CN102536345B - Method for increasing running energy efficiency of BPRT (blast furnace power recovery turbine) system - Google Patents

Abstract

The invention relates to energy efficiency analysis technology, and aims to provide a method for increasing running energy efficiency of a BPRT (blast furnace power recovery turbine) system. The method includes (1) gradually adjusting opening of a butterfly valve of an inlet of a turbomachine under the condition that coal gas flow is not changed, and selecting the opening of the butterfly valve when the current of a motor is the lowest or energy efficiency of the turbomachine is the highest as the best opening; (2) changing a coal gas flow condition, repeating the experiment, and building a mathematical model of the corresponding relation of coal gas flow and the opening of the butterfly valve; and (3) obtaining the corresponding best opening of the butterfly valve of the inlet via the mathematical model according to the coal gas flow in a running process of the BPRT system, controlling the butterfly valve of the inlet of the turbomachine according to the best opening, and accordingly realizing that the BPRT system runs in an energy efficiency optimum state. The method can be used for people to comprehensively know running conditions of the turbomachine, effectively reduces errors of energy efficiency calculation data due to noise caused by sampling, calculates the opening of the butterfly valve of the inlet in an optimizing manner, and improves the energy efficiency of the BPRT system.

Description

A kind of method that improves BPRT system operational energy efficiency

Technical field

The present invention relates to a kind of method of operational energy efficiency of the blast furnace gas energy recovery system (Blast Furnace Power Recovery Turbine is called for short BPRT) that improves turbine engine Driven by Coaxial blower.In particular, be the optimization of carrying out operational energy efficiency for the BPRT system of blast furnace.

Background technique

Metallurgical process industry is the energy, various raw-material producer, is also the main consumer of the energy, energy-saving and cost-reducing most important.China's metallurgical industry comprehensive energy consumption level is far above global average level.

Ironmaking system is the general name of the operations such as coking, sintering, ironmaking.The energy that this system directly consumes accounts for 70% left and right of Steel Complex's total energy consumption, is the energy-conservation emphasis of Steel Complex.Blast Furnace Blower System is as the heart of ironmaking system, and its energy consumption also occupies the major component of ironmaking system.Blast furnace air consumption proportion in Iron-smelting energy consumption is larger.Blast furnace air energy consumption accounts for Iron-smelting energy consumption 10%～15%.Therefore the energy-saving and cost-reducing of Blast Furnace Blower System had great importance for the energy-saving and emission-reduction of metallurgy industry.

BPRT system is the abbreviation of the blast furnace gas energy recovery system of turbine engine Driven by Coaxial blower.This device is by introducing turbine engine by blast furnace gas, drive turbine engine arbor to rotate, directly Driven by Coaxial blast furnace blower, the original bulky systems of TRT is simplified to be merged, cancel generator and be transported to electric system, merge robot control system(RCS), lubricating oil system, power oil system etc., and the energy of recovery is directly replenished to axle as rotating mechanical energy fasten, avoid the loss of transformation of energy, make the motor of blower reduce electric current and energy-conservation.Therefore at China's steel industry high speed development and today of energy wretched insufficiency, for the supporting BPRT system of blast furnace becomes the main path that energy Conservation of Blast Furnace reduces discharging gradually.

At present BPRT system is all the Driven by Coaxial of simply carrying out turbine engine and blower, and turbine engine efficiency problem is not also optimized, and the often low spot in efficiency has affected the efficiency of energy utilization of BPRT system.

Summary of the invention

The technical problem to be solved in the present invention is, overcomes deficiency of the prior art, and a kind of method of the BPRT of raising system operational energy efficiency is provided.

For solving its technical problem, solution of the present invention is:

A kind of method that the BPRT of raising system operational energy efficiency is provided, comprises the following steps:

(1), in the situation that keeping gas flow constant, progressively adjust the aperture of turbine engine entrance butterfly valve; The current of electric of corresponding turbine engine efficiency and blower while recording different valve opening; Choose butterfly valve opening when the highest of current of electric minimum wherein or turbine engine efficiency (minimum for preferentially taking electric current), as the best aperture of this gas flow lower inlet butterfly valve;

(2) change gas flow condition, repeat above-mentioned experiment; Obtaining after enough data, setting up the mathematical model of gas flow and butterfly valve opening corresponding relation;

(3) according to the gas flow in BPRT system running, obtain the best aperture of corresponding entrance butterfly valve by described mathematical model, and the control to turbine engine entrance butterfly valve accordingly, operate in efficiency the optimum state thereby realize BPRT.

In the present invention, described turbine engine efficiency data obtain by following manner:

(1) gather BPRT system operational parameters, comprising: turbine engine inlet flow rate Q _ti(m ³/ s), rate of discharge Q _to(m ³/ s), inlet temperature T _ti(K), outlet temperature T _to(K), air horsepower N (kW);

(2) obtain by following formula the heat (q that turbine engine entrance coal gas is brought into _t1, kW):

$q_{t1}=x_{{\mathrm{CO}}_2}{Q}_{\mathrm{ti}}{c}_{{\mathrm{CO}}_2}^{\mathrm{ti}}+x_{\mathrm{CO}}{Q}_{\mathrm{ti}}{c}_{\mathrm{CO}}^{\mathrm{ti}}+x_{H_2}{Q}_{\mathrm{ti}}{c}_{H_2}^{\mathrm{ti}}+x_{N_2}{Q}_{\mathrm{ti}}{c}_{N_2}^{\mathrm{ti}}+x_{{\mathrm{CH}}_4}{Q}_{\mathrm{ti}}{c}_{{\mathrm{CH}}_4}^{\mathrm{ti}}$

In formula, x _cO, be respectively main component CO in top gas ₂, CO, N ₂, H ₂, CH ₄volume content (%); that temperature is T _titime specific enthalpy (kJ/m ³);

(3) obtain by following formula the heat (q that the turbine engine export coal band of gas enters _t2, kW):

$q_{t2}=x_{{\mathrm{CO}}_2}{Q}_{\mathrm{to}}{c}_{{\mathrm{CO}}_2}^{\mathrm{to}}+x_{\mathrm{CO}}{Q}_{\mathrm{to}}{c}_{\mathrm{CO}}^{\mathrm{to}}+x_{H_2}{Q}_{\mathrm{to}}{c}_{H_2}^{\mathrm{to}}+x_{N_2}{Q}_{\mathrm{to}}{c}_{N_2}^{\mathrm{to}}+x_{{\mathrm{CH}}_4}{Q}_{\mathrm{to}}{c}_{{\mathrm{CH}}_4}^{\mathrm{to}}$

In formula, for temperature is T _tothermal capacitance (kJ/m ³);

(4) obtaining the callable heat of turbine by following formula is (q _tr, kW):

q _tr＝q _t1-q _t2

(5) by the efficiency of following formula acquisition turbine engine:

${\mathrm{\η}}_t=\frac{N}{q_{\mathrm{tr}}}.$

In the present invention, obtaining after the efficiency data of turbine engine, adopting first-order lag filtering algorithm to carry out filtering processing to remove noise to it according to following formula:

${\mathrm{\η}}_b^{\mathrm{nf}}=(1-\mathrm{\α}){\mathrm{\η}}_b^n+\mathrm{\α}{\mathrm{\η}}_b^{\mathrm{nf}-1}$

In formula, represent the filtered value of efficiency of the n time, be the efficiency value of calculating for the n time, represent the filtered value of efficiency of the n-1 time, the span of α is 0～1.

In the present invention, in described step (1), while adjusting the aperture of entrance butterfly valve, its amplitude of accommodation is controlled at 5% to 30% aperture scope.

Compared with prior art, the invention has the beneficial effects as follows:

1, the parameter of importing and exporting by the turbine engine of sampling BPRT system, carry out the Energy Efficiency Analysis of turbine engine, can comprehensively understand the operation conditions of turbine engine thus, thus the real time data of acquisition turbine engine efficiency, convenient operation management and Optimum Operation to turbine engine.

2. utilize first-order lag filtering algorithm, process calculating the efficiency data that obtain, can effectively reduce the efficiency calculated data mistake that the noise that brings due to sampling causes.

3, adopt the mode of data driven, utilize laboratory data to obtain the optimum operation efficiency model of BPRT system, thereby optimize the aperture of calculating import butterfly valve, in raising BPRT system, obtain turbine engine and there is best efficiency.

Brief description of the drawings

Fig. 1 is BPRT system schematic;

Fig. 2 is blast furnace blower Operational Limits instrumentation plan;

Fig. 3 is first-order lag filtering algorithm schematic diagram;

Fig. 4 is the flow chart of filtering algorithm;

Fig. 5 is that schematic diagram is calculated in the optimization of BPRT system operational energy efficiency.

Embodiment

First it should be noted that, the present invention relates to be built in the application of the software function module in computer, is the one application of computer technology in control technique field.Claimant thinks, as reading over application documents, accurate understanding is of the present invention realize principle and goal of the invention after, in conjunction with existing known technology in the situation that, those skilled in the art can use the software programming technical ability of its grasp to realize the present invention completely.Aforementioned software function module comprises but is not limited to: efficiency computing module, first-order lag filtering algorithm module etc., and this category of all genus that all the present patent application files are mentioned, claimant will not enumerate.

Basic principle of the present invention is:

First the parameter during, by the operation of collection turbine engine is also processed.Secondly, utilize the efficiency formula of turbine engine, gathered real time data substitution is carried out to computing, obtain the real-time energy efficiency of turbine engine.In the time that the efficiency of real-time calculating is lower, by adjusting the butterfly valve before turbine engine import, thereby turbine engine efficiency is improved.

In the present invention, wherein turbine engine efficiency is calculated the method that adopts energy balance, because loss part cannot be carried out measurement and calculation, the import and export parameter of turbine engine also can be subject to the impact of noise simultaneously, therefore adopts the mode of first-order filtering to proofread and correct for last efficiency formula.

In the present invention, the method for wherein adjusting the aperture of the butterfly valve before turbine engine import mainly adopts experiment to add the method for data driven.By to the period in the whole cycle of blast furnace operating, first butterfly valve opening is turned down to a certain numerical value, the efficiency that records the turbine engine in the whole operation cycle changes.General this numerical value from 5% to 30%.Service data to record is carried out after analysis modeling, just can obtain the butterfly valve opening after optimization calculating in next operation cycle.

With reference to figures 1 through 5, will describe the present invention below.

Fig. 1 represents the schematic diagram of BPRT system.The High Temperature High Pressure coal gas that blast furnace 2 produces passes through after gravitational dust collecting device 3 and bag-type dust collector 4 udst separations, imports turbine engine 5 and drives turbine shaft to rotate, the mechanical kinetic energy that the High Temperature High Pressure Conversion of Energy that coal gas has is turbine shaft.Exceeded at its rotating speed after the rotating speed of blower 7, clutch 6 engages automatically, thereby mechanical kinetic energy is passed to blower, has so just reduced the power consumption of motor 9, brings hot blast into hot blast stove 1.When coal gas amount changes or turbine engine breaks down, its axle rotating speed is reduced to below blower 7 rotating speeds, clutch 6 automatic trips from, only driven through gearbox 8 belt driven blowers 7 by motor 9, thereby ensured that blower 7 can normally work.

Fig. 2 represents that in the present invention, calculating turbine engine efficiency calculates needed parameter measurement amount, comprising inlet pressure, the temperature of turbine engine, outlet pressure, temperature, flow and air horsepower.Here it should be noted that all measurements all need to meet requirements such as installation of sensors position.

Fig. 3 represents turbine engine efficiency calculation procedure in the present invention.Wherein key step is as described in the summary of the invention part of this specification, and the formula wherein relating to is as follows:

$q_{t1}=x_{{\mathrm{CO}}_2}{Q}_{\mathrm{ti}}{c}_{{\mathrm{CO}}_2}^{\mathrm{ti}}+x_{\mathrm{CO}}{Q}_{\mathrm{ti}}{c}_{\mathrm{CO}}^{\mathrm{ti}}+x_{H_2}{Q}_{\mathrm{ti}}{c}_{H_2}^{\mathrm{ti}}+x_{N_2}{Q}_{\mathrm{ti}}{c}_{N_2}^{\mathrm{ti}}+x_{{\mathrm{CH}}_4}{Q}_{\mathrm{ti}}{c}_{{\mathrm{CH}}_4}^{\mathrm{ti}}$ (formula 1)

$q_{t2}=x_{{\mathrm{CO}}_2}{Q}_{\mathrm{to}}{c}_{{\mathrm{CO}}_2}^{\mathrm{to}}+x_{\mathrm{CO}}{Q}_{\mathrm{to}}{c}_{\mathrm{CO}}^{\mathrm{to}}+x_{H_2}{Q}_{\mathrm{to}}{c}_{H_2}^{\mathrm{to}}+x_{N_2}{Q}_{\mathrm{to}}{c}_{N_2}^{\mathrm{to}}+x_{{\mathrm{CH}}_4}{Q}_{\mathrm{to}}{c}_{{\mathrm{CH}}_4}^{\mathrm{to}}$ (formula 2)

Q _tr=q _t1-q _t2(formula 3)

${\mathrm{\η}}_t=\frac{N}{q_{\mathrm{tr}}}$ (formula 4)

In above-mentioned formula:

N is generated output, and unit is kW; q _trfor the callable heat of turbine engine, unit is kW; q _t1for the enthalpy of turbine engine entrance coal gas, unit is kW; q _t2for the enthalpy of turbine engine outlet coal gas, unit is kW; Main component in top gas is: CO ₂, CO, N ₂, H ₂, CH ₄, its volume content is expressed as x _cO(%), $x_{N_2}(\%),x_{H_2}(\%),x_{{\mathrm{CH}}_4}(\%);c_{{\mathrm{CO}}_2}^{\mathrm{ti}},c_{\mathrm{CO}}^{\mathrm{ti}},c_{H_2}^{\mathrm{ti}},c_{N_2}^{\mathrm{ti}},c_{{\mathrm{CH}}_4}^{\mathrm{ti}}$ That temperature is T _tispecific enthalpy, unit is kJ/m ³; that temperature is T _tothermal capacitance, unit is kJ/m ³; Q _tifor turbine engine inlet flow rate, unit is m ³/ s; Q _tofor turbine engine rate of discharge, unit is m ³/ s;

The error causing in order to eliminate noise, the present invention adopts first-order lag filtering algorithm to carry out filtering to the efficiency of calculating, and removes noise.Filtering algorithm is:

${\mathrm{\η}}_b^{\mathrm{nf}}=(1-\mathrm{\α}){\mathrm{\η}}_b^n+\mathrm{\α}{\mathrm{\η}}_b^{\mathrm{nf}-1}$ (formula 6)

Here represent the filtered value of efficiency of the n time, be the efficiency value of calculating for the n time, represent the filtered value of efficiency of the n-1 time.The value of α, 0 to 1, can be modified according to field condition.Fig. 4 is the flow chart of filtering algorithm.

Fig. 5 represents BPRT system operational energy efficiency Optimal Experimental schematic diagram.Wherein experimental procedure, is mainly by different butterfly valve openings, obtains different current of electric, records the flow that turbine engine is imported and exported simultaneously.The in the situation that of same gas flow, butterfly valve opening when wherein current of electric minimum is most effective with turbine engine according to above three data decimation, as the best butterfly valve opening under this flow.By a large amount of data, set up the mathematical model of gas flow and butterfly valve opening.Therefore in the time moving next time, detect after gas flow, obtain best butterfly valve opening by this model, improve BPRT operational energy efficiency.

Claims (2)

1. a method that improves BPRT system operational energy efficiency, comprises the following steps:

(1), in the situation that keeping gas flow constant, progressively adjust the aperture of turbine engine entrance butterfly valve; The current of electric of corresponding turbine engine efficiency and blower while recording different valve opening; Choose current of electric minimum wherein or the turbine engine efficiency butterfly valve opening when the highest, as the best aperture of this gas flow lower inlet butterfly valve;

(2) change gas flow condition, repeat above-mentioned experiment; Obtaining after enough data, setting up the mathematical model of gas flow and butterfly valve opening corresponding relation;

(3) according to the gas flow in BPRT system running, obtain the best aperture of corresponding entrance butterfly valve by described mathematical model, and the control to turbine engine entrance butterfly valve accordingly, operate in efficiency the optimum state thereby realize BPRT system;

Described turbine engine efficiency data obtain by following manner:

(I) gather BPRT system operational parameters, comprising: turbine engine inlet flow rate Q _ti(m ³/ s), rate of discharge Q _to(m ³/ s), inlet temperature T _ti(K), outlet temperature T _to(K), air horsepower N (kW);

(II) obtain by following formula the heat (q that turbine engine entrance coal gas is brought into _t1, kW):

$q_{t1}=x_{{\mathrm{CO}}_2}{Q}_{\mathrm{ti}}{c}_{{\mathrm{CO}}_2}^{\mathrm{ti}}+x_{\mathrm{CO}}{Q}_{\mathrm{ti}}{c}_{\mathrm{CO}}^{\mathrm{ti}}+x_{H_2}{Q}_{\mathrm{ti}}{c}_{H_2}^{\mathrm{ti}}+x_{N_2}{Q}_{\mathrm{ti}}{c}_{N_2}^{\mathrm{ti}}+x_{{\mathrm{CH}}_4}{Q}_{\mathrm{ti}}{c}_{{\mathrm{CH}}_4}^{\mathrm{ti}}$

In formula, be respectively main component CO in top gas ₂, CO, N ₂, H ₂, CH ₄volume content (%); that temperature is T _titime specific enthalpy (kJ/m ³);

(III) obtain by following formula the heat (q that the turbine engine export coal band of gas goes out _t2, kW):

$q_{t2}=x_{{\mathrm{CO}}_2}{Q}_{\mathrm{to}}{c}_{{\mathrm{CO}}_2}^{\mathrm{to}}+c_{\mathrm{CO}}{Q}_{\mathrm{to}}{c}_{\mathrm{CO}}^{\mathrm{to}}+c_{H_2}{Q}_{\mathrm{to}}{c}_{H_2}^{\mathrm{to}}+x_{N_2}{Q}_{\mathrm{to}}{c}_{N_2}^{\mathrm{to}}+x_{{\mathrm{CH}}_4}{Q}_{\mathrm{to}}{c}_{{\mathrm{CH}}_4}^{\mathrm{to}}$

In formula, for temperature is T _tospecific enthalpy (kJ/m ³);

(IV) obtaining the callable heat of turbine by following formula is (q _tr, kW):

q _tr＝q _t1-q _t2

(V) by the efficiency of following formula acquisition turbine engine:

${\mathrm{\η}}_t=\frac{N}{q_{\mathrm{tr}}};$

Obtaining after the efficiency data of turbine engine, adopting first-order lag filtering algorithm to carry out filtering processing to remove noise to it according to following formula:

${\mathrm{\η}}_b^{\mathrm{nf}}=(1-\mathrm{\α}){\mathrm{\η}}_b^n+\mathrm{\α}{\mathrm{\η}}_b^{\mathrm{nf}-1}$

In formula, represent the filtered value of efficiency of the n time, be the efficiency value of calculating for the n time, represent the filtered value of efficiency of the n-1 time, the span of α is 0～1.

2. method according to claim 1, is characterized in that, in described step (1), while adjusting the aperture of entrance butterfly valve, its amplitude of accommodation is controlled at 5% to 30% aperture scope.