A device for preparing heating steam by using boiler continuous sewage

Abstract

This application provides an apparatus for generating heating steam using boiler blowdown wastewater, comprising: a heat exchange vaporizer having a wastewater inlet, a superheated steam inlet, and a blowdown steam outlet; the wastewater inlet being connected to the surface drain port of the boiler drum via a blowdown pump, and the superheated steam inlet being connected to a superheated steam supply pipeline; a demister having its steam inlet connected to the blowdown steam outlet via a pipeline; a dust collector having its steam inlet connected to the demister's steam outlet via a pipeline, the dust collector comprising several parallel, elongated cyclones, each cyclone having a steam inlet on its side wall, a steam outlet at its top, and a blowdown outlet at its bottom; and a filter having its steam inlet connected to the dust collector's steam outlet, and its steam outlet connected to the heating steam pipeline. This application efficiently filters and purifies the vaporized blowdown steam, achieving a three-stage filtration and purification efficiency of >99% for crystalline salt particles and mist droplets.

Description

Technical Field

[0001] This application belongs to the field of industrial waste heat recovery and utilization, specifically relating to a device for generating heating steam using boiler wastewater. Background Technology

[0002] During the operation of industrial boilers, in order to control the concentration of dissolved salts, alkalinity, and silicates in the boiler water and prevent scaling from affecting boiler thermal efficiency, it is necessary to continuously discharge a portion of high-temperature, high-pressure boiler water from the area with the highest salt and alkali concentration. This reduces the salt content in the boiler water, ensures its quality, and enables the boiler to operate safely and stably for a long period. The blowdown rate of industrial boilers is approximately 1% to 1.5%. The continuous discharge of high-temperature, high-pressure wastewater (taking a 1000t / h coal-fired boiler as an example, the discharge pressure is approximately 18MPa, the discharge temperature is approximately 350℃, and the calorific value of the pollutant is approximately 1770kJ / kg) and the resulting waste heat loss is a significant factor contributing to boiler heat loss.

[0003] Methods for recovering waste heat from boiler continuous blowdown include flash expansion, blowdown heat exchange, or a combination of both. However, existing recovery technologies have failed to achieve intensive resource utilization. Direct use of discharged saline wastewater for heating can easily lead to pipeline corrosion and blockage, and the cost of treating and reusing saline wastewater is high. Utility Model Content

[0004] This application provides a device for generating heating steam using boiler wastewater. The device efficiently filters and purifies the vaporized wastewater to remove impurities. After three-stage filtration and purification, the wastewater has a crystallization salt particle and mist droplet capture efficiency of >99%, which can effectively solve the problems of corrosion and blockage of heating pipelines that are easily caused when generating heating steam from wastewater.

[0005] An apparatus for generating heating steam using boiler continuous wastewater includes a heat exchange vaporizer having a wastewater inlet, a superheated steam inlet, and a continuous wastewater steam outlet. The wastewater inlet is connected to the surface drain port of the boiler drum via a wastewater pump, and the superheated steam inlet is connected to a superheated steam supply pipeline. Also includes: The demister's steam inlet is connected to the continuous steam outlet via a pipeline; The dust collector has a steam inlet connected to the steam outlet of the demister via a pipeline. The dust collector includes several parallel and elongated cyclones. Each cyclone has a steam inlet on its side wall, a steam outlet at its top, and a drain outlet at its bottom. The filter's steam inlet is connected to the dust collector's steam outlet, and the steam outlet is connected to the heating steam pipeline.

[0006] The wastewater from the boiler drum of a thermal power unit is pumped to a heat exchanger vaporizer. After desuperheating and pressure reduction evaporation, and direct contact with superheated steam introduced into the vaporizer, the generated steam mixes with the superheated steam to form continuous exhaust steam, which is discharged from the top of the vaporizer. However, the continuous exhaust steam generated from the evaporation of wastewater on the boiler surface contains a large amount of crystalline salts (sodium salts, silicates, phosphates) and high-concentration salt droplets that have not been completely vaporized. These contaminants, if directly introduced into the heating steam pipeline, can easily cause corrosion and blockage. This application addresses this issue by using a three-stage filtration process to efficiently filter and purify the vaporized continuous exhaust steam, removing impurities and solving the technical challenges in preparing heating steam from boiler wastewater.

[0007] The continuous exhaust steam sequentially enters a demister, a dust collector, and a filter. The demister filters out droplets and crystalline salt particles with a diameter >100μm, the dust collector filters out droplets and crystalline salt particles with a diameter of 30~100μm, and the filter filters out droplets and crystalline salt particles with a particle size of less than 30μm. After three stages of filtration, the continuous exhaust steam can achieve a particulate matter purification efficiency of >99.9%.

[0008] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0009] Optionally, the demister includes at least one demister layer arranged vertically on the continuous steam flow path; the single demister layer includes a porous metal frame and a wire mesh filter layer encapsulated in the porous metal frame; the thickness of the wire mesh filter layer is 5~20cm; the pore size of the wire mesh filter layer is ≤100μm.

[0010] Preferably, the demister has 2 to 3 layers of demister layers arranged along the flow path of the continuous steam.

[0011] Optionally, the demister further includes a demister housing, the outer peripheral edges of the demister layer abutting against the inner wall of the demister housing, and the bottom of the demister housing having a drain port; the steam inlet and steam outlet of the demister housing are located on opposite side walls of the demister housing and separated by the demister layer.

[0012] After the continuous steam enters the demister, it passes vertically through the demister layer. Droplets larger than 100μm and crystalline salt particles in the continuous steam are captured by the demister. The captured crystalline salt particles are washed down by the droplets and discharged from the drain port at the bottom of the shell.

[0013] Optionally, the height of the cyclone is 500~700mm and the diameter is 80~120mm; the steam inlet of the cyclone is a long strip inlet with a height of 50~80mm and a width of 5~15mm.

[0014] Optionally, the dust collector also includes a dust collector housing, which is divided into three independent chambers arranged vertically by upper and lower mounting plates, namely, an exhaust chamber, an inlet chamber, and a sludge discharge chamber, from top to bottom; a plurality of cyclones are installed in an array through the upper and lower mounting plates, with the inlet of each cyclone connected to the inlet chamber, the outlet of each cyclone connected to the exhaust chamber, and the sludge discharge outlet connected to the sludge discharge chamber.

[0015] The dust collector employs several slender cyclones arranged side by side. Steam filtered by the demister enters the inlet chamber of the dust collector and then enters each cyclone. Inside the cyclone, the steam swirls and spirals. Under the action of centrifugal force, particles and fine droplets that cannot be filtered by the demister are captured by the cyclone dust removal unit and move downwards, exiting from the lower drain port. The continuous exhaust steam that completes the dust removal process exits from the top of each cyclone dust removal unit, enters the exhaust chamber, and finally enters the filter. The dust collector of this application can filter out droplets and crystalline salt particles with a diameter of 30~100μm.

[0016] Optionally, the filter includes several filter elements arranged in parallel. Each filter element is a hollow cylindrical filter element with one end open and the other end closed. Several filter elements are installed side by side with their open ends facing downwards, and their open ends serve as the steam outlets of the filter elements.

[0017] Optionally, the filter further includes a filter housing, in which an upper and lower independent steam inlet chamber and a steam outlet chamber are separated by a filter element mounting plate. Several filter elements are installed through the filter element mounting plate, with their cylindrical parts located in the steam inlet chamber and their open ends connected to the steam outlet chamber.

[0018] Optionally, the filter elements are arranged in an array and fixedly installed on the filter element mounting plate.

[0019] Optionally, the filter element is made of a polymer porous material; the pore size of the polymer porous material is <3μm.

[0020] Optionally, the exhaust chamber is provided with a backflushing steam inlet.

[0021] Steam, after being filtered by the dust collector, enters the filter. The steam penetrates the sidewalls of each filter element and enters the hollow cylinder of the filter element. The filtered steam exits from the open end of the filter element. Droplets and crystalline salt particles in the steam that were not captured by the dust collector are intercepted by the filter element. The filter of this application can filter droplets and crystalline salt particles with a particle size of less than 30 μm in steam. After the filter element becomes saturated, it can be regenerated by introducing backflushing steam.

[0022] This application also provides a method for preparing heating steam using boiler continuous wastewater. The method involves using the device to pump the surface continuous wastewater from the boiler drum into a heat exchanger vaporizer via a wastewater pump. The steam generated by the de-cooling and de-pressure evaporation and contact heat exchange evaporation with the superheated steam introduced into the heat exchanger vaporizer is mixed with the superheated steam after heat exchange to form continuous wastewater steam that is discharged from the top of the heat exchanger vaporizer. The continuously discharged steam sequentially enters a demister, a dust collector, and a filter for purification. The demister filters out droplets and crystalline salt particles with a diameter >100μm, the dust collector filters out droplets and crystalline salt particles with a diameter between 30 and 100μm, and the filter filters out droplets and crystalline salt particles with a particle size less than 30μm. The steam filtered by the filter is used as heating steam.

[0023] Optionally, the superheated steam introduced into the heat exchange vaporizer has a pressure of 1.3±0.5MPa and a temperature of 470±10℃. Optionally, the superheated steam can be derived from the exhaust steam of the low-pressure or medium-pressure cylinder of the thermal power unit. Optionally, the pressure of the exhaust steam discharged from the heat exchange vaporizer is 0.8~2MPa, and the temperature is 200~300℃; Optionally, in the filter, the steam velocity at the control section is 2.0~3.8m / s during steam filtration; and the steam velocity at the backflushing section is 5~10m / s during steam backflushing.

[0024] Compared with the prior art, this application has the following beneficial effects: This application performs three-stage purification on the vaporized continuous exhaust steam: a demister filters out droplets and crystalline salt particles with a diameter >100μm, a dust collector filters out droplets and crystalline salt particles with a diameter of 30~100μm, and a filter filters out droplets and crystalline salt particles with a particle size less than 30μm; the steam filtered by the filter is used as heating steam.

[0025] This application performs efficient filtration and purification of the vaporized continuous exhaust steam to remove impurities from the steam. After three-stage filtration and purification, the continuous exhaust steam has a crystallization salt particle and mist droplet capture efficiency of >99%, which can effectively solve the problems of corrosion and blockage of heating pipelines that are easily caused when the continuous exhaust wastewater is used to prepare heating steam. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the device in this application.

[0027] Figure 2 for Figure 1 Enlarged view of the dust collector.

[0028] Figure 3 This is a three-dimensional structural diagram of a dust collector.

[0029] Figure 4 and Figure 5 This is a schematic diagram of the cyclone separator at different angles in a dust collector.

[0030] Figure 6 for Figure 1 A magnified view of the filter.

[0031] Figure 7 This is a schematic diagram of the structure of a single filter element in the filter and a schematic diagram of the steam flow direction during filtration.

[0032] Figure 8 This is a schematic diagram of the steam flow direction during backflushing of a single filter element in a filter.

[0033] Figure 9 This is a process flow diagram of the method described in this application.

[0034] The reference numerals in the figure are as follows: 1. Boiler drum; 2. Sewage pump; 3. Heat exchange vaporizer; 4. Demister; 5. Dust collector; 6. Filter; 41. Demister layer; 42. Demister housing; 51. Dust collector inlet chamber; 52. Dust collector exhaust chamber; 53. Dust collector exhaust chamber; 54. Upper mounting plate; 55. Lower mounting plate; 56. Cyclone (56a. Cyclone inlet; 56b. Cyclone outlet; 56c. Cyclone exhaust outlet); 57. Dust collector shell; 61. Filter inlet chamber; 62. Filter exhaust chamber; 63. Filter element mounting plate; 64. Filter element; 65. Filter housing; h1, height of the cyclone; d, diameter of the cyclone; h2, height of the steam inlet of the cyclone; w, width of the steam inlet of the cyclone. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0037] like Figure 1As shown, an apparatus for generating heating steam using boiler wastewater includes a heat exchange vaporizer 2. The heat exchange vaporizer is used for cooling and depressurizing the wastewater for evaporation and for direct heat exchange evaporation between the wastewater and superheated steam. The heat exchange vaporizer 2 has a wastewater inlet, a superheated steam inlet, and a wastewater steam outlet. The wastewater inlet and the superheated steam inlet are located at different heights on the side wall. The wastewater inlet can be located above the superheated steam inlet. The wastewater inlet is connected to the surface drain port of the boiler drum 1 through a wastewater pump 2. The wastewater is sent into the heat exchange vaporizer and can be distributed by spraying. The superheated steam inlet is connected to a superheated steam supply pipeline to introduce superheated steam into the heat exchange vaporizer. In this embodiment, a three-stage filter is designed downstream of the heat exchange vaporizer, consisting of a demister 4, a dust collector 5, and a filter 6. The steam inlet of the demister 4 is connected to the continuous steam outlet of the heat exchange vaporizer 3 via a pipeline. The steam outlet of the demister 4 is connected to the steam inlet of the dust collector 5 via a pipeline. The steam outlet of the dust collector 5 is connected to the steam inlet of the filter 6 via a pipeline. The steam outlet of the filter 6 is connected to the heating steam pipeline.

[0038] The demister, as a primary filtration device, is used to filter mist droplets and crystalline salt particles larger than 100 μm. In some implementation methods, see [link to relevant documentation]. Figure 1 The demister 4 includes at least one vertically arranged demister layer 41, preferably 2 to 3 layers, arranged sequentially on the flow path of the continuous steam, for continuous and multiple collection of mist droplets and crystalline salt particles in the steam.

[0039] In some embodiments, the single-layer demisting layer includes a porous metal frame and a wire mesh filter layer encapsulated within the porous metal frame; the thickness of the wire mesh filter layer is 5~20cm; the wire mesh filter layer can be formed by stacking or winding multiple layers of metal wire mesh, or by extruding stacked metal wires; the pore size of the wire mesh filter layer is ≤100μm. The demister 4 also includes a demister housing 42. The outer peripheral edges of the demister layer 41 are respectively connected to the top inner wall of the demister housing. The steam inlet and steam outlet of the demister housing are located on opposite side walls of the demister housing and separated by the demister layer 41. The bottom of the demister housing has a drain port, such as... Figure 1 In the orientation shown, steam enters from the left side of the demister and exits from the right side. The steam inside the demister flows sequentially through multiple demister layers 41. After entering the demister, the continuous exhaust steam passes vertically through the demister layers. Droplets larger than 100μm and crystalline salt particles in the continuous exhaust steam are captured by the demister. The captured crystalline salt particles are washed down by the droplets and discharged from the drain port at the bottom of the shell.

[0040] The dust collector serves as a secondary filtration mechanism for continuous steam discharge; see [link / reference]. Figures 2-5It includes several parallel, elongated cyclone tubes 56. Each cyclone tube has a steam inlet 56a on its side wall, a steam outlet 56b at its top, and a conical opening at its bottom serving as a drain outlet 56c. See also some embodiments. Figure 4 and Figure 5 The height h1 of the slender cyclone is 500~700mm and the diameter d is 80~120mm; the steam inlet 56a of the cyclone is a long strip inlet with a height h2 of 50~80mm and a width w of 5~15mm.

[0041] The dust collector also includes a dust collector housing 57, as described in some embodiments, see [link to relevant documentation]. Figure 2 and Figure 3 The dust collector housing 57 is divided into three independent chambers arranged vertically by an upper mounting plate 54 and a lower mounting plate 55. From top to bottom, these are the dust collector exhaust chamber 53, the dust collector inlet chamber 51, and the dust collector drain chamber 52. The dust collector's steam inlet is located on the side wall of the inlet chamber, and the dust collector's steam outlet is located at the top of the exhaust chamber. The dust collector has a drain outlet at the bottom. Several cyclones 56 are vertically connected to the upper and lower mounting plates and are fixedly installed on the upper and lower mounting plates in a rectangular array. The steam inlet of each cyclone 56 is connected to the middle inlet chamber, the steam outlet of each cyclone is connected to the upper exhaust chamber, and the drain outlet of each cyclone is connected to the lower drain chamber. The connection between each cyclone and the upper and lower mounting plates is sealed and fixed. The steam inlets of all cyclones are arranged facing the side where the dust collector's steam inlet is located.

[0042] Steam filtered by the demister enters the inlet chamber 51 of the dust collector, and then enters each cyclone 56. Inside the cyclone 56, the steam swirls and spirals. Under the action of centrifugal force, particles and fine droplets that cannot be filtered by the demister are captured by the cyclone dust removal unit and move downwards. They are then discharged from the cyclone outlet to the discharge chamber. The continuous steam that has completed the dust removal is discharged from the top of each cyclone dust removal unit, enters the exhaust chamber, and is discharged from the steam outlet at the top into the filter. The dust collector uses several slender cyclone 56 arranged side by side, which can filter out droplets and crystalline salt particles with a diameter of 30~100μm.

[0043] The filter serves as a three-stage filtration device for continuous steam exhaust; see [link / reference]. Figures 6-8 The filter 6 includes several filter elements 64 arranged in parallel. In some embodiments, the filter element is a hollow cylindrical filter element with one end open and the other end closed. Several filter elements are installed side by side with their open ends facing down, and the open end of the filter element serves as the steam outlet of the filter element.

[0044] The filter 6 also includes a filter housing 65, which is divided by a filter element mounting plate 63 into an upper filter inlet chamber 61 and a lower filter outlet chamber 62, which are independent of each other. The steam inlet of the filter is located on the side wall of the filter inlet chamber, and the steam outlet of the filter is located on the side wall of the filter outlet chamber. Several filter elements 64 are arranged in an array and installed through the filter element mounting plate 63. They are fixedly installed near their open ends to the filter element mounting plate, and the connection is sealed. The cylindrical part of the filter element is located in the filter inlet chamber 61, and the open end of the filter element extends to the bottom of the filter element mounting plate 63 and communicates with the filter outlet chamber 62.

[0045] The steam, after being filtered by the dust collector, enters the filter. The steam penetrates the side walls of each filter element and enters the hollow cylinder of the filter element. The filtered steam exits from the open end of the filter element. Miscellaneous droplets and crystalline salt particles in the steam that were not captured by the dust collector are intercepted by the filter element. The steam flow direction during filtration is as follows: Figure 7 As shown.

[0046] In some embodiments, the filter element may be made of a polymer porous material with a pore size of <3μm.

[0047] In some implementations, the filter exhaust chamber is also provided with a backwash steam inlet. After the filter element is saturated, it is regenerated by introducing backwash steam. During backwashing, the steam flow direction is as follows: Figure 8 As shown.

[0048] The process flow for preparing heating steam using the above-mentioned apparatus is as follows: Figure 9 As shown: The concentrated brine (steam-water mixture) on the surface of the boiler drum is pumped into the heat exchange vaporizer via a blowdown pump. Some of the boiler water evaporates due to de-cooling and depressurization, and the steam is discharged from the top of the vaporizer. Some superheated steam is introduced into the vaporization heat exchange device. The introduced superheated steam continues to exchange heat with the unevaporated wastewater to evaporate the wastewater. The steam discharged from the wastewater, the steam evaporated due to de-cooling and depressurization, and the steam generated by the superheated steam from the boiler water mix to form continuous drainage steam, which is discharged from the top of the heat exchange vaporizer. The continuous drainage steam contains a certain concentration of unevaporated concentrated liquid droplets and crystalline salt particles.

[0049] The vaporized steam sequentially enters a demister, a dust collector, and a filter for purification and filtration. The demister filters out droplets and crystalline salt particles with a diameter >100μm, the dust collector filters out droplets and crystalline salt particles with a diameter between 30 and 100μm, and the filter filters out droplets and crystalline salt particles with a particle size less than 30μm. The steam filtered by the filter is used as heating steam to realize the recovery and utilization of waste heat from the continuous grate boiler water.

[0050] The pressure of the superheated steam introduced into the heat exchange vaporizer is 1.3±0.5MPa and the temperature is 470±10℃; the superheated steam can come from the exhaust steam of the low-pressure or medium-pressure cylinder of the thermal power unit.

[0051] The pressure of the steam entering the demister is 0.8~2MPa, and the temperature is 200~300℃.

[0052] In the filter, the cross-sectional flow velocity of steam during steam filtration is 2.0~3.8m / s, and the cross-sectional flow velocity of steam during backflushing is 5~10m / s'.

[0053] The continuous exhaust steam is filtered through a three-stage process of demister, dust collector and filter before being used as heating steam, achieving a particulate matter purification efficiency of >99.9%.

[0054] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An apparatus for generating heating steam using boiler continuous wastewater, comprising a heat exchange vaporizer having a wastewater inlet, a superheated steam inlet and a continuous wastewater steam outlet, wherein the wastewater inlet is connected to a surface drain port of the boiler drum via a wastewater pump, and the superheated steam inlet is connected to a superheated steam supply pipeline. Its features are, Also includes: The demister's steam inlet is connected to the continuous steam outlet via a pipeline; The dust collector has a steam inlet connected to the steam outlet of the demister via a pipeline. The dust collector includes several parallel and elongated cyclones. Each cyclone has a steam inlet on its side wall, a steam outlet at its top, and a drain outlet at its bottom. The filter's steam inlet is connected to the dust collector's steam outlet, and the steam outlet is connected to the heating steam pipeline.

2. The apparatus according to claim 1, characterized in that, The demister includes at least one demister layer arranged vertically on the continuous steam flow path; each demister layer includes a porous metal frame and a wire mesh filter layer encapsulated within the porous metal frame; the thickness of the wire mesh filter layer is 5~20cm; the pore size of the wire mesh filter layer is ≤100μm.

3. The apparatus according to claim 2, characterized in that, The demister also includes a demister housing, the outer peripheral edges of the demister layer are respectively connected to the inner wall of the demister housing, and the bottom of the demister housing has a drain port; the steam inlet and steam outlet of the demister housing are respectively located on opposite side walls of the demister housing and separated by the demister layer.

4. The apparatus according to claim 1, characterized in that, The dust collector also includes a dust collector housing, which is divided into three independent chambers arranged vertically by upper and lower mounting plates. From top to bottom, these chambers are an exhaust chamber, an inlet chamber, and a sludge discharge chamber. Several cyclones are installed in an array, passing through the upper and lower mounting plates. The inlet of each cyclone is connected to the inlet chamber, the outlet is connected to the exhaust chamber, and the sludge discharge outlet is connected to the sludge discharge chamber.

5. The apparatus according to claim 1, characterized in that, The height of the cyclone is 500~700mm and the diameter is 80~120mm; the steam inlet of the cyclone is a long strip inlet with a height of 50~80mm and a width of 5~15mm.

6. The apparatus according to claim 1, characterized in that, The filter includes several filter elements arranged in parallel. Each filter element is a hollow cylindrical filter element with one end open and the other end closed. Several filter elements are installed side by side with their open ends facing downwards, and their open ends serve as the steam outlets of the filter elements.

7. The apparatus according to claim 6, characterized in that, The filter also includes a filter housing, which is divided into an upper and lower independent steam inlet chamber and a steam outlet chamber by a filter element mounting plate. Several filter elements are installed through the filter element mounting plate, with their cylindrical parts located in the steam inlet chamber and their open ends connected to the steam outlet chamber.

8. The apparatus according to claim 6, characterized in that, The filter element is made of a polymer porous material; the pore size of the polymer porous material is <3μm.

Images