A supercritical superheated steam gas injection boiler and heat exchange method thereof

Abstract

The present invention belongs to the technical field of steam boilers, and discloses a supercritical superheated steam injection boiler and a heat exchange method thereof, wherein the supercritical superheated steam injection boiler comprises a furnace, a fuel burner is arranged at the top of the furnace, a lower side wall of the furnace is arranged as a membrane water-cooled wall, an outer sealing cover of the membrane water-cooled wall is provided with a smoke barrier wall having a bottom, an annular heat exchange channel is formed between the back-fire side of the membrane water-cooled wall and the smoke barrier wall, a smoke channel is formed between the lower end of the membrane water-cooled wall and the bottom of the smoke barrier wall, and a horizontal flue is connected to the upper side of the smoke barrier wall. The present invention improves the furnace of the existing supercritical superheated steam injection boiler, wherein the inner side surface and the back-fire surface of the membrane water-cooled wall are uniformly and efficiently heat exchanged, so that the heat exchange area required for the membrane water-cooled wall is reduced, so that a relatively low-height membrane water-cooled wall can be used, thereby reducing the height of the furnace, and reducing the space occupied and weight of the supercritical superheated steam injection boiler.

Description

Technical Field

[0001] The invention belongs to the technical field of steam boilers, and in particular relates to a supercritical superheated steam injection boiler and a heat exchange method thereof. Background Art

[0002] Offshore heavy oil development uses high-temperature and high-pressure steam injected into the formation to heat the formation and heavy oil, so as to reduce the viscosity of crude oil and increase the fluidity of crude oil in the formation, so as to achieve the goal of economic recovery of heavy oil. At present, offshore heavy oil thermal recovery platforms mainly use supercritical superheated steam injection boilers to generate high-temperature and high-pressure steam, and inject high-temperature and high-pressure steam into the formation through ground process manifolds, Christmas trees, and insulated oil pipes.

[0003] At present, the problems existing in the boilers of offshore heavy oil thermal recovery platforms are as follows: the space of offshore heavy oil thermal recovery platforms is limited, and the supercritical superheated steam injection boilers currently used are mostly based on the horizontal boilers used in land heavy oil thermal recovery platforms. They occupy a large space and are relatively heavy, which will increase the volume and weight of the offshore heavy oil thermal recovery platform, resulting in increased design difficulty and relatively increased investment costs for the offshore heavy oil thermal recovery platform. Therefore, there is an urgent need to develop boilers with smaller space occupancy and weight. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a supercritical superheated steam injection boiler and a heat exchange method thereof. The present invention improves the furnace of the existing supercritical superheated steam injection boiler, so that the height of the furnace can be reduced, thereby reducing the space occupied and the weight of the supercritical superheated steam injection boiler.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A supercritical superheated steam injection boiler comprises a furnace, a fuel burner is arranged on the top of the furnace, the lower side wall of the furnace is arranged as a membrane water-cooled wall, the outer sealing cover of the membrane water-cooled wall is provided with a smoke barrier wall with a bottom, an annular heat exchange channel is formed between the back-fire side of the membrane water-cooled wall and the smoke barrier wall, a smoke channel is formed between the lower end of the membrane water-cooled wall and the bottom of the smoke barrier wall, and the upper side of the smoke barrier wall is connected to a horizontal flue.

[0007] Preferably, a heat exchange tube is provided on the back-fire side of the membrane water-cooled wall, the inlet of the heat exchange tube is connected to the outlet of the membrane water-cooled wall, and the outlet of the heat exchange tube is connected to a steam-water separator.

[0008] Preferably, the heat exchange tubes are arranged in a vertically arranged heat exchange tube bundle, and the heat exchange tube bundle is distributed at intervals along the circumference of the membrane water-cooled wall.

[0009] Preferably, the heat exchange tube adopts a spiral heater, and the spiral heater is wound around the back-fire side of the membrane water-cooled wall.

[0010] Preferably, a high-temperature superheater is provided on the horizontal flue, and the steam outlet of the steam-water separator is connected to the steam inlet of the high-temperature superheater.

[0011] Preferably, a compressed air preheater is provided on the horizontal flue downstream of the high-temperature superheater, and the compressed air outlet of the compressed air preheater is connected to the compressed air inlet of the oil burner.

[0012] Preferably, an economizer is also provided on the horizontal flue, and the economizer is located downstream of the high-temperature superheater and upstream of the compressed air preheater, and the water outlet of the economizer is connected to the inlet of the membrane water-cooled wall.

[0013] Preferably, the supercritical superheated steam gas injection boiler of the present invention further comprises a water treatment device for evaporating and purifying seawater, wherein a heater for evaporating and purifying seawater is provided in the water treatment device;

[0014] An energy saver is also provided on the horizontal flue. The energy saver is located downstream of the economizer and upstream of the compressed air preheater. The energy saver is connected to the heater of the water treatment device.

[0015] Preferably, the fresh water outlet of the water treatment device is connected to the water inlet of the economizer, and a water pump is provided on the pipeline connecting the fresh water outlet of the water treatment device and the water inlet of the economizer.

[0016] The present invention also provides a heat exchange method for the supercritical superheated steam gas injection boiler, comprising the following process:

[0017] The flue gas in the furnace flows downward and exchanges heat with the membrane water-cooled wall. When the flue gas flows downward to the lower end of the membrane water-cooled wall, it flows into the heat exchange channel from the flue gas channel. The flue gas entering the heat exchange channel flows from bottom to top and is discharged through the horizontal flue. When the flue gas flows from bottom to top in the heat exchange channel, the flue gas exchanges heat with the back-fire side of the membrane water-cooled wall.

[0018] The present invention has the following beneficial effects:

[0019] In the supercritical superheated steam injection boiler of the present invention, the lower side wall of the furnace is set as a membrane water-cooled wall, and the membrane water-cooled wall can perform heat exchange during the fuel burning process in the furnace; by setting the smoke barrier wall of the present invention, a flue gas channel is formed between the bottom of the smoke barrier wall and the lower end of the membrane water-cooled wall, and an annular heat exchange channel is formed between the bottom of the smoke barrier wall and the lower end of the membrane water-cooled wall, and an annular heat exchange channel is formed between the bottom of the smoke barrier wall and the back-fire side of the membrane water-cooled wall, and the upper side of the smoke barrier wall is connected to a horizontal flue, so that when the flue gas in the furnace is discharged, it will flow out through the above-mentioned smoke channel, heat exchange channel and horizontal flue in sequence, so that when the flue gas flows, it will exchange heat with the lower end and the back-fire side of the membrane water-cooled wall again, which greatly improves the effective heat exchange area and heat exchange efficiency of the membrane water-cooled wall, thereby improving the heat exchange efficiency of the entire furnace, so under the condition of a certain heat exchange efficiency, the present invention can adopt a membrane water-cooled wall with a smaller height, so that the height of the entire furnace can be reduced, and at the same time, the weight of the smaller membrane water-cooled wall is relatively light, so the present invention also reduces the weight of the furnace, thereby reducing the weight of the entire supercritical superheated steam injection boiler. It can be seen from the above scheme that the present invention can reduce the height of the furnace by improving the furnace of the existing supercritical superheated steam injection boiler, thereby reducing the space occupied and the weight of the supercritical superheated steam injection boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of a supercritical superheated steam gas injection boiler in an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of the furnace in an embodiment of the present invention.

[0023] In the figure, 1-oil burner, 2-furnace, 3-membrane water-cooled wall, 4-spiral heater, 5-steam-water separator, 6-high-temperature superheater, 7-economizer, 8-energy saver, 9-compressed air preheater, 10-water treatment device, 11-water pump, 12-smoke barrier wall, 13-heat exchange channel, 14-smoke channel, 15-horizontal flue, 16-insulation section. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] See also Figure 1The supercritical superheated steam injection boiler of this embodiment includes a furnace 2, a fuel burner 1 is provided on the top of the furnace 2, a lower side wall of the furnace 2 is set as a membrane water-cooled wall 3, and the upper part of the furnace 2 is still an insulation section 16. The fuel burner 1 is located at the top of the insulation section 16. The external sealing cover of the membrane water-cooled wall 3 is provided with a smoke barrier wall 12 with a bottom, and an annular heat exchange channel 13 is formed between the back-fire side of the membrane water-cooled wall 3 and the smoke barrier wall 12. A smoke channel 14 is formed between the lower end of the membrane water-cooled wall 3 and the bottom of the smoke barrier wall 12, and the upper side of the smoke barrier wall 12 is connected with a horizontal flue 15.

[0026] When the supercritical superheated steam gas injection boiler of the above embodiment is working, the fuel (such as heavy oil) and the combustion-supporting gas are burned at the top of the furnace 2 through the oil burner 1, and the flue gas generated by the combustion flows downward and exchanges heat with the inner side of the membrane water-cooled wall 3. When the flue gas flows downward to the lower end of the membrane water-cooled wall 3, it flows into the heat exchange channel 13 from the flue gas channel 14. The flue gas entering the heat exchange channel 13 flows from bottom to top and is discharged through the horizontal flue 15; when the flue gas flows from bottom to top in the heat exchange channel 13, the flue gas exchanges heat with the back-fire side of the membrane water-cooled wall 3.

[0027] In the above scheme, the flue gas generated by the combustion in the furnace 2 exchanges heat with the inner side of the membrane water-cooled wall 3, as well as the lower end face and the back-fire side (i.e., the outer side) of the membrane water-cooled wall 3, thereby greatly improving the effective heat exchange area and heat exchange efficiency of the membrane water-cooled wall 3, thereby improving the overall heat exchange efficiency of the supercritical superheated steam injection boiler of the present invention. Therefore, under the condition of a certain heat demand, the present invention can adopt a membrane water-cooled wall 3 of a lower height to ensure the heat exchange efficiency, so the required volume of the membrane water-cooled wall 3 will also be reduced, thereby reducing the overall volume of the supercritical superheated steam injection boiler of the present invention, and also reducing the weight, thereby realizing the compactness of the supercritical superheated steam injection boiler. In addition, the inner side of the membrane water-cooled wall 3 and the back-fire surface are both heat exchanged, so the temperature difference between the inner side of the membrane water-cooled wall 3 and the back-fire surface is relatively reduced, thereby reducing the thermal stress inside the membrane water-cooled wall 3 and improving the life of the membrane water-cooled wall 3.

[0028] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, the overall shape of the smoke barrier wall 12 is a pen holder shape without an upper bottom, the smoke barrier wall 12 is sleeved on the outside of the membrane water-cooled wall 3, and the upper end of the smoke barrier wall 12 is sealed and connected with the upper end of the membrane water-cooled wall 3 to prevent smoke from escaping; there is a distance between the lower end of the membrane water-cooled wall 3 and the bottom of the smoke barrier wall 12 to form a flue gas channel 14, and there is a distance between the inner wall of the smoke barrier wall 12 and the outer wall of the membrane water-cooled wall 3, so that a heat exchange channel 13 is formed between the inner wall of the smoke barrier wall 12 and the outer wall of the membrane water-cooled wall 3, and the heat exchange channel 13 is connected with the inner cavity of the furnace 2 through the above-mentioned flue gas channel 14. The connection position of the horizontal flue 15 and the smoke barrier wall 12 is as close as possible to the upper end of the membrane water-cooled wall 3, so that the back-fire side of the membrane water-cooled wall 3 participates in heat exchange as much as possible.

[0029] As a preferred embodiment of the present invention, based on the above embodiments, in this embodiment, the shape of the heat exchange channel 13 is related to the shape of the overall cross-section of the furnace 2. When the overall cross-section of the furnace 2 is circular, the shape of the heat exchange channel 13 is a circular ring; when the overall cross-section of the furnace 2 is rectangular, the shape of the heat exchange channel 13 is a U-shape; when the overall cross-section of the furnace 2 is other shapes, the shape of the smoke barrier wall 12 can also be similar to the overall cross-section of the furnace 2, and finally the heat exchange channel 13 is still an annular chamber.

[0030] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, a heat exchange tube is provided on the back-fire side of the membrane water-cooled wall 3, the inlet of the heat exchange tube is connected to the outlet of the membrane water-cooled wall 3, and the outlet of the heat exchange tube is connected to a steam-water separator 5, wherein the steam-water separator 5 can separate the water vapor and liquid water in the heat exchange tube. The liquid water separated by the steam-water separator 5 can continue to be used as a hot water source for other equipment, or continue to be sent to the membrane water-cooled wall 3 and / or the heat exchange tube for circulating heat exchange; the water vapor separated by the steam-water separator 5 is used as a steam gas source for heavy oil exploitation in the seabed stratum. In this embodiment, the heat exchange tube can exchange heat with the flue gas in the heat exchange channel 13, can further recover the heat in the flue gas, and improve the heat exchange efficiency of the entire supercritical superheated steam injection boiler. Under the condition of a certain steam demand, this embodiment can further reduce the volume of the furnace 2 and the membrane water-cooled wall 3, thereby reducing the volume of the entire supercritical superheated steam injection boiler. It can be seen that this embodiment further reduces the area occupied by the auxiliary equipment of the offshore heavy oil thermal recovery platform, reserves a larger space for the oil production equipment of the offshore heavy oil thermal recovery platform, and can greatly improve the oil production and oil production efficiency per unit time.

[0031] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, the heat exchange tubes can adopt a heat exchange tube bundle arranged vertically, and the heat exchange tube bundle is distributed at intervals along the circumference of the membrane water-cooled wall 3. Generally, in the heat exchange tube bundle, the lower ends of all vertically arranged pipes are connected to a water inlet distribution pipe, and the upper ends are connected to a water outlet collection pipe, the water inlet distribution pipe is connected to the outlet of the membrane water-cooled wall 3, and the water outlet collection pipe is connected to the inlet of the steam-water separator 5; in the heat exchange tube bundle, the water in the pipe can exchange heat with the flue gas in the heat exchange channel 13, which greatly improves the heat exchange efficiency.

[0032] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, considering that the upper side of the smoke barrier wall 12 is connected to the horizontal flue 15, one side of the horizontal flue 15 belongs to the low-pressure side, and the smoke in the furnace 2 will preferentially flow to the side of the horizontal flue 15 when flowing out. Figure 1 , when the flue gas in the furnace 2 passes through the flue gas channel 14 and the heat exchange channel 13, it will preferentially flow to the right side. At this time, it will cause uneven distribution of flue gas in the flue gas channel 14 and the heat exchange channel 13, and then cause uneven heat exchange between the flue gas and the back-fire side of the heat exchange channel 13 and the heat exchange tube bundle in the previous embodiment. Since the heat exchange channel 13 also belongs to the high-temperature heat exchange section of the flue gas, if the heat exchange is uneven, it will produce greater thermal stress on the above-mentioned heat exchange tubes and the membrane water-cooled wall 3, and reduce their heat exchange efficiency. Therefore, in this embodiment, the heat exchange tube adopts a spiral heater 4, which is a spiral heat exchange tube wound around the back-fire side of the membrane water-cooled wall 3. The advantage of the spiral heat exchange tube is that the heat exchange medium (i.e., water) therein flows in a circle in the circumferential direction of the membrane water-cooled wall 3, so for the spiral heater As for the heat exchanger 4 itself, in its circumferential direction, due to the circular motion of the heat exchange medium, the temperature distribution of the spiral heater 4 in the circumferential direction is more uniform, and the uniformity of heat absorption of the heat exchange medium in the spiral heater 4 is also ensured; at the same time, for the membrane water-cooled wall 3, the spiral heater 4 can also circumferentially heat the back-fire side of the membrane water-cooled wall 3, so that the temperature of the back-fire side of the membrane water-cooled wall 3 in the circumferential direction tends to be uniform. The above-mentioned structural setting of this embodiment can not only improve the heat exchange efficiency of the spiral heater 4 and the membrane water-cooled wall 3, but also avoid the membrane water-cooled wall 3 and the conventional heat exchange tube (such as the above-mentioned heat exchange tube bundle) from over-temperature explosion or local high temperature due to the uneven distribution of flue gas in the heat exchange channel 13. Therefore, the above-mentioned structure of this embodiment can improve the service life of the spiral heater 4 and the membrane water-cooled wall 3. In addition, since the spiral heater 4 can further exchange heat with the flue gas, under the condition of a certain heat demand, the heat exchange area required by the membrane water-cooled wall 3 can be further reduced, and the height of the membrane water-cooled wall 3 can be further reduced.

[0033] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, a high-temperature superheater 6 is provided on the horizontal flue 15, and the steam outlet of the steam-water separator 5 is connected to the steam inlet of the high-temperature superheater 6. The high-temperature superheater 6 can further heat the water vapor separated by the steam-water separator 5, thereby further increasing the water vapor temperature and the thermal efficiency of the entire supercritical superheated steam injection boiler. After the water vapor temperature is further increased, it is also helpful for the fluidity of the heavy oil in the seabed formation, and is helpful for the exploitation of the heavy oil in the bottom layer of the seabed.

[0034] As a preferred embodiment of the present invention, since the fuel burned by the offshore gas injection boiler (i.e., the supercritical superheated steam gas injection boiler of the present invention) is heavy oil, the heavy oil makes the atomization effect of the oil burner 1 poor and the combustion characteristics poor; in order to improve the atomization effect of the oil burner 1, on the basis of the above embodiment, this embodiment is provided with a compressed air preheater 9 on the horizontal flue 15, and the compressed air preheater 9 is arranged downstream of the high-temperature superheater 6, and the compressed air outlet of the compressed air preheater 9 is connected to the compressed air inlet of the oil burner 1, and the compressed air preheater 9 can be used to preheat the compressed air required by the oil burner 1, thereby improving the atomization and combustion effects of the oil burner 1, and thus improving the combustion efficiency.

[0035] As a preferred embodiment of the present invention, on the basis of the above embodiments, in this embodiment, an economizer 7 is further provided on the horizontal flue 15. The economizer 7 is located downstream of the high-temperature superheater 6 and upstream of the compressed air preheater 9. The water outlet of the economizer 7 is connected to the inlet of the membrane water-cooled wall 3. The economizer 7 can be used to further recover the heat carried by the flue gas in the horizontal flue 15. At the same time, the economizer 7 can also be used to preheat the heat exchange medium (such as water) required by the membrane water-cooled wall 3 to avoid damage caused by overcooling of the membrane water-cooled wall 3.

[0036] As a preferred embodiment of the present invention, on the basis of the above embodiment, this embodiment further provides a water treatment device 10 for evaporating and purifying seawater, and a heater for evaporating and purifying seawater is provided in the water treatment device 10. The water treatment device 10 can use the heater to evaporate seawater, so that the seawater is desalinated to meet the fresh water demand of the offshore heavy oil thermal recovery platform; at the same time, since the water used by the existing offshore gas injection boiler is seawater that is reused after water treatment, the water treatment cost is relatively high, so this embodiment also provides an energy saver 8 on the horizontal flue 15, the energy saver 8 is located downstream of the economizer 7 and upstream of the compressed air preheater 9, the energy saver 8 is connected to the heater of the water treatment device 10, and the energy saver 8 can exchange heat with the flue gas in the horizontal flue 15 and heat the heater of the water treatment device 10. This structural design can effectively utilize flue gas preheating, reduce the consumption of additional energy for seawater treatment, and thus reduce the cost of seawater treatment.

[0037] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, the fresh water outlet of the water treatment device 10 is connected to the water inlet of the economizer 7, and a water pump 11 is provided on the pipeline connecting the fresh water outlet of the water treatment device 10 and the water inlet of the economizer 7. In other words, the heat exchange medium in the economizer 7 can use the fresh water treated by the water treatment device 10, wherein the water pump 11 transports the relatively low temperature fresh water in the water treatment device 10 to the economizer 7, and heats it by the economizer 7, and then transports it to the membrane water-cooled wall 3 for heat exchange.

[0038] Example

[0039] The supercritical superheated steam injection boiler of this embodiment includes a furnace 2, the cross-sectional shape of which is circular, the upper half of the furnace 2 is set as an insulation section 16, the top of the insulation section 16 is provided with an oil burner 1, the lower half of the furnace 2 is set as a membrane water-cooled wall 3, the outer cover of the membrane water-cooled wall 3 is provided with a smoke barrier wall 12 with a bottom, the overall shape of the smoke barrier wall 12 is a cylindrical pen holder shape without an upper bottom, the upper end of the smoke barrier wall 12 is sealedly connected to the upper end of the membrane water-cooled wall 3, and a distance is left between the lower end of the membrane water-cooled wall 3 and the bottom of the smoke barrier wall 12, forming a flue gas channel 14; there is a distance between the inner wall of the smoke barrier wall 12 and the outer wall of the membrane water-cooled wall 3, so that an annular heat exchange channel 13 is formed between the inner wall of the smoke barrier wall 12 and the outer wall of the membrane water-cooled wall 3, and the upper end of the smoke barrier wall 12 is connected to the horizontal flue 15. In the heat exchange channel 13, the spiral heater 4 is arranged on the back-fire side of the membrane water-cooled wall 3, the inlet of the spiral heater 4 is connected to the outlet of the membrane water-cooled wall 3, the outlet of the spiral heater 4 is connected to the inlet of the steam-water separator 5, and the liquid water outlet of the steam-water separator 5 is connected to the inlet of the membrane water-cooled wall 3. The horizontal flue 15 is provided with a high-temperature superheater 6, an economizer 7, an economizer 8 and a compressed air preheater 9 in sequence along the flue gas flow direction, wherein the steam outlet of the steam-water separator 5 is connected to the steam inlet of the high-temperature superheater 6, the compressed air outlet of the compressed air preheater 9 is connected to the compressed air inlet of the oil burner 1; the economizer 8 is connected to the heater of the water treatment device 10; the fresh water outlet of the water treatment device 10 is connected to the water inlet of the economizer 7, and a water pump 11 is arranged on the connected pipeline. The water outlet of the economizer 7 is connected to the inlet of the membrane water-cooled wall 3.

[0040] In the supercritical superheated steam gas injection boiler of this embodiment, in the lower half area of ​​the furnace, the high-temperature flue gas generated in the furnace 2 first exchanges heat with the inner side of the membrane water-cooled wall 3, and then flows into the heat exchange channel 13 through the flue gas channel 14. The flue gas exchanges heat with the back-fire side of the membrane water-cooled wall 3 and the spiral heater 4 in the heat exchange channel 13, thereby achieving the maximum heat exchange effect of the membrane water-cooled wall 3, thereby greatly reducing the effective heat exchange area required when only the inner side of the membrane water-cooled wall 3 is used for heat exchange, and then reducing the actual heat exchange area of ​​the membrane water-cooled wall 3. Therefore, a membrane water-cooled wall 3 with a relatively low height can be used, thereby shortening the overall length of the furnace 2. After thermal calculation and numerical simulation, when the lower half area of ​​the furnace 2 (i.e., the membrane water-cooled wall 3) accounts for 50% of the length of the entire furnace 2, the supercritical superheated steam gas injection boiler with the same capacity can reduce the length by 20%~25%, the overall floor space by 30%~40%, and the weight by 40%~45%.

[0041] In the supercritical superheated steam injection boiler of this embodiment, the flue gas after heat exchange in the heat exchange channel 13 flows into the horizontal flue 15, and the steam separated by the steam-water separator 5 enters the high-temperature superheater 6. The steam entering the high-temperature superheater 6 absorbs the heat in the flue gas in the horizontal flue 15 and is converted into superheated high-temperature steam (450-460°C), which is injected into the seabed formation for heavy oil production; the flue gas in the horizontal flue 15 absorbs heat through the high-temperature superheater 6, and the temperature drops to 750-780°C. The flue gas in the horizontal flue 15 absorbs heat through the economizer 7, and the temperature drops to 600-630°C. The flue gas in the horizontal flue 15 is used to heat the water in the economizer 7 to a boiler underheat of 15-20°C, and then the water heated by the economizer 7 is sent to the membrane water-cooled wall 3 to promote the water to enter the membrane water-cooled wall 3 and absorb heat, so that it can be quickly heated to saturated steam (370-375°C), thereby further reducing the volume and weight of the furnace 2; the flue gas in the horizontal flue 15 passes through the economizer 8, and the temperature drops to 320-330°C. The heat exchange medium in the economizer 8 can further absorb the waste heat in the flue gas, and the heat exchange medium is circulated, and the heat is transferred to the water treatment device 10 by the heat exchange medium, so as to provide heat for water quality treatment and reduce the cost of seawater treatment. The flue gas in the horizontal flue 15 finally passes through the air preheater 9, and the temperature drops to 140-150°C. The air preheater 9 can heat the compressed air used to atomize the heavy oil, which is beneficial to the efficient combustion of the heavy oil. It effectively solves the problem in the prior art that the heavy oil is poorly atomized and is easily coked and contaminated when burned in the furnace, affecting the boiler efficiency and evaporation amount.

[0042] In summary, the supercritical superheated steam injection boiler proposed in the present invention has a unique structural design, high heat exchange efficiency in the furnace, relatively small furnace volume, and high energy utilization rate, which effectively and thoroughly solves the problem that the offshore heavy oil thermal recovery platform has a large volume and weight when using horizontal boilers.

[0043] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A supercritical superheated steam gas injection boiler, characterized in that: It comprises a furnace (2), a fuel burner (1) is provided at the top of the furnace (2), a lower side wall of the furnace (2) is arranged as a membrane water-cooled wall (3), an outer sealing cover of the membrane water-cooled wall (3) is provided with a smoke barrier wall (12) having a bottom, an annular heat exchange channel (13) is formed between the back-fire side of the membrane water-cooled wall (3) and the smoke barrier wall (12), a smoke channel (14) is formed between the lower end of the membrane water-cooled wall (3) and the bottom of the smoke barrier wall (12), and a horizontal flue (15) is connected to the upper side of the smoke barrier wall (12); A heat exchange tube is provided on the back-fire side of the membrane water-cooled wall (3), and an inlet of the heat exchange tube is connected to an outlet of the membrane water-cooled wall (3); The heat exchange tube adopts a spiral heater (4), and the spiral heater (4) is wound around the back-fire side of the membrane water-cooled wall (3).

2. A supercritical superheated steam gas injection boiler according to claim 1, characterized in that: The outlet of the heat exchange tube is connected to a steam-water separator (5).

3. The supercritical superheated steam gas injection boiler according to claim 2, characterized in that: A high-temperature superheater (6) is provided on the horizontal flue (15), and the steam outlet of the steam-water separator (5) is connected to the steam inlet of the high-temperature superheater (6).

4. The supercritical superheated steam gas injection boiler according to claim 3, characterized in that: A compressed air preheater (9) is provided on the horizontal flue (15) downstream of the high-temperature superheater (6), and a compressed air outlet of the compressed air preheater (9) is connected to a compressed air inlet of the oil burner (1).

5. The supercritical superheated steam gas injection boiler according to claim 4, characterized in that: The horizontal flue (15) is also provided with an economizer (7), which is located downstream of the high-temperature superheater (6) and upstream of the compressed air preheater (9), and the water outlet of the economizer (7) is connected to the inlet of the membrane water-cooled wall (3).

6. The supercritical superheated steam gas injection boiler according to claim 5, characterized in that: It also includes a water treatment device (10) for evaporating and purifying seawater, wherein a heater for evaporating and purifying seawater is provided in the water treatment device (10); An economizer (8) is also provided on the horizontal flue (15). The economizer (8) is located downstream of the economizer (7) and upstream of the compressed air preheater (9). The economizer (8) is connected to a heater of the water treatment device (10).

7. The supercritical superheated steam gas injection boiler according to claim 6, characterized in that: The fresh water outlet of the water treatment device (10) is connected to the water inlet of the economizer (7), and a water pump (11) is provided on the pipeline connecting the fresh water outlet of the water treatment device (10) and the water inlet of the economizer (7).

8. A heat exchange method for a supercritical superheated steam gas injection boiler, based on the supercritical superheated steam gas injection boiler according to any one of claims 1 to 7, characterized in that: The process includes the following: The flue gas in the furnace (2) flows downward and exchanges heat with the membrane water-cooled wall (3). When the flue gas flows downward to the lower end of the membrane water-cooled wall (3), it flows into the heat exchange channel (13) from the flue gas channel (14). The flue gas entering the heat exchange channel (13) flows from bottom to top and is discharged through the horizontal flue (15). When the flue gas flows from bottom to top in the heat exchange channel (13), the flue gas exchanges heat with the back-fire side of the membrane water-cooled wall (3).

Images