JP7189603B2

JP7189603B2 - Boiler turbine power generation system and power generation method

Info

Publication number: JP7189603B2
Application number: JP2018236097A
Authority: JP
Inventors: 伸治吉田; 良二阿部
Original assignee: 日本エネルギーパートナーズ株式会社
Priority date: 2018-12-18
Filing date: 2018-12-18
Publication date: 2022-12-14
Anticipated expiration: 2038-12-18
Also published as: JP2020098059A

Description

本発明は、リサイクル燃料を燃焼させるボイラによって生成された蒸気を蒸気タービンに導入し、蒸気タービンによって生成された動力を利用して発電するボイラータービン発電システムおよび発電方法に関する。 The present invention relates to a boiler-turbine power generation system and a power generation method for introducing steam generated by a boiler that burns recycled fuel into a steam turbine and using the power generated by the steam turbine to generate power.

従来、ボイラによって生成された蒸気を利用して発電するボイラータービン発電システムが知られている（特許文献１参照）。特許文献１に記載のボイラータービン発電システムは、蒸気発生手段と、過熱器と、第１次タービンと、第２次タービンと、再熱器と、蒸気供給手段と、を備える。この発電システムでは、蒸気発生手段が蒸気を発生させ、過熱器がこの蒸気を過熱し、第１次タービンが過熱された蒸気を導入する。次いで、再熱器が第１次タービンから供給される蒸気を導入して再過熱し、第２次タービンが再熱器によって過熱された蒸気を導入する。蒸気供給手段は、第１次タービンから供給される蒸気または再熱器から供給される蒸気の一部を外部に供給する。 2. Description of the Related Art Conventionally, a boiler turbine power generation system that uses steam generated by a boiler to generate power is known (see Patent Literature 1). The boiler-turbine power generation system described in Patent Document 1 includes steam generating means, a superheater, a primary turbine, a secondary turbine, a reheater, and steam supply means. In this power generation system, the steam generating means generates steam, the superheater superheats this steam, and the primary turbine introduces the superheated steam. A reheater then introduces and resuperheats steam supplied from the primary turbine, and a secondary turbine introduces steam superheated by the reheater. The steam supply means supplies part of the steam supplied from the primary turbine or the steam supplied from the reheater to the outside.

近年、発電事業においても、地球温暖化対策としてＣＯ_２排出量の削減が求められている。そこで、事業用発電ボイラの燃料としてバイオマス等の廃棄物を用いることにより、ＣＯ_２排出量削減をはかる方法がとられてきた（特許文献２参照）。特許文献２に記載の方法では、廃棄物を熱分解炉で加熱することにより塩素を含んだ熱分解ガスとチャー（炭化物）とに熱分解させ、熱分解ガスを燃焼装置で燃焼させ熱分解炉の熱源とし、塩素除去装置によって燃焼ガスから塩素分を除去し、チャーを石炭と混合し、火力発電装置の事業用ボイラで燃焼することにより、廃棄物を処理する。これにより、リサイクル燃料に含まれる塩素等が減少するため、塩素等によってボイラが損傷される可能性が低くなり、事業用ボイラにおけるリサイクル燃料の混焼率を従来よりも上昇させることができる。 In recent years, even in the power generation business, reduction of CO ₂ emissions is required as a countermeasure against global warming. Therefore, a method has been taken to reduce CO ₂ emissions by using waste such as biomass as fuel for a boiler for power generation (see Patent Document 2). In the method described in Patent Document 2, the waste is thermally decomposed into pyrolysis gas containing chlorine and char (carbide) by heating it in a pyrolysis furnace, and the pyrolysis gas is burned in a combustion device to produce a pyrolysis furnace. , the chlorine content is removed from the combustion gas by a chlorine removal device, the char is mixed with coal, and burned in a commercial boiler of a thermal power plant to treat waste. As a result, the amount of chlorine contained in the recycled fuel is reduced, so that the boiler is less likely to be damaged by chlorine, etc., and the co-firing ratio of recycled fuel in commercial boilers can be increased.

特開２００６－２４２５２２JP 2006-242522 特開２００５－２４１９３JP 2005-24193

ところで、地球環境問題の観点からより高い発電効率が求められている。この点、ボイラータービン発電システムにおける発電効率の上昇には、タービンに導入される蒸気の高温化が必要とされる。したがって、タービンに導入される蒸気の高温化をはかるためにボイラの温度を高くする必要があるが、ボイラの温度を高くすると、リサイクル燃料に含まれる塩素等がボイラを損傷する可能性が高まる。そのため、特許文献２に記載の方法によっても、リサイクル燃料による他の燃料との混焼率は、高温のボイラにおいて数％に過ぎず、ＣＯ_２排出量の削減をはかるには不十分であった。 By the way, from the viewpoint of global environmental problems, higher power generation efficiency is required. In this regard, in order to increase the power generation efficiency of a boiler-turbine power generation system, it is necessary to increase the temperature of the steam introduced into the turbine. Therefore, it is necessary to raise the temperature of the boiler in order to increase the temperature of the steam introduced into the turbine. However, if the temperature of the boiler is raised, the chlorine contained in the recycled fuel may damage the boiler. Therefore, even with the method described in Patent Document 2, the co-firing rate of recycled fuel with other fuels is only a few percent in a high-temperature boiler, which is insufficient to reduce _CO2 emissions.

そこで、本発明の課題とするところは、ＣＯ_２排出量の削減をはかるとともに、高い発電効率を保持することができるボイラータービン発電システムおよび発電方法を提供することにある。 Accordingly, an object of the present invention is to provide a boiler-turbine power generation system and power generation method capable of reducing CO ₂ emissions while maintaining high power generation efficiency.

上記課題を解決するために、本発明に係るボイラータービン発電システムは、第１蒸気ドラムと、第２蒸気ドラムと、リサイクル燃料からなる第１燃料を燃焼させ、前記第１蒸気ドラム内に飽和蒸気を発生させるとともに前記送気管を介して前記第１蒸気ドラムの飽和蒸気を前記第２蒸気ドラムに送気する第１ボイラと、前記第１蒸気ドラムから前記第２蒸気ドラムに送気される飽和蒸気の送気量を検出する送気量検出部と、前記送気量検出部によって検出された飽和蒸気の送気量と所定の飽和蒸気の送気量とを比較する送気量比較部と、前記送気量比較部が比較した結果に基づいて、前記第１ボイラに対する前記第１燃料の供給量を調整することにより、前記第１蒸気ドラムから前記第２蒸気ドラムに送気される飽和蒸気の送気量を前記所定の飽和蒸気の送気量に保持する送気量保持部と、第２燃料を燃焼させ、前記第２蒸気ドラム内に飽和蒸気を発生させる第２ボイラと、前記第２ボイラに設けられるとともに、前記第１ボイラおよび前記第２ボイラによって発生させられた前記第２蒸気ドラムの飽和蒸気を過熱して過熱蒸気を生成する過熱器と、前記過熱器によって生成された過熱蒸気を導入し、前記導入された過熱蒸気によって回転させられることにより動力を生成する蒸気タービンと、前記蒸気タービンによって生成された動力によって発電する発電機と、を備えることを特徴とする。 In order to solve the above problems, a boiler-turbine power generation system according to the present invention burns a first steam drum, a second steam drum, and a first fuel composed of a recycled fuel to produce saturated steam in the first steam drum. and a first boiler that supplies saturated steam from the first steam drum to the second steam drum through the air pipe; an air supply amount detection unit for detecting the amount of supplied steam; and an air supply amount comparison unit for comparing the supplied amount of saturated steam detected by the supplied amount detection unit with a predetermined amount of saturated steam supplied. and adjusting the supply amount of the first fuel to the first boiler based on the result of comparison by the air supply amount comparison unit, thereby reducing the amount of saturated air supplied from the first steam drum to the second steam drum. a second boiler that burns a second fuel to generate saturated steam in the second steam drum; a superheater provided in a second boiler for superheating saturated steam in the second steam drum generated by the first boiler and the second boiler to generate superheated steam; A steam turbine that introduces superheated steam and is rotated by the introduced superheated steam to generate power, and a generator that generates power using the power generated by the steam turbine.

上記ボイラータービン発電システムは、前記蒸気タービンに導入される過熱蒸気の流量を調整する蒸気加減弁と、前記発電機による発電量を検出する発電量検出部と、前記発電量検出部によって検出された発電量と所定の発電量とを比較する発電量比較部と、前記発電量比較部が比較した結果に基づいて、前記蒸気加減弁を制御して前記蒸気タービンに導入される過熱蒸気の流量を調整することにより、前記発電機による発電量を前記所定の発電量に保持する発電量保持部と、前記蒸気加減弁より上流に設けられ、前記蒸気加減弁の１次側の過熱蒸気の圧力を検出する圧力検出部と、前記圧力検出部によって検出された過熱蒸気の圧力と所定の過熱蒸気の圧力とを比較する圧力比較部と、前記圧力比較部が比較した結果に基づいて、前記第２ボイラに対する前記第２燃料の供給量を調整することにより、前記蒸気加減弁の１次側の過熱蒸気の圧力を前記所定の過熱蒸気の圧力に保持する圧力保持部と、をさらに備えることが好ましい。 The boiler turbine power generation system includes a steam control valve that adjusts the flow rate of superheated steam introduced into the steam turbine, a power generation amount detection unit that detects the power generation amount of the power generator, and the power generation amount detection unit. a power generation amount comparison unit that compares the power generation amount with a predetermined power generation amount; and based on the result of comparison by the power generation amount comparison unit, the steam control valve is controlled to adjust the flow rate of the superheated steam introduced into the steam turbine. a power generation amount holding unit that maintains the power generation amount of the generator at the predetermined power generation amount by adjusting the pressure of the superheated steam on the primary side of the steam control valve; a pressure detection unit that detects a pressure, a pressure comparison unit that compares the pressure of the superheated steam detected by the pressure detection unit and a predetermined pressure of the superheated steam, and based on the result of comparison made by the pressure comparison unit, the second It is preferable to further include a pressure holding unit that holds the pressure of the superheated steam on the primary side of the steam control valve at the predetermined pressure of the superheated steam by adjusting the supply amount of the second fuel to the boiler. .

上記ボイラータービン発電システムは、例えば、外部の蒸気の需要に応じて、前記外部の需要に対応する量の蒸気を前記蒸気タービンから抽気するとともに、前記外部に供給する蒸気供給部をさらに備えてもよい。 For example, the boiler-turbine power generation system may further include a steam supply unit that extracts steam corresponding to the external demand from the steam turbine and supplies the external steam to the outside. good.

上記ボイラータービン発電システムは、例えば、前記第２燃料が化石燃料であり、前記第２ボイラが微粉炭ボイラでもよい。 In the boiler turbine power generation system, for example, the second fuel may be a fossil fuel, and the second boiler may be a pulverized coal boiler.

上記ボイラータービン発電システムでは、前記第１ボイラが、流動床ボイラであることが好ましい。また、上記ボイラータービン発電システムでは、前記リサイクル燃料が複数の種類から構成されていてもよく、この場合、前記送気量保持部が、前記複数の種類のリサイクル燃料を所定の比率に保ちながら、前記流動床ボイラに供給してもよい。 In the above boiler-turbine power generation system, the first boiler is preferably a fluidized bed boiler. Further, in the above boiler turbine power generation system, the recycled fuel may be composed of a plurality of types. In this case, the air supply amount holding unit maintains the plurality of types of recycled fuel at a predetermined ratio, It may be supplied to the fluidized bed boiler.

上記ボイラータービン発電システムでは、発電計画が存在する場合、この発電計画に基づいて、前記所定の発電量および前記所定の飽和蒸気の送気量が、それぞれ計画的に変動するように構成されることが好ましい。 In the above boiler-turbine power generation system, when a power generation plan exists, the predetermined power generation amount and the predetermined saturated steam supply amount are configured to vary according to plan based on the power generation plan. is preferred.

上記ボイラータービン発電システムでは、前記過熱器が前記第２蒸気ドラムの飽和蒸気を適切に過熱することができるように、前記所定の飽和蒸気の送気量が、前記過熱器の過熱能力に基づいて設定されていることが好ましい。 In the boiler-turbine power generation system, the predetermined amount of saturated steam supplied is based on the superheating capacity of the superheater so that the superheater can appropriately superheat the saturated steam in the second steam drum. preferably set.

上記課題を解決するために、本発明に係る発電方法は、ボイラータービン発電システムによって発電する方法であって、第１ボイラによって、リサイクル燃料である第１燃料を燃焼させ、第１蒸気ドラム内に飽和蒸気を発生させるとともに前記第１蒸気ドラムの飽和蒸気を第２蒸気ドラムに送気し、送気量検出部によって、前記第１蒸気ドラムから前記第２蒸気ドラムに送気される飽和蒸気の送気量を検出し、送気量比較部によって、前記送気量検出部によって検出された飽和蒸気の送気量と、所定の飽和蒸気の送気量とを比較し、送気量保持部によって、前記送気量比較部が比較した結果に基づいて、前記第１ボイラに対する前記第１燃料の供給量を調整することにより、前記第１蒸気ドラムから前記第２蒸気ドラムに送気される飽和蒸気の送気量を前記所定の飽和蒸気の送気量に保持し、第２ボイラによって、第２燃料を燃焼させ、前記第２蒸気ドラム内に飽和蒸気を発生させ、前記第２ボイラに設けられた過熱器によって、前記第１ボイラおよび前記第２ボイラによって発生させられた前記第２蒸気ドラムの飽和蒸気を過熱して過熱蒸気を生成し、蒸気タービンによって、前記過熱器によって生成された過熱蒸気を導入するとともに、前記導入した過熱蒸気によって、前記蒸気タービンを回転させることにより、動力を生成し、発電機によって、前記蒸気タービンが生成した動力を利用して発電することを特徴とする。 In order to solve the above problems, a power generation method according to the present invention is a method of generating power using a boiler-turbine power generation system, wherein a first fuel, which is a recycled fuel, is burned in a first boiler to produce a first fuel in a first steam drum. Saturated steam is generated and the saturated steam in the first steam drum is supplied to the second steam drum, and the amount of saturated steam supplied from the first steam drum to the second steam drum is detected by an air supply amount detection unit. an air supply amount is detected, an air supply amount comparison unit compares the saturated steam supply amount detected by the air supply amount detection unit with a predetermined saturated steam supply amount, and an air supply amount holding unit By adjusting the supply amount of the first fuel to the first boiler based on the result of comparison by the air supply amount comparison unit, air is supplied from the first steam drum to the second steam drum The amount of supplied saturated steam is maintained at the predetermined amount of supplied saturated steam, the second boiler burns the second fuel, generates saturated steam in the second steam drum, and supplies the saturated steam to the second boiler. The provided superheater superheats the saturated steam in the second steam drum generated by the first boiler and the second boiler to generate superheated steam, and the steam turbine generates superheated steam. Power is generated by introducing superheated steam, rotating the steam turbine with the introduced superheated steam, and generating power using the power generated by the steam turbine with a generator. .

上記発電方法は、さらに、発電量検出部によって、前記発電機による発電量を検出し、発電量比較部によって、前記発電量検出部によって検出された発電量と、所定の発電量とを比較し、発電量保持部によって、前記発電量比較部が比較した結果に基づいて、蒸気加減弁を制御して前記蒸気タービンに導入される過熱蒸気の流量を調整することにより、前記発電機による発電量を前記所定の発電量に保持し、前記蒸気加減弁より上流に設けられた圧力検出部によって、前記蒸気加減弁の１次側の過熱蒸気の圧力を検出し、圧力比較部によって、前記圧力検出部によって検出された過熱蒸気の圧力と、所定の過熱蒸気の圧力とを比較し、圧力保持部によって、前記圧力比較部が比較した結果に基づいて、前記第２ボイラに対する前記第２燃料の供給量を調整することにより、前記蒸気加減弁の１次側の過熱蒸気の圧力を前記所定の過熱蒸気の圧力に保持することが好ましい。 In the power generation method, the power generation amount detection unit detects the power generation amount of the generator, and the power generation amount comparison unit compares the power generation amount detected by the power generation amount detection unit with a predetermined power generation amount. and a power generation amount holding unit that controls a steam control valve to adjust the flow rate of superheated steam introduced into the steam turbine based on the result of comparison by the power generation amount comparison unit, thereby increasing the amount of power generated by the generator. is maintained at the predetermined power generation amount, the pressure of the superheated steam on the primary side of the steam control valve is detected by a pressure detection unit provided upstream from the steam control valve, and the pressure detection is performed by a pressure comparison unit The pressure of the superheated steam detected by the unit is compared with a predetermined pressure of the superheated steam, and the pressure holding unit supplies the second fuel to the second boiler based on the comparison result of the pressure comparing unit. It is preferable to maintain the pressure of the superheated steam on the primary side of the steam control valve at the predetermined pressure of the superheated steam by adjusting the amount.

上記発電方法は、例えば、さらに、蒸気供給部によって、外部の蒸気の需要に応じて、前記外部の需要に対応する量の蒸気を前記蒸気タービンから抽気するとともに、前記外部に供給してもよい。 In the power generation method, for example, a steam supply unit may further extract steam in an amount corresponding to the external demand for steam from the steam turbine and supply it to the external according to the external demand for steam. .

上記発電方法では、発電計画が存在する場合、その発電計画に基づいて、前記所定の発電量および前記所定の飽和蒸気の送気量を、それぞれ計画的に変動させることが好ましい。 In the above power generation method, when a power generation plan exists, it is preferable to systematically vary the predetermined power generation amount and the predetermined saturated steam supply amount based on the power generation plan.

上記発電方法では、前記第２ボイラが流動床ボイラであることが好ましい。また、上記発電方法では、前記リサイクル燃料が複数の種類からなる場合、前記送気量保持部によって、前記複数の種類のリサイクル燃料を所定の比率に保ちながら、前記流動床ボイラに供給してもよい。 In the power generation method, it is preferable that the second boiler is a fluidized bed boiler. Further, in the above power generation method, when the recycled fuel is composed of a plurality of types, the supplied air amount holding unit may supply the plurality of types of recycled fuel to the fluidized bed boiler while maintaining a predetermined ratio. good.

上記発電方法では、前記過熱器が前記第２蒸気ドラムの飽和蒸気を適切に過熱することができるように、前記所定の飽和蒸気の送気量が、前記過熱器の過熱能力に基づいて設定されていることが好ましい。 In the power generation method, the predetermined amount of supplied saturated steam is set based on the superheating capacity of the superheater so that the superheater can appropriately superheat the saturated steam in the second steam drum. preferably.

本発明のボイラータービン発電システムおよび発電方法は、ＣＯ_２排出量の削減をはかるとともに、高い発電効率を保持することができる。 INDUSTRIAL APPLICABILITY The boiler-turbine power generation system and power generation method of the present invention can reduce CO ₂ emissions while maintaining high power generation efficiency.

本発明に係るボイラータービン発電システムの概要を示す全体図である。1 is an overall view showing an outline of a boiler-turbine power generation system according to the present invention; FIG. 図１に示した発電システムにおける飽和蒸気の送気量の制御方法を示すフローチャートである。2 is a flowchart showing a method of controlling the amount of saturated steam supplied in the power generation system shown in FIG. 1; 図１に示した発電システムにおける発電量の制御方法を示すフローチャートである。2 is a flowchart showing a method for controlling the power generation amount in the power generation system shown in FIG. 1; 図１に示した発電システムにおける過熱蒸気の圧力の制御方法を示すフローチャートである。2 is a flowchart showing a method for controlling the pressure of superheated steam in the power generation system shown in FIG. 1;

以下、添付図面を参照しつつ、本発明に係るボイラータービン発電システムおよびその発電方法の一実施形態について説明する。 BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a boiler-turbine power generation system and a power generation method thereof according to the present invention will be described below with reference to the accompanying drawings.

図１は、本実施形態に係るボイラータービン発電システム（以下、単に「発電システム」という）Ｓの概要を示す図である。図１に示すように、発電システムＳは、給水部１と、第１蒸気ドラム２と、第２蒸気ドラム３と、第１燃料供給部６と、流動床ボイラ７（第１ボイラ）と、第２燃料供給部８と、微粉炭ボイラ９（第２ボイラ）と、送気管１０と、過熱器１１と、主蒸気管１２と、蒸気タービン１３と、蒸気供給部１４と、復水器１５と、発電機１６と、給水タンク２７と、を備える。 FIG. 1 is a diagram showing an overview of a boiler turbine power generation system (hereinafter simply referred to as "power generation system") S according to this embodiment. As shown in FIG. 1, the power generation system S includes a water supply section 1, a first steam drum 2, a second steam drum 3, a first fuel supply section 6, a fluidized bed boiler 7 (first boiler), A second fuel supply unit 8, a pulverized coal boiler 9 (second boiler), an air pipe 10, a superheater 11, a main steam pipe 12, a steam turbine 13, a steam supply unit 14, and a condenser 15 , a generator 16 , and a water supply tank 27 .

給水部１は、給水弁１ａ、１ｂと、給水弁制御部１ｃ、１ｄと、水位検出部１ｅ、１ｆと、を有する。給水弁制御部１ｃ、１ｄは、給水弁１ａ、１ｂを制御することにより、第１蒸気ドラム２および第２蒸気ドラム３に水を供給する。この水は、発電システムＳによって生成された蒸気によって、予め加熱されている。本実施形態では、第１蒸気ドラム２および第２蒸気ドラム３は、単胴式であるが、水ドラムを有する２胴式や３胴式でもよく、特に限定されない。 The water supply unit 1 includes water supply valves 1a and 1b, water supply valve control units 1c and 1d, and water level detection units 1e and 1f. The water supply valve control units 1c and 1d supply water to the first steam drum 2 and the second steam drum 3 by controlling the water supply valves 1a and 1b. This water has been preheated by the steam generated by the power generation system S. In the present embodiment, the first steam drum 2 and the second steam drum 3 are of a single-barrel type, but may be a two-barrel type or a three-barrel type having a water drum, and are not particularly limited.

水位検出部１ｅは、第１蒸気ドラム２における現在の水位と所定の水位との差を検出し、検出した水位の差を給水弁制御部１ｃに送信する。水位検出部１ｆも同様に、第２蒸気ドラム３における現在の水位と所定の水位との差を検出し、検出した水位の差を給水弁制御部１ｄに送信する。給水弁制御部１ｃ、１ｄは、それぞれ受信した水位の差に基づいて、給水弁１ａ、１ｂを制御して第１蒸気ドラム２、第２蒸気ドラム３に供給する水の量を調整する。これにより、第１蒸気ドラム２および第２蒸気ドラム３の水位は、それぞれ所定の水位に保たれる。 The water level detection unit 1e detects the difference between the current water level in the first steam drum 2 and a predetermined water level, and transmits the detected water level difference to the water supply valve control unit 1c. Similarly, the water level detector 1f also detects the difference between the current water level in the second steam drum 3 and a predetermined water level, and transmits the detected water level difference to the water supply valve controller 1d. The water supply valve controllers 1c and 1d control the water supply valves 1a and 1b to adjust the amount of water supplied to the first steam drum 2 and the second steam drum 3 based on the received water level difference. Thereby, the water levels of the first steam drum 2 and the second steam drum 3 are each kept at a predetermined water level.

第１燃料供給部６は、流動床ボイラ７に第１燃料Ｒを供給する。第１燃料Ｒは、１つまたは複数の種類のリサイクル燃料からなる。本実施形態では、第１燃料Ｒは、ＲＰＦ（Refuse Paper & Plastic Fuel）である２種類のリサイクル燃料Ｒ１、Ｒ２からなるが、単なる一例であってこれに限定されない。第１燃料供給部６は、燃料供給手段６ａ、６ｂを有する。燃料供給手段６ａ、６ｂは、それぞれ第１燃料Ｒ１、Ｒ２を供給する。 The first fuel supply section 6 supplies the first fuel R to the fluidized bed boiler 7 . The first fuel R consists of one or more types of recycled fuel. In this embodiment, the first fuel R consists of two types of recycled fuels R1 and R2, which are RPF (Refuse Paper & Plastic Fuel), but this is merely an example and is not limited to this. The first fuel supply section 6 has fuel supply means 6a and 6b. The fuel supply means 6a, 6b supply first fuels R1, R2, respectively.

流動床ボイラ７は、第１蒸気ドラム２の下方に設けられている。本発明に係る第１ボイラを流動床ボイラ７とすることで、多種の廃棄物からなるリサイクル燃料を燃焼することができる。流動床ボイラ７は、第１蒸気ドラム２の水を導入し、加熱することにより、第１蒸気ドラム２に飽和蒸気を発生させる。具体的には、第１蒸気ドラム２の水が、第１蒸気ドラム２に設けられた降水管（図示しない）によって流動床ボイラ７に導入され加熱されて蒸気となり、蒸発管（図示しない）によって第１蒸気ドラム２に戻される。 A fluidized bed boiler 7 is provided below the first steam drum 2 . By using the fluidized bed boiler 7 as the first boiler according to the present invention, it is possible to burn recycled fuels composed of various types of waste. The fluidized bed boiler 7 introduces the water in the first steam drum 2 and heats it to generate saturated steam in the first steam drum 2 . Specifically, the water in the first steam drum 2 is introduced into the fluidized bed boiler 7 through a downcomer tube (not shown) provided in the first steam drum 2, heated to become steam, and then through an evaporator tube (not shown). It is returned to the first steam drum 2 .

第２燃料供給部８は、微粉炭ボイラ９に第２燃料Ｃを供給する。第２燃料Ｃは、本実施形態では、石炭からなる。第２燃料供給部８は、石炭バンカ８ａと、給炭機８ｂと、ミル（微粉炭機）８ｃと、バーナ８ｄと、を有する。第２燃料Ｃは、石炭バンカ８ａから給炭機８ｂによってミル８ｃに供給され、ミル８ｃによって微粉砕され、燃焼用空気とともにバーナ８ｄから微粉炭ボイラ９内に噴射される。 The second fuel supply unit 8 supplies the second fuel C to the pulverized coal boiler 9 . The second fuel C consists of coal in this embodiment. The second fuel supply section 8 has a coal bunker 8a, a coal feeder 8b, a mill (coal pulverizer) 8c, and a burner 8d. The second fuel C is supplied from the coal bunker 8a to the mill 8c by the coal feeder 8b, pulverized by the mill 8c, and injected into the pulverized coal boiler 9 from the burner 8d together with combustion air.

微粉炭ボイラ９は、第２蒸気ドラム３の下方に設けられている。発電システムＳは、第２ボイラを微粉炭ボイラ９とすることで、高い発電効率を実現するとともにガス、油および種類の異なる石炭同士を混焼することができる。微粉炭ボイラ９は、第２蒸気ドラム３の水を導入し、加熱することにより、第２蒸気ドラム３内に飽和蒸気を発生させる。具体的には、第２蒸気ドラム３の水が、第２蒸気ドラム３に設けられた降水管（図示しない）によって微粉炭ボイラ９に導入され加熱されて蒸気となり、蒸発管（図示しない）によって第２蒸気ドラム３に戻される。 The pulverized coal boiler 9 is provided below the second steam drum 3 . By using the pulverized coal boiler 9 as the second boiler, the power generation system S can achieve high power generation efficiency and co-fire gas, oil, and different types of coal. The pulverized coal boiler 9 introduces water from the second steam drum 3 and heats it to generate saturated steam in the second steam drum 3 . Specifically, the water in the second steam drum 3 is introduced into the pulverized coal boiler 9 through a downcomer tube (not shown) provided in the second steam drum 3, heated to become steam, and then through an evaporator tube (not shown). It is returned to the second steam drum 3 .

送気管１０は、一端部が第１蒸気ドラム２に連結され、他端部が第２蒸気ドラム３に連結されている。流動床ボイラ７は、第１蒸気ドラム２内の飽和蒸気の圧力が第２蒸気ドラム３内の飽和蒸気の圧力よりも高くなるように飽和蒸気を生成することにより、送気管１０を介して第１蒸気ドラム２内の飽和蒸気を第２蒸気ドラム３に送気する。これにより、第２蒸気ドラム３には、流動床ボイラ７によって生成された飽和蒸気と、微粉炭ボイラ９によって生成された飽和蒸気とが混在することとなる。 The air pipe 10 has one end connected to the first steam drum 2 and the other end connected to the second steam drum 3 . The fluidized bed boiler 7 generates saturated steam such that the pressure of the saturated steam in the first steam drum 2 is higher than the pressure of the saturated steam in the second steam drum 3 , thereby supplying the first steam through the air pipe 10 . Saturated steam in the first steam drum 2 is sent to the second steam drum 3 . As a result, the saturated steam generated by the fluidized bed boiler 7 and the saturated steam generated by the pulverized coal boiler 9 are mixed in the second steam drum 3 .

過熱器１１は、長い鋼管と管寄からなり、微粉炭ボイラ９に設けられている。過熱器１１は、第２蒸気ドラム３の飽和蒸気を導入するとともに飽和温度以上に過熱して、過熱蒸気を生成する。過熱器１１の過熱温度は、微粉炭ボイラ９の温度に依存するので、微粉炭ボイラ９に対する第２燃料Ｃの供給量に比例する。 The superheater 11 consists of a long steel pipe and a header, and is installed in the pulverized coal boiler 9 . The superheater 11 introduces the saturated steam of the second steam drum 3 and heats it to a saturation temperature or higher to generate superheated steam. Since the superheating temperature of the superheater 11 depends on the temperature of the pulverized coal boiler 9 , it is proportional to the supply amount of the second fuel C to the pulverized coal boiler 9 .

主蒸気管１２は、一端部が過熱器１１に連結され、他端部が蒸気タービン１３に連結されている。 The main steam pipe 12 has one end connected to the superheater 11 and the other end connected to the steam turbine 13 .

蒸気タービン１３は、主蒸気管１２を介して過熱器１１によって生成された過熱蒸気を導入するとともに、導入した過熱蒸気によって回転させられることにより、動力を生成する。 The steam turbine 13 introduces superheated steam generated by the superheater 11 through the main steam pipe 12, and is rotated by the introduced superheated steam to generate power.

蒸気供給部１４は、蒸気タービン１３に導入された蒸気を抽気するとともに、外部の需要に対応する量の外部用蒸気ＶＯを外部に供給する。外部は、例えば、工場でもよい。さらに、蒸気供給部１４は、抽気した蒸気の所定量を発電システムＳ内用蒸気ＶＩとして発電システムＳ内に供給する。 The steam supply unit 14 bleeds the steam introduced into the steam turbine 13 and supplies external steam VO in an amount corresponding to external demand. The outside may be, for example, a factory. Further, the steam supply unit 14 supplies a predetermined amount of the extracted steam to the inside of the power generation system S as the steam VI for the inside of the power generation system S.

復水器１５は、蒸気タービン１３によって利用された過熱蒸気を水に戻して給水タンク２７に供給する。給水タンク２７に供給された水は、ポンプによって給水部１に供給される。給水部１は、脱気器１ｇと、給水加熱器１ｈと、をさらに有する。給水部１に供給された水は、脱気器１ｇによって非凝縮性ガスを除去され、ポンプによって給水加熱器１ｈに供給され、給水加熱器１ｈによって加熱される。蒸気タービン１３によって、発電システムＳ内に供給された発電システムＳ内用蒸気ＶＩは、脱気器１ｇおよび給水加熱器１ｈにおいて使用される。 The condenser 15 converts the superheated steam utilized by the steam turbine 13 back into water and supplies it to the feedwater tank 27 . The water supplied to the water supply tank 27 is supplied to the water supply unit 1 by a pump. The water supply unit 1 further includes a deaerator 1g and a water supply heater 1h. The water supplied to the water supply unit 1 has non-condensable gas removed by the deaerator 1g, is supplied to the water supply heater 1h by the pump, and is heated by the water supply heater 1h. The steam VI supplied to the power generation system S by the steam turbine 13 is used in the deaerator 1g and the feed water heater 1h.

発電機１６は、蒸気タービン１３に接続されている。発電機１６は、蒸気タービン１３によって生成された動力によって発電し、発電した電力を電力系統に送電する。 A generator 16 is connected to the steam turbine 13 . The generator 16 generates power using the power generated by the steam turbine 13, and transmits the generated power to the power system.

上述のように、発電システムＳでは、過熱器１１が設けられていない流動床ボイラ７においてのみリサイクル燃料Ｒ１、Ｒ２が燃焼されることにより、リサイクル燃料Ｒ１、Ｒ２が高温で燃焼されリサイクル燃料Ｒ１、Ｒ２に含まれる塩素等によって、流動床ボイラ７が損傷させられることが防止される。また、過熱器１１が設けられた微粉炭ボイラ９には、リサイクル燃料Ｒ１、Ｒ２が供給されないので、微粉炭ボイラ９は、リサイクル燃料Ｒ１、Ｒ２に含まれる塩素等によって損傷させられることがない。このように、発電システムＳは、リサイクル燃料Ｒ１、Ｒ２によって設備が損傷させられることを防止することができるので、リサイクル燃料を他の燃料と混焼する従来の発電システムに比して、塩素、硫黄成分等の濃度が高いリサイクル燃料を使用することができ、しかも、発電システムＳ全体の燃料におけるリサイクル燃料Ｒ１、Ｒ２の割合を大幅に高めることもできる。 As described above, in the power generation system S, the recycled fuels R1 and R2 are burned only in the fluidized bed boiler 7 in which the superheater 11 is not provided, so that the recycled fuels R1 and R2 are burned at a high temperature. The fluidized bed boiler 7 is prevented from being damaged by chlorine or the like contained in R2. In addition, since the recycled fuels R1 and R2 are not supplied to the pulverized coal boiler 9 provided with the superheater 11, the pulverized coal boiler 9 is not damaged by chlorine or the like contained in the recycled fuels R1 and R2. In this way, the power generation system S can prevent equipment from being damaged by the recycled fuels R1 and R2. It is possible to use a recycled fuel with a high concentration of components and the like, and it is also possible to significantly increase the ratio of the recycled fuels R1 and R2 in the fuel of the power generation system S as a whole.

次に、図１および図２を参照して、発電システムＳにおける第１蒸気ドラム２から第２蒸気ドラム３に送気される飽和蒸気の送気量の制御について説明する。図１に示すように、発電システムＳは、送気量検出部２４と、送気量比較部２５と、送気量保持部２６と、をさらに備える。 Next, referring to FIGS. 1 and 2, control of the amount of saturated steam supplied from the first steam drum 2 to the second steam drum 3 in the power generation system S will be described. As shown in FIG. 1 , the power generation system S further includes an air supply amount detection unit 24 , an air supply amount comparison unit 25 , and an air supply amount holding unit 26 .

送気量検出部２４は、送気管１０を通って、第１蒸気ドラム２から第２蒸気ドラム３に送気される飽和蒸気の送気量（以下、単に「飽和蒸気の送気量」という）Ｆ１を検出する（図２のＳ１）。 The air supply amount detection unit 24 detects the amount of saturated steam supplied from the first steam drum 2 to the second steam drum 3 through the air supply pipe 10 (hereinafter simply referred to as "the amount of saturated steam supplied"). ) detects F1 (S1 in FIG. 2).

送気量比較部２５は、送気量検出部２４によって検出された飽和蒸気の送気量Ｆ１と、所定の飽和蒸気の送気量ＲＦとを比較する（図２のＳ２）。発電システムＳでは、過熱器１１の過熱能力を超えて飽和蒸気が過熱器１１に過剰に供給されると、過熱器１１が飽和蒸気を適切に過熱できず、生成される過熱蒸気の温度が低下して発電効率が低下する。そこで、高い発電効率を保持するために、発電計画および過熱器１１の過熱能力に基づいて、予め飽和蒸気の送気量を設定している。例えば、夜間における所定の飽和蒸気の送気量ＲＦは、夜間における所定の発電量ＲＱが昼間よりも低く設定されていれば、所定の発電量ＲＱと同様に昼間よりも低く設定される。 The air supply amount comparison unit 25 compares the saturated steam supply amount F1 detected by the air supply amount detection unit 24 with a predetermined saturated steam supply amount RF (S2 in FIG. 2). In the power generation system S, when the saturated steam is excessively supplied to the superheater 11 exceeding the superheating capacity of the superheater 11, the superheater 11 cannot appropriately superheat the saturated steam, and the temperature of the generated superheated steam drops. As a result, power generation efficiency decreases. Therefore, in order to maintain high power generation efficiency, the amount of saturated steam supplied is set in advance based on the power generation plan and the superheating capacity of the superheater 11 . For example, if the predetermined amount of power generation RQ at nighttime is set lower than that during the daytime, the predetermined amount RF of saturated steam supplied at nighttime is set lower than that during the daytime, similarly to the predetermined power generation amount RQ.

送気量保持部２６は、送気量比較部２５が比較した結果に基づいて、流動床ボイラ７に対する第１燃料Ｒ１、Ｒ２の供給量を調整することにより、飽和蒸気の送気量Ｆ１を所定の飽和蒸気の送気量ＲＦに保持する（図２のＳ３～Ｓ５）。具体的には、送気量保持部２６は、送気量比較部２５によって飽和蒸気の送気量Ｆ１が所定の飽和蒸気の送気量ＲＦよりも少ない（すなわち、Ｆ１＜ＲＦ）と判定されると、第１燃料供給部６を制御して流動床ボイラ７に対する第１燃料Ｒ１、Ｒ２の供給量を増加させる（図２のＳ３、Ｓ４）。流動床ボイラ７に対する第１燃料Ｒ１、Ｒ２の供給量が増加すると流動床ボイラ７の温度が上昇するので、流動床ボイラ７によって生成される飽和蒸気量が増加する。一方、送気量保持部２６は、送気量比較部２５によって飽和蒸気の送気量Ｆ１が所定の飽和蒸気の送気量ＲＦよりも多い（すなわち、Ｆ１＞ＲＦ）と判定されると、第１燃料供給部６を制御して流動床ボイラ７に対する第１燃料Ｒ１、Ｒ２の供給量を減少させる（図２のＳ３、Ｓ５）。これにより、送気量保持部２６は、流動床ボイラ７に対する第１燃料Ｒ１、Ｒ２の供給量を増加させるときとは逆の作用によって、流動床ボイラ７が生成する飽和蒸気量を減少させる。 The air supply amount holding unit 26 adjusts the supply amounts of the first fuels R1 and R2 to the fluidized bed boiler 7 based on the result of the comparison by the air supply amount comparison unit 25, thereby adjusting the air supply amount F1 of the saturated steam. The supply amount RF of the saturated steam is maintained at a predetermined value (S3 to S5 in FIG. 2). Specifically, the air supply amount holding unit 26 is determined by the air supply amount comparison unit 25 that the saturated steam supply amount F1 is less than the predetermined saturated steam supply amount RF (that is, F1<RF). Then, the first fuel supply unit 6 is controlled to increase the supply amount of the first fuels R1, R2 to the fluidized bed boiler 7 (S3, S4 in FIG. 2). Since the temperature of the fluidized-bed boiler 7 increases when the amount of the first fuels R1 and R2 supplied to the fluidized-bed boiler 7 increases, the amount of saturated steam generated by the fluidized-bed boiler 7 increases. On the other hand, when the air supply amount comparison unit 25 determines that the air supply amount F1 of saturated steam is larger than the predetermined air supply amount RF of saturated steam (that is, F1>RF), the air supply amount holding unit 26 The first fuel supply unit 6 is controlled to reduce the supply amount of the first fuels R1, R2 to the fluidized bed boiler 7 (S3, S5 in FIG. 2). As a result, the air supply amount holding unit 26 reduces the amount of saturated steam generated by the fluidized bed boiler 7 by an action opposite to when increasing the supply amount of the first fuels R1 and R2 to the fluidized bed boiler 7 .

また、送気量保持部２６は、第１燃料Ｒが複数の種類からなる場合には、第１燃料供給部６を制御し、各燃料を所定の比率に保ちながら流動床ボイラ７に供給してもよい。送気量保持部２６は、第１燃料Ｒ１、Ｒ２を所定の比率で供給することにより、第１燃料Ｒ１、Ｒ２の物性が異なっていても、流動床ボイラ７の温度を定量的に制御し、飽和蒸気の送気量Ｆ１を定量的に制御することができる。 Further, when the first fuel R consists of a plurality of types, the air supply amount holding unit 26 controls the first fuel supply unit 6 to supply each fuel to the fluidized bed boiler 7 while maintaining a predetermined ratio. may By supplying the first fuels R1 and R2 at a predetermined ratio, the air supply amount holding unit 26 quantitatively controls the temperature of the fluidized bed boiler 7 even if the physical properties of the first fuels R1 and R2 are different. , the saturated steam supply amount F1 can be quantitatively controlled.

これらにより、送気量保持部２６は、飽和蒸気の送気量Ｆ１を所定の飽和蒸気の送気量ＲＦに保持するので、過熱器１１の過熱能力を超えて飽和蒸気が過熱器１１に過剰に供給され、生成される過熱蒸気の温度が低下することを防止することができる。したがって、発電システムＳは、高い発電効率を保持することができる。 As a result, the air supply amount holding unit 26 holds the air supply amount F1 of the saturated steam at the predetermined air supply amount RF of the saturated steam. It is possible to prevent the temperature of the superheated steam that is supplied to and generated from dropping. Therefore, the power generation system S can maintain high power generation efficiency.

次に、図１および図３を参照して、発電システムＳにおける発電量の制御について説明する。図１に示すように、発電システムＳは、蒸気加減弁１７と、発電量検出部１８と、発電量比較部１９と、ガバナ２０（発電量保持部）と、をさらに備える。 Next, control of the power generation amount in the power generation system S will be described with reference to FIGS. 1 and 3. FIG. As shown in FIG. 1, the power generation system S further includes a steam control valve 17, a power generation amount detection unit 18, a power generation amount comparison unit 19, and a governor 20 (power generation amount holding unit).

蒸気加減弁１７は、蒸気タービン１３の入口に設けられている。蒸気加減弁１７は、弁開度を調節することにより、蒸気タービン１３に導入される過熱蒸気の流量を調整する。蒸気加減弁１７は、蒸気タービン１３と一体的に構成されていてもよい。 A steam control valve 17 is provided at the inlet of the steam turbine 13 . The steam control valve 17 adjusts the flow rate of the superheated steam introduced into the steam turbine 13 by adjusting the opening degree of the valve. The steam control valve 17 may be configured integrally with the steam turbine 13 .

発電量検出部１８は、発電機１６による発電量Ｑ１を検出する（図３のＳ１）。発電機１６による発電量Ｑ１は、外部の蒸気の需要により変動する。具体的には、蒸気タービン１３によって生成される動力は、蒸気タービン１３に導入された過熱蒸気のうちの一部が復水器１５に排出される前に蒸気供給部１４によって抽気されることにより減少するので、外部の蒸気の需要が変動すると、蒸気供給部１４によって蒸気タービン１３から抽気される抽気蒸気量が変動し、これにより、蒸気タービン１３によって生成される動力が変動し、その結果、発電機１６による発電量Ｑ１も変動する。 The power generation amount detection unit 18 detects the power generation amount Q1 by the generator 16 (S1 in FIG. 3). The amount of power generated Q1 by the generator 16 fluctuates according to the external demand for steam. Specifically, the power generated by the steam turbine 13 is obtained by extracting a part of the superheated steam introduced into the steam turbine 13 by the steam supply unit 14 before being discharged to the condenser 15. As the external steam demand fluctuates, the amount of extracted steam extracted from the steam turbine 13 by the steam supply 14 fluctuates, thereby fluctuating the power produced by the steam turbine 13, resulting in The power generation amount Q1 by the generator 16 also fluctuates.

発電量比較部１９は、発電量検出部１８が検出した発電量Ｑ１と、所定の発電量ＲＱとを比較する（図３のＳ２）。発電システムＳによって発電した電力を売電する場合には、計画的に発電する必要がある。したがって、予め日時ごとに電力系統に送電するための発電量ＲＱが設定されている。所定の発電量ＲＱは、例えば、夜間には、昼間に比して低く設定されていてもよい。 The power generation amount comparison unit 19 compares the power generation amount Q1 detected by the power generation amount detection unit 18 with a predetermined power generation amount RQ (S2 in FIG. 3). When selling the power generated by the power generation system S, it is necessary to generate power in a planned manner. Therefore, a power generation amount RQ for transmitting power to the power system is set in advance for each date and time. For example, the predetermined power generation amount RQ may be set lower at night than during the day.

ガバナ２０は、発電量比較部１９が比較した結果に基づいて、蒸気加減弁１７の弁開度を制御することにより、蒸気タービン１３に導入される過熱蒸気量を制御する（図３のＳ３～Ｓ５）。具体的には、ガバナ２０は、発電量検出部１８によって検出された発電量Ｑ１が所定の発電量ＲＱよりも下回っている（すなわち、Ｑ１＜ＲＱ）ときには、蒸気加減弁１７の弁開度を大きくすることで蒸気タービン１３に供給される過熱蒸気量を増加させ（図３のＳ３、Ｓ４）、発電量検出部１８によって検出された発電量Ｑ１が所定の発電量ＲＱよりも上回っている（すなわち、Ｑ１＞ＲＱ）ときには、蒸気加減弁１７の弁開度を小さくする（図３のＳ３、Ｓ５）ことで蒸気タービン１３に供給される過熱蒸気量を減少させる。これにより、ガバナ２０は、発電機１６による発電量Ｑ１を所定の発電量ＲＱに保持する。 The governor 20 controls the amount of superheated steam introduced into the steam turbine 13 by controlling the valve opening degree of the steam control valve 17 based on the result of the comparison by the power generation amount comparison unit 19 (S3 to S3 in FIG. 3). S5). Specifically, when the power generation amount Q1 detected by the power generation amount detection unit 18 is lower than the predetermined power generation amount RQ (that is, Q1<RQ), the governor 20 reduces the opening degree of the steam control valve 17 to By increasing it, the amount of superheated steam supplied to the steam turbine 13 is increased (S3, S4 in FIG. 3), and the power generation amount Q1 detected by the power generation amount detection unit 18 exceeds the predetermined power generation amount RQ ( That is, when Q1>RQ), the amount of superheated steam supplied to the steam turbine 13 is reduced by reducing the opening degree of the steam control valve 17 (S3, S5 in FIG. 3). As a result, the governor 20 maintains the power generation amount Q1 by the generator 16 at the predetermined power generation amount RQ.

以上のように、発電機１６による発電量Ｑ１は、ガバナ２０によって所定の発電量ＲＱに調整されるので、発電システムＳは、外部による蒸気の需要が変動しても、発電計画に基づいて、電力系統に電力を送電することができる。 As described above, the amount of power generation Q1 by the generator 16 is adjusted to the predetermined amount of power generation RQ by the governor 20. Therefore, even if the demand for steam from the outside fluctuates, the power generation system S can Power can be transmitted to the power grid.

次に、図１および図４を参照して、発電システムＳにおける過熱蒸気の圧力の制御について説明する。図１に示すように、発電システムＳは、圧力検出部２１と、圧力比較部２２と、圧力保持部２３と、をさらに備える。 Next, control of the superheated steam pressure in the power generation system S will be described with reference to FIGS. 1 and 4. FIG. As shown in FIG. 1, the power generation system S further includes a pressure detection section 21, a pressure comparison section 22, and a pressure holding section 23. As shown in FIG.

圧力検出部２１は、主蒸気管１２、すなわち、蒸気加減弁１７より上流に設けられている。圧力検出部２１は、蒸気加減弁１７の１次側の過熱蒸気の圧力Ｐ１を検出する（図４のＳ１）。 The pressure detector 21 is provided upstream from the main steam pipe 12 , that is, the steam control valve 17 . The pressure detector 21 detects the pressure P1 of the superheated steam on the primary side of the steam control valve 17 (S1 in FIG. 4).

圧力比較部２２は、圧力検出部２１が検出した圧力Ｐ１と、所定の過熱蒸気の圧力ＲＰとを比較する（図４のＳ２）。 The pressure comparison unit 22 compares the pressure P1 detected by the pressure detection unit 21 with a predetermined superheated steam pressure RP (S2 in FIG. 4).

発電システムＳの発電効率を高く保持するためには、蒸気タービン１３に導入される過熱蒸気が所定の温度に保持されなければならない。この点、蒸気タービン１３に導入される過熱蒸気の流量が変動すると、過熱蒸気の圧力Ｐ１が変動するとともに蒸気加減弁１７の１次側の過熱蒸気の温度も変動する。そこで、発電システムＳは、目標とする発電効率に基づいて、予め過熱蒸気の圧力ＲＰが設定されており、過熱蒸気の圧力Ｐ１を所定の圧力ＲＰに保持することにより、蒸気タービン１３に導入される過熱蒸気の温度を所定の温度に保持し、高い発電効率を保持する。 In order to keep the power generation efficiency of the power generation system S high, the superheated steam introduced into the steam turbine 13 must be kept at a predetermined temperature. In this regard, when the flow rate of the superheated steam introduced into the steam turbine 13 fluctuates, the pressure P1 of the superheated steam fluctuates and the temperature of the superheated steam on the primary side of the steam control valve 17 also fluctuates. Therefore, in the power generation system S, the pressure RP of the superheated steam is set in advance based on the target power generation efficiency, and by maintaining the pressure P1 of the superheated steam at a predetermined pressure RP, the The temperature of the superheated steam is maintained at a predetermined temperature, and high power generation efficiency is maintained.

なお、蒸気加減弁１７の１次側の過熱蒸気の圧力Ｐ１は、具体的には、過熱器１１が生成する過熱蒸気量と、蒸気タービン１３に導入される過熱蒸気量との差に基づいて変動する。蒸気タービン１３に導入される過熱蒸気量は、所定の発電量ＲＱに対する発電機１６の発電量Ｑ１に基づいて、ガバナ２０によって調整されるところ、発電機１６の発電量Ｑ１は、外部における蒸気の需要に基づく蒸気供給部１４による蒸気の抽気量によって変動する。したがって、蒸気加減弁１７の１次側の過熱蒸気の圧力Ｐ１は、過熱器１１が生成する過熱蒸気量と、外部における蒸気の需要と、所定の発電量ＲＱと、に基づいて変動する。また、過熱器１１が生成する過熱蒸気量は、第１蒸気ドラム２からの飽和蒸気の送気量Ｆ１と、微粉炭ボイラ９によって生成される飽和蒸気量と、の総飽和蒸気量に基づく。飽和蒸気の送気量Ｆ１は、送気量保持部２６によって送気量ＲＦに保持されているので、過熱器１１が生成する過熱蒸気量は、微粉炭ボイラ９が生成する飽和蒸気量によって変動させられる。 Note that the pressure P1 of the superheated steam on the primary side of the steam control valve 17 is specifically based on the difference between the amount of superheated steam generated by the superheater 11 and the amount of superheated steam introduced into the steam turbine 13. fluctuate. The amount of superheated steam introduced into the steam turbine 13 is adjusted by the governor 20 based on the power generation amount Q1 of the generator 16 with respect to the predetermined power generation amount RQ. It varies depending on the amount of steam extracted by the steam supply unit 14 based on demand. Therefore, the superheated steam pressure P1 on the primary side of the steam control valve 17 fluctuates based on the amount of superheated steam generated by the superheater 11, the demand for steam outside, and the predetermined power generation amount RQ. The amount of superheated steam generated by the superheater 11 is based on the total saturated steam amount of the saturated steam supply amount F1 from the first steam drum 2 and the saturated steam amount generated by the pulverized coal boiler 9 . Since the air supply amount F1 of saturated steam is held at the air supply amount RF by the air supply amount holding unit 26, the amount of superheated steam generated by the superheater 11 varies depending on the amount of saturated steam generated by the pulverized coal boiler 9. Let me.

圧力保持部２３は、圧力比較部２２が比較した結果に基づいて、蒸気加減弁１７の１次側の過熱蒸気の圧力Ｐ１を所定の圧力ＲＰに保持する（図４のＳ３～Ｓ５）。具体的には、圧力保持部２３は、圧力比較部２２によって、過熱蒸気の圧力Ｐ１が所定の圧力ＲＰよりも低い（すなわち、Ｐ１＜ＲＰ）と判定されると、給炭機８ｂを制御して微粉炭ボイラ９に対する第２燃料Ｃの供給量を増加させる（図４のＳ３、Ｓ４）。これにより、微粉炭ボイラ９の温度が上昇するので、微粉炭ボイラ９によって生成される飽和蒸気量が増加するとともに過熱器１１に供給される飽和蒸気量も増加し、その結果、過熱器１１によって生成される過熱蒸気量が増加する。また、微粉炭ボイラ９の温度が上昇するとともに過熱器１１の温度も上昇するので、過熱器１１によって生成される過熱蒸気の温度も維持される。一方、圧力保持部２３は、圧力比較部２２によって、過熱蒸気の圧力Ｐ１が所定の圧力ＲＰよりも高い（すなわち、Ｐ１＞ＲＰ）と判定されると、給炭機８ｂを制御して微粉炭ボイラ９に対する第２燃料Ｃの供給量を減少させる（図４のＳ３、Ｓ５）。これにより、圧力保持部２３は、微粉炭ボイラ９に対する第２燃料Ｃの供給量を増加させるときとは逆の作用によって、過熱器１１によって生成される過熱蒸気の圧力を維持しつつ、過熱器１１によって生成される過熱蒸気量を減少させる。これらにより、圧力保持部２３は、過熱蒸気の圧力Ｐ１を所定の圧力ＲＰに保持する。 The pressure holding unit 23 holds the superheated steam pressure P1 on the primary side of the steam control valve 17 at a predetermined pressure RP based on the result of the comparison by the pressure comparing unit 22 (S3 to S5 in FIG. 4). Specifically, when the pressure comparison unit 22 determines that the pressure P1 of the superheated steam is lower than the predetermined pressure RP (that is, P1<RP), the pressure holding unit 23 controls the coal feeder 8b. to increase the supply amount of the second fuel C to the pulverized coal boiler 9 (S3, S4 in FIG. 4). As a result, the temperature of the pulverized coal boiler 9 rises, so the amount of saturated steam generated by the pulverized coal boiler 9 increases and the amount of saturated steam supplied to the superheater 11 also increases. The amount of superheated steam generated increases. Further, as the temperature of the pulverized coal boiler 9 rises, the temperature of the superheater 11 also rises, so the temperature of the superheated steam generated by the superheater 11 is also maintained. On the other hand, when the pressure comparison unit 22 determines that the pressure P1 of the superheated steam is higher than the predetermined pressure RP (that is, P1>RP), the pressure holding unit 23 controls the coal feeder 8b to The supply amount of the second fuel C to the boiler 9 is decreased (S3, S5 in FIG. 4). As a result, the pressure holding unit 23 maintains the pressure of the superheated steam generated by the superheater 11 by an action opposite to the action of increasing the supply amount of the second fuel C to the pulverized coal boiler 9, and 11 to reduce the amount of superheated steam generated. With these, the pressure holding unit 23 holds the pressure P1 of the superheated steam at the predetermined pressure RP.

このように、発電システムＳは、外部の蒸気の需要の変動に基づいて蒸気タービン１３に導入される過熱蒸気量を変動させても、圧力保持部２３によって過熱蒸気の圧力Ｐ１を所定の圧力ＲＰに保持するので、高い発電効率を保持することができる。 In this way, even if the amount of superheated steam introduced into the steam turbine 13 fluctuates based on fluctuations in external steam demand, the power generation system S maintains the pressure P1 of the superheated steam by the pressure holding unit 23 at the predetermined pressure RP. , high power generation efficiency can be maintained.

さらに、発電システムＳは、所定の発電量ＲＱとともに所定の飽和蒸気の送気量ＲＦも発電計画に基づいて設定されているので、発電計画に基づき、ガバナ２０によって蒸気タービン１３に導入される過熱蒸気量を変動させた場合、圧力保持部２３によって微粉炭ボイラ９が生成する飽和蒸気量を変動させるとともに送気量保持部２６によって飽和蒸気の送気量Ｆ１を変動させることにより、過熱器１１によって生成され蒸気タービン１３に導入される過熱蒸気の温度を所定の温度に保持するので、高い発電効率を保持することができる。すなわち、発電システムＳは、夜間等において低く設定された所定の発電量ＲＱに基づいて微粉炭ボイラ９の温度を低下させた場合にも、第１蒸気ドラム２から第２蒸気ドラム３に飽和蒸気が過剰に送気されることを防止するので、過熱器１１によって生成する過熱蒸気の温度が下がり発電効率が低下することを防止することができる。 Further, in the power generation system S, the predetermined power generation amount RQ and the predetermined saturated steam supply amount RF are set based on the power generation plan. When the steam amount is changed, the pressure holding unit 23 changes the saturated steam amount generated by the pulverized coal boiler 9, and the air supply amount holding unit 26 changes the saturated steam supply amount F1, whereby the superheater 11 Since the temperature of the superheated steam generated by and introduced into the steam turbine 13 is maintained at a predetermined temperature, high power generation efficiency can be maintained. That is, in the power generation system S, even when the temperature of the pulverized coal boiler 9 is lowered based on the predetermined power generation amount RQ that is set low at night or the like, the saturated steam is transferred from the first steam drum 2 to the second steam drum 3. is prevented from being excessively supplied, it is possible to prevent the temperature of the superheated steam generated by the superheater 11 from dropping and the power generation efficiency from dropping.

以上のように、発電システムＳおよびその発電方法によれば、第１燃料Ｒ１、Ｒ２を過熱器１１が設けられていない流動床ボイラ７において燃焼させることにより、リサイクル燃料を他の燃料と混焼する従来の発電システムに比して、ＣＯ_２排出量を大きく削減することができる。 As described above, according to the power generation system S and the power generation method thereof, the first fuels R1 and R2 are combusted in the fluidized bed boiler 7 without the superheater 11, thereby co-combusting the recycled fuel with other fuels. Compared to conventional power generation systems, _CO2 emissions can be greatly reduced.

また、発電システムＳおよびその発電方法では、外部の蒸気の需要の変動による発電量Ｑ１の変動に対しては、ガバナ２０による過熱蒸気の流量の制御および圧力保持部２３による第２燃料Ｃの供給量の制御によって対応し、発電計画による所定の発電量ＲＱの変動に対しては、上記２つの制御に加えて送気量保持部２６による第１燃料Ｒ１、Ｒ２の供給量の制御によって対応することにより、所定の発電量ＲＱを保持するとともに高い発電効率を保持することができる。 In addition, in the power generation system S and its power generation method, the flow rate of the superheated steam is controlled by the governor 20 and the second fuel C is supplied by the pressure holding unit 23 in response to fluctuations in the power generation amount Q1 due to fluctuations in external steam demand. In addition to the above two controls, the amount of supply of the first fuels R1 and R2 is controlled by the air supply amount holding unit 26 to cope with fluctuations in the predetermined power generation amount RQ due to the power generation plan. As a result, it is possible to maintain a predetermined power generation amount RQ and maintain high power generation efficiency.

さらに、発電システムＳおよびその発電方法では、高精度の制御が可能な微粉炭ボイラ９を第２ボイラとし、かつ、物性の安定している化石燃料のうちの石炭を第２燃料Ｃとして使用することにより、所定の発電量ＲＱおよび高い発電効率を保持するとともに、安定した運転制御を得ることができる。 Furthermore, in the power generation system S and the power generation method thereof, the pulverized coal boiler 9 that can be controlled with high accuracy is used as the second boiler, and coal, which is a fossil fuel with stable physical properties, is used as the second fuel C. As a result, a predetermined power generation amount RQ and high power generation efficiency can be maintained, and stable operation control can be obtained.

以上、本発明に係る発電システムＳおよびその発電方法の実施形態について説明したが、本発明は、上記実施形態に限定されるものではない。 Although the embodiments of the power generation system S and the power generation method thereof according to the present invention have been described above, the present invention is not limited to the above embodiments.

（１）第１燃料Ｒは、例えば、木質バイオマス燃料（間伐材、建築廃材等）、ＰＫＳ（Palm Kernel Shell）、といったバイオマス燃料、スラッジまたはＲＤＦ（Refuse Derived Fuel）といった廃棄物からなる燃料でもよい。 (1) The first fuel R may be, for example, biomass fuel such as woody biomass fuel (thinned wood, construction waste, etc.), PKS (Palm Kernel Shell), fuel made of waste such as sludge or RDF (Refuse Derived Fuel). .

（２）第２ボイラは、微粉炭ボイラ９に限定されず、例えば、油焚きボイラでもよい。この場合、第２燃料Ｃは、重油でもよい。また、第２ボイラは、ガス焚ボイラでもよい。この場合、第２燃料Ｃは、ＬＰＧ（液化石油ガス）やＬＮＧ（液化天然ガス）などのガスでもよい。 (2) The second boiler is not limited to the pulverized coal boiler 9, and may be an oil-fired boiler, for example. In this case, the second fuel C may be heavy oil. Also, the second boiler may be a gas-fired boiler. In this case, the second fuel C may be gas such as LPG (liquefied petroleum gas) or LNG (liquefied natural gas).

（３）蒸気加減弁１７は、蒸気タービン１３に導入される過熱蒸気の流量を調節できるのであれば、例えば、主蒸気管１２に設けられていてもよい。 (3) The steam control valve 17 may be provided, for example, in the main steam pipe 12 as long as it can adjust the flow rate of superheated steam introduced into the steam turbine 13 .

（４）送気量保持部２６は、第１燃料Ｒが複数の種類からなる場合には、第１燃料供給部６を制御し、第１燃料Ｒのうちの一部の燃料の供給量を固定し、他の燃料の供給量を変動させて、飽和蒸気の送気量Ｆ１を所定の飽和蒸気の送気量ＲＦに保持してもよい。この場合、送気量保持部２６は、供給量を変動する側の燃料供給手段のみを制御することにより、飽和蒸気の送気量Ｆ１を調整する。このように、発電システムＳは、送気量検出部２４、送気量比較部２５および送気量保持部２６を備えていることにより、各燃料間の比率を変動させながら第１燃料Ｒを流動床ボイラ７に供給しつつ、飽和蒸気の送気量Ｆ１を所定の飽和蒸気の送気量ＲＦに保持することができる。 (4) When the first fuel R consists of a plurality of types, the air supply amount holding unit 26 controls the first fuel supply unit 6 to adjust the supply amount of a part of the first fuel R. The saturated steam supply amount F1 may be held at a predetermined saturated steam supply amount RF by fixing it and varying the supply amount of other fuel. In this case, the air supply amount holding unit 26 adjusts the air supply amount F1 of the saturated steam by controlling only the fuel supply means on the side that fluctuates the supply amount. As described above, the power generation system S includes the air supply amount detection unit 24, the air supply amount comparison unit 25, and the air supply amount holding unit 26, so that the first fuel R is changed while varying the ratio between the fuels. While supplying to the fluidized bed boiler 7, the saturated steam supply amount F1 can be maintained at a predetermined saturated steam supply amount RF.

１給水部
１ａ、１ｂ給水弁
１ｃ、１ｄ給水弁制御部
１ｅ、１ｆ水位検出部
１ｇ脱気器
１ｈ給水加熱器
２第１蒸気ドラム
３第２蒸気ドラム
６第１燃料供給部
６ａ、６ｂ燃料供給手段
７流動床ボイラ（第１ボイラ）
８第２燃料供給部
８ａ石炭バンカ
８ｂ給炭機
８ｃミル（微粉炭機）
８ｄバーナ
９微粉炭ボイラ（第２ボイラ）
１０送気管
１１過熱器
１２主蒸気管
１３蒸気タービン
１４蒸気供給部
１５復水器
１６発電機
１７蒸気加減弁
１８発電量検出部
１９発電量比較部
２０ガバナ（発電量保持部）
２１圧力検出部
２２圧力比較部
２３圧力保持部
２４送気量検出部
２５送気量比較部
２６送気量保持部
２７給水タンク
Ｓボイラータービン発電システム
ＶＩ発電システムＳ内用蒸気
ＶＯ外部用蒸気
Ｃ第２燃料
Ｒ１、Ｒ２第１燃料（リサイクル燃料） 1 Water supply units 1a, 1b Water supply valves 1c, 1d Water supply valve control units 1e, 1f Water level detection unit 1g Deaerator 1h Water supply heater 2 First steam drum 3 Second steam drum 6 First fuel supply units 6a, 6b Fuel supply Means 7 fluidized bed boiler (first boiler)
8 second fuel supply unit 8a coal bunker 8b coal feeder 8c mill (pulverizer)
8d burner 9 pulverized coal boiler (second boiler)
10 Air pipe 11 Superheater 12 Main steam pipe 13 Steam turbine 14 Steam supply unit 15 Condenser 16 Generator 17 Steam control valve 18 Power generation amount detection unit 19 Power generation amount comparison unit 20 Governor (power generation amount holding unit)
21 Pressure detection unit 22 Pressure comparison unit 23 Pressure holding unit 24 Air supply amount detection unit 25 Air supply amount comparison unit 26 Air supply amount holding unit 27 Water supply tank S Boiler turbine power generation system VI Power generation system S internal steam VO External steam C Second fuel R1, R2 First fuel (recycled fuel)

Claims

a first steam drum;
a second steam drum;
a first boiler that burns a first fuel made of recycled fuel to generate saturated steam in the first steam drum and feeds the saturated steam in the first steam drum to the second steam drum;
an air supply amount detection unit that detects the amount of saturated steam supplied from the first steam drum to the second steam drum;
an air supply amount comparison unit that compares an air supply amount of saturated steam detected by the air supply amount detection unit with a predetermined air supply amount of saturated steam;
Saturated steam supplied from the first steam drum to the second steam drum by adjusting the supply amount of the first fuel to the first boiler based on the result of comparison by the air supply amount comparison unit an air supply amount holding unit that holds the air supply amount of the above at the predetermined air supply amount of the saturated steam;
a second boiler that burns fossil fuel to generate saturated steam in the second steam drum;
a superheater provided in the second boiler for superheating saturated steam in the second steam drum generated by the first boiler and the second boiler to generate superheated steam;
a steam turbine that introduces superheated steam generated by the superheater and is rotated by the introduced superheated steam to generate power;
a generator that generates power from the power generated by the steam turbine;
a steam control valve that adjusts the flow rate of superheated steam introduced into the steam turbine;
a power generation amount detection unit that detects the power generation amount of the generator;
a power generation amount comparison unit that compares the power generation amount detected by the power generation amount detection unit with a predetermined power generation amount;
Based on the result of comparison by the power generation amount comparison unit, the steam control valve is controlled to adjust the flow rate of the superheated steam introduced into the steam turbine, thereby increasing the power generation amount of the generator to the predetermined power generation amount. a power generation amount holding unit that holds the
a pressure detection unit provided upstream from the steam control valve for detecting the pressure of the superheated steam on the primary side of the steam control valve;
a pressure comparison unit that compares the pressure of the superheated steam detected by the pressure detection unit with a predetermined pressure of the superheated steam;
By adjusting the supply amount of the fossil fuel to the second boiler based on the result of comparison by the pressure comparison unit, the pressure of the superheated steam on the primary side of the steam control valve is reduced to the predetermined pressure of the superheated steam. and a pressure holding unit that maintains the predetermined amount of saturated steam, regardless of the power generation amount detected by the power generation amount detection unit. hold in quantity
A boiler turbine power generation system characterized by:

2. The steam supply unit according to claim 1, further comprising a steam supply unit that bleeds an amount of steam corresponding to the external demand from the steam turbine and supplies the external steam according to the external demand. Boiler turbine power generation system.

3. The boiler-turbine power generation system according to claim 1 , wherein the second boiler is a pulverized coal boiler.

The first boiler is a fluidized bed boiler,
The recycled fuel consists of a plurality of types,
The boiler turbine according to any one of claims 1 to 3 , wherein the air supply amount holding unit supplies the plurality of types of recycled fuel to the fluidized bed boiler while maintaining a predetermined ratio. power generation system.

The boiler turbine power generation according to any one of claims 1 to 4 , wherein the predetermined amount of power generation and the predetermined amount of saturated steam supplied are each systematically varied based on a power generation plan. system.

The predetermined amount of saturated steam supplied is set based on the superheating capacity of the superheater so that the superheater can appropriately superheat the saturated steam in the second steam drum. The boiler turbine power generation system according to any one of claims 1 to 5 .

A method of generating electricity with a boiler turbine power generation system, comprising:
Burning a first fuel, which is a recycled fuel, in a first boiler to generate saturated steam in a first steam drum and feeding the saturated steam in the first steam drum to a second steam drum;
detecting an amount of saturated steam supplied from the first steam drum to the second steam drum by an air supply amount detection unit;
comparing the saturated steam supply amount detected by the air supply amount detection unit with a predetermined saturated steam supply amount by an air supply amount comparison unit;
By adjusting the supply amount of the first fuel to the first boiler based on the result of the comparison by the air supply amount comparison unit, the air supply amount holding unit adjusts the supply amount of the first fuel from the first steam drum to the second steam drum. maintaining the amount of saturated steam supplied to the predetermined saturated steam amount,
burning a fossil fuel with a second boiler to generate saturated steam in the second steam drum;
a superheater provided in the second boiler superheats the saturated steam in the second steam drum generated by the first boiler and the second boiler to generate superheated steam;
introducing superheated steam generated by the superheater into a steam turbine, and generating power by rotating the steam turbine with the introduced superheated steam;
a power generator using the power generated by the steam turbine to generate electricity;
Detecting the amount of power generated by the generator by a power generation amount detection unit,
a power generation amount comparison unit comparing the power generation amount detected by the power generation amount detection unit with a predetermined power generation amount;
The power generation amount holding unit controls the steam control valve to adjust the flow rate of the superheated steam introduced into the steam turbine based on the result of the comparison by the power generation amount comparison unit, thereby increasing the power generation amount of the generator. Maintaining the predetermined amount of power generation,
detecting the pressure of the superheated steam on the primary side of the steam control valve by a pressure detection unit provided upstream from the steam control valve;
The pressure comparing unit compares the pressure of the superheated steam detected by the pressure detecting unit with a predetermined pressure of the superheated steam,
The pressure holding unit adjusts the supply amount of the fossil fuel to the second boiler based on the result of comparison by the pressure comparing unit, thereby maintaining the pressure of the superheated steam on the primary side of the steam control valve at the predetermined level. and hold the superheated steam pressure of
systematically varying the predetermined power generation amount and the predetermined saturated steam supply amount based on a power generation plan,
Further, regardless of the power generation amount detected by the power generation amount detection unit, the amount of recycled fuel supplied is maintained at the predetermined amount of saturated steam supplied.
A power generation method characterized by:

8. The steam supply unit according to the external demand for steam, further extracting from the steam turbine an amount of steam corresponding to the external demand and supplying it to the outside. power generation method.

9. The power generation method according to claim 7 , wherein the predetermined amount of power generation and the predetermined amount of saturated steam supplied are systematically changed based on a power generation plan.

The second boiler is a fluidized bed boiler,
The recycled fuel consists of a plurality of types,
The power generation method according to any one of claims 7 to 9 , wherein the plurality of types of recycled fuel are supplied to the fluidized bed boiler while being maintained at a predetermined ratio by the air supply amount holding unit. .

The predetermined amount of saturated steam supplied is set based on the superheating capacity of the superheater so that the superheater can appropriately superheat the saturated steam in the second steam drum. The power generation method according to any one of claims 7 to 10 .