CN217004429U - System for recovering wet water of boiler for industrial steam supply - Google Patents

Abstract

The utility model discloses a system for recovering boiler wet water for industrial steam supply, which is provided with a flash tank and an electric heater, wherein high-energy saturated water generated in the wet operation of a boiler is flashed into saturated steam under the pressure of industrial steam supply, the temperature is raised to the temperature of the industrial steam supply, and the saturated steam is finally supplied to the outside, so that the recovery of working media and energy of the wet water is realized, and the operation economy of a unit is greatly improved. Meanwhile, the utility model has the advantages of small transformation range, low cost, short investment recovery period and feasibility in finance.

Description

A system for recovering boiler wet water for industrial steam supply

technical field

The utility model belongs to the field of cogeneration of heat and power for coal-fired generating sets, in particular to a system for recycling boiler wet water for industrial steam supply.

Background technique

With the rapid development of clean, low-carbon, and renewable energy such as solar energy, wind energy, and water energy, traditional thermal power has rapidly transformed from the main energy source of power generation to the guaranteed energy source. Large thermal power units urgently need to undertake the task of deep power grid peak regulation. With the transformation and upgrading of industries and the improvement of people's living standards, the demand for heat such as industrial steam and central heating is growing rapidly. Among them, in the field of industrial steam supply, in order to meet the normal operation of steam users, the parameters of industrial steam supply are required to be continuous, stable and reliable. However, when the unit operates under low load, the main and auxiliary equipment seriously deviate from the design conditions, which is difficult to achieve. Ensure the reliability of the combined heat and power system. Therefore, the contradiction between the deep peak shaving demand of thermal power units and the guarantee of steam supply capacity has become increasingly prominent.

When the large thermal power unit is deeply peaked to the extent that the boiler load is less than about 30% BMCR, the heat in the furnace cannot heat all the feed water entering the water wall into saturated steam, and the boiler turns to wet operation. After the steam-water mixture from the water-cooled wall system enters the separator, the centrifugal force generated by the rotation separates the steam-water, the separated steam is led out from the top of the separator to the low-temperature superheater, and the water enters the water storage tank from the bottom of the separator. When the water quality is qualified, the nearly saturated water in the water storage tank is discharged into the condenser, causing a lot of energy loss; when the water quality is unqualified, the nearly saturated water in the water storage tank is discharged out of the plant through the sewage system, causing a large amount of work. mass loss and energy loss.

Since the water collected in the water storage tank is near-saturated water under the feed water pressure when the boiler is operating in wet state, the energy quality is high, and it is necessary to recycle it for reuse. Therefore, under the situation of long-term low-load operation of thermal power units and the difficulty of maintaining the quality of steam supply, a retrofit method of recycling boiler wet water for high-pressure industrial steam supply is proposed.

SUMMARY OF THE INVENTION

The purpose of the utility model is to solve the problem that the existing thermal power unit is in deep peak regulation to low load, and the wet water separated by the steam-water separator cannot be effectively used when the boiler is running in a wet state, which leads to the problem of poor economy in the low-load operation of the unit, and alleviates the problem of the unit at the same time. Due to the contradiction between long-term low-load operation and the difficulty of guaranteeing the quality of industrial steam supply, high-energy wet water is recycled for high-pressure industrial steam supply, and a system for recovering boiler wet water for industrial steam supply is provided.

In order to achieve the above purpose, the utility model includes a steam-water separator, a water storage tank, a flash tank and an electric heater;

The inlet of the steam-water separator is connected to the steam-water mixture of the water wall system, the saturated water outlet of the steam-water separator is connected to the water storage tank, the water storage tank is connected to the flash tank, and the saturated steam outlet of the flash tank is connected to the electric heater.

The saturated steam outlet of the steam-water separator is connected to the low-temperature superheater.

The saturated water outlet of the flash tank is connected to the condenser.

A stop valve is arranged on the connection pipeline between the water storage tank and the flash tank.

An electric regulating valve is arranged on the connecting pipeline between the water storage tank and the flash tank.

The electric heater is used to heat the saturated steam produced by the flash tank to the industrial steam supply temperature and supply it to the outside.

Compared with the prior art, the utility model is provided with a flash tank and an electric heater. First, the high-energy saturated water generated during the wet operation of the boiler is flashed into saturated steam under the industrial steam supply pressure, and the temperature is raised to the industrial steam supply temperature. , and finally supplied to the outside world, realizing the recovery of the working fluid and energy of the wet water, and greatly improving the operating economy of the unit. At the same time, the utility model has the advantages of small transformation scope, low cost, short investment recovery period and financial feasibility.

Description of drawings

Fig. 1 is the system structure diagram of the present utility model;

Among them, 1. Steam-water separator, 2. Water storage tank, 3. Globe valve, 4. Electric regulating valve, 5. Flash tank, 6. Electric heater, 7. Condenser.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings.

Referring to Figure 1, the present utility model includes a steam-water separator 1, a water storage tank 2, a flash tank 5 and an electric heater 6;

The inlet of the steam-water separator 1 is connected to the steam-water mixture of the water wall system, the saturated water outlet of the steam-water separator 1 is connected to the water storage tank 2, and the saturated steam outlet of the steam-water separator 1 is connected to the low temperature superheater. The water storage tank 2 is connected to the flash tank 5 , and the connection pipeline between the water storage tank 2 and the flash tank 5 is provided with a stop valve 3 and an electric regulating valve 4 . The saturated steam outlet of the flash tank 5 is connected to the electric heater 6 . The saturated water outlet of the flash tank 5 is connected to the condenser 7 . The electric heater 6 is used to heat the saturated steam generated by the flash tank to the industrial steam supply temperature and supply it to the outside.

The working method of the present utility model comprises the following steps:

When the unit is running in a wet state, the steam-water mixture from the water-cooled wall system enters the steam-water separator 1, producing saturated wet-state water under a certain amount of feed water pressure, and the saturated wet-state water is collected in the water storage tank 2; the saturated wet-state water separated by the steam-water separator 1 The steam enters the low temperature superheater.

The saturated wet water in the water storage tank 2 enters the flash tank 5 through the outlet pipe;

After flashing in the flash tank 5, saturated water and saturated steam under the required industrial steam supply pressure are generated, and the saturated steam enters the electric heater 6. The saturated water produced after flashing in the flash tank 5 is discharged into the condenser 7 .

The saturated steam is heated to the industrial steam supply temperature in the electric heater 6 and supplied to the outside.

Example:

The steam turbine of a 1000MW unit in a power plant is an N1000-25/600/600 type, ultra-supercritical, single-shaft, four-cylinder, four-exhaust, one-time intermediate reheat, condensing steam turbine manufactured by Dongfang Steam Turbine Co., Ltd., and it needs to undertake industrial steam supply. The parameters are 2.5MPa, 320℃.

When the boiler is running in wet state with 20% THA load, the generating power of the unit is 205.2MW, producing about 120t/h of high-energy saturated water (pressure is 13.6MPa, temperature is 334.4℃). After the utility model is transformed, a flash tank and an electric heater are installed. The design pressure of the flash tank is 2.5MPa, the saturated steam pressure after flashing is 2.5MPa, the temperature is 224°C, and the flow rate is 39.1t/h. After heating by an electric heater, it is further heated up to 320°C and then supplied to the outside.

After the utility model is transformed and recovered, the heat consumption rate of the unit is about 8817.6kJ/kWh (the equivalent coal consumption rate is about 330.3g/kWh) when the unit is running in a wet state under 25% THA condition, which is 9330.8kJ/kWh compared to the unit before the reconstruction. kWh (equivalent coal consumption rate is about 349.6g/kWh) decreased by about 513.2kJ/kWh (equivalent coal consumption rate is about 19.3g/kWh), a decrease of 5.5%, which greatly improves the operating economy of the unit.

Claims (6)

1. A system for recovering wet water of a boiler for industrial steam supply is characterized by comprising a steam-water separator (1), a water storage tank (2), a flash tank (5) and an electric heater (6);

the inlet of the steam-water separator (1) is connected with a steam-water mixture of a water wall system, the saturated water outlet of the steam-water separator (1) is connected with the water storage tank (2), the water storage tank (2) is connected with the flash tank (5), and the saturated steam outlet of the flash tank (5) is connected with the electric heater (6).

2. A system for recovering wet water of a boiler for industrial steam supply according to claim 1, characterized in that the saturated steam outlet of the steam-water separator (1) is connected with a low-temperature superheater.

3. A system for recovering boiler wet water for industrial steam supply according to claim 1, characterized in that the saturated water outlet of the flash tank (5) is connected to a condenser (7).

4. A system for recovering boiler wet water for industrial steam supply according to claim 1, characterized in that a stop valve (3) is arranged on the connection pipeline between the water storage tank (2) and the flash tank (5).

5. A system for recovering boiler wet water for industrial steam supply according to claim 1, characterized in that an electric regulating valve (4) is arranged on the connection pipeline between the water storage tank (2) and the flash tank (5).

6. A system for recovering wet water of a boiler for industrial steam supply according to claim 1, characterized in that the electric heater (6) is used for heating the saturated steam generated by the flash tank (5) to the industrial steam supply temperature and supplying the saturated steam to the outside.

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