System for providing superheated steam for gasification furnace by thermal power plant

Abstract

The utility model belongs to the technical field of thermal power plants and coal gasification coupling, and particularly relates to a system for providing superheated steam for a gasification furnace by means of a thermal power plant, which comprises a power station boiler (1) for combusting coal to produce high-temperature and high-pressure main steam and providing the high-temperature and high-pressure main steam to a steam turbine (2), and the steam turbine (2) uses the main steam to generate power; the steam turbine (2) comprises a high-pressure cylinder (21), an intermediate-pressure cylinder (22) and a low-pressure cylinder (23); the gasification furnace (3) is used for producing synthesis gas by using superheated steam, oxygen and coal; and superheated steam used by the gasification furnace (3) is extracted steam of the steam turbine (2). According to the system, part of extracted steam of the steam turbine (2) is provided for the gasification furnace (3) to be used as superheated steam needed by coal gasification, the extracted steam of the steam turbine (2) is coupled with the superheated steam demand of the gasification furnace (3), coal does not need to be burnt additionally to produce the superheated steam, full utilization of the steam and energy integration are achieved, and energy consumption and carbon emission of the system are reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coupling of thermal power plants and coal gasification, and particularly relates to a system for providing superheated steam for a gasifier by a thermal power plant. BACKGROUND

[0002] A conventional coal-fired thermal power plant generates high-temperature and high-pressure steam by a boiler to drive a steam turbine to generate power, but the waste heat utilization rate of the steam turbine exhaust or extraction is low. On the other hand, a gasifier in the field of coal chemical industry usually needs to independently produce superheated steam (usually by burning part of coal or coal gas), resulting in high energy consumption and large carbon emissions. The thermal energy systems of the boiler of the thermal power plant and the gasifier are independently operated, and the cascade utilization of steam energy is not realized, causing energy waste. SUMMARY

[0003] The application provides a system for providing superheated steam for a gasifier by a thermal power plant, comprising:

[0004] a power plant boiler for burning coal to produce high-temperature and high-pressure main steam and providing the main steam to a steam turbine, the steam turbine generating power by using the main steam; the steam turbine comprising a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder;

[0005] a gasifier for producing synthesis gas by using superheated steam, oxygen and coal;

[0006] The superheated steam used by the gasifier is extraction steam of the steam turbine.

[0007] Further, when the power plant boiler is operated at a low load, the extraction steam of the steam turbine is derived from high-pressure cylinder extraction steam.

[0008] Further, when the power plant boiler is operated at a high load, the extraction steam of the steam turbine is derived from medium-pressure cylinder extraction steam.

[0009] Further, when the power plant boiler is operated at a low load, the extraction steam of the steam turbine is derived from high-pressure cylinder extraction steam, and the medium-pressure cylinder extraction steam is extracted by a pressure matching device.

[0010] Further, when the power plant boiler is operated at a low load, the extraction steam of the steam turbine is derived from medium-pressure cylinder extraction steam, and the medium-pressure cylinder extraction steam is provided to the gasifier after being pressurized.

[0011] Further, the saturated steam generated by the gasification of coal by the gasifier is provided to the gasifier after being heated.

[0012] Further, the system further comprises an oxygen pipeline for providing oxygen to the gasifier, and the superheated steam is combined into the oxygen pipeline.

[0013] Further, the synthesis gas is provided to the power plant boiler.

[0014] The above technical solution of the application has at least the following beneficial technical effects:

[0015] This system supplies a portion of the extracted steam from the turbine to the gasifier as superheated steam for the gasification of coal. The turbine extraction steam is coupled with the gasifier's superheated steam demand, eliminating the need to burn coal separately to produce superheated steam. This achieves full utilization of steam and energy integration, reducing system energy consumption and carbon emissions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural diagram of a system that relies on a thermal power plant to provide superheated steam to a gasifier, according to one embodiment of this application.

[0018] in, Figure 1 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0019] 1. Power plant boiler; 2. Steam turbine; 21. High-pressure cylinder; 22. Medium-pressure cylinder; 23. Low-pressure cylinder; 3. Gasifier; 4. Pressure matching device; 5. Steam compressor; 6. Heating device. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0021] Currently, in existing technologies, the thermal energy systems of boilers and gasifiers in thermal power plants are mostly operated independently, failing to fully utilize steam energy and causing energy waste.

[0022] To address the aforementioned problems, one embodiment of this application provides a system that relies on a thermal power plant to provide superheated steam for a gasifier, comprising:

[0023] The power plant boiler 1 of the thermal power plant produces high-temperature and high-pressure main steam by burning coal, and the steam turbine 2 generates electricity by using the main steam; the steam turbine 2 comprises a high-pressure cylinder 21, a medium-pressure cylinder 22 and a low-pressure cylinder 23; wherein the high-pressure cylinder 21, the medium-pressure cylinder 22 and the low-pressure cylinder 23 of the steam turbine 2 can gradiently use the heat and pressure of the high-temperature and high-pressure main steam, and the temperature and pressure of the entering / leaving steam are sequentially reduced along the order of the high-pressure cylinder 21, the medium-pressure cylinder 22 and the low-pressure cylinder 23.

[0024] The system also has a gasifier 3, which uses superheated steam and oxygen to gasify coal to generate synthesis gas; the synthesis gas is a mixed gas containing at least carbon dioxide, carbon monoxide and hydrogen.

[0025] The system provides part of the steam extraction of the steam turbine 2 to the gasifier 3 as the superheated steam required for gasifying coal, and the steam extraction of the steam turbine 2 is coupled with the demand for superheated steam of the gasifier 3, so that there is no need to separately burn coal to produce superheated steam, thereby realizing full utilization of steam and energy integration, and reducing system energy consumption and carbon emissions.

[0026] In a specific embodiment of the present application, when the power plant boiler is running at low load, the steam extraction of the steam turbine 2 is sourced from the high-pressure cylinder 21.

[0027] Alternatively, when the power plant boiler is running at high load, the steam extraction of the steam turbine 2 is sourced from the medium-pressure cylinder 22.

[0028] Alternatively, when the power plant boiler is running at low load, according to the flow rate and pressure of the superheated steam required by the gasifier 3, the steam extraction of the high-pressure cylinder 21 is used to induce the steam extraction of the medium-pressure cylinder 22 through a pressure matcher 4, and then provided to the gasifier 3.

[0029] Alternatively, when the power plant boiler is running at low load, the steam extraction of the medium-pressure cylinder 22 is provided to the gasifier 3 after being pressurized, and the device used for pressurization can be a steam compressor 5.

[0030] In the above technical solution, the matching mode of the gasifier 3 and the steam extraction of the steam turbine 2 can be selected according to demand, and one or a combination of several modes can be selected. Alternatively: when the electricity demand is high and the steam turbine 2 is running at high load, the superheated steam of the gasifier 3 is directly obtained from the steam extraction of the medium-pressure cylinder 22; when the electricity demand is low and the steam turbine 2 is running at low load, the superheated steam of the gasifier 3 is directly obtained from the steam extraction of the high-pressure cylinder 21, or obtained from the steam extractions of the high-pressure cylinder 21 and the medium-pressure cylinder 22 respectively, and then provided to the gasifier 3 after being pressure-regulated by the pressure matcher 4; thereby, according to different loads of the steam turbine 2, the heat and pressure of the steam extraction of the steam turbine 2 are gradiently utilized.

[0031] In one embodiment of the present application, saturated steam is generated when the gasifier 3 gasifies coal, and the saturated steam is superheated and supplied to the gasifier 3 to participate in the coal gasification again, so that the steam and heat energy are fully utilized. Alternatively, the system further comprises a heating device 6 for heating the saturated steam generated by the gasifier 3 to a superheated state.

[0032] Preferably, the system further comprises an oxygen pipeline for supplying oxygen to the gasifier 3. Alternatively, the oxygen pipeline and the superheated steam pipeline are connected to the gasifier 3 respectively, or the superheated steam is incorporated into the oxygen pipeline, and the oxygen and the superheated steam are mixed in a certain proportion before entering the gasifier 3 to participate in the coal gasification.

[0033] In one embodiment of the present application, the syngas produced by the gasifier 3 is directly supplied to the power plant boiler 1, or the separated hydrogen or carbon monoxide is supplied to the power plant boiler 1, to be used for combustion support or to replace part of the coal, so as to reduce fuel consumption and pollutant emission. The waste heat and pressure of the steam extraction of the steam turbine 2 are fully utilized by the gasifier 3, so as to reduce the cold end loss of the traditional coal-fired power plant and improve the overall system thermal efficiency.

[0034] In the description of the present application, the terms "one embodiment", "some embodiments", "certain embodiments", etc. mean that the specific features or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] It should be understood that the above specific embodiments of the present application are only used for illustrative or explanatory purposes, and do not constitute a limitation on the present application. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the claims of the present application are intended to cover all variations and modifications falling within the scope and boundary of the appended claims, or the equivalent forms of such scope and boundary.

Claims

1. A system for providing superheated steam to a gasifier from a thermal power plant, characterized in that, Comprise: a power plant boiler (1) for burning coal to produce high-temperature and high-pressure main steam and provide for a steam turbine (2) which uses the main steam to generate electricity; the steam turbine (2) comprises a high-pressure cylinder (21), a medium-pressure cylinder (22) and a low-pressure cylinder (23); a gasifier (3) for producing synthesis gas by using superheated steam, oxygen and coal; the superheated steam used by the gasifier (3) is extracted steam from the steam turbine (2).

2. The system of claim 1, wherein, When the power plant boiler is running at low load, the extracted steam from the steam turbine (2) is extracted steam from the high-pressure cylinder (21).

3. The system of claim 1, wherein, When the power plant boiler is running at high load, the extracted steam from the steam turbine (2) is extracted steam from the medium-pressure cylinder (22).

4. The system of claim 1, wherein, When the power plant boiler is running at low load, the extracted steam from the steam turbine (2) is extracted steam from the high-pressure cylinder (21) and is used to extract steam from the medium-pressure cylinder (22) through a pressure matching device (4).

5. The system of claim 1, wherein, When the power plant boiler is running at low load, the extracted steam from the steam turbine (2) is extracted steam from the medium-pressure cylinder (22) and is provided to the gasifier (3) after being pressurized.

6. The system of claim 1, wherein, The saturated steam produced by the gasifier (3) when gasifying coal is provided to the gasifier (3) after being heated.

7. The system of claim 1, wherein, It also comprises an oxygen pipeline for providing oxygen to the gasifier (3), and the superheated steam is incorporated into the oxygen pipeline.

8. The system of claim 1, wherein, The synthesis gas is provided to the power plant boiler (1).

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