Combined-cycle power plant

 

The invention relates to a power system and can be used in combined-cycle units, designed for the generation of electric energy. A combined cycle gas turbine installation comprising a gas turbine generator and steam boiler with steam low pressure circuit containing at least evaporator low pressure, characterized in that the steam of the low pressure circuit is the output of a couple communicated with the input pair in the setting of the compressor of a gas turbine, which is located in the area of pressure of air above atmospheric. The invention improves the efficiency of the installation. 1 Il.

The invention relates to a power system and can be used in combined cycle plants (CCGT) for the generation of electric energy. The invention is applicable mainly in PSU contact type (KGU).

Thermal energy efficiency PSU of any type, used for generation of electric energy, characterized by the value of efficiency is defined by the formulawhere- Efficiency PSU; N - power PSU; b - fuel consumption; q_t- specific calorific ways the ear; L₀- weight stekhiometricheskie ratio;I_g- reducing the enthalpy of the flue from the waste-heat boiler (HRSG) gases (without summed up in the combustion chamber (CC) and gas turbine (GT) pair) by cooling to ambient temperature;
G_to- flow exhaust steam discharged into the environment or into the condenser;
I_to- reducing the enthalpy of the exhaust steam during condensation and possibly cooled to the initial temperature of the water in the loop;
B_v- air flow through the compressor of the gas turbine unit (GTU).

Maximum efficiency PSU meets the minimum expression
(L₀+1)I_g+L₀G_toI_to/B_v_min, (2)
achieved by reducing the values of the parameters,I_g,I_toand relations of G_to/B_v.

Known KGU (CPGU-16) /1/ (S. 27-28). This KGU contains: GTU DS containing the compressor (consisting of compressor low pressure (CLP) and high pressure (CHP), CS and GT (with the possible (teplotransservise circuit PMC-3100). In KU warmth GT exhaust to produce steam supplied to the input of CC pair (ecological respectively) and to the input of GT for a couple (power injection).

The disadvantage of KGU is a relatively low efficiency level, formed at the initial temperature of the gases before GT 1062^oWith 41 percent, due primarily to high temperature gases at KU (180-200^oC) and, hence, high values ofI_gandI_toin the expression (2) when inflated (for a given gas temperature for GT) ratio G_to/B_vand with the lack of lower values of.
Closest to the present invention is KGU /2/ (S. 53). This KGU contains the compressor, consisting of KND and ARCS, CC, GT, consisting of three turbines and HRSGs with economizer, evaporator and superheater surfaces of the two pressures.

Drafted in the TOP two pairs of pressure is introduced into the COP as additional working the body and is used to cool the blade apparatus (LA) GT, with low pressure steam is used only for open steam cooling turbine, HRSG output on a pair of low pressure communicated through cooling ="https://img.russianpatents.com/chr/916.gif">I_g,I_toin the expression (2), does not improve the efficiency of the PSU, since the amount of steam in the low pressure circuit, due to the high heat capacity of steam, as a rule, exceeds the required amount of refrigerant to an open cooling LA GT in the area of low pressure. Due to the large difference in temperature between the low-pressure steam and products of combustion when mixed into the flowing parts of the turbines is cooled working fluid and the reduction gas temperature exhaust GT. The result is the poor performance of high-pressure steam and the increase of the coefficient of excess airwhen you save the relationship G_k/In_vat a sufficiently high level due to low pressure steam.

The present invention is to increase the efficiency of KGU by reducing the amount of excess air coefficient.
This problem is solved in the present CCGT with gas turbine and HRSG, steam low pressure circuit containing at least evaporator low pressure, due to the fact that steam low pressure circuit indicated by output pair in the input pair in the setting of the compressor of the gas turbine, placed mpressor with air pressure above atmospheric, subsequent doumanian steam in the compressor of the gas turbine up to pressure before GT, overheating in the COP and the expansion in the GT to atmospheric pressure allows you to get more useful work with lower excess air coefficientand thereby increase the efficiency of the PSU.

The invention is explained in the above drawing, which in an example implementation of the invention presents the principal heat flow PSU contact type with the TOP two pressures.

This KGU contains the gas turbine to the compressor 1 and KU two pressure steam low pressure circuit which contains the evaporator 2 low pressure. In this example, the steam of the low pressure circuit also includes a drum 3 low-pressure superheater (suchoparek) 4 low pressure. According to the invention, the steam of the low pressure circuit is reported at the output by the couple through the steam pipe 5 with the input pair in the setting of the compressor 1, placed in the region of the pressure of air above atmospheric. KU in the example provided by the economizer 6 low pressure and 7 high-pressure evaporator 8 high-pressure drum 9 high pressure superheater 10 provided at the outlet for a couple propranololo works as follows.

Condensed from the products of combustion in Vietnam 14 moisture (condensate) served in the economizer 6 low pressure and, further, in the drum 3 low pressure, whence he comes, in part, to the evaporator 2, low pressure, partly through the economizer 7 high pressure in the drum 9 high pressure in the quantity of the evaporative capacity of the evaporator 8 high pressure. On these heat exchange surfaces KU warm exhaust GT 13 of condensate produced two pairs of pressure. High-pressure steam produced in the evaporator 8 high pressure and peregrevaetsya in the superheater 10, is fed through the steam line 11 to the inputs on a couple of COP 12 and GT 13 as a working body. Steam generation in the evaporator 2 low pressure is produced without reducing the performance of high-pressure steam, due to the additional temperature reduction of exhaust from the HRSG gas emissions by decreasing the values of parametersI_gandI_toincluded in the expression (2). Low pressure steam, drained and slightly superheated in the superheater 4 low pressure, is fed through the steam pipe 5 to the compressor 1 GTU in the pressure range above atmospheric, where win up to pressure before GT 13 and the value of the coefficient of excess air. Expansion in GT 13 added to the working fluid is superheated low pressure steam to a pressure close to atmospheric, allows you to get more useful work. The result is increased efficiency PSU.

The example is presented only to illustrate the invention and does not exhaust all possible options for its implementation.

Sources used
1. Combined getprotobyname plant with a capacity of 16 to 25 MW with heat recovery of exhaust gases and regeneration of water from the vapor-gas flow / Novels Century. And., Krivutsa Century A. // Teploenergetika, 4, 1996, S. 27.

2. Combined-cycle power plant with steam injection: opportunities and optimization of parameters loop / Styrikovich M. A., Tabor O. N., Zeigarnik Y. A. and others, " Teploenergetika, 10, 1995, S. 52.

Claims

A combined cycle gas turbine installation comprising a gas turbine generator and steam boiler with steam low pressure circuit containing at least evaporator low pressure, characterized in that the steam of the low pressure circuit is the output of a couple communicated with the input pair in the setting of the compressor of a gas turbine, which is located in the area of pressure air is