CN111408230A - Wastewater recoverable integrated treatment system and method suitable for coal-fired power plant - Google Patents

Abstract

The invention provides a waste water recyclable integrated treatment system and method suitable for coal-fired power plants, including an air preheater, a smoke dust separator, a stirring type flue gas dryer, a sludge separation device, a condenser and a drying guide. Fan, wherein the flue gas inlet of the air preheater is connected to the flue gas outlet of the coal-fired boiler; the flue gas outlet of the air preheater is connected to the inlet of the soot separator, and the sludge outlet of the soot separator is connected to the stirring type flue gas The inlet of the dryer, the dry sludge outlet of the stirring flue gas dryer is connected to the inlet of the sludge separation device, and the sludge outlet of the sludge separation device is connected to the feed inlet of the coal-fired boiler; the sludge separation The flue gas outlet of the device is connected to the hot end inlet of the condenser, and the hot end outlet of the condenser is connected to the outlet of the air preheater through the drying induced draft fan; the stirring type flue gas dryer is provided with a wet sludge inlet; The invention can increase the overall thermal efficiency of the boiler.

Description

A waste water recyclable integrated treatment system and method suitable for coal-fired power plants

technical field

The invention belongs to the technical field of power generation, and in particular relates to a waste water recyclable integrated treatment system and method suitable for a coal-fired power station.

Background technique

my country's sewage is divided into two parts: industry and urban life. From 2010 to 2017, my country's industrial sewage discharge basically maintained at about 20 billion tons per year, and urban domestic sewage discharge increased from 35.4 billion tons to about 60 billion tons. According to statistics, in 2017, the sludge treatment market size has exceeded 50 billion yuan. According to the "Notice on Carrying out the Pilot Work of Coal-fired Coupling Biomass Power Generation Technology Reform (2017)" of the National Energy Administration, it is suggested that coal-fired power stations should assist in the processing of biomass fuels such as straw and sludge.

The "Emission Standard of Pollutants for Urban Sewage Treatment Plants" (GB18918) requires that the moisture content of dewatered sludge is not more than 80%. However, the coal-fired boiler is limited by the fuel delivery system and design conditions, and cannot be mixed with urban sludge with high moisture content. Therefore, the sludge needs to be dried before it can be sent to the coal-fired boiler for blending.

The current coal-fired power station sludge co-processing process is mainly designed for dryers, and the waste water after drying is mainly passed directly into the boiler tail flue. Because the boiler induced draft fan has the maximum air volume that can be handled, all the steam after a certain amount of water enters the boiler, which will affect the load capacity of the boiler.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a waste water recyclable integrated treatment system and method suitable for coal-fired power stations, which solves the above-mentioned technical defects of the existing coal-fired power station sludge co-processing devices.

In order to achieve the above object, the technical scheme adopted in the present invention is:

The invention provides a waste water recyclable integrated treatment system suitable for coal-fired power plants, comprising an air preheater, a smoke dust separator, a stirring type flue gas dryer, a sludge separation device, a condenser and a drying induced draft fan, Wherein, the flue gas inlet of the air preheater is connected to the flue gas outlet of the coal-fired boiler; the flue gas outlet of the air preheater is connected to the inlet of the soot separator, and the sludge outlet of the soot separator is connected to the stirring type flue gas dryer The inlet of the agitated flue gas dryer is connected to the inlet of the sludge separation device, and the sludge outlet of the sludge separation device is connected to the feed port of the coal-fired boiler; The flue gas outlet is connected to the hot end inlet of the condenser, and the hot end outlet of the condenser is connected to the outlet of the air preheater through the drying induced draft fan; the stirring type flue gas dryer is provided with a wet sludge inlet.

Preferably, a sludge storage silo is connected to the wet sludge inlet of the stirring type flue gas dryer; a push-type transmission device is arranged between the stirring type flue gas dryer and the sludge storage bin.

Preferably, a mixing device is arranged between the flue gas outlet of the condenser and the drying induced draft fan; the mixing device is connected with the flue gas outlet of the soot separator.

Preferably, the cold end of the condenser is connected with an external circulating water device; the bottom of the condenser is provided with a waste water outlet.

Preferably, a conveying fan is provided between the sludge outlet of the sludge separation device and the coal-fired boiler.

A waste water recyclable integrated treatment method suitable for coal-fired power plants, based on the described wastewater recyclable integrated treatment system suitable for coal-fired power plants, includes the following steps:

The flue gas entering the air preheater from the tail flue of the coal-fired boiler passes through the residual heat to form medium and high temperature flue gas, and then enters the flue dust separator for separation. The separated dust is mixed with wet sludge and sent to the The agitated sludge dryer is dried, and the dried sludge enters the sludge separation device for separation. After separation, the sludge is sent to the coal-fired boiler for combustion; the flue gas separated by the sludge separation device is sent to the top outlet. To the condenser, the flue gas entering the condenser is cooled and sent to the outlet of the air preheater.

Preferably, the temperature of the flue gas at the flue gas inlet of the air preheater is greater than or equal to 300°C.

Preferably, the flue gas cooled by the condenser and the medium-high temperature flue gas separated by the soot separator enter the mixing device for mixing, and then are sent to the outlet of the air preheater.

Compared with the prior art, the beneficial effects of the present invention are:

The invention provides a waste water recyclable urban sludge integrated treatment system and method suitable for coal-fired power plants, which utilizes the heat of a coal-fired boiler to dry urban wet sludge, and sends the dried dry sludge to the boiler for combustion ; Through this process, the urban sludge is co-processed, and the calorific value of the sludge can also be used for power generation in coal-fired power stations to promote the development of regional circular economy; due to the limited output of the induced draft fan in the coal-fired power station, the system will dry the water vapor after drying. Perform separate cooling and removal treatment; through this system, the drying process will not affect the load capacity of the boiler, and because the amount of water vapor entering the boiler is reduced, the overall thermal efficiency of the boiler can also be increased.

Description of drawings

1 is a schematic structural diagram of a processing system involved in the present invention;

Among them, 1. coal-fired boiler 2, air preheater 3, soot separator 4, sludge storage bin 5, Jiaolong pusher 6, feeding port 7, discharging port 8, stirring flue gas dryer 9, sludge Separation device 10, condenser 11, mixing device 12, drying induced draft fan 13, conveying fan 14, waste water pit

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings.

As shown in FIG. 1, the present invention provides a waste water recyclable urban sludge integrated treatment system suitable for coal-fired power plants, including a coal-fired boiler 1, an air preheater 2, a soot separator 3, and a sludge storage silo. 4. Jiaolong pusher 5, feeding port 6, discharging port 7, stirring flue gas dryer 8, sludge separation device 9, condenser 10, mixing device 11, drying induced draft fan 12, conveying fan 13 and waste water Pit 14, wherein the flue gas outlet of the coal-fired boiler 1 is connected to the flue gas inlet of the air preheater 2, and the flue gas outlet of the air preheater 2 is connected to the flue gas inlet of the soot separator 3. The outlet is connected to the mixing device 11 and the feed port 6 on the stirring type flue gas dryer 8 respectively.

The feed port 6 on the stirring type flue gas dryer 8 is also connected with the discharge port of the sludge storage bin 4 .

A push-type transmission device is arranged between the feeding port and the sludge storage bin 4 .

The discharge port 7 on the stirring type flue gas dryer 8 is connected with the feed port of the sludge separation device 9 .

The bottom of the sludge separation device 9 is provided with a sludge outlet, and the sludge outlet is connected to the feed port of the coal-fired boiler 1 .

A conveying fan 13 is provided between the sludge outlet of the sludge separation device 9 and the feed inlet of the coal-fired boiler 1 .

The flue gas outlet of the sludge separation device 9 is connected to the hot end inlet of the condenser 10 ; the hot end outlet of the condenser 10 is connected to the flue gas inlet of the mixing device 11 .

The cold end of the condenser 10 is connected to an external circulating water device.

The bottom of the condenser 10 is provided with a waste water outlet, and the waste water outlet is connected with a waste water pit 14 .

The flue gas outlet of the mixing device 11 is connected to the flue gas outlet of the air preheater 2 .

A drying induced draft fan 12 is arranged between the flue gas outlet of the mixing device 11 and the coal-fired boiler 1 .

The push-type transmission device is a Jiaolong pusher 5 or a plunger pump system.

The stirring type flue gas dryer 8 adopts the type of dispersing and stirring to strengthen the direct heat exchange between flue gas and wet sludge.

The sludge separation device 9 is a cyclone separation device; the difference between the centrifugal force of the particles and the gravity is used to separate the sludge.

The sludge outlet at the bottom of the sludge separation device 9 is provided with an air lock device.

The condenser 10 is a shell and tube heat exchanger structure.

Due to the negative pressure operation of coal-fired power station boilers, flue gas extraction and transportation need to add drying induced draft fan as a power source before normal operation. The odor from factories and other places shall be managed by process deodorization.

The work flow of this device is as follows:

The flue gas entering the air preheater 2 from the tail flue of the coal-fired boiler 1 becomes medium and high temperature flue gas after passing through the residual heat, and then enters the flue dust separator 3 for separation. The wet sludge transported by the Jiaolong pusher 5 is mixed and sent to the stirring sludge dryer 8 for drying. The dried sludge enters the sludge separation device 9 through the discharge port 7 for separation. Afterwards, the sludge is sent to the coal-fired boiler 1 for combustion through the conveying fan 13 or sent to the boiler pulverizer for grinding and then mixed combustion; the flue gas separated by the sludge separation device is sent to the condenser 10 through the top outlet, The flue gas entering the condenser 10 is cooled by circulating water, and a large amount of water vapor can be removed from the flue gas after cooling.

The cooled flue gas and the medium-high temperature flue gas separated by the soot separator 3 enter the mixing device 11 for mixing, and then send to the tail flue of the coal-fired boiler 1, that is, the outlet of the air preheater and the front end of the dust removal system; avoid water removal The subsequent flue gas temperature is too low, which affects the normal operation of the subsequent system.

The temperature of the flue gas at the flue gas inlet of the air preheater 2 is greater than or equal to 300°C.

Claims (8)

1. The recyclable integrated wastewater treatment system suitable for the coal-fired power plant is characterized by comprising an air preheater (2), a smoke dust separator (3), a stirring type flue gas dryer (8), a sludge separation device (9), a condenser (10) and a drying induced draft fan (12), wherein a flue gas inlet of the air preheater (2) is connected with a flue gas outlet of a coal-fired boiler (1); a flue gas outlet of the air preheater (2) is connected with an inlet of a smoke dust separator (3), a sludge outlet of the smoke dust separator (3) is connected with an inlet of a stirring type flue gas dryer (8), a dry sludge outlet of the stirring type flue gas dryer (8) is connected with an inlet of a sludge separation device (9), and a sludge outlet of the sludge separation device (9) is connected with a feed inlet of the coal-fired boiler (1); a flue gas outlet of the sludge separation device (9) is connected with a hot end inlet of a condenser (10), and a hot end outlet of the condenser (10) is connected with an outlet of the air preheater (2) through a drying induced draft fan (12); and a wet sludge inlet is formed in the stirring type flue gas dryer (8).

2. The integrated wastewater recycling treatment system for coal-fired power plants as recited in claim 1, wherein the wet sludge inlet of the stirring flue gas dryer (8) is connected with a sludge storage bin (4); and a pushing transmission device is arranged between the stirring type flue gas dryer (8) and the sludge storage bin (4).

3. The integrated wastewater recycling treatment system for the coal-fired power plant as recited in claim 1, wherein a mixing device (11) is arranged between the flue gas outlet of the condenser (10) and the drying induced draft fan (12); the mixing device (11) is connected with a smoke outlet of the smoke dust separator (3).

4. The integrated wastewater recycling treatment system for the coal-fired power plant as recited in claim 1, wherein the cold end of the condenser (10) is connected with an external circulating water device; and a waste water outlet is formed in the bottom of the condenser (10).

5. The integrated wastewater treatment system for a coal-fired power plant as set forth in claim 1, wherein a transfer fan (13) is provided between the sludge outlet of the sludge separation unit (9) and the coal-fired boiler (1).

6. An integrated treatment method for recycling wastewater from a coal-fired power plant, which is based on the integrated treatment system for recycling wastewater from a coal-fired power plant of any one of claims 1 to 5, and comprises the following steps:

flue gas entering an air preheater (2) from a tail flue of a coal-fired boiler (1) is subjected to waste heat to form medium-high temperature flue gas, then the medium-high temperature flue gas enters a smoke dust separator (3) for separation, separated dust and wet sludge are mixed and are sent to a stirring type sludge dryer (8) for drying, dried sludge enters a sludge separation device (9) for separation, and the separated sludge is sent to the coal-fired boiler (1) for combustion; the flue gas separated by the sludge separation device (9) is sent to a condenser (10) through a top outlet, and the flue gas entering the condenser (10) is cooled and sent to an outlet of the air preheater (2).

7. The integrated wastewater recycling treatment method for a coal-fired power plant according to claim 6, characterized in that the flue gas temperature of the flue gas inlet of the air preheater (2) is greater than or equal to 300 ℃.

8. The integrated treatment method of claim 6, characterized in that the flue gas cooled by the condenser (10) and the medium-high temperature flue gas separated by the smoke separator (3) enter the mixing device (11) to be mixed and then are sent to the outlet of the air preheater (2).

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