CN107401923A - Kiln burning efficiency control method - Google Patents
Kiln burning efficiency control method Download PDFInfo
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- CN107401923A CN107401923A CN201610330310.9A CN201610330310A CN107401923A CN 107401923 A CN107401923 A CN 107401923A CN 201610330310 A CN201610330310 A CN 201610330310A CN 107401923 A CN107401923 A CN 107401923A
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Classifications
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- 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
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B14/20—Arrangement of controlling, monitoring, alarm or like 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
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Abstract
The present invention provides a kind of kiln burning efficiency control method, is related to the Combustion System such as industrial furnace and thermal boiler field, it is possible to increase fume afterheat utilization rate and fuel gas buring efficiency.This method includes：S1, preheat the waste heat of the combustion air of feeding stove in the flue gas discharged with gas proportioning and before mixing from the stove；S2, make to be burnt with the combustion gas in the feeding of the combustion air after the being preheated stove；S3, during burning and carrying out, according to the temperature of burner hearth in the stove, produce the temperature of medium or the pressure of steam, adjust the conveying capacity of the combustion gas；S4, during burning and carrying out, according to the oxygen content in the flue gas, dynamically adjust the flow of the combustion air.
Description
Technical field
The present invention relates to the Combustion System field of industrial furnace and thermal boiler etc., more specifically to one
Kind kiln burning efficiency control method.
Background technology
In current metallurgy and casting processing industry, natural gas smelting furnace (aluminum melting, copper, iron) is generally to build
And if the smelting equipment used, the kind equipment common problem are that natural gas energy consumption is higher and External Environment
It is big to discharge waste heat, exhaust gas volumn.Natural gas high energy consumption directly results in production cost increase so that enterprise lacks city
Field economic competitiveness.The kind equipment can cause the negative effect such as environmental pollution and hot cell effect, or even reduce production
Quality and production efficiency, obstacle is brought to enterprise and socio-economic development, how not only to have promoted economic development but also
Green generation is kept, is to promote the sector and the important topic of social development.In fact, high energy consumption smelting furnace
Or plan relies on the construction unit of the smelting furnace of production of energy, increasingly pay attention to selection energy-saving and high efficient rate in recent years
Smelting furnace.
Why there is above mentioned problem in existing smelting equipment, main reason is that efficiency of combustion control and waste heat
The link that production cycle utilizes is more weak.Specifically, in efficiency of combustion controlling unit, existing air-fuel ratio
Example valve adjusts air demand according to the press ratio of combustion air, however, due to the material being melted in burner hearth
Expect that in the oxygen amount that different classes need be uncertain, therefore, can not be obtained most preferably according to the air-fuel ratio of setting
Combustion efficiency.Also, conventional pressure formula (fixed) air-fuel ratio valve generally using least favorable oxygen content as
Proportion adjustment, therefore, in addition to least favorable state, necessarily occur excessive combustion air under other states, because
And excessive natural gas can be consumed.
Link is utilized in waste heat production cycle, now most of waste heat is used for production and living hot water, but for row
The high-grade waste heat that cigarette excess heat is big, temperature is high, it is directly used in production and living hot water and compares waste, if can be
This part high-grade waste heat is produced for melting in smelting equipment, is beneficial to reduce gas consumption,
With being more economical and environmentally friendly worth greatly.
As can be seen here, the smelting equipment with energy-saving and emission-reduction, green production and reduction production cost is that production is single
Position is built, the trend of restoration and reuse.
The content of the invention
The technical problem to be solved in the present invention is, for high energy consumption and burning in existing industrial furnace technology
The defects of efficiency is low, there is provided a kind of fume afterheat utilization rate, the kiln burning efficiency of fuel gas buring efficiency high
Control method.
The technical solution adopted for the present invention to solve the technical problems is：Construct a kind of kiln burning efficiency control
Method processed, comprises the following steps：
S1, make the combustion air of feeding smelting furnace with gas proportioning and before mixing by from the melting fire grate
Waste heat preheating in the flue gas gone out；
S2, make to be burnt with the combustion gas in the feeding of the combustion air after the being preheated smelting furnace；
S3, during burn and carry out, according to the temperature of burner hearth in the smelting furnace, production medium
The pressure of temperature or steam, adjust the conveying capacity of the combustion gas；
S4, during burning and carrying out, according to the oxygen content in the flue gas, dynamically described in regulation
The flow of combustion air.
Alternatively, the smelting furnace is provided with multiple for air mixture and the mixing burner of combustion air, described
Step S1 is specially：
Combustion air is alternately passed through each mixing burner and be sent into the smelting furnace, and make the melting
The flue gas that fire grate goes out corresponds to the combustion air, is alternately sent to each mixing burner to described combustion-supporting
Wind is discharged after being preheated,
After the step S1, methods described also includes：Make the combustion air and the combustion gas alternately
Mixed at each mixing burner.
Alternatively, the step S3 is specifically included：
S31, burn carry out during, in real time measure burner hearth temperature, produce medium temperature,
Or the pressure of steam, and using measurement result as process variables；
S32, temperature, the temperature of production medium or the pressure of steam according to manufacturing technique requirent to burner hearth
Power sets target pre-set parameter, according to the process variables, the target component setting value, profit
Combustion gas target conveying capacity is determined with pid control algorithm；
S33, regulating gas conveying capacity make it equal to the combustion gas target conveying capacity.
Alternatively, S31, burn carry out during, in real time measurement production medium temperature, and will
Measurement result is as process variables；
S32, the temperature sets target pre-set parameter according to manufacturing technique requirent to production medium, and
During burning is carried out stage by stage, judge whether process variables are higher than described in each stage respectively
The target component setting value, if so, then entering step S33Y, if it is not, then entering step S33N；
S33Y, judge that the process variables are rising or decline in former and later two stages, if
Decline, then maintain fuel gas transmission amount constant, if rising, then the fuel gas transmission amount is successively decreased default width
Degree；
S33N, judge that the process variables are rising or decline in former and later two stages, if
Rise, then maintain fuel gas transmission amount constant, if declining, then the fuel gas transmission amount is incrementally preset width
Degree.
Alternatively, the step S4 is specifically included：
S41, during burning and carrying out, measure the air pressure of the outer air of the smelting furnace, temperature and wet
Degree；
S42, according to the air pressure of air, temperature, humidity and the conveying of the combustion gas outside the smelting furnace
Amount, determines minimum combustion-supporting wind flow；
S43, the lower limit value according to the minimum combustion-supporting wind flow, adjusting the flow of the combustion air makes it
The minimum combustion-supporting wind flow is approached within a preset range；
S44, the oxygen content in the flue gas, the flow of the combustion air is further adjusted
To cause the oxygen content in the flue gas to tend to preset value.
Alternatively, the step S4 is specifically included：
In the burner hearth constant temperature stage, the conveying capacity of the combustion gas and the oxygen content in the flue gas are recorded in real time,
Determine corresponding oxygen content during the conveying capacity minimum of the combustion gas, it is corresponding during by the conveying capacity minimum should
Setting optimum value of the oxygen content as combustion-supporting wind flow in the constant temperature stage, adjusting the flow of the combustion air makes
It approaches the setting optimum value.
Alternatively, the step S4 is specifically included：
In the burner hearth temperature rise period, the flow of the combustion air is altered in steps, and records fire box temperature change
Oxygen content when speed takes maximum in corresponding flue gas；
The flow of the combustion air is adjusted so that the oxygen content in current flue gas tends to the speed of fire box temperature change
Corresponding oxygen content when rate takes maximum.
Implement the kiln efficiency of combustion control method of the present invention, have the advantages that：Due to combustion air
Waste heat in the flue gas discharged with gas proportioning and before mixing from furnace preheats, it is thus possible to improves cigarette
Gas utilization rate of waste heat, in addition, during progress of burning, it is situated between according to the temperature of burner hearth, production in stove
The temperature of matter or the pressure of steam, the conveying capacity of regulating gas, always according to the oxygen content in flue gas, dynamic
Ground adjusts the flow of combustion air, it is thus possible to improves the efficiency of combustion of combustion gas, reduces gas consumption.
Brief description of the drawings
Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing：
Fig. 1 is the flow chart of kiln burning efficiency control method provided in an embodiment of the present invention；
Fig. 2 is the structural representation that flue gas is preheated to combustion air in the embodiment of the present invention；
Fig. 3 is the structural representation of burner in the embodiment of the present invention；
Fig. 4 shows for the conveying capacity of the temperature adjustment combustion gas of the temperature according to burner hearth in stove or production medium
It is intended to；
Fig. 5 is the schematic diagram according to the conveying capacity of steam pressure regulating gas；
Fig. 6 dynamically adjusts the schematic diagram of the flow of combustion air for the oxygen content in flue gas.
Embodiment
In order to which technical characteristic, purpose and the effect of the present invention is more clearly understood, accompanying drawing is now compareed
Describe the embodiment of the present invention in detail.
The problem of combustion system efficiency of combustion is low, fume afterheat discharge is high, it is for industrial furnace or boiler
Reduction gas consumption, save production cost and reduce disposal of pollutants, kiln burning efficiency provided by the invention
Control method is mainly set about in terms of following three.First, make combustion air with being preheated before gas proportioning,
Be advantageous to combustion reaction heat；Second, according to regulating gas such as fire box temperature or the temperature/pressures for producing medium
Deng the conveying capacity of fuel；3rd, according to oxygen content in exhaust smoke dynamic regulation combustion air volume, realize with dynamic air-fuel
Burnt than control, avoid excessive or deficiency combustion air from causing gas consumption to increase, so as to improve efficiency of combustion,
Reduce heat loss and disposal of pollutants.
Fig. 1 is the flow chart of kiln burning efficiency control method provided in an embodiment of the present invention.As shown in figure 1,
Kiln burning efficiency control method specifically includes following steps.
S1, make the combustion air of feeding stove in the flue gas discharged with gas proportioning and before mixing from stove
In waste heat preheating.
The present embodiment can use exchange type and both preheating methods of commutation heat accumulating type.Wherein, commutate accumulation of heat
Formula applies to heat-storage type burner, and its principle is periodically to replace commutation accumulation of heat or handed over using heat-storing material heat
Change, combustion air is absorbed fume afterheat, combustion air is preheated to temperature of 120 DEG C or so less than fire box temperature
Degree, and exhaust gas temperature is reduced to less than 150 DEG C and is discharged into again in air.
Fig. 2 is the structural representation that flue gas is preheated to combustion air in the embodiment of the present invention.As shown in Fig. 2
In order to realize flue gas to combustion air preheat, can for mix and light mixing burner upstream side, side by side
The pipeline of be respectively used to circulate flue gas and the combustion air that circulates that set, and heat exchange is formed respectively in two pipelines
Portion, the good heat pipe of thermal conductivity are placed in heat exchange department across two pipelines.So, heat pipe can be by temperature
The heat transfer combustion air relatively low to temperature in the higher flue gas of degree, so as to realize flue gas to the pre- of combustion air
Heat.By preheating, burning fast reaction can be catalyzed and release heat.
In the present embodiment, by the way of alternately preheating, specifically, can be set in the burner hearth of face stove
There are multiple mixing burners, in combustion, combustion air is alternately passed through each mixing burner and be sent into stove,
And the flue gas from stove discharge is corresponded to combustion air, alternately it is sent to each mixing burner and combustion air is carried out
It is then exhausted from after preheating, i.e. being mixed at one at burner makes flue gas preheat combustion air, then, switching
Preheated to next mixing burner, and in the mixing burner, be so repeated.
In addition, on combustion air and the mixing and burning of combustion gas, in the past, most of heat storage type combustion it is combustion-supporting
Wind is periodicity accumulation of heat commutation, but combustion gas but not reversing combustion, that is to say, that combustion gas is sent directly into burner hearth
Afterwards again with the combustion air mixed combustion from different directions.Conventional this mixing and combustion system have ignored combustion
The process of efficiency and heat transfer is burnt, its efficiency of combustion is relatively low, and heat transfer effect is poor.Its efficiency of combustion is relatively low
Reason is, relative to combustion air, combustion gas enters burner hearth from other entrance (i.e. burner), expands in combustion gas
Before dissipating, its density is larger, and therefore, mixing with combustion air is simultaneously uneven, so, in order to the greatest extent may be used
Can completely burned, need to ensure that the oxygen amount in combustion air is far longer than reaction requirement amount, but excessive combustion air
Some gases and more reaction heat can be inevitably taken away, thus efficiency of combustion is relatively low.Heat transfer effect
The reason for poor, is, on the one hand, is limited by furnace cavity, combustion flame length is shorter；On the other hand, phase
For combustion air, combustion gas enters burner hearth from other burner, but because in the exit of burner, combustion gas is with helping
Combustion prevailing custom is unmixed or undercompounding, therefore combustion flame can not be formed in the exit of burner, the above two
The stroke that aspect result in flame (and its heat smoke) jointly is reduced, and also just reduces heat transfer (herein
Heat transfer refer to, heat transfer caused by burning to production medium or the hot water for producing steam) time,
Cause excess heat in flue gas larger.
For the problem, in the present embodiment, after step S1 is carried out, combustion air is set to replace with combustion gas
Ground mixes at each mixing burner, that is to say, that combustion air enters stove with combustion gas from the same burner that mixes
Thorax, while reversing combustion.A kind of structure of burner is as shown in figure 3, form a fuel gas hole and ring in burner
Six combustion air diffusing holes being wound on around the fuel gas hole.According to the structure, combustion gas mixed with combustion air compared with
To be abundant, and the root of flame directly can be formed in the exit of burner, both ensure that abundant burning, again
The stroke of flame and flue gas in burner hearth is elongated, therefore, it is possible to improve efficiency of combustion and heat transfer effect, is reduced
Waste heat discharges.
Because burning when combustion air volume it is more much bigger than combustion gas (combustion of natural gas air-fuel ratio be 10:1, gas-fired is empty
Combustion is than being 3.75:1), if combustion-supporting air temperature is relatively low before burning, there will be part burning liberated heat quilt
For heat fire air quantity, in this step, by being preheated to combustion air, by increasing capacitance it is possible to increase combustion air with
Enthalpy before combustion gas reaction, is advantageous to accelerated combustion physical-chemical reaction speed, reduces for heating combustion air
Combustion reaction heat so that combustion reaction heat be mainly used in lifted flue gas (flue gas is with the shape of different air current compositions
Formula with production medium carry out heat transfer) temperature, it is thus possible to improve combustion temperature in hearth quickly.
Although the preheating only to combustion air is illustrated in this step, however, can also be in this step simultaneously
Combustion gas is preheated, for example, it is contemplated that the burning-point to natural gas is 540 DEG C, the burning-point of water-gas is 400 DEG C,
Using flue gas by gas-preheating to less than 350 DEG C.The preheating to combustion air can be played to the preheating of combustion gas
Similar effect.
S2, make to be burnt with combustion gas in the feeding stove of the combustion air after being preheated.
As described above, combustion gas and combustion air while reversing combustion, because combustion gas mixes abundant (example with combustion air
Burner as shown in by Fig. 3 is mixed), thus the root of flame can be directly in the exit of burner
Formed.
S3, during burning and carrying out, according to the temperature of burner hearth in stove, produce medium temperature,
Or the pressure of steam, the conveying capacity of regulating gas.
When industrial furnace or civil boiler are used to produce, on the one hand for melt raw material, on the other hand it is used to give birth to
Producing steam is as power.In this step, can be controlled according to the different parameter of the different choice of application to combustion
The regulation of gas conveying capacity.Specifically, in the case of for melt raw material, as shown in figure 4, settable temperature
Degree sensor is used for the temperature for measuring burner hearth or the temperature for producing medium.On the other hand, for producing steam
In the case of, as shown in figure 5, settable pressure sensor is used for the pressure for measuring steam.
The essence of the conveying capacity of regulating gas is, according to the difference of production, foundation temperature or pressure parameter are certainly
Dynamic control combustion gas enters the flow of stove or burner so that combustion reaction heat increaseds or decreases, and is controlled parameter
(for example, pressure of the temperature of burner hearth, the temperature of production medium or steam etc.) convergence manufacturing technique requirent
Parameter.
In this step, can use regulatory PID control algorithm and inertia parameter comparison control algolithm both
Algorithm carrys out the conveying capacity of regulating gas.
For regulatory PID control algorithm, in the process of implementation, step S3 is specifically included：S31, firing
During burning into row, the temperature of burner hearth is measured in real time, produces the temperature of medium or the pressure of steam, and
Using measurement result as process variables；S32, according to manufacturing technique requirent to the temperature of burner hearth, production
The temperature of medium or the pressure sets target pre-set parameter of steam, joined according to process variables, target
Number setting value, combustion gas target conveying capacity is determined using pid control algorithm；S33, regulating gas conveying capacity make
It is equal to combustion gas target conveying capacity.
The principle of PID control is based on below equation, wherein, output M (t) is proportional, integral term and micro-
The function of subitem：
Output=proportional+integral term+differential term
M (t)=KC*e+KC*∫t e dt+Minitial+KC* de/dt, wherein, M (t) exports for loop
(function of time)；KC, can be according to control situation setting ratio for loop gain；E is loop deviation,
That is the difference e=SETconPARA-ProcessVarible of target component setting value and process variables；
MinitialFor the initial value of loop output.
In steady-state operation, by pid control algorithm, Reasonable adjustment ratio K, integration and derivative time,
Flow is controlled by control valve, or fuel gas transmission amount is controlled by adjusting VFD transfer rates, makes deviation (e)
It is zero, it is identical with target component setting value to reach process variables, i.e. regulating gas conveying capacity makes it
Equal to combustion gas target conveying capacity.
In different stoves or boiler combustion process, with the state change of production medium, the quilt of medium is produced
It is not linear to control parameter, and transition or stage jumping characteristic are larger, then with above-mentioned PID control
Algorithm will be unable to respond or control the stability of controlled parameter.Therefore, the control of inertia parameter comparison can be used to calculate
Method, can be according to the variation characteristic of controlled parameter, in the case where procedure parameter is higher than setting value, if process is joined
Number then successively decreases fuel flow rate in ascent stage, and fuel flow rate is constant if the decline stage is in；Join in process
In the case that number is less than setting value, fuel flow rate is constant if procedure parameter is in ascent stage, if being in down
Depression of order section is incremented by.
For inertia parameter comparison control algolithm, in the process of implementation, step S3 is specifically included：
S31, burn carry out during, in real time measure burner hearth temperature, produce medium temperature or
The pressure of steam, and using measurement result as process variables.
S32, temperature, the temperature of production medium or the pressure of steam according to manufacturing technique requirent to burner hearth
Sets target pre-set parameter, and during burning is carried out stage by stage, institute in each stage is judged respectively
State whether process variables are higher than the target component setting value, if so, then enter step S33Y, if
It is no, then into step S33N.
S33Y, judge that the process variables are rising or decline in former and later two stages, if
Decline, then maintain fuel gas transmission amount constant, if rising, then the fuel gas transmission amount is successively decreased predetermined amplitude.
Arthmetic statement is：If process variable ProcessVarible>During setting value SETconPARA；
Then will on last stage the process values lastProVarible of (△ T) with current ProcessVarible pairs
Than judging that current ProcessVarible compared to lastProVarible is rising or decline；Under if
Drop, then fuel transmission ＆ distribution amount is constant, if rising, then can successively decreasing 0.5%, (this decrement can have as needed
Body determines amplitude), wherein △ T refer to the time interval of the front and rear detection of process values, can be according to different stoves
Or boiler is set in 30s-120s scopes.
S33N, judge that the process variables are rising or decline in former and later two stages, if
Rise, then maintain fuel gas transmission amount constant, if declining, then the fuel gas transmission amount is incremented by predetermined amplitude.
Arthmetic statement is：If process variable ProcessVarible<During setting value SETconPARA；
Then will on last stage the process values lastProVarible of (△ T) with current ProcessVarible pairs
Than judging that current ProcessVarible compared to lastProVarible is rising or decline；On if
Rise, then maintain fuel delivery constant, if declining, then can be incremented by 0.5%.
By the operation control being repeated in S32, S33Y or S33N, finally reach controlled parameter
The demand of technique.
S4, during burning and carrying out, oxygen content in flue gas, dynamically adjust combustion air
Flow.
, also can be before step S3 herein it should be noted that step S4 can be performed after step s 3
Perform, two steps can also perform simultaneously.Fig. 6 is that the oxygen content in flue gas dynamically adjusts combustion air
Flow schematic diagram.
Combustion system performance is the most critical part of whole stove or boiler.Existing traditional burner air-fuel ratio
It is fixed air-fuel ratio：A kind of is the flow for being controlled according to the ratio of gaseous-pressure combustion air, and another kind is
According to combustion gas and both valve mechanical chain fixed proportion switches of combustion air.Fixed air-fuel ratio is typically divided
Large, medium and small third combustion intensity flame.The advantages of fixed air-fuel ratio, is stabilization, after having debugged no longer
Needing manually to go to pay close attention to air-fuel ratio, its shortcoming is can not to meet that continuity is adjusted, and due to Different climate ring
Under border, in air there is fluctuation in the composition such as oxygen content and humidity, and fixed air-fuel ratio will not respond in difference
Climatic environment and adjust, its efficiency of combustion can be relatively low.
Therefore, proposed by the present invention is the dynamic air-fuel ratio of anaerobism burning.The burning of so-called anaerobism, be relative to
For oxygen-enriched combusting, simply combustion air is not excessive, and the combustion gas do not burnt also has in air-flow is formed
Very strong oxytropism, can be with remaining oxygen in burner hearth continuing with until completely burned, thus did not had
Surplus air, and fuel heat is measured with whole releases.
In addition, in the past, in combustion process is debugged, many combustion enginnerings teacher think that flame combustion is fiery and forthright,
Then combustion efficiency is good, and such case belongs to obvious oxygen-enriched combusting, although fuel is abundant reactive combustion, heat
Amount also all release, still, excessive air can take away a part of heat and produce excessive pollutant NOx.
Meanwhile oxygen-enriched combusting also shortens the combustion process time so that flame forms shorter, is unfavorable for air-flow shape
Into heat transfer, and shock melting speed is high, and energy resource consumption is big, and burn out rate is high.
In the present invention, burning effect is calculated with the ratio according to the oxygen content remained in smoke evacuation, monitoring gas flow
Rate, body of heater once export exhaust gas temperature (peak, being efficiency of combustion maximum), carry out automatic positive and negative anti-
Feedback, oxygen content in exhaust smoke now is optimum value, then adjusts the ratio of combustion air in real time according to oxygen content in exhaust smoke.
In implementation process, step S4 is specifically included：
S41, during burning and carrying out, air pressure, temperature and the humidity of the outer air of measurement stove.
In order to determine the composition of air under specific climatic environment, barometric pressure sensor can be installed, humiture passes
Sensor, to measure the air pressure of air outside stove, temperature T and humidity rH%.
S42, according to the air pressure of air, temperature, humidity and the conveying capacity of combustion gas outside stove, it is determined that most
Low combustion-supporting wind flow.
According to S41 measurement result, saturated vapour pressure table, obtains saturated vapour pressure corresponding to lookup
(pressure of saturated pure water, its unit are Pa), i.e.,：
Pws=en, e is natural constant 2.71828, n=-5800.2/Tk+1.3914993-
0.048640*Tk+0.00004176*Tk2+ 6.5459673*LN (Tk), Tk are kelvin degree, and LN is
Natural logrithm.
Partial pressure (partial pressure of water moist air, its list of water vapour can further be calculated
Position is Pa) Pw=Pws*rH%；
Further, the partial pressure of dry air is Pa-Pw, the partial pressure of oxygen is 21%* (Pa-Pw),
The ratio of oxygen mole (volume) is 21%* (Pa-Pw)/Pa；
Further according to fuel combustion formula, CmHn+ (m+n/4) O2+ 3.76* (m+n/4) * N2=m
CO2+3.763.76*(m+n/4)*N2+n/2*H2O (CmHn simply represents this fuel of natural gas, other
The equation of fuel is similar).
Fuel flow rate Q1 is determined by fuel flow meter, moreover, counting Q1*O by flow2Quantity
(m+n/4) minimum combustion-supporting wind flow Q2=Q1* (m+n/4)/(21%* (Pa-Pw)/Pa) can, be calculated.
S43, the lower limit value according to minimum combustion-supporting wind flow, adjusting the flow of combustion air makes it in default model
Minimum combustion-supporting wind flow is approached in enclosing.
Mass air flow sensor can be installed in combustion air suction inlet, the flow of combustion air is measured by mass air flow sensor.
S44, the oxygen content in flue gas, cigarette is further adjusted so as to the flow of combustion air
Oxygen content in gas tends to preset value.
Oxygen content in exhaust smoke sensor can be installed on smoke discharging pipe, for detecting the oxygen content in flue gas.Oxygen content
Preset value can be for example configured according to experimental data and actual conditions so that its corresponding highest burning effect
Rate.
It is above-mentioned to be illustrated respectively to adjusting combustion-supporting wind flow according to two kinds of algorithms.In addition, it is necessary to explanation
It is that in combustion, it is permanent with burner hearth that the burner hearth temperature rise period can be divided into according to the situation of temperature change in burner hearth
Thermophase, accordingly, the regulative mode of combustion-supporting wind flow are divided into temperature rise period regulative mode and adjusted with the constant temperature stage
Section mode.Here, briefly explain its control logic.
1st, the temperature rise period at initial stage, gas valve, regulating gas quantity delivered, according to following are controlled by fire box temperature
Temperature rise period regulative mode adjusts the flow of combustion air；
2nd, exhaust gas temperature control commutating period, general commutation cycle are the 90-120 seconds, and exhaust gas temperature control exists
Between 120 DEG C~135 DEG C scopes, the forced commutation if exhaust gas temperature is more than 135 DEG C；
3rd, furnace pressure is maintained at 25Pa or so and is preferred, and passes through the stable stove of the exhaust smoke level of VFC air-introduced machine
Gun pressure power；
4th, treat that fire box temperature rises to the stabilization sub stage, solid material is changed to be controlled by melt temperature after all melting
Fuel feed, and according to the flow of following constant temperature stage regulative modes regulation combustion air.
Temperature rise period regulative mode is described as follows.
In the burner hearth temperature rise period, fire box temperature is less than temperature during burner hearth stable state combustion, fuel and combustion-supporting gas it
Between physical-chemical reaction speed it is slow, moved between molecule it is inviolent, it is necessary to O2Concentration ratio stable state combustion
It is slightly higher under state, be so just advantageous to completely burned.
The burner hearth temperature rise period burns by maximum fuel flow, i.e., fuel quantity is constant, the speed of fire box temperature change
△ T/S, which reach, to be most worth, and this is most worth by the record value as best combustion efficiency.Pass through formula fitting oxygen content
Control function, the oxygen content percentage that can be calculated, contrast the real-time output valve of oxygen-containing quantity sensor.
Specifically, in the burner hearth temperature rise period, the flow of the combustion air is altered in steps, and record fire box temperature
The oxygen content when speed of change takes maximum in corresponding flue gas；The flow of regulation combustion air causes current cigarette
Corresponding oxygen content when the speed that oxygen content in gas tends to fire box temperature change takes maximum, it is included such as
Lower step：
A:The speed △ T/S of fire box temperature change are recorded automatically using controller, in time interval/temperature section
It is interior, by adjusting the blower fan frequency VFD of combustion-supporting air-valve or air-supply, combustion air volume is altered in steps, typing takes
Oxygen content percentage corresponding to maximum △ T/S；
B:In next temperature rise/time interval section, identically with step A, record takes maximum △ T/S
When corresponding oxygen content percentage；
C:List Function Format O2%=f (t), using curve matching, form 3 order polynomial functions
O2PRO%=At3+Bt2+Ct+D
So,, can be with according to the calculating oxygen content in exhaust smoke percentage of above-mentioned function in the corresponding temperature rise period
Adjusting actual air output makes the oxygen-containing ratio of actual smoke evacuation level off to calculated value, realizes abundant in the temperature rise period
Burning, obtains optimal efficiency of combustion and heat utilization ratio.
Constant temperature stage regulative mode is described as follows.
In the burner hearth constant temperature stage, because fire box temperature has reached the higher stabilization sub stage, can accelerate to promote burning anti-
Should, excess air coefficient can be further reduced in theory.The flow of this stage fuel can be with production medium
Changes in process parameters and change, but because fire box temperature has reached stable state, therefore perfect condition is：With minimum mistake
Based on surplus air coefficient, combustion reaction heat is consumed by the efficiency highest of production Absorption of Medium, now fuel flow rate
Minimum, corresponding oxygen content in exhaust smoke are also minimum.
Specifically, in the burner hearth constant temperature stage, the conveying capacity of the combustion gas and containing in the flue gas are recorded in real time
Oxygen amount, corresponding oxygen content during the conveying capacity minimum of the combustion gas is determined, will be corresponding during the conveying capacity minimum
Setting optimum value of the oxygen content as combustion-supporting wind flow in the constant temperature stage, adjust the flow of the combustion air
It is set to approach the setting optimum value, its step is as follows：
A:When producing media technology parameter stability, that is, recept the caloric constant periods, changes air output and changes
Oxygen content in exhaust smoke O2PRO%；
B:The numerical value of record fuel flow rate FLOW changing value and oxygen content in exhaust smoke in real time, in the stream of fuel
When measuring FLOW minimums, the combustion efficiency and heating efficiency highest of fuel；
C:Using corresponding oxygen content in exhaust smoke value during fuel flow rate FLOW minimums in step B, as perseverance
Thermophase air output adjustment control sets optimum value.
Constant temperature stage regulative mode can apply the 3e of Shenzhen Shanneng Technology Co., Ltd.SM- T11 furnace energy-savings
Programmable controller, it is as follows to calculate optimal oxygen content in exhaust smoke algorithm：
So in the steady-state process of burner hearth, with EFFICIAL_O2PRO value is as regulation air output
Setting value.
Meanwhile to prevent from controlling air output mistake occur, should be according to the flow rate calculation air mass flow Q of fuel2,
The limitation scope of excess air coefficient：Minimum excess air coefficient á=1.05, i.e. minimum air mass flow are (low
Limit value) 1.05XQ2, high limit á=1.25, i.e. highest limit air mass flow 1.3X Q2.
So different climate regulations, the oxygen-containing ratio change in humid air, is not with fixed gas valve opening
Degree determines the burning of combustion air aperture, but each stage is combustion-supporting with best combustion and efficiency of utilization regulation
Wind matches somebody with somebody specific discharge, is referred to as " dynamic air-fuel ratio " control burning.
In the furnace efficiency of combustion control method of the present invention, because combustion air is with gas proportioning and mixing it
Waste heat preheating in the preceding flue gas discharged from furnace, it is thus possible to improve fume afterheat utilization rate, separately
Outside, during progress of burning, according to the temperature of burner hearth, the temperature for producing medium or steaming in stove
The pressure of vapour, the conveying capacity of regulating gas, always according to the oxygen content in flue gas, dynamically adjust combustion air
Flow, it is thus possible to improve the efficiency of combustion of combustion gas, reduce gas consumption.
Embodiments of the invention are described above in conjunction with accompanying drawing, but the invention is not limited in upper
The embodiment stated, above-mentioned embodiment is only schematical, rather than restricted
, one of ordinary skill in the art is not departing from present inventive concept and right under the enlightenment of the present invention
It is required that under the ambit protected, can also make many forms, these belong to the present invention protection it
It is interior.
Claims (7)
1. a kind of kiln burning efficiency control method, it is characterised in that comprise the following steps：
S1, the combustion air of feeding stove is set to be discharged from the stove with gas proportioning and before mixing
Waste heat preheating in flue gas；
S2, make to be burnt with the combustion gas in the feeding of the combustion air after the being preheated stove；
S3, during burning and carrying out, according to the temperature of burner hearth in the stove, produce the temperature of medium
The pressure of degree or steam, adjust the conveying capacity of the combustion gas；
S4, during burning and carrying out, according to the oxygen content in the flue gas, dynamically described in regulation
The flow of combustion air.
2. according to the method for claim 1, it is characterised in that the stove is provided with multiple be used for
Air mixture and the mixing burner of combustion air, the step S1 are specially：
Combustion air is alternately passed through each mixing burner and be sent into the stove, and arrange the stove
The flue gas gone out corresponds to the combustion air, is alternately sent to each mixing burner and the combustion air is entered
Discharged after row preheating,
After the step S1, methods described also includes：Make the combustion air and the combustion gas alternately
Mixed at each mixing burner.
3. according to the method for claim 1, it is characterised in that the step S3 is specifically included：
S31, burn carry out during, in real time measure burner hearth temperature, produce medium temperature,
Or the pressure of steam, and using measurement result as process variables；
S32, temperature, the temperature of production medium or the pressure of steam according to manufacturing technique requirent to burner hearth
Power sets target pre-set parameter, according to the process variables, the target component setting value, profit
Combustion gas target conveying capacity is determined with pid control algorithm；
S33, regulating gas conveying capacity make it equal to the combustion gas target conveying capacity.
4. according to the method for claim 1, it is characterised in that
S31, during burning and carrying out, the temperature of the medium of measurement production in real time, and by measurement result
As process variables；
S32, the temperature sets target pre-set parameter according to manufacturing technique requirent to production medium, and
During burning is carried out stage by stage, judge whether process variables are higher than described in each stage respectively
The target component setting value, if so, then entering step S33Y, if it is not, then entering step S33N；
S33Y, judge that the process variables are rising or decline in former and later two stages, if
Decline, then maintain fuel gas transmission amount constant, if rising, then the fuel gas transmission amount is successively decreased default width
Degree；
S33N, judge that the process variables are rising or decline in former and later two stages, if
Rise, then maintain fuel gas transmission amount constant, if declining, then the fuel gas transmission amount is incrementally preset width
Degree.
5. according to the method for claim 1, it is characterised in that the step S4 is specifically included：
S41, during burning and carrying out, measure the air pressure of the outer air of the stove, temperature and wet
Degree；
S42, according to the air pressure of air, temperature, humidity and the conveying of the combustion gas outside the stove
Amount, determines minimum combustion-supporting wind flow；
S43, the lower limit value according to the minimum combustion-supporting wind flow, adjusting the flow of the combustion air makes it
The minimum combustion-supporting wind flow is approached within a preset range；
S44, the oxygen content in the flue gas, the flow of the combustion air is further adjusted
To cause the oxygen content in the flue gas to tend to preset value.
6. according to the method for claim 1, it is characterised in that the step S4 is specifically included：
In the burner hearth constant temperature stage, the conveying capacity of the combustion gas and the oxygen content in the flue gas are recorded in real time, really
Corresponding oxygen content during the conveying capacity minimum of the fixed combustion gas, corresponding during by the conveying capacity minimum this is oxygen-containing
The setting optimum value as combustion-supporting wind flow in the constant temperature stage is measured, adjusting the flow of the combustion air approaches it
The setting optimum value.
7. according to the method for claim 1, it is characterised in that the step S4 is specifically included：
In the burner hearth temperature rise period, the flow of the combustion air is altered in steps, and records the speed of fire box temperature change
Oxygen content when rate takes maximum in corresponding flue gas；
The flow of the combustion air is adjusted so that the oxygen content in current flue gas tends to the speed of fire box temperature change
Corresponding oxygen content when rate takes maximum.
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| CN201610330310.9A CN107401923A (en) | 2016-05-18 | 2016-05-18 | Kiln burning efficiency control method |
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| CN201610330310.9A CN107401923A (en) | 2016-05-18 | 2016-05-18 | Kiln burning efficiency control method |
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