CN105423268A - Three-way power station boiler suitable for 700 DEG C steam parameter - Google Patents

Abstract

The invention discloses a three-channel power plant boiler suitable for steam parameters at 700°C, which includes a water supply pipeline, a horizontal furnace, a main steam pipeline and a reheat steam pipeline. It consists of a heat exchange channel and a tail channel. A number of burners are arranged on the side wall of the combustion channel, and the combustion channel is horizontally distributed; a panel superheater, a high-temperature superheater, a high-temperature reheater, and a medium-temperature reheater are installed in the main heat exchange channel. Heater, flue gas baffle, low-temperature reheater, low-temperature superheater, secondary economizer and flue separation screen; the tail channel is equipped with a primary economizer, SCR denitrification device and air preheater, and the tail The channel is composed of connected horizontal flue and vertical flue, wherein the horizontal flue is connected with the main heat exchange channel. In the present invention, the amount of high-temperature alloy material is low, the cycle thermal efficiency of the unit is high, the cost of the unit is low, and the safety and stability are high.

Description

A Three-channel Utility Boiler Applicable to 700℃ Steam Parameters

technical field

The invention belongs to the field of thermal power generation and relates to a three-channel power plant boiler suitable for steam parameters at 700°C.

Background technique

With the continuous rise of energy prices around the world, countries have stricter requirements on energy conservation and consumption reduction. How to tap the potential of energy conservation and reduce the production and operation costs of enterprises has become an important issue of common concern to every enterprise. For power generation companies, the higher the cycle efficiency of the system, the lower the energy consumption per unit of power generation, and the lower the corresponding energy consumption and pollutant emissions. Increasing the steam pressure and temperature level has always been the most effective means for power systems to improve unit cycle efficiency, which is also the source of power for the development of 700°C ultra-supercritical power plant units worldwide.

Supercritical and ultra-supercritical units are constantly developing at home and abroad. The United States and the former Soviet Union are the countries with the largest number of supercritical units in the world. The technology of ultra-supercritical units in Denmark, Japan and Germany is very mature. The ultra-supercritical technology of units of 1000MW and above in my country is also developing rapidly. The steam parameters of the ultra-supercritical double-reheat units currently under construction have reached 620°C and the pressure has reached above 30MPa, reaching the international advanced level. With the continuous development of high-strength material technology, the unit with 720°C high temperature and 31MPa high pressure parameters has become a reality. At present, countries such as the United States, Japan, Europe, and China are vigorously carrying out research and development of 700°C ultra-supercritical technology.

The bottleneck in the research and development process of the 700°C power plant boiler system mainly lies in the characteristics of high-temperature materials. At present, most of the commonly recognized high-temperature usable materials are alloy materials, among which nickel-based alloys have better performance. After the steam temperature increases, the working environment of high-temperature metal materials will deteriorate significantly, which will easily cause material failure; at the same time, the engineering cost of high-temperature alloy materials is quite expensive. If they are used in large quantities, the static investment of the unit will be greatly increased, and the efficiency of the unit will be improved. The positive impact is substantially reduced. Therefore, reducing the amount of superalloy materials is a key factor in the implementation of unit engineering. In the conventional boiler design, the four major pipelines of the boiler are relatively long, and a large amount of expensive high-temperature alloy materials are required, which has become a key factor restricting the design of 700 ℃ power plant boilers. At the same time, in the conventionally designed boiler system, the furnace is arranged vertically, the high-temperature heating surface is arranged in the tail flue, and the elevation of the outlet of the heating surface is high. How to adopt effective technical measures to reduce the consumption of high-temperature alloy materials in the four major pipes of the boiler , reduce the cost of the unit, and improve the safety and stability of the unit operation have become important issues to be solved in the industry.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide a three-channel utility boiler suitable for steam parameters at 700°C. Lower, higher security and stability.

In order to achieve the above purpose, the three-channel power plant boiler suitable for steam parameters at 700°C according to the present invention includes a water supply pipeline, a horizontal furnace, a main steam pipeline and a reheat steam pipeline. Channel, main heat exchange channel and tail channel, there are several burners on the side wall of the combustion channel, and the combustion channel is horizontally distributed; the main heat exchange channel is equipped with a panel superheater, a high temperature superheater, and a high temperature reheater , medium-temperature reheater, flue gas baffle, low-temperature reheater, low-temperature superheater, secondary economizer and flue separation screen; the tail channel is equipped with a primary economizer, SCR denitrification device and air preheating The tail channel is composed of connected horizontal flue and vertical flue, wherein the horizontal flue is connected with the main heat exchange channel;

The panel superheater, high temperature superheater, high temperature reheater and medium temperature reheater are arranged sequentially from bottom to top. The flue separation screen is located above the medium temperature reheater. It is the front flue and the rear flue, in which the low-temperature superheater and the secondary economizer are distributed in the rear flue from bottom to top, the low-temperature reheater is located in the front flue, and the flue gas baffle is located between the low-temperature reheater and the rear flue. Above the secondary economizer;

The primary economizer is located in the transverse channel of the tail flue, and the SCR denitrification device and air preheater are installed in the vertical flue of the tail flue in sequence from top to bottom;

The water supply pipeline is connected to the inlet header of the water-cooled wall at the end of the furnace through the first-level economizer and the second-level economizer in turn, and the inlet header of the water-cooled wall at the end of the furnace is connected to the water-cooled wall of the furnace. The water wall of the furnace, the low-temperature superheater, the panel superheater and the high-temperature superheater are connected with the high-pressure cylinder system in the steam turbine in the power station, and the reheat steam pipeline passes through the low-temperature reheater, the medium-temperature reheater and the high-temperature reheater in turn. The intermediate pressure cylinder systems of the steam turbines in the power station are connected.

A cold ash hopper is provided at the bottom of the combustion channel.

A flame angle is provided on the wall surface of the end of the combustion channel that communicates with the main heat exchange channel.

Each burner is arranged on the left and right side walls of the combustion channel.

The main heat exchange channels are distributed vertically.

The heating surface in the main heat exchange channel is arranged horizontally.

The present invention has the following beneficial effects:

According to the present invention, the combustion channels in the three-channel utility boiler suitable for 700°C steam parameters are distributed horizontally. The furnace is a horizontal furnace, which reduces the elevation of the furnace outlet. The high-temperature superheater and high-temperature reheater are arranged near the smokestack of the furnace outlet. , The elevation of the high temperature superheater and high temperature reheater is also greatly reduced, thereby reducing the amount of superalloy materials used. In addition, the high-temperature superheater and high-temperature reheater are arranged in the high-temperature flue gas area of the furnace exit chimney, thereby increasing heat transfer temperature and pressure, strengthening steam heat absorption, effectively reducing the amount of high-temperature alloy materials, reducing the cost of the unit, and improving Unit safety and stability. At the same time, the boiler feed water passes through the primary economizer, the secondary economizer, the header at the end of the furnace, the water wall of the furnace, the steam-water separator, the low-temperature superheater, the panel superheater and the high-temperature superheater to form main steam. Then it enters the high-pressure cylinder system of the steam turbine to do work. At the same time, the reheated steam enters the medium-pressure cylinder system of the steam turbine to do work after passing through the low-temperature reheater, medium-temperature reheater and high-temperature reheater, thereby effectively improving the unit’s performance. cycle thermal efficiency. According to the present invention, the main steam temperature adjustment of the three-channel power plant boiler suitable for 700°C steam parameters adopts the coal-water ratio + water spray temperature reduction adjustment method, and the reheat steam temperature adopts the flue gas baffle + water spray temperature reduction adjustment method, which has the advantages of: It has the advantages of wide steam temperature adjustment range, small inertia, good sensitivity and little influence on the cycle thermal efficiency of the power station.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Among them, 1 is the burner, 2 is the cold ash hopper, 3 is the furnace, 4 is the flame angle, 5 is the SCR denitrification device, 6 is the panel superheater, 7 is the high temperature superheater, 8 is the high temperature reheater, 9 is a medium temperature reheater, 10 is a flue gas baffle, 11 is a low temperature reheater, 12 is a low temperature superheater, 13 is a secondary economizer, 14 is a flue separation screen, 15 is an air preheater, and 16 is a Level 1 economizer.

detailed description

The present invention is described in further detail below in conjunction with accompanying drawing:

Referring to Fig. 1, the three-channel utility boiler suitable for 700°C steam parameters according to the present invention includes a water supply pipeline, a horizontal furnace 3, a main steam pipeline and a reheat steam pipeline. Channel, the main heat exchange channel and the tail channel, the side wall of the combustion channel is provided with a number of burners 1, the combustion channel is horizontally distributed; the main heat exchange channel is equipped with a panel superheater 6, a high temperature superheater 7, a high temperature Reheater 8, medium temperature reheater 9, flue gas baffle 10, low temperature reheater 11, low temperature superheater 12, secondary economizer 13 and flue separation screen 14; Coal heater 16, SCR denitrification device 5 and air preheater 15, the tail channel is composed of connected horizontal flue and vertical flue, wherein the horizontal flue is connected with the main heat exchange channel; the panel superheater 6, The high-temperature superheater 7, the high-temperature reheater 8 and the medium-temperature reheater 9 are distributed sequentially from bottom to top, and the flue partition screen 14 is located above the medium-temperature reheater 9, and the flue partition screen 14 divides the upper part of the main heat exchange channel It is divided into the front flue and the rear flue, wherein the low-temperature superheater 12 and the secondary economizer 13 are distributed in the rear flue from bottom to top, the low-temperature reheater 11 is located in the front flue, and the flue gas baffle 10 is located in the Above the low-temperature reheater 11 and the secondary economizer 13; the primary economizer 16 is located in the transverse passage of the tail flue, and the SCR denitrification device 5 and the air preheater 15 are arranged in sequence from top to bottom in the tail flue In the vertical flue; the water supply pipe is connected to the water-cooled wall inlet header at the end of the furnace 3 through the first-level economizer 16 and the second-level economizer 13 in turn, and the water-cooled wall inlet header at the end of the furnace 3 is connected to the inlet header of the furnace 3 The water wall is connected, the main steam pipeline is connected to the high pressure cylinder system in the steam turbine in the power station through the water wall of the furnace 3, the low temperature superheater 12, the panel superheater 6 and the high temperature superheater 7 in sequence, and the reheat steam pipeline is connected through the low temperature The reheater 11 , the medium temperature reheater 9 and the high temperature reheater 8 are connected with the medium pressure cylinder system of the steam turbine in the power station.

It should be noted that a cold ash hopper 2 is provided at the bottom of the combustion passage, and a flame bending angle 4 is provided on the wall surface of the end of the combustion passage communicating with the main heat exchange passage, through which the high temperature flue gas can be avoided. A flue gas corridor is formed at the junction of the combustion channel and the main heat exchange channel; each burner 1 is arranged on the left and right side walls of the combustion channel; the main heat exchange channel is vertically distributed.

The heating surface in the main heat exchange channel adopts the horizontal layout of the tower furnace, which is conducive to the drainage of the heating surface and the timely discharge of the oxide skin in the tube after it falls off, so as to effectively prevent the tube explosion caused by the blockage of the oxide scale in the tube.

Concrete work process of the present invention is:

The high-temperature flue gas generated by the burner 1 circulates horizontally in the combustion channel, then enters the main heat exchange channel, and is divided into two paths by the flue partition screen 14 in the main heat exchange channel, one of which enters the front flue, The other way enters the rear flue, the flue gas in the front flue and the flue gas in the rear flue merge and then enter the tail flue, then enter the SCR denitrification device and enter the air preheater 15 after denitrification treatment, and in the air The air is preheated in the preheater 15; the flue gas flow in the front flue and the rear flue is regulated by the flue gas baffle 10, so as to realize the adjustment of the reheated steam temperature under low load conditions.

At the same time, the boiler feed water enters the water supply pipeline, the first-level economizer 16 and the second-level economizer 13 in turn, and then converges in the water-cooled wall inlet header at the end of the furnace 3, and the water in the water-cooled wall inlet header at the end of the furnace 3 As the working medium, it passes through the water-cooled wall of the furnace 3, the low-temperature superheater 12, the panel superheater 6 and the high-temperature superheater 7 to form main steam, and then enters the high-pressure cylinder system in the steam turbine, and the reheat steam passes through the reheat steam pipeline in turn. , low-temperature reheater 11, medium-temperature reheater 9 and high-temperature reheater 8 enter the medium-pressure cylinder system of the steam turbine.

Claims (6)

1. A three-channel utility boiler suitable for steam parameters at 700°C, characterized in that it includes a water supply pipe, a furnace (3), a main steam pipe and a reheat steam pipe, the furnace (3) is a horizontal furnace, and the boiler along the smoke The air flow direction is composed of combustion channels, main heat exchange channels and tail channels connected in sequence. Several burners (1) are arranged on the side walls of the combustion channels, and the combustion channels are horizontally distributed; screens are arranged in the main heat exchange channels. Type superheater (6), high temperature superheater (7), high temperature reheater (8), medium temperature reheater (9), flue gas baffle (10), low temperature reheater (11), low temperature superheater ( 12), a secondary economizer (13) and a flue separation screen (14); a primary economizer (16), an SCR denitrification device (5) and an air preheater (15) are arranged in the tail passage, The tail channel is composed of connected horizontal flue and vertical flue, wherein the horizontal flue is connected with the main heat exchange channel; The panel superheater (6), high temperature superheater (7), high temperature reheater (8) and medium temperature reheater (9) are arranged sequentially from bottom to top, and the flue separation screen (14) is located in the medium temperature reheater ( 9), the flue separation screen (14) divides the passage on the upper part of the main heat exchange passage into a front flue and a rear flue, wherein the low-temperature superheater (12) and the secondary economizer (13) are from the bottom to the are distributed in the rear flue in turn, the low-temperature reheater (11) is located in the front flue, and the flue gas baffle (10) is located above the low-temperature reheater (11) and the secondary economizer (13); The first-level economizer (16) is located in the transverse channel of the tail flue, and the SCR denitrification device (5) and the air preheater (15) are sequentially installed in the vertical flue of the tail flue from top to bottom; The water supply pipeline is connected to the inlet header of the water-cooled wall at the end of the furnace (3) through the first-level economizer (16) and the second-level economizer (13) in turn, and the inlet header of the water-cooled wall at the end of the furnace (3) is connected to the The water-cooled wall of the furnace (3) is connected, and the main steam pipe passes through the water-cooled wall of the furnace (3), the low-temperature superheater (12), the panel superheater (6) and the high-temperature superheater (7) and the steam turbine in the power station in sequence. The high-pressure cylinder system is connected, and the reheat steam pipeline is connected with the medium-pressure cylinder system of the steam turbine in the power station through the low-temperature reheater (11), the medium-temperature reheater (9) and the high-temperature reheater (8) in sequence. 2. The three-channel utility boiler suitable for steam parameters at 700°C according to claim 1, characterized in that a cold ash hopper (2) is provided at the bottom of the combustion channel. 3. The three-channel utility boiler suitable for steam parameters at 700°C according to claim 1, characterized in that a flame angle (4) is provided on the wall surface of the end of the combustion channel that communicates with the main heat exchange channel. 4. The three-channel utility boiler suitable for steam parameters at 700°C according to claim 1, characterized in that each burner (1) is arranged on the left and right side walls of the combustion channel. 5. The three-channel utility boiler suitable for steam parameters at 700°C according to claim 1, characterized in that the main heat exchange channels are vertically distributed. 6. The three-channel utility boiler suitable for steam parameters at 700°C according to claim 1, wherein the heating surfaces in the main heat exchange channels are arranged horizontally.