JP4091791B2

JP4091791B2 - Steam supply method to intermittent steam consumption equipment

Info

Publication number: JP4091791B2
Application number: JP2002138849A
Authority: JP
Inventors: 利光中村; 篤洋徳田
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 2002-05-14
Filing date: 2002-05-14
Publication date: 2008-05-28
Anticipated expiration: 2022-05-14
Also published as: JP2003328703A

Description

【０００１】
【発明の属する技術分野】
本発明は、蒸気発生が間欠的である蒸気（間欠蒸気）を主系統（主蒸気系統）に供給すると共に、蒸気消費量が変動する蒸気間欠消費系統にも供給する蒸気間欠消費設備への蒸気供給方法に関する。
【０００２】
【従来の技術】
転炉で溶銑を吹錬中に発生する転炉ガスは高温であることから、この熱を回収する方法が従来より種々提案されている。例えば、転炉炉口上部を覆うフードなどに間欠蒸気発生装置（例えば熱回収装置）を設けて熱を蒸気として蒸気アキュムレータに回収し、この回収した蒸気を主系統の蒸気管を通して蒸気間欠消費装置（例えば、溶鋼真空処理装置）や他の一般工場装置等の蒸気使用装置に供給している。しかし、転炉は間欠運転のため、蒸気は間欠的に発生する間欠蒸気（ＯＧ蒸気）であって、連続的に利用することが困難であるため、この蒸気を有効に活用する方法が提案されている。
例えば、特開平３−２８５００８号公報には、転炉操業データから予測計算した間欠蒸気の発生量と、蒸気間欠消費装置の操業データから予測計算した蒸気間欠消費装置の蒸気使用量と、現在の蒸気アキュムレータ内の圧力値とから、以降の蒸気アキュムレータ内の圧力を予測計算し、間欠蒸気発生装置以外の他の蒸気発生装置から蒸気間欠消費装置に直接供給するのに必要な間欠蒸気量を演算計算して、流量調整弁を演算した供給量となるように調節する方法が開示されている。これにより、蒸気アキュムレータからの間欠蒸気の供給量が足りないときに、他の蒸気発生装置から直接供給を開始する際や供給停止を行う際、供給量の変化を緩慢にすると共に、供給量の増減を小さくすることが可能となる。
また、特開平４−５０４０７号公報には、間欠蒸気発生装置から発生する間欠蒸気量の予測値と使用蒸気量の予測値とから、蒸気アキュムレータ内の蒸気保有量を時系列的に予測し、この予測値が蒸気アキュムレータの上限保有量を超えるとき、又は下限保有量を下回るときは、予測した時点から上限保有量を超える量と時間、又は下限保有量を下回る量と時間から調整量をそれぞれ演算して求め、その求められた量だけ予め定常的に蒸気を発生する定常蒸気発生装置からの発生蒸気量を調整する方法が開示されている。これにより、間欠蒸気を有効に蒸気間欠消費装置に使用する際に、蒸気の負荷変動を小さくしてバックアップする定常蒸気発生装置を小型化できる。
【０００３】
【発明が解決しようとする課題】
しかしながら、上記した蒸気間欠消費設備への蒸気供給方法には以下の問題がある。
いずれの方法においても予測値を用いるため、転炉吹錬情報の変動等により予測が外れる場合があり、主系統に圧力変動が発生する可能性がある。ここで、主系統の圧力が過昇圧となった場合、主系統の圧力を制御できなくなり、一方、主系統の圧力が低下した場合、蒸気間欠消費装置及び蒸気使用装置へ蒸気を供給できなくなり、安定した操業を行うことができない。このとき、蒸気タービンで圧力変動の吸収を自由に行える場合はよいが、蒸気タービンからの抽気より圧力制御性能（応答速度）が劣る燃料焚きボイラを使用する蒸気系統では圧力変動を吸収できない問題がある。
本発明はかかる事情に鑑みてなされたもので、主系統の圧力変動を制御し安定した操業を行うことができる蒸気間欠消費設備への蒸気供給方法を提供することを目的とする。
【０００４】
【課題を解決するための手段】
前記目的に沿う本発明に係る蒸気間欠消費設備への蒸気供給方法は、蒸気本管に設けられた複数の蒸気使用装置を備えた主蒸気系統に、蒸気発生が間欠的である間欠蒸気系統に備えられた蒸気アキュムレータ内の間欠蒸気を制御弁を介して供給すると共に、蒸気本管に設けられた蒸気消費量が変動する蒸気間欠消費装置を備えた蒸気間欠消費系統に蒸気アキュムレータ内の間欠蒸気を供給する蒸気間欠消費設備への蒸気供給方法において、蒸気間欠消費系統と間欠蒸気系統との間には間欠蒸気を直接供給できる蒸気配管が設けられ、複数の蒸気使用装置及び蒸気間欠消費装置が使用する蒸気量を間欠蒸気系統から供給できない場合は、制御弁による蒸気本管への間欠蒸気の供給制御を、蒸気アキュムレータ内の間欠蒸気の残量を基にして求めた蒸気供給量を最大として、予め設定した流量勾配を用いて行う。このように、現時点での間欠蒸気系統の間欠蒸気量を基に、主蒸気系統へ供給する間欠蒸気の供給制御を行うので、従来のように例えば蒸気アキュムレータ内の間欠蒸気量を予測することなく、間欠蒸気系統から主蒸気系統へ間欠蒸気を供給できる。
ここで、本発明に係る蒸気間欠消費設備への蒸気供給方法において、間欠蒸気の蒸気供給量は、以下の式を用いて求められることが好ましい。
Ｑｇｅｎ≦−Ｑｒｈ＋（Ｑｒｈ²＋２×Ｋ×Ｖａｃｃ）^1/2
ここで、Ｑｇｅｎは間欠蒸気系統から主蒸気系統への間欠蒸気の供給流量、Ｑｒｈは間欠蒸気系統から蒸気間欠消費系統への間欠蒸気の供給流量、Ｋは間欠蒸気系統から主蒸気系統へ供給する間欠蒸気の流量勾配、Ｖａｃｃは蒸気アキュムレータ内の間欠蒸気の残量である。これにより、蒸気間欠消費系統に使用する間欠蒸気量を考慮すると共に、主蒸気系統へ供給可能な間欠蒸気量を容易に把握できる。
【０００５】
本発明に係る蒸気間欠消費設備への蒸気供給方法において、主蒸気系統には、主蒸気系統に蒸気を供給できる補充蒸気系統を設けると共に、主蒸気系統と補充蒸気系統との間には逆止弁を設け、蒸気アキュムレータ内の間欠蒸気の圧力値が低下し、主蒸気系統の蒸気の圧力が補充蒸気系統の補充蒸気の圧力より低下した場合、主蒸気系統の蒸気と補充蒸気との差圧により、逆止弁を介して補充蒸気系統から主蒸気系統へ補充蒸気を供給し、また蒸気アキュムレータ内の間欠蒸気の圧力値が上昇し、主蒸気系統の蒸気の圧力が補充蒸気の圧力より高くなった場合、逆止弁により補充蒸気系統から主蒸気系統への補充蒸気の供給を停止することが好ましい。このように、逆止弁により補充蒸気系統から主蒸気系統への補充蒸気の供給を制御するので、主蒸気系統の蒸気の圧力に応じて補充蒸気系統からの補充蒸気の供給及び停止を自動的に行うことができる。
本発明に係る蒸気間欠消費設備への蒸気供給方法において、制御弁は、流量制御と圧力制御との切替えを行うことができ、制御弁により、主蒸気系統の蒸気の圧力が予め設定した所定圧力未満の場合、主蒸気系統へ流れる間欠蒸気の流量を制御し、また主蒸気系統の蒸気の圧力が所定圧力以上の場合、主蒸気系統へ流れる間欠蒸気の圧力を制御することが好ましい。このように、制御弁により間欠蒸気系統から主蒸気系統への間欠蒸気の供給方法を変えるので、蒸気アキュムレータから主蒸気系統へ供給する間欠蒸気を、主蒸気系統の蒸気の圧力が所定圧力未満の場合は流量制御によって最大供給し、過昇圧時のみ圧力を制御して供給できる。
【０００６】
【発明の実施の形態】
続いて、添付した図面を参照しつつ、本発明を具体化した実施の形態につき説明し、本発明の理解に供する。
ここに、図１は本発明の一実施の形態に係る蒸気間欠消費設備への蒸気供給方法を適用する蒸気供給設備の説明図、図２は同蒸気間欠消費設備への蒸気供給方法を適用した供給制御の説明図である。
【０００７】
図１に示すように、本発明の一実施の形態に係る蒸気間欠消費設備への蒸気供給方法を適用する蒸気供給設備１０は、蒸気発生量が変動するＯＧボイラ（間欠蒸気発生装置の一例）１１を備えた間欠蒸気系統１２と、間欠蒸気系統１２からの間欠蒸気が供給される複数の蒸気使用装置１３が設けられた蒸気本管１４を備えた主蒸気系統（主系統とも言う）１５と、間欠蒸気系統１２から供給される間欠蒸気の圧力が低下した場合、主蒸気系統１５へ補充蒸気を供給する燃料焚きボイラ（補充蒸気発生装置の一例）１６を備えた補充蒸気系統１７とを有する設備である。なお、この蒸気供給設備１０の各装置は、制御用コンピュータ等の制御装置（図示しない）によって稼動される。以下、詳しく説明する。
【０００８】
間欠蒸気系統１２において、ＯＧボイラ１１は、回収した転炉ガスの潜熱及び顕熱の熱交換により高温高圧の蒸気を発生させるものであり、その製造される間欠蒸気量は単位時間当り例えば０〜４００ｔの範囲で変動し、平均８０〜９０ｔ程度である。このＯＧボイラ１１は、転炉（図示しない）の数に応じて１又は２以上設置することが可能であり、ＯＧボイラ１１には配管１８が接続されている。この配管１８の上流側には分岐点Ｘが設けられ、分岐点Ｘから分岐した支管１９には放散弁２０が備えられている。これにより、ＯＧボイラ１１が設けられた間欠蒸気系統１２の間欠蒸気の圧力が過昇圧となった場合は、放散弁２０によって間欠蒸気を排気し、間欠蒸気の圧力を調整することも可能である。
また、配管１８の分岐点Ｘの下流側には分岐点Ｙが設けられ、分岐点Ｙから分岐した支管２１の下流側端部には、ＯＧボイラ１１で製造した蒸気を貯蔵する蒸気アキュムレータ２２（例えば、容量が３００ｍ³ 程度）が、１又は２以上設けられている。なお、この蒸気アキュムレータ２２内の圧力（例えば、最大で３．７ＭＰａ程度）は圧力計（図示しない）で測定され、この測定圧力が制御装置に入力されている。更に、配管１８の分岐点Ｙの下流側には減圧弁２３が設けられ、例えば３．７ＭＰａの蒸気を例えば２．０ＭＰａ（この実施の形態においては１．９ＭＰａ）程度に減圧している。
【０００９】
補充蒸気系統１７において、燃料焚きボイラ１６は、連続的に高温高圧の蒸気を発生させるものであり、その製造される補充蒸気量は単位時間当り例えば６０〜１２０ｔ程度である。なお、ここでは、燃料焚きボイラ１６を２台配置しているが、１台でもよく、また３台以上配置することも可能である。この燃料焚きボイラ１６には配管２４が接続され、この配管２４には分岐点Ｚが設けられている。この分岐点Ｚから分岐した支管２５の下流側端部には、蒸気タービン発電機２６が備えられ、この燃料焚きボイラ１６で発生した補充蒸気を単位時間当り例えば２０〜１２０ｔ程度呑込み、電力を例えば３〜２４ＭＷ程度発生させる。
なお、配管２４中の補充蒸気は、蒸気タービン発電機２６を稼動させることで、圧力が例えば１．５ＭＰａ程度に制御されている。
【００１０】
間欠蒸気系統１２の配管１８の下流側端部には、流量制御と圧力制御との切替えを行う制御弁２７が設けられ、この制御弁２７を介して主蒸気系統１５の蒸気本管１４に接続されている。これにより、間欠蒸気は制御弁２７を介して蒸気本管１４へと供給され、更にこの蒸気本管１４から複数の蒸気使用装置１３へと供給される。
また、補充蒸気系統１７の配管２４の下流側端部には逆止弁２８が設けられ、この逆止弁２８を介して主蒸気系統１５の蒸気本管１４に接続されている。これにより、間欠蒸気系統１２から供給される間欠蒸気の圧力が低下し、主蒸気系統１５の蒸気の圧力が補充蒸気の圧力より低下した場合、補充蒸気系統１７から主蒸気系統１５への補充蒸気の供給が可能となる。一方、間欠蒸気系統１２から主蒸気系統１５へ間欠蒸気が供給され、主蒸気系統１５の蒸気の圧力が補充蒸気の圧力より高い場合、主蒸気系統１５から補充蒸気系統１７への蒸気の流れ込みを防止できる。このように、簡単な構成で主蒸気系統１５への補充蒸気の流れ込みを制御できるので、経済的である。
【００１１】
主蒸気系統１５の蒸気本管１４中の蒸気は、所定圧力、即ち１．６ＭＰａ（例えば、２００〜３００℃程度）に設定され、蒸気供給設備１０を安定に操業させるために、例えば１．５〜１．６ＭＰａ程度（管理値）の範囲で管理されている。この蒸気本管１４には、蒸気消費量が変動する蒸気間欠消費装置の一例である溶鋼真空処理装置（ＲＨ脱ガス装置）２９を備えた蒸気間欠消費系統３０が設けられている。この溶鋼真空処理装置２９は、間欠的（例えば、１０〜１５分程度の間）に単位時間当り例えば２０〜８０ｔの蒸気を使用するものであり、稼動しない場合は蒸気の使用量がゼロである。溶鋼真空処理装置２９には配管３１が接続されている。
【００１２】
この配管３１の下流側には圧力調整弁３２が設けられているので、制御装置によって所定の圧力（例えば、０．７〜０．９ＭＰａ）に調整された蒸気が溶鋼真空処理装置２９へ供給できる。この配管３１に設けられた圧力調整弁３２の上流側には、分岐点Ｐが設けられ、分岐点Ｐから分岐した支管３３の先側には、溶鋼真空処理装置２９へ供給するための蒸気を貯蔵する蒸気アキュムレータ３４（例えば、容量が５０〜１００ｍ³ 程度）が、１又は２以上設けられている。
この配管３１の分岐点Ｐの上流側端部には、予め設定した所定の速度勾配にて蒸気の供給及び停止を行うことができる制御弁３５が設けられ、この制御弁３５を介して主蒸気系統１５の蒸気本管１４に接続されている。これにより、主蒸気系統１５から蒸気間欠消費系統３０へ蒸気の供給及び停止を行うことが可能となる。
【００１３】
また、間欠蒸気系統１２の配管１８に設けられた分岐点Ｑと、蒸気間欠消費系統３０の配管３１に設けれた分岐点Ｐとの間には、間欠蒸気系統１２から蒸気間欠消費系統３０へ間欠蒸気を直接供給できる蒸気配管３６が設けられている。この蒸気配管３６の途中には圧力調整弁３７が設けられ、間欠蒸気系統１２から供給される間欠蒸気を、蒸気配管３６を介して制御装置により所定の圧力で蒸気間欠消費系統３０へ供給している。この圧力調整弁３７の圧力は、制御弁２７の圧力より低い圧力に制御されているので、間欠蒸気系統１２から主蒸気系統１５へ間欠蒸気を供給できなくなった場合においても、間欠蒸気系統１２から蒸気間欠消費系統３０へ蒸気を供給できる。従って、間欠蒸気系統１２の蒸気アキュムレータ２２内に蓄積された間欠蒸気をより多く（差圧分）供給できる。
【００１４】
このように、間欠蒸気系統１２から蒸気間欠消費系統３０へ蒸気配管３６を介して間欠蒸気を供給することで、蒸気間欠消費装置２９の稼動の有無に係わらず、蒸気本管１４の蒸気の圧力を安定操業可能なレベルに制御できるので、蒸気本管１４の外乱を防止し、蒸気供給設備１０を安定に操業でき作業性が良好となる。なお、前記した間欠蒸気系統１２、主蒸気系統１５、補助蒸気系統１７、蒸気間欠消費系統３０を流れる各蒸気の圧力は、配管１８、蒸気本管１４、配管２４、配管３１にそれぞれ設けられたセンサーによって感知され、制御装置に送られ、制御されている。
【００１５】
次に、本発明の一実施の形態に係る蒸気間欠消費設備への蒸気供給方法について、前記した蒸気供給設備１０、図１、図２を参照しながら説明する。
通常、間欠蒸気系統１２の蒸気アキュムレータ２２内の間欠蒸気の測定圧力が十分に高い場合、即ち、複数の蒸気使用装置１３及び溶鋼真空処理装置２９が使用する全蒸気量を、蒸気アキュムレータ２２から供給できる場合は、測定圧力に基づき、制御装置によって制御弁２７及び圧力調整弁３７をそれぞれ開状態とし、蒸気本管１４と蒸気配管３６の両方へ間欠蒸気を供給する（図２中の転炉吹錬中）。
【００１６】
ここで、蒸気アキュムレータ２２内に貯蔵された間欠蒸気の測定圧力が低くなってきた場合、即ち、複数の蒸気使用装置１３及び溶鋼真空処理装置２９が使用する全蒸気量を蒸気アキュムレータ２２から供給できなくなってきた場合は、例えば、蒸気アキュムレータ２２内の間欠蒸気の圧力が１．８ＭＰａ程度となる前までに、測定圧力に基づき制御装置によって制御弁２７による間欠蒸気の供給制御を行う（図２中の転炉吹錬停止）。なお、このとき、蒸気配管３６への間欠蒸気の供給は行われるが、主蒸気系統１５の蒸気の圧力が補充蒸気の圧力より低下するので、主蒸気系統１５の蒸気と補充蒸気との差圧により、逆止弁２８を介して補充蒸気系統１７から主蒸気系統１５への補充蒸気の供給が行われる。また、蒸気配管３６を流れる間欠蒸気の圧力は、蒸気本管１４へ供給される間欠蒸気の圧力より低く設定されているので、間欠蒸気の圧力が蒸気配管３６を流れる間欠蒸気の設定圧力より高い間は、間欠蒸気系統１２から蒸気本管１４への間欠蒸気の供給を流量制御し、更に停止した場合でも、間欠蒸気系統１２から蒸気間欠消費系統３０への間欠蒸気の供給は行われる。
【００１７】
ここで、間欠蒸気の供給制御について説明する。
蒸気アキュムレータ２２に蓄積された間欠蒸気を、蒸気配管３６へ供給流量Ｑｒｈ（ｔ／ｈ）で供給することで、溶鋼真空処理装置２９への安定供給を保証しつつ、蒸気アキュムレータ２２内の間欠蒸気の圧力値に応じて、蒸気本管１４へ予め設定した流量勾配Ｋ（例えば、２７０ｔ／ｈ² 程度）で増減しながら供給流量Ｑｇｅｎ（ｔ／ｈ）で供給するには、以下で求められる蒸気量を確保する必要がある。なお、この蒸気量は、蒸気アキュムレータ２２の蓄積蒸気量（間欠蒸気の残量）Ｖａｃｃ（ｔ）を使って計算する。また、蒸気アキュムレータ２２の蓄積蒸気量は、蒸気アキュムレータ２２内の測定圧力、蒸気のエンタルピー、蒸気アキュムレータ２２内の熱水比容積等を用いて求められる。
【００１８】
図２に示すように、蒸気アキュムレータ２２から蒸気本管１４への供給流量Ｑｇｅｎを、勾配Ｋで０（ｔ／ｈ）にするまでに必要な蒸気量は、三角形Ｘの面積で示される。また、供給流量Ｑｇｅｎが０（ｔ／ｈ）になるまでに、供給流量Ｑｒｈ（ｔ／ｈ）で溶鋼真空処理装置２９へ供給しなければならない蒸気量は、四角形Ｙの面積で示される。この四角形Ｙの面積は、溶鋼真空処理装置２９で使用されるＱｒｈ４及びＱｒｈ５に必要な蒸気量以上の蒸気量であればよい。
これにより、前記した確保する必要がある蒸気量は、三角形Ｘ及び四角形Ｙで囲まれる面積で示される。この関係を（１）式に示す。
Ｖａｃｃ≧（Ｑｇｅｎ×Ｑｇｅｎ／Ｋ）／２＋Ｑｒｈ×Ｑｇｅｎ／Ｋ・・（１）
【００１９】
次に（１）式を、Ｑｇｅｎについて整理した式を（２）式に示す。
Ｑｇｅｎ≦−Ｑｒｈ＋（Ｑｒｈ² ＋２×Ｋ×Ｖａｃｃ）^1/2 ・・・（２）
ここで、Ｑｇｅｎは間欠蒸気系統１２の蒸気アキュムレータ２２から主蒸気系統１５の蒸気本管１４への間欠蒸気の供給流量、Ｑｒｈは間欠蒸気系統１２の蒸気アキュムレータ２２から蒸気間欠消費系統３０への間欠蒸気の供給流量、Ｋは間欠蒸気系統１２の蒸気アキュムレータ２２から主蒸気系統１５の蒸気本管１４へ供給する間欠蒸気の流量勾配、Ｖａｃｃは蒸気アキュムレータ２２内の間欠蒸気の残量である。
【００２０】
（２）式を満足する最大のＱｇｅｎで間欠蒸気を蒸気本管１４へ供給すれば、溶鋼真空処理装置２９への間欠蒸気の安定供給を保証しながら、最大限間欠蒸気を活用できる。
ここで、主蒸気系統１５の蒸気の圧力が所定圧力（１．６ＭＰａ）未満の場合、制御弁２７の制御を流量制御に切替え、間欠蒸気の供給量に速度勾配を設け、蒸気アキュムレータ２２に蓄積された間欠蒸気を最大限供給できるように流量制御を行う。一方、主蒸気系統１５の蒸気の圧力が所定圧力以上の場合、制御弁２７の制御を圧力制御に切替え、主蒸気系統１５への間欠蒸気の導入量を制限し、蒸気本管１４へ流れる間欠蒸気の圧力を１．６ＭＰａに制御する。つまり、制御弁２７により、常時は（２）式に基づいて流量制御を行い、蒸気本管１４の需要がＱｇｅｎより小さくなった場合に、圧力制御を行う。
なお、制御弁２７の制御は、（２）式の計算結果から得られたＱｇｅｎの目標値と、実際に流れているＱｇｅｎの実績値との偏差をみて制御する例えばＰＩＤ制御によって行い、制御弁２７を連続的に稼動させることで行う。
【００２１】
ここで、蒸気アキュムレータ２２内の間欠蒸気の測定圧力が、蒸気間欠消費系統３０へ供給できない圧力値まで減少すれば、間欠蒸気系統１２から蒸気間欠消費系統３０への間欠蒸気の供給も停止する。このため、間欠蒸気系統１２から蒸気本管１４への蒸気供給を停止する蒸気アキュムレータ２２内の蒸気圧力より低い（例えば、制御弁２７が閉状態となる圧力値より０．１〜０．２ＭＰａ程度低い）測定圧力で、制御装置によって制御弁３５を開状態とし、例えば前記流量勾配Ｋで蒸気本管１４から蒸気間欠消費系統３０へ蒸気を供給する。この供給量を、図２中の三角形Ｚの面積に対応させることで、間欠蒸気系統１２から供給できなくなった間欠蒸気の不足分を補うことが可能となる。
これにより、主蒸気系統１５の蒸気本管１４の圧力外乱が、１つの系統から発生することとなるので、圧力変動を容易に制御できる。
【００２２】
一方、再度、転炉の吹錬が開始され、間欠蒸気系統１２の蒸気アキュムレータ２２内に貯蔵された間欠蒸気量が十分に貯蔵されて、複数の蒸気使用装置１３及び溶鋼真空処理装置２９が使用する全蒸気量を、蒸気アキュムレータ２２から供給できる場合（例えば、蒸気アキュムレータ２２内の間欠蒸気の圧力が１．８ＭＰａ程度まで増加した場合）は、溶鋼真空処理装置２９が停止した状態で、前記した条件と逆の方法を用い、測定圧力に基づき制御装置によって制御弁３５を閉状態とし、再度蒸気配管３６を介して、間欠蒸気系統１２から蒸気間欠消費系統３０への間欠蒸気の供給を開始すると共に流量制御を行う。なお、このとき、間欠蒸気系統１２の間欠蒸気の圧力が上昇することで、蒸気本管１４の蒸気の圧力が補充蒸気の圧力より高くなった場合、逆止弁２８によって補助蒸気系統１７から蒸気本管１４への補助蒸気の供給が停止され、間欠蒸気系統１２から蒸気本管１４への間欠蒸気の供給が再開される。
これにより、主蒸気系統１５の蒸気本管１４内の蒸気の圧力は、間欠蒸気の供給の有無に影響されることなく、管理値の範囲内で制御することができる。
【００２３】
以上、本発明を、一実施の形態を参照して説明してきたが、本発明は何ら上記した実施の形態に記載の構成に限定されるものではなく、特許請求の範囲に記載されている事項の範囲内で考えられるその他の実施の形態や変形例も含むものである。
例えば、前記した実施の形態や変形例の一部又は全部を組合せて本発明の蒸気間欠消費設備への蒸気供給方法を構成する場合にも本発明は適用される。
また、前記実施の形態においては、補充蒸気発生装置として燃料焚きボイラを使用した場合について説明した。しかし、他の補充蒸気発生装置、例えばコークスの冷却時に発生する熱を利用するＣＤＱを備えることも可能である。
【００２４】
【発明の効果】
請求項１〜４記載の蒸気間欠消費設備への蒸気供給方法においては、現時点での間欠蒸気系統の間欠蒸気量を基に、主蒸気系統へ供給する間欠蒸気の供給制御を行うので、従来のように例えば蒸気アキュムレータ内の間欠蒸気量を予測することなく、間欠蒸気系統から主蒸気系統へ間欠蒸気を供給できる。従って、例えば急な予定変更による予測外れの影響等を考慮することなく、蒸気本管の蒸気の圧力を安定操業可能なレベルに制御できるので、設備を安定に操業できる。また、蒸気アキュムレータ内の間欠蒸気をより多く供給できるので、例えば間欠蒸気の貯蔵を行う蒸気アキュムレータの容量を変えることなく、蒸気の貯蔵量を増やすことが可能となる。このため、新たな設備投資に要する製造コストを抑制できると共に、蒸気アキュムレータに貯蔵できない間欠蒸気の大気への放散量を従来より減少でき経済的である。
特に、請求項２記載の蒸気間欠消費設備への蒸気供給方法においては、蒸気間欠消費系統に使用する間欠蒸気量を考慮すると共に、主蒸気系統へ供給可能な間欠蒸気量を容易に把握できるので、蒸気間欠消費装置を安定に稼動できる。
【００２５】
請求項３記載の蒸気間欠消費設備への蒸気供給方法においては、逆止弁により補充蒸気系統から主蒸気系統への補充蒸気の供給を制御するので、主蒸気系統の蒸気の圧力に応じて補充蒸気系統からの補充蒸気の供給及び停止を自動的に行うことができる。従って、間欠蒸気系統から主蒸気系統への間欠蒸気の供給量に影響されることなく、主蒸気系統の蒸気の圧力を安定操業可能なレベルに制御できるので、設備を安定に操業でき作業性が良好となる。また、間欠蒸気が蒸気アキュムレータから主蒸気系統へ大量供給可能な場合は、間欠蒸気のみを主蒸気系統へ供給できるので、例えば間欠蒸気を大気へ放散することなく使用でき経済的である。
請求項４記載の蒸気間欠消費設備への蒸気供給方法においては、制御弁により蒸気アキュムレータから主蒸気系統への間欠蒸気の供給方法を変えるので、蒸気アキュムレータから主蒸気系統へ供給する間欠蒸気を、主蒸気系統の蒸気の圧力が所定圧力未満の場合は流量制御によって最大供給し、過昇圧時のみ圧力を制御して供給できる。従って、間欠蒸気を大量供給可能な場合には、補充蒸気系統から主蒸気系統への補充蒸気の供給を行うことなく、主蒸気系統へ間欠蒸気を供給できるので、補充蒸気系統を使用する必要がなく経済的である。また、主蒸気系統の蒸気の圧力が過昇圧の場合には、主蒸気系統へ供給する間欠蒸気の圧力を制御して供給するので、更に設備を安定に操業でき作業性が良好となる。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係る蒸気間欠消費設備への蒸気供給方法を適用する蒸気供給設備の説明図である。
【図２】同蒸気間欠消費設備への蒸気供給方法を適用した供給制御の説明図である。
【符号の説明】
１０：蒸気供給設備、１１：ＯＧボイラ（間欠蒸気発生装置）、１２：間欠蒸気系統、１３：蒸気使用装置、１４：蒸気本管、１５：主蒸気系統、１６：燃料焚きボイラ（補充蒸気発生装置）、１７：補充蒸気系統、１８：配管、１９：支管、２０：放散弁、２１：支管、２２：蒸気アキュムレータ、２３：減圧弁、２４：配管、２５：支管、２６：蒸気タービン発電機、２７：制御弁、２８：逆止弁、２９：溶鋼真空処理装置（蒸気間欠消費装置）、３０：蒸気間欠消費系統、３１：配管、３２：圧力調整弁、３３：支管、３４：蒸気アキュムレータ、３５：制御弁、３６：蒸気配管、３７：圧力調整弁[0001]
BACKGROUND OF THE INVENTION
The present invention supplies steam to an intermittent steam consumption facility that supplies intermittent steam (intermittent steam) to a main system (main steam system) and also supplies to an intermittent steam consumption system in which steam consumption varies. It relates to a supply method.
[0002]
[Prior art]
Since the converter gas generated during hot metal blowing in the converter is high temperature, various methods for recovering this heat have been proposed. For example, an intermittent steam generator (for example, a heat recovery device) is provided in a hood or the like that covers the upper part of the converter furnace mouth, and heat is recovered as steam into a steam accumulator, and the recovered steam is passed through the steam pipe of the main system to intermittent steam consumption (E.g., molten steel vacuum processing equipment) and other general factory equipment and other steam using equipment. However, since the converter is operated intermittently, the steam is intermittent steam (OG steam) that is generated intermittently and is difficult to use continuously. Therefore, a method for effectively utilizing this steam has been proposed. ing.
For example, in Japanese Patent Laid-Open No. 3-285008, the intermittent steam generation amount predicted from the converter operation data, the steam usage amount of the intermittent steam consumption device predicted from the operation data of the intermittent steam consumption device, and the current From the pressure value in the steam accumulator, the subsequent pressure in the steam accumulator is predicted and calculated, and the amount of intermittent steam required to supply the steam intermittent consumption device directly from other steam generators other than the intermittent steam generator is calculated. A method of calculating and adjusting the flow rate adjustment valve so as to be the calculated supply amount is disclosed. As a result, when the supply amount of intermittent steam from the steam accumulator is insufficient, when the supply is started directly from another steam generator or when the supply is stopped, the change in the supply amount is slowed and the supply amount is reduced. The increase / decrease can be reduced.
Further, in JP-A-4-50407, the amount of steam held in the steam accumulator is predicted in time series from the predicted value of the intermittent steam amount generated from the intermittent steam generator and the predicted value of the used steam amount, When this predicted value exceeds the upper limit holding amount of the steam accumulator or falls below the lower limit holding amount, the amount and time exceeding the upper limit holding amount from the predicted time point, or the adjustment amount from the amount and time below the lower limit holding amount, respectively. There is disclosed a method for adjusting the amount of steam generated from a steady steam generator that calculates and calculates steam in a steady manner in advance by the calculated amount. Thereby, when using intermittent steam for an intermittent steam consumption apparatus effectively, the steady steam generator which backs up by reducing the load fluctuation of steam can be reduced in size.
[0003]
[Problems to be solved by the invention]
However, the above steam supply method to the intermittent steam consumption equipment has the following problems.
In any method, since the predicted value is used, the prediction may be lost due to fluctuations in the converter blowing information, and pressure fluctuations may occur in the main system. Here, when the pressure of the main system is over-pressurized, it becomes impossible to control the pressure of the main system, while when the pressure of the main system decreases, it becomes impossible to supply steam to the steam intermittent consumption device and the steam using device, Stable operation cannot be performed. At this time, it is good if the steam turbine can absorb pressure fluctuations freely, but the steam system using a fuel-fired boiler whose pressure control performance (response speed) is inferior to the extraction from the steam turbine cannot absorb the pressure fluctuations. is there.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for supplying steam to an intermittent steam consumption facility capable of controlling the pressure fluctuation of the main system and performing stable operation.
[0004]
[Means for Solving the Problems]
The steam supply method to the steam intermittent consumption equipment according to the present invention that meets the above-mentioned object is an intermittent steam system in which steam generation is intermittent in a main steam system including a plurality of steam using devices provided in a steam main. The intermittent steam in the steam accumulator is supplied to the intermittent steam consumption system provided with the intermittent steam consumption device provided in the steam main and supplying the intermittent steam in the steam accumulator. In the steam supply method to the intermittent steam consumption facility for supplying steam, a steam pipe capable of directly supplying intermittent steam is provided between the intermittent steam consumption system and the intermittent steam system, and a plurality of steam use devices and intermittent steam consumption devices are provided. If the amount of steam to be used cannot be supplied from the intermittent steam system, the intermittent steam supply control to the steam main by the control valve is performed.The maximum amount of steam obtained based onThis is performed using a preset flow rate gradient. Thus, since intermittent supply control of the intermittent steam supplied to the main steam system is performed based on the intermittent steam quantity of the intermittent steam system at the present time, for example, without predicting the intermittent steam quantity in the steam accumulator as in the past. The intermittent steam can be supplied from the intermittent steam system to the main steam system.
Here, in the steam supply method to the steam intermittent consumption facility according to the present invention, the intermittent steamSteam supplyUsing the following formula:AskingIt is preferable that
Qgen ≦ −Qrh + (Qrh²+2 x K x Vacc)^1/2
Here, Qgen is the supply flow rate of intermittent steam from the intermittent steam system to the main steam system, Qrh is the supply flow rate of intermittent steam from the intermittent steam system to the intermittent steam consumption system, and K is supplied from the intermittent steam system to the main steam system. The flow rate gradient of intermittent steam, Vacc, is the remaining amount of intermittent steam in the steam accumulator. Thereby, while considering the intermittent steam volume used for an intermittent steam consumption system, the intermittent steam volume which can be supplied to the main steam system can be grasped easily.
[0005]
In the steam supply method to the intermittent steam consumption facility according to the present invention, the main steam system is provided with a supplemental steam system capable of supplying steam to the main steam system, and a check is not provided between the main steam system and the supplemental steam system. When the pressure value of the intermittent steam in the steam accumulator is reduced and the steam pressure in the main steam system is lower than the supplementary steam pressure in the supplementary steam system, a differential pressure between the steam in the main steam system and the supplementary steam is provided. As a result, supplementary steam is supplied from the supplementary steam system to the main steam system via the check valve, the pressure value of the intermittent steam in the steam accumulator rises, and the steam pressure in the main steam system is higher than the pressure of the supplementary steam. In this case, it is preferable to stop the supply of the supplemental steam from the supplemental steam system to the main steam system by the check valve. In this way, the supply of supplementary steam from the supplementary steam system to the main steam system is controlled by the check valve, so that supply and stoppage of supplementary steam from the supplementary steam system are automatically performed according to the steam pressure of the main steam system. Can be done.
In the steam supply method to the intermittent steam consumption facility according to the present invention, the control valve can perform switching between flow rate control and pressure control, and the control valve sets a predetermined pressure at which the steam pressure of the main steam system is preset. If it is less than the range, it is preferable to control the flow rate of the intermittent steam flowing to the main steam system, and to control the pressure of the intermittent steam flowing to the main steam system when the steam pressure of the main steam system is equal to or higher than a predetermined pressure. In this way, the intermittent steam supply method from the intermittent steam system to the main steam system is changed by the control valve, so that the intermittent steam supplied from the steam accumulator to the main steam system is less than the predetermined pressure. In this case, the maximum supply can be performed by the flow rate control, and the pressure can be controlled and supplied only at the time of excessive pressure increase.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory diagram of a steam supply facility to which the steam supply method to the intermittent steam consumption facility according to one embodiment of the present invention is applied, and FIG. 2 is an application of the steam supply method to the intermittent steam consumption facility. It is explanatory drawing of supply control.
[0007]
As shown in FIG. 1, a steam supply facility 10 to which a steam supply method to a steam intermittent consumption facility according to an embodiment of the present invention is applied is an OG boiler (an example of an intermittent steam generator) whose steam generation amount varies. A main steam system (also referred to as a main system) 15 provided with a steam main pipe 14 provided with a plurality of steam using devices 13 to which intermittent steam from the intermittent steam system 12 is supplied; And a supplemental steam system 17 having a fuel-fired boiler (an example of a supplemental steam generator) 16 for supplying supplemental steam to the main steam system 15 when the pressure of the intermittent steam supplied from the intermittent steam system 12 decreases. Equipment. Each device of the steam supply facility 10 is operated by a control device (not shown) such as a control computer. This will be described in detail below.
[0008]
In the intermittent steam system 12, the OG boiler 11 generates high-temperature and high-pressure steam by exchanging latent heat and sensible heat of the recovered converter gas, and the amount of intermittent steam produced is, for example, 0 to 0 per unit time. It fluctuates in the range of 400t, and the average is about 80-90t. One or two or more OG boilers 11 can be installed depending on the number of converters (not shown), and a pipe 18 is connected to the OG boiler 11. A branch point X is provided on the upstream side of the pipe 18, and a branch valve 19 branched from the branch point X is provided with a diffusion valve 20. Thereby, when the pressure of the intermittent steam of the intermittent steam system 12 provided with the OG boiler 11 becomes an excessive pressure, the intermittent steam can be exhausted by the diffusion valve 20 and the pressure of the intermittent steam can be adjusted. .
Further, a branch point Y is provided on the downstream side of the branch point X of the pipe 18, and a steam accumulator 22 (stores the steam produced by the OG boiler 11) at the downstream end of the branch pipe 21 branched from the branch point Y. For example, capacity is 300m^Three 1) or 2 or more. Note that the pressure in the steam accumulator 22 (for example, about 3.7 MPa at the maximum) is measured by a pressure gauge (not shown), and this measured pressure is input to the control device. Further, a pressure reducing valve 23 is provided on the downstream side of the branch point Y of the pipe 18 to depressurize, for example, 3.7 MPa steam to, for example, about 2.0 MPa (1.9 MPa in this embodiment).
[0009]
In the supplementary steam system 17, the fuel-fired boiler 16 continuously generates high-temperature and high-pressure steam, and the amount of supplementary steam produced is, for example, about 60 to 120 t per unit time. Here, two fuel-fired boilers 16 are disposed, but one may be disposed, or three or more may be disposed. A pipe 24 is connected to the fuel-fired boiler 16, and a branch point Z is provided in the pipe 24. A steam turbine generator 26 is provided at the downstream end of the branch pipe 25 branched from the branch point Z. The replenished steam generated in the fuel-fired boiler 16 is charged for about 20 to 120 t per unit time, for example. For example, about 3 to 24 MW is generated.
The supplementary steam in the pipe 24 is controlled to have a pressure of, for example, about 1.5 MPa by operating the steam turbine generator 26.
[0010]
A control valve 27 for switching between flow rate control and pressure control is provided at the downstream end of the pipe 18 of the intermittent steam system 12, and is connected to the steam main pipe 14 of the main steam system 15 via the control valve 27. Has been. Thereby, the intermittent steam is supplied to the steam main pipe 14 via the control valve 27, and further supplied from the steam main pipe 14 to the plurality of steam using devices 13.
A check valve 28 is provided at the downstream end of the pipe 24 of the supplementary steam system 17, and is connected to the steam main pipe 14 of the main steam system 15 via the check valve 28. Thereby, when the pressure of the intermittent steam supplied from the intermittent steam system 12 decreases and the pressure of the steam of the main steam system 15 decreases below the pressure of the supplemental steam, the supplemental steam from the supplemental steam system 17 to the main steam system 15 is obtained. Can be supplied. On the other hand, when intermittent steam is supplied from the intermittent steam system 12 to the main steam system 15 and the pressure of the steam in the main steam system 15 is higher than the pressure of the supplemental steam, the steam flows from the main steam system 15 to the supplemental steam system 17. Can be prevented. In this way, the flow of supplemental steam to the main steam system 15 can be controlled with a simple configuration, which is economical.
[0011]
The steam in the steam main pipe 14 of the main steam system 15 is set to a predetermined pressure, that is, 1.6 MPa (for example, about 200 to 300 ° C.), and in order to stably operate the steam supply facility 10, for example, 1.5 It is managed in a range of about ~ 1.6 MPa (management value). The steam main pipe 14 is provided with an intermittent steam consumption system 30 including a molten steel vacuum processing apparatus (RH degassing apparatus) 29 which is an example of an intermittent steam consumption apparatus in which the steam consumption varies. This molten steel vacuum processing device 29 uses, for example, 20 to 80 t of steam per unit time intermittently (for example, for about 10 to 15 minutes), and the amount of steam used is zero when not operating. . A pipe 31 is connected to the molten steel vacuum processing device 29.
[0012]
Since the pressure adjusting valve 32 is provided on the downstream side of the pipe 31, steam adjusted to a predetermined pressure (for example, 0.7 to 0.9 MPa) by the control device can be supplied to the molten steel vacuum processing device 29. . A branch point P is provided on the upstream side of the pressure regulating valve 32 provided in the pipe 31, and steam to be supplied to the molten steel vacuum processing device 29 is provided on the front side of the branch pipe 33 branched from the branch point P. Steam accumulator 34 to store (for example, 50-100 m capacity)^Three 1) or 2 or more.
A control valve 35 capable of supplying and stopping steam at a predetermined speed gradient set in advance is provided at the upstream end of the branch point P of the pipe 31, and the main steam is passed through the control valve 35. It is connected to the steam main pipe 14 of the system 15. This makes it possible to supply and stop steam from the main steam system 15 to the intermittent steam consumption system 30.
[0013]
Further, between the branch point Q provided in the pipe 18 of the intermittent steam system 12 and the branch point P provided in the pipe 31 of the intermittent steam consumption system 30, the intermittent steam system 12 to the intermittent steam consumption system 30. A steam pipe 36 that can directly supply intermittent steam is provided. A pressure regulating valve 37 is provided in the middle of the steam pipe 36, and intermittent steam supplied from the intermittent steam system 12 is supplied to the steam intermittent consumption system 30 at a predetermined pressure by the control device via the steam pipe 36. Yes. Since the pressure of the pressure regulating valve 37 is controlled to be lower than the pressure of the control valve 27, even when intermittent steam cannot be supplied from the intermittent steam system 12 to the main steam system 15, Steam can be supplied to the intermittent steam consumption system 30. Therefore, more intermittent steam accumulated in the steam accumulator 22 of the intermittent steam system 12 can be supplied (for differential pressure).
[0014]
In this way, by supplying intermittent steam from the intermittent steam system 12 to the intermittent steam consumption system 30 via the steam pipe 36, the steam pressure in the steam main pipe 14 regardless of whether the intermittent steam consumption device 29 is in operation or not. Therefore, the disturbance of the steam main pipe 14 can be prevented, the steam supply facility 10 can be operated stably, and the workability is improved. The pressure of each steam flowing through the intermittent steam system 12, the main steam system 15, the auxiliary steam system 17, and the intermittent steam consumption system 30 is provided in the pipe 18, the steam main pipe 14, the pipe 24, and the pipe 31, respectively. It is sensed by a sensor, sent to a control device, and controlled.
[0015]
Next, a steam supply method to the intermittent steam consumption facility according to an embodiment of the present invention will be described with reference to the steam supply facility 10 and FIGS. 1 and 2.
Usually, when the measurement pressure of intermittent steam in the steam accumulator 22 of the intermittent steam system 12 is sufficiently high, that is, the total steam amount used by the plurality of steam using devices 13 and the molten steel vacuum processing device 29 is supplied from the steam accumulator 22. If possible, based on the measured pressure, the control device 27 opens the control valve 27 and the pressure regulating valve 37 respectively, and supplies intermittent steam to both the steam main pipe 14 and the steam pipe 36 (the converter blowing in FIG. 2). Smelting).
[0016]
Here, when the measurement pressure of the intermittent steam stored in the steam accumulator 22 becomes low, that is, the total steam amount used by the plurality of steam using devices 13 and the molten steel vacuum processing device 29 can be supplied from the steam accumulator 22. In the case where it disappears, for example, before the pressure of the intermittent steam in the steam accumulator 22 reaches about 1.8 MPa, the supply of intermittent steam by the control valve 27 is controlled by the control device based on the measured pressure (in FIG. 2). (Converter Blowing) At this time, intermittent steam is supplied to the steam pipe 36, but the pressure of the steam in the main steam system 15 is lower than the pressure of the supplementary steam, so that the pressure difference between the steam in the main steam system 15 and the supplementary steam. Thus, supplementary steam is supplied from the supplemental steam system 17 to the main steam system 15 via the check valve 28. Further, since the pressure of the intermittent steam flowing through the steam pipe 36 is set lower than the pressure of the intermittent steam supplied to the steam main pipe 14, the pressure of the intermittent steam is higher than the set pressure of the intermittent steam flowing through the steam pipe 36. In the meantime, the supply of intermittent steam from the intermittent steam system 12 to the steam main pipe 14 is controlled, and even when the intermittent steam system 12 is stopped, the intermittent steam is supplied from the intermittent steam system 12 to the intermittent steam consumption system 30.
[0017]
Here, the supply control of intermittent steam will be described.
The intermittent steam accumulated in the steam accumulator 22 is supplied to the steam pipe 36 at a supply flow rate Qrh (t / h), so that the stable supply to the molten steel vacuum processing device 29 is ensured and the intermittent steam in the steam accumulator 22 is provided. The flow rate gradient K preset in the steam main pipe 14 (for example, 270 t / h)² In order to supply at a supply flow rate Qgen (t / h) while increasing / decreasing by about), it is necessary to secure the amount of steam required below. The amount of steam is calculated using the amount of accumulated steam (remaining amount of intermittent steam) Vacc (t) in the steam accumulator 22. Further, the amount of accumulated steam in the steam accumulator 22 is obtained using the measured pressure in the steam accumulator 22, the enthalpy of steam, the specific hot water volume in the steam accumulator 22, and the like.
[0018]
As shown in FIG. 2, the amount of steam necessary for the supply flow rate Qgen from the steam accumulator 22 to the steam main pipe 14 to be 0 (t / h) with the gradient K is indicated by the area of the triangle X. The amount of steam that must be supplied to the molten steel vacuum processing device 29 at the supply flow rate Qrh (t / h) before the supply flow rate Qgen becomes 0 (t / h) is indicated by the area of the square Y. The area of the quadrilateral Y may be an amount of steam that is equal to or greater than the amount of steam necessary for Qrh4 and Qrh5 used in the molten steel vacuum processing apparatus 29.
Thus, the amount of steam that needs to be secured is indicated by the area surrounded by the triangle X and the quadrangle Y. This relationship is shown in equation (1).
Vacc ≧ (Qgen × Qgen / K) / 2 + Qrh × Qgen / K (1)
[0019]
Next, the formula (1) and the formula arranged for Qgen are shown in the formula (2).
Qgen ≦ −Qrh + (Qrh² +2 x K x Vacc)^1/2 ... (2)
Here, Qgen is the supply flow rate of intermittent steam from the steam accumulator 22 of the intermittent steam system 12 to the steam main pipe 14 of the main steam system 15, and Qrh is intermittent from the steam accumulator 22 of the intermittent steam system 12 to the intermittent steam consumption system 30. The steam supply flow rate, K is the flow rate gradient of intermittent steam supplied from the steam accumulator 22 of the intermittent steam system 12 to the steam main pipe 14 of the main steam system 15, and Vacc is the remaining amount of intermittent steam in the steam accumulator 22.
[0020]
If intermittent steam is supplied to the steam main pipe 14 with the maximum Qgen that satisfies the expression (2), the intermittent steam can be utilized to the maximum while guaranteeing a stable supply of intermittent steam to the molten steel vacuum processing device 29.
Here, when the pressure of the steam of the main steam system 15 is less than a predetermined pressure (1.6 MPa), the control of the control valve 27 is switched to flow control, a speed gradient is provided in the supply amount of intermittent steam, and the steam accumulator 22 accumulates. The flow rate is controlled so that the intermittent steam can be supplied to the maximum. On the other hand, when the steam pressure in the main steam system 15 is equal to or higher than the predetermined pressure, the control of the control valve 27 is switched to pressure control, the amount of intermittent steam introduced into the main steam system 15 is limited, and the intermittent flow that flows into the steam main pipe 14 is performed. The vapor pressure is controlled to 1.6 MPa. That is, the control valve 27 always controls the flow rate based on the formula (2), and performs pressure control when the demand for the steam main pipe 14 becomes smaller than Qgen.
Note that the control valve 27 is controlled by, for example, PID control, which performs control by looking at the deviation between the target value of Qgen obtained from the calculation result of equation (2) and the actual value of Qgen that is actually flowing. 27 is performed by operating continuously.
[0021]
Here, if the measured pressure of the intermittent steam in the steam accumulator 22 decreases to a pressure value that cannot be supplied to the intermittent steam consumption system 30, the supply of intermittent steam from the intermittent steam system 12 to the intermittent steam consumption system 30 is also stopped. For this reason, it is lower than the steam pressure in the steam accumulator 22 that stops the steam supply from the intermittent steam system 12 to the steam main pipe 14 (for example, about 0.1 to 0.2 MPa from the pressure value at which the control valve 27 is closed). The control valve 35 is opened by the control device at a low (measured) pressure, and steam is supplied from the steam main pipe 14 to the intermittent steam consumption system 30 at the flow rate gradient K, for example. By making this supply amount correspond to the area of the triangle Z in FIG. 2, it becomes possible to compensate for the shortage of intermittent steam that can no longer be supplied from the intermittent steam system 12.
Thereby, since the pressure disturbance of the steam main pipe 14 of the main steam system 15 is generated from one system, the pressure fluctuation can be easily controlled.
[0022]
On the other hand, the blowing of the converter is started again, the amount of intermittent steam stored in the steam accumulator 22 of the intermittent steam system 12 is sufficiently stored, and the plurality of steam using devices 13 and the molten steel vacuum processing device 29 are used. When the total amount of steam to be supplied can be supplied from the steam accumulator 22 (for example, when the pressure of the intermittent steam in the steam accumulator 22 is increased to about 1.8 MPa), the molten steel vacuum processing device 29 is stopped, as described above. Using a method opposite to the conditions, the control valve 35 is closed by the control device based on the measured pressure, and supply of intermittent steam from the intermittent steam system 12 to the intermittent steam consumption system 30 is started again via the steam pipe 36. At the same time, flow control is performed. At this time, when the pressure of the intermittent steam in the intermittent steam system 12 rises so that the steam pressure in the steam main pipe 14 becomes higher than the pressure of the supplemental steam, the check valve 28 causes the steam from the auxiliary steam system 17 to flow. The supply of auxiliary steam to the main pipe 14 is stopped, and the supply of intermittent steam from the intermittent steam system 12 to the steam main pipe 14 is resumed.
Thereby, the pressure of the steam in the steam main pipe 14 of the main steam system 15 can be controlled within the range of the management value without being affected by the presence or absence of the supply of intermittent steam.
[0023]
The present invention has been described above with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and is described in the claims. Other embodiments and modifications conceivable within the scope of the above are also included.
For example, the present invention is also applied when the steam supply method to the intermittent steam consumption facility of the present invention is configured by combining some or all of the above-described embodiments and modifications.
Moreover, in the said embodiment, the case where a fuel-fired boiler was used as a supplemental steam generator was demonstrated. However, it is also possible to provide other supplemental steam generators such as a CDQ that utilizes heat generated during the cooling of coke.
[0024]
【The invention's effect】
In the steam supply method to the steam intermittent consumption facility according to claims 1 to 4, since the supply control of the intermittent steam supplied to the main steam system is performed based on the intermittent steam amount of the intermittent steam system at the present time, Thus, for example, intermittent steam can be supplied from the intermittent steam system to the main steam system without predicting the amount of intermittent steam in the steam accumulator. Therefore, for example, the steam pressure in the steam main can be controlled to a level at which stable operation is possible without considering the effect of unforeseen due to a sudden change in schedule, and the facility can be operated stably. In addition, since more intermittent steam in the steam accumulator can be supplied, for example, it is possible to increase the amount of stored steam without changing the capacity of the steam accumulator that stores intermittent steam. For this reason, the manufacturing cost required for new equipment investment can be suppressed, and the amount of intermittent steam that cannot be stored in the steam accumulator can be reduced to the atmosphere, which is economical.
In particular, in the steam supply method to the intermittent steam consumption facility according to claim 2, the intermittent steam amount used for the intermittent steam consumption system is taken into account, and the intermittent steam amount that can be supplied to the main steam system can be easily grasped. The steam intermittent consumption device can be operated stably.
[0025]
In the steam supply method to the intermittent steam consumption equipment according to claim 3, since the supply of supplementary steam from the supplementary steam system to the main steam system is controlled by a check valve, supplementation is performed according to the steam pressure of the main steam system. It is possible to automatically supply and stop supplemental steam from the steam system. Therefore, the steam pressure in the main steam system can be controlled to a level at which stable operation is possible without being affected by the amount of intermittent steam supplied from the intermittent steam system to the main steam system. It becomes good. Further, when a large amount of intermittent steam can be supplied from the steam accumulator to the main steam system, only the intermittent steam can be supplied to the main steam system, and therefore, for example, the intermittent steam can be used without being diffused to the atmosphere, which is economical.
In the steam supply method to the steam intermittent consumption facility according to claim 4, since the intermittent steam supply method from the steam accumulator to the main steam system is changed by the control valve, the intermittent steam supplied from the steam accumulator to the main steam system, When the steam pressure in the main steam system is less than a predetermined pressure, the maximum supply is performed by flow control, and the pressure can be controlled and supplied only at the time of overpressure. Accordingly, when a large amount of intermittent steam can be supplied, intermittent steam can be supplied to the main steam system without supplying supplementary steam from the supplementary steam system to the main steam system. It is economical. Further, when the pressure of the steam in the main steam system is excessively increased, the pressure of the intermittent steam supplied to the main steam system is controlled and supplied, so that the equipment can be operated more stably and the workability is improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a steam supply facility to which a steam supply method to an intermittent steam consumption facility according to an embodiment of the present invention is applied.
FIG. 2 is an explanatory diagram of supply control to which a steam supply method for the intermittent steam consumption facility is applied.
[Explanation of symbols]
10: Steam supply equipment, 11: OG boiler (intermittent steam generator), 12: intermittent steam system, 13: steam using device, 14: steam main, 15: main steam system, 16: fuel-fired boiler (replenishing steam generation) Equipment), 17: supplementary steam system, 18: piping, 19: branch pipe, 20: diffusion valve, 21: branch pipe, 22: steam accumulator, 23: pressure reducing valve, 24: piping, 25: branch pipe, 26: steam turbine generator 27: control valve, 28: check valve, 29: molten steel vacuum processing device (steam intermittent consumption device), 30: intermittent steam consumption system, 31: piping, 32: pressure regulating valve, 33: branch pipe, 34: steam accumulator , 35: control valve, 36: steam piping, 37: pressure regulating valve

Claims

Supplying, via a control valve, intermittent steam in a steam accumulator provided in an intermittent steam system in which steam generation is intermittent to a main steam system provided with a plurality of steam using devices provided in the steam main, In the steam supply method to the steam intermittent consumption facility for supplying the intermittent steam in the steam accumulator to the steam intermittent consumption system provided with the steam intermittent consumption device provided with the steam consumption varying in the steam main,
A steam pipe capable of directly supplying the intermittent steam is provided between the intermittent steam consumption system and the intermittent steam system, and the amount of steam used by the plurality of steam use devices and the intermittent steam consumption device is set in the intermittent steam system. The supply of the intermittent steam to the steam main by the control valve is preset with the steam supply amount obtained based on the remaining amount of intermittent steam in the steam accumulator being set as a maximum . A steam supply method for intermittent steam consumption equipment, characterized by using a flow rate gradient.

In the steam supply process to claim 1 the steam intermittently consumption equipment, wherein the steam supply amount of the intermittent steam, the steam supply method to the steam intermittent consuming facility, wherein the determined al are using the following equation.
Qgen ≦ −Qrh + (Qrh ² + 2 × K × Vacc) ^1/2
Here, Qgen is the supply flow rate of the intermittent steam from the intermittent steam system to the main steam system, Qrh is the supply flow rate of the intermittent steam from the intermittent steam system to the intermittent steam consumption system, and K is the intermittent steam system. The flow rate gradient of the intermittent steam supplied to the main steam system, Vacc, is the remaining amount of intermittent steam in the steam accumulator.

3. The steam supply method to the steam intermittent consumption facility according to claim 1, wherein the main steam system is provided with a supplemental steam system capable of supplying steam to the main steam system, and the main steam is provided. A check valve is provided between the system and the supplementary steam system, the pressure value of the intermittent steam in the steam accumulator decreases, and the steam pressure of the main steam system becomes the pressure of the supplementary steam of the supplementary steam system. When the pressure drops further, the supplementary steam is supplied from the supplementary steam system to the main steam system via the check valve due to a differential pressure between the steam of the main steam system and the supplementary steam, and the steam accumulator When the pressure value of the intermittent steam of the main steam system rises and the pressure of the steam of the main steam system becomes higher than the pressure of the supplemental steam, the check valve controls the amount of the supplemental steam from the supplementary steam system to the main steam system. Serving Steam supply method to the steam intermittent consuming facility, characterized in that stop.

The steam supply method to the steam intermittent consumption facility according to any one of claims 1 to 3, wherein the control valve can perform switching between flow rate control and pressure control, and the control valve allows the main valve to be switched. When the steam pressure of the steam system is less than a predetermined pressure set in advance, the flow rate of the intermittent steam flowing to the main steam system is controlled, and when the steam pressure of the main steam system is equal to or higher than the predetermined pressure, the main steam system A steam supply method for intermittent steam consumption equipment, characterized by controlling a pressure of the intermittent steam flowing to a steam system.