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Title:
METHOD AND DEVICE FOR DIRECTING OF GASES IN MONO DRILLING UNDERGROUND GASIFICATION OF FUELS
Document Type and Number:
WIPO Patent Application WO/2015/164930
Kind Code:
A2
Abstract:
This method and device are implemented in the energy industry and the underground gasification of fuel. The implementation thereof provides effective gasification process. The method for directing gases consists of using only one drilling for supplying an oxidizing gas and discharging the resulting gas and during the gasification the flow of the oxidising gas increases with the distance from the reaction zone which leads to increase in the linear speed of the oxidising gas and it reaches the reaction front which moved away. The device for implementing the method consists of a casing pipe (1) with pipeline (3) for an oxidizing gas that is mounted coaxially in the pipe and the casing pipe (1) is open in its bottom end with perforations in the walls. The lower part of the pipeline (3) contains a chamber (5) with at least one row of perforated openings (6).

Inventors:
KOVACHKI HRISTO ATANASOV (BG)
ANGELOV ANGEL HRISTOV (BG)
KUNEV RUMEN IVANOV (BG)
Application Number:
PCT/BG2015/000010
Publication Date:
November 05, 2015
Filing Date:
April 22, 2015
Export Citation:
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Assignee:
KOVACHKI HRISTO ATANASOV (BG)
Foreign References:
BG2014000036W2014-10-14
Attorney, Agent or Firm:
DIMITROVA, Krassimira, Hristova (bl. 3 entr. 8 fl., app. 143 1750 Sofia, BG)
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Claims:
1

PATENT CLAIMS

1. Method for directing gases consists of using only one drilling for supplying an oxidizing gas and discharging the resulting gas characterised by the fact that during the gasification the flow of the oxidising gas increases with the distance from the reaction zone which leads to increase in the linear speed of the oxidising gas and it reaches the reaction front which has moved away.

2. Method for directing gases during mono drilling underground gasification of fuels characterised by the fact that is uses device for directing gases and in order to maintain the required flow of oxidising gas in case of accumulation of inert materials the directing structure is pulled up until pressure is normalised when the oxidising gas passes through the openings which were used for discharge of the synthetic gas before the accumulation.

3. The device for directing gases according to the method described in claim 1 consists of a casing pipe with coaxially mounted pipeline for the oxidising gas and the casing pipe is open at the bottom end with perforations in the walls, characterised by a chamber (5) in the lower part of the pipeline (3) with at least one row of perforated openings (6) in the walls.

4. The device described in claim 2 is characterised by an opening (8) in the lower part of the chamber (5) with a diameter greater than the outer diameter of the pipeline.

5. The device described in claims 2 and 3 is characterised by the fact that the chamber opening (5) is located coaxially a mobile burner (7).

6. The device described in claim 2 is characterised by the fact in the lower end of the pipeline (3) there is an upper disk ( 10) and lower disk (11) fixed with a spacer (12) to the upper disk (10).

Description:
METHOD AND DEVICE FOR DIRECTING OF GASES IN

MONO DRILLING UNDERGROUND GASIFICATION OF FUELS

FIELD OF THE INVENTION

This invention relates to a method and a device for direction of gases and finds application in the energy industry for underground gasification of fuels.

BACKGROUND OF THE INVENTION

At present there are two different methods for underground gasification of fossil fuels. The basic principle in the classic variant is the use of two drillings, one for entry of oxidizing gas - air, oxygen or oxygen-enriched air. The other drilling is used to pump out the resulting synthesis gas. This method works for good gas permeability of coal layers, he greater the permeability, the farther deeper will the drillings be, which leads to reduction in investment costs.

The application for Patent PCT/BG2014/00036 describes the method of underground mono drilling gasification of fossil fuels using only one drilling for supplying an oxidizing gas and the discharge of the resulting synthesis gas. This method uses a special casing pipe with a special structure lowered during the drilling. It is open in its lower end and has perforated walls. The perforated area is equal to the height of the coal layer. This pipe shall be lowered close to the end of the coal layer. A pipeline for the oxidising gas passes within. The resulting synthesis gas passes through the casing pipe openings, through the space between the casing pipe and the oxidiser pipe and is discharged at the surface, where it is either burnt or used as raw material for chemical processing. 9

During the underground gasification the carbon and hydrocarbons turn into gas and release greater volumes in the drilling. As a result the reaction front (the limit surface) moves away from the oxidiser supply point and it is more difficult to reach the fossil fuel (Fig. 1), which in turn leads to limiting the increase of the front width. This leads to relatively narrow areas of gasification and the need to have more drillings per unit space of deposit.

The oxidising gas path profile shown on Fig. 1 is due to the supply method. It is obvious that when a pipe open at the lower end is used, the oxidiser flows mainly in the lower layer and after that the greater part enters the perforated part of the casing pipe. In this way, instead of oxidising the fuel, it leaves the reaction zone together with the synthesis gas which is diluted by the oxidiser.

A general problem for underground gasification is that all fossil deposits contain a high percentage of ash (inert materials) and humidity in addition to carbon and carbon containing compounds. During the gasification the carbon, carbon containing compounds and humidity pass into gaseous state. The inert materials however, remain and fall on the bottom of the formed underground cavities.

The classical underground gasification includes several drilling and the ashes block (cover) part of the fossil deposits located in the lower end of the layer. Mono drilling gasification solves this issue because it commences from the lower of the deposit. There is a danger of covering the directing chamber with ash and discontinuing the oxidiser supply.

TECHNICAL BACKGROUND OF THE INVENTION

The task of this invention is to create a method and device with a pipeline structure for mono drilling gasification ensuring effective gasification process. The method for directing gases for mono drilling underground gasification consists of using only one drilling for supplying an oxidizing gas and discharging the resulting gas and during the gasification the flow of the oxidising gas increases with the distance from the reaction zone. This leads to increase in the linear speed of the oxidising gas and it reaches the reaction front which moved away.

The accumulation of significant quantity of inert materials (ash) around the directing chamber is detected when it is necessary to increase significantly the pressure of the oxidiser in order to maintain the flow thereof. This is when the chamber is pulled out to normalise the pressure. The oxidising gas will pass through the openings used for discharge of the synthesis gas (Fig. 5).

This task is solved with a device implementing the described method for directing gases during mono drilling gassification of fuels for this invention including the casing pipe with a coaxially mounted pipeline for the oxidizing gas in the pipe. At the end of the pipeline for the oxidising gas there is a directing structure with fixed size perforations.

The directing chamber for the oxidizing gas is a cylindrical chamber welded to the end of the oxidizing gas pipeline. At the lower end of the walls thereof there are several openings to direct the oxidizing gas to the fossil layer.

Another structure for directing the oxidizing gas for this invention includes two disks at the end of the oxidizing gas pipeline. The upper disk is welded directly at the synthesis gas pipeline and the oxidising gas pipeline and the lower disk is fixed with several spacers to ensure the required distance from the upper disk.

The advantages of the invention are as follows:

provides the required oxidiser for gasification notwithstanding the reaction front distance;

reducing the oxidiser loss;

reducing the diluting of the synthesis gas with oxidising gas; preventing the blocking of the directing chamber with ashes. DESCRIPTION OF THE PRESENTED FIGURES

FIGURE 1

Scheme of movement of the oxidiser and the synthesis gas. The path of the oxidiser is shown with a continuous line and the synthesis gas with continuous. The line between the shaded part and the non-shaded part is the border between the fossil layer and the volume released after the gasification around the drilling. This border is the reaction zone.

FIGURE 2

Scheme of movement of the oxidiser and the synthesis gas and the shape of the released volume when the directing device is used.

FIGURE 3

Chamber like direction device. FIGURE 4

Disk like direction device. FIGURE 5

Movement of the directing device in order to avoid blocking the gasification by the remaining inert mass (ash).

SAMPLE CONSTRUCTION AND APPLICATION OF INVENTION

Sample 1

Directing Chamber Structure

This version is shown on Figure 3. The directing chamber (5) is a cylinder welder to the end of the pipeline (3) for the oxidising gas. Its outer diameter is smaller but close to the outer diameter of the casing pipe (1). In this way, it functions both as a guide for the pipeline during lowering thereof in the casing pipe (1) and as a diluter (9) between the zones with oxidiser (7) and the synthetic gas (4). The lower end of the chamber wall (5) has one or several rows of perforations (6) to direct the oxidiser to the fossil layer. At the bottom of the chamber there is an opening (8) with a diameter greater than the outer diameter of the pipeline (2) for flare gas. The flare burner (7) passes therein and the oxidising gas passes through the opening between the opening and the chamber (5).

In case no flare gas is used, hot oxidising gas is used for flaring thus making the opening at the bottom of the directing chamber redundant.

Sample 2

Directing Disks Structure

The structure shown on Figure 4 intended for directing the oxidising gas includes two disks at the end of the pipeline (3). The upper disk is welded directly on the oxidising gas pipeline (3). It stops the movement of the oxidising gas in the space between the two pipelines. The second lower disk (11) is fixed with several spacers (12) at the required distance from the upper disk. This ensures the required space between the two disks (10) and (11) for the oxidising gas to pass through. Unlike the directing chamber where the gas passes in jets, here it is in the shape of a disk.

Figure 2 shows the released volume when using the directing device. The increase of the volume horizontally reduces the need for additional drilling for the mining of the fossil layer. The principle is as follows:

At the commencement of the gasification, after flaring the fossil layer, the cavity around the drilling is small and the reaction front has small surface with a small oxidiser flow. With the advancement of the process the released volume increases, i.e. the reaction front is increased and this requires an increase of the oxidiser flow in order to maintain gassification speed. This is done by increasing the pressure thereof. The linear sped of the gas leaving the directing device is increased in this way since the openings have a constant area. The higher linear speed allows the gas to move away from the pipeline end and to reach the reaction front which has moved away. In this way the process is regulated only by the oxidiser pressure and maximum effectiveness is achieved notwithstanding the increase of the empty volume.