CN104459542A - Heat rate measurement method for reheating regeneration combined cycle unit - Google Patents

Abstract

The invention discloses a heat rate measurement method for a reheating regeneration combined cycle unit. A turbine of the cycle unit is composed of a high pressure cylinder, an intermediate pressure cylinder and a low pressure cylinder. Exhaust steam of the high pressure cylinder, exhaust steam of the intermediate pressure cylinder and extraction steam of the low pressure cylinder are sequentially numbered as first-level extraction steam, second-level extraction steam and third-level extraction steam which are connected with a first-level heater, a second-level heater and a third-level heater respectively. Part of the exhaust steam of the high pressure cylinder is used as the heating extraction stream of the first-level heater and the remaining exhaust steam enters the intermediate pressure cylinder through a reheater; part of the exhaust steam of the intermediate pressure cylinder is used as the second-level extraction steam and the remaining exhaust steam enters the low pressure cylinder. The heat rate measurement method for the reheating regeneration combined cycle unit includes the following steps that the non-dimensional heat rate and the rate of regeneration work of a reheating non-regenerative cycle are acquired; the heat rate of the reheating regeneration combined cycle unit is determined. According to the heat rate measurement method, the heat rate of the unit is measured according to detection values of inlet parameters, outlet parameters and generated power of the high pressure cylinder, the intermediate pressure cylinder and the low pressure cylinder of the turbine, and detection parameters necessary for measuring the heat rate are reduced.

Description

The heat consumption rate assay method of reheating backheat combined-circulation unit

Technical field

The present invention relates to a kind of assay method of the heat consumption rate for reheating embrittlement, can be used for the hard measurement of reheating backheat combined-circulation unit heat consumption rate, belong to hard measurement field.

Background technology

Reheating embrittlement heat consumption rate is the important indicator of reflection Turbo-generator Set efficiency, traditional measuring method is based on heat balance principle, except measuring main steam condition, reheated steam parameter, each cylinder outlet parameter and generated output, also need to measure pressure of extracted steam from turbine and temperature, and then by the relevant regenerative steam share of measuring and calculating and unit heat consumption, measure unit heat consumption rate.

When needs unit heat rate forecast, due to the extraction pressure corresponding with main steam condition, reheated steam parameter and generated power forecasting value and temperature prediction value cannot be obtained, traditional measuring method is caused to lose efficacy.

Summary of the invention

Technical matters to be solved by this invention is for above-mentioned the deficiencies in the prior art, and a kind of the measurement needing the high, medium and low cylinder pressure of steam turbine to import and export parameter and generated output (or prediction) value is proposed, just can by calculate reheating embrittlement without backheat dimensionless heat consumption rate and backheat work done ratio, and then measure the new method of (or predict) reheating embrittlement heat consumption rate.

For solving the problems of the technologies described above, the technical solution used in the present invention is:

A heat consumption rate assay method for reheating backheat combined-circulation unit, the steam turbine of described Cycle Unit is made up of high pressure cylinder, intermediate pressure cylinder and low pressure (LP) cylinder; High pressure cylinder steam discharge, intermediate pressure cylinder steam discharge and low pressure (LP) cylinder number consecutively of drawing gas is that the first order, the second level and the third level are drawn gas, and be connected with third level well heater with the first order, the second level respectively, primary heater is surface heater, it is hydrophobic discharged to second level well heater, second level well heater is contact(-type) heater, third level well heater is surface heater, and it is hydrophobic discharged to condenser hotwell; High pressure cylinder steam discharge is except the heating being used as primary heater is drawn gas, all the other enter intermediate pressure cylinder through reheater, and intermediate pressure cylinder steam discharge is except being used as the second level and drawing gas, and remainder enters low pressure (LP) cylinder, it is characterized in that, the determination step of the heat consumption rate of described reheating backheat combined-circulation unit is as follows:

Step 1: obtain the dimensionless heat consumption rate HR of reheating without extraction cycle _rKand X is compared in backheat work done _r,

Step 2: the heat consumption rate HR determining reheating backheat combined-circulation unit _{rH & RG}:

Wherein, η _mgit is the product of mechanical efficiency and efficiency of generator in Turbo-generator Set.

Described dimensionless heat consumption rate HR _rKacquisition methods as follows:

Step 1: obtain following data: reheating embrittlement high pressure cylinder throttle (steam) temperature t ₀with initial steam pressure p ₀; Exhaust temperature of HP t _hcwith exhaust steam pressure p _hc; Intermediate pressure cylinder throttle (steam) temperature t _rwith initial steam pressure p _r; Intermediate pressure cylinder exhaust temperature t _mcwith exhaust steam pressure p _mc; Low pressure (LP) cylinder exhaust steam pressure p _c;

Step 2: by reheating embrittlement high pressure cylinder throttle (steam) temperature t ₀with initial steam pressure p ₀, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate high pressure cylinder admission enthalpy h ₀; By exhaust temperature of HP t _hcwith exhaust steam pressure p _hc, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate high pressure cylinder steam discharge enthalpy h _hc; By intermediate pressure cylinder throttle (steam) temperature t _rwith initial steam pressure p _r, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate intermediate pressure cylinder admission enthalpy h _r, by intermediate pressure cylinder exhaust temperature t _mcwith exhaust steam pressure p _mc, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate intermediate pressure cylinder exhaust enthalpy h _mc; According to the pipeline crushing δ between mesolow cylinder, calculate low pressure (LP) cylinder initial steam pressure p _l=p _mcδ; Because in mesolow earthen pipe road, steam enthalpy remains unchanged, therefore low pressure (LP) cylinder steam admission enthalpy h _l=h _mc; According to low pressure (LP) cylinder steam admission enthalpy hl and low pressure (LP) cylinder initial steam pressure p _l, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate the entropy s of low pressure (LP) cylinder admission _l; Low pressure (LP) cylinder constant entropy steam discharge entropy s _c ^*=s _l; By low pressure (LP) cylinder exhaust steam pressure p _cwith constant entropy steam discharge entropy s _c ^*, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate constant entropy exhaust enthalpy h _c ^*; According to low pressure (LP) cylinder efficiency eta under each design conditions _lPthe low pressure (LP) cylinder efficiency eta that rate of load condensate is corresponding under off-design behaviour is obtained by linear interpolation formula _lP; By low pressure (LP) cylinder internal efficiency ratio η _lP, calculate actual exhaust enthalpy h _c=h _r-η _lP(h _r-h _c ^*); By low pressure (LP) cylinder exhaust steam pressure p _c, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate condensate water enthalpy h _wc;

Step 3: according to heat consumption rate definition, obtain the dimensionless heat consumption rate of reheating without extraction cycle:

${\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}$

Wherein, σ is reheater caloric receptivity, σ=h _r-h _hc, h _hcfor high pressure cylinder steam discharge enthalpy, h _rfor reheated steam enthalpy, h _wcfor condensate water enthalpy.

X is compared in described backheat work done _racquisition methods as follows:

According to each design conditions next time hotwork merit compare X _robtain by linear interpolation formula the backheat work done that rate of load condensate is corresponding under off-design behaviour and compare X _r.

Heat consumption rate refers to the heat that specific electric power consumes, and its unit is kJ/kWh.

Dimensionless heat consumption rate refers to the heat that the work done in steam turbine of unit steam flow consumes, and its unit is kJ/kJ.

For the circulation of reheating without backheat, its dimensionless heat consumption rate HR _rKfor:

${\mathrm{HR}}_{\mathrm{RK}}=\frac{(h_0-h_{\mathrm{wc}}+\mathrm{\σ})}{(h_0-h_c+\mathrm{\σ})}---\left(1\right)$

In formula, h ₀for high pressure cylinder steam admission enthalpy, σ are the caloric receptivity of unit share reheated steam in reheater, h _cfor low pressure (LP) cylinder exhaust enthalpy, h _wcfor condensate water enthalpy.

For the Steam Power Circulation of reheating embrittlement, can be considered the compound that the circulation of backheat steam flow circulates with reheating condensing stream.

In this combined-circulation, the circulation of backheat steam flow is its dimensionless heat consumption rate of the circulation HR without cold source energy _r=1; And the circulation of condensing stream has cold source energy, be equivalent to the circulation of reheating without backheat, its dimensionless heat consumption rate is identical with (1), namely ${\mathrm{HR}}_c={\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}.$

According to the definition of Turbo-generator Set heat consumption rate, for the Steam Power Circulation of reheating embrittlement, the heat consumption rate HR of Turbo-generator Set _{rH & RG}the computation model measured is derived as follows:

In formula, η _mgbe the mechanical efficiency of Turbo-generator Set and the product of efficiency of generator, be taken as constant η according to design data herein _mg=0.96.

In formula, W is Turbo-generator Set generated energy, w _rthe amount of work of backheat steam flow circulation, w _cthe amount of work of condensing stream circulation, and $W=\frac{(w_r+w_c){\mathrm{\η}}_{\mathrm{mg}}}{3600}.$

In formula, Q is Steam Turbine circulation heat, HR _rheat consumption rate, the HR of the circulation of backheat steam flow _cthe heat consumption rate of condensing stream circulation, and Q=w _rhR _r+ w _chR _c.

Wherein, HR _r=1, ${\mathrm{HR}}_c={\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}.$

By backheat work done than definition substitution formula (2) can obtain:

Assay method of the present invention not only letter has lacked the necessary detected parameters of the soft mensuration of reheating embrittlement heat consumption rate; According to the predicted value of the high, medium and low cylinder pressure outlet parameter of steam turbine and generated output, the prediction of unit heat consumption rate can also be realized.

The invention has the advantages that:

(1) the present invention obtains new reheating embrittlement heat consumption rate rating model according to strict derivation of Turbo-generator Set heat consumption rate definition, and the result of calculation that this model and traditional thermal equilibrium Calculating model obtain is completely the same; (2) import and export the detected value of parameter and generated output according to the high, medium and low cylinder pressure of steam turbine, achieve the mensuration of unit heat consumption rate, letter has been lacked heat consumption rate and has been measured necessary detection parameter; (3) import and export the predicted value of parameter and generated output according to the high, medium and low cylinder pressure of steam turbine, the predicted value of unit heat consumption rate can be obtained.

Accompanying drawing explanation

Fig. 1 is the calculation process schematic diagram of reheating embrittlement heat consumption rate assay method of the present invention.

Fig. 2 is the reheating backheat steam turbine structure figure that the present invention uses.

Embodiment

A reheating backheat combined-circulation unit heat consumption rate assay method, its computation model is the reheating embrittlement for three grades of backheats.This steam turbine is made up of high pressure cylinder, intermediate pressure cylinder and low pressure (LP) cylinder; High pressure cylinder steam discharge, intermediate pressure cylinder steam discharge and low pressure (LP) cylinder number consecutively of drawing gas is that the 1st grade, the 2nd grade and 3rd level draw gas, and be connected with 3rd level well heater with the 1st grade, the 2nd grade respectively, 1st grade of well heater is surface heater, it is hydrophobic discharged to the 2nd grade of well heater, 2nd grade of well heater is contact(-type) heater, 3rd level well heater is surface heater, and it is hydrophobic discharged to condenser hotwell; High pressure cylinder steam discharge is except the heating being used as the 1st grade of well heater is drawn gas, and all the other enter intermediate pressure cylinder through reheater, and intermediate pressure cylinder steam discharge is except being used as the 2nd grade and drawing gas, and remainder enters low pressure (LP) cylinder.

Determination step is as follows,

Step 1: the calculating of the first whole thermal parameter again of circulation

Step 1.1: (100% load, 75% load, 50% load, 40% load, 30% load) low pressure (LP) cylinder efficiency eta under taking each design conditions _lP(seeing attached list 1), obtains corresponding low pressure (LP) cylinder efficiency eta according to rate of load condensate by linear interpolation formula under off-design behaviour _lP.Under taking each design conditions, X is compared in (100% load, 75% load, 50% load, 40% load, 30% load) backheat work done _r(seeing attached list 2), obtains corresponding backheat work done according to rate of load condensate by linear interpolation formula and compares X under off-design behaviour _r.Take the mechanical efficiency of turbine LP rotors and the product η of efficiency of generator _mg=0.96.Take pipeline crushing δ=1% between intermediate pressure cylinder and low pressure (LP) cylinder.

Unit low pressure (LP) cylinder efficiency under each rate of load condensate of table 1

Table 2 design conditions next time hotwork merit compare the relation with rate of load condensate

Rate of load condensate %

100

75

50

40

30

x r

0.16739

0.15526

0.13347

0.12500

0.12005

Step 1.2: from the database of SIS in Thermal Power PlantQ SIS or distributed monitoring control system, obtain following data: reheating embrittlement high pressure cylinder throttle (steam) temperature t ₀with initial steam pressure p ₀; Exhaust temperature of HP t _hcwith exhaust steam pressure p _hc; Intermediate pressure cylinder throttle (steam) temperature t _rwith initial steam pressure p _r; Intermediate pressure cylinder exhaust temperature t _mcwith exhaust steam pressure p _mc; Low pressure (LP) cylinder exhaust steam pressure p _c.

Step 1.3: by reheating embrittlement high pressure cylinder throttle (steam) temperature t ₀with initial steam pressure p ₀according to the industrial properties of water and steam model IAPWS-IF97 (Association for the Properties of Water and Steam) of international water and steam character association in 1997 proposition, calculate high pressure cylinder admission enthalpy h ₀; By exhaust temperature of HP t _hcwith exhaust steam pressure p _hc, according to IAPWS-IF97, calculate high pressure cylinder steam discharge enthalpy h _hc; By intermediate pressure cylinder throttle (steam) temperature t _rwith initial steam pressure p _r, according to IAPWS-IF97, calculate intermediate pressure cylinder admission enthalpy h _r.By intermediate pressure cylinder exhaust temperature t _mcwith exhaust steam pressure p _mc, according to IAPWS-IF97, calculate intermediate pressure cylinder exhaust enthalpy h _mc; According to the pipeline crushing δ between mesolow cylinder, calculate low pressure (LP) cylinder initial steam pressure p _l=p _mcδ; Because in mesolow earthen pipe road, steam enthalpy remains unchanged, therefore low pressure (LP) cylinder steam admission enthalpy h _l=h _mc; According to low pressure (LP) cylinder steam admission enthalpy h _lwith low pressure (LP) cylinder initial steam pressure p _l, according to IAPWS-IF97, calculate the entropy s of low pressure (LP) cylinder admission _l.Low pressure (LP) cylinder constant entropy steam discharge entropy s _c ^*=s _l.By low pressure (LP) cylinder exhaust steam pressure p _cwith constant entropy steam discharge entropy s _c ^*, according to IAPWS-IF97, calculate constant entropy exhaust enthalpy h _c ^*.By low pressure (LP) cylinder internal efficiency ratio η _lP, calculate actual exhaust enthalpy h _c=h _r-η _lP(h _r-h _c ^*); By low pressure (LP) cylinder exhaust steam pressure p _c(this parameter is condenser saturation pressure), according to IAPWS-IF97, calculates condensate water enthalpy h _wc.

Step 2: calculate the dimensionless heat consumption rate HR of reheating without extraction cycle _rK

The high pressure cylinder steam discharge enthalpy h obtained by step 1 _hc, intermediate pressure cylinder admission enthalpy h _r, calculate and obtain reheater caloric receptivity σ=h _r-h _hc.

Then according to definition, obtain the dimensionless heat consumption rate of reheating without extraction cycle:

${\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}---\left(1\right)$

Step 3: according to:

Wherein η _mgbe the product of mechanical efficiency and efficiency of generator in Turbo-generator Set, be taken as constant η according to design data herein _mg=0.96, calculate the heat consumption rate of reheating backheat combined-circulation unit.

There is for diagram the reheating embrittlement of three grades of backheats.This steam turbine is made up of high pressure cylinder, intermediate pressure cylinder and low pressure (LP) cylinder; High pressure cylinder steam discharge, intermediate pressure cylinder steam discharge and low pressure (LP) cylinder number consecutively of drawing gas is that the 1st grade, the 2nd grade and 3rd level draw gas, and be connected with 3rd level well heater with the 1st grade, the 2nd grade respectively, 1st grade of well heater is surface heater, it is hydrophobic discharged to the 2nd grade of well heater, 2nd grade of well heater is contact(-type) heater, 3rd level well heater is surface heater, and it is hydrophobic discharged to condenser hotwell; High pressure cylinder steam discharge is except the heating being used as the 1st grade of well heater is drawn gas, and all the other enter intermediate pressure cylinder through reheater, and intermediate pressure cylinder steam discharge is except being used as the 2nd grade and drawing gas, and remainder enters low pressure (LP) cylinder.

Detailed calculation procedure is as follows:

Example 1:100% load design conditions

(1) calculating of the first whole thermal parameter again of circulation

According to subordinate list 1 low pressure (LP) cylinder internal efficiency ratio η under 100% rate of load condensate _lPbe 0.84;

According to subordinate list 2 100% rate of load condensate next time hotwork merit compare X _rbe 0.16739;

From the real-time data base of plant level supervisory information system (SIS), read relevant real time data, the main real time data of reading is as follows:

High pressure cylinder initial steam pressure p ₀for 13.5Mpa;

High pressure cylinder throttle (steam) temperature t ₀it is 535 DEG C;

High pressure cylinder exhaust steam pressure p _hcfor 6.080Mpa;

Exhaust temperature of HP t _hcit is 415.2 DEG C;

Intermediate pressure cylinder initial steam pressure p _rfor 5.594Mpa;

Intermediate pressure cylinder throttle (steam) temperature t _rit is 535 DEG C;

Intermediate pressure cylinder exhaust steam pressure p _mcfor 1.6Mpa;

Intermediate pressure cylinder exhaust temperature t _mcit is 359.9 DEG C;

Low pressure (LP) cylinder exhaust steam pressure p _cfor 0.005Mpa;

Can obtain according to IAPWS-IF97 and computation model:

High pressure cylinder steam admission enthalpy h ₀=3426.274kJ/kg

High pressure cylinder exhaust enthalpy h _hc=3215.414kJ/kg

Intermediate pressure cylinder steam admission enthalpy h _r=3509.948kJ/kg

Low pressure (LP) cylinder steam admission enthalpy h _l=3167.643kJ/kg

Low pressure (LP) cylinder constant entropy exhaust enthalpy h _c ^*=2167.943kJ/kg

Low pressure (LP) cylinder exhaust enthalpy h _c=h _l-η _lP(h _l-h _c ^*)=2327.895kJ/kg

Condensate water enthalpy h _wc=137.765kJ/kg

(2) reheating is calculated without extraction cycle dimensionless heat consumption rate HR _rK

Calculating reheater recepts the caloric: σ=h _r-h _hc=294.534kJ/kg

Calculate the dimensionless heat consumption rate of reheating without extraction cycle:

${\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}=2.57234$

(3) unit heat consumption rate HR is calculated _{rH & RG}:

Example 2:60% load condition (prediction)

(1) calculating of the first whole thermal parameter again of circulation

Low pressure (LP) cylinder internal efficiency ratio η under 60% rate of load condensate is obtained by interpolation formula according to subordinate list 1 _lPbe 0.86484;

According to subordinate list 2 by interpolation formula obtain 60% rate of load condensate next time hotwork merit compare X _rbe 0.14219;

According to taking data as follows:

High pressure cylinder initial steam pressure p ₀for 8.1Mpa;

High pressure cylinder throttle (steam) temperature t ₀it is 535 DEG C;

High pressure cylinder exhaust steam pressure p _hcfor 3.355Mpa;

Exhaust temperature of HP t _hcit is 416.6 DEG C;

Intermediate pressure cylinder initial steam pressure p _rfor 3.086Mpa;

Intermediate pressure cylinder throttle (steam) temperature t _rit is 535 DEG C;

Intermediate pressure cylinder exhaust steam pressure p _mcfor 0.991Mpa;

Intermediate pressure cylinder exhaust temperature t _mcit is 359.4 DEG C;

Low pressure (LP) cylinder exhaust steam pressure p _cfor 0.00367Mpa;

Can obtain according to IAPWS-IF97 and computation model:

High pressure cylinder steam admission enthalpy h ₀=3484.263kJ/kg

High pressure cylinder exhaust enthalpy h _hc=3263.699kJ/kg

Intermediate pressure cylinder steam admission enthalpy h _r=3534.927kJ/kg

Low pressure (LP) cylinder steam admission enthalpy h _l=3178.309kJ/kg

Low pressure (LP) cylinder desirable constant entropy exhaust enthalpy h _c ^*=2213.485kJ/kg

Low pressure (LP) cylinder exhaust enthalpy h _c=h _c-η _lP(h _c-h _c ^*)=2343.892kJ/kg

Condensate water enthalpy h _wc=115.118kJ/kg

(2) reheating is calculated without extraction cycle dimensionless heat consumption rate HR _rK

Calculating reheater recepts the caloric: σ=h _r-h _hc=271.228kJ/kg

Calculate the dimensionless heat consumption rate of reheating without extraction cycle:

${\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}=2.57890$

(3) unit heat consumption rate HR is calculated _{rH & RG}:

Example 3:100% load design conditions Traditional calculating methods

(1) calculating of the first whole thermal parameter again of circulation

According to subordinate list 1 low pressure (LP) cylinder internal efficiency ratio η under 100% rate of load condensate _lPbe 0.84;

From the real-time data base of plant level supervisory information system (SIS), read relevant real time data, the main real time data of reading is as follows:

Main steam pressure p ₀for 13.5Mpa;

Main steam temperature t ₀it is 535 DEG C;

High pressure cylinder exhaust steam pressure p _hcfor 6.080Mpa;

Exhaust temperature of HP t _hcit is 415.2 DEG C;

Reheated steam pressure p _rfor 5.594Mpa;

Reheat steam temperature t _rit is 535 DEG C;

Intermediate pressure cylinder exhaust steam pressure p _mcfor 1.6Mpa;

Intermediate pressure cylinder exhaust temperature t _mcit is 359.9 DEG C;

Low pressure (LP) cylinder exhaust steam pressure p _cfor 0.005Mpa;

1st grade of extraction temperature t ₁it is 415.2 DEG C;

1st grade of extraction pressure p ₁for 6.080Mpa;

1st grade of heater condensate temperature t _d1it is 274.5 DEG C;

1st grade of heater outlet coolant-temperature gage t _w1it is 272.5 DEG C;

1st grade of heater outlet water pressure p _w1for 13.500Mpa;

2nd grade of extraction temperature t ₂it is 359.9 DEG C;

2nd grade of extraction pressure p ₂for 1.600Mpa;

2nd grade of heater outlet coolant-temperature gage t _w2it is 199.9 DEG C;

2nd grade of heater outlet water pressure p _w2for 1.552Mpa;

3rd level extraction temperature t ₂it is 152.7 DEG C;

3rd level extraction pressure p ₂for 0.200Mpa;

3rd level heater condensate temperature t _d3it is 119.3 DEG C;

3rd level heater outlet coolant-temperature gage t _w3it is 117.3 DEG C;

3rd level heater outlet water pressure p _w3for 1.552Mpa;

Can obtain according to IAPWS-IF97 and computation model:

Main steam enthalpy h ₀=3426.274kJ/kg

High pressure cylinder steam discharge enthalpy h _hc=3215.414kJ/kg

Reheated steam enthalpy h _r=3509.948kJ/kg

Reheater caloric receptivity σ=h _r-h _hc=294.534kJ/kg

Low pressure (LP) cylinder steam admission enthalpy h _l=3167.643kJ/kg

Low pressure (LP) cylinder constant entropy exhaust enthalpy h _c ^*=2167.943kJ/kg

Low pressure (LP) cylinder exhaust enthalpy h _c=h _l-η _lP(h _l-h _c ^*)=2327.895kJ/kg

Condensate water enthalpy h _wc=137.765kJ/kg

The 1st grade of enthalpy h that draws gas ₁=3215.414kJ/kg

1st grade of heater condensate enthalpy h _d1=1207.950kJ/kg

1st grade of heater outlet water enthalpy h _w1=1195.240kJ/kg

The 2nd grade of enthalpy h that draws gas ₂=3167.643kJ/kg

2nd grade of heater outlet water enthalpy h _w2=852.023kJ/kg

3rd level draws gas enthalpy h ₃=2774.591kJ/kg

3rd level heater condensate enthalpy h _d3=500.602kJ/kg

3rd level heater outlet water enthalpy h _w3=493.080kJ/kg

(2) share of drawing gas at different levels, condensing stream share is calculated

1st grade of well heater draws gas share ${\mathrm{\α}}_1=\frac{h_{w1}-h_{w2}}{h_1-h_{d1}}=0.170971$

2nd grade of well heater draws gas share ${\mathrm{\α}}_2=\frac{(h_{w2}-h_{w3})-{\mathrm{\α}}_1(h_{d1}-h_{w3})}{h_2-h_{w2}}=0.088508$

3rd level well heater draws gas share ${\mathrm{\α}}_3=\frac{(1-{\mathrm{\α}}_1-{\mathrm{\α}}_2)(h_{w3}-h_{\mathrm{wc}})}{h_3-h_{\mathrm{wc}}}=0.099786$

Condensing stream share ${\mathrm{\α}}_c=1-\underset{j=1}{\overset{3}{\mathrm{\Σ}}}{\mathrm{\α}}_j=0.640735$

(3) steam turbine work done, circulation heat is calculated

1st grade of well heater draws gas work done w ₁=α ₁(h ₀-h ₁)=36.051kJ/kg

2nd grade of well heater draws gas work done w ₂=α ₂(h ₀-h ₂+ σ)=48.960kJ/kg

3rd level well heater draws gas work done w ₃=α ₃(h ₀-h ₃+ σ)=94.419kJ/kg

Condensing stream work done w _c=α _c(h ₀-h _c+ σ)=892.488kJ/kg

Steam turbine work done w _i=w ₁+ w ₂+ w ₃+ w _c=1071.918kJ/kg

Circulation heat q ₀=h ₀-h _wc+ (1-α ₁) σ=2475.212kJ/kg

(4) unit heat consumption rate is calculated

Unit heat consumption rate

Claims (3)

1. a heat consumption rate assay method for reheating backheat combined-circulation unit, the steam turbine of described Cycle Unit is made up of high pressure cylinder, intermediate pressure cylinder and low pressure (LP) cylinder; High pressure cylinder steam discharge, intermediate pressure cylinder steam discharge and low pressure (LP) cylinder number consecutively of drawing gas is that the first order, the second level and the third level are drawn gas, and be connected with third level well heater with the first order, the second level respectively, primary heater is surface heater, it is hydrophobic discharged to second level well heater, second level well heater is contact(-type) heater, third level well heater is surface heater, and it is hydrophobic discharged to condenser hotwell; High pressure cylinder steam discharge is except the heating being used as primary heater is drawn gas, all the other enter intermediate pressure cylinder through reheater, and intermediate pressure cylinder steam discharge is except being used as the second level and drawing gas, and remainder enters low pressure (LP) cylinder, it is characterized in that, the determination step of the heat consumption rate of described reheating backheat combined-circulation unit is as follows:

Step 1: obtain the dimensionless heat consumption rate HR of reheating without extraction cycle _rKand X is compared in backheat work done _r,

Step 2: the heat consumption rate HR determining reheating backheat combined-circulation unit _{rH & RG}:

Wherein, η _mgit is the product of mechanical efficiency and efficiency of generator in Turbo-generator Set.

2. the heat consumption rate assay method of reheating backheat combined-circulation unit according to claim 1, is characterized in that, described dimensionless heat consumption rate HR _rKacquisition methods as follows:

Step 1: obtain following data: reheating embrittlement high pressure cylinder throttle (steam) temperature t ₀with initial steam pressure p ₀; Exhaust temperature of HP t _hcwith exhaust steam pressure p _hc; Intermediate pressure cylinder throttle (steam) temperature t _rwith initial steam pressure p _r; Intermediate pressure cylinder exhaust temperature t _mcwith exhaust steam pressure p _mc; Low pressure (LP) cylinder exhaust steam pressure p _c;

Step 2: by reheating embrittlement high pressure cylinder throttle (steam) temperature t ₀with initial steam pressure p ₀, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate high pressure cylinder admission enthalpy h ₀; By exhaust temperature of HP t _hcwith exhaust steam pressure p _hc, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate high pressure cylinder steam discharge enthalpy h _hc; By intermediate pressure cylinder throttle (steam) temperature t _rwith initial steam pressure p _r, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate intermediate pressure cylinder admission enthalpy h _r, by intermediate pressure cylinder exhaust temperature t _mcwith exhaust steam pressure p _mc, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate intermediate pressure cylinder exhaust enthalpy h _mc; According to the pipeline crushing δ between mesolow cylinder, calculate low pressure (LP) cylinder initial steam pressure p _l=p _mcδ; Because in mesolow earthen pipe road, steam enthalpy remains unchanged, therefore low pressure (LP) cylinder steam admission enthalpy h _l=h _mc; According to low pressure (LP) cylinder steam admission enthalpy h _lwith low pressure (LP) cylinder initial steam pressure p _l, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate the entropy s of low pressure (LP) cylinder admission _l; Low pressure (LP) cylinder constant entropy steam discharge entropy s _c ^*=s _l; By low pressure (LP) cylinder exhaust steam pressure p _cwith constant entropy steam discharge entropy s _c ^*, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate constant entropy exhaust enthalpy h _c ^*; According to low pressure (LP) cylinder efficiency eta under each design conditions _lPthe low pressure (LP) cylinder efficiency eta that rate of load condensate is corresponding under off-design behaviour is obtained by linear interpolation formula _lP; By low pressure (LP) cylinder internal efficiency ratio η _lP, calculate actual exhaust enthalpy h _c=h _r-η _lP(h _r-h _c ^*); By low pressure (LP) cylinder exhaust steam pressure p _c, according to the industrial properties of water and steam model of international water and steam character association in 1997 proposition, calculate condensate water enthalpy h _wc;

Step 3: according to heat consumption rate definition, obtain the dimensionless heat consumption rate of reheating without extraction cycle:

${\mathrm{HR}}_{\mathrm{RK}}=\frac{h_0-h_{\mathrm{wc}}+\mathrm{\σ}}{h_0-h_c+\mathrm{\σ}}$

Wherein, σ is reheater caloric receptivity, σ=h _r-h _hc, h _hcfor high pressure cylinder steam discharge enthalpy, h _rfor reheated steam enthalpy, h _wcfor condensate water enthalpy.

3. the heat consumption rate assay method of reheating backheat combined-circulation unit according to claim 1, it is characterized in that, X is compared in described backheat work done _racquisition methods as follows:

According to each design conditions next time hotwork merit compare X _robtain by linear interpolation formula the backheat work done that rate of load condensate is corresponding under off-design behaviour and compare X _r.