JPH0244119A - Optimum combustion control method for boiler - Google Patents

Abstract

PURPOSE:To perform total optimum combustion control of a power plant while taking the environmental condition into consideration and taking good care of the boiler installation concerned by a method wherein at the time of integrated evaluation of the combustion state of a boiler, based on indexes obtained by an environmental factor, a safety factor, and an efficiency factor, a determined integrated index is compared with an ideal value to control the combustion of a boiler. CONSTITUTION:In consideration of a weight between an integrated index T of combustion, an index Tu obtained from an environmental factor, an index Ts obtained from a safety factor, and an index Tw obtained from an efficiency factor and the tolerance grade of each measurement, a value of T=Tu+Ts+Tw is determined, through the comparison of the value with 100 being the ideal value of a combustion state integrated index T, operation of a boiler is effected in a state in which the value of the integrated value is increased to a maximum. In which case, Tu, Ts, and Tw are determined by formulas I-III, and betau+betas+betaw is equal to 100, wherein betau, betas, and betaw are weighted factors of an environment, a safety, and an efficient element, alphaun, alphasn, and alphawn are measurements of the (n) of environment, safetly, and efficiency factors, and [alphaui] is a constant value obtained by providing measurements of alphaui, alphasi, and alphawi factor according to tolerance grades of 1, 2, 3...m.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optimal combustion control method for a boiler used in thermal power generation.

(Prior Art) Until now, there has been no method for comprehensively evaluating the environment, safety, and efficiency factors of boiler combustion and performing optimal boiler combustion control.

(Problem to be solved by the invention) When burning a boiler for power generation, the combustion state must be comprehensively monitored, evaluated and diagnosed, and even abnormal Measures, instructions and predictions of operating conditions are required. However, conventionally,
These monitoring, evaluation, diagnosis, and action functions often relied on the skills of experienced operators. Furthermore, automatic control of combustion conditions is limited to fuel and air control commensurate with load commands, etc., and adjustments in the event of an abnormality rely on manual operations by an operator.

Furthermore, conventionally, there has been no clear method for comprehensively evaluating boiler equipment for thermal power generation systems, such as the degree of deterioration of the boiler equipment, its efficiency loss and safety due to overuse, or the environmental conditions around the thermal power plant.

Therefore, in the present invention, in order to solve such problems, the combustion evaluation of power generation boilers is performed by comprehensively grasping and diagnosing the three elements of environment, safety, and efficiency, and paying attention to the surrounding environment. It also aims to provide an overall optimal combustion control method for a power generation plant that operates while taking care of the boiler equipment.

By the way, the main mission of boiler equipment in a thermal power generation system is to convert the energy of fuel into steam energy through combustion. Compared to conversion to energy, the phenomenon is more complex and there are many engineering problems. Particularly, there are many failures in combustion-related parts of boiler equipment, and boiler equipment is individually designed to meet various regulations for operational characteristics, starting from the type of fuel. Furthermore, in actual operation, each boiler often exhibits unique characteristics. These different characteristics are basically caused by combustion, so evaluation of the combustion state is extremely important for proper operation of boiler equipment. In particular, since this combustion state greatly affects the operation of boiler equipment from the aspects of environment, safety, and efficiency, it is important to analyze these three elements and comprehensively evaluate their interrelationships in terms of the operation of this type of equipment. , essential.

Here, the environmental factors include SOX%NOx- in boiler exhaust gas, which is currently subject to regulations under pollution control agreements established by local governments in addition to government regulations.

There are soot and dust, and even exhaust gas temperature. In addition, safety elements include safety elements during operation and equipment maintenance elements while stopped; the former includes ensuring continuous operation, safe combustion, prevention of explosions and puffs, prevention of local heating, and prevention of boiler tube damage. However, the latter also includes reducing equipment deterioration, equipment diagnosis and preventive maintenance, streamlining repair work, and implementing improvement work. Furthermore, efficiency factors include reduction of heat loss due to condenser loss on the turbine side and exhaust gas loss on the boiler side, reduction of 0□%, and monitoring of the internal power of the boiler equipment.

(Means for Solving the Problems) As shown in FIG. 1, the combustion state control system used in the boiler optimum combustion control method of the present invention includes a boiler 1, a combustion state monitoring section that constitutes a combustion state monitoring/diagnosis section. 2. It consists of a combustion state diagnosis section 3, a combustion state optimum adjustment planning section 4, and a combustion state adjustment section 5.

To explain its function, first, changes occur in the boiler in a steady state due to external factors such as power supply commands and issuance of photochemical tong alarms.The function is to measure changes in the boiler operating state at this time. This is the combustion state monitoring section 2.
It is. This allows us to comprehensively understand not only the state variables that represent the optimization of combustion conditions such as flame temperature and exhaust gas properties, but also the operating conditions of the boiler, such as changes in tube wall temperature and heat absorption caused by these variables. Ru. Furthermore, the combustion state diagnosis section 3 expresses the combustion state using an index that takes into account various limiting conditions (1-), takes into account the weight of boiler characteristic H (7), +7, and determines whether the current operating state is appropriate. . If it is determined that the operating condition is not appropriate, that information is sent to the optimum combustion condition adjustment planning section 4.
Passed on to. Here, two machines #M are operated 60 based on the information from the diagnostic section 3 and the monitoring section 2, that is, one is
This is an optimal adjustment function, which instructs the combustion conditions to be adjusted, the amount of adjustment, and the 1-b method. j-ta, other functions are,
This is an optimal 51-screen function that sets the optimal time schedule for the combustion conditions to be adjusted. The combustion adjustment unit 5 performs combustion bar adjustment based on the command from the optimum adjustment unit 4. If there is no command, constant value feedback control is performed and automatic optimal combustion control becomes possible.

In order to comprehensively evaluate boiler combustion using the boiler combustion state control system configured as described above, the present invention
A total of 1 boiler measurement items from the three perspectives of safety and efficiency.
'lP] 1-ru. Instead of using the measured value as it is for comprehensive evaluation, we have introduced a tolerance class that judges the quality of the #J constant value from various conditions and ranks it (2).
Convert those measured values into constant values, and further calculate the above three viewpoints I.
XI l:: The distance f between phases lJ' is quantified by fI and T: weighting coefficient and 12, which is ().

That is, the present invention provides a comprehensive evaluation of the combustion state of the boiler, and a comprehensive combustion index obtained from the T1 environmental factor.
TTsI index obtained from safety factors
The index obtained from the S efficiency factor is T and 1. The weight between each index and the tolerance of each measurement value 1
Considering the class I2, find the value of 1, '1--r+T+T IJ S ν5, and use this value as the ideal value of the combustion state comprehensive index T]-CI+) and the overall tF target' The boiler is operated with the summer value M as high as possible.

Here, Tu, Ts Oko, bi'r hazorezere+
1 S ν (here,
β:f! Weight coefficient of three boundary elements, 1” α0. ■, αlJ2'``'αlJn'' environmental prisoners]
-dll [constant value, [α]; α, the measured value of the factor is 1:2Ts1
1J 1 3...n] Classification 12. , depending on the class'r-1j gill 4-16 constant Ts1 (here, β;
Weighting factor of safety element, σsl'"S2'""SI
The measured value of I'' safety factors, [α, iJ; α, the measured value of 1 factor is 1.23...
Divided into m wealth classes 7, and according to the class (2 I - > obtained 6 constant value) (where, β ; weight coefficient of efficiency element,
ν σ5. ■, α, 2. ... αWn; Measured value of n efficiency factors, 1', a, t ] ; Measured value of αvi factor is 1
．． 23... divided into m tolerance classes, 7, +4 according to the m class] -), filtration constant value) β → -β, 2@-
β = 1. OO and Hi3゜1"+1 υ, and ka・"), (Function) First, according to the present invention, the overall evaluation of the combustion state of the boiler is j-
7, the first step is 1-, -<7, and the selection of boiler total It items. In general, measurement items related to boiler equipment [1 is per boiler], OoO-・3
There are approximately 000, but if you select the term ``1'' related to the combustion evaluation index, the result will be as shown in Table 1.

Next, as a second step, basic formulas related to the environment, safety, and efficiency will be introduced in order to index comprehensive evaluation.

The reason for this is that the quality of combustion during operation of the power generation boiler is determined by quantifying these three elements.

Here, the indicators of these three elements are T (environmental prisoner), T
(safety factor), T (efficiency factor), and S
Let T be the comprehensive evaluation index of ν combustion (100 in an ideal state). By the way, T, T
, T are indicators that should be evaluated independently of each other u S ν , so there is a method of broadly classifying them and considering their sum or product as a comprehensive indicator.

In other words, for their sum, T-T+T+T ・・・・・・・・・(1
) u S v Also, for their product, T-T XT XT −・−−−−−
・−(2) υ S v .

Taking the logarithm of both sides of the above equation (2), we get ! og T-1og T +Iog T +log
S, and looking at equation (3) with a logarithmic index, T...(3
) 1-1+1+1 ・・・・・・・・・
(4) υ S w .

That is, it can be seen that equation (2) may be replaced by equation (4) expressed using a logarithmic index. Furthermore, when comparing Equation (1) and Equation (4), Equation (1) has good accuracy for a high level of evaluation (rating point) of the entire system, whereas Equation (
It can be seen that 4) has higher accuracy for low evaluation levels (so-called abnormal times).

In fact, when operating a boiler, an alarm system is activated in case of deterioration of environmental values, and for safety, in addition to this alarm system, an automatic emergency stop system is installed. However, warning systems for boiler efficiency deterioration are usually not provided.

This means that the comprehensive combustion evaluation of the boiler only needs to be performed during normal operation, and when an abnormality occurs, it is necessary to rely on another system that is quick. Therefore, here, it is sufficient to consider the sum of the above equation (1).

Therefore, based on this idea, the contents of equation (1) are defined below.

Zunawaji, from formula (1), The index 'r obtained from environmental factors is turtle" becomes.

Here, β: Weight coefficient of environmental element, 1" α1. ■, α1, 2. ...α3. . : Measured values of n environmental factors, [α,]: αLJI factor constant values are divided into 1.2°J1 3...nl tolerance classes, and the constant value l given according to the class is be.

Similarly, in 17, the index T obtained from the safety factor is good.

Here, β ・Weighting coefficient of safety prize, αsl'αs2' ...αsn Measured value of 20 safety factors, [α, 1]: α, i factor measurement (16 to 1°2° 3...
- Class 174 is given to m's wealth class, and it is a constant value given according to that class.

Furthermore, in the same manner as 17, the index Tν from the efficiency factor becomes.

12, β: weighting coefficient of efficiency element, α, α, 2. ... αwn'' efficiency factor measurements, [αvl): α, intrinsic factor measurements as 1, 2.3... [n
It is a constant value given to the wealth class of 17 and given according to that class.

Here, β 10 β + β −100 (8) u
S v Therefore, in the present invention, from equations (5), (if) and (7), the weighting coefficient of each factor and the tolerance of each factor 1 class (
'rul'lJ2'''um'asl'
"s2'""sn'αwl'αv2'
..., αi, 1) (, °B, environmental prisoner (T)
), safety factor (T) and efficiency factor U
S('r) is calculated, the three-factor index 1st shift fit(T'') is taken, and compared with the ideal value (100 points), a comprehensive combustion evaluation of the boiler in a specific combustion state is performed.

The comprehensive combustion evaluation according to this study is shown in Table 1 (32 Aroyo 1
;・Select the price term [1 appropriately, /P, and set the wealth class to realistic 1 for each price term [I]. Deprivation/t'
<; By 1, it is possible to create an evaluation system with high reliability and clarity.Roughly, new evaluation items can be set by adding the total Al+ value and composing multiple measured values. That's the b-th iE.

Then, 1. Comprehensive combustion 19 of the obtained boiler ('value 1
．． Combustion status of the incineration state control system limited to v; 75
Move the JJ adjustment section 1'l to perform combustion operation of the boiler.

(Example) Comprehensive combustion evaluation of boiler based on the example of Akira Akira, Pete
Please explain about the whelk.

First of all,) 3S Anji'i! ,, - Ripenkazu Taitaka's [Teniro 1 series;
30,β-・IIS
W2C.

According to the environmental factors Table 1, the total number of environmental factors is 5 (n"5), but the SOx concentration is determined from the 8 minutes in the fuel, and the overcity and C are sufficient. Since there is no data accumulation, AL, here, the concentrations of NOx, CO, and soot are targeted (Zunawaji, n.-3).

The NOx concentration is 5, and depending on the difference (ΔN) from the pollution prevention agreement value with local governments, etc., the tolerance class is 1-1 as shown in Table 2.
Set V(m-5).

Table 2 shows the unit of scale: ppm) Regarding the CO concentration (C), there are currently no agreed or regulated values for this concentration. However, tolerance classes 1 to 2 (m-4) are set as shown in Table 3 based on past driving results.

Table 3 Table (concentration unit: ppm) Furthermore, regarding soot and dust degree (D), this concentration is determined at the dust collector inlet (economy unit outlet) as shown in Table 4, tolerance class 1-V ( m-5) (concentration unit; mg
/N end) Therefore, regarding the operating conditions related to environmental factors, the measurement results show that the NOx concentration (ΔN) is 15 ppm below the agreed value, the CO concentration is 80 ppm, and the soot and dust concentration is 1 at the ECO exit.
When it is 30 mg/NTrl, from the above formula (5), it becomes as follows.

Safety factors Next, regarding safety factors, according to Table 1, the total number is 8.
(n-8). However, here we will focus on SH and RH metal temperatures and furnace draft, for which there is sufficient data and is easy to analyze. First, SH, RH
Regarding metal temperature tolerance (Δt), tolerance classes I to V (m-5) can be set as shown in Table 5.

Table 5 Table 6 (Tolerance unit: Temperature difference from design value °C) Furthermore, regarding furnace pressure fluctuation (ΔP), tolerance class 1-V (m-5) is set as shown in Table 6.

(Unit: mmAq) Therefore, regarding the operating conditions related to safety factors, if the SH and RH metal temperature margin (margin from the design value) is 7°C from the measured value and the furnace pressure fluctuation is 12mmAq, then Become.

Efficiency Factors Regarding efficiency factors, according to Table 1, the total number is 6 (
n-6). Here, we will focus on plant efficiency, boiler efficiency, and 02 concentration, for which sufficient data is currently available.

First, regarding plant efficiency, tolerance class 1=IV(m-4) is set as shown in Table 7.

Table 7 Furthermore, one is placed at the boiler Eeo outlet 02a, and its tolerance class 1 to rV (rrn = 4) is similarly set as shown in Table 9.

Table 9 (Unit of plant efficiency change (Δ): % difference from design value in absolute value ηp) Also, regarding boiler efficiency, the tolerance classes I to IV (m = 4) are set as shown in Table 8. do.

Table 8 (Jν position of 02a degree change (Δξ); % difference from design value in absolute value) Therefore, from the measurement results, the operating conditions related to efficiency factors are
Assuming that the plant efficiency is 0.15% better than the set value, the boiler efficiency is 0.3% better than the old value, and the 02 concentration is 0.15% lower than the design value, from the above equation (7), (% difference in boiler efficiency change from design value) (Δ7, )) unit: Absolute value.

Comprehensive evaluation (-), 3IJ of environment (T), safety (T), and efficiency (T) factors in the above-mentioned operating conditions
When making a comprehensive evaluation of the S ν element, from equation (1), the comprehensive evaluation T is: T-=-T +T value IC
] 69 points per 0 points.

Then, based on this comprehensive evaluation, the combustion state of the boiler is controlled by the combustion state adjustment section, and the combustion operation of the boiler is performed one by one.

(Effects of the Invention) According to the present invention, the factors related to the environment/safety Q/efficiency of the boiler are measured at a predetermined location, and the tolerance class is calculated from the above calculation formula in consideration of the weighting coefficient. Finger IT from environmental factors
By calculating the index T from the safety factor and the index 1iT from the JS efficiency factor, and comparing the sum with the ideal ν value (100), it is possible to comprehensively evaluate the combustion state of the boiler, and also to maximize the comprehensive index T. It is possible to operate the boiler in a state where the I- is at the highest possible level. As a result, automatic control of combustion will become possible, and an overall operation support system for the power plant will be constructed that takes into consideration the environment around the thermal power plant, the age of the boiler equipment, etc.

[Brief explanation of the drawing]

FIG. 1 shows a conceptual diagram of a system for controlling the combustion state of a boiler used in the optimum combustion control method for a boiler according to the present invention. DESCRIPTION OF SYMBOLS 1... Boiler, 2... Combustion state monitoring part, 3... Combustion state diagnosis part, 4... Optimal adjustment planning part, 5... Combustion state 4 adjustment part.

Claims (1)

[Scope of Claims] A boiler, a combustion state monitoring/diagnosis section that monitors and diagnoses the combustion state of the boiler, and an optimal adjustment planning section that sets the optimum combustion state of the boiler based on the comprehensive evaluation of the combustion state monitoring/diagnosis section. In the optimum combustion control method for a boiler, which comprises a combustion state adjustment section that controls combustion of the boiler based on commands from the optimum adjustment planning section, when the combustion state monitoring/diagnosis section comprehensively evaluates the combustion state of the boiler, The comprehensive index is T, the index obtained from environmental factors is T_u, the index obtained from safety factors is T_s, the index obtained from efficiency factors is T
When _w, T_u, T_s and T_w are respectively T_u=β_u([[α_u_1]+[α_u_2]+
...[+α_u_n]]/n), (here, β_u; weighting coefficient of environmental factors, α_u_1, α_u_2, ... α_u_n; measured value of n environmental factors, [α_u_i]; measured value of α_u_i factor 1, 2, 3
...divided into m wealth classes and a constant value given according to the class) T_s = β_s ([[α_s_1] + [α_s_2] +
...+[α_s_n]]/n), (here, β_s;
Weight coefficients of safety factors, α_s_1, α_s_2, ... α_s_n; Measured values of n safety factors, [α_s_i]; Measured values of α_s_i factors are set to 1, 23.
... a constant value that is divided into m wealth classes and given according to the class) T_w = β_w ([[α_w_1] + [α_w_2] +
...+[α_w_n]]/n) (where, β_w; weighting coefficient of efficiency element, α_w_1, α_w_2, ...α_w_n; measured value of n efficiency factors, [α_w_i]; measured value of α_w_i factor 1, 23・
...m of wealth classes and a constant value given according to the class) And, assuming β_u + β_s + β_w = 100, T = T
_u+T_s+T_w is calculated, and the overall evaluation of the combustion state is set as the ideal value (index value; 100
) An optimal combustion control method for a boiler, characterized in that the boiler combustion is controlled in a state where the value of the comprehensive index T is maximized compared to the above.