Stratified gas injection well and stratified gas injection method for domestic waste landfill

Abstract

The present invention relates to a layered gas injection well for a domestic waste landfill, which comprises a vertical sleeve provided with an air outlet in the sleeve part and a liftable gas injection head located in the vertical sleeve. The liftable gas injection head includes a sling, a central pipe connected to the lower end of the sling, an upper inflatable sealing capsule connected to the upper end of the central pipe, a lower inflatable sealing capsule connected to the lower end of the central pipe, an upper inflatable sealing capsule gas injection pipe, a lower inflatable sealing capsule gas injection pipe and a waste gas injection pipe. The vertical sleeve can extend from the stable degradation layer to the undegraded layer. The present invention also relates to a layered gas injection method for a domestic waste landfill. The first step is to excavate a gas injection well at a predetermined point in the domestic waste landfill to the stable degradation layer and lower the vertical sleeve into the gas injection well. The second step is to inject gas into the five waste layers. The present invention has the advantage that each waste layer can share the gas injection cavity for layered gas injection, and solves the problem of the excessively large range of the closed space existing in the existing layered gas injection with each gas injection cavity independently arranged.

Description

Technical Field

[0001] The present invention relates to the technical field of garbage treatment, and particularly to a layered gas injection well and a layered gas injection method for a domestic waste landfill. Background Art

[0002] With the development of the economic society and the improvement of people's living standards, the urban construction has been continuously expanding. The domestic waste landfill has changed from the edge of the city to the center or residential area of the city. The degradation rate of organic matter in the landfill waste is relatively slow in the anaerobic environment, and its stabilization period often requires 30 - 50 years. During this period, a large amount of leachate, foul smell and other harmful gases will be generated, thus posing a serious threat to the surrounding environment and exposed population. In view of the above problems, the aerobic ventilation gas injection well provides a new technical idea for the comprehensive improvement of the landfill.

[0003] A Chinese patent discloses an air injection device and an air injection system for a landfill (Publication No.: CN210230975U, Authorization Date: 20200403). The air injection well is longitudinally arranged in the landfill. A plurality of isolation layers are longitudinally arranged in the air injection well, so that the air injection well forms a plurality of air injection spaces distributed longitudinally and hermetically isolated. Each air injection space is provided with a filler. The air injection main pipe is connected to an air injection fan, and the air injection branch pipe is connected to the air injection main pipe. Under the control of a valve, gas is injected into the corresponding air injection space. However, through the detection and analysis of the landfill, it is found that the landfill includes five waste layers, which are, from top to bottom, an undegraded layer, a generally degraded layer, a moderately degraded layer, a highly degraded layer and a stably degraded layer. When injecting gas, different proportions of gas injection are carried out according to different layers in order to achieve the best garbage treatment effect. The above horizontal gas injection obviously cannot meet the requirements. For this reason, a Chinese patent discloses a layered gas injection well for in-situ aerobic stabilization of a landfill (Publication No.: CN 212190551U, Authorization Date: 20201222). The lower end of the well pipe of this gas injection well is sealed and the upper end is open, and it is connected to an external gas injection device through a wellhead device, and the lower end is sealed with a pipe cap; a longitudinal partition divides the inner cavity of the well pipe of the gas injection well into several gas injection channels; air outlet holes are arranged on the outer wall of the gas injection channels; several layered gas distribution devices are sequentially distributed on the outer wall of the well pipe of the gas injection well from top to bottom according to the corresponding target waste layers, and are sequentially connected to the well pipe of the gas injection well through the air outlet holes.

[0004] Although this gas injection well realizes layered gas injection, enabling the gas to be accurately injected into the corresponding waste layer, this technical solution sets up gas injection cavities corresponding to each waste layer one by one, which will result in an overly large sealed space range, and greatly reduce the gas injection efficiency and gas injection quality. Summary of the Invention

[0005] The present invention aims to provide a layered gas injection well and a layered gas injection method for a domestic waste landfill where each waste layer can share an air injection cavity for layered gas injection, solving the problem of too large a sealed space range existing in the independent setting of air injection cavities for the existing layered gas injection.

[0006] The above technical problems are solved by the following technical solutions: A layered gas injection well for a domestic waste landfill, the waste landfill includes five waste layers, and the five waste layers are, from top to bottom, an undegraded layer, a moderately degraded layer, a moderately degraded layer, a highly degraded layer, and a stably degraded layer. It is characterized in that it includes a vertical sleeve and a liftable gas injection head that can be lifted and lowered within the vertical sleeve. The wall of the vertical sleeve is provided with sleeve part air outlet holes. The liftable gas injection head includes a sling, a central pipe connected to the lower end of the sling, an upper inflatable sealing bag connected to the upper end of the central pipe, a lower inflatable sealing bag connected to the lower end of the central pipe, an upper inflatable sealing bag injection pipe for inflating the upper inflatable sealing bag and passing through the lower end of the central pipe, a lower inflatable sealing bag injection pipe for inflating the lower inflatable sealing bag, and a waste injection pipe for inflating the injection cavity separated by the upper and lower inflatable sealing bags and the central pipe within the vertical sleeve. The vertical sleeve can extend from the stably degraded layer to the undegraded layer. When in use, after aligning the liftable gas injection head with the corresponding waste layer by moving it up and down, then inflating to make the inflatable sealing bag sealed to form an injection cavity, and then injecting gas through the injection cavity. It not only realizes the layered gas injection with each waste layer sharing the injection cavity, but also reduces the sealed space range, improving the gas injection efficiency and gas injection quality.

[0007] Preferably, a gas distribution sleeve is sleeved on the central pipe. The gas distribution sleeve is located between the upper inflatable sealing bag and the lower inflatable sealing bag. The gas distribution sleeve and the central pipe enclose a gas distribution cavity. The gas distribution sleeve is provided with a plurality of gas distribution holes, and the gas distribution cavity is provided with a gas distribution sleeve part air inlet hole connected to the lower end of the output of the waste injection pipe. It can improve the uniformity when injecting gas into the waste layer.

[0008] Preferably, the gas distribution holes are covered with a blocking net that prevents waste from entering the gas distribution holes. It can prevent particulate matter from entering the sleeve part air outlet holes and causing blockage, affecting the gas injection effect.

[0009] Preferably, the vertical sleeve is provided with five air-permeable sections for aligning with the five waste layers one by one, and a plurality of air outlet holes of the sleeve parts are arranged on the air-permeable sections. The part of the vertical sleeve between adjacent air-permeable sections is a sealed section. An inner cylinder is rotatably connected to the air-permeable section, and inner cylinder air outlet holes are arranged on the inner cylinder. The inner cylinder can rotate to close all the air outlet holes of the sleeve parts. On the inner circumferential surface of the air-permeable section, a first fixed seal block, a second fixed seal block, a first limit block, a second limit block, an upper isolation ring and a lower isolation ring extending along the circumferential direction of the air-permeable section are hermetically and fixedly connected. On the outer circumferential surface of the inner cylinder, a first movable seal block and a second movable seal block are hermetically and fixedly connected. The air-permeable section, the first fixed seal block, the upper isolation ring, the lower isolation ring, the first movable seal block and the inner cylinder enclose a first sealed cavity. A first supporting block is fixedly connected to the inner circumferential surface of the inner cylinder, and a first vertical air inlet hole communicating with the first sealed cavity is arranged on the upper surface of the first supporting block. When gas is input into the first sealed cavity from the first vertical air inlet hole until the first movable seal block abuts against the first limit block, the inner cylinder closes all the air outlet holes of the sleeve parts. The air-permeable section, the second fixed seal block, the upper isolation ring, the lower isolation ring, the second movable seal block and the inner cylinder enclose a second sealed cavity. A second supporting block is fixedly connected to the inner circumferential surface of the inner cylinder, and a second vertical air inlet hole communicating with the second sealed cavity is arranged on the upper surface of the second supporting block. When gas is input into the second sealed cavity from the second vertical air inlet hole to drive the second movable seal block to rotate until it abuts against the second limit block, the gas output from the inner cylinder air outlet holes can be output through the air outlet holes of the sleeve parts. The first vertical air inlet hole and the second vertical air inlet hole are uniformly distributed along the circumferential direction of the inner cylinder. The air distribution sleeve is provided with air outlet nozzles and support heads that are uniformly distributed along the circumferential direction of the air distribution sleeve. When the air outlet nozzle is inserted into one of the second vertical air inlet hole and the first vertical air inlet hole, and the support head is inserted into the other one, an air outlet ring groove is rotatably sleeved on the central tube, and the air outlet ring groove is communicated with the air outlet nozzle through a connecting pipe. The central tube is provided with an inner cylinder rotating air injection pipe with the lower end communicated with the air outlet ring groove. When the air outlet nozzle is inserted into the first vertical air inlet hole, it is communicated with the first sealed cavity, and when it is inserted into the second vertical air inlet hole, it is communicated with the second sealed cavity. When the support head is inserted into the first vertical air inlet hole, the first sealed cavity is communicated with the outside of the first sealed cavity through the first vertical air inlet hole, and when it is inserted into the second vertical air inlet hole, the second sealed cavity is communicated with the outside of the first sealed cavity through the second vertical air inlet hole. The first supporting blocks on all the inner cylinders are staggered with each other along the circumferential direction of the vertical sleeve. It is possible to close and open the air outlet holes of the sleeve parts without setting electrical components in the vertical sleeve, so that leakage can be prevented after the waste layer is inflated. No electrical components are used in the soil layer of the landfill, and the safety is good (it can prevent the explosion of electronic fires).

[0010] Preferably, five pairs of vertical positioning through grooves are provided on the sealing section and are circumferentially distributed along the vertical sleeve. The two vertical positioning through grooves in the same pair of vertical positioning through grooves are evenly distributed along the circumference of the vertical sleeve. The two vertical positioning through grooves in a pair of vertical positioning through grooves are aligned with the first vertical air inlet hole and the second vertical air inlet hole in the same inner cylinder in the up-and-down direction one by one. A vertical positioning slide bar of the pipe head is connected to the upper side of the pipe head. The vertical positioning slide bar of the pipe head can be simultaneously inserted into two adjacent vertical positioning through grooves up and down. A vertical positioning slide bar of the support head is connected to the upper side of the support head. The vertical positioning slide bar of the support head can be simultaneously inserted into two adjacent vertical positioning through grooves up and down. During use, the vertical positioning slide bar of the support head is inserted into the corresponding vertical positioning through groove and descends to accurately insert into the vertical air inlet hole that needs to be inserted, solving the problem that the cable lifting is prone to shaking and cannot be reliably aligned.

[0011] Preferably, the sleeve part air outlet hole is provided with an extension section protruding from the inner peripheral surface of the vertical sleeve. The extension section is hermetically abutted against the outer peripheral surface of the inner cylinder. The number of sleeve part air outlet holes is equal to the number of inner cylinder part air outlet holes and can be aligned with each other one by one. This can not only make the rotation labor-saving, but also make it convenient to open and seal the sleeve part air outlet hole.

[0012] Preferably, an outer turned edge is provided on the outer peripheral surface of the free end of the extension section. An outer annular blade of the sleeve part extending along the circumference of the extension section is formed between the circumferential surface of the outer turned edge and the end surface of the free end of the extension section. The outlet end of the inner cylinder part air outlet hole is provided with an inner turned edge of the inner cylinder part. An inner annular blade of the inner cylinder part extending along the circumference of the inner cylinder part air outlet hole is formed between the circumferential surface of the inner turned edge of the inner cylinder part and the outer peripheral surface of the inner cylinder. It can cut off the garbage and prevent the phenomenon of jamming and laborious rotation when the inner cylinder rotates.

[0013] Preferably, an inner turned edge of the sleeve part is provided on the inner peripheral surface of the free end of the extension section. An inner annular blade of the sleeve part extending along the circumference of the extension section is formed between the circumferential surface of the inner turned edge of the sleeve part and the end surface of the free end of the extension section. It can guide the garbage into the inner cylinder part air outlet hole and has a good anti-jamming effect.

[0014] A method for stratified gas injection in a domestic waste landfill, characterized in that: in the first step, an injection well is dug at a predetermined point in the domestic waste landfill to the stable degradation layer, and a vertical sleeve is lowered into the injection well; in the second step, gas injection is carried out for the five waste layers: the liftable gas injection head is lifted into the vertical sleeve by a sling to a position where the part of the central pipe between the upper and lower airtight sealing bags is aligned with the waste layer to be gas-injected. The upper airtight sealing bag is inflated through the upper airtight sealing bag injection pipe until it is sealed and abutted against the vertical sleeve, and the lower airtight sealing bag is inflated through the lower airtight sealing bag injection pipe until it is sealed and abutted against the vertical sleeve. The lower airtight sealing bag and the upper airtight sealing bag isolate a sealed area in the vertical sleeve. The sealed area is inflated through the waste injection pipe, and the gas in the other part of the sealed area is injected into the waste layer to be gas-injected through the air outlet holes of the sleeve part until it meets the requirements. After the gas injection of the waste layer to be gas-injected is completed, the lower airtight sealing bag and the upper airtight sealing bag are deflated and separated from the vertical sleeve, and then the liftable gas injection head is moved to the required position.

[0015] Preferably, in the initial state, the second limit block and the second dynamic seal block are abutted together, the air outlet holes of the sleeve part and the air outlet holes of the inner cylinder part are communicated, and during the gas injection process of the waste layer, the air outlet pipe head and the support head are respectively supported in the first vertical air inlet hole and the second vertical air inlet hole on the inner cylinder aligned with the waste layer to be gas-injected; in the second step, after the gas injection of the waste layer is completed and before the lower airtight sealing bag and the upper airtight sealing bag are deflated, the following air retention operation is carried out: the inner cylinder is inflated through the inner cylinder rotation injection pipe. As a result, the volume of the first sealed cavity increases and the volume of the second sealed cavity decreases, causing the inner cylinder to rotate. When the first dynamic seal block abuts against the first limit block, the inflation through the inner cylinder rotation injection pipe stops. At this time, the inner cylinder seals the air injection hole of the sleeve part, thereby realizing the maintenance after the gas injection of the waste layer. The gas discharged from the reduction of the volume of the second sealed cavity is discharged through the second vertical air inlet hole; when it is necessary to open the air outlet hole of the sleeve part, the following method is carried out: the air outlet pipe head and the support head are respectively supported in the second vertical air inlet hole and the first vertical air inlet hole on the inner cylinder that seals the air outlet hole of the sleeve part to be opened. The inner cylinder is inflated through the inner cylinder rotation injection pipe. As a result, the volume of the second sealed cavity increases and the volume of the first sealed cavity decreases, causing the inner cylinder to rotate. When the second dynamic seal block abuts against the second limit block, the inflation through the inner cylinder rotation injection pipe stops. At this time, the inner cylinder loses the sealing effect on the air injection hole of the sleeve part, and the gas discharged from the reduction of the volume of the first sealed cavity is discharged through the first vertical air inlet hole.

[0016] The present invention has the following advantages: each waste layer can share the gas injection cavity for stratified gas injection. When injecting gas, the range of the closed space to be formed is small, which can improve the gas injection efficiency and gas injection quality; after the gas injection is completed, it can be sealed to prevent air leakage and gas cross-flow through the gas injection mechanism. Description of the Drawings

[0017] Figure 1Schematic diagram of the usage state of the layered gas injection well in the domestic waste landfill;

[0018] Figure 2 Top view schematic diagram of the layered gas injection well in the domestic waste landfill;

[0019] Figure 3 For Figure 1 Partial enlarged schematic diagram at location A of

[0020] Figure 4 For Figure 3 Partial enlarged schematic diagram at location B of

[0021] Figure 5 For Figure 3 Partial enlarged schematic diagram at location C of

[0022] Figure 6 For Figure 3 D - D cross-sectional schematic diagram of

[0023] Figure 7 For Figure 6 Partial enlarged schematic diagram at location E of

[0024] Figure 8 For Figure 6 Partial enlarged schematic diagram at location F of

[0025] In the figure: garbage layer 1, undegraded layer 2, generally degraded layer 3, moderately degraded layer 4, highly degraded layer 5, stably degraded layer 6, vertical sleeve 7, sleeve part air outlet 8, sling 9, central pipe 10, upper inflatable seal bag 11, lower inflatable seal bag 49, upper inflatable seal bag injection pipe 12, lower inflatable seal bag injection pipe 13, injection cavity 14, garbage injection pipe 15, air distribution sleeve 16, air distribution cavity 17, air distribution hole 18, breathable section 19, sealed section 20, inner cylinder 21, inner cylinder part air outlet 22, extension section 23, outer annular blade of sleeve part 24, inner annular blade of sleeve part 25, inner cylinder part annular blade 26, first fixed seal block 27, second fixed seal block 28, first limit block 29, second limit block 30, upper isolation ring 31, lower isolation ring 32, first movable seal block 33, second movable seal block 34, first seal cavity 35, first supporting block 36, first vertical air inlet hole 37, second seal cavity 38, second supporting block 39, second vertical air inlet hole 40, gas outlet pipe head 41, support head 42, gas outlet ring groove 43, connecting pipe 44, inner cylinder rotating injection pipe 45, vertical positioning through groove 46, pipe head part vertical positioning slide bar 47, support head part vertical positioning slide bar 48, liftable gas injection head 50, gas injection well 51. Detailed implementation method

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] See Figures 1 to 8 , a layered gas injection well for a domestic waste landfill. The waste landfill includes five waste layers 1, which are, from top to bottom, an undegraded layer 2, a moderately degraded layer 3, a moderately degraded layer 4, a highly degraded layer 5, and a stably degraded layer 6. It includes a vertical sleeve 7 and a liftable gas injection head 50 that is lifted and lowered in the vertical sleeve through a sling 9. The wall of the vertical sleeve is provided with sleeve part air outlet holes 8. The liftable gas injection head includes a central pipe 10 connected to the lower end of the sling, an upper inflation sealing bag 11 connected to the upper end of the central pipe, a lower inflation sealing bag 49 connected to the lower end of the central pipe, an upper inflation sealing bag injection pipe 12 for inflating the upper inflation sealing bag and passing through the lower end of the central pipe, a lower inflation sealing bag injection pipe 13 for inflating the lower inflation sealing bag, and a waste injection pipe 15 for inflating the injection cavity 14 separated by the upper and lower inflation sealing bags and the central pipe in the vertical sleeve. The vertical sleeve can extend from the stably degraded layer to the undegraded layer. A gas distribution sleeve 16 is sleeved on the central pipe. The gas distribution sleeve is located between the upper inflation sealing bag and the lower inflation sealing bag. The gas distribution sleeve and the central pipe enclose a gas distribution cavity 17. The gas distribution sleeve is provided with a plurality of gas distribution holes 18. The gas distribution cavity is provided with a gas distribution sleeve part air inlet hole connected to the lower end of the output of the waste injection pipe, that is, the gas input by the waste injection pipe enters the gas distribution cavity and then is distributed and flows out. The gas distribution holes are covered with a blocking net that prevents waste from entering the gas distribution holes.

[0028] The method for layered gas injection into a domestic waste landfill through this layered gas injection is as follows: First step, dig a gas injection well 51 at a predetermined position in the domestic waste landfill to the stably degraded layer, and lower the vertical sleeve into the gas injection well; Second step, inject gas into the five waste layers: lift the liftable gas injection head into the vertical sleeve through the sling to a position where the part of the central pipe between the upper and lower airtight sealing bags is aligned with the waste layer to be injected with gas. Inflate the upper inflation sealing bag through the upper inflation sealing bag injection pipe to inflate and bulge it to be sealed against the vertical sleeve, and inflate the lower inflation sealing bag through the lower inflation sealing bag injection pipe to inflate and bulge it to be sealed against the vertical sleeve. The lower inflation sealing bag and the upper inflation sealing bag isolate a sealed area in the vertical sleeve. Inflate the sealed area through the waste injection pipe, and the rest of the sealed area is injected into the waste layer to be injected with gas through the sleeve part air outlet holes until it meets the requirements; after the injection of the waste layer to be injected with gas is completed, deflate the lower inflation sealing bag and the upper inflation sealing bag to disconnect from the vertical sleeve, and then move the liftable gas injection head to the required position.

[0029] Further, the vertical sleeve is provided with five ventilation sections 19 with a number of sleeve section air outlets for aligning with the five waste layers one by one. The part of the vertical sleeve between adjacent ventilation sections is a sealing section 20. An inner cylinder 21 is rotatably connected to the ventilation section, and the inner cylinder is provided with inner cylinder section air outlets 22. The inner cylinder can rotate to close all the sleeve section air outlets. The sleeve section air outlets are provided with an extension section 23 protruding from the inner peripheral surface of the vertical sleeve, and the extension section is sealingly abutted against the outer peripheral surface of the inner cylinder. The number of the sleeve section air outlets is equal to the number of the inner cylinder section air outlets and they can be aligned one by one. An outer turned edge is provided on the outer peripheral surface of the free end of the extension section, and an outer annular blade 24 of the sleeve section extending along the circumferential direction of the extension section is formed between the circumferential surface of the outer turned edge and the end surface of the free end of the extension section. An inner turned edge of the sleeve section is provided on the inner peripheral surface of the free end of the extension section, and an inner annular blade 25 of the sleeve section extending along the circumferential direction of the extension section is formed between the circumferential surface of the inner turned edge of the sleeve section and the end surface of the free end of the extension section. An inner turned edge of the inner cylinder section is provided at the outlet end of the inner cylinder section air outlet, and an inner annular blade 26 of the inner cylinder section extending along the circumferential direction of the inner cylinder section air outlet is formed between the circumferential surface of the inner turned edge of the inner cylinder section and the outer peripheral surface of the inner cylinder.On the inner circumferential surface of the air-permeable section, a first fixed seal block 27, a second fixed seal block 28, a first limiting block 29, a second limiting block 30, an upper isolation ring 31 and a lower isolation ring 32 extending along the circumferential direction of the air-permeable section are fixedly sealed. On the outer circumferential surface of the inner cylinder, a first movable seal block 33 and a second movable seal block 34 are fixedly sealed. The air-permeable section, the first fixed seal block, the upper isolation ring, the lower isolation ring, the first movable seal block and the inner cylinder enclose a first sealing cavity 35. On the inner circumferential surface of the inner cylinder, a first supporting block 36 is fixedly connected. On the upper surface of the first supporting block, a first vertical air inlet hole 37 communicating with the first sealing cavity is provided. When gas is input into the first sealing cavity from the first vertical air inlet hole until the first movable seal block abuts against the first limiting block, the inner cylinder closes all the sleeve part air outlet holes. The air-permeable section, the second fixed seal block, the upper isolation ring, the lower isolation ring, the second movable seal block and the inner cylinder enclose a second sealing cavity 38. On the inner circumferential surface of the inner cylinder, a second supporting block 39 is fixedly connected. On the upper surface of the second supporting block, a second vertical air inlet hole 40 communicating with the second sealing cavity is provided. When gas is input into the second sealing cavity from the second vertical air inlet hole to drive the second movable seal block to rotate until it abuts against the second limiting block, the gas output from the inner cylinder part air outlet holes can be output through the sleeve part air outlet holes (that is, the inner cylinder non-air outlet holes and the sleeve part outlet holes are aligned one by one). The first vertical air inlet hole and the second vertical air inlet hole are evenly distributed along the circumferential direction of the inner cylinder. On the air distribution sleeve, air outlet nozzles 41 and supporting heads 42 evenly distributed along the circumferential direction of the air distribution sleeve are provided. When the air outlet nozzle is inserted into one of the second vertical air inlet hole and the first vertical air inlet hole, the supporting head is inserted into the other one. An air outlet ring groove 43 is rotatably sleeved on the central tube. The air outlet ring groove is communicated with the air outlet nozzle through a connecting pipe 44. An inner cylinder rotating air injection pipe 45 with its lower end communicated with the air outlet ring groove is arranged through the central tube. When the air outlet nozzle is inserted into the first vertical air inlet hole, it is communicated with the first sealing cavity. When it is inserted into the second vertical air inlet hole, it is communicated with the second sealing cavity. When the supporting head is inserted into the first vertical air inlet hole, the first sealing cavity is communicated with the outside of the first sealing cavity through the first vertical air inlet hole. When it is inserted into the second vertical air inlet hole, the second sealing cavity is communicated with the outside of the first sealing cavity through the second vertical air inlet hole. The first supporting blocks on all the inner cylinders are staggered with each other along the circumferential direction of the vertical sleeve. In the initial state, the second limiting block and the second movable seal block abut against each other, and the sleeve part air outlet holes and the inner cylinder part air outlet holes are communicated. During the process of injecting gas into the garbage layer, the air outlet nozzle and the supporting head are respectively supported in the first vertical air inlet hole and the second vertical air inlet hole on the inner cylinder aligned with the garbage layer to be injected with gas.There are five pairs of vertical positioning through grooves 46 arranged circumferentially on the sealing section along the vertical sleeve. The two vertical positioning through grooves in the same pair of vertical positioning through grooves are evenly distributed along the circumferential direction of the vertical sleeve. The two vertical positioning through grooves in a pair of vertical positioning through grooves are aligned with the first vertical air inlet hole and the second vertical air inlet hole in the same inner cylinder in the up and down direction one by one. A vertical positioning slide bar 47 of the pipe head is connected to the upper side of the pipe head. The vertical positioning slide bar of the pipe head can be simultaneously inserted into two adjacent vertical positioning through grooves up and down. A vertical positioning slide bar 48 of the support head is connected to the upper side of the support head. The vertical positioning slide bar of the support head can be simultaneously inserted into two adjacent vertical positioning through grooves up and down. During use, the vertical positioning slide bar of the support head is inserted into the corresponding vertical positioning through groove and lowered to accurately insert into the vertical air inlet hole to be inserted, solving the problem that the cable lifting is prone to shaking and cannot be reliably positioned.

[0030] In the second step, after the gas injection into the garbage layer is completed and before deflating the lower inflatable seal bag and the upper inflatable seal bag, the following gas retention operation is carried out: Inflate through the inner cylinder rotating injection pipe. The result of inflation is that the volume of the first sealing cavity increases and the volume of the second sealing cavity decreases, causing the inner cylinder to rotate. Stop inflating through the inner cylinder rotating injection pipe when the first dynamic seal block abuts against the first limit block. At this time, the inner cylinder seals the sleeve part air injection hole, thus realizing the maintenance after gas injection into the garbage layer. The gas discharged from the reduction of the volume of the second sealing cavity is discharged through the second vertical air inlet hole. When it is necessary to open the sleeve part air outlet hole, the following method is carried out: Support the pipe head and the support head in the second vertical air inlet hole and the first vertical air inlet hole on the inner cylinder that seals the sleeve part air outlet hole to be opened respectively. Inflate through the inner cylinder rotating injection pipe. The result of inflation is that the volume of the second sealing cavity increases and the volume of the first sealing cavity decreases, causing the inner cylinder to rotate. Stop inflating through the inner cylinder rotating injection pipe when the second dynamic seal block abuts against the second limit block. At this time, the inner cylinder loses the sealing effect on the sleeve part air injection hole, and the gas discharged from the reduction of the volume of the first sealing cavity is discharged through the first vertical air inlet hole.

Claims

1. A layered gas injection well for a domestic waste landfill. The waste landfill includes five waste layers, which are, from top to bottom in sequence, an undegraded layer, a moderately degraded layer, a moderately degraded layer, a highly degraded layer, and a stably degraded layer. It is characterized in that, It includes a vertical sleeve and a liftable gas injection head that is lifted and lowered within the vertical sleeve by a sling. The wall of the vertical sleeve is provided with sleeve part air outlet holes. The liftable gas injection head includes a central tube connected to the lower end of the sling, an upper inflation sealing bladder connected to the upper end of the central tube, a lower inflation sealing bladder connected to the lower end of the central tube, an upper inflation sealing bladder injection tube for inflating the upper inflation sealing bladder with its lower end passing through the central tube, a lower inflation sealing bladder injection tube for inflating the lower inflation sealing bladder with its lower end passing through the central tube, and a waste injection tube for inflating the injection cavity separated by the upper inflation sealing bladder, the lower inflation sealing bladder and the central tube within the vertical sleeve. The vertical sleeve can extend from the stable degradation layer to the non-degraded layer. A gas distribution sleeve is sleeved on the central tube, and the gas distribution sleeve is located between the upper inflation sealing bladder and the lower inflation sealing bladder. The gas distribution sleeve and the central tube enclose a gas distribution cavity, and the gas distribution sleeve is provided with a number of gas distribution holes. The gas distribution cavity is provided with a gas distribution sleeve part air inlet hole connected to the lower end of the output of the waste injection tube. The vertical sleeve is provided with five breathable sections with a number of the sleeve part air outlet holes for aligning with the five waste layers one by one. The part of the vertical sleeve between adjacent breathable sections is a sealed section. An inner tube is rotatably connected to the breathable section, and the inner tube is provided with inner tube part air outlet holes. The inner tube can rotate to close all the sleeve part air outlet holes. On the inner peripheral surface of the breathable section, a first fixed sealing block, a second fixed sealing block, a first limiting block, a second limiting block, and upper and lower isolation rings extending along the circumferential direction of the breathable section are hermetically fixed. On the outer peripheral surface of the inner tube, a first movable sealing block and a second movable sealing block are hermetically fixed. The breathable section, the first fixed sealing block, the upper isolation ring, the lower isolation ring, the first movable sealing block and the inner tube enclose a first sealing cavity. A first supporting block is fixed on the inner peripheral surface of the inner tube, and a first vertical air inlet hole communicating with the first sealing cavity is provided on the upper surface of the first supporting block. When gas is input into the first sealing cavity from the first vertical air inlet hole to drive the first movable sealing block to abut against the first limiting block, the inner tube closes all the sleeve part air outlet holes. The breathable section, the second fixed sealing block, the upper isolation ring, the lower isolation ring, the second movable sealing block and the inner tube enclose a second sealing cavity. A second supporting block is fixed on the inner peripheral surface of the inner tube, and a second vertical air inlet hole communicating with the second sealing cavity is provided on the upper surface of the second supporting block. When gas is input into the second sealing cavity from the second vertical air inlet hole to drive the second movable sealing block to rotate and abut against the second limiting block, the gas output from the inner tube part air outlet holes can be output through the sleeve part air outlet holes. The first vertical air inlet hole and the second vertical air inlet hole are evenly distributed along the circumferential direction of the inner tube. The gas distribution sleeve is provided with air outlet pipe heads and support heads evenly distributed along the circumferential direction of the gas distribution sleeve. When the air outlet pipe head is inserted into one of the second vertical air inlet hole and the first vertical air inlet hole, the support head is inserted into the other one. An air outlet ring groove is rotatably sleeved on the central tube, and the air outlet ring groove is communicated with the air outlet pipe head through a connecting pipe. The central tube is provided with an inner tube rotation injection tube with its lower end communicated with the air outlet ring groove.When the air outlet pipe head is inserted into the first vertical air inlet hole, it is communicated with the first sealing cavity. When the air outlet pipe head is inserted into the second vertical air inlet hole, it is communicated with the second sealing cavity. When the support head is inserted into the first vertical air inlet hole, the first sealing cavity is communicated with the outside of the first sealing cavity through the first vertical air inlet hole. When the support head is inserted into the second vertical air inlet, the second sealing cavity is communicated with the outside of the second sealing cavity through the second vertical air inlet hole; the first supporting blocks on all the inner cylinders are staggered with each other along the circumferential direction of the vertical sleeve.

2. The layered gas injection well for a domestic waste landfill according to claim 1, characterized in that, The air distribution holes are covered with a blocking net that prevents garbage from entering the air distribution holes.

3. The layered gas injection well for a domestic waste landfill according to claim 1 or 2, characterized in that, On the sealing section, there are five pairs of vertical positioning through slots distributed circumferentially along the vertical sleeve. The two vertical positioning through slots in the same pair of vertical positioning through slots are evenly distributed along the circumferential direction of the vertical sleeve. The two vertical positioning through slots in a pair of vertical positioning through slots are correspondingly aligned with the first vertical air inlet hole and the second vertical air inlet hole in the same inner cylinder in the up and down direction. A vertical positioning slide bar of the pipe head is connected to the upper side of the pipe head. The vertical positioning slide bar of the pipe head can be simultaneously inserted into two adjacent vertical positioning through slots up and down. A vertical positioning slide bar of the support head is connected to the upper side of the support head. The vertical positioning slide bar of the support head can be simultaneously inserted into two adjacent vertical positioning through slots up and down.

4. The layered gas injection well for a domestic waste landfill according to claim 1 or 2, characterized in that, The air outlet holes of the sleeve part are provided with an extended section protruding from the inner peripheral surface of the vertical sleeve. The extended section is hermetically abutted against the outer peripheral surface of the inner cylinder. The number of the air outlet holes of the sleeve part is equal to the number of the air outlet holes of the inner cylinder part and can be correspondingly aligned one by one.

5. The layered gas injection well for a domestic waste landfill according to claim 4, characterized in that, On the outer peripheral surface of the free end of the extended section, there is an outwardly turned edge. Between the circumferential surface of the outwardly turned edge and the end surface of the free end of the extended section, there is an outer annular blade of the sleeve part extending along the circumferential direction of the extended section. At the outlet end of the air outlet hole of the inner cylinder part, there is an inwardly turned edge of the inner cylinder part. Between the circumferential surface of the inwardly turned edge of the inner cylinder part and the outer peripheral surface of the inner cylinder, there is an inner annular blade of the inner cylinder part extending along the circumferential direction of the air outlet hole of the inner cylinder part.

6. The layered gas injection well for a domestic waste landfill according to claim 5, characterized in that, On the inner peripheral surface of the free end of the extended section, there is an inwardly turned edge of the sleeve part. Between the circumferential surface of the inwardly turned edge of the sleeve part and the end surface of the free end of the extended section, there is an inner annular blade of the sleeve part extending along the circumferential direction of the extended section.

7. A method for layered gas injection in a domestic waste landfill applicable to a layered gas injection well of the domestic waste landfill according to any one of claims 1 to 6, characterized in that, Step 1: Excavate an air injection well to the stable degradation layer at a predetermined point in the domestic waste landfill, and lower the vertical sleeve into the air injection well. Step 2: Inject gas into the five waste layers: Lift the liftable gas injection head to the position in the vertical sleeve where the part of the central pipe between the upper and lower gas outlet sealing bags is aligned with the waste layer to be injected with gas through a sling. Inflate and bulge the upper inflation sealing bag through the upper inflation sealing bag injection pipe until it is sealed and abutted against the vertical sleeve, and inflate and bulge the lower inflation sealing bag through the lower inflation sealing bag injection pipe until it is sealed and abutted against the vertical sleeve. The lower inflation sealing bag and the upper inflation sealing bag isolate a sealed area in the vertical sleeve. Inflate the sealed area through the waste injection pipe, and the gas in the other part of the sealed area is injected into the waste layer to be injected through the air outlet holes of the sleeve part until it meets the requirements. After the gas injection of the waste layer to be injected is completed, deflate the lower inflation sealing bag and the upper inflation sealing bag to disconnect them from the vertical sleeve, and then move the liftable gas injection head to the required position. In the initial state, the second limit block and the second dynamic sealing block are abutted together, and the air outlet holes of the sleeve part and the air outlet holes of the inner cylinder part are connected. During the gas injection process of the waste layer, the gas outlet pipe head and the support head are respectively supported in the first vertical air inlet hole and the second vertical air inlet hole on the inner cylinder aligned with the waste layer to be injected with gas. In Step 2, after the gas injection of the waste layer is completed and before deflating the lower inflation sealing bag and the upper inflation sealing bag, perform the following gas retention operation: Inflate through the inner cylinder rotation injection pipe. As a result, the volume of the first sealing cavity increases and the volume of the second sealing cavity decreases, causing the inner cylinder to rotate. Stop inflating through the inner cylinder rotation injection pipe when the first dynamic sealing block abuts against the first limit block. At this time, the inner cylinder seals the inflation hole of the sleeve part, thus realizing the maintenance after the gas injection of the waste layer. The gas discharged from the reduction of the volume of the second sealing cavity is discharged through the second vertical air inlet hole. When it is necessary to open the air outlet hole of the sleeve part, perform the following method: Support the gas outlet pipe head and the support head in the second vertical air inlet hole and the first vertical air inlet hole on the inner cylinder that seals the air outlet hole of the sleeve part to be opened respectively. Inflate through the inner cylinder rotation injection pipe. As a result, the volume of the second sealing cavity increases and the volume of the first sealing cavity decreases, causing the inner cylinder to rotate. Stop inflating through the inner cylinder rotation injection pipe when the second dynamic sealing block abuts against the second limit block. At this time, the inner cylinder loses the sealing effect on the inflation hole of the sleeve part, and the gas discharged from the reduction of the volume of the first sealing cavity is discharged through the first vertical air inlet hole.

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