阅读说明：本技术 一种用于校正地下煤气化炉中气化腔的方法 (method for correcting gasification cavity in underground coal gasifier ) 是由 魏廷锦 于 2019-11-15 设计创作，主要内容包括：一种用于校正地下煤气化炉中气化腔的方法,属于地下煤气化领域,其特征在于：包括将含水流体注入腔的目标区域,从而促进煤在目标区域中的蒸汽汽提和对称生长,从而有效的改善气流模式,减小对流混合面积,缩短停留时间,提高反应速度,含水流体的引入不仅可以增加地下气化器内的煤消耗速率,而且可提高合成气产生的速率,适于推广应用。(A method for correcting the gasification cavity in underground coal gasifier belongs to the field of underground coal gasification, which is characterized in that it comprises injecting aqueous fluid into the target area of the cavity, thereby promoting the steam stripping and symmetric growth of coal in the target area, effectively improving the airflow mode, reducing the convection mixing area, shortening the retention time, increasing the reaction speed, and the introduction of aqueous fluid can not only increase the coal consumption rate in the underground gasifier, but also increase the synthesis gas generation rate, and is suitable for application.)

A method for calibrating a gasification chamber in an underground coal gasifier, comprising injecting an aqueous fluid into a target area of the chamber to promote steam stripping and symmetric growth of coal in the target area of the chamber.

2. The method for calibrating a gasification chamber in an underground coal gasification furnace according to claim 1, wherein: the aqueous fluid is water.

3. The method for calibrating a gasification chamber in an underground coal gasification furnace according to claim 1, wherein: the aqueous fluid is steam.

4. The method for calibrating a gasification chamber in an underground coal gasification furnace according to claim 1, 2 or 3, wherein the aqueous fluid comprises or more chemicals, and the aqueous fluid is injected through a vertical service well.

5, A coal gasification method under ground in coal seam, which comprises injection well, production well and inner well channel connecting injection well and production well, characterized in that it comprises the following steps:

1) establishing a gasification furnace chamber in the coal bed to produce underground coal gasification gas;

2) monitoring the gasification chamber for asymmetric chamber growth and identifying them;

3) drilling a vertical service well into the gasifier cavity in the vicinity of the determined asymmetric cavity growth;

4) an aqueous fluid is injected into the vertical use well to promote steam of the coal in the gasifier cavity area, which will be identified as exhibiting asymmetric cavity growth.

6. A method of gasifying coal underground in a coal seam according to claim 5, characterized by: the aqueous fluid is water.

7. A method of gasifying coal underground in a coal seam according to claim 5, characterized by: the aqueous fluid is steam.

Technical Field

The invention belongs to the field of underground coal gasification, and particularly relates to methods for controlling and correcting a gasification cavity in an underground coal gasification furnace.

Background

The wells are drilled into the coal seam to allow for oxidant injection and product gas extraction, the wells are connected or extended to form slotted well channels to facilitate oxidant injection, cavity development and product gas flow.

Coal seams having injection and production wells are commonly referred to as underground coal gasifiers, which have well channels connecting two wells. Steam stripping is the primary mechanism by which coal is released from the coal seam into the gas phase in an underground gasification process. The natural ingress of water into the gasification chamber from the coal seam and surrounding strata, along with the heat of the gasification process, produces steam that drives the conversion of coal into UCG product gas.

The rate and distribution of water entering the gasification chamber from the coal seam or from the surrounding formation, however, is non-uniform so that the amount of steam generated by naturally occurring water will be greater in regions of the gasification chamber than in other regions.

Disclosure of Invention

The present invention is directed to solving the above problems by providing methods for controlling and calibrating a gasification chamber in an underground coal gasifier.

The method of the present invention for calibrating a gasification chamber in an underground coal gasification furnace includes injecting an aqueous fluid into a target region of the chamber to promote steam stripping and symmetric growth of coal in the target region of the chamber.

The water injected into the gasification chamber in an underground coal gasifier will be converted to steam by the heat in the gasifier or heat associated with the gasifier.

The method for calibrating the gasification cavity of the underground coal gasification furnace is characterized in that the water-containing fluid is steam.

The method for correcting the gasification cavity of the underground coal gasification furnace is characterized in that the aqueous fluid comprises chemicals or a plurality of chemicals, and the aqueous fluid is injected through a vertical service well.

The invention relates to an underground coal gasification method for coal in a coal seam, which comprises an injection well, a production well and an inner seam well channel for connecting the injection well and the production well; the method comprises the following steps:

1) establishing a gasification furnace chamber in the coal bed to produce underground coal gasification gas;

2) monitoring the gasification chamber for asymmetric chamber growth and identifying them;

3) drilling a vertical service well into the gasifier cavity in the vicinity of the determined asymmetric cavity growth;

4) an aqueous fluid is injected into the vertical use well to promote steam of the coal in the gasifier cavity area, which will be identified as exhibiting asymmetric cavity growth.

According to the method for gasifying the coal underground in the coal seam, the water-containing fluid is water.

According to the method for gasifying the coal underground in the coal seam, the water-containing fluid is steam.

The method of the present invention for calibrating a gasification chamber in an underground coal gasification furnace includes injecting an aqueous fluid into a target region of the chamber to promote steam stripping and symmetric growth of coal in the target region of the chamber.

Detailed Description

The method according to the invention for calibrating a gasification chamber in an underground coal gasification furnace is described below by way of example.

Relying on the inherent restriction of natural water flow into the gasification chamber can result in sub-optimal gasifier performance and can create limitations or impediments to optimal UCG operation. For example, natural water ingress is inherently linked to the hydrogeology and geology (e.g., porosity, permeability, saturation, hydrostatic pressure, fault location, etc.) of the coal formation and its surroundings. Furthermore, water ingress may be unevenly distributed over the gasifier cavity, and this may lead to asymmetric growth of the cavity, resulting in poor resource recovery or poor product gas flow through the gasifier. These factors can reduce the volume and/or quality of the syngas produced.

The present invention provides a method for calibrating a gasification chamber in an underground coal gasifier, comprising injecting an aqueous fluid into a target area of the chamber, thereby promoting steam stripping and symmetric growth of coal in the coal.

In embodiments, the aqueous fluid is water, and in another embodiments, the aqueous fluid is steam.

The water may be obtained from a naturally occurring source, such as surface water or groundwater. The water may be fresh water or salt water. The water may be treated water, such as demineralized or raw water separated from the UCG product gas.

The aqueous fluid may be injected alone, or together with the oxidant (or oxidant stream) or as part of the oxidant (or oxidant stream) into the underground gasifier, hi either cases, the aqueous fluid is preferably injected in a controlled manner.

The aqueous fluid may optionally include chemicals or chemicals for conditioning UCG product gas produced in the gasifier before the product gas reaches or leaves the production wells of the gasifier.

For example, a delivery system may be used that includes an existing well (or housing thereof) for delivering other fluids (e.g., oxidants) to the product gas stream.

In another examples, steam (or water) may be injected or delivered through a conduit, and optionally a nozzle or tail is fitted to the lower end of the conduit to inject the steam (or water).

The pipe-based conveyance system may also include a circulation pump and a fluid reservoir connected to the upper end of the pipe, or the pipe-based conveyance system may also include a gas compressor connected to the upper end of the pipe, the diameter of the pipe may be between about 0.5 and 4 inches, preferably between about 1 and 2 inches.

In embodiments where the aqueous fluid is injected with an oxidant, the introduction of the aqueous fluid may increase the rate of coal consumption within the underground gasifier, thereby increasing the rate of syngas production.

In actual use, aqueous fluid may be injected through or more vertical service wells at or more predetermined fixed points (with or without an oxidant), which may help increase resource recovery in the area around the aqueous fluid injection point.

According to important aspects of the invention, at predetermined fixed points (whether through service wells or through some other means), locations or points (aqueous fluid injection may be selected to coincide with regions/zones of the gasification chamber that are remote from the portion(s) of the chamber that receive greater natural water ingress.) the coal seam itself and/or surrounding formations.

As will be appreciated by one of ordinary skill in the art, suitable sensors for monitoring the extent and direction of growth of the gasification chamber include, but are not limited to, thermocouples for sensing temperature (e.g., at the gasification chamber, well passages and/or production wells), gas sensors for detecting UCG product gas properties, and pressure sensors for detecting pressure. The location at which the aqueous fluid is injected into the gasifier and/or the amount of aqueous fluid injected may also be determined and/or adjusted to enhance and/or control the water gas shift reaction. This may be particularly beneficial for applications where it is desirable or important to control or optimize the production or concentration of carbon dioxide and/or hydrogen in the production of syngas.

The heated liquid and/or gas from the UCG process may be recovered and optionally sent to a steam generation system prior to use for further steps.