JPH01320514A - Control method in vapor distribution system - Google Patents

Abstract

PURPOSE:To attain labor saving, the reduction of vapor loss, and the stable operation of a vapor system by selecting a control mode decided in advance fitting in each monitoring point of the vapor system, a load on a vapor supply side, and the status of a user side, and performing automatic adjustment on the exit vapor flow rate of a supply facility. CONSTITUTION:The monitoring points (N1-N3) of vapor pressure, etc., are provided at pipes to plural vapor using facilities (21-23) from the vapor supply facility such as an accumulator 11, a back pressure turbine 12, and a blast boiler 13, etc. A controller 3 compares pressure values from those monitoring points with a reference value set separately, and decides the control mode based on a pressure trend and the use schedule information of the vapor using facility, and also, and the flow rate preset value of each supply facility is found by a prescribed equation by judging the status of a distribution system from the load condition of the supply facility and the fluctuation of a quantity in use at the vapor using facility side, thereby, the vapor exit flow rate of each supply facility is controlled and the fluctuation of pressure at each monitoring point can be controlled within tolerance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to an accumulator (ACC) by steam balance including steam usage fluctuations of steam usage equipment.

The present invention relates to a control method for automatically controlling the flow rate of each steam outlet by calculating the flow rate setting value of each steam supply equipment such as a back pressure turbine and a temperature reduction and pressure reduction device.

[Conventional technology]

Conventionally, control of such steam system systems has been performed exclusively manually. In other words, pressure monitoring points are set up to serve as a guideline for operation, and operators can visually check each pressure monitoring point to check the steam usage fluctuations of each steam-using facility, the load status of the back pressure turbine on the steam supply side, the temperature reduction and pressure reduction equipment, and the accumulator. The back pressure turbine, temperature reduction and pressure reduction device, and outlet flow rate of the Achiemulator are all manually adjusted based on the pressure state of the system.

In other words, if the pressure at each pressure monitoring point is all lower than the standard pressure, the steam flow rate on the steam provider side is increased accordingly, and conversely, if all the pressure monitoring points are higher than the standard pressure, the steam flow rate on the provider side is decreased. let

In addition, if the pressure is above the upper limit or below the upper or lower limit at each pressure monitoring point, the steam flow rate on the provider side is manually adjusted according to each pressure, and information on the steam usage schedule of the steam usage equipment is provided. Even when information on the start and end of steam usage is given, the operator makes all decisions and manually adjusts the steam flow rate on the provider side.

[Problem to be solved by the invention]

As described above, judgments and operations that have conventionally been performed manually by an operator differ depending on individual differences and experience of the operator. Therefore, the following problems arise in manual operation.

(b) Increased burden on operators Steam usage of steam-using equipment is not always carried out as planned. Therefore, if there is usage schedule information or if the pressure at the pressure monitoring point is predicted to exceed the upper and lower limits, a constant monitoring operation is required. Furthermore, it is difficult to quantitatively capture the amount of operation, and monitoring operations require considerable skill.

(b) Steam Loss Problem Since the judgment of operation differs depending on the operator, if there is an inconvenience in operation, the pressure at each pressure monitoring point may exceed the allowable range, or steam may not be stably supplied to each steam-using equipment. Therefore, in order to avoid these, for example, it is necessary to operate with a certain amount of margin for the control target value. However, operating with this margin in mind is not optimal, and if there is excess steam, it will be dissipated, resulting in steam loss.

Therefore, in order to solve the above problems, this invention
The operator's monitoring operation is automated, and the control mode is automatically selected according to the load status of each pressure monitoring point and the steam supply side, as well as the steam usage status of the steam usage equipment, and the accumulator and back pressure are adjusted according to the control mode. By automatically adjusting the outlet steam flow rate of each steam supply equipment, including the turbine and temperature reduction and pressure reduction equipment, we aim to (a) save labor through automation, (b) reduce steam loss through automation, and (c) ensure stable operation of the steam system. The purpose is to

[Means to solve the problem]

There are fewer piping systems that supply steam from individual steam supply equipment, including accumulators, back pressure turbines, and temperature reduction and depressurization equipment, to multiple steam usage equipment (a pressure monitoring point is installed at one location to monitor the steam pressure). Comparison result of point pressure with separately set reference pressure.

The control mode is determined based on the increase/decrease trend in the integrated amount of pressure time series data over a certain period of time (pressure - current) and the steam usage schedule information of the steam usage equipment, and the load conditions of each steam supply equipment and the steam usage equipment side are determined. The status of the steam distribution system is judged from the fluctuations in the amount of steam used, the flow rate setting value of each steam supply equipment is determined from a predetermined calculation formula, the steam outlet flow rate of each steam supply equipment is controlled by the calculated setting value, and each Control pressure fluctuations at monitoring point pressures within an acceptable range.

[Effect]

The control mode is determined by monitoring the current pressure, the pressure trend up to the present, and the steam usage status from each pressure monitoring point, and this control mode has the following functions.

(1) Mode when the pressure at each pressure monitoring point is below the reference pressure and the pressure trend is decreasing (2) When the pressure at each pressure monitoring point is above the reference pressure and the pressure trend is increasing Mode (3) Mode when steam usage schedule information of steam-using equipment is given (4) Mode when steam is being used by steam-using equipment In mode (1), the pressure at the pressure monitoring point is increased. In order to
If the load on the depressurizer can be increased, each outlet flow rate setting is increased to bring the pressure at each pressure monitoring point to match the reference pressure.

In mode (2), in order to reduce the pressure at each pressure monitoring point, the load status of the ACC outlet pressure, back pressure turbine, and temperature reduction and pressure reduction device is determined, and when the ACC outlet pressure is low (back pressure turbine, temperature reduction and pressure reduction device) If the load on the device can be reduced, each outlet flow set point is reduced to bring the pressure at each pressure monitoring point to match the reference pressure.

In mode (3), in order to prevent the pressure at each pressure monitoring point from decreasing due to the use of steam in the steam-using equipment, the load status of the ACC outlet pressure, back pressure turbine, and temperature reduction and pressure reduction device is judged, and the back pressure turbine and temperature reduction device are checked. If the load on the pressure reducer can be increased, the respective outlet flow set point is increased to pre-increase the pressure at each pressure monitoring point.

If the ACC pressure is low, reduce the ACC outlet flow set point. The pressure at each pressure monitoring point is increased by the back pressure turbine and the outlet flow rate of the decompressor.

In mode (4), in order to prevent the pressure at each pressure monitoring point from decreasing due to steam usage in the steam usage equipment, the ACC outlet pressure,
Determine the load status of the back pressure turbine and temperature reducing device, and if it is possible to increase the load on the back pressure turbine and temperature reducing device, increase the outlet flow rate setting value of each to prevent the pressure from decreasing at each pressure monitoring point. , maintain the reference pressure. If the ACC pressure is high, the AC
Increase the C outlet flow rate setpoint. ACC and back pressure turbine.

The pressure at each pressure monitoring point is kept constant at the standard pressure using the outlet flow rate of the decompression device.

By determining the state of the steam system and automatically selecting one of the four control modes listed below, A
The pressure of the steam system is kept stable by controlling the outlet of the CC, backpressure turbine, and temperature reduction/decompression device.
Enables a stable supply of steam to each steam-using facility.

〔Example〕

FIG. 1 is a schematic diagram showing the entire blunt to which the present invention is applied.

In this case, the Akiemulator (ACC) 11 on the steam supply side
, a back pressure turbine 12, a blower boiler (DPT) 13 as a temperature and pressure reducing device, and a pressure monitoring point N.

-N, and steam using equipment 21-23 are arranged as shown in the figure. In order to stabilize this system and stably supply steam to each steam-using facility, the control device 3 performs control as follows.

FIG. 2 (Part 1) to FIG. 2 (Part 9) are flowchart 1 for explaining the operation of the control device.

First, arithmetic expressions for determining the outlet flow rate settings of the back pressure turbine and the temperature reduction and pressure reduction device will be explained.

A differential equation representing pressure fluctuations in a piping system is generally expressed as the following equation.

P: Pressure (kg/m3) L: Time (see) V: Specific volume (m/myo) ■: Volume of piping (+f) () 77 o'clock (T/H)) ΔW:
Steam amount set value change amount α Δt However, ΔP=PM Pp (Current time pressure PM and 20-minute formula (2
), the set value S■ is given by the following formula.

SV (k)=SV (k-1)-1-ΔW ---
---(3) (k=1.2....,N) In this way, the outlet flow rate setting value of each steam supply equipment is determined. The operation in each mode will be explained below.

(1) When the pressure at each pressure monitoring point is below the standard and the pressure trend is decreasing: P+(k): Pressure at each pressure monitoring point (ata: absolute pressure (kg/cmt)) (i=1.2.3・・－：
Considering various quantities such as PB,: Pressure at each pressure monitoring point (ATA), ΔPB,: Deviation pressure at each pressure monitoring point (ATA), data for the past 20 minutes (1 minute) from the current time is calculated. 20 pieces of data for each), Pi(k)≦PBE1ΔP
B.

(k=1.2...., 20) ......(4) Σ(1'1(k)-Pi (k-1)) <O (pressure trend)... When equations (4) and (5) expressed as in (5) hold true at the same time, a set value is calculated using the above-mentioned arithmetic equation, and the back pressure turbine, temperature reduction and pressure reduction device, A
CC outlet steam flow rate operation end is controlled and each monitoring pressure point pressure P
Direct (k) is PB, -Δr'Bmu ≦P5(k) ≦PB, + ΔP
B.

Make it so that Note that FIG. 2 (part 1) shows the operation at this time.

(2) When the pressure at each pressure monitoring point is above the standard and the pressure trend is increasing, P i (k)≧PB+ 1ΔPB.

(k=1.2....,) ......(6) ......(7) If the above equations (6) and (7) hold simultaneously, the above calculation formula A set value is calculated from the set value, and the back pressure turbine, temperature reduction and pressure reducing device, and ACC outlet steam flow rate operating end are controlled to follow this set value, and each monitored pressure point pressure Pi (k) is set to PB! −ΔPBt ≦Pt(k) ≦PB50Δr'B
Be direct. The operation at this time is shown in Figure 2 (Part 2).
).

(3) When steam usage schedule information of steam usage equipment is given TBN\LMT\(1)>TBN...
(8) TBN\LMT\(1): Back pressure turbine steam flow rate upper limit TBN: Back pressure turbine steam flow rate Pacc(k)≦PBacc-ΔPBAcc
......(9) PAcc (k): A CC outlet pressure (k = 1.2..., 20') PBAcc
: A CC reference pressure ΔPBAcc : A CC reference pressure deviation DPT￥L
MT¥>DPT ・・・・・・(10)D
PT￥LM'r: upper limit of steam flow rate in temperature and pressure reduction device DPT: steam flow rate in temperature and pressure reduction device When equations (8), (9), and (10) hold simultaneously, the set value is calculated using the above-mentioned calculation formula. Then, to follow this set value, the back pressure turbine, temperature reduction and pressure reduction device,
Control the ACC outlet steam flow operating end to increase each pressure monitoring pressure in advance. FIG. 2 (part 3) shows this operation.

(4) When steam is being used in steam-using equipment In this case, the load condition of the back pressure turbine and *temperature decompression device is expressed by the equation (8) above.
Judging by (10), PAcc(k)≧PBAcc+Δ
PBAcc - If (11) holds, then
A set value is calculated using the above-mentioned formula, and the back pressure turbine, temperature reduction and pressure reducing device, and ACC outlet steam flow control terminal are controlled to follow this set value, and each monitoring pressure due to steam usage of the steam usage equipment is controlled. Try to prevent a drop in point pressure. The operation is shown in FIG. 2 (part 4).

(5) When the pressure monitoring point N is below the upper and lower limits, PLL, ≧P
, (k) ......(12
)P+(k): Pressure at pressure monitoring point Nl (k=1.2.・
..., 20) PLL, : If the pressure lower limit value of pressure monitoring point N1 is established and the above equations (8) and (10) are established, then the set value is calculated using the above-mentioned arithmetic formula, and this set value is Back pressure turbine, temperature reduction and pressure reduction device to follow.

The outlet steam flow rate operating end is controlled, and the pressure at the pressure monitoring point N is PB, -ΔPBI < PI (k) < FBI+Δ
P.B.

Make it so that This operation is shown in FIG. 2 (part 5).

(6) When pressure monitoring point Nt or pressure monitoring point N is below the upper and lower limits, PLL, ≧Pz(k)...
・(13) pi, t, z: Pressure lower limit value PI (k) of pressure monitoring point N2: Pressure (k・1,
2. ..., 20) PLLs≧Ps(k)
......(14) Ps(k): Pressure at pressure monitoring point N3 (k・1, 2..., 20) PLL3
: Pressure lower limit value formula (13) at pressure monitoring point N, (
If either one of (14) holds true and formula (9) also holds, the ACC outlet steam flow rate setting value is calculated from the previous calculation formula, and at this time, formula (8).

If (10) holds true, the back pressure turbine, temperature reduction and pressure reduction device, each outlet steam flow rate setting value is calculated using the above calculation formula, and the back pressure turbine, temperature reduction and pressure reduction device,
The ACC outlet steam flow rate operating end is controlled so that PB2-ΔPBz<Pg(k)≦PBX+ΔPB.

or PB, -ΔPBff<r'x(k) <PB:l+ΔP
Make it so that it is lh. The operation at this time is shown in FIG. 2 (part 6).

(7) When pressure monitoring point N is above the upper limit, PHH, < P
,(k)...(15)P
HH,: Pressure upper limit Pl(k) of pressure monitoring point N: When pressure (k・1, 2..., 20) of pressure monitoring point N holds true, TBN\I, MT\(2) )＜TBN・・・・・・
(16) TBN\LMT\(2): Lower limit of back pressure turbine steam flow rate TBN: Back pressure turbine steam iJt amount DPT\LMT\(2) <DI"T...
(17) DPT￥LMT￥(2) Lower limit value of steam flow rate for two temperature reduction and decompression devices DPTs Temperature and pressure reduction device steam flow rate When (16) and (17) hold simultaneously, calculate the set value using the above calculation formula, The back pressure turbine, temperature reduction and pressure reduction device, and ACC output steam flow rate control end are controlled to follow this set value, and the pressure monitoring point N is set.

the pressure of PB, -ΔPRI<PI(k)≦PB, +ΔPB.

Make it so that The operation at this time is shown in Figure 2 (Part 7).
Shown below.

(8) When pressure monitoring point N2 or pressure amount viewpoint N3 is above the upper limit value, PHHt≦P, (k)...
... (18) PHH,: Upper pressure upper limit value Pz (k) of pressure monitoring point N2: Pressure of pressure monitoring point N2 (k = 1.2...
・, 20) P H113< P3(k)
......(19) PHH,: Pressure at pressure monitoring point N3"-"-limit value Ps(k): Pressure at pressure monitoring point N, (
k・1,2. ..., 20) If formula (11) holds when either formula (18) or (19) holds true, the ACC outlet steam flow rate set value is calculated from the previous calculation formula, and at this time, formula ( If 16) and (17) hold true, calculate the steam flow rate settings at the outlets of the back pressure turbine and temperature reducing device from the above equation, and set the back pressure turbine and temperature reducing device to follow these set values. , controls the ACC outlet steam flow rate operating end, PBz-ΔPBz≦Pz(k)≦PB, +ΔPB2 or PB3-ΔPI(, ≦P 3 (k)≦PB, +ΔPR
Make it 3. FIG. 2 (Part 8) shows the operation at this time. In addition, FIG. 2 (Part 9) shows the destinations of Parts 1 to 8 of the same figure.

FIG. 3 shows a specific example of control operation.

That is, assuming that the usage flow rate changes on the steam usage equipment 21, 22, and 23 sides are shown as shown in (a), (b), and (c), respectively, ACCII.

Back pressure turbine 12. Each outlet flow rate setting value of DPT13 is shown as (d), (e), and (f) in the same figure, and the pressure changes at pressure monitoring points N+, Nz, and N3 are shown in () in the same figure, respectively.
), (ch), (su), and ACCI
The outlet pressure change and flow rate change of I are shown in the same figure (N).
, (ru), and it can be seen that especially the pressure fluctuation is suppressed within the permissible range.

〔Effect of the invention〕

According to this invention, the following effects can be expected.

l) Labor saving through automation ■ Operation of back pressure turbine outlet flow rate ■ Operation of temperature reduction and decompression device outlet flow rate ■ Operation of ACC outlet flow cover (operations that were previously performed manually can be omitted as they are automated) 2) Improved control accuracy A plant model is used to calculate the set value based on the pressure state of the steam system and the load state on the steam supply side, and the steam outlet flow rate is controlled using the set value. This enables more precise control than manual control.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the entire plant to which this invention is applied, Fig. 2 (parts 1 to 9) is a flowchart for explaining control operations according to the invention, and Fig. 3 is a specific example of control operations. It is a time chart for explaining. Description of symbols 11...Accumulator (ACC), 12...Back pressure turbine, 13...Blast boiler (DPT), 21-2
3...Steam usage equipment, N, -N,...Pressure monitoring point. Agent Patent Attorney Akio Namiki Agent Patent Attorney Kiyohi Matsuzaki 2 drawings (Otsu No. 1) Uri 2 drawings (Mi ■ 2)! Figure 2 (Otsu no 5) Figure 2 (Zo ■4) Figure 2 (Zo ■5) 12 Figure (Mi016) 1F 2 vA (Kcn7) Figure 2 (!O8) Prisoner 2 Figure (Otsu no 9) @3 Figure T/H

Claims (1)

[Claims] A pressure monitoring point for monitoring the steam pressure is provided at least at one location on the piping that supplies steam from each steam supply facility including an accumulator, a back pressure turbine, and a temperature reduction/decompression device to a plurality of steam using facilities, and the pressure at the monitoring point is The control mode is determined based on the comparison result with a separately set standard pressure, the increase/decrease trend in the cumulative amount of pressure time series data over a certain period of time (pressure trend), and the steam usage schedule information of the steam usage equipment. Judging the status of the steam distribution system from the load conditions of the supply equipment and fluctuations in steam usage on the steam usage equipment side, the flow rate setting value of each steam supply equipment is determined from a predetermined calculation formula,
A control method for a steam distribution system, characterized in that the steam outlet flow rate of each steam supply facility is controlled using the calculated set value, and pressure fluctuations at each monitoring point pressure are controlled within an allowable range.