What Is Plombage?

The accumulation of debris often causes pipeline blockages and the potential for disaster. The debris floating in the gas flow will directly enter the gas pump through the pipeline, which not only shortens the gas pump maintenance cycle and service life, but also affects the gas utilization rate and the safety of the pumping station.

Problems with existing debris processing technology

(1) The intermittent water dispenser cannot meet the requirement of large water volume. The currently used artificial water dispensers and negative pressure automatic water dispensers are both intermittent water dispensers. The intermittent water drainer has the disadvantages that it does not release water when storing water, and does not store water when discharging water. Once the water dispenser starts to drain water, its inlet pipe starts to store water. Once the air intake pipe is filled with water, the water in the pipe will continue to increase or flow downstream. The water will gradually accumulate in the pipe until the water dispenser has finished refilling the water. cut back. Therefore, when the intermittent water dispenser is applied in a place with abundant water sources and a large amount of incoming water, there may be more and more accumulated water or it will flow downstream to form a new accumulation point. The water in the lower part of the pipeline will either flow downstream or accumulate more and more, which will eventually block the pipeline.

(2) The atomized small water particles and the water not flowing into the drain will flow downstream and form a new water accumulation point. In some gas extraction pipelines with high gas velocity, the atomized small water particles will not only flow downstream, but also be pumped to the gas pumping station. At present, not only the small water particles that are atomized will flow downstream, as long as the water flowing along the bottom of the pipeline has a high flow velocity, under the action of inertia, some of the water will also flow downstream, forming new water accumulation points.

(3) Lack of special measures and techniques for removing debris in pipelines. Because the debris in the pipeline is not as direct and obvious as the effect of standing water on gas drainage, people only release part of the debris by discharging water. Some debris with large density and particles will stay in the pipeline and gradually increase, increasing pipeline resistance, and even blocking the pipeline; debris floating in the gas stream will directly enter the gas pump through the pipeline, not only shortening the gas pump maintenance Cycle and service life also affect gas utilization and pump station safety. Debris that enters the water dispenser with water can be released with the water, but once the speed of these debris has passed through the automatic water dispenser inlet and outlet, the small debris will easily adhere to the valve seat or valve cover, which will cause the The drain valve is not closed tightly, so that the drainer cannot normally store or drain water.

Water accumulation and debris treatment methods in debris pipeline

1. Analysis of water and debris sources

(1) The source of water. The Hebi mining area is a single coal seam, and there are sandstone aquifers on the top and bottom of the coal seam. Affected by mining, the water in the top and bottom aquifers will enter the non-aquifers and coal seams of the top and bottom of the coal seam through cracks. Whenever a hole is drilled into these coal rock formations, part of the water and water vapor will be pumped directly into the gas pipeline. Secondly, when extracting gas from the goaf, a small amount of grouting water and water vapor will be pumped into the gas pipeline.

(2) Source of debris. There are four types of debris entering the extraction pipeline:

Drilling water carries part of cuttings and dust into the pipeline;

Once the gas pipeline in the goaf is leaked, some mud will be pumped into the pipeline;

The anticorrosive layer and oxide layer on the inner wall of the metal pipe will gradually fall off and stay in the pipe during long-term use;

During the installation of the transportation pipeline, a small amount of debris was left in the pipeline due to negligence.

2, the flow form of water and debris in the pipeline

(1) The flow form of water in a gas pipeline.

Under the action of negative pressure and self-weight, most of the water entering the pipeline flows downward and horizontally along the bottom of the pipeline. Once it encounters unevenness in the pipeline, it will accumulate in the low-lying part of the pipeline;

Water vapor will flow with the gas. Once the temperature drops, part of the water vapor will quickly condense into small water droplets, first land on the bottom of the pipeline, and then flow to the low-lying part of the pipeline;

Under the action of high-speed gas gas, the water atomized into small water particles can flow along with the gas gas. Once the flow rate is reduced, it will fall to the bottom of the pipeline and flow to the low-lying part of the pipeline.

(2) The flow form of dust, drill cuttings and other debris entering the pipeline.

The dust floating in the gas can flow with the gas. When the flow rate is reduced, the particles with larger particles will settle to the bottom of the pipe, and the particles with smaller particles will still be pumped to the pumping station with the gas.

Debris that cannot be impulsed by the flowing water in the pipeline along with the gas flow can flow along the bottom of the pipeline along with the water. When the water velocity decreases, some particles and denser debris will gradually stay at the bottom of the pipe or low-lying areas, and the remaining debris can still flow with the water.

Drilling debris and other debris that cannot flow with water will quickly settle to the bottom of the pipeline, gradually reducing the section of the pipeline and increasing pipeline resistance.

3. Development of continuous automatic water discharge device

Because the intermittent water discharge device cannot continuously discharge water, the water accumulated in the gas drainage pipe with sufficient water supply cannot be discharged in time. Therefore, a continuous automatic water discharge device has been developed to better solve the problem of water accumulation in the gas drainage pipe to the drainage gas. Impact. The structure of the continuous negative pressure automatic water drain is shown in Figure 1. It is mainly composed of a water storage hose, a water inlet distribution system, a negative pressure balance valve, a water storage tank A, a negative pressure balance hose, a vent valve, a water inlet valve, and a floater. Components, water storage tank B, drain valve, etc. Under the negative pressure of pumping, the water storage tank of the water drainer is in a negative pressure state, and both the venting valve and the water draining valve are in the closed position; the water inlet valve of the water inlet distribution system is opened. At the same time, the accumulated water in the gas pipeline flows into the water inlet distribution system through the water storage hose, and preferentially enters the water storage tank A, and the water storage tank B is in the standby water inlet state. With the accumulation of water in the water storage tank A, the float gradually rises. When it floats to a certain height, the negative pressure balance valve connected to the extraction pipe is automatically closed, and the ventilation valve connected to the atmosphere is automatically opened, and the air automatically enters the water storage. In tank A, the water inlet valve is closed immediately. Under the static pressure of the accumulated water, the water discharge valve is opened and water starts to be discharged. With the release of the accumulated water, when the water level in the water storage tank A drops to a certain position, the floating component lowers, so that the negative pressure balance valve opens, the air valve and the water discharge valve are automatically closed under the effect of the pressure difference, and the water inlet valve is opened . Water storage tank A communicates with the gas pipeline again, a negative pressure is formed in the tank again, and the next cycle is entered. At the same time as the water is discharged from the water storage tank A, the water in the extraction pipeline is adjusted by the water inlet system and enters the water storage tank B, and the water storage tank B starts to store water. After the water storage tank A has finished discharging water, the water in the extraction pipeline will enter the water storage tank A again, and the water storage tank B stops the water supply and continues to wait. In such a cycle, the water storage tank B is always used as a reserve for the water storage tank A, and when the water storage tank A discharges water, it replaces the accumulated water stored in the drainage pipeline. This cycle is repeated, and the continuous negative pressure automatic water dispenser realizes continuous automatic water storage and automatic water discharge.

Advantages of the water dispenser:

The accumulated water in the pipeline can be continuously discharged, which makes up for the shortcomings of the single tank water drainer during the water discharge period and the water storage period.

Low failure rate;

Both tanks can work independently. When one tank fails, the other tank can continue to work, and the faulty tank can be inspected and repaired shortly without affecting water discharge;

The water discharge capacity is large, and the larger the amount of incoming water, the better the water release effect;

Discharge water is not affected by negative pressure.

4. Development of separator

Although there are many advantages of continuous automatic water drainers, the influence of debris on the inlet and drain valves has not been completely avoided. There are many drainage holes in each drainage mining well. It is impossible to install a water drainer at each or several drainage holes. Even if the automatic water drainer is fully installed, only some debris in the drainage pipeline can be discharged. , The remaining debris still has a certain impact on gas drainage and utilization. Therefore, according to the different conditions of the drainage site, HMF- and HMF- separators have been developed to suit the drainage site of the two sides of the drainage drilling site and the mining face.

5.Pipe water and debris discharge method

(1) Near the hole. Depending on the drilling location, different separators can be used (HMF- separators are used in the extraction drilling site, and HMF- separators are used in the two lanes of the mining face) and a continuous automatic drain is used to form a combined processing device to process the pipeline. Water and debris.

(2) Low-lying areas of the main pipeline. Because water and debris mainly come from the extraction borehole, as long as the separator and continuous automatic water dispenser are used to intercept and release most of the water and debris in the pipeline near the borehole, the water and debris that enter the main pipeline It is very limited, so there is less water and debris accumulated in the low-lying part of the main pipeline, and the water quality is relatively good. Therefore, the intermittent automatic water discharge device with better installation performance can meet the requirements of water discharge and slag discharge.

(3) Intake side of gas pump or bottom of extraction well. In order to intercept the residual water and debris in the gas, and the debris that was accidentally left in the pipeline during the replacement and reconstruction of the main pipeline, an HMF- type separation can be installed on the gas inlet side of the gas pump or the bottom of the extraction well. And continuous automatic water discharge device, once again intercept and treat the water and debris in the pipeline to ensure that the gas entering the pumping station is free of debris and atomized water. There is not much water and debris that can be intercepted here, and because the place is remote, the drainage management staff checks less often, so it is more reliable to have a continuous automatic water drain. ^[1]