CN205261619U - A fan heater drainage system for overcritical and ultra supercritical unit - Google Patents

Abstract

A heater drainage system for supercritical and ultra-supercritical units is proposed, which belongs to the field of heater design. In this system, the steam output from the heater will enter the drain cooler of the heater after passing through the steam trap of the heater, and will be connected with the booster pump from the condensed water to the waste heat utilization device of the flue gas that enters the drain cooler of the heater. The pumped condensate undergoes heat exchange, after which the steam will enter the exhaust or condenser. This solution solves the problems of high failure rate and poor energy-saving effect of the existing system, and has many advantages such as safety, reliability and improved energy utilization efficiency.

Description

Heater drainage system for supercritical and ultra-supercritical units

technical field

The utility model belongs to the technical field of air heater design, in particular to an air heater drainage system used for supercritical and ultra-supercritical units.

Background technique

The air heater uses steam to heat the air at the inlet of the air preheater, so that the temperature of the air entering the air preheater rises, and the wall temperature of the air preheater rises, so as to avoid low-temperature corrosion and dust blocking of the air preheater and ensure the safety of the boiler Stable operation. At present, the heater drainage system used in supercritical and ultra-supercritical thermal power plants has many faults in the system that can recover heat, and the commissioning rate is low, which affects the safe and stable operation of the boiler.

At present, there are two heater drainage methods commonly used in supercritical and ultra-supercritical power plants: one is the deaerator method shown in Figure 1a, and the system flow is heater-drain tank-drain pump-deaerator; the other One is the steam removal device (or condenser) method shown in Figure 1b, and the system flow is heater-steam trap-condenser. In Figure 1a, the steam passes through the steam regulating valve 1 of the primary heater, and the steam regulating valve 2 of the secondary heater respectively enters the primary heater 3 and the secondary heater 4, and then passes through the drain tank 5 of the heater and the heater Drainage pump 6 of the device enters the deaerator 7 or to the boiler start-up drainage expansion vessel or to the fixed row expansion vessel 8; in Figure 1b, the steam enters through the primary heater steam regulating valve 1 and the secondary heater steam regulating valve 2 respectively. The primary heater 3, the secondary heater 4, and then pass through the primary heater automatic steam trap 5 and the secondary heater automatic steam trap 6 to enter the exhaust device or condenser 8 or to the boiler start-up drain expander or to a fixed Expansion container 9.

There are some problems in the above two methods. For the deaerator method, heat can be recovered. The drain pump of the air heater needs to consume electric energy. The system is relatively complicated. The drain pump of the air heater is frequently started and stopped, and the cavitation of the drain pump is serious. The failure rate of the drainage pump is high, and the maintenance workload is large, which affects the safe and stable operation of the boiler; the drainage of the air heater is directly transported to the deaerator without passing through the condensate polishing system. It cannot be guaranteed, which affects the safe operation of the boiler; for the exhaust steam removal device, the system is simple and the heat recovery is less, and the water quality of the boiler feed water for supercritical and ultra-supercritical units is guaranteed. It is a commonly used heater in power plants. Hydrophobic method, but the heat recovered by this method is only the heat of the difference between the condensed water temperature and the make-up water temperature, the heat loss is more, and the energy-saving effect is not good.

Utility model content

The purpose of the utility model is to provide a heater drainage system suitable for supercritical and ultra-supercritical units, so as to overcome the problems in the prior art.

In order to achieve the above purpose, the utility model proposes a heater drainage system for supercritical and ultra-supercritical units. In the heater drainage system for supercritical and ultra-supercritical units, the primary heater One end of the steam regulating valve of the air heater and the steam regulating valve of the secondary air heater receives steam through a pipe; the other end of the steam regulating valve of the primary air heater and the steam regulating valve of the secondary air heater are respectively connected to the primary air heater and the secondary air heater Secondary air heater; the primary air heater is connected to the primary air heater steam trap through pipes, and the secondary air heater is connected to the secondary air heater steam trap through pipes; the primary air heater steam trap and the secondary air heater drain The devices are collected to the first main pipe through their respective pipelines; the first main pipe is then divided into the first sub-pipe and the second sub-pipe, the first sub-pipe is connected to the boiler start-up drain expansion vessel or fixed row expansion vessel through the isolation valve, and the second sub-pipe The sub-pipe is connected to the first end of the front isolating valve of the air heater drain cooler; the second end of the front isolating valve of the air heater drain cooler is connected to the first inlet of the air heater drain cooler; The first outlet of the cooler is connected to the first end of the isolation valve after the drain cooler of the heater; the second end of the isolation valve after the drain cooler of the heater is connected to the exhaust device or the condenser through a pipeline; The air drain cooler also includes a second inlet and a second outlet. The second inlet receives the condensed water from the condensed water pumped by the booster pump of the flue gas waste heat utilization device through the condensed jelly pipe, and the second outlet is connected to the flue gas through a pipe. The waste heat utilization device is used to realize the heat exchange between the steam from the direction of the isolation valve in front of the drain cooler of the air heater and the condensed water.

According to one aspect of the present invention, the system further includes a bypass valve of the heater drain cooler, and the first end of the heater drain cooler bypass valve is connected to the front partition of the heater drain cooler through a pipe. The first end of the valve and the second end of the heater drain cooler bypass valve are connected to the second end of the heater drain cooler rear block valve through a pipe.

It can be seen that this system is simple and convenient to implement, with smooth flow and low failure rate. It can effectively recover the heat of the heater drain, save energy and reduce consumption, and meet the national requirements for improving the comprehensive utilization efficiency of energy. All of them pass through the condensate polishing treatment device to meet the high standards of boiler feed water quality for supercritical and ultra-supercritical units. In winter, it can be raised to the condensate temperature of the flue gas waste heat utilization device, meeting the requirement that the condensate water temperature of the flue gas waste heat utilization device is greater than 66 degrees, and can be popularized and applied in power plants.

Description of drawings

Fig. 1a is a structural schematic diagram of the first heater hydrophobic method in the prior art;

Fig. 1b is a schematic structural diagram of the second heater hydrophobic method in the prior art;

Fig. 2 is a schematic diagram of a heater drainage system for supercritical and ultra-supercritical units according to an embodiment of the present invention.

detailed description

The following descriptions are preferred implementation examples of the present utility model, and therefore do not limit the protection scope of the present utility model.

As shown in Figure 2, according to one embodiment, in the heater drainage system for supercritical and ultra-supercritical units, the steam regulating valve 201 of the primary heater and the steam regulating valve 202 of the secondary heater pass through the pipeline Receiving steam; the steam regulating valve 201 of the primary air heater and the steam regulating valve 202 of the secondary air heater are respectively connected to the primary air heater 203 and the secondary air heater 204 through pipelines; the primary air heater 203 is connected to the The primary heater steam trap 208 and the secondary heater 204 are connected to the secondary heater steam trap 209 through pipelines; the primary heater steam trap 208 and the secondary heater steam trap 209 are collected to the secondary heater steam trap through their respective pipeline A main pipe 212; the first main pipe 212 is then divided into the first sub-pipe and the second sub-pipe, the first sub-pipe is connected to the boiler start-up drainage expansion vessel or the fixed row expansion vessel 213 through the isolation valve, and the second sub-pipe is connected to the heating The first end of the front cut-off valve 210 of the air heater drain cooler; the second end of the front cut-off valve 210 of the heater drain cooler 210 is connected to the first inlet of the heater drain cooler 205; the heater drain cooler The first outlet of 205 is connected to the first end of the block valve 211 after the drain cooler of the air heater; the second end of the block valve 211 after the drain cooler of the heater is connected to the exhaust device or the condenser 214 through a pipeline; The heater drain cooler 205 also includes a second inlet and a second outlet. The second inlet receives the condensate pumped from the condensed water to the booster pump 206 of the flue gas waste heat utilization device through the condensed jelly pipe, and the second outlet passes through the pipeline It is connected to the flue gas waste heat utilization device 215 to realize the heat exchange between the steam from the direction of the front isolation valve 210 of the drain cooler of the air heater and the condensed water.

According to one embodiment, it also includes a heater drain cooler bypass valve 207, the first end of which is connected to the first end of the front block valve 210 of the heater drain cooler through a pipeline, the heater drain cooler bypass valve The second end of 207 is connected to the second end of the shut-off valve 211 after the drain cooler of the air heater through a pipe.

In this way, the outlet air temperature of the heater is controlled by adjusting the steam volume of the primary heater 203 and the secondary heater 204 through the steam regulating valve 201 of the primary heater and the steam regulating valve 202 of the secondary heater. Heat is exchanged in the primary heater 203 and the secondary heater 204 and enters the heater drain cooler 205 through the primary heater steam trap 208 and the secondary heater steam trap 209, heating from the condensate jellyfish pipe to the flue gas The condensed water of the waste heat utilization device uses the heater drain cooler to realize the deep recovery of the heater drain heat, and the heat is discharged to the exhaust device after the deep recovery; Use in case of hydrophobic cooler accidents. When the unit starts and the water quality is poor, the heater drains to the boiler start-up drain expander.

It can be seen that the scheme is equipped with a flue gas waste heat utilization device 205 to deeply recover the heat of the heater to drain water, reduce heat loss, realize energy saving and emission reduction, and improve energy utilization efficiency; the condensed water to the flue gas waste heat utilization device is used to cool the warm air Drainage device, waste heat utilization of flue gas can recover the loss of exhaust gas, which meets the upgrading requirements of national energy conservation and emission reduction. Condensed water is used as cooling water source, and the temperature of condensed water to the flue gas waste heat utilization device is generally required to be greater than 66 degrees, and the temperature of condensed water is low in winter , the use of flue gas waste heat utilization device can not only increase the temperature of condensed water, but also deeply recycle and reuse the water. The condensed water is led from the turbine room to the furnace in the boiler room and just passes through the heater arranged in the boiler room, so there is no need to connect pipes for the drain cooler of the heater, which saves pipeline investment. The condensate booster pump from the condensate to the flue gas waste heat utilization device is used as the booster pump, and there is no need to set up a separate pump for the condensate to the drain cooler of the air heater, and the system is simple. Condensed water is used to cool the heater to drain water and recover heat, and the heater drains to return to the exhaust device or condenser. The heater drain is all passed through the condensate polishing device, which affects the quality of boiler feed water for supercritical and ultra-supercritical units. Provides protection and improves the safety of boiler operation.

It should be noted that the specific implementation methods and application fields proposed by the utility model are only for the purpose of illustration, and are not used as limitations on the protection scope of the utility model. Those skilled in the art can modify the specific implementation methods of the utility model to meet actual needs .

Claims (2)

1. for a draining system for steam air heater of utility overcritical and ultra supercritical unit, it is characterized in that:

Described for draining system for steam air heater of utility overcritical and ultra supercritical unit, steam air heater steam control valve and twoOne end of inferior steam air heater steam control valve receives steam by pipeline; Steam air heater steam control valve and secondary steam air heater steamThe other end of control valve is connected to respectively steam air heater and secondary steam air heater by pipeline; No. one time steam air heater is connected to by pipelineA steam air heater steam trap, secondary steam air heater is connected to secondary steam air heater steam trap by pipeline; Steam air heater steam trap and twoInferior steam air heater steam trap is by the female pipe of pipe influx to the first separately; After first female pipe, be divided into the first son pipe and the second son pipe,The first sub-pipe is connected to boiler starting hydrophobic expanding container or is surely arranged flash vessel by isolating valve,, and it is hydrophobic that the second sub-pipe is connected to steam air heaterThe first end of isolating valve, before cooler; It is hydrophobic cooling that the second end of the front isolating valve, of described steam air heater drain cooler is connected to steam air heaterThe first entrance of device; The first outlet of steam air heater drain cooler is connected to the first end of isolating valve, after steam air heater drain cooler;After steam air heater drain cooler, the second end of isolating valve, is connected to steam exhaust device or condenser by pipeline; Described steam air heater is hydrophobic coldBut device also comprises the second entrance and the second outlet, and the second entrance receives from condensate water to fume afterheat utilization by the jellyfish pipe that condensesThe condensate water that device booster pumps into, the second outlet is connected to flue gas waste heat utilization device by pipeline, to realize from steam air heaterThe steam of isolating valve, direction and the heat exchange of described condensate water before drain cooler.

2. according to claim 1 for draining system for steam air heater of utility overcritical and ultra supercritical unit, it is characterized in that:

Described system also comprises steam air heater drain cooler bypass valve, and the first end of described steam air heater drain cooler bypass valve passes throughPipeline is connected to the first end of the front isolating valve, of steam air heater drain cooler, and the second end of steam air heater drain cooler bypass valve is by pipeRoad is connected to the second end of isolating valve, after steam air heater drain cooler.