CN101504243A - Condensing liquid nitrogen deep-cooling process for turbine - Google Patents

Abstract

The invention relates to a process for deep cooling condensed steam of a steam turbine with liquid nitrogen, which is characterized in that: raw material air enters a nitrogen plant, nitrogen is generated by the nitrogen plant and delivered to a gas-gathering station, and after being boosted by a booster station, the nitrogen enters a refrigerating unit from a manifold of a refrigerator to be refrigerated; liquid nitrogen at 192 DEG C below zero generated by the refrigerating unit enters a liquid nitrogen tank; separated liquid nitrogen is boosted by the booster station after entering a liquid nitrogen collecting box; separated waste gases enter a waste gas collection box and then are discharged into the air; and separated nitrogen are delivered into a nitrogen plant manifold at the inlet of the refrigerator after passing through the booster station. The process has the technical advantages that: as the cooling temperature of the process is 192 DEG C blow zero, cold source loss is reduced and refrigeration efficiency is improved; and adopted liquid nitrogen deep cooling technology can improve exhaust gas condensation efficiency, improve the thermal efficiency of the steam turbine from the current 40 percent to 80 percent, reduce the heat consumption of the steam turbine to 4589.07KJ/kw.h, reduce the power-generating coal consumption by 140g/kw.h for a newly-established power plant and by 80 to 100g/kw.h for an established power plant, and make the thermal efficiency of the unit reach 0.7292.

Description

Condensing liquid nitrogen deep-cooling process for turbine

Technical field

The present invention relates to the thermal power generating technology field, particularly a kind of condensing liquid nitrogen deep-cooling process for turbine that is used for the coal-fired monoblock of the above capacity condensing-type of 300MW.

Background technology

The thermal power plant is to utilize fire coal, oil, the chemical energy of fuel such as natural gas produces the factory of electric energy, in boiler, the chemical energy of fuel changes the rotor rotation of the heat energy and the driving steam turbine of steam into, transfer electric energy to by generator, at present, water in the station boiler water cooling wall enters drum after being heated into steam through coal dust firing, steam in the drum continues heat absorption, become superheated steam, superheated steam has very high pressure and temperature, enter steam turbine through pipeline, the rotor rotation of pushing turbine, form mechanical energy, when rotating, turbine rotor just drives the generator amature rotation, lead cutting magnetic line in the generator unit stator produces induced-current, generator is converted to electric energy with the mechanical energy of steam turbine, electric energy is delivered to the user after transformer boosts, the steam that discharges heat energy is discharged from the steam drain of steam turbine bottom, be called weary gas, weary gas condenses into water after cooled in condenser, send into low-pressure heater and get back in the oxygen-eliminating device through condensate pump, finish a circulation, in the process of circulation, loss of steam and water is arranged, therefore, to in circulation, replenish a certain amount of water in right amount, to guarantee the normal operation of circulation, the problem that it exists is that the coal-fired monoblock thermal efficiency of condensing-type is not high, adopt existing, traditional (rivers water, underground water, seawater, air) cooling technology, the thermal efficiency of its generating is respectively;

300-600MW Subcritical Units thermal efficiency is: 38%-41%.

300-600MW supercritical unit thermal efficiency is: 41%-43%.

600-1000MW ultra supercritical generatine set heat efficiency is: 44%-45%.

The gross efficiency of condensing power plant is;

η _ndc＝η _gl*η _gd*η _oi*η _t*η _jη _d

η _ndc＝3600N _d/B _dQDW

η _NdcThe gross efficiency in-power plant

η _Gl-boiler efficiency

η _Gd-pipeline efficient

η _OiThe internal efficiency ratio of-steam turbine

η _tThe absolute internal efficiency of-steam turbine

η _jThe mechanical efficiency of-steam turbine

η _dThe efficient of-generator

η _NdcThe efficient in-power plant

By aforementioned calculation formula and heat balance diagram as can be seen the condensing-type generating set effectively utilize degree very low to fuel thermal energy, main cause is that to enter the exhaust steam amount of gas trap in the exhaust steam condensation process excessive, the sink temperature height, have little time a large amount of exhaust steam of condensation, cause most of evaporation loss, the heat that coagulates the coal-fired monoblock about 60% of gas formula has scattered and disappeared by gas trap, cause turbine efficiency on the low side, thermal loss of steam turbine is higher, and the gross coal consumption rate of unit is high, therefore, improve turbine efficiency, reduce gross coal consumption rate, must seek new cooling medium, the cooling system that exploitation makes new advances farthest reduces the thermal loss by gas trap.

Summary of the invention

The purpose of this invention is to provide a kind of novel cooling medium, improve cooling capacity and minimizing condensing liquid nitrogen deep-cooling process for turbine by the thermal loss of gas trap.

The present invention is achieved in that and it is characterized in that:

(1), raw air enters nitrogen factory, produces nitrogen by nitrogen factory and is sent to gas gathering station, through booster station boosts after, enter refrigeration unit and cool off by the female pipe of refrigeration machine;

(2), produce-192 ℃ liquid nitrogen through refrigeration unit and enter liquid nitrogen container, the liquid nitrogen of liquid nitrogen container enters the total header of liquid nitrogen by parallel female pipe, enter the secondary influent header through the one-level influent header again, in the liquid nitrogen gas trap, be provided with S type condenser pipe, become gas-liquid mixture after the liquid nitrogen acting in the S type condenser pipe;

(3), enter the one-level outlet header, entering gas-liquid separation device, to carry out liquid nitrogen separated from the gas, and the liquid nitrogen after the separation is boosted by booster station after entering liquid nitrogen collecting box through the secondary outlet header;

(4), the liquid nitrogen one tunnel that boosted by booster station enters the female pipe of refrigeration machine inlet, another road enters liquid nitrogen container;

(5), separated waste gases enters waste gas collection box, enters atmosphere then;

(6), isolated N ₂, NO ₂, NO gas enters N respectively ₂, NO ₂, the NO gas fractionation unit, isolated NO, NO ₂The steel cylinder of packing into, separated nitrogen are sent into the female pipe of nitrogen factory of refrigeration machine inlet behind booster station.

Technological merit of the present invention is;

(1), chilling temperature is low, cooling capacity is strong, the minimum chilling temperature of existing cooling system is that cooling effectiveness is low more than 4 ℃, and chilling temperature of the present invention is-192 ℃, has reduced cold source energy, has improved condensation efficiency.

(2), the condenser that uses at present is to be made of 14676 straight line titanium pipes, consumed a large amount of alloy pipes, and condenser of the present invention only need be with 72 S type condenser pipes compositions.

(3), adopt liquid nitrogen deep but technology can improve the condensation efficiency of weary gas, the thermal efficiency that makes steam turbine brings up to 80% by present 40%, thermal loss of steam turbine can be reduced to 4589.07KJ/kw.h, the gross coal consumption rate new power plant construction can reduce 140g/kw.h, built up power plant and can reduce by 80-100g/kw.h, the thermal efficiency of unit reaches 0.7292.

Table 1 is the comparison of interior vapour pressure blocking solution nitrogen of low pressure (LP) cylinder and existing cooling medium data;

Annotate vapour pressure resistance in the low pressure (LP) cylinder; Characterize the comprehensive capacity for work of steam in cylinder, the big more steam turbine capacity for work of interior vapour pressure resistance is strong more

Description of drawings

Below in conjunction with accompanying drawing invention is described further;

Fig. 1 is a condensing-type coal-burning power plant production process schematic diagram,

Fig. 2 is the heat balance diagram of condensing-type generating set,

Fig. 3 is the condensing liquid nitrogen deep-cooling process for turbine flow chart,

Fig. 4 is the liquefaction of nitrogen process chart,

Fig. 5 is the structure of condenser schematic diagram.

The specific embodiment

Shown in Fig. 1-5

Design condition;

33 ℃ of temperature

Relative humidity 80%

Atmospheric pressure 101Kpa (A)

Raw air impurity routine

Carbon dioxide (CO ₂)≤400ppm

Acetylene (C ₂H ₂)≤1ppm

Hydrogen (H ₂)≤1ppm

Carbon monoxide (CO)≤1ppm

The public work condition

Recirculated cooling water

Inflow temperature≤32 ℃

Leaving water temperature≤40.5 ℃

Intake pressure 0.25Mpa (G)

Discharge pressure 0.15Mpa (G)

PH value 7 one 8

Suspension 2mg/L

Total hardness 145mg/L (CaCO ₃)

(1), raw air enters nitrogen factory (nitrogen factory exerts oneself: 10000M ³/ h), produce 99.99% nitrogen by nitrogen factory and be sent to gas gathering station, after booster station boosts, enter the female pipe of refrigeration machine inlet nitrogen factory, enter the refrigeration machine cooling again by the female pipe of refrigeration machine, the refrigeration machine peak power is 2000KW, 2 operations, 2 standby, emergency duties, the liquid nitrogen of producing-192 ℃ through refrigeration unit is stored in 6 liquid nitrogen containers, and 3 liquid nitrogen containers are one group, one group of operation, one group standby, and each liquid nitrogen container capacity is 25 tons

(2), liquid nitrogen enters 3 parallel mother's pipes through the liquid nitrogen container outlet and enters the total header of liquid nitrogen again, enter 8 secondary influent headers through 4 one-level influent headers again, each secondary influent header enters 9 S type condenser pipes in the gas trap by 9 contact pipeline correspondences, and the liquid nitrogen in the S type condenser pipe carries out sufficient condensation and finishes heat exchange and become the back and become liquid-vapor mixture entering exhaust steam in the gas trap;

(3), gas-liquid mixture enters secondary outlet header, one-level outlet header through 9 contact pipelines, entering gas-liquid separation device again, to carry out liquid nitrogen separated from the gas, the liquid nitrogen after the separation enters liquid nitrogen collecting box and is boosted by booster station;

(4), the liquid nitrogen one tunnel that boosted by booster station enters the female pipe of refrigeration machine inlet, another road enters liquid nitrogen container;

(5), separated waste gases enters waste gas collection box, enters atmosphere then;

(6), isolated N ₂, NO ₂, NO gas enters N respectively ₂, NO ₂, the NO gas fractionation unit, isolated NO, the NO steel cylinder of packing into, separated nitrogen is sent into the female pipe of nitrogen factory of refrigeration machine inlet behind booster station.

Claims (2)

1, a kind of condensing liquid nitrogen deep-cooling process for turbine, the present invention is achieved in that and it is characterized in that:

(1), raw air enters nitrogen factory, produces nitrogen by nitrogen factory and is sent to gas gathering station, through booster station boosts after, enter refrigeration unit and cool off by the female pipe of refrigeration machine;

(2), produce-192 ℃ liquid nitrogen through refrigeration unit and enter liquid nitrogen container, the liquid nitrogen of liquid nitrogen container enters the total header of liquid nitrogen by parallel female pipe, enter the secondary influent header through the one-level influent header again, in the liquid nitrogen gas trap, be provided with S type condenser pipe, become gas-liquid mixture after the liquid nitrogen acting in the S type condenser pipe;

(3), enter the one-level outlet header, entering gas-liquid separation device, to carry out liquid nitrogen separated from the gas, and the liquid nitrogen after the separation is boosted by booster station after entering liquid nitrogen collecting box through the secondary outlet header;

(4), the liquid nitrogen one tunnel that boosted by booster station enters the female pipe of refrigeration machine inlet, another road enters liquid nitrogen container;

(5), separated waste gases enters waste gas collection box, enters atmosphere then;

(6), isolated N ₂, NO ₂, NO gas enters N respectively ₂, NO ₂, the NO gas fractionation unit, isolated NO, NO ₂The steel cylinder of packing into, separated nitrogen are sent into the female pipe of nitrogen factory of refrigeration machine inlet behind booster station.

2, the described condensing liquid nitrogen deep-cooling process for turbine of root a tree name claim 1, the cooling medium that it is characterized in that condenser is a liquid nitrogen.

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