Biomass pressurized gasification waste heat recovery boiler
Through the double-layer water-cooled wall structure and vertical radiation heating surface design, the problem of alkali metal ash corrosion in the biomass waste heat recovery boiler is solved, the waste heat recovery efficiency and equipment safety are improved, and investment costs are reduced.
Patent Information
- Application Number
- CN202421191466.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-28
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-05-28
AI Technical Summary
Alkaline metals in biomass waste heat recovery boilers are prone to condense, adhere and settle, resulting in corrosion and heat transfer of furnace pipes, affecting the safe and stable operation of the equipment.
The double-layer water-cooled wall structure and vertical radiation heating surface design are adopted to make the dust-containing crude gas flow parallel to the heating surface of the water-cooled fireplace pipe, and seal it with the inlet water-spraying heat-reducing pipe and refractory filler to reduce the ash area of the furnace pipe.
It improves waste heat recovery efficiency, reduces equipment investment costs, and reduces the corrosion risk caused by alkali metal ash accumulation, ensuring the safe and stable operation of the equipment.
Smart Images
Figure CN223240031U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of biomass pressurized gasification, in particular to a biomass pressurized gasification waste heat recovery boiler. Background Art
[0002] Compared to coal, biomass feedstock offers advantages such as high volatility, good gasification activity, low nitrogen, and low sulfur content. However, it also contains very high levels of potassium, sodium, alkali metals, and chlorine. When the biomass reaction temperature in the gasifier reaches above 800°C, the alkali metals transform into a vapor phase and enter the waste heat recovery system along with the raw synthesis gas. In the waste heat recovery boiler, the raw gas undergoes a cooling process, transitioning from a gaseous state directly to a solid state and condensing on the metal surfaces. Traditional waste heat recovery boilers for coal gasification typically utilize tube-and-tube convection or a combination of radiation and convection. However, due to the high alkali metal content in biomass, alkali metals condense, adhere, and settle on the boiler's heating surfaces during the cooling process. Furthermore, the raw gas contains dust. If the operating temperature of the upstream gasification system fluctuates, resulting in localized low temperatures, the raw gas will also contain tar. The combined effects of alkali metals, dust, and tar can exacerbate the dusting of the boiler's heating surfaces, particularly those with convection configurations. Once low-melting-point alkali metal eutectic deposits form on the heating surfaces of the furnace tubes, the chlorine in the molten deposits reacts with the protective oxide film on the metal surface of the tubes, causing high-temperature corrosion. This phenomenon is particularly noticeable in biomass boilers, especially in the high-temperature superheater. These tube deposits not only corrode the tubes but also affect heat transfer. Preventing the effects of alkali metals on boilers has become a key factor restricting the safe, stable, and long-term operation of biomass gasification systems. Utility Model Content
[0003] The utility model aims to solve the problem that the existing biomass waste recovery boiler is prone to alkali metal dust accumulation and corrosion caused by the dust accumulation. The technical solution adopted is: a biomass pressurized gasification waste heat recovery boiler, comprising: a pressure shell, wherein an inner tube water-cooled wall and an outer tube water-cooled wall are provided in the pressure shell, the inner tube water-cooled wall encloses an inner tube water-cooled wall single-side heating cavity, an annular gap water-cooled wall double-side heating cavity is formed between the outer tube water-cooled wall and the inner tube water-cooled wall, a cooling protection gas cavity is formed between the outer tube water-cooled wall and the inner wall of the pressure shell, an annular convex head is provided in the pressure shell to separate the lower end of the pressure shell cavity into an ash hopper, the ash hopper is connected with the inner tube water-cooled wall single-side heating cavity and the annular gap water-cooled wall double-side heating cavity, a dust-containing high-temperature coal gas inlet is provided at the top of the pressure shell, a low-temperature raw coal gas outlet connected with the annular gap water-cooled wall double-side heating cavity is provided on the side wall of the pressure shell, and a cooling protection gas inlet connected with the cooling protection gas cavity is provided on the pressure shell.
[0004] A further improvement is that multiple groups of inner tube heating tube panels are evenly arranged along the circumference of the inner wall of the inner tube water-cooled wall
[0005] A further improvement is that the inner tube heating tube panel is formed by a plurality of vertically arranged metal tubes arranged along the radial direction of the single-side heating cavity of the inner tube water-cooled wall.
[0006] A further improvement is that an inlet water spray cooling pipe is provided on the portion of the dust-laden high-temperature raw gas inlet extending into the inner cavity of the pressure shell.
[0007] A further improvement is that an annular gap inlet water spray cooling pipe is provided at the bottom of the outer tube water-cooled wall.
[0008] A further improvement is that an inner tube displacement guide frame is provided on the outer wall of the inner tube water-cooled wall.
[0009] A further improvement is that an outer tube displacement guide frame is provided on the outer wall of the outer tube water-cooled wall.
[0010] A further improvement is that a corrugated expansion joint is provided on the outer surface of the conical section at the bottom of the outer tube water-cooled wall.
[0011] A further improvement is that an inner tube packing sealing ring is formed between the top of the inner tube water-cooled wall and the dust-laden high-temperature raw coal gas inlet, and the inner tube packing sealing ring is filled with refractory material.
[0012] A further improvement is that an outer tube packing sealing ring is formed between the top of the inner tube water-cooled wall and the top of the outer tube water-cooled wall, and the outer tube packing sealing ring is filled with refractory material.
[0013] The beneficial effects of the utility model are:
[0014] This biomass pressurized gasification waste heat recovery boiler, designed with a vertical radiant heating surface, ensures that the dust-laden raw gas flows parallel to the heating surface of the water-cooled furnace tubes, minimizing the accumulation of dust on the tube heating surface. The double-layered reflux heating surface not only increases waste heat recovery efficiency but also makes the equipment more compact, reducing investment costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0016] Figure 1 This is a schematic diagram of the structure of the biomass pressurized gasification waste heat recovery boiler of the utility model;
[0017] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure along the AA axis. DETAILED DESCRIPTION
[0018] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.
[0019] In the description of the utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the utility model.
[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of a utility model, "plurality" means two or more, unless otherwise specifically defined.
[0021] In utility models, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in utility models based on specific circumstances.
[0022] Example
[0023] like Figure 1 As shown, the present invention provides a biomass pressurized gasification waste heat recovery boiler, comprising: a pressure shell 10, a single-sided heating chamber 20 of an inner tube water-cooled wall, a double-sided heating chamber 30 of an annular gap water-cooled wall, a cooling protection gas chamber 40, and an ash hopper 50. The biomass pressurized gasification waste heat recovery boiler provided by the present invention utilizes a vertical radiant heating surface to ensure that the dust-laden raw coal gas flows parallel to the heating surface of the water-cooled furnace tubes, minimizing the dust accumulation area on the heating surface of the furnace tubes. The double-layered reflux heating surface structure not only increases waste heat recovery efficiency but also makes the equipment structure more compact, reducing investment costs.
[0024] The pressure shell 10 made of metal includes: an upper head 103, which is preferably elliptical and has a better stress state when under pressure. At the same time, the total height of the equipment is kept as low as possible to reduce the frame height and reduce the equipment manufacturing cost. The dust-containing high-temperature gas inlet 101 and the upper head inspection manhole 102 are attached to the upper head 10. The dust-containing high-temperature gas inlet 101 is cylindrical, and its lower part passes through the reserved hole on the upper head 103 and extends into the pressure shell 10. The contact part with the upper head 103 is preferably welded and fixedly connected. The equipment main flange 104 is connected to the upper head 103 and the furnace shell cylinder 107. The upper head 103 and the furnace shell cylinder 107 are connected at the equipment main flange 104. An annular convex head 112 is provided in the pressure shell 10 to separate the lower end of the pressure shell inner cavity into an ash hopper 50.
[0025] One to four low-temperature crude gas outlets 105 are located near the upper end of the shell 107. This placement facilitates the complete heat recovery path for the high-temperature crude gas, improving the waste heat recovery efficiency of the boiler. Water-cooled wall supports 106 for securing the water-cooled wall are located on the shell 107 at a certain height from the low-temperature crude gas outlets 105. Correspondingly, the outer water-cooled wall is provided with transversely extending legs for overlapping the water-cooled wall supports 106. Furthermore, a displacement guide 108 is provided on the inner wall of the shell 107 to limit the expansion direction of the water-cooled wall. This displacement guide 108 consists of two parts: a groove member fixed to the shell 107, having a transversely extending groove; and a transverse insert fixed to the water-cooled wall. The insert's end is embedded in the groove of the groove member, and the two are interchangeable.
[0026] The lower portion of the furnace shell 107 is equipped with a furnace shell inspection manhole 109 and one to six cooling gas inlets 111 for protecting the furnace shell. Multiple, evenly spaced supports 110 for securing the waste heat recovery boiler are welded to the outer wall of the furnace shell 107. An upwardly projecting, annular, convex head 113 is fixed to the inner bottom of the furnace shell 107 to support the water-cooled wall.
[0027] like Figure 1 , Figure 2The inner water-cooled wall single-sided heating chamber 20 is a cylindrical chamber formed by the inner water-cooled wall 203. It includes: an inlet water spray cooling pipe 201, located at the dusty, high-temperature raw gas inlet 101, for regulating the temperature of the raw gas entering the upstream gasification system. Multiple, evenly distributed inlet water spray cooling pipes 201 are provided. One end of the inlet water spray cooling pipe 201 extends into the dusty, high-temperature raw gas inlet 101, while the other end extends outside the pressure shell 10 and connects to a water pipe. Affixed to the outer side of the inner water-cooled wall 203 are inner water-cooled wall supports 205 for supporting and securing the inner water-cooled wall, and inner water-displacement guide frames 206 for limiting its expansion direction. The inner water-cooled wall supports 205 overlap corresponding supports on the inner side of the outer water-cooled wall, and the inner water-displacement guide frames 206 are plugged into corresponding guide frames on the inner side of the outer water-cooled wall. The inner tube packing seal ring 202, formed between the top of the inner tube water-cooled wall 203 and the dusty, high-temperature raw gas inlet 101, is filled with refractory material, preferably refractory fiber wool, to reduce the amount of cooling shield gas backblowing into the furnace. From the conical top of the inner tube water-cooled wall 203, 4 to 20 groups of inner tube heating tube panels 204 are evenly distributed along the circumference. Each group of inner tube heating tube panels 204 is composed of multiple vertically arranged metal tubes arranged along the radius of the inner tube water-cooled wall's single-sided heating cavity 20. The vertical arrangement of the inner tube heating tube panels 204 parallel to the air inlet direction minimizes dust accumulation on the heated surface of the furnace tubes.
[0028] like Figure 1 , further improved as follows: the inner tube water-cooled wall 203 can be formed by 2 to 9 groups of spirally wound steel pipes, or by steel pipes arranged vertically and parallelly along the circumferential direction, with a certain interval set between adjacent steel pipes, and the interval is connected by welding of flat steel bars.
[0029] like Figure 1 , Figure 2 , further improved as follows: the double-sided heated cavity 30 of the annular gap water-cooled wall is formed by the concentric installation of the inner tube water-cooled wall 203 and the outer tube water-cooled wall 304 to form an annular cavity, including: an outer tube water-cooled wall support 302 for supporting and fixing itself and an outer tube displacement guide frame 303 for limiting its own expansion direction are arranged on the outside of the outer tube water-cooled wall 304, the outer tube water-cooled wall support 302 is overlapped on the water-cooled wall support 106, and the outer tube displacement guide frame 303 is inserted into the displacement guide frame 108.
[0030] The outer tube packing seal ring 301 formed by the top of the inner tube water-cooled wall 203 and the top of the outer tube water-cooled wall 304 is filled with refractory material, preferably refractory fiber cotton, to reduce the amount of backflow of cooling shielding gas into the annular cavity. An annular gap inlet water spray cooling pipe 305 is installed at the bottom of the outer tube water-cooled wall 304 to regulate the temperature of the crude gas after cooling through the single-sided heating cavity of the inner tube water-cooled wall and then redirected to the double-sided heating cavity of the annular gap water-cooled wall. Multiple annular gap inlet water spray cooling pipes 305 are evenly arranged and fixed to the outer tube water-cooled wall 304 via corresponding brackets. One end of each pipe extends into the cavity within the outer tube water-cooled wall 304, and the other end is connected to a water pipe and extends outside the pressure shell 10.
[0031] A layer of high thermal conductivity non-metallic refractory protective layer 306 is laid on the inner surface of the bottom conical section of the outer tube water-cooled wall 304, including the inner surface below the conical section. A corrugated expansion joint 308 is set on the outer surface of the bottom conical section of the outer tube water-cooled wall 304 to absorb the expansion displacement of the outer tube water-cooled wall 304. The interior of the corrugated expansion joint 308 is filled with refractory insulation cotton 307.
[0032] like Figure 1 , further improved as follows: the outer tube water-cooled wall 304 can be formed by 2 to 9 groups of spirally wound steel pipes, or by steel pipes arranged vertically and parallelly along the circumferential direction, with a certain interval set between adjacent steel pipes, and the intervals are fixedly connected by welding with flat steel bars.
[0033] like Figure 1 , further improved as follows, the cooling protection gas ring cavity 40 is formed by the outer tube water-cooled wall 304 and the furnace shell cylinder 107 being concentrically installed to form an annular cavity, including: a 30-80mm furnace shell refractory protection layer 401 is set inside the pressure shell 10.
[0034] like Figure 1 , Figure 2 , further improved as follows: the ash hopper 50 is located at the bottom of the waste heat recovery boiler and is used to collect dust settled in the raw coal gas, including: an ash hopper cylinder 501, an ash hopper conical lower head 502, an ash hopper heat-insulating refractory layer 503 of a certain thickness set on the inner surface of the ash hopper, an ash hopper maintenance manhole 505 is opened on the ash hopper cylinder, and an ash hopper heating coil 504 is set on the ash hopper cylinder and the ash hopper conical lower head.
[0035] Based on the above-mentioned ideal embodiment of the present invention, and in accordance with the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present invention. The technical scope of the present invention is not limited to the content of the specification, but must be determined according to the scope of the claims.
Claims
1. A biomass pressurized gasification waste heat recovery boiler, characterized in that: include: A pressure-bearing shell, wherein an inner tube water-cooled wall and an outer tube water-cooled wall are provided in the pressure-bearing shell, the inner tube water-cooled wall forms a single-sided heating cavity of the inner tube water-cooled wall, an annular gap water-cooled wall double-sided heating cavity is formed between the outer tube water-cooled wall and the inner tube water-cooled wall, a cooling protection gas cavity is formed between the outer tube water-cooled wall and the inner wall of the pressure-bearing shell, an annular convex head is provided in the pressure-bearing shell to separate the lower end of the inner cavity of the pressure-bearing shell into an ash hopper, the ash hopper is connected with the single-sided heating cavity of the inner tube water-cooled wall and the double-sided heating cavity of the annular gap water-cooled wall, a dust-containing high-temperature coal gas inlet is provided at the top of the pressure-bearing shell, a low-temperature raw coal gas outlet connected with the double-sided heating cavity of the annular gap water-cooled wall is provided on the side wall of the pressure-bearing shell, and a cooling protection gas inlet connected with the cooling protection gas cavity is provided on the pressure-bearing shell.
2. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: A plurality of groups of inner tube heated tube panels are evenly arranged along the circumference of the inner wall of the inner tube water-cooled wall.
3. The biomass pressurized gasification waste heat recovery boiler according to claim 2, characterized in that: The inner tube heating tube panel is formed by a plurality of vertically arranged metal tubes arranged along the radial direction of the single-side heating cavity of the inner tube water-cooled wall.
4. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: An inlet water spray cooling pipe is provided on the portion of the dust-laden high-temperature raw gas inlet extending into the inner cavity of the pressure-bearing shell.
5. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: An annular gap inlet water spraying cooling pipe is provided at the bottom of the outer tube water-cooled wall.
6. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: An inner tube displacement guide frame is provided on the outer wall of the inner tube water-cooled wall.
7. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: An outer cylinder displacement guide frame is provided on the outer wall of the outer cylinder water-cooled wall.
8. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: A corrugated expansion joint is provided on the outer surface of the conical section at the bottom of the outer tube water-cooled wall.
9. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: An inner tube packing sealing ring is formed between the top of the inner tube water-cooled wall and the dust-laden high-temperature raw coal gas inlet, and the inner tube packing sealing ring is filled with refractory material.
10. The biomass pressurized gasification waste heat recovery boiler according to claim 1, characterized in that: An outer tube packing sealing ring is formed between the top of the inner tube water-cooled wall and the top of the outer tube water-cooled wall, and the outer tube packing sealing ring is filled with refractory material.