CN106093336A - A kind of method of online determination boiler combustion coal elements composition - Google Patents

Abstract

The invention discloses a kind of method of online determination boiler combustion coal elements composition, include oxygen amount, sulfur dioxide, carbon dioxide and flue gas volume flow based on the concentration analysis data of air preheater exiting flue gas composition, in conjunction with combustion in situ ature of coal coal quantity flow, online ash content and online moisture data, by specific computational methods and step, may determine that each elemental composition composition of properly functioning middle burning ature of coal, solve the problem how properly functioning middle boiler of power plant burning ature of coal carries out accurate measurements；The monitoring method that the present invention provides is simple and easy to do, is that power plant's accurate measurements boiler combustion ature of coal provides a kind of possible selection.

Description

A kind of method of online determination boiler combustion coal elements composition

Technical field

Patent of the present invention relates to a kind of method of online determination boiler combustion coal elements composition.

Background technology

The monitoring of boiler combustion ature of coal, can provide foundation for the calorific value predicting power plant combustion ature of coal.With sending out of technology Exhibition, the ash content of ature of coal and moisture had on-line instrument to be monitored, but the element of the ature of coal that how to realize burning divides online Analysis, is still the difficult problem facing.

Therefore in the urgent need to a kind of based on field measurement data, the side of on-line analysis can be carried out to boiler combustion ature of coal Method solves current problem.

Patent of invention content

Patent of the present invention to solve the technical problem that the side being to provide a kind of online determination boiler combustion coal elements composition Method.

The present invention comprises the following steps that

(14), the smoke components of chimney is monitored, gathers the flue gas data of air preheater outlet；Flue gas data include CO₂、O₂、SO₂Content and flue gas volume flow, the measuring basis of flue gas data is butt, uses CO successively_2k、O_2k、SO_2kWith And V_kRepresent, CO_2k、O_2k、SO_2kUnit be %, V_kUnit be m³/h；

(15), the V that will gather in step (14)_kSubstitute into formula (9), the coal-fired corresponding dry flue gas mole of unit of account quality Number Mo_DFG, unit is mol/kg；

${\mathrm{Mo}}_{DFG}=\frac{V_k\×(p_a+p_k)}{F_f\×8314.5\×(t_k+273.15)}---\left(9\right),$

F_fFor unit coal-burning mass flow, unit is kg/h；p_a, p_kIt is respectively environment atmospheric pressure, air preheater exiting flue gas Gauge pressure, unit is Pa；t_kFor air preheater exit gas temperature, unit for DEG C.

(16), the CO that will gather in step (14)_2kCalculate the Mo of gained with formula (9)_DFGSubstitute into formula (10), calculate single The degree MpCb of after-flame carbon during position quality is coal-fired, unit is %,

MpCb=Mo_DFG×CO_2k× 12.011 (10),

The molal weight that 12.011 is carbon, unit g/mol；

(17), the SO that will gather in step (14)_2kCalculate the Mo of gained with formula (9)_DFGSubstitute into formula (11), calculate single The degree MpSF of sulphur during position quality is coal-fired, unit is %,

MpSF=Mo_DFG×SO_2k× 32.065 (11),

The molal weight that 32.065 is sulphur, unit g/mol；

(18), H degree in fire coal is calculated:

First, the degree MpUBC of the uncompleted burned carbon during unit of account quality is coal-fired, unit is %,

$MpUBC=MpASF\×(0.1\×\frac{{\mathrm{MpCR}}_{lz}}{100-{\mathrm{MpCR}}_{lz}}+0.9\×\frac{{\mathrm{MpCR}}_{fh}}{100-{\mathrm{MpCR}}_{fh}})---\left(12\right),$

MpASF is the degree of ash content in unit quality fire coal, and unit is %, and MpASF data are grey online by fire coal Point measuring instrument is directly measured and is obtained；

MpCR_lzFor the mass percent of the carbon in dry bottom furnace slag, unit is %, MpCR_lzData are online by scene Measure or take fixed value；

MpCR_fhFor the mass percent of the carbon in dry ash extraction converter fly ash, unit is %, MpCR_fhData are online by scene Measure or take fixed value；

Secondly, formula (12) is calculated the MpUBC of gained and formula (10) calculates MpCb substitution formula (13) of gained, meter Calculating the C degree MpCF in fire coal, unit is %,

MpCF=MpCb+MpUBC (13),

Finally, the MpCF that formula (13) calculates gained substitutes into the percentage of the hydrogen in formula (15) unit of account quality fire coal Ratio content MpH2F, unit is %；

$\frac{MpH2F\×100}{100-MpWF-MpASF}=a+b\×\frac{MpCF\×100}{100-MpWF-MpASF}---\left(14\right),$

$MpH2F=\[a+b\×\frac{MpCF\×100}{100-MpWF-MpASF}\]\×\frac{100-MpWF-MpASF}{100}---\left(15\right)$

MpWF, MpASF are respectively the degree of the moisture in fire coal and ash content, and by on-the-spot online water analysis Instrument and ash content on-line instrument directly obtain；

A, b are the constant of fitting linear function, are obtained by laboratory's sample analysis data matching of each power plant combustion ature of coal；

(19), the nitrogen degree MpN2F in fire coal, unit is %, is taken as according to power plant coal quality analysis data gained Constant；

(20), formula (13) is calculated the MpCF of gained, formula (11) calculates the MpSF of gained, formula (15) calculates gained MpH2F, the MpN2F that step (19) obtains, MpWF, MpASF in step (18) substitute into formula (16), calculate coal-fired in oxygen Degree MpO2F, unit is %,

MpO2F=100-MpCF-MpSF-MpH2F-MpN2F-MpWF-MpASF (16).

Further, in described step (14), measuring point is set by air preheater outlet and directly measures CO_2k、O_2k、SO_2kWith/ Or V_k。

Further, before described step (14), further comprising the steps of:

(1), power plant's online emission monitoring system CEMS being arranged by chimney import, records chimney import O₂Content with And flue gas volume flow, the measuring basis of flue gas data is butt, uses O respectively_2s、V_stRepresent, O_2s, unit be %, V_stList Position is m³/h；Measuring point is set by air preheater outlet and directly measures O_2k, unit is %,

(2), the O that step (1) is recorded_2sSubstitute into formula (1) and calculate the flue gas excess air coefficient α of chimney entrance location_s,

${\mathrm{\α}}_s=\frac{21}{21-O_{2s}}---\left(1\right);$

(3), the O that step (1) is recorded_2kSubstitute into formula (2) and calculate the flue gas excess air coefficient of air preheater exit position α_k,

${\mathrm{\α}}_k=\frac{21}{21-O_{2k}}---\left(2\right);$

(4), formula (1) is calculated the α of gained_sCalculate the α of gained with formula (2)_kSubstitute into formula (3), calculate air preheater and go out Mouthful to middle air leak rate of air curtain A of chimney import_L, unit is %,

$A_L=\frac{{\mathrm{\α}}_s-{\mathrm{\α}}_k}{{\mathrm{\α}}_k}\×90---\left(3\right);$

(5), according to air preheater exit gas temperature, air preheater exiting flue gas density p is calculated_k, kg/m³；

(6), step (5) is calculated the ρ of gained_kSubstitute in formula (4), calculate the dry flue gas mass flow of air preheater outlet G_k, unit is kg/h,

G_k=V_k’×ρ_k(4),

V_k’For assuming air preheater outlet dry flue gas volume flow, unit is m³/h；

(7), formula (3) will calculate the A of gained_LAnd formula (4) calculates the G of gained_kSubstitute in formula (5), calculate Chimney import flue gas mass flow G_s, unit is kg/h,

$G_s=G_k\×(1+\frac{A_L}{100})---\left(5\right);$

(8), according to chimney input gas temperature, chimney import dry flue gas density p is calculated_s, kg/m³；

(9), formula (5) is calculated the G of gained_sAnd step (8) calculates the ρ of gained_sSubstitute into formula (6), calculate chimney Import dry flue gas volume flow Vs, unit is m³/ h,

$V_s=\frac{G_s}{{\mathrm{\ρ}}_s}---\left(6\right);$

(10), the V that the Vs of formula (6) gained is recorded with step (1)_stSubstitute into formula (7), ratio calculated absolute value coefficient K,

K=abs [(Vs-Vst)/Vst] (7)；

(11) whether K, is compared less than 0.001:

If K >=0.001, reset V_k’Assumed value, repeat step (6)-(10), until K ＜ 0.001；

If K ＜ 0.001, then V_k’Assumed value be given to V_k, obtain air preheater exiting flue gas volume flow V_k, enter step (14)。

Further, after described step (11) and before described step (14), further comprising the steps of:

(12), power plant's online emission monitoring system CEMS is set by chimney import, records chimney import CO₂Content, surveys Amount benchmark is butt, uses CO_2sRepresent, CO_2sUnit be %；

(13), the CO that step (12) is recorded_2s, the V that obtains of step (11)_kAnd the V that step (1) records_stSubstitute into formula (8), in, air preheater exiting flue gas CO is calculated₂Content,

${\mathrm{CO}}_{2k}={\mathrm{CO}}_{2s}\×\frac{V_{st}}{V_k}\×\frac{p_a+p_s}{p_a+p_k}\×\frac{t_k+273.15}{t_s+273.15}---\left(8\right);$

p_sFor chimney import flue gas gauge pressure, unit is Pa,

t_sFor chimney input gas temperature, unit for DEG C,

p_a, p_kBeing respectively environment atmospheric pressure, air preheater exiting flue gas gauge pressure, unit is Pa；

t_kFor air preheater exit gas temperature, unit for DEG C；

Enter step (14).

Use and have the beneficial effects that produced by technique scheme:

Patent of the present invention includes oxygen amount, sulfur dioxide, dioxy based on the concentration analysis data of air preheater exiting flue gas composition Change carbon and flue gas volume flow, in conjunction with combustion in situ ature of coal coal quantity flow, online ash content and online moisture data, pass through Specific computational methods and step, it may be determined that each elemental composition composition of properly functioning middle burning ature of coal, solve normal fortune The problem that in row, how boiler of power plant burning ature of coal carries out accurate measurements.Both the needs that economy of power plant is analyzed had been met, it is possible to For realizing that electrical network provides foundation and guidance to the energy-saving distribution of Power Plant from now on.

Detailed description of the invention

Below in conjunction with detailed description of the invention, patent of the present invention is described in further detail.

The present invention comprises the following steps that

(1), power plant's online emission monitoring system CEMS being arranged by chimney import, records chimney import O₂Content with And flue gas volume flow, the measuring basis of flue gas data is butt, uses O respectively_2s、V_stRepresent, O_2s, unit be %, V_stList Position is m³/h；Measuring point is set by air preheater outlet and directly measures O_2k, unit is %,

(2), the O that step (1) is recorded_2sSubstitute into formula (1) and calculate the flue gas excess air coefficient α of chimney entrance location_s,

${\mathrm{\α}}_s=\frac{21}{21-O_{2s}}---\left(1\right);$

(3), the O that step (1) is recorded_2kSubstitute into formula (2) and calculate the flue gas excess air coefficient of air preheater exit position α_k,

${\mathrm{\α}}_k=\frac{21}{21-O_{2k}}---\left(2\right);$

(4), formula (1) is calculated the α of gained_sCalculate the α of gained with formula (2)_kSubstitute into formula (3), calculate air preheater and go out Mouthful to middle air leak rate of air curtain A of chimney import_L, unit is %,

$A_L=\frac{{\mathrm{\α}}_s-{\mathrm{\α}}_k}{{\mathrm{\α}}_k}\×90---\left(3\right);$

(5), according to air preheater exit gas temperature, air preheater exiting flue gas density p is calculated_k, kg/m³；

(6), step (5) is calculated the ρ of gained_kSubstitute in formula (4), calculate the dry flue gas mass flow of air preheater outlet G_k, unit is kg/h,

G_k=V_k’×ρ_k(4),

V_k’For assuming air preheater outlet dry flue gas volume flow, unit is m³/h；

(7), formula (3) will calculate the A of gained_LAnd formula (4) calculates the G of gained_kSubstitute in formula (5), calculate Chimney import flue gas mass flow G_s, unit is kg/h,

$G_s=G_k\×(1+\frac{A_L}{100})---\left(5\right);$

(8), according to chimney input gas temperature, chimney import dry flue gas density p is calculated_s, kg/m³；

(9), formula (5) is calculated the G of gained_sAnd step (8) calculates the ρ of gained_sSubstitute into formula (6), calculate chimney Import dry flue gas volume flow Vs, unit is m³/ h,

$V_s=\frac{G_s}{{\mathrm{\ρ}}_s}---\left(6\right);$

(10), the V that the Vs of formula (6) gained is recorded with step (1)_stSubstitute into formula (7), ratio calculated absolute value coefficient K,

K=abs [(Vs-Vst)/Vst] (7)；

(11) whether K, is compared less than 0.001:

If K >=0.001, reset V_k’Assumed value, repeat step (6)-(10), until K ＜ 0.001；

If K ＜ 0.001, then V_k’Assumed value be given to V_k, obtain air preheater exiting flue gas volume flow V_k, enter step (14)。

In addition, for content CO_2sCan be acquired according to step (12), (13)；

(12), power plant's online emission monitoring system CEMS is set by chimney import, records chimney import CO₂Content, surveys Amount benchmark is butt, uses CO_2sRepresent, CO_2sUnit be %；

(13), the CO that step (12) is recorded_2s, the V that obtains of step (11)_kAnd the V that step (1) records_stSubstitute into formula (8), in, air preheater exiting flue gas CO is calculated₂Content,

${\mathrm{CO}}_{2k}={\mathrm{CO}}_{2s}\×\frac{V_{st}}{V_k}\×\frac{p_a+p_s}{p_a+p_k}\×\frac{t_k+273.15}{t_s+273.15}---\left(8\right);$

p_sFor chimney import flue gas gauge pressure, unit is Pa,

t_sFor chimney input gas temperature, unit for DEG C,

p_a, p_kBeing respectively environment atmospheric pressure, air preheater exiting flue gas gauge pressure, unit is Pa；

t_kFor air preheater exit gas temperature, unit for DEG C；

Enter step (14).

As the improvement of step (1)-(13), in described step (14), measuring point is set by air preheater outlet and directly surveys Amount CO_2k、O_2k、SO_2kAnd/or V_k。

(14), the smoke components of chimney is monitored, gathers the flue gas data of air preheater outlet；Flue gas data include CO₂、O₂、SO₂Content and flue gas volume flow, the measuring basis of flue gas data is butt, uses CO successively_2k、O_2k、SO_2kWith And V_kRepresent, CO_2k、O_2k、SO_2kUnit be %, V_kUnit be m³/h；

(15), the V that will gather in step (14)_kSubstitute into formula (9), the coal-fired corresponding dry flue gas mole of unit of account quality Number Mo_DFG, unit is mol/kg；

${\mathrm{Mo}}_{DFG}=\frac{V_k\×(p_a+p_k)}{F_f\×8314.5\×(t_k+273.15)}---\left(9\right),$

F_fFor unit coal-burning mass flow, unit is kg/h；p_a, p_kIt is respectively environment atmospheric pressure, air preheater exiting flue gas Gauge pressure, unit is Pa；t_kFor air preheater exit gas temperature, unit for DEG C.

(16), the CO that will gather in step (14)_2kCalculate the Mo of gained with formula (9)_DFGSubstitute into formula (10), calculate single The degree MpCb of after-flame carbon during position quality is coal-fired, unit is %,

MpCb=Mo_DFG×CO_2k× 12.011 (10),

12.011 for the molal weight of carbon, unit g/mol；

(17), the SO that will gather in step (14)_2kCalculate the Mo of gained with formula (9)_DFGSubstitute into formula (11), calculate single The degree MpSF of sulphur during position quality is coal-fired, unit is %,

MpSF=Mo_DFG×SO_2k× 32.065 (11),

The molal weight that 32.065 is sulphur, unit g/mol；

(18), H degree in fire coal is calculated:

First, the degree MpUBC of the uncompleted burned carbon during unit of account quality is coal-fired, unit is %,

$MpUBC=MpASF\×(0.1\×\frac{{\mathrm{MpCR}}_{lz}}{100-{\mathrm{MpCR}}_{lz}}+0.9\×\frac{{\mathrm{MpCR}}_{fh}}{100-{\mathrm{MpCR}}_{fh}})---\left(12\right),$

MpASF is the degree of ash content in unit quality fire coal, and unit is %, and MpASF data are grey online by fire coal Point measuring instrument is directly measured and is obtained；

MpCR_lzFor the mass percent of the carbon in dry bottom furnace slag, unit is %, MpCR_lzData are online by scene Measure or take fixed value；

MpCR_fhFor the mass percent of the carbon in dry ash extraction converter fly ash, unit is %, MpCR_fhData are online by scene Measure or take fixed value；

Secondly, formula (12) is calculated the MpUBC of gained and formula (10) calculates MpCb substitution formula (13) of gained, meter Calculating the C degree MpCF in fire coal, unit is %,

MpCF=MpCb+MpUBC (13),

Finally, the MpCF that formula (13) calculates gained substitutes into the percentage of the hydrogen in formula (15) unit of account quality fire coal Ratio content MpH2F, unit is %；

$\frac{MpH2F\×100}{100-MpWF-MpASF}=a+b\×\frac{MpCF\×100}{100-MpWF-MpASF}---\left(14\right),$

$MpH2F=\[a+b\×\frac{MpCF\×100}{100-MpWF-MpASF}\]\×\frac{100-MpWF-MpASF}{100}---\left(15\right)$

MpWF, MpASF are respectively the degree of the moisture in fire coal and ash content, and by on-the-spot online water analysis Instrument and ash content on-line instrument directly obtain；

A, b are the constant of fitting linear function, are obtained by laboratory's sample analysis data matching of each power plant combustion ature of coal；

(19), the nitrogen degree MpN2F in fire coal, unit is %, is taken as according to power plant coal quality analysis data gained Constant；

(20), formula (13) is calculated the MpCF of gained, formula (11) calculates the MpSF of gained, formula (15) calculates gained MpH2F, the MpN2F that step (19) obtains, MpWF, MpASF in step (18) substitute into formula (16), calculate coal-fired in oxygen Degree MpO2F, unit is %,

MpO2F=100-MpCF-MpSF-MpH2F-MpN2F-MpWF-MpASF (16).

When wherein step (5) and step (8) calculating dry flue gas density, according to standard GB/T 10184-1988 " boiler Performance test code " in the computational methods that provide calculate air preheater exiting flue gas density according to the flue-gas temperature of relevant position ρ_k, chimney import smoke density ρ_s。

Specific embodiment:

The boiler of certain 600MW grade, the parameter that under certain steady running condition, in-site measurement obtains is as follows:

In above-mentioned data:

A, b are the constant of fitting linear function, are obtained by laboratory's sample analysis data matching of each power plant combustion ature of coal；

Mass percent MpCR of the carbon in slag_lz, mass percent MpCR of the carbon in flying dust_fhBy the online instrument in scene Table measurement obtains.

Coal-fired moisture as received coal content MpWF, coal-fired As-received content of ashes MpASF is by on-the-spot online moisture analyser Device and ash content on-line instrument directly obtain.

Chimney import O2 content (butt) O_2s, chimney import CO2 content (butt) CO_2s, chimney import flue gas gauge pressure p_s, cigarette Chimney input gas temperature t_s, chimney import dry flue gas volume V_st, power plant's online emission monitoring system of being arranged by chimney import CEMS obtains related data.

Unit coal-burning mass flow F_f, environment atmospheric pressure p_a, obtained by data unit operation；

Air preheater exports O2 content (butt) O_2k, air preheater exports SO2 content (butt) SO_2k, air preheater exiting flue gas temperature Degree t_k, air preheater exiting flue gas gauge pressure p_k, obtained by data unit operation；

Enforcement step:

(1). measure O2 content (butt) O according to chimney import_2s, calculate flue gas excess air coefficient α according to formula (1)_s =1.4305；

(2). export measurement O2 content (butt) O according to air preheater_2k, calculate flue gas excess air coefficient according to formula (2) α_k=1.3609；

(3). calculate, according to formula (3), middle air leak rate of air curtain A that air preheater is exported to chimney import_L=4.6042%；

(4). according to air preheater exit gas temperature t_k, according to standard GB/T 10184-1988, " boiler performance test is advised Journey " the middle computational methods providing, calculate air preheater exiting flue gas density p_k=0.8982kg/m³；

(5). assume air preheater outlet dry flue gas volume flow V_k’For 2669139m³/ h, exports according to formula (4) air preheater Dry flue gas mass flow G_k=2397401kg/h；

(6). calculate chimney import flue gas mass flow G according to formula (5)_s=2507783kg/h；

(7). according to chimney input gas temperature t_s, according to standard GB/T 10184-1988 " boiler performance test code " The computational methods of middle offer, calculate chimney import dry flue gas density p_s=1.0011kg/m³；

(8). calculate chimney import dry flue gas volume flow Vs=2504934kg/m according to formula (6)³；

(9). according to formula (7) ratio calculated absolute value COEFFICIENT K=0 < 0.001, therefore V_k=V_k’=2669139m³/h；

(10). calculate air preheater exiting flue gas CO according to formula (8)₂Content CO_2k=13.4307%；

(11). according to the coal-fired corresponding dry flue gas molal quantity Mo of formula (9) unit of account quality_DFG=0.3924；

(12). according to the degree MpCb=63.306% of formula (10) unit of account quality after-flame carbon in coal-fired；

(13). according to the degree MpSF=2.925% of formula (11) unit of account quality sulphur in coal-fired；

(14). according to the degree MpUBC=of the uncompleted burned carbon in formula (12) unit of account quality fire coal 0.377%；

(15). according to the degree MpCF=63.68% of the carbon in formula (13) unit of account quality fire coal；

(16). the degree MpH2F=4.315% of hydrogen content of coal is fired according to formula (15) unit of account quality；

(17). according to power plant coal quality analysis data, the nitrogen degree MpN2F in fire coal is taken as constant, MpN2F= 1.24%；

(18). fire oxygen content of coal degree MpO2F=7.32% according to formula (16) unit of account quality.

Claims (4)

1. the method for an online determination boiler combustion coal elements composition, it is characterised in that: comprise the following steps that

(14), the smoke components of chimney is monitored, gathers the flue gas data of air preheater outlet；Flue gas data include CO₂、O₂、 SO₂Content and flue gas volume flow, the measuring basis of flue gas data is butt, uses CO successively_2k、O_2k、SO_2kAnd V_kTable Show, CO_2k、O_2k、SO_2kUnit be %, V_kUnit be m³/h；

(15), the V that will gather in step (14)_kSubstitute into formula (9), the coal-fired corresponding dry flue gas molal quantity of unit of account quality Mo_DFG, unit is mol/kg；

${\mathrm{Mo}}_{DFG}=\frac{V_k\&times;(p_a+p_k)}{F_f\&times;8314.5\&times;(t_k+273.15)}---\left(9\right),$

F_fFor unit coal-burning mass flow, unit is kg/h；p_a, p_kIt is respectively environment atmospheric pressure, air preheater exiting flue gas table Pressure, unit is Pa；t_kFor air preheater exit gas temperature, unit for DEG C.

(16), the CO that will gather in step (14)_2kCalculate the Mo of gained with formula (9)_DFGSubstitute into formula (10), unit of account matter The degree MpCb of after-flame carbon during amount is coal-fired, unit is %,

MpCb=Mo_DFG×CO_2k× 12.011 (10),

The molal weight that 12.011 is carbon, unit g/mol；

(17), the SO that will gather in step (14)_2kCalculate the Mo of gained with formula (9)_DFGSubstitute into formula (11), unit of account matter The degree MpSF of sulphur during amount is coal-fired, unit is %,

MpSF=Mo_DFG×SO_2k× 32.065 (11),

The molal weight that 32.065 is sulphur, unit g/mol；

(18), H degree in fire coal is calculated:

First, the degree MpUBC of the uncompleted burned carbon during unit of account quality is coal-fired, unit is %,

$MpUBC=MpASF\&times;(0.1\&times;\frac{{\mathrm{MpCR}}_{lz}}{100-{\mathrm{MpCR}}_{lz}}+0.9\&times;\frac{{\mathrm{MpCR}}_{fh}}{100-{\mathrm{MpCR}}_{fh}})---\left(12\right),$

MpASF is the degree of ash content in unit quality fire coal, and unit is %, and MpASF data are surveyed by the online ash content of fire coal Measuring appratus is directly measured and is obtained；

MpCR_lzFor the mass percent of the carbon in dry bottom furnace slag, unit is %, MpCR_lzData are by on-site on-line measurement Or take fixed value；

MpCR_fhFor the mass percent of the carbon in dry ash extraction converter fly ash, unit is %, MpCR_fhData are by on-site on-line measurement Or take fixed value；

Secondly, formula (12) is calculated the MpUBC of gained and formula (10) calculates MpCb substitution formula (13) of gained, calculate combustion C degree MpCF in coal, unit is %,

MpCF=MpCb+MpUBC (13),

Finally, the percentage that formula (13) calculates the hydrogen in MpCF substitution formula (15) the unit of account quality fire coal of gained contains Amount MpH2F, unit is %；

$\frac{MpH2F\&times;100}{100-MpWF-MpASF}=a+b\&times;\frac{MpCF\&times;100}{100-MpWF-MpASF}---\left(14\right),$

$MpH2F=\&lsqb;a+b\&times;\frac{MpCF\&times;100}{100-MpWF-MpASF}\&rsqb;\&times;\frac{100-MpWF-MpASF}{100}---\left(15\right)$

MpWF, MpASF are respectively the degree of the moisture in fire coal and ash content, and by on-the-spot online Kinds of Moisture Monitors And ash content on-line instrument directly obtains；

A, b are the constant of fitting linear function, are obtained by laboratory's sample analysis data matching of each power plant combustion ature of coal；

(19), the nitrogen degree MpN2F in fire coal, unit is %, is taken as constant according to power plant coal quality analysis data gained；

(20), formula (13) is calculated the MpCF of gained, formula (11) calculates the MpSF of gained, formula (15) calculates gained MpH2F, the MpN2F that step (19) obtains, MpWF, the MpASF in step (18) substitutes into formula (16), calculates the oxygen hundred in fire coal Proportion by subtraction content MpO2F, unit is %,

MpO2F=100-MpCF-MpSF-MpH2F-MpN2F-MpWF-MpASF (16).

2. the method for a kind of online determination boiler combustion coal elements composition according to claim 1, it is characterised in that: In described step (14), measuring point is set by air preheater outlet and directly measures CO_2k、O_2k、SO_2kAnd/or V_k。

3. the method for a kind of online determination boiler combustion coal elements composition according to claim 1, it is characterised in that: Before described step (14), further comprising the steps of:

(1), power plant's online emission monitoring system CEMS being arranged by chimney import, records chimney import O₂Content and cigarette Air space flow, the measuring basis of flue gas data is butt, uses O respectively_2s、V_stRepresent, O_2s, unit be %, V_stUnit be m³/h；Measuring point is set by air preheater outlet and directly measures O_2k, unit is %,

(2), the O that step (1) is recorded_2sSubstitute into formula (1) and calculate the flue gas excess air coefficient α of chimney entrance location_s,

${\mathrm{\&alpha;}}_s=\frac{21}{21-O_{2s}}---\left(1\right);$

(3), the O that step (1) is recorded_2kSubstitute into formula (2) and calculate the flue gas excess air coefficient α of air preheater exit position_k,

${\mathrm{\&alpha;}}_k=\frac{21}{21-O_{2k}}---\left(2\right);$

(4), formula (1) is calculated the α of gained_sCalculate the α of gained with formula (2)_kSubstitute into formula (3), calculate air preheater and be exported to Middle air leak rate of air curtain A of chimney import_L, unit is %,

$A_L=\frac{{\mathrm{\&alpha;}}_s-{\mathrm{\&alpha;}}_k}{{\mathrm{\&alpha;}}_k}\&times;90---\left(3\right);$

(5), according to air preheater exit gas temperature, air preheater exiting flue gas density p is calculated_k, kg/m³；

(6), step (5) is calculated the ρ of gained_kSubstitute in formula (4), calculate dry flue gas mass flow G of air preheater outlet_k, single Position is kg/h,

G_k=V_k’×ρ_k(4),

V_k' for assuming air preheater outlet dry flue gas volume flow, unit is m³/h；

(7), formula (3) will calculate the A of gained_LAnd formula (4) calculates the G of gained_kSubstitute in formula (5), calculate chimney Import flue gas mass flow G_s, unit is kg/h,

$G_s=G_k\&times;(1+\frac{A_L}{100})---\left(5\right);$

(8), according to chimney input gas temperature, chimney import dry flue gas density p is calculated_s, kg/m³；

(9), formula (5) is calculated the G of gained_sAnd step (8) calculates the ρ of gained_sSubstitute into formula (6), calculate chimney import Dry flue gas volume flow Vs, unit is m³/ h,

$V_s=\frac{G_s}{{\mathrm{\&rho;}}_s}---\left(6\right);$

(10), the V that the Vs of formula (6) gained is recorded with step (1)_stSubstitution formula (7), ratio calculated absolute value COEFFICIENT K,

K=abs [(Vs-Vst)/Vst] (7)；

(11) whether K, is compared less than 0.001:

If K >=0.001, reset V_k, assumed value, repeat step (6)-(10), until K ＜ 0.001；

If K ＜ 0.001, then by V_k, assumed value be given to V_k, obtain air preheater exiting flue gas volume flow V_k, enter step (14)。

4. the method for a kind of online determination boiler combustion coal elements composition according to claim 3, it is characterised in that: After described step (11) and before described step (14), further comprising the steps of:

(12), power plant's online emission monitoring system CEMS is set by chimney import, records chimney import CO₂Content, measuring basis For butt, use CO_2sRepresent, CO_2sUnit be %；

(13), the CO that step (12) is recorded_2s、The V that step (11) obtains_kAnd the V that step (1) records_stSubstitute into formula (8) In, calculate air preheater exiting flue gas CO₂Content,

${\mathrm{CO}}_{2k}={\mathrm{CO}}_{2s}\&times;\frac{V_{st}}{V_k}\&times;\frac{p_a+p_s}{p_a+p_k}\&times;\frac{t_k+273.15}{t_s+273.15}---\left(8\right);$

p_sFor chimney import flue gas gauge pressure, unit is Pa,

t_sFor chimney input gas temperature, unit for DEG C,

p_a, p_kBeing respectively environment atmospheric pressure, air preheater exiting flue gas gauge pressure, unit is Pa；

t_kFor air preheater exit gas temperature, unit for DEG C；

Enter step (14).