Low-temperature corrosion prevention device for yellow phosphorus tail gas boiler

Abstract

The utility model provides a yellow phosphorus tail gas boiler low-temperature corrosion prevention device which comprises a powder bin, the powder bin is connected with a pneumatic conveying pipeline through a pneumatic conveying device, the tail end of the pneumatic conveying pipeline is provided with a powder spraying inlet, and the powder spraying inlet is located in a boiler tail flue. A first soot blower, a first-stage economizer, a second soot blower, a second-stage economizer, a third soot blower and an air pre-heater are sequentially arranged below the powder injection inlet; and the tail end of the boiler tail flue is connected with a bag-type dust According to the utility model, the Alloy625 nickel-based alloy or silicon carbide is completely covered and overlaid on the outer walls of the economizer and the air pre-heater heat exchange tube, so that the economizer and the air pre-heater heat exchange tube at a low-temperature section are prevented from being corroded and perforated; meanwhile, a powder spraying device is additionally arranged, alkaline powder is sprayed into the tail flue, acidic substances and moisture in the flue gas are absorbed, and corrosion of components in the flue is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to tail gas treatment field, concretely is a kind of yellow phosphorus tail gas boiler low-temperature corrosion prevention device. BACKGROUND

[0002] In yellow phosphorus production, yellow phosphorus tail gas containing CO is by-produced, about 2500-3000m³ yellow phosphorus tail gas is by-produced for each ton of yellow phosphorus, and the content of CO in yellow phosphorus tail gas is generally above 80%. Yellow phosphorus tail gas is a high-quality gas fuel (containing heat value is about 10659kJ / Nm³), compared with producer gas (air coal gas heat value 4500kJ / Nm³, mixed coal gas heat value 5500-6000kJ / Nm³, water coal gas heat value 10450kJ / Nm³), its heat value is much higher than air coal gas and mixed coal gas, equivalent to water coal gas and oxygen-enriched coal gas. Yellow phosphorus tail gas is used as heat source to generate power by waste heat, and yellow phosphorus tail gas can be effectively utilized, and yellow phosphorus tail gas waste heat power generation process has been operated for many years in yellow phosphorus industry.

[0003] Because yellow phosphorus tail gas contains many impurities (sulfur, phosphorus, fluorine, etc.), these impurities will form acidic substances after being burned in the boiler, and form condensate acid in the low-temperature section of the boiler tail flue, which causes corrosion to the boiler accessories, especially causes serious corrosion to the economizer and air preheater in the boiler tail flue, reduces the service life of the economizer and air preheater, and increases the operation safety risk of the boiler.

[0004] In view of the corrosion problem of the tail flue of the yellow phosphorus tail gas waste heat boiler, the utility model provides a yellow phosphorus tail gas boiler low-temperature corrosion prevention device to solve the problem. UTILITY MODEL CONTENTS

[0005] The utility model provides a kind of yellow phosphorus tail gas boiler low-temperature corrosion prevention device, including powder bin, powder bin is connected by pneumatic conveying device pneumatic conveying pipeline, and the end of pneumatic conveying pipeline is equipped with powder injection port, and powder injection port is located in the inside of boiler tail flue;Powder injection port is equipped with ash blower one, primary economizer, ash blower two, secondary economizer, ash blower three and air preheater in sequence below;Boiler tail flue end is connected bag-type dust collector.

[0006] The primary economizer, the secondary economizer and the air preheater are located in the low-temperature section below 450 DEG C of the boiler tail flue;The outer wall of the primary economizer, the secondary economizer and the air preheater is fully covered with Alloy625 nickel-based alloy or silicon carbide by surfacing welding;The inner wall of the boiler tail flue is fully covered with Alloy625 nickel-based alloy by surfacing welding.

[0007] The lower side of the bag-type dust collector is equipped with screw conveyor, and the lower side of the screw conveyor is equipped with metering scale two.

[0008] The powder bin is connected with metering scale one.

[0009] The first, second and third soot blowers are ultrasonic soot blowers or shock wave soot blowers.

[0010] The utility model has the advantages that:

[0011] 1. Alloy 625 nickel-based alloy or silicon carbide is fully covered and stacked on the outer wall of the heat exchange tube of the economizer and the air preheater in the low-temperature section of the boiler tail flue below 450 DEG C, which protects the economizer and the air preheater in the low-temperature section of the boiler tail flue by using the corrosion resistance of Alloy 625 nickel-based alloy or silicon carbide, and does not affect the heat exchange efficiency of the boiler.

[0012] 2. A powder material injection port is arranged in the low-temperature section of the boiler tail flue, alkaline powder material is injected, a soot blower is arranged in the tail flue to blow, and a bag-type dust collector is arranged behind the tail flue to collect the powder material in the injection system. The alkalinity and water absorption of the alkaline powder material absorb the water and acidic substances in the flue gas of the boiler, thereby effectively protecting the economizer and the air preheater in the low-temperature section of the boiler tail flue. Meanwhile, the soot blowing system can avoid powder blockage between the heat exchange tubes of the economizer and the air preheater, increase the wind resistance of the tail flue, and further affect the normal operation of the boiler.

[0013] 3. The alkaline material is transported into the low-temperature section of the tail flue through a pneumatic conveying system, a metering scale one is arranged to measure the injection amount of the alkaline powder, a bag-type dust collector is arranged behind the tail flue to collect the reacted material, and a metering scale two is arranged to measure the recovery amount. The difference between the feeding amount and the discharging amount can be used to determine whether the system is accumulated with material. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The device schematic view of the application.

[0015] Marked in the figure: powder bin 1, metering scale one 2, pneumatic conveying device 3, pneumatic conveying pipeline 4, powder injection port 4-1, soot blower one 5-1, soot blower two 5-2, soot blower three 5-3, primary economizer 6-1, secondary economizer 6-2, air preheater 7, bag-type dust collector 8, screw conveyor 9, metering scale two 10, and boiler tail flue 11. DETAILED DESCRIPTION

[0016] The implementation scheme of the utility model will be described in detail in combination with the embodiments below, and the following embodiments are only used to illustrate the utility model and should not be regarded as limiting the scope of the utility model.

[0017] Embodiment 1

[0018] The device for preventing low-temperature corrosion of a yellow phosphorus tail gas boiler comprises a powder bin 1, the powder bin 1 is connected with a pneumatic conveying pipeline 4 through a pneumatic conveying device 3, the pneumatic conveying pipeline 4 is provided with a powder injection port 4-1 at the tail end, and the powder injection port 4-1 is located in the inside of a boiler tail flue 11; a soot blower 5-1, a primary economizer 6-1, a soot blower 5-2, a secondary economizer 6-2, a soot blower 5-3 and an air preheater 7 are sequentially arranged below the powder injection port 4-1; and the boiler tail flue 11 is connected with a bag-type dust collector 8 at the tail end.

[0019] The primary economizer 6-1, the secondary economizer 6-2 and the air preheater 7 are located in a low-temperature section below 450 DEG C of the boiler tail flue 11; the outer walls of the primary economizer 6-1, the secondary economizer 6-2 and the air preheater 7 are entirely covered with a cladding of Alloy 625 nickel-based alloy or silicon carbide; and the inner wall of the boiler tail flue 11 is entirely covered with a cladding of Alloy 625 nickel-based alloy.

[0020] A spiral conveyor 9 is arranged below the bag-type dust collector 8, and a metering scale 10 is arranged below the spiral conveyor 9.

[0021] The powder bin 1 is connected with the metering scale 2.

[0022] The soot blowers 5-1, 5-2 and 5-3 are ultrasonic soot blowers or shock wave soot blowers.

[0023] Embodiment 2

[0024] After the powder in the powder bin 1 is metered by the metering scale 2, the powder enters the pneumatic conveying device 3, passes through the pneumatic conveying pipeline 4, is conveyed into the front end of the primary economizer 6-1 inside the boiler tail flue 11, is sprayed out through the powder injection port 4-1, covers and protects the outer walls of the heat exchange pipes of the primary economizer 6-1 and the secondary economizer 6-2 and the outer walls of the heat exchange pipes of the air preheater 7, and is mixed with the flue gas; in order to avoid the powder from being blocked between the heat exchange pipes of the primary economizer 6-1, the secondary economizer 6-2 and the air preheater 7, the soot blowers 5-1, 5-2 and 5-3 are regularly used for blowing and cleaning, the powder is mixed with and absorbs the acidic substances and moisture in the boiler flue gas, enters the bag-type dust collector 8 for separation, the powder is conveyed and bagged through the spiral conveyor 9, is weighed through the metering scale 10, and the flue gas enters the subsequent section. All operations of the system are controlled on a DCS system, the feeding amount can be adjusted by observing the dryness and moisture of the discharged material and the pressure difference before and after the boiler tail flue, and whether the system is blocked can be judged by the difference between the readings of the metering scale 2 and the metering scale 10.

Claims

1. A low-temperature corrosion prevention device for a yellow phosphorus tail gas boiler, characterized in that, It comprises a powder bin (1), the powder bin (1) is connected with pneumatic conveying device (3) pneumatic conveying pipeline (4), the end of pneumatic conveying pipeline (4) is provided with powder injection port (4-1), powder injection port (4-1) is located in the boiler tail flue (11) inside;Powder injection port (4-1) below are provided with soot blower one (5-1), first stage economizer (6-1), soot blower two (5-2), second stage economizer (6-2), soot blower three (5-3) and air preheater (7);The end of boiler tail flue (11) is connected with bag filter (8).

2. The low-temperature corrosion prevention device for a yellow phosphorus tail gas boiler according to claim 1, characterized in that, The first stage economizer (6-1), second stage economizer (6-2) and air preheater (7) are located in the low temperature section below 450 DEG C of boiler tail flue (11);The outer wall of first stage economizer (6-1), second stage economizer (6-2) and air preheater (7) is fully covered with Alloy625 nickel-based alloy or silicon carbide;The inner wall of boiler tail flue (11) is fully covered with Alloy625 nickel-based alloy.

3. The low-temperature corrosion prevention device for yellow phosphorus tail gas boiler according to claim 1, characterized in that, The lower side of bag filter (8) is provided with screw conveyor (9), and the lower side of screw conveyor (9) is provided with metering scale two (10).

4. The low-temperature corrosion prevention device for a yellow phosphorus tail gas boiler according to claim 1, characterized in that, The powder bin (1) is connected with metering scale one (2).

5. The low-temperature corrosion prevention device for a yellow phosphorus tail gas boiler according to claim 1, characterized in that, The soot blower one (5-1), soot blower two (5-2) and soot blower three (5-3) are ultrasonic soot blower or shock wave soot blower.

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