CN113669754A - Method and system for determining real-time heat release of fuel at outlet of combustor - Google Patents
Method and system for determining real-time heat release of fuel at outlet of combustor Download PDFInfo
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- CN113669754A CN113669754A CN202110935864.2A CN202110935864A CN113669754A CN 113669754 A CN113669754 A CN 113669754A CN 202110935864 A CN202110935864 A CN 202110935864A CN 113669754 A CN113669754 A CN 113669754A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C7/00—Combustion apparatus characterised by arrangements for air supply
- F23C7/02—Disposition of air supply not passing through burner
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2237/00—Controlling
- F23N2237/24—Controlling height of burner
- F23N2237/26—Controlling height of burner oxygen-air ratio
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2239/00—Fuels
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Abstract
The invention provides a method and a system for determining real-time heat release of fuel at an outlet of a combustor. The method comprises the following steps: acquiring total heat released by complete combustion of CO obtained by combustion of coal with unit amount of a combustor in deep air staged combustion; obtaining the calorific value of carbon dioxide generated by completely burning unit amount of fire coal; and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by the complete combustion of CO obtained by the combustion of the unit amount of the coal and the heat generated by the complete combustion of the unit amount of the coal into the carbon dioxide.
Description
Technical Field
The invention belongs to the technical field of boiler combustion, and particularly relates to a method and a system for determining real-time heat release of fuel at an outlet of a combustor.
Background
The deep air staged combustion technology is a technology developed in the century, and can effectively realize NOxThe emission reduction is generally applied in China. At present, more than 90% of boilers in China complete the transformation of the deep air classification technology, and the safe and reliable application of the deep air classification technology is very important.
Deep air staged combustionThe burning technique is to make burning under deep oxygen-deficient condition to inhibit NOxAnd let NO already generatedxReduction to N2Thereby minimizing NOxThe concentration of (c); then, oxygen supplementation is carried out, so that the subsequent combustion is finished in an oxygen-enriched environment; since the temperature in this region has decreased, newly generated NOxThe amount is very limited and therefore NO as a wholexThe amount of emissions is significantly reduced.
The construction method of the deep air staged combustion technology comprises the following steps:
1) the air is fed in a grading way through a low NOx burner, such as thick-thin separation, air powder coating technology and the like, and a local oxygen-deficient combustion environment is constructed at the outlet of the burner;
2) the method is characterized in that different combustors are matched, air is distributed in a grading manner on the vertical height of a hearth, namely, the air quantity required for combustion is only given in a proportion (the excess coefficient is controlled to be about 0.75-1.0) of 75% -100% in the vicinity of a main combustor (a combustor for feeding pulverized coal), the pulverized coal is subjected to oxygen-deficient combustion in the area remarkably and widely, then, residual air is introduced above the main combustor, and the residual pulverized coal is subjected to complete combustion in the area under the oxygen-enriched condition. Among these, air fed against the main burner area is referred to as overfire OFA (over fire air), and if the overfire OFA is a significant distance from the main burner area, it is referred to as separated overfire sofa (separated over fire air).
The deep air staging technique generally employs separate overfire SOFA, expands the range to near the entire furnace by staged combustion of air, more closely limits the residence time of fuel in the oxygen deficient zone, and lowers the temperature of the oxygen rich zone to a lower level. A typical burner arrangement is now shown in figure 1.
In deep air staged combustion technology, the rational distribution of excess air ratio for two-stage combustion affects NOxKey factors for the effectiveness of emission control:
1) if the excess air coefficient of the main burner zone is too low, the pulverized coal is not easy to ignite, the combustion is unstable, the burnout is poor, the carbon content of fly ash is high, the reducing atmosphere near the main burner is too strong, and under the environmentThe ash melting point is reduced by 100-120 ℃ compared with that in the oxidizing atmosphere, so that the slagging and high-temperature corrosion of the boiler are caused, and the final NO isxThe concentration may also deteriorate;
2) if the main burner air excess factor is too high, the combustion stability of the pulverized coal is reliable, but NO isxThe concentration of the slag is high, and the serious slag bonding of a hearth is caused because the combustion of the main combustion zone is too strong, so that the serious threat is brought to the safe and stable operation of the boiler.
Therefore, the oxygen amount in the combustor area is important for the safe operation and the operation effect of the boiler, and the oxygen amount in the combustor area is not too large or too small, so that the monitoring is important. However, since the flame temperature of the main burner of the furnace chamber is as high as 1300 ℃ or higher and is full of viscous ash particles, no effective monitoring means exists at present. In the prior art, the excess air coefficient of a boiler to a main combustor area is only obtained by opening of a combustor and indirectly depending on final NOxWithout any direct control, for low NOxThe control of combustion technology is very disadvantageous.
From a design perspective, deep air staging low NOxCompared with the traditional combustion technology, the combustion technology has the obvious difference in the heat release behavior of the pulverized coal in the hearth:
1) the oxygen content of the main combustion area of the traditional hearth is sufficient, and the pulverized coal is finely ground; in the traditional combustion technology, about 96% of components of pulverized coal at the outlet of a main combustor can be combusted; slightly higher than 96% when the combustion condition is good, and slightly lower than 96% when the combustion condition is poor; particularly reflecting on the combustible content of fly ash and slag. The height of the flame at the outlet of each burner, i.e. the point in the flame stream torch from which the coal flame is burned at the highest combustion temperature, is usually slightly above the burner outlet;
2) in the deep air classification low NOx combustion technology, although pulverized coal still grinds finely, the composition for instantly finishing combustion at the outlet of a main combustor is far lower than 96 percent due to the serious shortage of oxidant composition for combustion, so the highest point of flame temperature behind the outlet of each combustor is never slightly higher than the position above the outlet of the combustor;
the boiler furnace is a radiation type heat exchange surface, and the flame temperature is very important for the heat exchange of the furnace. The heat release behavior of the pulverized coal entering the boiler is changed greatly, and the heat release behavior is reflected correspondingly in the design of a hearth, unfortunately, the deep air classification low NOx combustion technology is developed too fast, and at present, the traditional design concept can only be applied to carry out corresponding work. To ensure compliance with practice, it is common practice to modify the calculation results by empirical coefficients.
Disclosure of Invention
The invention aims to provide a method and a system for determining real-time heat release of a fuel at an outlet of a combustor, which are used for design calculation and operation control of a hearth.
In order to achieve the above object, in a first aspect, the present invention provides a method for determining a real-time heat release of a burner outlet fuel, wherein the method comprises:
acquiring total heat released by complete combustion of CO obtained by combustion of coal with unit amount of a combustor in deep air staged combustion;
obtaining the calorific value of carbon dioxide generated by completely burning unit amount of fire coal;
and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by the complete combustion of CO obtained by the combustion of the unit amount of the coal and the heat generated by the complete combustion of the unit amount of the coal into the carbon dioxide.
In a second aspect, the present invention also provides a system for determining the real-time heat release of a burner outlet fuel, wherein the system comprises:
a first obtaining module: the device is used for acquiring total heat released by complete combustion of CO obtained by unit-amount coal combustion of a combustor in deep air staged combustion;
a second obtaining module: the system is used for acquiring the calorific value of the carbon dioxide generated by the complete combustion of the unit amount of the coal;
a heat release amount determination module: and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by CO complete combustion obtained by burning the unit amount of the coal and the heat generated by the carbon dioxide obtained by burning the unit amount of the coal.
The technical scheme provided by the invention can well determine the real calorific value of the coal in a certain range of the outlet of the burner of the hearth under the condition of insufficient excess air so as to be used for design calculation and operation control of the hearth. The technical scheme provided by the invention combines the heat release generated by incomplete combustion of the fuel in the furnace with the carbon monoxide CO generated by combustion in the fuel, thereby realizing the determination of the real heat productivity.
Drawings
FIG. 1 is a schematic diagram of deep air staged burner placement and NOx concentration distribution within a furnace.
Fig. 2 is a schematic flow chart of a method for determining a real-time heat release amount of a burner outlet fuel according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a system for determining a real-time heat release amount of a burner outlet fuel according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in detail and completely with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The principles and spirit of the present invention are explained in detail below with reference to several representative embodiments of the invention.
Referring to fig. 2, in order to achieve the above object, the present invention provides a method for determining a real-time heat release amount of a burner outlet fuel, wherein the method comprises:
step S1: acquiring total heat released by complete combustion of CO obtained by combustion of coal with unit amount of a combustor in deep air staged combustion;
step S2: obtaining the calorific value of carbon dioxide generated by completely burning unit amount of fire coal;
step S3: and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by the complete combustion of CO obtained by the combustion of the unit amount of the coal and the heat generated by the complete combustion of the unit amount of the coal into the carbon dioxide.
In one embodiment, the combustor exit fuel real-time heat release is determined based on the following equation:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qaf,net,arThe real-time heat release of the fuel at the outlet of the combustor is kJ/(kg fire coal).
In one embodiment, obtaining the total heat released from complete combustion of CO from burner unit coal combustion in deep air staged combustion comprises:
acquiring the amount of CO obtained by the unit-amount coal combustion of a combustor in the deep air staged combustion;
determining the total heat released by complete combustion of CO obtained by combustion of the unit amount of coal based on the obtained amount of CO obtained by combustion of the unit amount of coal by the combustor in the deep air staged combustion; wherein the content of the first and second substances,
the total heat released by complete combustion of CO per unit amount of coal combustion is determined based on the following formula:
qCO＝mCO·QCO
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; m isCOThe amount of CO obtained by burning coal in unit amount, kg/(kg coal).
In one embodiment, obtaining the total heat released from complete combustion of CO from burner unit coal combustion in deep air staged combustion comprises:
obtaining the share of carbon elements which are formed by burning coal in a burner into CO in deep air staged combustion and carbon elements burnt by the coal;
acquiring the content of carbon element actually burnt by the received base carbon element of the fire coal (namely the content of the base carbon element received by the fire coal and generated chemical reaction in the boiler, namely the content of the carbon element actually burnt in the fuel);
determining the total heat released by complete combustion of CO obtained by combustion of coal with unit amount in the deep air staged combustion based on the share of carbon element which becomes CO by combustion of coal and carbon element mass content which is actually burnt and received by coal;
further, the total heat released by complete combustion of CO per unit amount of coal combustion is determined by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg;
wherein, the obtaining of the proportion of carbon elements which are burnt into CO by the coal fired by the combustor in the deep air staged combustion in the carbon elements burnt by the coal fired by the combustor preferably comprises:
obtaining CO and CO in flue gas generated by coal combustion of combustor in deep air staged combustion2The content of (A);
based on CO and CO in flue gas generated by coal combustion of combustor in deep air staged combustion2Determining the carbon element which is burnt into CO by the coal of the burner in the deep air staged combustion to account for the carbon element burnt by the coal;
for example, the carbon element in deep air staged combustion that the burner burns coal to CO is determined by the following formula:
in the formula, the volume content of CO in the flue gas;
for CO in flue gas2The volume content of (a); r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
wherein, the obtaining of the proportion of carbon elements which are burnt into CO by the coal fired by the combustor in the deep air staged combustion in the carbon elements burnt by the coal fired by the combustor preferably comprises:
acquiring the excess air coefficient of a combustor in deep air staged combustion;
obtaining theoretical dry air quantity;
determining the share of carbon elements in the deep air staged combustion, which are burnt into CO by the burner coal, in the carbon elements burnt by the coal based on the mass content of the carbon elements actually burnt by the coal, the excess air coefficient and the theoretical dry air amount;
for example, when the excess air factor is greater than 1, the carbon element in the deep air staged combustion, which is the CO produced by burning coal in the burner, accounts for 0 in the carbon element burnt in the coal;
for example, when the excess air ratio is not more than 1, the proportion of carbon elements in deep air staged combustion in which burner coal is burned into CO to carbon elements in which coal is burned is determined by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal; r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
theoretical amount of dry air, m3Per kg; λ is the burn rate (e.g., 96%).
In one embodiment, obtaining the total heat released from complete combustion of CO from burner unit coal combustion in deep air staged combustion comprises:
acquiring the excess air coefficient of a combustor in deep air staged combustion;
acquiring the content of carbon element actually burnt from the received fire coal base;
determining the total heat released by complete combustion of CO obtained by burning unit amount of coal based on the excess air coefficient of a combustor in the deep air staged combustion and the mass content of carbon elements received from the coal and actually burnt;
wherein, when the excess air factor is greater than 1, the total heat released by complete combustion of CO obtained by combustion of a unit amount of coal is 0;
when the excess air ratio is not more than 1, the total heat released by complete combustion of CO obtained by combustion of a unit amount of coal is determined by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; alpha is the excess air factor;
wherein the value of k is determined based on the mass content of carbon element actually burnt from the received coal, the excess air coefficient, the combustion rate and the theoretical dry air amount;
determining the value of k based on the mass content of carbon elements actually burnt from received coal, the excess air coefficient, the combustion rate and the theoretical dry air quantity by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal;
theoretical amount of dry air, m3Per kg; λ is the burn rate (e.g., 96%);
the actual combustion heat release of coal under the condition of oxygen deficiency has a great relationship with the excess air coefficient for the coal; the air excess factor means the ratio of the air actually involved in combustion to the air required for complete combustion, with deep air staging to low NOxIt is the basis when the combustion technology is designed, it is the important means of operation control in operation control, also is the control objective, therefore it is feasible to determine the actual heat release of the coal by the excess air factor at the burner outlet; when the optimal technical scheme is used, the k value of the same coal can be regarded as a fixed value, and after the k value is determined, the total heat release amount of the fuel in the hearth along the height direction can be determined according to the optimal technical scheme, so that the optimal technical scheme has important significance on combustion control, air temperature control, steam production control and the like of a boiler.
In one embodiment, the determination of the actual carbon content burned off based on the received coal is based on the following equation:
in the formula, CarThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the percentage of the carbon element mass which is actually burnt off for the coal receiving base is percent.
In one embodiment, the theoretical dry air amount is determined based on the following equation:
in the formula (I), the compound is shown in the specification,
m is theoretical dry air amount (theoretical dry air amount required per kg of coal combustion)3/kg；HarThe mass percentage of the basic hydrogen element received by the fire coal is percent; o isarThe mass content percentage of the oxygen-based element received by the fire coal is percent; sarThe mass percentage of the basic sulfur element received by the fire coal is percent;
the mass percentage of carbon element which is actually burnt off is received by the coal; carThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asIs the mass content of carbon element in the large slagRate,%; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the preferred embodiment requires an on-line instrument for coal quality elemental analysis to be set up in operation, or elemental analysis data results for the design coal type at the design stage.
In one embodiment, the theoretical dry air amount is obtained from the lower calorific value of coal according to the calculation method of economic and technical indexes of thermal power plants DL/904-2015; the method is specifically carried out based on the following formula:
in the formula (I), the compound is shown in the specification,
m is theoretical dry air amount (theoretical dry air amount required per kg of coal combustion)3Per kg; k is a coefficient related to coal types, and the value of K refers to the standard DL/T904-2015 of the power industry; qnet.arThe coal receives a base low heating value kJ/kg.
In one embodiment, the acquisition of the calorific value of carbon dioxide per unit amount of coal completely burned is performed based on the following equation:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe ash content in fly ash accounts for the fuel coalMass fraction of total ash amount,%; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe mass percentage of the received basic ash of the fire coal is percent.
In one embodiment, the acquisition of the calorific value of carbon dioxide per unit amount of coal completely burned is performed based on the following equation:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent; λ is the burn rate (e.g., 96%).
In one embodiment, the excess air ratio of the burner in deep air staged combustion is typically around 0.8-0.9. The air excess factor means the ratio of the air actually involved in combustion to the air required for complete combustion, with deep air staging to low NOxThe combustion technology is the basis when it is designed, and it is an important means of operation control and a control target when the operation control is performed.
In one embodiment, the mass content percentage of the base hydrogen element received by the fire coal, the mass content percentage of the base oxygen element received by the fire coal, the mass content percentage of the base sulfur element received by the fire coal, the mass content percentage of the base carbon element received by the fire coal, the mass content percentage of the base nitrogen element received by the fire coal, the mass content percentage of the base ash received by the fire coal and the mass content percentage of the base ash received by the fire coal are obtained through coal sampling and testing.
In one embodiment, the mass percentage of carbon in fly ash, the mass percentage of carbon in slag, the mass fraction of ash in fly ash to the total ash content of the coal, and the mass fraction of ash in slag to the total ash content of the coal are measured by a loss on ignition method.
In one embodiment, the mass percentage of carbon in fly ash and the mass percentage of carbon in slag are selected according to table 1.
TABLE 1 carbon content of fly ash and cinder under various conditions in long-term operation
In one embodiment, the mass fraction of the ash content in the fly ash to the total ash content of the coal is selected according to table 2, and the mass fraction of the ash content in the slag to the total ash content of the coal is selected.
TABLE 2 boiler Ash to slag ratio recommended by the utility boiler Performance test protocol (GB/T10184-
In one embodiment, the heating value per unit mass of carbon monoxide is 10108 kJ/kg.
Fig. 3 is a block diagram of a structure of a system for determining a real-time heat release amount of burner outlet fuel according to an embodiment of the present invention, as shown in fig. 3, the system including:
the first acquisition module 31: the device is used for acquiring total heat released by complete combustion of CO obtained by unit-amount coal combustion of a combustor in deep air staged combustion;
the second obtaining module 32: the system is used for acquiring the calorific value of the carbon dioxide generated by the complete combustion of the unit amount of the coal;
the heat release amount determination module 33: and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by CO complete combustion obtained by burning the unit amount of the coal and the heat generated by the carbon dioxide obtained by burning the unit amount of the coal.
In one embodiment, the heat release determination module 33 determines the combustor exit fuel real-time heat release based on the following equation:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qaf,net,arThe real-time heat release of the fuel at the outlet of the combustor is kJ/(kg fire coal).
In an embodiment, the first obtaining module 31 includes:
a CO amount acquisition submodule: the device is used for acquiring the amount of CO obtained by the unit-amount coal burning of the burner in the deep air staged combustion;
a first CO heat determination submodule: determining the total heat released by complete combustion of CO obtained by combustion of the unit amount of coal based on the obtained amount of CO obtained by combustion of the unit amount of coal by the combustor in the deep air staged combustion; wherein the content of the first and second substances,
a first CO heat determination submodule: for determining the total heat released by complete combustion of CO per unit coal combustion based on the following formula:
qCO＝mCO·QCO
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; m isCOThe amount of CO obtained by burning coal in unit amount, kg/(kg coal).
In an embodiment, the first obtaining module 31 includes:
a CO fuel coal share acquisition submodule: the method is used for obtaining the share of carbon elements which are burnt into CO by the coal of the combustor in the deep air staged combustion and account for the carbon elements burnt by the coal;
a burning carbon content obtaining submodule: the method is used for acquiring the content of carbon element actually burnt by the received base carbon element of the fire coal (namely the content of the carbon element which is actually burnt in the fuel and is received by the fire coal and is subjected to chemical reaction in a boiler);
a second CO heat determination submodule: the total heat released by complete combustion of CO obtained by combustion of coal with unit amount of a combustor in deep air staged combustion is determined based on the share of carbon elements which are burnt by the coal and are converted into CO by the combustion of the coal and the mass content of the carbon elements which are actually burnt by the coal;
further, the second CO heat determination submodule determines a total heat released by complete combustion of CO per unit amount of coal combustion by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg;
wherein, the CO fuel coal share obtaining submodule preferably comprises:
flue gas composition determination unit: used for obtaining CO and CO in flue gas generated by coal burning of a burner in deep air staged combustion2The content of (A);
first CO coal share determination unit: for CO and CO in flue gas generated by coal combustion of combustor in deep air staged combustion2Determining the carbon element which is burnt into CO by the coal of the burner in the deep air staged combustion to account for the carbon element burnt by the coal;
for example, the first CO coal share determination unit determines the share of carbon elements in deep air staged combustion in which burner coal is burned into CO, to carbon elements in which coal is burned, by the following formula:
in the formula, the volume content of CO in the flue gas;
for CO in flue gas2The volume content of (a); r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
wherein, the CO fuel coal share obtaining submodule preferably comprises:
an excess air ratio obtaining unit: the system is used for acquiring the excess air coefficient of the combustor in the deep air staged combustion;
theoretical dry air amount acquisition unit: for obtaining a theoretical dry air quantity;
second CO coal share determination unit: the mass content of carbon elements actually burnt based on the received coal, the excess air coefficient and the theoretical dry air amount are used for determining the share of the carbon elements burnt into CO by the coal of the combustor in the deep air staged combustion to the carbon elements burnt by the coal;
for example, when the excess air factor is greater than 1, the carbon element in the deep air staged combustion determined by the second CO fired coal share determination unit, which is the carbon element from which the burner fired coal is burned into CO, accounts for 0;
for example, when the excess air factor is not more than 1, the second CO fired coal share determination unit determines the share of the carbon element that the burner fired coal is burned into CO in the deep air staged combustion, as the carbon element that the fired coal is burned, by the following formula:
in the formula, alpha isAir measurement coefficient;
the mass percentage of carbon element which is actually burnt off is received by the coal; r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
theoretical amount of dry air, m3Per kg; λ is the burn rate (e.g., 96%).
In an embodiment, the first obtaining module 31 includes:
an excess air factor acquisition sub-module: the system is used for acquiring the excess air coefficient of the combustor in the deep air staged combustion;
a burning carbon content obtaining submodule: the method is used for acquiring the content of carbon element actually burnt by the received base carbon element of the fire coal (namely the content of the carbon element which is actually burnt in the fuel and is received by the fire coal and is subjected to chemical reaction in a boiler);
a third CO heat determination submodule: the system is used for determining the total heat released by complete combustion of CO obtained by burning unit amount of coal based on the excess air coefficient of a combustor in the deep air staged combustion and the mass content of carbon elements received from the coal and actually burnt;
when the excess air coefficient is larger than 1, the total heat released by complete combustion of CO obtained by combustion of coal with unit amount determined by the third CO heat determination submodule is 0;
when the excess air factor is not greater than 1, the third CO heat determination submodule determines a total heat released by complete combustion of CO per unit amount of coal combustion by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; alpha is the excess air factor;
wherein the value of k is determined based on the mass content of carbon element actually burnt from the received coal, the excess air coefficient, the combustion rate and the theoretical dry air amount;
determining the value of k based on the mass content of carbon elements actually burnt from received coal, the excess air coefficient, the combustion rate and the theoretical dry air quantity by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal;
theoretical amount of dry air, m3Per kg; λ is the burn rate (e.g., 96%).
In one embodiment, the burnt carbon content obtaining submodule obtains the content of carbon element actually burnt based on the received coal based on the following formula:
in the formula, CarThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the percentage of the carbon element mass which is actually burnt off for the coal receiving base is percent.
In one embodiment, the theoretical dry air amount is determined based on the following equation:
in the formula (I), the compound is shown in the specification,
m is theoretical dry air amount (theoretical dry air amount required per kg of coal combustion)3/kg；HarThe mass percentage of the basic hydrogen element received by the fire coal is percent; o isarThe mass content percentage of the oxygen-based element received by the fire coal is percent; sarThe mass percentage of the basic sulfur element received by the fire coal is percent;
the mass percentage of carbon element which is actually burnt off is received by the coal; carThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the preferred embodiment requires an on-line instrument for coal quality elemental analysis to be set up in operation, or elemental analysis data results for the design coal type at the design stage.
In one embodiment, the theoretical dry air amount is obtained from the lower calorific value of coal according to the calculation method of economic and technical indexes of thermal power plants DL/904-2015; specifically, the theoretical dry air amount is determined based on the following formula:
in the formula (I), the compound is shown in the specification,
m is theoretical dry air amount (theoretical dry air amount required per kg of coal combustion)3Per kg; k is a coefficient related to coal types, and the value of K refers to the standard DL/T904-2015 of the power industry; qnet.arReceiving a base low-grade heating value kJ/kg for the fire coal;
the preferred embodiment requires an on-line instrument for elemental analysis of coal to be provided in operation.
In one embodiment, the second acquisition module 32 acquires the calorific value of the carbon dioxide produced by the complete combustion of the unit amount of coal based on the following formula:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe mass percentage of the received basic ash of the fire coal is percent.
In one embodiment, the second acquisition module 32 acquires the calorific value of the carbon dioxide produced by the complete combustion of the unit amount of coal based on the following formula:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent; λ is the burn rate (e.g., 96%).
In one embodiment, the mass content percentage of the base hydrogen element received by the fire coal, the mass content percentage of the base oxygen element received by the fire coal, the mass content percentage of the base sulfur element received by the fire coal, the mass content percentage of the base carbon element received by the fire coal, the mass content percentage of the base nitrogen element received by the fire coal, the mass content percentage of the base ash received by the fire coal and the mass content percentage of the base ash received by the fire coal are obtained through coal sampling and testing.
In one embodiment, the mass percentage of carbon in fly ash, the mass percentage of carbon in slag, the mass fraction of ash in fly ash to the total ash content of the coal, and the mass fraction of ash in slag to the total ash content of the coal are measured by a loss on ignition method.
In one embodiment, the heating value per unit mass of carbon monoxide is 10108 kJ/kg.
Example 1
The embodiment provides a method for determining the real-time heat release of a fuel at the outlet of a combustor, wherein the method comprises the following steps:
step 1: acquiring an excess air coefficient alpha of a combustor in deep air staged combustion;
specifically, the excess air ratio α is 0.85.
Step 2: acquiring the combustion rate lambda of deep air staged combustion;
specifically, the combustion rate λ was 96%.
And step 3: obtaining the mass content of carbon element actually burnt from the received base of the fire coal
Specifically, the coal quality components and ash components of typical coal types in North China (as shown in Table 3) are obtained through coal sampling assay and ignition loss method measurement, and the content of carbon elements actually burnt from received coal base is determined according to the following formula
In the formula, CarThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the percentage of the carbon element mass which is actually burnt off for the coal receiving base is percent.
And 4, step 4: obtaining theoretical dry air quantity
Specifically, the theoretical dry air amount is determined by the following formula
In the formula (I), the compound is shown in the specification,
m is theoretical dry air amount (theoretical dry air amount required per kg of coal combustion)3/kg；HarThe mass percentage of the basic hydrogen element received by the fire coal is percent; o isarThe mass content percentage of the oxygen-based element received by the fire coal is percent; sarThe mass percentage of the basic sulfur element received by the fire coal is percent;
the percentage of the carbon element mass which is actually burnt off for the coal receiving base is percent.
And 5: the k value of a typical coal type in North China is determined by the following formula based on the mass content of carbon elements actually burned in received coal, the excess air coefficient, the combustion rate and the theoretical dry air amount (the result is shown in Table 3):
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal;
theoretical amount of dry air, m3Per kg; λ is the burn rate (e.g., 96%).
TABLE 3
Step 6: determining total heat q released by complete combustion of CO obtained by burning unit amount of coal based on excess air coefficient of burner in deep air staged combustion and mass content of carbon element actually burnt based on coal yieldCO；
In the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide of unit mass is 10108 kJ/kg; alpha is the excess air factor; k is the value determined in step 5.
And 7: obtaining the heat productivity of carbon dioxide generated by the complete combustion of unit amount of coal
In the formula (I), the compound is shown in the specification,
heating of carbon dioxide for complete combustion of a unit quantity of coalAmount, kJ/(kg coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe mass percentage of the received basic ash of the fire coal is percent.
And 8: determining the real-time heat release Q of the fuel at the outlet of the combustor based on the obtained total heat released by the complete combustion of CO obtained by the combustion of the unit amount of coal and the heat generated by the complete combustion of the unit amount of coal into carbon dioxideaf,net,ar；
In the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qaf,net,arThe real-time heat release of the fuel at the outlet of the combustor is kJ/(kg fire coal); carThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the percentage of the carbon element mass which is actually burnt off for the coal receiving base is percent.
The calculated k value was 2.3, the industrial analysis data are shown in the coal of Table 4, the real-time heat release when the excess air ratio alpha was 0.85 and the combustion rate lambda was 96%
TABLE 4
The calculated real-time heat release of the oxygen-deficient combustion is 15947 kJ/kg.
The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. The many features and advantages of the embodiments are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the embodiments which fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the embodiments of the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope thereof.
The principle and the implementation mode of the invention are explained by applying specific embodiments in the invention, and the description of the embodiments is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (18)
1. A method of determining a real-time heat release of a combustor exit fuel, wherein the method comprises:
acquiring total heat released by complete combustion of CO obtained by combustion of coal with unit amount of a combustor in deep air staged combustion;
obtaining the calorific value of carbon dioxide generated by completely burning unit amount of fire coal;
and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by the complete combustion of CO obtained by the combustion of the unit amount of the coal and the heat generated by the complete combustion of the unit amount of the coal into the carbon dioxide.
2. The determination method according to claim 1, wherein acquiring the total heat released by complete combustion of CO from burner unit coal combustion in deep air staged combustion comprises:
acquiring the excess air coefficient of a combustor in deep air staged combustion;
acquiring the content of carbon element actually burnt from the received fire coal base;
determining the total heat released by complete combustion of CO obtained by burning unit amount of coal based on the excess air coefficient of a combustor in the deep air staged combustion and the mass content of carbon elements received from the coal and actually burnt;
wherein, when the excess air factor is greater than 1, the total heat released by complete combustion of CO obtained by combustion of a unit amount of coal is 0;
when the excess air ratio is not more than 1, the total heat released by complete combustion of CO obtained by combustion of a unit amount of coal is determined by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; alpha is the excess air factor;
wherein the value of k is determined based on the mass content of carbon element actually burnt from the received coal, the excess air coefficient, the combustion rate and the theoretical dry air amount;
determining the value of k based on the mass content of carbon elements actually burnt from received coal, the excess air coefficient, the combustion rate and the theoretical dry air quantity by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal; va 0Theoretical amount of dry air, m3Per kg; λ is a combustion rate.
3. The determination method according to claim 1, wherein acquiring the total heat released by complete combustion of CO from burner unit coal combustion in deep air staged combustion comprises:
obtaining the share of carbon elements which are formed by burning coal in a burner into CO in deep air staged combustion and carbon elements burnt by the coal;
acquiring the content of carbon element actually burnt from the received fire coal base;
determining the total heat released by complete combustion of CO obtained by combustion of coal with unit amount in the deep air staged combustion based on the share of carbon element which becomes CO by combustion of coal and carbon element mass content which is actually burnt and received by coal;
preferably, the total heat released by complete combustion of CO per unit amount of coal fired combustion is determined by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg.
4. The determination method according to claim 3, wherein acquiring a share of carbon elements in deep air staged combustion that are burned into CO by burner coal, in carbon elements burned by coal, comprises:
obtaining CO and CO in flue gas generated by coal combustion of combustor in deep air staged combustion2The content of (A);
based on CO and CO in flue gas generated by coal combustion of combustor in deep air staged combustion2Determining the carbon element which is burnt into CO by the coal of the burner in the deep air staged combustion to account for the carbon element burnt by the coal;
preferably, the proportion of carbon elements in deep air staged combustion that are burnt by burner coal to CO to carbon elements that are burnt by coal is determined by the following formula:
in the formula, the volume content of CO in the flue gas;
for CO in flue gas2The volume content of (a); r isCOThe carbon element that forms CO for the combustion of the coal accounts for the portion of the carbon element combusted for the coal.
5. The determination method according to claim 3, wherein acquiring a share of carbon elements in deep air staged combustion that are burned into CO by burner coal, in carbon elements burned by coal, comprises:
acquiring the excess air coefficient of a combustor in deep air staged combustion;
obtaining theoretical dry air quantity;
determining the share of carbon elements in the deep air staged combustion, which are burnt into CO by the burner coal, in the carbon elements burnt by the coal based on the mass content of the carbon elements actually burnt by the coal, the excess air coefficient and the theoretical dry air amount;
preferably, when the excess air factor is more than 1, the carbon element which is burnt into CO by the coal of the combustor in the deep air staged combustion accounts for 0 part of the carbon element burnt by the coal;
preferably, when the excess air ratio is not more than 1, the proportion of carbon elements in deep air staged combustion in which the burner coal is burned into CO to carbon elements in which the coal is burned is determined by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal; r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
theoretical amount of dry air, m3Per kg; λ is a combustion rate.
6. The determination method according to claim 1, wherein acquiring the total heat released by complete combustion of CO from burner unit coal combustion in deep air staged combustion comprises:
acquiring the amount of CO obtained by the unit-amount coal combustion of a combustor in the deep air staged combustion;
determining the total heat released by complete combustion of CO obtained by combustion of the unit amount of coal based on the obtained amount of CO obtained by combustion of the unit amount of coal by the combustor in the deep air staged combustion; wherein the content of the first and second substances,
the total heat released by complete combustion of CO per unit amount of coal combustion is determined based on the following formula:
qCO＝mCO·QCO
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; m isCOThe amount of CO obtained by burning coal in unit amount, kg/(kg coal).
7. The determination method according to claim 2 or 3, wherein the obtaining of the content of carbon element actually burned off based on the coal receipt is performed based on the following formula:
in the formula, CarThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the percentage of the carbon element mass which is actually burnt off for the coal receiving base is percent.
8. The determination method according to claim 2 or 5, wherein the dry air amount is performed based on the following formula:
in the formula, Va 0Theoretical amount of dry air, m3/kg；HarThe mass percentage of the basic hydrogen element received by the fire coal is percent; o isarThe mass content percentage of the oxygen-based element received by the fire coal is percent; sarThe mass percentage of the basic sulfur element received by the fire coal is percent;
the mass percentage of carbon element which is actually burnt off is received by the coal; carThe mass percentage of the carbon element received by the fire coal is percent; cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the theoretical dry air amount is based on the following formula:
in the formula (I), the compound is shown in the specification,
theoretical amount of dry air, m3Per kg; k is related to coal types, and the value of K refers to the standard DL/T904-2015 of the power industry; qnet.arThe coal receives a base low heating value kJ/kg.
9. The determination method of claim 1, wherein the combustor exit fuel real-time heat release is determined based on the following equation:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qaf,net,arThe real-time heat release of the fuel at the outlet of the combustor is kJ/(kg fire coal).
10. The determination method according to claim 1,
the heat value of carbon dioxide obtained by completely burning a unit amount of coal is obtained based on the following formula:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the heat value of carbon dioxide obtained by completely burning a unit amount of coal is obtained based on the following formula:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent; λ is a combustion rate.
11. A system for determining real-time heat release of a combustor exit fuel, wherein the system comprises:
a first obtaining module: the device is used for acquiring total heat released by complete combustion of CO obtained by unit-amount coal combustion of a combustor in deep air staged combustion;
a second obtaining module: the system is used for acquiring the calorific value of the carbon dioxide generated by the complete combustion of the unit amount of the coal;
a heat release amount determination module: and determining the real-time heat release amount of the fuel at the outlet of the combustor based on the obtained total heat released by CO complete combustion obtained by burning the unit amount of the coal and the heat generated by the carbon dioxide obtained by burning the unit amount of the coal.
12. The system of claim 11, wherein the first acquisition module comprises:
an excess air factor acquisition sub-module: the system is used for acquiring the excess air coefficient of the combustor in the deep air staged combustion;
a burning carbon content obtaining submodule: the method is used for acquiring the content of carbon element actually burnt from the received fire coal base;
a third CO heat determination submodule: the system is used for determining the total heat released by complete combustion of CO obtained by burning unit amount of coal based on the excess air coefficient of a combustor in the deep air staged combustion and the mass content of carbon elements received from the coal and actually burnt;
when the excess air coefficient is larger than 1, the total heat released by complete combustion of CO obtained by combustion of coal with unit amount determined by the third CO heat determination submodule is 0;
when the excess air factor is not greater than 1, the third CO heat determination submodule determines a total heat released by complete combustion of CO per unit amount of coal combustion by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; alpha is the excess air factor;
wherein the value of k is determined based on the mass content of carbon element actually burnt from the received coal, the excess air coefficient, the combustion rate and the theoretical dry air amount;
determining the value of k based on the mass content of carbon elements actually burnt from received coal, the excess air coefficient, the combustion rate and the theoretical dry air quantity by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal;
theoretical amount of dry air, m3Per kg; λ is a combustion rate.
13. The system of claim 11, wherein the first acquisition module comprises:
a CO fuel coal share acquisition submodule: the method is used for obtaining the share of carbon elements which are burnt into CO by the coal of the combustor in the deep air staged combustion and account for the carbon elements burnt by the coal;
a burning carbon content obtaining submodule: the method is used for acquiring the content of carbon element actually burnt from the received fire coal base;
a second CO heat determination submodule: the total heat released by complete combustion of CO obtained by combustion of coal with unit amount of a combustor in deep air staged combustion is determined based on the share of carbon elements which are burnt by the coal and are converted into CO by the combustion of the coal and the mass content of the carbon elements which are actually burnt by the coal;
preferably, the second CO heat determination submodule determines the total heat released by complete combustion of CO per unit quantity of coal burned by the following formula:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
the mass percentage of carbon element which is actually burnt off is received by the coal; qCOThe calorific value of carbon monoxide per unit mass, kJ/kg.
14. The system of claim 13, wherein the CO fire coal share acquisition sub-module comprises:
flue gas composition determination unit: used for obtaining CO and CO in flue gas generated by coal burning of a burner in deep air staged combustion2The content of (A);
first CO coal share determination unit: for CO and CO in flue gas generated by coal combustion of combustor in deep air staged combustion2Determining the carbon element which is burnt into CO by the coal of the burner in the deep air staged combustion to account for the carbon element burnt by the coal;
preferably, the first CO fire coal share determination unit determines the share of carbon elements in deep air staged combustion in which burner fire coal is burned into CO, to carbon elements in which the fire coal is burned, by the following formula:
in the formula, the volume content of CO in the flue gas;
for CO in flue gas2The volume content of (a); r isCOThe carbon element that forms CO for the combustion of the coal accounts for the portion of the carbon element combusted for the coal.
15. The system of claim 13, wherein the CO fire coal share acquisition sub-module comprises:
an excess air ratio obtaining unit: the system is used for acquiring the excess air coefficient of the combustor in the deep air staged combustion;
theoretical dry air amount acquisition unit: for obtaining a theoretical dry air quantity;
second CO coal share determination unit: the mass content of carbon elements actually burnt based on the received coal, the excess air coefficient and the theoretical dry air amount are used for determining the share of the carbon elements burnt into CO by the coal of the combustor in the deep air staged combustion to the carbon elements burnt by the coal;
preferably, when the excess air factor is greater than 1, the carbon element in the deep air staged combustion determined by the second CO fired coal share determination unit, which is burned into CO by the burner fired coal, accounts for 0 in the share of the carbon element burned by the fired coal;
preferably, when the excess air factor is not more than 1, the second CO fired coal share determining unit determines the share of the carbon element that the burner fired coal is burned into CO in the deep air staged combustion to the carbon element that the fired coal is burned by the following formula:
wherein α is an excess air factor;
the mass percentage of carbon element which is actually burnt off is received by the coal; r isCOThe carbon element for burning the fire coal into CO accounts for the part of the carbon element burnt by the fire coal;
theoretical amount of dry air, m3Per kg; λ is a combustion rate.
16. The system of claim 11, wherein the first acquisition module comprises:
a CO amount acquisition submodule: the device is used for acquiring the amount of CO obtained by the unit-amount coal burning of the burner in the deep air staged combustion;
a first CO heat determination submodule: determining the total heat released by complete combustion of CO obtained by combustion of the unit amount of coal based on the obtained amount of CO obtained by combustion of the unit amount of coal by the combustor in the deep air staged combustion; wherein the content of the first and second substances,
a first CO heat determination submodule: for determining the total heat released by complete combustion of CO per unit coal combustion based on the following formula:
qCO＝mCO·QCO
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal); qCOThe calorific value of carbon monoxide per unit mass, kJ/kg; m isCOThe amount of CO obtained by burning coal in unit amount, kg/(kg coal).
17. The system of claim 11, wherein the heat release determination module determines the combustor exit fuel real-time heat release based on the following equation:
in the formula, qCOThe total heat released by complete combustion of CO obtained by combustion of unit amount of coal, kJ/(kg coal);
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qaf,net,arThe real-time heat release of the fuel at the outlet of the combustor is kJ/(kg fire coal).
18. The system of claim 11, wherein,
the second acquisition module acquires the calorific value of carbon dioxide generated by the complete combustion of unit coal based on the following formula:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent;
the second acquisition module acquires the calorific value of carbon dioxide generated by the complete combustion of unit coal based on the following formula:
in the formula (I), the compound is shown in the specification,
the calorific value of carbon dioxide generated by the complete combustion of unit amount of coal is kJ/(kg of coal); qnet.arThe coal receives basic low-level heating value kJ/(kg coal); cf,asIs the mass percentage of carbon element in the fly ash; cs,asThe mass percentage of carbon element in the large slag is percent; r isf,asThe mass percentage of the ash in the fly ash to the total ash of the fire coal is percent; r iss,asThe mass percentage of the ash in the large slag to the total ash of the fire coal is percent; a. thearThe percentage of the mass content of the received base ash of the fire coal is percent; λ is a combustion rate.
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2021
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| US3939653A (en) * | 1974-03-29 | 1976-02-24 | Phillips Petroleum Company | Gas turbine combustors and method of operation |
| US5350293A (en) * | 1993-07-20 | 1994-09-27 | Institute Of Gas Technology | Method for two-stage combustion utilizing forced internal recirculation |
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| CN104992021A (en) * | 2015-07-10 | 2015-10-21 | 华北电力科学研究院有限责任公司 | Method and apparatus for determining calculated fuel quantity |
| CN111306533A (en) * | 2019-04-29 | 2020-06-19 | 上海交通大学 | Low NOx control method for staged combustion air depth staged combustion of coal-fired boiler |
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