JPS6115928B2 - - Google Patents
Info
- Publication number
- JPS6115928B2 JPS6115928B2 JP15997480A JP15997480A JPS6115928B2 JP S6115928 B2 JPS6115928 B2 JP S6115928B2 JP 15997480 A JP15997480 A JP 15997480A JP 15997480 A JP15997480 A JP 15997480A JP S6115928 B2 JPS6115928 B2 JP S6115928B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- furnace
- flow rate
- slab
- fuel flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000446 fuel Substances 0.000 claims description 18
- 238000010438 heat treatment Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 10
- 230000002123 temporal effect Effects 0.000 claims description 2
- 239000002893 slag Substances 0.000 claims 2
- 238000000605 extraction Methods 0.000 description 7
- 230000005855 radiation Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
- F27B9/40—Arrangements of controlling or monitoring devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D19/00—Arrangements of controlling devices
- F27D2019/0028—Regulation
- F27D2019/0034—Regulation through control of a heating quantity such as fuel, oxidant or intensity of current
- F27D2019/004—Fuel quantity
Description
この発明はスラブなどの加熱に用いられる連続
式加熱炉の制御方法に関するものである。
従来、加熱炉内のスラブの抽出温度を電子計算
機で制御するための方法としては、スラブの装入
から抽出までの炉内の谷位置におけるスラブ温度
を炉内雰囲気温度をベースとして、スラブサイ
ズ、実績在炉時間により伝熱計算して決定し、さ
らに抽出までの残在炉時間を個々のスラブの抽出
スケジユールより予測して求め抽出目標温度にす
るために必要な炉内雰囲気温度を逆算して炉内雰
囲気温度が上記設定値になるように燃料流量を制
御する方方法がとられている。
しかしながら、上記のように炉内雰囲気温度を
ベースにして伝熱計算をし、又雰囲気温度が目標
温度になるように燃料流量を制御する方法には、
次のような欠点がある。
第１図に示すように加熱炉１の各制御帯に付つ
ている炉温測定用の温度計２は１〜２ケ所であり
これより伝熱計算に必要となる温度分布を得るた
めには第２図に示すように数少ない測定値（図中
×印）より推定するため非常に精度の悪いものと
なり、炉の状況を正確に把握する事が困難であ
る。
温度計２はバーナー３よりの火炎の影響を受け
やすく炉雰囲気温度を必ずしも正確に示してはい
ない。
またスラブを抽出目標温度にするために必要な
炉内温度を逆算して求めて設定しているが実際炉
温はすぐにその温度にはならず時間遅れが生じ、
スラブの抽出温度の精度が悪くなる。
この発明は、上記のような従来方法における欠
点を除去するためになされたもので投入燃料流
量、投入空気流量を与えて炉内温度分布の時間変
化を計算し、この炉温を用いて、現時刻および将
来のスラブ温度を計算しスラブの予測値と目標値
がある設定値以下になるよう投入燃料の流量予測
を行い、これを目標値として流量制御を行い各ス
ラブを目標昇温曲線に沿つて加熱するように制御
することにより、精度の良い加熱制御方法を提供
することを目的としものである。
以下、この発明の一実施例における制御方法に
ついて詳細に説明する。第３図は連続式加熱炉を
モデル化したものの例である。加熱炉１の炉温分
布は以下の手順で決定される。第３図に示すよう
に、加熱炉１を炉長方向にｎ個に分割する。各分
割されたメツシユについておのおの熱いバランス
方程式をたてると次式になる。
C1αＴｇ，ｉ／ｄｔ ……炉内の温度変化
＝Q1 ……燃料空気の顕熱
＋Hg・Wi ……燃料発熱量
＋Gi＋１・Cpg・Tgi＋１
……上流よりの排ガス熱量
−Gi・Cpg・Tg・ｉ ……下流への排ガス熱量
……他のガスメツシユよりのふく射
……炉壁よりのふく射
……スラブよりのふく射
＋C2，（TWi−Tg・ｉ） ……炉壁との対流
＋C3，（Ts・ｉ−Tg・ｉ）
……スラブとの対流
（ｉ＝１……ｎ） ……１
ここで、Tg、Tsはそれぞれ炉内温度、炉壁温
度、スラブ温度、ｔは時間、Qiはｉ番目のメツ
シユへの燃料、空気の顕熱であり次式で表わせ
る。
Qi＝Wi・CPf・Tf＋Ai・Cpa・Ta ２
Wi，Aiはｉメツシユへの燃料および空気流
量、Cpf，Cpaは燃料および空気の比熱、Tf，Ta
は燃料および空気の温度である。
又、Hhgは燃料の単位流量当りの発熱量、Giは
ｉメツシユの排ガス流量であり次式で表わせる。
Goはこの燃料の単位流量当りの理論排ガス
量、Aoは理論空気量、μは空気過剰係数であ
る。
μ＝Ao・Vi／Ai ４
K1ij，K2ik，K3iはそれぞれふく射交換係数
であり、C1，C2，C3は定数である。
投入燃料および空気流量が与えられれば、１ス
テツプ前の計算結果の炉内温度、スラブ温度を境
界条件にして式１は次式の様な形に変形される。
（ｉ＝１……ｎ）
これは、ｎπ連立の非線形の微分方程式である
が、１ステツプ前の計算結果である炉内温度分布
を出発値とし、時間に関して離散化し、Newton
法等を用いて収束させれば新らしい炉内温度分布
を決定することが可能となる。
さらに詳しく説明するなら、先ず、式(5)の非線
形微分方程式を時間に関して離散化する。離散化
手法は次の中心差分を用いる。
式(5)中の
The present invention relates to a method of controlling a continuous heating furnace used for heating slabs and the like. Conventionally, as a method for controlling the extraction temperature of a slab in a heating furnace using an electronic computer, the slab temperature at the valley position in the furnace from the time of slab charging to extraction is determined based on the furnace atmosphere temperature, and the slab size, Determine by calculating the heat transfer based on the actual furnace time, and further calculate the remaining furnace time until extraction by predicting from the extraction schedule of each slab and back-calculating the furnace atmosphere temperature required to reach the extraction target temperature. A method is used to control the fuel flow rate so that the temperature of the atmosphere inside the furnace reaches the above-mentioned set value. However, as mentioned above, the method of calculating heat transfer based on the furnace atmosphere temperature and controlling the fuel flow rate so that the atmosphere temperature becomes the target temperature,
It has the following drawbacks: As shown in Figure 1, there are one or two thermometers 2 attached to each control zone of the heating furnace 1 to measure the furnace temperature. As shown in Figure 2, since the estimation is based on a small number of measured values (marked with an x in the figure), the accuracy is extremely low, making it difficult to accurately grasp the situation of the furnace. The thermometer 2 is easily influenced by the flame from the burner 3 and does not necessarily accurately indicate the furnace atmosphere temperature. In addition, the furnace temperature necessary to bring the slab to the extraction target temperature is calculated backwards and set, but the actual furnace temperature does not reach that temperature immediately and there is a time delay.
The accuracy of the slab extraction temperature deteriorates. This invention was made in order to eliminate the drawbacks of the conventional method as described above, and calculates the temporal change in the temperature distribution in the furnace by giving the input fuel flow rate and the input air flow rate, and uses this furnace temperature to calculate the current Calculate the time and future slab temperature, predict the flow rate of the input fuel so that the predicted slab value and target value are below a certain set value, use this as the target value to control the flow rate, and move each slab along the target temperature rise curve. The object of the present invention is to provide a highly accurate heating control method by controlling the heating to occur. Hereinafter, a control method in an embodiment of the present invention will be explained in detail. Figure 3 is an example of a model of a continuous heating furnace. The furnace temperature distribution of the heating furnace 1 is determined by the following procedure. As shown in FIG. 3, the heating furnace 1 is divided into n pieces in the furnace length direction. If we create a hot balance equation for each divided mesh, we get the following equation. C 1 αTg,i/dt ...Temperature change inside the furnace =Q 1 ...sensible heat of fuel air +Hg・Wi ...fuel calorific value +Gi+1・Cpg・Tgi+1
...Calorific value of exhaust gas from upstream -Gi・Cpg・Tg・i ...Calorific value of exhaust gas downstream ... Emissions from other gas sources ... Radiation from the furnace wall ... Radiation from the slab +C 2 , (TWi-Tg・i) ... Convection with the furnace wall +C 3 , (Ts・i−Tg・i)
...Convection with the slab (i=1...n) ...1 Here, Tg and Ts are the furnace temperature, furnace wall temperature, and slab temperature, respectively, t is time, Qi is the fuel to the i-th mesh, It is the sensible heat of air and can be expressed by the following formula. Qi=Wi・CPf・Tf+Ai・Cpa・Ta 2 Wi, Ai are fuel and air flow rates to i mesh, Cpf, Cpa are specific heats of fuel and air, Tf, Ta
are the fuel and air temperatures. Further, Hhg is the calorific value per unit flow rate of fuel, and Gi is the exhaust gas flow rate of the i-mesh, which can be expressed by the following equation. Go is the theoretical exhaust gas amount per unit flow rate of this fuel, Ao is the theoretical air amount, and μ is the excess air coefficient. μ=Ao·Vi/Ai 4 K 1 ij, K 2 ik, and K 3 i are radiation exchange coefficients, respectively, and C 1 , C 2 , and C 3 are constants. If the input fuel and air flow rate are given, equation 1 can be transformed into the following equation using the furnace temperature and slab temperature calculated one step before as boundary conditions. (i=1...n) This is a nπ simultaneous nonlinear differential equation, but the starting value is the temperature distribution in the furnace, which is the calculation result of one step before, and is discretized with respect to time.
If convergence is achieved using a method, etc., it becomes possible to determine a new temperature distribution within the reactor. To explain in more detail, first, the nonlinear differential equation of equation (5) is discretized with respect to time. The discretization method uses the following central difference. In formula (5)
【表】
〓……(6)
(Tg.iＮ−Tg.iＯ)[Table] 〓……(6)
(Tg.i N −Tg.i O )
Claims (1)
燃料流量および投入空気流量を検知し、投入燃料
流量および投入空気流量から炉温分布の時間変化
を決定する機能を用いて現時刻までの炉温分布を
決定し、この炉温分布を用いて現時刻のスラブ温
度を求め、このスラブ温度と任意に設定した投入
燃料流量を基に上記炉温決定機能で将来の炉温変
動を予測し、この予測炉温を用いて予測スラグ温
度を決定し、予測スラグ温度と目標スラブ温度の
偏差がある設定値以下になるように投入燃料流量
を決定し、これを目標値として投入燃料の流量制
御を行うようにしたことを特徴とする連続式加熱
炉の制御方法。1. Detects the input fuel flow rate and input air flow rate at any given time in each control zone of the continuous heating furnace, and uses the function to determine the temporal change in the furnace temperature distribution from the input fuel flow rate and input air flow rate. Determine the furnace temperature distribution, use this furnace temperature distribution to find the current slab temperature, and use the above furnace temperature determination function to predict future furnace temperature fluctuations based on this slab temperature and the arbitrarily set input fuel flow rate. , determine the predicted slag temperature using this predicted furnace temperature, determine the input fuel flow rate so that the deviation between the predicted slag temperature and the target slab temperature is below a certain set value, and use this as the target value to control the input fuel flow rate. 1. A method for controlling a continuous heating furnace, characterized in that:
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15997480A JPS5782427A (en) | 1980-11-12 | 1980-11-12 | Control method for continuous type heating furnace |
| US06/311,331 US4394121A (en) | 1980-11-08 | 1981-10-14 | Method of controlling continuous reheating furnace |
| DE3142992A DE3142992C3 (en) | 1980-11-08 | 1981-10-29 | Method and device for heat control of a continuous furnace |
| BR8107230A BR8107230A (en) | 1980-11-08 | 1981-11-06 | PROCESS FOR CONTROL OF A CONTINUOUS REHEATING OVEN |
| MX189993A MX161415A (en) | 1980-11-08 | 1981-11-06 | METHOD FOR CONTROLLING A CONTINUOUS REHEAT OVEN |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15997480A JPS5782427A (en) | 1980-11-12 | 1980-11-12 | Control method for continuous type heating furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5782427A JPS5782427A (en) | 1982-05-22 |
| JPS6115928B2 true JPS6115928B2 (en) | 1986-04-26 |
Family
ID=15705234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15997480A Granted JPS5782427A (en) | 1980-11-08 | 1980-11-12 | Control method for continuous type heating furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5782427A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0228668Y2 (en) * | 1986-03-26 | 1990-08-01 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113218197B (en) * | 2021-05-12 | 2022-11-25 | 莱芜钢铁集团电子有限公司 | Sintering end point consistency control system and method |
-
1980
- 1980-11-12 JP JP15997480A patent/JPS5782427A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0228668Y2 (en) * | 1986-03-26 | 1990-08-01 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5782427A (en) | 1982-05-22 |
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