CN113108271A - Dry combustion determination method and dry combustion prevention control method for steam generator - Google Patents

Abstract

The invention relates to a dry combustion determination method and a dry combustion prevention control method for a steam generator, S1, starting the steam generator to work; s2, collecting the working temperature T (n) of the steam generator; s3, storing T (n) in an array; s4, carrying out difference processing on the working temperature to obtain dTc (n); s5, comparing dTc (n) with Y and updating Z; s6, if Z is X, using the current operating temperature t (n) as the boiling temperature value of the steam generator; if Z is less than X, updating Win of the currently acquired working temperature; s7, executing S4-S6 again; s8, if T (n) is more than or equal to Tmax + M and dTc (n) is more than or equal to dTcg, judging that the steam generator is dry-burning; if not, go to S7. And supplying water to the steam generator when dry burning is judged, and judging whether the steam generator is out of dry burning. According to the invention, the stable boiling temperature value of the steam generator is determined, so that the accuracy of dry burning judgment is improved.

Description

Dry combustion determination method and dry combustion prevention control method for steam generator

Technical Field

The invention relates to a dry burning prevention determination method, in particular to a dry burning prevention determination method and a dry burning prevention control method for a steam generator.

Background

The steam ager all needs steam generator to produce steam, under the assistance that does not have other level sensor, need judge that steam generator need make up water when and just need to judge that steam generator takes place dry combustion method when, but current common judgement steam generator dry combustion method all sets up a fixed dry combustion method temperature, steam generator judges promptly when reaching this temperature and burns for dry combustion method, but different steam generator all can lead to dry combustion method temperature different under the environment of difference (like different incrustation scale degree, NTC position slightly different), set up too high dry combustion method temperature again and influence the life-span of steam generator and temperature controller.

For example, chinese patent application No. CN109990260B (application No. 201711491749.0) discloses a method for detecting dry combustion of a steam generator, wherein the disclosed method performs differential processing on a sequence of collected temperature values, and the obtained temperature difference is an amount that is not related to the change of the operating temperature of the steam generator caused by the ambient temperature, the temperature deviation of accessories, and water scale, so as to isolate the dc component in the collected temperature and filter the ac temperature component (temperature fluctuation) caused by the intermittent heating operating cycle of the steam generator. However, in the above method, the stable temperature value used when judging whether the steam generator enters the stable working state is the preset value, and the subsequent dry-heating detection process is only performed when the steam generator reaches the stable working state.

Disclosure of Invention

The first technical problem to be solved by the present invention is to provide a method for determining dry-heating of a steam generator, which can determine a stable boiling temperature value of the steam generator according to an actual temperature change of the steam generator, so as to improve an accuracy rate of determining dry-heating of the steam generator.

The second technical problem to be solved by the present invention is to provide a dry-heating prevention control method for a steam generator, which prevents the situation of excessive water addition in the steam generator by timely exiting from a dry-heating state.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a dry combustion determination method for a steam generator is characterized by comprising the following steps: the method comprises the following steps:

s1, starting a steam generator to work;

s2, according to the sampling time t₀Collecting the working temperature T (n) of the steam generator, wherein T (n) is a temperature value sequence, and n is a positive integer;

s3, setting an empty array Win, and sequentially storing the working temperature T (n) collected in the working period Tp of the steam generator in the empty array Win to obtain Win [ [ T (1), T (2) …, T (m)]；m＝Tp/t₀；

S4, performing difference processing on the currently acquired working temperature t (n) to obtain a temperature difference dtc (n); wherein n mod m represents a remainder obtained by dividing n by m, and the initial value of n is m + 1;

s5, setting a variable Z, wherein the initial value of the variable Z is 0; comparing the temperature difference value dTc (n) with a preset temperature difference threshold value Y; if dTc (n) > Y, clearing the current Z and transferring to S6; if dtc (n) ═ Y, then subtract i from the current Z as the updated Z, and proceed to S6; if dTc (n) < Y, adding j to the current Z to be the updated Z, and going to S6; i and j are positive integers;

s6, comparing the current Z with the preset total number X; if Z is equal to X, the currently collected working temperature T (n) is used as a boiling temperature value Tmax of the steam generator, and the process goes to S8; if Z < X, updating Win [ n mod m ] of the currently acquired working temperature T (n), and going to S7;

s7, adding 1 to the value of n, and executing S4-S6 again;

s8, comparing the currently collected working temperature T (n) with a boiling temperature value Tmax and the current temperature difference value dTc (n) with a preset upper temperature difference value dTcg respectively; if T (n) is more than or equal to Tmax + M and dTc (n) is more than or equal to dTcg, the steam generator is judged to be dry-burned, and a corresponding signal is output; if T (n) < Tmax + M or dTc (n) < dTcg, then go to S7; wherein M is greater than 0.

According to the output corresponding signal, the second technical problem of the present invention can be solved by cutting off the power supply of the steam generator or limiting the current to the electric heating unit, and the like, but a better technical solution may be that when the steam generator is determined to be dry-burning by the above determining method, the corresponding signal is output to the water supply control unit of the steam generator, and further comprising the following steps:

s9, supplying water to the steam generator;

s10, adding 1 to the value of n and then executing S4 again;

s11, comparing the currently collected working temperature T (n) with a boiling temperature value Tmax and the current temperature difference value dTc (n) with a preset lower temperature difference value dTcd respectively;

if any one of the following conditions is satisfied, the steam generator exits from the dry burning, the water supply to the steam generator is stopped, and the operation returns to S7; if any one of the following conditions is not satisfied, execution proceeds to S9;

the judgment conditions are as follows: (1) Tmax-N is less than or equal to T (N); (2) t (n) is less than or equal to Tmax and dTc (n) is less than dTcd;

wherein N is greater than 0.

Compared with the prior art, the invention has the advantages that: according to the dry combustion determining method of the steam generator, the stable boiling temperature value of the steam generator is determined according to the temperature difference condition of the steam generator, and then the dry combustion state of the steam generator is determined according to the stable boiling temperature value of the steam generator. The stable boiling temperature value is obtained by comparing the temperature difference values of the plurality of time sequences with the preset temperature difference threshold value, so that the calculated stable boiling temperature value of the steam generator is slightly influenced by the environment according to the comparison of the actual temperature difference values, the judgment accuracy of dry heating of the steam generator is ensured, the corresponding dry heating prevention water supply is more accurate and timely, and the service life of a product can be effectively prolonged.

Drawings

Fig. 1 is a flowchart of a dry-fire determination method for a steam generator according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in fig. 1, a method for determining dry-heating of a steam generator includes the following steps:

s1, starting a steam generator to work;

s2, according to the sampling time t₀Collecting the working temperature T (n) of the steam generator, wherein T (n) is a temperature value sequence, and n is a positive integer; the bottom of the steam generator is provided with a temperature sensor for collecting temperature, and in the embodiment, the sampling time t₀Is 1 s;

s3, setting an empty array Win, and sequentially storing the working temperature T (n) collected in the working period Tp of the steam generator in the empty array Win to obtain Win [ [ T (1), T (2) …, T (m)]；m＝Tp/t₀M is a positive integer; in the embodiment, the working period Tp of the steam generator is 60s, that is, m is 60;

s4, performing difference processing on the currently acquired working temperature t (n) to obtain a temperature difference dtc (n); wherein n mod m represents a remainder obtained by dividing n by m, and Win [ n mod m ] corresponds to the n mod m number in the array Win; the initial value of n is m + 1;

s5, setting a variable Z, wherein the initial value of the variable Z is 0; comparing the temperature difference value dTc (n) with a preset temperature difference threshold value Y; if dTc (n) > Y, clearing the current Z and transferring to S6; if dtc (n) ═ Y, then subtract i from the current Z as the updated Z, and proceed to S6; if dTc (n) < Y, adding j to the current Z to be the updated Z, and going to S6; i and j are positive integers; i and j may be the same or different, and in this embodiment, i ═ j ═ 1;

s6, comparing the current Z with the preset total number X; if Z is equal to X, the currently collected working temperature T (n) is used as a boiling temperature value Tmax of the steam generator, and the process goes to S8; if Z < X, updating Win [ n mod m ] of the currently acquired working temperature T (n), and going to S7; in the present embodiment, X is 70;

calculating the updated Z values of a plurality of sampling sequences by the method in S5, wherein in S5, Z can be gradually increased to be close to X only when the temperature difference value of the sampling sequences is smaller than Y, Z is decreased when the temperature difference value of the sampling sequences is equal to Y, and when the temperature difference value of a certain sampling sequence is larger than Y, namely the temperature value of the current sampling sequence is abnormal at the moment, the Z value is cleared and recalculated, so that the stable boiling temperature value of the steam generator can be determined by the updating method of the Z value;

s7, adding 1 to the value of n, and executing S4-S6 again;

s8, comparing the currently collected working temperature T (n) with a boiling temperature value Tmax and the current temperature difference value dTc (n) with a preset upper temperature difference value dTcg respectively; if T (n) is more than or equal to Tmax + M and dTc (n) is more than or equal to dTcg, the steam generator is judged to be dry-burned, and a corresponding signal is output; if T (n) < Tmax + M or dTc (n) < dTcg, then go to S7; wherein M is greater than 0; in this example, M is 5, Tmax +5 ℃ is set to a dry-firing temperature, and dTcg is also 5 ℃.

A dry-burning prevention control method of a steam generator, which judges whether the steam generator is dry-burning or not and outputs a corresponding signal to a water supply control unit of the steam generator when judging that the steam generator is dry-burning, and further comprises the following steps:

s9, supplying water to the steam generator;

s10, adding 1 to the value of n and then executing S4 again;

s11, comparing the currently collected working temperature T (n) with a boiling temperature value Tmax and the current temperature difference value dTc (n) with a preset lower temperature difference value dTcd respectively;

if any one of the following conditions is satisfied, the steam generator exits from the dry burning, the water supply to the steam generator is stopped, and the operation returns to S7; if any one of the following conditions is not satisfied, execution proceeds to S9;

the judgment conditions are as follows: (1) Tmax-N is less than or equal to T (N); (2) t (n) is less than or equal to Tmax and dTc (n) is less than dTcd;

wherein N is greater than 0.

In the embodiment, N is 2, and Tmax-2 ℃ is set as the temperature for exiting dry burning; dTcd-2 deg.C

In the present embodiment, each preset parameter in the above steps is determined according to the actual steam generator characteristics, and if the steam generator is of other shape or power, or the position of the temperature sensor is different, these values may be different, and each preset parameter needs to be determined according to the actual situation.

Although the method of the present invention is limited to the dry burning determination of the steam generator, the method may be applied to the dry burning determination of other devices having similar operation to the steam generator, and the detailed description thereof is omitted.

According to the dry combustion determining method of the steam generator, the stable boiling temperature value of the steam generator is determined according to the temperature difference condition of the steam generator, and then the dry combustion state of the steam generator is determined according to the stable boiling temperature value of the steam generator. In the dry combustion prevention control method of the steam generator, the difference value between the temperature value of each time sequence and the temperature value of the corresponding sequence of the previous working period is used as the temperature difference value, so that the influence of the environment and the external condition can be effectively avoided, in addition, the variable Z is updated by calculating the comparison between the temperature difference values of a plurality of time sequences and the preset temperature difference threshold value, so that the stable boiling temperature value can be obtained when the Z is equal to the preset total number X, therefore, the calculated stable boiling temperature value of the steam generator is slightly influenced by the environment according to the comparison of the temperature difference values in the actual working process of the steam generator, the judgment accuracy of the steam generator is ensured, correspondingly, in the dry combustion prevention control method, when the dry combustion of the steam generator is judged by the method, the dry combustion of the steam generator is prevented by supplying water to the steam generator, so that the service life of the product, in addition, whether the current temperature meets the condition of exiting dry combustion or not is judged in real time in the water supply process, so that the condition that excessive water is added into the steam generator is avoided while the steam generator is controlled to exit the dry combustion in time.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (2)

1. A dry combustion determination method for a steam generator is characterized by comprising the following steps: the method comprises the following steps:

s1, starting a steam generator to work;

s2, according to the sampling time t₀Collecting the working temperature T (n) of the steam generator, wherein T (n) is a temperature value sequence, and n is a positive integer;

s3, setting an empty array Win, and sequentially storing the working temperature T (n) collected in the working period Tp of the steam generator in the empty array Win to obtain Win [ [ T (1), T (2) …, T (m)](ii) a m is a positive integer; m is Tp/t₀；

S4, performing difference processing on the currently acquired working temperature t (n) to obtain a temperature difference dtc (n); wherein n mod m represents a remainder obtained by dividing n by m, and the initial value of n is m + 1;

s5, setting a variable Z, wherein the initial value of the variable Z is 0; comparing the temperature difference value dTc (n) with a preset temperature difference threshold value Y; if dTc (n) > Y, clearing the current Z and transferring to S6; if dtc (n) ═ Y, then subtract i from the current Z as the updated Z, and proceed to S6; if dTc (n) < Y, adding j to the current Z to be the updated Z, and going to S6; i and j are positive integers;

s6, comparing the current Z with the preset total number X; if Z is equal to X, the currently collected working temperature T (n) is used as a boiling temperature value Tmax of the steam generator, and the process goes to S8; if Z < X, updating Win [ n mod m ] of the currently acquired working temperature T (n), and going to S7;

s7, adding 1 to the value of n, and executing S4-S6 again;

s8, comparing the currently collected working temperature T (n) with a boiling temperature value Tmax and the current temperature difference value dTc (n) with a preset upper temperature difference value dTcg respectively; if T (n) is more than or equal to Tmax + M and dTc (n) is more than or equal to dTcg, the steam generator is judged to be dry-burned, and a corresponding signal is output; if T (n) < Tmax + M or dTc (n) < dTcg, then go to S7; wherein M is greater than 0.

2. A dry-burning prevention control method for a steam generator is characterized by comprising the following steps: the dry-fire determination of the steam generator is performed by the method as set forth in claim 1, and when it is determined that the steam generator is dry-fired, a corresponding signal is outputted to a water supply control unit of the steam generator, and further comprising the steps of:

s9, supplying water to the steam generator;

s10, adding 1 to the value of n and then executing S4 again;

s11, comparing the currently collected working temperature T (n) with a boiling temperature value Tmax and the current temperature difference value dTc (n) with a preset lower temperature difference value dTcd respectively;

if any one of the following conditions is satisfied, the steam generator exits from the dry burning, the water supply to the steam generator is stopped, and the operation returns to S7; if any one of the following conditions is not satisfied, execution proceeds to S9;

the judgment conditions are as follows: (1) Tmax-N is less than or equal to T (N); (2) t (n) is less than or equal to Tmax and dTc (n) is less than dTcd;

wherein N is greater than 0.

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