JPH07167405A - Enriched blow controlling method for boiler - Google Patents

Abstract

PURPOSE:To provide a method for controlling to correct an enriched blow rate corresponding to a change of an electric conductivity of water to be supplied in a boiler for automatically controlling enrichment based on a preset enriched blow rate. CONSTITUTION:A boiler 1 switches an enriched blow valve 7 based on a preset enriched blow rate, and automatically controls an enrichment rate of a boiler water. The boiler 1 further presets an operating time until an electric conductivity of the water becomes substantially constant, calculates a suitable enriched blow rate by using following formula (1) if an electric conductivity of the water after the operating time is elapsed and a predetermined electric conductivity of the water is different, corrects the enriched blow rate to the value, and controls it. In the formula, E: electric conductivity of the boiler water, E=E0/alpha...(1) E0: electric conductivity of supplied water, and alpha: blow rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a concentrated blow of a boiler.

[0002]

2. Description of the Related Art Generally, in a boiler, if the boiler water in the boiler is continuously heated at a high temperature for a long time, it is concentrated and injected in proportion to the amount of steam generated and used. The residual density such as chemical concentration also becomes large, and as a result, it becomes difficult to maintain the high dryness of the generated steam.

In order to avoid this situation, conventionally, a strainer has a strainer equipped with a concentration blow valve that normally closes the valve in the downcomer pipe of the separator of the boiler and discharges the can water from the blow pipe to the outside when the valve is opened. Installed through the concentration blow valve and the control unit is installed in the circuit connecting the concentration blow valve and the electrical conductivity measurement sensor installed in the downstream of the downcomer, and the electrical conductivity measurement sensor is used to concentrate the can water in the downstream of the downcomer. The change of the electric conductivity proportional to the degree is detected, and when the electric conductivity exceeds the specified value, the control unit is controlled by the control signal generated from the electric conductivity measuring sensor,
The concentrated blow valve is opened to discharge the highly concentrated canned water to the outside, and at the same time, as the highly concentrated canned water is discharged, it is diluted with new canned water that is automatically replenished into the can via the water supply device. When the concentration of the whole canned water decreases and the electric conductivity of the canned water falls below a specified value, the blow operation signal disappears and the concentrated blow valve is automatically closed by attaching it to a boiler. We are trying to maintain high dryness of the generated steam.

However, in the conventional automatic concentrating blower attached to the boiler, the electric conductivity of the water to be supplied greatly changes depending on its temperature, so that it deviates from the reference value depending on the usage condition of the boiler and its pressure. By the way, there are cases that are working. In addition, when performing maintenance on the boiler, the ratio of the blow rate to the water supply rate is measured to check whether the current electrical conductivity (sensor) setting is correct. At that time, the current situation is that the proper value is obtained by re-setting many times.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a control system for automatically controlling the concentration of canned water based on a preset concentration blow rate. It is an object of the present invention to provide a boiler concentration blow control method for automatically controlling the concentration of canned water by correcting a preset concentration blow rate in response to changes in the above.

[0006]

In view of the above-mentioned problems, the present invention provides a boiler in which the concentration blow valve is opened / closed and the concentration of canned water is automatically controlled based on a preset concentration blow rate. When the operating time until the electric conductivity of the canned water becomes almost constant is preset, and the electric conductivity of the canned water at the time when the operating time has passed and the electric conductivity of the predetermined canned water are different, It is characterized by calculating an appropriate concentration blow rate using the following formula and correcting the concentration blow rate to that value, or based on a preset concentration blow rate, opening and closing the concentration blow valve to In a boiler that automatically controls the enrichment, measure the electrical conductivity of the water to be supplied to the boiler, and if the measured electrical conductivity of the feed water and the electrical conductivity of the prescribed feed water are different, use the following formula Calculates the specific concentration blow rate and the value It is characterized by modifying the blowdown rate. E: electric conductivity of canned water E = E ₀ / α ... E ₀ : electric conductivity of feed water α: blow ratio

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of claim 1 of the present invention will be described below in detail with reference to the drawings. The embodiment shown in the drawings is
As an example, it is a case where the concentration blow control method according to the present invention is applied to a multi-tube once-through boiler.

As shown in FIG. 1, at the bottom of the boiler 1,
A water supply pipe 2 of a water supply device (not shown) including a check valve, a filter, a chemical injection device, etc. is connected and connected. The other end of the water supply pipe 2 is connected to a water source such as a water supply or a well, and is connected to a water supply pump P.
The water of the water source is filtered and the water is supplied into the can of the boiler 1 as the water for the medicinal can in which the medicinal solution is injected. Further, as shown in FIG. 1, a separator 3 for separating steam of the generated steam into one side of the boiler 1 communicates with the upper and lower parts of the boiler 1 via a steam communication pipe 4 and a downfall pipe 5, as shown in FIG. A blow pipe 8 having an electric conductivity measuring sensor 6 and an electromagnetic open / close type concentration blow valve 7 is connected to the lower part of the downcomer pipe 5 so as to communicate therewith.

The operation and shutdown of this type of boiler 1 are usually
Based on a load condition, a combustion controller (not shown) controls the pressure based on a signal from a pressure detector 9 that detects the internal pressure of the boiler 1. That is, the combustion is stopped when the internal pressure of the can exceeds a preset pressure value, and the combustion is started when the internal pressure falls below the preset pressure value. A combustion detection sensor 10 that detects combustion in the boiler 1 is set in the burner 16 of the boiler 1, and the combustion state and combustion time in the boiler 1 are measured. That is, the pressure detector 9 and the combustion detection sensor 10 form a detection unit that controls the operating condition of the boiler 1.

A controller 1 for controlling the opening and closing of the concentration blow valve 7.
1 has a calculation function with a built-in microcomputer, for example, and based on detection signals from detection means such as the pressure detector 9 and the combustion detection sensor 10 and a preset blow rate, the concentration blow valve 7
Is calculated, the time for intermittently opening and closing the concentration blow valve 7 is determined, and the signal is output to the concentration blow valve 7. Therefore, this controller 11 is a pressure detector 9 that constitutes the detecting means of the boiler 1.
It is connected to the combustion detection sensor 10 via communication lines 12 and 13, respectively, and is connected to the concentration blow valve 7 to communication line 14 and the electrical conductivity measuring sensor 6 to communication line 15 respectively.

Generally, the blow rate (ratio between the blow rate and the water supply rate) is set by analyzing the water quality (pH, etc.) of the raw water (well water, tap water) to be supplied in advance, and the necessary cleaning agent. It is decided by taking into consideration the input amount, etc., but generally 10% to 15%
It will be about. The water supply amount can be calculated from the water supply time, but the change in the capacity of the water supply pump P and the boiler 1
Since the water supply amount per unit time may fluctuate due to the pressure fluctuation, etc., the water supply amount was calculated by the evaporation amount x the combustion time, and the blow rate was defined as the ratio of the blow amount and the evaporation amount x the combustion time. That is, it is more accurate to calculate the blow amount with detection signals from the pressure detector 9 and the combustion detection sensor 10 of the boiler 1. This is because the evaporation amount of the boiler 1 is determined by the rating.

According to the control system for automatically controlling the enrichment having the above-mentioned configuration, the pressure detector 9, the combustion detection sensor 10, and the combustion detection sensor 10 can detect the internal pressure of the can, the combustion state of the burner, the combustion time, etc. while the boiler 1 is in operation. The detection means such as the electric conductivity measuring sensor 6 always detects and outputs the detection signal to the controller 11. The controller 11 receiving the output signal calculates the opening / closing timing of the concentration blow valve 7 based on the preset blow rate and its detection signal, and determines the time for intermittently opening / closing the concentration blow valve 7. The concentration blow valve 7 is automatically opened and closed.

In the system for automatically controlling the concentration of canned water having the above-described structure, the method for controlling concentration blow of the present invention provides a time period from the start of the operation of the boiler 1 until the electric conductivity of the canned water becomes substantially constant. The electric conductivity of the can water after the preset operation time is measured, and the corrected blow rate is calculated from the measured electric conductivity. Here, the concentration of canned water is the amount of solute (total evaporation residue) in the solvent (water), but the following relationship is established between the total evaporation residue in water and electrical conductivity. . Total evaporation residue [mg / l] = 0.7 × electrical conductivity [μs
/ Cm] Therefore, the concentration of the can water can be calculated by the electric conductivity instead of the total evaporation residue. For example, the electric conductivity of can water is E [μs / cm], the burning time is T [h], the actual evaporation amount is G [kg / h], the amount of retained water is L [l], and the electric conductivity of feed water is E _0. [Μs / cm], concentrated blow amount is B
[Kg / h], and the concentration blow rate is α, the following equation holds. E = {E ₀ × L + E ₀ × (G + B) × T−E × B × T}
/ L E × {1+ (B × T) / L} = E ₀ × {1+ (G + B)
/ L × T} Since the enrichment factor is E / E ₀ , E / E ₀ = {1+ (G + B) / L × T)} / {1+ (B
× T) / L} because α = B / (G + B) E / E ₀ = {1+ (B × T) / (α × L)} / {1+
(B × T) / L} When T increases, E = E ₀ / α ...

The electric conductivity measuring sensor 6 constantly detects the electric conductivity of the can water in operation, and calculates the electric conductivity E ₂ of the can water after the elapse of a predetermined operation time and a predetermined predetermined can water. Compare with the electric conductivity E _1, and if they are different,
The electric conductivity E ₃ of the feed water is calculated by substituting the electric conductivity E ₂ of the detected can water and the preset concentration blow rate α ₁ in the above equation in the calculation unit of the controller 11 (E ₃ = E ₂ ×
α ₁ ), and then the electric conductivity E ₃ of this feed water and the electric conductivity E ₁ of the predetermined canned water are substituted into the above formula to calculate an appropriate concentration blow rate α ₂ (α ₂ = E ₃ / E ₁ = E ₂ /
E ₁ × α ₁ ), and the concentration blow rate is corrected to this value to automatically control the concentration of the can water. Therefore, it is possible to automatically respond to changes in the electrical conductivity of the feed water and always control the boiler water concentration at an appropriate concentration blow rate.

Next, a second embodiment of the present invention will be described with reference to the drawings. The same members as those in the embodiment of claim 1 are designated by the same reference numerals, and the duplicated description will be omitted. Figure 2
In the embodiment shown in, a sensor 17 for measuring the electrical conductivity of water to be supplied is inserted in the water supply pipe 2 of the boiler 1, and the sensor 17 is connected to the controller 11 via a communication line 18. is there. In this embodiment, the sensor for measuring the electric conductivity of the can water is unnecessary. Sensor 17 detects the electrical conductivity of the water to the water supply at all times, compared with the water supply of the electrical conductivity E ₅ in which predetermined detected water supply of electric conductivity E ₄ set in advance, if it is different In the calculation unit of the controller 11, the detected electrical conductivity E ₅ of the feed water and the preset electrical conductivity E ₁ of the can water are substituted into the equation to obtain an appropriate concentration blow rate α ₂ . And calculate (α ₂ = E ₅ / E
₁ ) Correct the concentration blow rate to this value to automatically control the concentration of can water. Therefore, it is possible to automatically respond to changes in the electrical conductivity of the feed water and always control the boiler water concentration at an appropriate concentration blow rate.

[0016]

As described above, according to the present invention, in a system for automatically controlling the concentration of canned water based on a preset concentration blow rate, the electric conductivity of a predetermined canned water and a predetermined operating time have elapsed. If the electric conductivity of the detected canned water is different, or if the electric conductivity of the predetermined feed water that is set in advance is different from the electric conductivity of the detected feed water, calculate the relevant numerical value with the controller and make it appropriate. Since the effective concentration blow rate is calculated and automatically controlled, the appropriate concentration blow rate can be corrected by correcting the concentration blow rate in response to the change in the electric conductivity of the water to be supplied.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an arrangement of respective devices of a multi-tube type once-through boiler that implements the method for controlling concentration blow according to claim 1 of the present invention.

FIG. 2 is an explanatory diagram showing an arrangement of respective devices of a multi-tube type once-through boiler that implements the concentration blow control method according to claim 2 of the present invention.

[Explanation of symbols]

 1 Boiler 7 Concentration blow valve

Claims (2)

[Claims] 1. Based on a preset concentration blow rate,
In the boiler 1 in which the concentration blow valve 7 is opened and closed to automatically control the concentration of the canned water, the operating time until the electric conductivity of the canned water becomes almost constant is preset, and the canned water after the operating time elapses. If the electric conductivity of the boiler is different from the electric conductivity of the predetermined canned water, the appropriate concentration blow rate is calculated using the following formula, and the concentration blow rate is corrected to that value. Blow control method. E: electric conductivity of canned water E = E ₀ / α ... E ₀ : electric conductivity of feed water α: blow ratio 2. Based on a preset concentration blow rate,
In the boiler 1 in which the concentration blow valve 7 is opened and closed to automatically control the concentration of canned water, the electrical conductivity of the water to be supplied to the boiler 1 is measured, and the measured electrical conductivity of the supplied water and the electricity of the predetermined supply water are measured. When the conductivity is different, an appropriate concentration blow rate is calculated by using the following formula, and the concentration blow rate is corrected to the value, a boiler concentration blow control method. E: electric conductivity of canned water E = E ₀ / α ... E ₀ : electric conductivity of feed water α: blow ratio