Heat exchange single tube, horizontal flow membrane wall hearth and circulating fluidized bed furnace

Abstract

The application discloses a heat exchange single pipe, a horizontal flow membrane type hearth and a circulating fluidized bed furnace. The application completely solves the problem that the circulating fluidized bed structure cannot be used due to abrasion of the heat carrier heating furnace; the volume pipe arrangement rate of the hearth is increased, the height of the circulating fluidized bed is reduced, manufacturing is convenient, the membrane type hearth is supported by the outer wall membrane type wall, one furnace can be used for multiple purposes, a steam boiler and a heat carrier furnace or a gas heating furnace can be used in one furnace, the heat exchange areas of various heat users can be flexibly arranged in one furnace according to the characteristics of the heat users; the problem that the wall of the heat exchange surface of the flue behind the circulating fluidized bed furnace is frequently blocked is solved by increasing the arrangement area of the hearth and reducing the flue gas outlet temperature of the hearth; the flue gas outlet temperature is reduced, the flue gas volume flow is reduced, the separation efficiency of the cyclone is improved, the heat transfer coefficient is improved; the coking and blocking caused by the secondary combustion in the cyclone separator are avoided, the cyclone does not need jacket cooling, and the start-up and temperature rising time is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of circulating fluidized bed boiler, and particularly relates to a heat exchange single tube, a horizontal flow membrane wall furnace chamber and a circulating fluidized bed boiler. BACKGROUND

[0002] The development and utilization of biomass fuel has become a consensus in the world. Among various biomass energy conversion technologies, direct combustion is one of the most feasible ways for efficient utilization of biomass resources. The circulating fluidized bed combustion technology has unique advantages over other combustion technologies in terms of alternative fuels, treatment of various wastes and environmental protection, and has gradually attracted the attention of various countries.

[0003] Biomass furnace selection

[0004] 1. Pure biomass water-cooled vibrating grate

[0005] Biomass is combusted at low temperature in the furnace, and the furnace temperature is 600-700℃. The decomposition and release of alkali metal salts are controlled by low temperature combustion, which reduces the blockage of the rear flue. It is suitable for medium and low pressure steam boilers with low medium temperature, and the equipment investment is large, the mechanical failure is more, and the combustion thermal efficiency is 15% lower than that of the circulating fluidized bed. For the molten salt heating furnace with a running medium temperature of 430℃ or higher, the investment is multiplied compared to the steam boiler with the same heat.

[0006] 2. Biomass gasification and combustion

[0007] The biomass is gasified by a chain furnace, and the gas is washed with water to remove tar before being sent to the combustion furnace. There are environmental problems of tar wastewater treatment, and the investment is larger and the thermal efficiency is lower than that of the direct combustion vibrating grate.

[0008] The output of the above two furnaces is sensitive to the change of fuel moisture.

[0009] 3. Pure biomass circulating fluidized bed

[0010] There is mature technology for pure biomass circulating fluidized bed steam boiler, but the operation cycle is shorter than that of coal-fired circulating fluidized bed boiler.

[0011] In view of the series of technical and economic advantages of circulating fluidized bed boiler compared with grate furnace: low construction cost; strong fuel adaptability; operation is not restricted by biomass fuel supply; safe and reliable operation; good economy; excellent environmental protection performance; wide load regulation range and other inherent advantages, the biomass circulating fluidized bed is the best way to utilize biomass suitable for China's national conditions.

[0012] But the structure of molten salt heating furnace or heat conducting oil furnace is completely different from that of steam boiler, which is determined by the characteristics of heat transfer medium. The water wall of steam boiler is heated by water vaporization, and the latent heat of water vaporization is large, so the flow rate of water in the tube is low. The water vaporization is easy to form a self-circulating loop, and as long as there is liquid level in the steam drum, the overheating damage of the tube will not occur. The molten salt and heat conducting oil are heated by temperature difference, so the flow rate of the heat transfer medium is high. If the flow rate is low, the overheating damage of the metal tube will occur due to high temperature. Especially for the molten salt heating furnace, the molten salt in the tube should be completely withdrawn into the salt tank when the furnace is stopped, otherwise the molten salt in the tube will solidify and block due to low temperature during the shutdown. Therefore, the structure of the molten salt heating tube cannot have a low point in the form of U-shaped tube, and the tube cannot be vertically arranged like the steam boiler, so that the direction of the tube is consistent with the flow direction of the circulating particles in the furnace. The molten salt tube can only be horizontally arranged or slightly inclined, which will inevitably cause a large impact angle between the flow direction of the circulating particles in the furnace and the tube wall, causing rapid wear of the tube. This is the fundamental reason why the heat carrier furnace does not have a fluidized bed structure. SUMMARY

[0013] Therefore, the present application provides a tube structure arranged horizontally in a fluidized bed and capable of forming a membrane wall, which completely solves the problem of using a fluidized bed structure for a heat carrier heating furnace and opens up a new application way for the application of cheap biomass fuel. The pure biomass circulating fluidized bed structure is adopted for the molten salt furnace or heat conducting oil furnace, which completely solves the problem of scabbing of the heat exchange surface due to low ash melting point of biomass. The membrane wall tube structure is adopted for the circulating fluidized bed molten salt furnace, heat conducting oil furnace or steam boiler, which completely solves the problem of wear of the horizontally arranged tube. Due to the unique membrane wall tube structure, the tube arrangement rate per unit volume in the furnace is greatly improved, a large amount of heat exchange surface can be arranged in the furnace, the heat exchange surface of the rear flue is reduced, and the flue gas outlet temperature of the furnace is reduced to about 450℃, which is 300℃ lower than the flue gas outlet temperature of the current biomass circulating fluidized bed boiler. Due to the low flue gas outlet temperature of the furnace, the gaseous alkali metal salt pyrolyzed during biomass combustion is crystallized on the heat exchange surface in the furnace and becomes solid. At the same time, due to the friction of the circulating particles, the crystalline substance is not adhered to the heat exchange surface, and the corrosion of the alkali metal salt to the high temperature heat exchange surface is greatly reduced. The crystallized alkali metal salt in the solid state is brought into the rear flue, which greatly reduces the crystalline blockage of the heat exchange surface in the rear flue, improves the operation period of the system, and is theoretically higher than the current biomass circulating fluidized bed steam boiler.

[0014] The technical problem to be solved by the present application is how to use a fluidized bed structure for a molten salt furnace or a heat conducting oil furnace.

[0015] In order to solve the above technical problem, the technical scheme of the present application is realized in the following manner:

[0016] A heat exchange single tube, comprising a heat exchange single tube, the middle of the heat exchange single tube is a hollow circle, the hollow circle is a heat transfer medium channel, the upper and lower sides of the heat exchange single tube are concave, and the ratio of the cross-sectional height h of the heat exchange single tube to the width a of the heat exchange single tube is greater than or equal to 2.

[0017] The cross-sectional height h of the heat exchange single tube is equal to 2a+b, b is a coefficient, and b ranges from 1 to 2 mm.

[0018] A horizontal flow membrane hearth, comprising a membrane hearth, the membrane hearth comprises an outer wall membrane and a partition wall membrane in communication with the outer wall membrane, the outer wall membrane comprises a front side membrane, a rear side membrane, a left side membrane and a right side membrane, and the front side membrane, the rear side membrane, the left side membrane and the right side membrane are in communication;

[0019] The left side membrane and the right side membrane are consistent in structure, and the left side membrane and the right side membrane are both formed by corresponding splicing of the upper and lower sides of the heat exchange single tube, and corresponding notches are formed on the upper and lower sides of the heat exchange single tube, and the notches on the upper and lower sides form mounting ports;

[0020] The front side membrane and the rear side membrane are consistent in structure, and the front side membrane and the rear side membrane are both formed by corresponding splicing of the upper and lower sides of the heat exchange single tube, and the two ends of the heat exchange single tube are provided with connectors, the outer dimensions of the connectors are consistent with the dimensions of the mounting ports, and the mounting ports and the connectors are used for assembly and cooperation of the membrane hearth;

[0021] The partition wall membrane is consistent in structure and connection mode with the front side membrane and the rear side membrane, and the partition wall membrane is arranged inside the outer wall membrane.

[0022] The length of the connector is greater than or equal to the width a of the heat exchange single tube.

[0023] One or more heat exchange single tubes in the membrane hearth are in one lead, the heat exchange single tubes in the same lead are connected in parallel, and the heat exchange single tubes in adjacent leads are connected in series.

[0024] A circulating fluidized bed furnace, comprising a membrane hearth, a dense phase combustion section is arranged at the lower part of the membrane hearth, the dense phase combustion section is respectively provided with a feeding device, an ash removal device and a blower, the side surface of the membrane hearth is connected with the inlet of a cyclone separator, the outlet of the cyclone separator is connected with a tail flue, the ash hopper of the cyclone separator is connected with the dense phase combustion section, a heat exchange device is arranged in the tail flue, and an induced draft fan is arranged at the end of the tail flue.

[0025] The membrane type hearth is divided into upper section a, middle section a and lower section a, the upper part of the membrane type hearth is provided with a steam pocket, the outer wall membrane a of the upper section a, the outer wall membrane b of the middle section a and the outer wall membrane c of the lower section a are connected with the steam pocket to form a water evaporation self-circulation loop, the upper half of the outer wall membrane c of the middle section a is a low-temperature superheater, the lower half is a high-temperature superheater, the low-temperature superheater is connected with a temperature regulator, the temperature regulator is connected with the high-temperature superheater, the high-temperature superheater is connected with an external functional device, the external functional device is connected with the steam pocket, and the adjacent guide sections of the outer wall membrane c are connected in series from top to bottom.

[0026] The lower section a is provided with a partition membrane wall f, and the number of the partition membrane wall f is at least 1.

[0027] The membrane type hearth is divided into upper section b, middle section b and lower section b, the outer wall membrane d of the upper section b, the outer wall membrane e of the middle section b and the partition membrane wall e, and the outer wall membrane f of the lower section b are connected in parallel, and the heat transfer medium is molten salt or heat conducting oil; the partition membrane wall d of the upper section b is connected with other heat transfer medium devices.

[0028] The dense phase combustion section takes coal, biomass or a mixture of coal and biomass as fuel.

[0029] Compared with the prior art, the present application has the following advantages: 1. The problem that the circulating fluidized bed structure of the heat carrier heating furnace cannot be used due to wear is completely solved; 2. The volume pipe arrangement rate of the hearth is increased, the height of the circulating fluidized bed is reduced, manufacturing is convenient, the membrane type hearth is supported by the outer wall membrane of the box body itself, unlike the suspended hearth, the workload of on-site construction is greatly reduced, the hearth is manufactured in sections and assembled on site, and the manufacturing cost of the equipment is reduced; 3. It is very easy to realize one furnace with multiple uses, that is, a steam boiler, a heat carrier furnace or a gas heating furnace can be realized in one furnace, the heat exchange area of each user can be flexibly arranged in one furnace according to the characteristics of each heat user, secondary heating is avoided, equipment investment and heat loss are reduced; 4. By increasing the hearth arrangement area, the flue gas outlet temperature of the hearth is reduced, and the problem that the heat exchange surface of the back flue of the biomass circulating fluidized bed boiler and the heat carrier circulating fluidized bed furnace is frequently blocked by wall deposition is solved; 5. The flue gas outlet temperature is reduced, the flue gas volume flow is reduced, the cyclone size is reduced, the separation efficiency of the cyclone is improved, the circulating bed material particles are finer, and the heat transfer coefficient is improved; the coking and blocking in the cyclone separator due to secondary combustion are avoided, the cyclone does not need jacket cooling, the material requirement and manufacturing difficulty of the cyclone separator are reduced, and the start-up and temperature rising time is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structure view of a heat exchange single pipe.

[0031] Figure 2 It is a cross-sectional view of a heat exchange single pipe.

[0032] Figure 3 is a left membrane wall (right membrane wall) structure view.

[0033] Figure 4 is a front membrane wall (back membrane wall) structure view.

[0034] Figure 5 is an outer wall membrane wall structure view.

[0035] Figure 6 is a structure view of a partition wall membrane wall arranged in an outer wall membrane wall.

[0036] Figure 7 is a view of a heat exchange single pipe connection mode.

[0037] Figure 8 is a circulating fluidized bed steam boiler structure diagram taking a 160 tons, 9.8 MPa, 540℃ steam boiler as an example.

[0038] Figure 9 is a heat carrier circulating fluidized bed furnace structure diagram taking a 6 million Kcal / h molten salt furnace for a melamine plant as an example.

[0039] Wherein, 1 is a heat exchange single pipe; 2 is a hollow circle; 3 is a concave surface; 4 is a notch; 5 is a mounting port; 6 is a joint; 7 is a left membrane wall; 8 is a front membrane wall; 9 is a right membrane wall; 10 is a back membrane wall; 11 is a partition wall membrane wall; 12 is a header pipe; 13 is a steam drum; 14 is a cyclone separator; 15 is a heat exchange equipment; 16 is an induced draft fan; 17 is a blower; 18 is a dense phase combustion section; 19 is a feeding device; 20 is an upper section a; 21 is a middle section a; 22 is an outer wall membrane wall b; 23 is a partition wall membrane wall c; 24 is a partition wall membrane wall b; 25 is a lower section a; 26 is an outer wall membrane wall d; 27 is a partition wall membrane wall d; 28 is an upper section b; 29 is a middle section b; 30 is an outer wall membrane wall e; 31 is a partition wall membrane wall e; 32 is a lower section b; 33 is an outer wall membrane wall f. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application.

[0041] In the description of this invention, it should be understood that if directional descriptions are involved, such as up, down, front, back, left, right, etc., indicating the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings, it is only for the convenience of describing this invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0042] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0043] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0044] like Figures 1-2 As shown, a heat exchanger single tube includes a heat exchanger single tube 1, with a hollow circle 2 in the middle of the heat exchanger single tube 1. The hollow circle 2 serves as a heat transfer medium channel. The upper and lower sides of the heat exchanger single tube 1 are concave surfaces 3. The ratio of the cross-sectional height h to the width a of the heat exchanger single tube 1 is greater than or equal to 2. The cross-sectional height h of the heat exchanger single tube 1 is h = 2a + b, where b ranges from 1 to 2 mm. The hollow circle 2 serves as the heat transfer medium channel. This tube is cold-drawn by a specialized manufacturer using a mold. The cross-sectional width a of the heat exchanger single tube is preferably 38 to 54 mm.

[0045] like Figures 3-7 As shown, a horizontally flowing membrane fireplace includes a membrane fireplace, which includes an outer membrane wall and a partition membrane wall 11 connected to the outer membrane wall. The outer membrane walls can be connected to each other through a manifold 12. The outer membrane wall includes a front membrane wall 8, a rear membrane wall 10, a left membrane wall 7, and a right membrane wall 9. The front membrane wall 8, the rear membrane wall 10, the left membrane wall 7, and the right membrane wall 9 are connected through the manifold 12. The outer membrane wall has a rectangular box shape.

[0046] The left membrane wall 7 and the right membrane wall 9 have the same structure. Both the left membrane wall 7 and the right membrane wall 9 are spliced ​​together from the upper and lower sides of the heat exchange tube 1. Corresponding notches 4 are opened on the upper and lower sides of the heat exchange tube 1. The notches 4 on the upper and lower sides form the installation port 5.

[0047] The front membrane wall 8 and the rear membrane wall 10 are consistent in structure, and the front membrane wall 8 and the rear membrane wall 10 are both formed by corresponding splicing of the upper and lower sides of the heat exchange single tube 1. The two ends of the heat exchange single tube 1 are provided with the joint 6, and the outer dimension of the joint 6 is consistent with the dimension of the mounting port 5. The mounting port 5 and the joint 6 are used for assembling and cooperating the membrane wall furnace. The shape of the joint 6 and the mounting port 5 can be cylindrical, square or other shapes, as long as the joint 6 and the mounting port 5 can be used in cooperation, and meanwhile, the use of the membrane wall furnace is not affected.

[0048] The structure and connection mode of the partition membrane wall 11 are consistent with those of the front membrane wall 8 and the rear membrane wall 10. That is, the front membrane wall 8 or the rear membrane wall 10 is connected with the front membrane wall 8 and the rear membrane wall 10 in the same way, and the partition membrane wall 11 is connected with the front membrane wall 8 and the rear membrane wall 10 in the same way. The partition membrane wall 11 is arranged inside the outer wall membrane wall.

[0049] The length of the joint 6 is greater than or equal to the width a of the heat exchange single tube 1. One or more heat exchange single tubes 1 in the membrane wall furnace form a lead, the heat exchange single tubes 1 in the same lead are connected in parallel, and the upper and lower adjacent leads are connected in series. In actual application, the upper and lower adjacent leads are generally connected in series, and parallel connection is basically not used.

[0050] As shown in Figures 8-9 , a circulating fluidized bed furnace includes a membrane wall furnace, and the lower part of the membrane wall furnace is provided with a dense phase combustion section 18. The dense phase combustion section 18 is respectively provided with a feeding device 19, an ash removal device and a blower 17. The side of the membrane wall furnace is connected with the inlet of a cyclone separator 14. The outlet of the cyclone separator 14 is connected with a tail flue. The ash hopper of the cyclone separator 14 is connected with the dense phase combustion section 18. The tail flue is provided with a heat exchange device 15. The tail flue is provided with an induced draft fan 16 at the end.

[0051] As shown in Figure 8As shown, when used as a circulating fluidized bed boiler, the membrane wall furnace is divided into upper section a20, middle section a21 and lower section a25, the upper part of the membrane wall furnace is provided with a steam drum 13, the outer wall membrane a of the upper section a20, the partition wall membrane a, the outer wall membrane b22 of the middle section a21 and the outer wall membrane c of the lower section a25 and the partition wall membrane b24 (used for large-scale boilers) are used as parallel combined vaporization heating surfaces, which are all connected to the steam drum 13 to form a water evaporation self-circulation loop. The upper half of the partition wall membrane c23 of the middle section a21 is a low-temperature superheater, and the lower half is a high-temperature superheater, the low-temperature superheater is connected to a temperature regulator, the temperature regulator is connected to the high-temperature superheater, the high-temperature superheater is connected to an external functional device, and the external functional device is connected to the steam drum 13. The external functional device can be a steam power generation unit for generating power by using steam. The upper and lower adjacent passes in the partition wall membrane c23 adopt a series connection mode of upward flow and downward flow, the number of heat exchange single pipes 1 in a single pass in the partition wall membrane c23 and the number of parallel partition wall membranes c23 are determined according to the flow and allowable resistance of the partition wall membrane c23, and the number of series-connected passes is determined according to the steam temperature requirement.

[0052] The lower section a25 can adopt 1-2 partition wall membranes f under the condition of ensuring the combustion residence time, for increasing the evaporation heating area.

[0053] As shown, Figure 9 As shown, when used as a circulating fluidized bed boiler, the membrane wall furnace is divided into upper section a20, middle section a21 and lower section a25, the upper part of the membrane wall furnace is provided with a steam drum 13, the outer wall membrane a of the upper section a20, the partition wall membrane a, the outer wall membrane b22 of the middle section a21 and the outer wall membrane c of the lower section a25 and the partition wall membrane b24 (used for large-scale boilers) are used as parallel combined vaporization heating surfaces, which are all connected to the steam drum 13 to form a water evaporation self-circulation loop. The upper half of the partition wall membrane c23 of the middle section a21 is a low-temperature superheater, and the lower half is a high-temperature superheater, the low-temperature superheater is connected to a temperature regulator, the temperature regulator is connected to the high-temperature superheater, the high-temperature superheater is connected to an external functional device, and the external functional device is connected to the steam drum 13. The external functional device can be a steam power generation unit for generating power by using steam. The upper and lower adjacent passes in the partition wall membrane c23 adopt a series connection mode of upward flow and downward flow, the number of heat exchange single pipes 1 in a single pass in the partition wall membrane c23 and the number of parallel partition wall membranes c23 are determined according to the flow and allowable resistance of the partition wall membrane c23, and the number of series-connected passes is determined according to the steam temperature requirement.

[0054] The dense phase combustion section 18 uses coal, biomass or a mixture of coal and biomass as fuel.

[0055] According to different characteristics of heat users, the sectional arrangement of multi-purpose of one furnace can be easily realized, different heat transfer medium can be used in different partition membrane walls 11, and multiple heat transfer medium can be directly used in one furnace for heat exchange, which is arranged in sections according to the temperature of the medium, the low temperature medium is arranged on the upper part and the high temperature medium is arranged on the lower part, thus the secondary heat exchange can be reduced, the heat efficiency can be improved and the equipment investment can be reduced; the temperature of the flue gas outlet of the furnace is reduced to about 450℃ and then enters the cyclone separator 14, thus the volume flow of the flue gas can be reduced, the size of the cyclone can be reduced, the separation efficiency of the cyclone can be improved, the particles of the circulating bed material can be finer, the heat transfer coefficient can be improved, the coking and blocking caused by the secondary combustion in the cyclone separator 14 can be avoided, the cyclone does not need jacket cooling, the material requirement and manufacturing difficulty of the cyclone separator 14 are reduced, the start-up and temperature rising time is reduced, the wall blocking and blocking of the heat exchange surface of the rear flue is reduced, the operation cycle of the whole furnace is effectively prolonged.

[0056] The furnace area of the 160t / h, 9.8MPa, 540℃ steam boiler in table 1

[0057]

[0058]

[0059]

[0060] The above only describes the preferred embodiments of the present application, it should be noted that for those skilled in the art, without departing from the overall concept of the present application, several changes and improvements can be made, which should be considered as the protection scope of the present application.

Claims

1. A horizontally flow-to-membrane firebox, characterized by, The furnace includes a membrane fireplace, a heat exchange tube (1), and a manifold (12). The membrane fireplace includes an outer wall membrane wall and a partition wall membrane wall (11) connected to the outer wall membrane wall. The outer wall membrane wall includes a front membrane wall (8), a rear membrane wall (10), a left membrane wall (7), and a right membrane wall (9). The front membrane wall (8), the rear membrane wall (10), the left membrane wall (7), and the right membrane wall (9) are connected by the manifold (12). The heat exchange tube (1) has a hollow circle (2) in the middle, which is a heat transfer medium channel. The upper and lower sides of the heat exchange tube (1) are concave surfaces (3). The ratio of the cross-sectional height h of the heat exchange tube (1) to the width a of the heat exchange tube (1) is greater than or equal to 2. The upper and lower sides of the heat exchange tube (1) are spliced ​​together to form a left membrane wall (7) and a right membrane wall (9).

2. A horizontally flowing membrane firebox as defined in claim 1, wherein, The cross-sectional height of the heat exchange tube (1) is h=2a+b, where b is a coefficient and the range of b is 1~2mm.

3. A horizontally flowing membrane firebox according to any one of claims 1-2, characterized in that The left membrane wall (7) and the right membrane wall (9) have the same structure. Corresponding notches (4) are opened on the upper and lower sides of the heat exchange tube (1). The notches (4) on the upper and lower sides form the installation port (5). The front membrane wall (8) and the rear membrane wall (10) have the same structure. Both the front membrane wall (8) and the rear membrane wall (10) are spliced ​​together from the upper and lower sides of the heat exchange single tube (1). Both ends of the heat exchange single tube (1) are set as joints (6). The external dimensions of the joints (6) are the same as the dimensions of the mounting port (5). The mounting port (5) and the joints (6) are used for the assembly and matching of the membrane furnace. The structure of the partition membrane wall (11) is consistent with the structure and connection method of the front membrane wall (8) and the rear membrane wall (10). The partition membrane wall (11) is set inside the outer wall membrane wall.

4. A horizontally flowing membrane firebox as defined in claim 3, wherein, The length of the joint (6) is greater than or equal to the width a of the heat exchange tube (1).

5. A circulating fluidized bed boiler comprising a horizontal flow to membrane wall furnace according to any of claims 3 to 4, characterized in that, The furnace includes a membrane fireplace, with a dense phase combustion section (18) at the bottom. The dense phase combustion section (18) is equipped with a feeding device (19), a cleaning device and a blower (17). The side of the membrane fireplace is connected to the inlet of a cyclone separator (14), the outlet of the cyclone separator (14) is connected to the tail flue, the ash hopper of the cyclone separator (14) is connected to the dense phase combustion section (18), a heat exchange device (15) is installed in the tail flue, and an induced draft fan (16) is installed at the end of the tail flue.

6. A circulating fluid bed furnace according to claim 5, wherein The membrane fireplace is divided into an upper section a (20), a middle section a (21) and a lower section a (25). A steam drum (13) is installed in the upper part of the membrane fireplace. The outer wall membrane wall a and the partition membrane wall a of the upper section a (20), the outer wall membrane wall b (22) of the middle section a (21), and the outer wall membrane wall c and the partition membrane wall b (24) of the lower section a (25) are all connected to the steam drum (13) to form a water evaporation self-circulation loop. The upper half of the partition membrane wall c (23) of the middle section a (21) is a low-temperature superheater, and the lower half is a high-temperature superheater. The low-temperature superheater is connected to the thermostat, the thermostat is connected to the high-temperature superheater, the high-temperature superheater is connected to the external functional device, and the external functional device is connected to the steam drum (13).

7. A circulating fluid bed furnace according to claim 6, characterised in that The lower section a (25) is provided with a partition membrane wall f, and the number of the partition membrane wall f is at least 1.

8. A circulating fluid bed furnace according to claim 5, wherein The dense phase combustion section (18) uses coal, biomass or a mixture of coal and biomass as fuel.

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