KR100441943B1 - An Integrated Combined Cycle System using Coal Combustion and Gasification in a Pressurized Circulating Fluidized Bed Reactor - Google Patents

Abstract

The present invention relates to a complex power generation system, and, in a complex power generation system including a gas purifier, a gas turbine combustor, a gas turbine, a high pressure steam turbine, a low pressure steam turbine, and a heat exchanger, gasification generated by pyrolysis and gasification of a supplied fuel A down pipe for moving gas to a gas purification device; A high pressure combustion gas generated by burning the residual gas which has not been gasified in the downcomer, is moved to the gas purifier, and the uncombusted residual gas which is not combusted among the remaining gas is circulated back to the downcomer; And a water cooling pipe that generates high temperature steam by using the heat of combustion generated in the rising pipe and then moves it to a high pressure steam turbine to facilitate transport and control of the solid fuel, and also to operate in low temperature operating conditions and desulfurization. It is a complex power generation system using combustion and gasification in a pressurized circulation fluidized bed which provides a friendly power generation system.

Description

An Integrated Combined Cycle System using Coal Combustion and Gasification in a Pressurized Circulating Fluidized Bed Reactor

The present invention relates to a complex power generation system using a pressurized circulating fluidized bed gasifier, and more particularly, to a combined power generation system in a pressurized circulating fluidized bed to perform gasification and combustion of fuel in a single system.

The pressurized circulating fluidized bed is a reactor operated at a relatively high flow rate under a high pressure atmosphere compared to an atmospheric circulating fluidized bed or a pressurized bubble fluidized bed. One area of fluidized bed technology to perform. Fluidized bed technology has a relatively low operating temperature (below 900 ℃), produces little NOx, can desulfurize in the furnace, and can suppress SOx emissions, making it an environmentally friendly power generation method that does not require a separate desulfurization or denitrification system. have.

The pressurized circulating fluidized bed is a step up from the atmospheric circulating fluidized bed and the pressurized bubble fluidized bed. The application and application of the pressurized circulating fluidized bed is performed by operating the process of the circulating fluidized bed combustor in a pressurized atmosphere. In addition, it has the advantage of performing a large capacity, high efficiency complex power generation.

However, when the pressurized circulating fluidized bed combustor is used for combined power generation, the temperature of the flue-gas flowing into the gas turbine should be operated below 900 ° C, the fluidized bed operation temperature, and there is no expansion due to combustion, resulting in lower efficiency of the gas turbine. . In order to solve this problem, the auxiliary fuel is used to maintain the gas turbine temperature above 1200 ° C, or a separate gasification process is used to improve the efficiency of the gas turbine using some gasification products. .

1 is a block diagram of a combined cycle power generation system using a conventional general gasification and pressure combustion (pressurized bubble fluidized bed). As shown in FIG. 1, the gas 28 is supplied with the fuel 28 and the air 32 from the gasifier 10 having a high temperature (more than 1000 ° C.) and a high pressure (10 to 20 atmospheres), and thus, coal is unreacted. Residual coal of coal, which is a solid fuel (hereinafter referred to as 촤), moves along the 송 transfer line 30 and reacts by burning in a pressurized bubble fluidized bed or other pressurized (10-20 atm) combustion device 12. The high-pressure gasification gas generated from the gasifier 10 and the combustion device 12 and the combustion flue gas are passed through the gas purification device 14 and expanded after combustion in the gas turbine combustor 18 to drive the gas turbine 20. Finally, the generator 26 is driven to produce electricity.

Then, the residual combustion combustion occurs in the pressurized combustion device 12, and the heat generated at this time is used to generate high pressure steam, and the high pressure steam produced drives the high pressure steam turbine 24 to operate the generator 26. To generate electricity. The steam driving the high pressure steam turbine 24 receives the heat from the heat exchanger 16 from the hot gas discharged after driving the gas turbine, and drives the low pressure steam turbine 22 again. It is circulated back to the pressurized combustor 12. On the other hand, the low-temperature gas turbine drive gas that transfers heat from the heat exchanger 16 is discharged to the stack 34.

In the case of the combined power generation using such a general gasification and pressurized combustion (pressurized bubble fluidized bed), the pressurized gasifier and the pressurized combustor must be separately provided, and the residual transfer and control of the gasifier to the combustor is not desired. In addition, in order to supply heat of the gasifier, air (oxygen) must be injected into the gasifier to use partial combustion heat, and this results in a lower heat amount of the gasification product gas.

US Pat. Nos. 5,601,788, US5,911,201, US6,101,983 describe a steam power generation method and a combined power generation method using such a general pressurized circulation fluidized bed, and a combined power generation method using a carbonizer (gasifier). In this patent, a steam turbine power generation system of a pressurized circulation fluidized bed type alone, a combined power generation system using pressurized combustion air, and a carbonizer, which is a kind of a separate gasifier, are used and are very limited in operation and efficiency. In particular, when the gasifier is used separately, it is difficult to select the gasifier material according to the high temperature, maintenance, and ash treatment, and the transfer of the residual gas discharged from the gasifier and the supply to the combustion furnace are very difficult.

The present invention is to solve the problems of the prior art, by performing gasification and combustion at a relatively low temperature (less than 900 ℃) in a single system, to simplify and direct the entire process, thereby stabilizing the system And to improve power generation efficiency.

1 is a block diagram of a hybrid power generation system using a conventional general gasification and pressurized combustion (pressurized bubble fluidized bed), and

2 is a block diagram of a hybrid power generation system using combustion and gasification in a pressurized circulation fluidized bed according to the present invention.

Explanation of symbols on the main parts of the drawing

14: gas purification unit 16: heat exchanger

18: gas turbine burner 20: gas turbine

22: low pressure steam turbine 24: high pressure steam turbine

40: riser 42: downcomer

44: cyclone 46: water cooling tube

In order to achieve the above object, the present invention integrates a descending pipe, which is a gas gasification region, and a rising pipe, which is a fuel combustion region, in a circulating ring type, and in the downpipe, a high-pressure gasification product gas through gasification of fuel. Is used to drive the gas turbine, and the unconverted residual is burned in the riser to generate steam through heat transfer to the boiler water cooling tube to drive the steam turbine and at the same time the high pressure flue gas generated in the riser The present invention provides a combined power generation system using combustion and gasifiers in a pressurized circulation fluidized bed which is used to drive gas turbines together with high-pressure gasification product gases.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a hybrid power generation system using combustion and gasification in a pressurized circulation fluidized bed according to the present invention.

As shown in FIG. 2, the pressurized circulating fluidized bed combustion and gasification combined cycle power generation system of the present invention includes a pressurized circulating fluidized bed combustion and gasifier 50, a gas purifier 14, a heat exchanger 16, and a high pressure gas turbine 20. ), A high pressure steam turbine 24 and a low pressure steam turbine 22.

The pressurized circulating fluidized bed combustion and gasifier 50 is comprised of the downcomer 42 which is the area | region where fuel gasification takes place, and the uprising pipe | tube 40 which is the area | region where fuel burns, and the fuel 28 is the downcomer pipe 42 ), And then gasification (pyrolysis) reaction, and then moves to the riser 40 again to cause a combustion reaction, and again forming a circulation loop to repeat the gasification in the downcomer 42. The gasification product gas generated in the downcomer 42 is discharged to the upper portion of the downcomer 42 and passes through the gas purifier 14 to be burned and expanded in the gas turbine combustor 18 to drive the gas turbine 20. In addition, the high-pressure exhaust gas generated in the riser 40 is introduced into the gas retention device 14 through the upper portion of the riser 40 and the cyclone 44, and passes through the combustor 18 together with the gasification product gas. The turbine 20 is driven.

On the other hand, the heat of combustion due to residual combustion in the riser generates high pressure steam through heat transfer to the water cooling tube 46 to drive the high pressure steam turbine 24. In addition, the high pressure steam passing through the high pressure steam turbine 24 drives the gas turbine 20 and receives heat from the heat exchanger 16 from the high temperature gas discharged to drive the low pressure steam turbine 22.

The operation of the pressurized circulation fluidized bed combustion and gasifier 50 in the combined power generation system using combustion and gasification in the pressurized circulation fluidized bed having such a configuration will be described in more detail.

Pyrolysis and gasification of the fuel are carried out using coal input into the downcomer and the flowing gas in the non-mechanical valve as hot steam. Thereby, generation | occurrence | production of unnecessary gas is prevented and generation | generation of heavy calorific gas is possible.

The residual shock after generation of heavy calorific gas through pyrolysis and gasification of the fuel in the downcomer is circulated through the non-mechanical valve to the upcomer of the pressurized circulation fluidized bed. Here, the non-mechanical valve may be a loop seal, a seal pot, an L-valve, a J-valve, or the like. Thus, the transfer and adjustment of the residual shocks is made smoothly. Residual shock in the riser causes a combustion reaction, and the heat of combustion generated here produces hot steam, so that the combustion and gasification processes are performed stably in a single system.

The amount of heat required for gasification of the fuel in the downcomer is supplemented by the continuous circulation of fuel particles and layered material, thus eliminating the need for an air supply and external heating for separate partial combustion in the downcomer.

The gasification product gas generated in the downcomer flows into the gas turbine and is expanded by combustion with the exhaust gas discharged from the upcoming tube, and has an appropriate temperature rise (1200 to 1300 ° C).

Referring to the effects of the combined power generation system using the combustion and gasifier in the pressurized circulation fluidized bed according to the present invention having the above configuration and action are as follows.

Fuel and solid fuel, which has been a problem in the operation of the conventional gasifier and the combustor, can be easily added and regulated to stabilize the operation, and the required site can be minimized by using a single device.

In addition, by repeatedly circulating gasification and combustion using a pressurized circulation fluidized bed apparatus, the heat supply required for gasification can be provided in a single apparatus by heated solid circulation. As a result, unnecessary air supply can be restricted in the gasification region, and the amount of heat of the gasification product gas can be increased. In addition, the gasification product gas can be used as a secondary fuel of the post-combustion expansion when the gas turbine is driven together with the high pressure relatively low temperature combustion exhaust gas, thereby increasing the efficiency of the gas turbine.

In addition, the introduction of the pressurized circulating fluidized bed device in the hybrid power generation system is operated at a relatively low temperature, and since the desulfurization in the furnace is possible, it is possible to provide a very environmentally friendly power generation method with low emissions of NOx and SOx.

While the invention has been shown and described with respect to certain preferred embodiments thereof, the invention is not limited to these embodiments, and has been claimed by those of ordinary skill in the art to which the invention pertains. It includes all variants of various forms that can be implemented without departing from the technical idea.

Claims (5)

(Correction) by a gas purifier for purifying combustion gas, a gas turbine combustor for combusting the purified combustion gas from the gas stabilization device, a high pressure gas turbine driven by the combustion and expansion of the gas turbine combustor, and high pressure steam In a hybrid power generation system including a high pressure steam turbine driven, a low pressure steam turbine driven by low pressure steam, and a heat exchanger for converting low pressure steam into high pressure steam by heat of a high temperature gas discharged from the high pressure gas turbine. , A downcoming pipe for pyrolysis and gasification when fuel is supplied to move the generated gasification gas to the gas purification apparatus; Air is supplied to combust the remaining gas which has not been gasified in the downcomer, and the high pressure combustion gas is transferred to the gas purifier, and the remaining gas which has not combusted out of the remaining gas is circulated back to the downcomer. ; A cyclone installed between the ascending pipe and the descending pipe, and the exhaust gas generated in the rising pipe passes to move to the gas purification device, and a residual shock remaining in the rising pipe passes to circulate to the descending pipe; And, After the high temperature steam is generated using the combustion heat generated in the riser, the high temperature steam is moved to the high pressure steam turbine, and the low pressure steam passing through the high pressure steam turbine has a pressure in the heat exchanger. And a steam generating means for driving the low pressure steam turbine and receiving low pressure steam from the low pressure steam turbine after being raised. (Correction) The method according to claim 1, A loop seal, a seal pot, an L-valve, or a J-valve may be disposed between the downcoming pipe and the upcoming pipe to move the remaining shock of the downcoming pipe into the upcoming pipe. The combined cycle system using combustion and gasification in the pressurized circulation fluidized bed, characterized in that it further comprises a non-mechanical valve selected from the group. (delete) (delete) (delete)