阅读说明：本技术 检测燃煤耦合生物质燃烧中生物质热量份额的系统和方法 (System and method for detecting biomass heat share in coal-fired coupled biomass combustion ) 是由 袁建丽 张怀宇 李璟涛 周乃康 符佳 戴碧艳 吴水木 于 2020-05-31 设计创作，主要内容包括：本发明公开了一种检测燃煤耦合生物质燃烧中生物质热量份额的方法和系统,所述方法包括在锅炉中仅燃烧燃煤、仅燃烧生物质和耦合燃烧燃煤和生物质三种情况下在锅炉尾部分别测量烟气中的氧气含量和二氧化碳含量,并分别得出三种情况下基于标准氧量的二氧化碳含量,根据三种情况下基于标准氧量的二氧化碳含量计算燃煤和生物质耦合燃烧时输入锅炉的生物质的热量份额R。本发明的检测燃煤耦合生物质燃烧中生物质热量份额的方法相对简单,可以相对准确地获得燃煤耦合生物质燃烧中生物质热量的份额。(The invention discloses a method and a system for detecting biomass heat share in coal-fired coupled biomass combustion, wherein the method comprises the steps of respectively measuring the oxygen content and the carbon dioxide content in flue gas at the tail part of a boiler under three conditions of only burning coal, only burning biomass, coupled burning coal and biomass in the boiler, respectively obtaining the carbon dioxide content based on standard oxygen amount under the three conditions, and calculating the heat share R of biomass input into the boiler during the coal-fired and biomass coupled combustion according to the carbon dioxide content based on the standard oxygen amount under the three conditions. The method for detecting the biomass heat share in the combustion of the coal-fired coupled biomass is relatively simple, and the biomass heat share in the combustion of the coal-fired coupled biomass can be relatively accurately obtained.)

1. A method for detecting biomass heat share in coal-fired coupled biomass combustion is characterized by comprising the following steps:

burning only the fire coal in the boiler, and measuring the oxygen content and the carbon dioxide content in the flue gas at the tail of the boiler respectively, and recording as VO₂1 and VCO₂1；

Only biomass is burned in the boiler, and the oxygen content and carbon dioxide content in the flue gas are measured at the tail of the boiler and recorded as VO respectively₂2 and VCO₂2；

Coupling combustion of coal and biomass in a boiler, and measuring the oxygen content and carbon dioxide content in flue gas at the tail of the boiler, which are respectively recorded as VO₂3 and VCO₂3；

According to VO₂1 and VCO₂1 obtaining the carbon dioxide content based on standard oxygen amount in the flue gas when only burning coal in the boiler, and recording as VCO₂1s；

According to VO₂2 and VCO₂2 obtaining in the flue gas when only biomass is burned in the boilerCarbon dioxide content based on standard oxygen quantity, denoted VCO₂2s；

According to VO₂3 and VCO₂3 obtaining the content of carbon dioxide based on standard oxygen amount in the flue gas when the coal and the biomass are simultaneously combusted in the boiler, and recording the content as VCO₂3s；

The heat share R of biomass input into a boiler during coupled combustion of coal and biomass is obtained according to the following formula (1):

2. the method for detecting biomass heat share in coal-fired coupled biomass combustion as claimed in claim 1, wherein the standard oxygen amount is 6% oxygen amount, wherein the VCO is obtained by the following equations (2), (3) and (4)₂1s、VCO₂2s and VCO₂3s：

3. The method for detecting biomass heat share in coal-fired coupled biomass combustion as claimed in claim 1 or 2, wherein the VO is₂1、VCO₂1、VO₂2、VCO₂2、VO₂3 and VCO₂3 are volume concentrations in the dry state.

4. The method for detecting the biomass heat share in the combustion of the biomass coupled with the fire coal according to claim 3, wherein in the step of coupling and combusting the fire coal and the biomass in the boiler, the lower calorific value and the mass flow of the fire coal are detected and recorded as L HV1 and m1 respectively;

obtaining the heat share R of biomass input into a boiler during coupled combustion of coal and biomass according to the following formula (5)₀：

Comparing R and R₀It is verified whether the error of R obtained by equation (1) meets operational and metering requirements.

5. The method for detecting the biomass heat share in the combustion of the fire coal coupled biomass as claimed in claim 4, wherein the biomass is a reference biomass, the lower calorific value of the reference biomass is L HV2b, and the moisture and ash of the reference biomass are Mar2b and Aar2b respectively;

the moisture and ash of the incoming biomass entering the boiler, when the composition of the incoming biomass deviates from the composition of the reference biomass, are Mar2 and Aar2 respectively,

the low calorific value of the biomass charged into the furnace is L HV2, and

6. a system for detecting biomass heat share in coal-fired coupled biomass combustion for implementing the method of any one of claims 1-5, comprising:

a boiler;

the coal-fired burner is arranged in the boiler and used for burning coal;

the biomass burner is arranged in the boiler, positioned above the coal-fired burner and used for burning biomass;

and the detection device is arranged at the tail part of the boiler and is used for detecting the oxygen content and the carbon dioxide content in the tail flue gas of the boiler when only the fire coal is combusted, only the biomass is combusted and the fire coal and the biomass are combusted in a coupling manner.

7. The system for detecting biomass heat share in coal-fired coupled biomass combustion as claimed in claim 6, wherein the detection device comprises a first detection device and a second detection device, the first detection device is used for detecting the oxygen content in the tail flue gas of the boiler, and the second detection device is used for detecting the carbon dioxide content in the tail flue gas of the boiler.

8. The system for detecting biomass heat share in coal-fired coupled biomass combustion as claimed in claim 7, wherein the first detection device is used for detecting the oxygen volume concentration in the boiler tail flue gas in a dry basis state, and the second detection device is used for detecting the carbon dioxide volume concentration in the boiler tail flue gas in the dry basis state.

9. The system for detecting biomass heat share in coal-fired coupled biomass combustion as claimed in claim 6, further comprising:

the coal pulverizing device is positioned outside the boiler and connected with the coal-fired burner and is used for crushing and pulverizing the coal and supplying the coal into the coal-fired burner;

the first analysis and measurement device is positioned outside the boiler, is connected with the coal pulverizing device and the coal burner and is used for detecting the coal quality component, the low heat value and the mass flow of the coal entering the boiler;

the biomass pulverizing device is positioned outside the boiler and is connected with the biomass burner, and is used for crushing and pulverizing biomass and supplying the biomass into the biomass burner;

and the second analysis metering device is positioned outside the boiler, is connected with the biomass milling device and the biomass burner and is used for detecting the biomass components, the low-level heat value and the mass flow entering the boiler.

10. The system for detecting biomass heat share in coal-fired coupled biomass combustion as claimed in any one of claims 6-9, further comprising an over-fire air nozzle disposed within the boiler and above the biomass burner.

Technical Field

The invention relates to the technical field of energy utilization, in particular to a system and a method for detecting biomass heat share in coal-fired coupled biomass combustion.

Background

Drastic changes in global climate and CO₂The increasing emission of the fuel brings much pressure to the future survival of human beings, and the reduction of the consumption of fossil fuel can reduce CO₂The greenhouse effect is reduced. The energy efficiency of thermal power generation is improved, the usage amount of biomass fuel is increased, and the coal consumption of a coal-fired power plant can be reduced, so that biomass and coal are subjected to coupled combustion, and power generation by using the existing coal-fired boiler and thermal power generation equipment is a shortcut for solving the problems.

Biomass and coal coupled power generation has two forms: direct mixed combustion and gasification combustion. For a direct mixed combustion power generation boiler, because the characteristic difference of biomass fuel is large, particularly the moisture, ash and fuel heat value are easily interfered by objective or subjective factors, the biomass fuel quantity and input heat entering the boiler cannot be measured by using a direct metering method, the biomass power generation share in a coupling generator set cannot be visually distinguished, and government departments and power grid companies are difficult to carry out electricity price subsidy on coupling power generation projects, so that the direct mixed combustion coupling power generation mode cannot be effectively popularized and applied.

Disclosure of Invention

The present application is based on the discovery and recognition by the inventors of the following facts and problems:

Drawings

Fig. 1 is a flow chart of a method of detecting biomass heat share in coal-fired coupled biomass combustion according to an embodiment of the invention.

FIG. 2 is a schematic diagram of a system for detecting biomass heat share in coal-fired coupled biomass combustion according to an embodiment of the invention.

Reference numerals:

boiler 1, coal-fired burner 2, biomass burner 3, detection device 4, first detection device 41, second detection device 42, coal-fired powder process device 5, first analytical metering device 6, biomass powder process device 7, second analytical metering device 8, overfire air nozzle 9, economizer 10, SCR denitrification facility 11, air preheater 12.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

As shown in fig. 1, the method for detecting biomass heat share in coal-fired coupled biomass combustion according to the embodiment of the invention comprises the following steps:

burning only the fire coal in the boiler, and measuring the oxygen content and the carbon dioxide content in the flue gas at the tail of the boiler respectively, and recording as VO₂1 and VCO₂1；

Only biomass is burned in the boiler, and the oxygen content and carbon dioxide content in the flue gas are measured at the tail of the boiler and recorded as VO respectively₂2 and VCO₂2；

Coupling combustion of coal and biomass in a boiler, and measuring the oxygen content and carbon dioxide content in flue gas at the tail of the boiler, which are respectively recorded as VO₂3 and VCO₂3；

According to VO₂1 and VCO₂1 obtaining the carbon dioxide content based on standard oxygen amount in the flue gas when only burning coal in the boiler, and recording as VCO₂1s；

According to VO₂2 and VCO₂2 obtaining the content of carbon dioxide based on standard oxygen amount in the flue gas when only biomass is combusted in the boiler, and recording as VCO₂2s；

According to VO₂3 and VCO₂3 obtaining the content of carbon dioxide based on standard oxygen amount in the flue gas when the coal and the biomass are simultaneously combusted in the boiler, and recording the content as VCO₂3s；

The heat share R of biomass input into a boiler during coupled combustion of coal and biomass is obtained according to the following formula (1):

according to the method for detecting the biomass heat share in the combustion of the coal-fired coupled biomass, the oxygen content and the carbon dioxide content in the tail flue gas of the boiler are respectively detected when only the coal-fired is combusted, only the biomass is combusted and the coal-fired and biomass are coupled and combusted, the biomass heat proportion input into the boiler in the combustion of the coal-fired coupled biomass is calculated by using a formula (1), the measurement and statistics of the biomass power generation amount of a coupled generator set are realized, the method is relatively simple, and the obtained biomass heat share has high accuracy.

In some embodiments, the standard oxygen is 6% oxygen, and the VCO is obtained from equations (2), (3), and (4) below₂1s、VCO₂2s and VCO₂3s：

Thus, when the standard oxygen amount is set to 6% oxygen amount, the carbon dioxide content VCO based on the standard oxygen amount in the flue gas when only the coal is burned in the boiler can be obtained by the above three formulas, respectively₂1s, carbon dioxide content VCO based on standard oxygen amount in flue gas when only biomass is combusted in boiler₂2s and standard oxygen based carbon dioxide content VCO in flue gas during coupled combustion of coal and biomass₂3s。

In some embodiments, VO₂1、VCO₂1、VO₂2、VCO₂2、VO₂3 and VCO₂3 are volume concentrations in the dry state. Thus, the VCO₂1s、VCO₂2s and VCO₂3s are the volume concentrations in the dry state based on the standard oxygen amounts. Wherein the VCO obtained by the formula (2) is adjusted to a standard oxygen content of 6% oxygen₂1s is the carbon dioxide content in the flue gas on a dry basis based on 6% oxygen content when only coal is burned in the boiler, VCO derived from equation (3)₂2s is the carbon dioxide content in the flue gas based on 6% oxygen and in the dry state when only biomass is combusted in the boiler, VCO derived from equation (4)₂3s is the carbon dioxide content in the flue gas based on 6% oxygen and in a dry basis when the coal and biomass are combusted in a coupled manner in the boiler.

In some embodiments, in the step of coupled combustion of the coal and the biomass in the boiler, the lower heating value and the mass flow of the coal are detected and respectively recorded as L HV1 and m 1;

obtaining the heat share R of biomass input into a boiler during coupled combustion of coal and biomass according to the following formula (5)₀：

Comparing R and R₀It is verified whether the error of R obtained by equation (1) meets operational and metering requirements.

In other words, in this example, when only the coal is burned in the boiler, the oxygen content VO in the flue gas is measured separately only at the boiler tail₂1 and carbon dioxide content VCO₂1；

When only biomass is burned in the boiler, the oxygen content VO in the flue gas is measured separately only at the boiler tail₂2 and carbon dioxide content VCO₂2；

When the fire coal and the biomass are combusted in a coupled mode in the boiler, on one hand, the lower heat value L HV1 and the mass flow m1 of the fire coal are detected, and the lower heat value L HV2 and the mass flow m2 of the biomass are monitored, and on the other hand, the oxygen content VO in smoke is respectively measured at the tail part of the boiler₂3 and carbon dioxide content VCO₂3；

Finally, the heat share R of the biomass input into the boiler during the coupled combustion of the coal and the biomass is calculated by formula (1) on the one hand, and the heat share R of the biomass input into the boiler during the coupled combustion of the coal and the biomass is calculated by formula (5) on the other hand₀By comparing R and R₀The error of R obtained from equation (1) is determined and verified to meet operational and metering requirements.

In some embodiments, in the step of burning only the biomass in the boiler, the detected biomass is a reference biomass, the lower heating value of the reference biomass is L HV2b, and the moisture and ash of the reference biomass are Mar2b and Aar2b, respectively;

when the composition of the charged biomass entering the boiler deviates from that of the reference biomass, the moisture and ash of the charged biomass are Mar2 and Aar2, respectively, the lower calorific value of the charged biomass is L HV2, and

in this example, the inventor of the present invention found through research that biomass fuel is subject to variability, and external moisture and ash (ash, inorganic matter, residue after calcination or after drying) are subject to fluctuation, which causes great changes in the lower calorific value and mass flow rate of biomass entering a boiler. In other words, the biomass entering the boiler is changed along with the moisture and ash contained in the biomass, so that the lower calorific value of the biomass is correspondingly changed. It is therefore difficult to meter and analyze the biomass input energy share in coupled power generation. For this reason, a reference biomass is set as a calculation reference to improve accuracy. The reference biomass is a biomass fuel of a certain type, the carbon-hydrogen ratio in the fuel element analysis is relatively fixed, and the moisture, ash and lower calorific value of the fuel are fixed values.

Because the medium moisture and the ash content of the biomass fuel do not generate heat during combustion, the heat mainly comes from carbon and hydrogen elements, once the moisture and the ash content in the reference biomass fuel deviate, the low-order heat value of the biomass fuel can be corrected through a formula (6), meanwhile, when the biomass fuel is combusted in a hearth, the moisture and the ash content deviating from the reference biomass components do not influence the components of dry-based flue gas, and CO in the dry-based flue gas₂The volume concentration depends only on the type of biomass fuel, i.e. the hydrocarbon ratio.

The system for detecting biomass heat share in coal-fired coupled biomass combustion according to the embodiment of the invention is described below with reference to the accompanying drawings, and comprises a boiler 1, a coal-fired burner 2, a biomass burner 3 and a detection device 4.

A coal-fired burner 2 is provided in the boiler 1 for burning coal. A biomass burner 3 is provided in the boiler 1 for combusting biomass, and the biomass burner 3 is located above the coal-fired burner 2. The coal-fired burner 2 and the biomass burner 3 are spaced at a certain distance in the vertical direction, and when the biomass is combusted by coupling the coal-fired burner with the biomass, the staged combustion in the boiler is realized, and NO is realized_XReduction control of (3) reduction of NO_XAnd (5) discharging.

The detection device 4 is arranged at the tail part of the boiler and is used for detecting the smoke at the tail part of the boiler when only coal is combusted, only biomass is combusted and the coal and the biomass are combusted in a coupling wayOxygen content and carbon dioxide content. In other words, only the coal is burned in the boiler, and the detection device 4 can respectively measure the oxygen content VO in the flue gas at the tail of the boiler₂1 and carbon dioxide content VCO₂1; only biomass is burned in the boiler, and the detection device 4 can respectively measure the oxygen content VO in the flue gas at the tail of the boiler₂2 and carbon dioxide content VCO₂2; the fire coal and the biomass are coupled and combusted in the boiler, and the detection device 4 can respectively measure the oxygen content VO in the flue gas at the tail part of the boiler₂3 and carbon dioxide content VCO₂3。

VO thus detected by the detection device 4₂1 and VCO₂1、VO₂2 and VCO₂2 and VO₂3 and VCO₂3, the content VCO of the carbon dioxide based on the standard oxygen amount in the flue gas when only the coal is combusted in the boiler can be respectively obtained₂1s、VCO₂2s and VCO₂And 3s, and obtaining the heat share R of the biomass input into the boiler during the coupled combustion of the fire coal and the biomass according to the formula (1).

According to the system for detecting the biomass heat share in the combustion of the coal-fired coupled biomass, the detection device is arranged at the tail of the boiler, so that the oxygen content and the carbon dioxide content in the flue gas at the tail of the boiler can be detected when only the coal is combusted, only the biomass is combusted and the coal and the biomass are combusted in a coupled mode, the biomass heat proportion input into the boiler in the combustion of the coal-fired coupled biomass can be calculated conveniently by using the formula (1), the measurement and statistics of the biomass power generation amount of the coupled generator set are realized, the structure of the system is relatively simple, and the accuracy of the obtained biomass heat share is high.

In some embodiments, the detection device 4 comprises a first detection device 41 and a second detection device 42, and the first detection device 41 is used for detecting the oxygen content in the flue gas at the tail of the boiler. The second detection device 42 is used for detecting the carbon dioxide content in the flue gas at the tail of the boiler.

Further, the first detecting device 41 is used for detecting the oxygen volume concentration in the boiler tail flue gas in a dry basis state, and the second detecting device 42 is used for detecting the carbon dioxide volume concentration in the boiler tail flue gas in the dry basis state.

In some embodiments, the system for detecting biomass heat share in the coal-fired coupled biomass combustion further comprises a coal pulverizing device 5 and a first analysis and metering device 6.

The coal pulverizing device 5 is located outside the boiler 1 and connected to the coal-fired burner 2, and the coal pulverizing device 5 is used for crushing and pulverizing the coal and supplying the coal into the coal-fired burner 2. The raw coal is crushed and pulverized by the coal pulverizing device and then is sent to a coal-fired burner in the boiler, so that the combustion of the pulverized coal in the boiler is realized.

The first analyzing and metering device 6 is positioned outside the boiler 1, is connected with the coal pulverizing device 5 and the coal-fired burner 2, and is used for detecting the coal quality components, the low heat value and the mass flow of the coal-fired entering the boiler 1. Specifically, the first analyzing and metering device 6 is disposed between the coal pulverizing device 5 and the coal-fired burner 2, and is connected to both the coal pulverizing device 5 and the coal-fired burner 2.

Further, the system for detecting the biomass heat share in the combustion of the coal-fired coupled biomass further comprises a biomass pulverizing device 7 and a second analysis metering device 8.

The biomass pulverizing device 7 is located outside the boiler 1 and connected with the biomass burner 3, and is used for crushing and pulverizing biomass and supplying the biomass into the biomass burner 3. The biomass powder is crushed and pulverized by the biomass pulverizing device and then is sent to the biomass burner in the boiler, so that the combustion of the biomass powder in the boiler is realized.

The second analysis metering device 8 is located outside the boiler 1, is connected with the biomass pulverizing device 7 and the biomass burner 3, and is used for detecting biomass components, low-level heat value and mass flow entering the boiler 1. Specifically, the second analyzing and metering device 8 is arranged between the biomass pulverizing device 7 and the biomass burner 3, and is connected with both the biomass pulverizing device 7 and the biomass burner 3.

The inventor discovers through research that for a coal-fired and biomass-coupled power generation boiler, in order to accurately measure the biomass fuel input heat share entering the boiler, the biomass fuel input heat share is analyzed and counted by the first analysis and measurement device 6 and the second analysis and measurement device 8, the biomass fuel input heat share is influenced by the changeable characteristics of the biomass fuel, the accurate measurement is difficult to achieve, the engineering requirement cannot be met, and the basis requirements of supervision and online electricity price subsidy cannot be met.

Therefore, the inventor analyzes the characteristics of the biomass fuel, eliminates the influence factors of moisture, ash and low calorific value in the biomass fuel, has relatively fixed carbon-hydrogen ratio of a certain type of biomass, considers the biomass fuel with a specific component as a reference biomass, and changes the components of flue gas of the biomass deviating from the reference biomass in actual operation after the biomass is combusted, thereby judging the share of the biomass input heat in the total input heat of the boiler, and simplifying the detection process and the method.

In some embodiments, the system for detecting biomass heat share in coal-fired coupled biomass combustion further comprises an over-fire air nozzle 9, the over-fire air nozzle 9 being disposed within the boiler 1 and above the biomass burner 3. In this embodiment, hot air can be fed separately above the biomass burner 3 and the coal-fired burner 2 through the overfire air nozzle, so that the fuel entering the boiler is combusted through the secondary air, the coal and/or biomass fuel is further combusted at the later stage, and NO is reduced_XAnd (4) generating.

Therefore, when only coal is combusted in the boiler, raw coal is crushed and pulverized by the coal pulverizing device and then is fed into the coal-fired burner in the boiler, and secondary air provided by the over-fire air nozzle assists pulverized coal combustion to realize combustion of pulverized coal in the boiler. When only burning living beings in the boiler, carry out breakage, powder process with the raw coal through living beings powder process device, then send into the living beings fuel nozzle in the boiler, the secondary air that provides through the overfire air nozzle assists the burning of living beings powder, realizes the burning of living beings powder in the boiler. When the coal and the biomass are coupled and combusted in the boiler, the coal pulverizing device pulverizes and pulverizes raw coal, and then the raw coal is fed into a coal burner in the boiler; the biomass powder making device is used for crushing and making powder of raw coal, and then the raw coal is sent to a biomass burner in a boiler; the secondary air provided by the over-fire air nozzle respectively assists the combustion of the pulverized coal and the biomass powder, so that the mixed combustion of the pulverized coal and the biomass powder in the boiler is realized, and the steam is generated for power generation, thereby realizing the direct coupling power generation of the coal and the biomass in the boiler.

In some embodiments, the system for detecting the biomass heat share in the combustion of the biomass coupled with the coal further comprises an economizer 10 and an SCR denitration device 11, wherein the economizer 10 and the SCR denitration device 11 are both arranged in the boiler 1, and the detection device 4 is located between the economizer 10 and the SCR denitration device 11. Specifically, the economizer 10 is installed in a flue at the tail of the boiler, and is used for recovering waste heat of the discharged flue gas, saving energy and improving efficiency. The denitration device 11 can use ammonia or urea as a reducing agent, the reducing agent and Nitrogen Oxide (NO) in the flue gas under the action of a metal catalyst at a certain temperature_X) The reduction reaction is carried out to generate harmless nitrogen and water vapor, and the harmless nitrogen and the water vapor do not react with oxygen in the flue gas, so that the nitrogen oxide in the flue gas is removed.

In some embodiments, the system for detecting the biomass heat share in the coal-fired coupled biomass combustion further comprises an air preheater 12, and the air preheater 12 is arranged at the tail end of the boiler 1. In this embodiment, can be with the heat that carries in the exhaust flue gas in the boiler afterbody flue through the air preheater, in conducting the air before getting into the boiler through the fin, preheat the air to certain temperature to improve boiler heat exchange performance, reduce the heat energy consumption.

The method for detecting the biomass heat share in the combustion of the coal-fired coupled biomass according to the embodiment of the invention is described below with reference to the attached drawings 1 and 2.

The method for detecting biomass heat share in coal-fired coupled biomass combustion specifically adopts a system comprising a boiler 1, a coal-fired burner 2, a biomass burner 3, a first detection device 41, a second detection device 42, a coal pulverizing device 5, a first analyzing and metering device 6, a biomass pulverizing device 7, a second analyzing and metering device 8, an over-fire air nozzle 9, an economizer 10, an SCR denitration device 11 and an air preheater 12. In this system, the coal burner 2, the biomass burner 3, the first detection device 41, the second detection device 42, and the overfire air nozzle 9 are all provided in the boiler 1. The coal burner 2, the biomass burner 3 and the overfire air nozzle 9 are arranged in this order in the direction from the bottom to the top and spaced apart from each other. The economizer 10, the SCR denitration device 11 and the air preheater 12 are all arranged in a tail flue of the boiler 1, the economizer 10, the SCR denitration device 11 and the air preheater 12 are arranged at intervals along the discharge direction of flue gas, and the air preheater 12 is arranged at the tail end of the tail flue of the boiler 1.

The coal-fired pulverizing device 5, the first analyzing and metering device 6, the biomass pulverizing device 7 and the second analyzing and metering device 8 are arranged outside the boiler 1. A coal pulverizing apparatus 5 is connected to the coal-fired burner 2 to pulverize and pulverize the coal and supply it to the coal-fired burner 2. The first analysis metering device 6 is arranged between the coal pulverizing device 5 and the coal-fired burner 2 and is connected with both the coal pulverizing device 5 and the coal-fired burner 2. A biomass pulverizing device 7 and a biomass burner 3 to crush and pulverize biomass and supply the biomass into the biomass burner 3. The second analysis metering device 8 is arranged between the biomass powder making device 7 and the biomass burner 3 and is connected with both the biomass powder making device 7 and the biomass burner 3.

The method for detecting the biomass heat share in the combustion of the fire coal coupled biomass comprises the following steps:

when only the coal is burned in the boiler 1, the oxygen content VO in the flue gas on a dry basis is measured at the tail of the boiler 1 by means of the first detection device 41₂1, measuring the content VCO of the carbon dioxide in the flue gas under the dry basis through a second detection device 42₂1；

When only biomass is burned in the boiler 1, the oxygen content VO in the flue gas on a dry basis is measured at the tail of the boiler 1 by means of the first detection device 41₂2, measuring the content VCO of the carbon dioxide in the flue gas under the dry basis through a second detection device 42₂2；

When the fire coal and the biomass are combusted in a coupled manner in the boiler 1, on the one hand, the lower calorific value L HV1 and the mass flow m1 of the fire coal are detected by the first analytical metering device 6, and the lower calorific value L HV2b and the mass flow m2 of the reference biomass are detected by the second analytical metering device 8, and on the other hand, the oxygen content VO in the flue gas on a dry basis is measured at the tail of the boiler 1 by the first detection device 41₂3, measuring the content VCO of the carbon dioxide in the flue gas under the dry basis through a second detection device 42₂3；

Considering the difference of the smoke components when the boiler 1 burns under different excess air coefficients, the three carbon dioxide contents are firstly converted into the concentrations under the 6% oxygen standard, which are respectively:

the heat share R of biomass input into a boiler during coupled combustion of coal and biomass is obtained according to the following formula (1):

further, the method for detecting the biomass heat share in the combustion of the coal-fired coupled biomass of the embodiment of the invention further comprises the following steps:

the heat share R of biomass input into a boiler during the coupled combustion of the fire coal and the biomass is obtained according to the following formula₁：

Comparing R and R₁It is verified whether the error of R obtained by equation (1) meets operational and metering requirements.

Further, considering that the lower calorific value of the biomass charged into the furnace varies with the moisture and ash content thereof, the lower calorific value of the biomass charged into the furnace varies accordingly, wherein the moisture and ash content of the reference biomass are Mar2b and Aar2b, the moisture and ash content of the biomass charged into the furnace are Mar2 and Aar2, respectively, and the lower calorific value of the biomass charged into the furnace is L HV2, the lower calorific value of the biomass charged into the furnace is determined to be

Obtaining the heat share R of the biomass input into the boiler during the coupled combustion of the coal and the biomass according to the following formula (5) and substituting the formula (6) into the formula (5)₀：

Comparing R and R₀It is verified whether the error of R obtained by equation (1) meets operational and metering requirements.

Because the moisture and the ash in the biomass do not generate heat during combustion, the heat generated by the combustion of the biomass mainly comes from carbon and hydrogen elements, once the moisture and the ash in the biomass entering the boiler deviate from the reference biomass, the lower calorific value of the biomass can be corrected through a formula (6), meanwhile, when the biomass is combusted in the boiler, the moisture and the ash deviating from the components of the reference biomass do not influence the components of dry-based flue gas, and CO in the dry-based flue gas₂The volume concentration depends only on the type of biomass, i.e. the carbon to hydrogen ratio.

The rationality of the present application is analyzed below with reference to some specific coal and biomass coupled combustion cases.

For a 600MW thermal power generating unit, the fire coal is brown coal, the biomass is corn stalks, the main coal quality data of the fire coal is Care-38.73%, Har-2.57%, Oar-12.36%, Nar-0.79%, Sar-0.28%, Aar-14.38%, Mar-30.89%, L HV-13090 kJ/kg, the biomass fuel components are Care-34.75%, Har-4.07%, Oar-32.02%, Nar-0.42%, Sar-0.03%, Aar-3.7%, Mar-25.01%, L HV-11860 kJ/kg, and the biomass with the components is defined as reference biomass.

When only the fire coal is combusted in the boiler, the detection device 4 detects and obtains O in the flue gas₂Volume concentration and CO₂Volume concentration and conversion to CO according to formula (2)₂On a dry basis, 6% O₂The volume concentration under the conditions was 13.99%.

When in a boilerWhen only biomass is combusted, O in the flue gas is detected by the detection device 4₂Volume concentration and CO₂The volume concentration is converted into CO according to the formula (3)₂On a dry basis, 6% O₂The volume concentration under the conditions was 14.85%.

When the boiler is used for coupling combustion of the fire coal and the biomass, namely, the fire coal is coupled with the biomass for power generation, the coal combustion amount is 218.2t/h through the first analysis metering device 6; the biomass of 250t/h is obtained by the second analysis and metering device 8, and the calculated share R of the input heat of the biomass fuel in the total input heat of the boiler₁50.93%;

detecting by the detection device 4 to obtain O in the flue gas₂Volume concentration and CO₂The volume concentration is converted into CO according to the formula (4)₂On a dry basis, 6% O₂The volume concentration under the condition is 14.41%, and the biomass fuel input heat quantity share R calculated by the method of the invention is 48.98%.

It can be seen that the biomass fuel input heat share R obtained by the method of the present invention and the biomass fuel input heat share R obtained by the calculation of the coal burning quantity and the biomass₁Compared with the prior art, the error of the input heat share R of the biomass fuel obtained by the method is about 1.9 percent, and the operation and metering requirements are met.

When the boiler is used for coupling combustion of the fire coal and the biomass, namely, during power generation operation of coupling the fire coal and the biomass, the coal combustion amount is 304.1t/h through the first analyzing and metering device 6, and the input biomass is 150t/h through the second analyzing and metering device 8, so that the calculated share R of the input heat of the biomass fuel in the total input heat of the boiler₁30.89%;

detecting by the detection device 4 to obtain O in the flue gas₂Volume concentration and CO₂The volume concentration is converted into CO according to the formula (4)₂On a dry basis, 6% O₂The volume concentration under the condition is 14.24%, and the biomass fuel input heat share R calculated by the method of the invention is 29.13%.

It can be seen that the biomass fuel input heat share R obtained by the method of the present invention is in communication withThe biomass fuel input heat share R obtained by calculating the overfire coal amount and the biomass₁Compared with the prior art, the error of the input heat share R of the biomass fuel obtained by the method is about 1.8 percent, and the operation and metering requirements are met.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.