The directional hole 10 can be communicated with the combustion aid input device, so as to continuously provide the combustion aid for the whole penetration process. , supply gasification agent to the process through the directional hole 10 .

The first flow regulating valve 9 controls the amount of the gasification agent passing into the auxiliary hole 11, the second flow regulating valve 7 controls the amount of the combustion aid passing into the directional hole 10, and the third flow regulating valve 8 controls the amount of the combustion agent passing into the directional hole 10. The amount of gasifying agent. The second flow regulating valve 7 and the third flow regulating valve 8 are in an interlocking relationship. In this embodiment, both the gasification agent and the combustion aid are air A, which are respectively described as gasification agent and combustion aid for the purpose of brevity because they are respectively used in the gasification process and the penetration process. Those skilled in the art should understand that, in addition to air, the gasification agent and combustion aid can be other suitable gases, such as the combustion aid is an inert gas with low oxygen content, and the gasification agent is an inert gas with high oxygen content.

The gasification system may also comprise first adjustment means for the orientation hole 10 in communication with the oxidizer input means. The regulating device includes a fourth flow regulating valve 1 and a pressure regulator 2, which are respectively used to adjust the volume flow and pressure of the combustion aid. Similarly, the gasification system may also include a second regulating device for the auxiliary hole 11, communicated with the gasification agent input device, which includes a fifth flow regulating valve 3 and a pressure regulator 6, respectively used to adjust the gasification The volume flow and pressure of the agent. With the help of the above two adjustment devices (the first adjustment device and the second adjustment device), the volume flow ratio and pressure ratio of the gasification agent and the combustion oxidizer can be ensured to be appropriate. Preferably, the volume flow rate of the gasification agent is adjusted to be the The volume flow rate is at least 5 times, and the pressure of the combustion agent is adjusted to be greater than the pressure of the gasification agent, so as to realize the synchronization of the reverse through process and the forward gasification process. Preferably, the volume flow rate of the combustion aid is 600-1200 Nm ³ /h, and the volume flow rate of the gasification agent is 3000-8000 Nm ³ /h.

The gasification system may also include an oxygen supply. As shown in Figure 1, the oxygen supply device may include a sixth flow regulating valve 4 and a mixer 5, so that when the sixth flow regulating valve 4 is opened, an appropriate amount of oxygen is passed into the mixer 5, and the oxygen flow in the mixer 5 is mixed with the air flowing through the fifth flow regulating valve 3, and then the mixed gasification agent flows into the auxiliary hole 11 for the first channel gasification process. In addition, the oxygen-air mixture can also be used for the gasification process of the second channel through the third flow regulating valve 8 .

In addition, the coal gasification system may also include a sampling and detection device, which may be an air bladder or an infrared detection device commonly used in the art. During the passage of the first channel 111, the sampling and detection device can be used to detect the concentration of carbon dioxide in the outlet gas at the auxiliary hole 11. When the concentration exceeds the first predetermined value, the controller (valve) of the control device will make the auxiliary hole 11 11 communicates with the gasification agent input device, so as to input gasification agent into the auxiliary hole 11. When the detection result is equal to or lower than the first predetermined value, the working state before the detection is maintained. Similarly, the detection device can also be used to detect the gas in the directional hole 10 . Specifically, after the gasification of the first channel 111 is completed, the detection device detects the concentration of carbon dioxide in the gas at the directional hole 10, and when the concentration exceeds the second predetermined value, the control device closes the fourth flow regulating valve 1, the second The second flow regulating valve 7 , the first flow regulating valve 9 , and the third flow regulating valve 8 are opened to pass gasification agent into the directional hole 10 to gasify the second channel 112 . Similarly, when the detection result in the orientation hole 10 is equal to or lower than the second predetermined value, the working state before the detection is maintained. In this embodiment, both the first predetermined value and the second predetermined value are 10%.

The invention also provides a coal gasification method. An embodiment of the method includes: constructing the air outlet hole 12, the orientation hole 10 and the auxiliary hole 11, and constructing the first passage 111 connecting the air outlet hole 12 and the auxiliary hole 11 and the second passage 112 connecting the auxiliary hole 11 and the orientation hole 10 . Afterwards, the gasification agent is fed through the auxiliary hole 11 to gasify the first channel 111 in the forward direction, and at the same time, the combustion aid is fed through the directional hole 10 to make the second channel 112 reversely penetrated.

Through the above method, the reverse penetration process of the second channel 112 and the forward gasification process of the first channel 111 can be performed simultaneously, and other advantages mentioned above can be achieved. At the same time, the reverse penetration process and the forward gasification process are also as described above with reference to the underground coal gasification system. After the construction process of the above-mentioned channels and holes is completed, ignite at the connection between the air outlet hole 12 and the first channel 111, and input a combustion aid through the directional hole 10 to reversely penetrate the first channel 111, thereby forming an ignition column or ignition area 14 . Afterwards, open the gas outlet of auxiliary hole 11, the gas sampling detection in auxiliary hole 11, when the carbon dioxide concentration in this gas is greater than the first predetermined value, close the gas outlet of auxiliary hole 11, open the air inlet of auxiliary hole 11 , introduce the gasification agent into the auxiliary hole 11. The volume flow rate of the gasification agent is adjusted to be more than five times the volume flow rate of the combustion aid, and the pressure of the combustion aid is adjusted to be greater than the pressure of the gasification agent to ensure the forward gasification of the first channel 111 and the reverse direction of the second channel 112 Through synchronization. When the carbon dioxide concentration in the gas is less than or equal to the first predetermined value, the working state before detection is maintained. Similar to the above-mentioned detection method for the gas in the auxiliary hole 11, when the carbon dioxide concentration at the directional hole 10 is greater than the second predetermined value, it is judged that the positive gasification process of the first channel 111 is over, and at this time, the directional hole 10 leads into gasification agent, so as to gasify the second channel 112 . When the carbon dioxide concentration at the directional hole 10 is less than or equal to the second predetermined value, the working state before detection is maintained.

Specifically, the pressurized water control igniter is lowered through the air outlet hole 12 to ignite the coal seam 17, and the fourth flow regulating valve 1 and the second flow regulating valve 7 are opened to pass the combustion accelerant through the directional hole 10. When the coal seam burns to a certain When the width is large, the ignition column or ignition area 14 can be formed. As is well known to those skilled in the art, the aforementioned width can be calculated based on the amount of combustion accelerant introduced, the thickness of the coal seam, and the like. Adjust the flow rate of the combustion aid. In one embodiment, the volumetric flow rate can be adjusted to 600-1200 Nm ³ /h, and the pressure of the combustion aid can be adjusted through a pressure regulator. The pressure changes according to the length of the channel that needs to pass through.

Regularly open the air outlet of the auxiliary hole 11 to sample and analyze the auxiliary hole 11. When the concentration of carbon dioxide in the gas sample is greater than the first predetermined value, it means that the flame working surface of the through process has crossed the auxiliary hole 11. In this example, the first predetermined value is 10%. And when the flame working surface has crossed the auxiliary hole 11, the air outlet hole can be closed and the air inlet hole of the auxiliary hole 11 can be opened, so as to supply gasification agent in the auxiliary hole 11. And when the detection result is equal to or lower than the first predetermined value, the working state before the detection is maintained. Specifically, when the detected value is greater than 10%, the fifth flow regulating valve 3 and the first flow regulating valve 9 shown in FIG. 1 are opened, and the gasification agent is introduced through the auxiliary hole 11 . The fifth flow regulating valve 3 and the first flow regulating valve 9 are used to adjust the volume flow rate of the gasification agent. In one example, the volume flow rate can be adjusted to 3000-8000 Nm ³ /h, that is, to keep the flow rate in the auxiliary hole 11 The gas volume is more than 5 times of the intake air volume in the directional hole 10, so as to realize the positive gasification process of the gasification chamber between the auxiliary hole 11 and the gas outlet hole 12. At the same time, adjust the pressure of the combustion accelerant and gasification agent according to the degree of penetration and gasification, and keep the pressure of the combustion accelerant greater than the pressure of the gasification agent, so as to keep the reverse penetration and forward gasification at the same time. That is, the reactions in the gasification zone 15 and the reverse through fire zone 16 are kept synchronized.

In order to increase the effective components and calorific value in the gas, oxygen B can be added to the gasification agent. As shown in FIG. 1 , the sixth flow regulating valve 4 is opened, so that oxygen and air are mixed in the mixer 5 and then enter into the auxiliary hole 11 .

When the gasification reaction between the gas outlet hole and the auxiliary hole is over, the gas in the directional hole can be sampled and analyzed to determine whether the carbon dioxide concentration therein is greater than a second predetermined value. As is well known to those skilled in the art, the above reaction completion process can be calculated based on gas production, coal seam thickness, coal seam width, and the length of the second channel between the gas outlet hole and the auxiliary hole. When the above carbon dioxide concentration is greater than the second predetermined value, the fourth flow regulating valve 1 and the second flow regulating valve 7 are closed, and the third flow regulating valve 8 is opened, so that the gasification agent is passed into the directional hole, thereby improving the flow rate of the second channel. To gasify. Similarly, when the test result is equal to or less than 10%, maintain the working state before the test. In this example, the second predetermined value is 10%. As mentioned above, it is likewise possible to add oxygen to the gasification agent.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (12)

1. a kind of underground coal gasification system, including：First passage (111) in coal seam, two ends are respectively communicated with venthole (12) and via hole (11), and second channel (112), two ends are respectively communicated with via hole (11) and directional hole (10), its feature It is, be passed through combustion adjuvant by directional hole (10), the combustion adjuvant flows into the second channel (112), the second channel (112) Reverse insertion area is formed, while the combustion adjuvant also flows into the first passage (111), gasifying agent is passed through by via hole (11), The first passage (111) forms positive gasification zone.

2. underground coal gasification system according to claim 1, it is characterised in that also including connecting with the directional hole (10) Logical combustion adjuvant input unit, and the gasifying agent input unit connected with directional hole (10) and via hole (11).

3. underground coal gasification system according to claim 2, it is characterised in that the combustion adjuvant input unit connection the One adjusting means, first adjusting means adjusts the volume flow and pressure of the combustion adjuvant；And the gasifying agent input Device connects the second adjusting means, and second adjusting means adjusts the volume flow and pressure of the gasifying agent.

4. a kind of coal underground gasification method, it is characterised in that including：

Build the first of venthole (12), directional hole (10), via hole (11), the connection venthole (12) and via hole (11) The second channel (112) of passage (111), the connection via hole (11) and directional hole (10)；

Gasifying agent is passed through by via hole (11) positive gasification is carried out to the first passage (111), while logical by directional hole (10) Enter combustion adjuvant, the combustion adjuvant flows into second channel (112) to carry out reverse insertion to the second channel (112), while institute State combustion adjuvant and also flow into the first passage (111).

5. coal underground gasification method according to claim 4, it is characterised in that also include after the completion of structure：

Lighted a fire in the venthole (12) and the first passage (111) connectivity part；

Combustion adjuvant is passed through to the directional hole (10) reverse insertion is carried out to the first passage (111), when the first passage (111) after the completion of insertion, gasifying agent is passed through by via hole (11) positive gasification is carried out to the first passage (111), while to The directional hole (10) is passed through combustion adjuvant and carries out reverse insertion to second channel (112).

6. coal underground gasification method according to claim 5, it is characterised in that the outlet at the via hole (11) place In gas concentration lwevel be more than first predetermined value when, judge the first passage (111) insertion completion.

7. coal underground gasification method according to claim 6, it is characterised in that the first predetermined value is 10%.

8. coal underground gasification method according to claim 4, it is characterised in that when the first passage (111) is positive After gasification terminates, gasifying agent is passed through by the directional hole (10) second channel (112) is gasified.

9. coal underground gasification method according to claim 8, it is characterised in that in the directional hole (10) place titanium dioxide When concentration of carbon is more than second predetermined value, judge that the first passage (111) forward direction gasification terminates.

10. coal underground gasification method according to claim 9, it is characterised in that the second predetermined value is 10%.

11. coal underground gasification method according to claim 4, it is characterised in that the volume flow of gasifying agent is combustion-supporting More than five times of the volume flow of agent, combustion adjuvant pressure is more than gasifying agent pressure.

12. coal underground gasification method according to claim 11, it is characterised in that the volume flow of the combustion adjuvant is 600~1200Nm³/ h, the volume flow of the gasifying agent is 3000~8000Nm³/h。