Oilfield gas steam injection boiler

Abstract

The invention discloses an oilfield gas steam injection boiler, comprising a radiation section, a convection section, and a condensation section arranged along the flow direction of flue gas, wherein the convection section is provided with a convection section light pipe and a convection section finned tube, and a high dry section is added between the convection section light pipe and the convection section finned tube, wherein the high dry section is provided with a high dry section light pipe and a high dry section finned tube, and the flue gas passes through the radiation section, the convection section light pipe, the high dry section light pipe, the high dry section finned tube, the convection section finned tube, and the condensation section heat exchange light pipe in sequence. The flue gas condenser can further reduce the flue gas temperature, absorb the latent heat of vaporization of water vapor in the flue gas, form condensed water, and improve the boiler efficiency to more than 100%. By optimizing the heating surface and designing the flue structure, the heat exchange ratio of the radiation section and the convection section is optimized to 5:5, and the heat exchange is more in line with the heat release characteristics of the natural gas flame. The tail flue gas resistance is reduced by three different forms of pressure reduction during the flue gas flow process.

Description

Technical Field

[0001] The invention relates to the technical field of oil field steam injection boilers, in particular to an oil field gas steam injection boiler. Background Art

[0002] The existing oil field steam injection boiler is usually a horizontal direct current water tube boiler, which is mainly composed of a radiation section, a transition section connected to the tail of the radiation section, and a convection section arranged above the transition section. The inner wall of the radiation section is lined with aluminum silicate refractory fiber and is provided with reciprocating coils to form a spacious furnace in the middle; the convection section is a rectangular structure composed of a light tube and a finned tube; the transition section is a semicircular flue gas turning channel connected between the radiation section and the convection section, with an axial size of about 1.3 meters and no heat exchange function.

[0003] The gas-fired steam injection boilers currently in use are large in size, mainly reflected in the axial length of the radiation section and the height of the flue gas outlet from the ground. The dimensions in both directions are large, which is not conducive to the flexible steam injection requirements of heavy oil blocks.

[0004] The existing gas boilers are converted from oil-fired boilers, and the heat exchange surface is mainly based on the characteristics of oil combustion. After changing to natural gas fuel, the heat exchange characteristics and flue gas characteristics have changed and cannot meet the current high-efficiency and energy-saving requirements.

[0005] The heat-carrying mechanism of water vapor shows that the higher the steam dryness, the more heat it carries, and the more obvious the effect of heavy oil steam injection. The direct-flow gas boiler used in oil fields is restricted by the existing process, and conventional water treatment cannot achieve direct dry operation.

[0006] Therefore, the development of a novel oilfield high-efficiency gas-fired steam injection boiler technology is extremely urgent, and it is necessary to provide an oilfield gas-fired steam injection boiler to overcome the above-mentioned defects.

[0007] Publication (announcement) number: CN101343989B, Publication (announcement) date: 2012-08-22 A high-dryness oilfield steam injection boiler and a high-dryness steam production method. The high-dryness oilfield steam injection boiler includes a radiation section, a convection section and a transition section, and also includes a furnace body, a feed water pump and a steam-water separator; a steam superheater is fixedly installed in the furnace body between the convection section and the transition section; the water inlet of the convection section inlet pipe is connected to the water outlet of the feed water pump, and the water outlet of the convection section inlet pipe is connected to the water inlet of the upper end of the convection section; the steam inlet of the convection section outlet pipe is connected to the steam outlet at the lower end of the convection section, and the steam outlet of the convection section outlet pipe is connected to the steam inlet of the radiation section. The invention has a reasonable and compact structure and is easy to use. It can make the steam dryness reach 100% and have a certain superheat, and can meet the steam injection process requirements of super-heavy oil development. Therefore, it greatly improves the working efficiency of steam injection in super-heavy oil development, improves thermal efficiency, reduces energy consumption, and reduces production costs.

[0008] Publication (announcement) number: CN101551097A, Publication (announcement) date: 2009-10-07 A steam injection boiler for producing high-dryness superheated steam is provided, which is composed of a heat exchanger, a radiation section, a convection section, a chimney, a water-placed steam-water separator, a superheater, a furnace body, a water supply pipeline, a burner, an electric heater, an oil heater and a flash tank. A burner is provided at the front of the furnace body, a radiation section is provided in the middle, and a convection section is provided at the rear. The burner is connected to the electric heater and the oil heater respectively through wires and pipelines; a heat exchanger is provided outside the radiation section, an external steam-water separator is provided at the outlet, the heat exchanger is connected to the water supply pump through the water supply pipeline, and the steam-water separator is connected to the superheater and the flash tank respectively through pipelines; a superheater is provided at the lower part of the convection section, and a chimney is provided at the upper part; the radiation section and the convection section are connected to the heat exchanger respectively through pipelines. The invention has novel structure, reasonable design and reliable operation, and can be used to produce superheated steam with high dryness and high temperature, thereby improving the effect of heavy oil SAGD thermal recovery process.

[0009] Publication (announcement) number: CN202660522U, publication (announcement) date: 2013-01-09 relates to a high-dryness oilfield steam injection boiler, belonging to the technical field of oilfield steam injection boilers; it includes a dual feedwater pump, a heat exchanger, a steam-water separator and a boiler; the boiler includes a transition flue, a convection evaporation section, a secondary convection section, a primary convection section and a chimney; the transition flue, the convection evaporation section, the secondary convection section, the primary convection section and the chimney are fixedly connected together from bottom to top; a burner connected to the transition flue is fixedly connected to the outside of the transition flue; the water outlet of the dual feedwater pump is fixedly connected to the shell side water inlet of the heat exchanger through a first pipeline. The utility model has a reasonable and compact structure and is easy to use. Through the coordinated use of double water feed pumps, a heat exchanger, a burner, a transition flue, a convection evaporation section, a secondary convection section, a primary convection section and a chimney, the purpose of large steam injection volume in a single well and high steam dryness reaching the bottom of the well is achieved, thus meeting the SAGD development process requirements.

[0010] The technical solutions, technical problems to be solved and beneficial effects produced by the above-disclosed technologies are different from the present invention, or are in different technical fields or application scenarios. Regarding more technical features, technical problems to be solved and beneficial effects of the present invention, the above-disclosed technical documents do not contain any technical inspiration. Summary of the invention

[0011] The purpose of the present invention is to provide an oilfield gas steam injection boiler in view of the above-mentioned defects in the prior art, further design the radiation section of the boiler in sections to solve the risk of overheating of the shell and tube caused by changes in the temperature zone, so that scaling and overheating installation areas are easy to monitor, and design a combination of high-dry section and convection section to reduce the thermal shock of flue gas on the high-dry section bare tube, while effectively improving the steam dryness. The use of a flue gas condenser can further reduce the flue gas temperature, absorb the latent heat of vaporization of water vapor in the flue gas, form condensed water, and increase the boiler efficiency to more than 100%. Through the optimization of the heating surface and the design of the flue structure, the heat exchange ratio of the radiation section and the convection section is optimized to 5:5, and the heat exchange is more in line with the heat release characteristics of the natural gas flame. The tail flue gas resistance is reduced by three different forms of pressure reduction during the flue gas flow.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] An oilfield gas steam injection boiler comprises a radiation section, a convection section and a condensation section, wherein the convection section is provided with convection section bare tubes and convection section finned tubes, a high dry section is added between the convection section bare tubes and the convection section finned tubes, and the high dry section is provided with high dry section bare tubes and high dry section finned tubes, and the flue gas passes through the radiation section, the convection section bare tubes, the high dry section bare tubes, the high dry section finned tubes, the convection section finned tubes and the condensation section heat exchange bare tubes in sequence.

[0014] Furthermore, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section, and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area, a flue gas effect area, and a flue gas condensation negative pressure area, that is, the connection between the radiation section and the convection section is a reduced diameter channel, and the reduced diameter channel is the flue gas nozzle effect area. The flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area. The flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney.

[0015] Furthermore, it also includes a water tank, and the water supply of the water tank passes through the condensation section heat exchange light tube, deaerator, convection section fin tube, convection section light tube, high dry section light tube, high dry section fin tube, and the steam injection pipe of the boiler steam outlet in sequence.

[0016] Furthermore, a softener is arranged on the connecting water path between the water tank and the heat exchange light pipe of the condensation section.

[0017] Furthermore, a plunger pump is provided on the connecting water path between the deaerator and the convection section light pipe.

[0018] Furthermore, the condensation section is provided with a condensation baffle, which is located below the heat exchange light pipe of the condensation section. The condensation baffle is also located above the light pipe of the convection section. The condensation baffle is provided with a water receiving trough, and the edge of the water receiving trough has a drain outlet, which is connected to a recovery tank through a pipeline, and the recovery tank is connected to a water tank through a condensed water recovery pump.

[0019] Furthermore, the water path connecting the convection section fin tubes and the high dry section fin tubes must pass through the radiation section.

[0020] Furthermore, the radiation section adopts a single horizontal serpentine water-cooled wall to form a cylindrical furnace in the middle; a flue gas baffle is set at the connection between the convection section and the radiation section to reduce the flow cross-sectional area, forming a flue gas nozzle effect zone; the condensation section exchanges heat through flue gas condensation, water vapor in the flue gas condenses, and the flue gas volume shrinks to form a negative pressure zone; the flue gas temperature at the condensation section outlet is higher than the chimney outlet air, and the thermal pressure forms a chimney effect zone, and the entire tail flue above the condensation section forms a negative pressure suction environment.

[0021] Furthermore, a radiation-convection heat transfer ratio of 5:5 is adopted.

[0022] On the other hand, in order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0023] An oilfield gas-fired steam injection boiler comprises a radiation section, a convection section and a condensation section arranged along a flue gas flow direction, wherein the convection section is provided with a convection section bare tube and a convection section fin tube, a high dry section is added between the convection section bare tube and the convection section fin tube, the high dry section is provided with a high dry section bare tube and a high dry section fin tube, and the flue gas passes through the radiation section, the convection section bare tube, the high dry section bare tube, the high dry section fin tube, the convection section fin tube and the condensation section heat exchange bare tube in sequence.

[0024] Furthermore, the radiation section includes a radiation high-temperature section and a radiation low-temperature section arranged along the direction of flue gas flow, and the radiation section is provided with a radiation high-temperature section light pipe located in the radiation high-temperature section and a radiation low-temperature section light pipe located in the radiation low-temperature section, and the heat exchange medium flows through the radiation high-temperature section light pipe and the radiation low-temperature section light pipe in sequence.

[0025] Furthermore, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area, a flue gas effect area and a flue gas condensation negative pressure area. A reduced diameter channel is provided at the connection between the radiation section and the convection section, and the reduced diameter channel is the flue gas nozzle effect area. The flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area. The flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney.

[0026] Furthermore, it also includes a water tank, and the water supply of the water tank passes through the condensation section heat exchange light tube, deaerator, convection section fin tube, convection section light tube, high dry section light tube, high dry section fin tube, and the steam injection pipe of the boiler steam outlet in sequence.

[0027] Furthermore, a softener is arranged on the connecting water path between the water tank and the heat exchange light pipe of the condensation section.

[0028] Furthermore, a plunger pump is provided on the connecting water path between the deaerator and the convection section light pipe.

[0029] Furthermore, the condensation section is provided with a condensation baffle, which is located below the heat exchange light pipe of the condensation section. The condensation baffle is also located above the light pipe of the convection section. The condensation baffle is provided with a water receiving trough, and a drain outlet is provided at the edge of the water receiving trough. The drain outlet is connected to a recovery tank through a pipeline, and the recovery tank is connected to a water tank through a condensed water recovery pump.

[0030] Furthermore, the water path connecting the convection section fin tubes and the high dry section fin tubes must pass through the radiation section.

[0031] Furthermore, the radiation high-temperature section adopts a single horizontal serpentine water-cooled wall, forming a cylindrical furnace in the middle; the radiation low-temperature section adopts a single horizontal serpentine water-cooled wall, forming a cylindrical furnace in the middle; the convection section and the radiation section are connected by setting a flue gas baffle to reduce the flow cross-sectional area to form a flue gas nozzle effect zone; the condensation section exchanges heat through flue gas condensation, water vapor in the flue gas condenses, and the flue gas volume shrinks to form a negative pressure zone; the outlet of the condensation section is connected to the tail chimney, and the internal flue of the tail chimney forms a flue gas thermal pressure chimney effect zone to form a negative pressure suction environment.

[0032] Furthermore, a radiation-convection heat transfer ratio of 5:5 is adopted.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. Design a combination of high-dry section and convection section to reduce the thermal shock of flue gas on the high-dry section bare pipe and effectively improve the steam dryness.

[0035] 2. The use of flue gas condenser can further reduce the flue gas temperature, absorb the latent heat of vaporization of water vapor in the flue gas, form condensed water, and increase the boiler efficiency to more than 100%.

[0036] 3. Through the optimization of the heating surface and the design of the flue structure, the heat exchange ratio of the radiation section and the convection section is optimized to 5:5, and the heat exchange is more in line with the heat release characteristics of natural gas flames.

[0037] 4. Reduce tail gas resistance by reducing pressure in three different forms during the flue gas flow.

[0038] 5. Improve the water quality by combining feed water preheating with flue gas condensation.

[0039] 6. Reduce the axial length of the radiation section and the height of the flue gas outlet from the ground to ensure the flexible transportation of the steam injection boiler at all steam well sites. The overall boiler size is shortened by 2-3 meters, which reduces the weight of the steam injection boiler and facilitates the transportation of the steam injection boiler.

[0040] 7. The zoning setting of the radiation section can set tube shells of different materials according to the flame temperature to solve the risk of tube shell overheating caused by the change of flame temperature zone of the low-nitrogen burner; secondly, the zoning setting can more easily realize the uniform heat exchange control of the water-cooled wall; thirdly, the zoning setting, the steam zone in the high-temperature and low-temperature zone tubes is moved back as a whole, and the scaling and over-temperature safety occurrence area is easier to monitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic structural diagram of an oilfield gas steam injection boiler according to an embodiment of the present invention;

[0042] Figure 2 It is a longitudinal section view of various sections;

[0043] Figure 3 This is a schematic structural diagram of an oilfield gas steam injection boiler according to another embodiment of the present invention.

[0044] Explanation of the reference numerals: radiation section 1, convection section 2, high-dry section 3, condensation baffle 5, condensation section 4, recovery tank 6, condensate recovery pump 7, water tank 8, softener 9, deaerator 10, plunger pump 11, flue gas nozzle effect zone 12, flue gas effect zone 13, flue gas condensation negative pressure zone 14, flue gas hot pressure chimney effect zone 15, radiation high temperature section 16, radiation low temperature section 17, radiation high temperature section light pipe 18, radiation low temperature section light pipe 19, convection section light pipe 21, high-dry section light pipe 31, high-dry section fin tube 32, convection section fin tube 22, condensation section heat exchange light pipe 41. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Embodiment 1:

[0047] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0048] An oilfield gas steam injection boiler comprises a radiation section 1, a convection section 2, and a condensation section 4. The convection section is provided with a convection section bare tube 21 and a convection section fin tube 22. A high dry section 3 is added between the convection section bare tube and the convection section fin tube. The high dry section is provided with a high dry section bare tube 31 and a high dry section fin tube 32. The flue gas passes through the radiation section, the convection section bare tube, the high dry section bare tube, the high dry section fin tube, the convection section fin tube, and the condensation section heat exchange bare tube 41 in sequence.

[0049] Furthermore, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area 12, a flue gas effect area 13, and a flue gas condensation negative pressure area 14, that is, the connection between the radiation section and the convection section is a reduced diameter channel, and the reduced diameter channel is the flue gas nozzle effect area 12. The flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area. The flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney, and the chimney above the condensation section is the flue gas thermal pressure chimney effect area 15.

[0050] Furthermore, it also includes a water tank 8, and the water supply of the water tank passes through the condensing section heat exchange light pipe, the deaerator 10, the convection section finned tube, the convection section light pipe, the high dry section light pipe, the high dry section finned tube, and the steam injection pipe of the boiler steam outlet in sequence. The water outlet temperature of the water tank is 25 degrees at room temperature. The medium temperature in the connecting water path between the convection section light pipe and the convection section finned tube is 254 degrees. The medium temperature in the steam injection pipe of the boiler steam outlet is 369 degrees, and the dryness is 90%.

[0051] Furthermore, a softener 9 is provided on the connecting water path between the water tank and the heat exchange light pipe of the condensation section.

[0052] Furthermore, a plunger pump 11 is provided on the connecting waterway between the deaerator and the convection section light pipe. The medium temperature in this section of the waterway is 60 degrees.

[0053] Furthermore, the condensation section is provided with a condensation baffle, which is located below the heat exchange light pipe of the condensation section. The condensation baffle is also located above the light pipe of the convection section. The condensation baffle is provided with a water receiving trough, and the edge of the water receiving trough has a drain outlet, which is connected to the recovery tank 6 through a pipeline, and the recovery tank is connected to the water tank through a condensed water recovery pump 7.

[0054] Furthermore, the water path connecting the finned tubes of the convection section and the finned tubes of the high-dry section must pass through the radiation section, and the temperature of the medium in this water path is 325 degrees.

[0055] Furthermore, the radiation section adopts a single horizontal serpentine water-cooled wall to form a cylindrical furnace in the middle; a flue gas baffle is set at the connection between the convection section and the radiation section to reduce the flow cross-sectional area to form a flue gas nozzle effect zone; the condensation section exchanges heat through flue gas condensation, water vapor in the flue gas condenses, and the flue gas volume shrinks to form a negative pressure zone; the flue gas temperature at the condensation section outlet is higher than that at the chimney outlet, and the flue gas temperature entering the chimney is 56 degrees, and the thermal pressure forms a chimney effect zone, and the entire tail flue above the condensation section forms a negative pressure suction environment.

[0056] Furthermore, a radiation-convection heat transfer ratio of 5:5 is adopted.

[0057] Combination Figure 1 It can be seen that the implementation method of the present invention is: the new type of oil field high-efficiency gas injection steam boiler includes a radiation section, a convection section, a high-dry section and a condensation section; wherein the flue gas flow direction is the radiation section, the convection section light pipe, the high-dry section light pipe, the high-dry section fin tube, the convection section fin tube, and the condensation section light pipe. The high-dry section is installed between the convection section light pipe area and the convection section fin tube area, and is arranged along the axial direction of the radiation section. The condensation section is located directly above the flue gas effect area.

[0058] The core idea of ​​the implementation scheme described in the present invention is: using a flue gas condenser to further reduce the flue gas temperature, absorb the latent heat of vaporization of water vapor in the flue gas, form condensed water, and improve the boiler efficiency to more than 100%; through the optimization of the heating surface and the design of the flue structure, the heat exchange ratio of the radiation section and the convection section is optimized to 5:5, and the heat exchange is more in line with the heat release characteristics of the natural gas flame; through three different forms of pressure reduction during the flue gas flow process, the tail flue gas resistance is reduced; through the combination of feed water preheating and flue gas condensation, the feed water quality is improved. At the same time, the overall boiler size is shortened by 2-3 meters, which reduces the weight of the steam injection boiler and is conducive to the transportation of the steam injection boiler.

[0059] The present invention arranges the high dry section between the convection section bare tube area and the fin tube area, and reduces the thermal shock of flue gas on the high dry section bare tube through the low temperature water in the convection section bare tube area pipe path, while effectively improving the steam dryness.

[0060] The present invention uses a flue gas condenser to further reduce the flue gas temperature, absorb the vaporization latent heat of water vapor in the flue gas, form condensed water, and improve the boiler efficiency to more than 100%. At the same time, the flue gas volume shrinks after the flue gas is condensed, reducing the flue gas flow resistance.

[0061] The present invention optimizes the heat exchange ratio of the radiation section and the convection section to 5:5 through the optimization of the heating surface and the design of the flue structure, and the heat exchange is more in line with the heat release characteristics of the natural gas flame. At the same time, the tail flue gas resistance is reduced by three different forms of pressure reduction during the flue gas flow process.

[0062] The present invention improves the quality of feed water by combining feed water preheating with flue gas condensation. At the same time, the overall boiler size is shortened by 2-3 meters, the weight of the steam injection boiler is reduced, and the transportation of the steam injection boiler is facilitated.

[0063] The core points of the present invention include four aspects: heat exchange ratio balance design, flue resistance reduction structure design, flue gas condensation waste heat recovery design and flue gas preheating water deoxygenation design.

[0064] Balanced heat exchange ratio design Based on the characteristics of short combustion flame and small heat radiation of gas-fired steam-injected boilers, the heat exchange ratio of convection section and radiation section is readjusted. The heat exchange surface is arranged in the order of radiation section, convection section light tube, high dry section light tube, high dry section fin tube, convection section fin tube, condensation section light tube along the direction of flue gas flow. High-efficiency high-dry gas boilers change the ratio of radiation and convection heat absorption of conventional boilers to 6:4, and adopt a ratio of radiation convection heat exchange of 5:5, which is more suitable for the combustion characteristics of gas boilers, and the entire heat exchange process on the flue gas side is more reasonable and efficient.

[0065] The design of the flue resistance reduction structure includes the flue gas passing through the flue gas nozzle effect area at the tail of the convection section fin tube, the flue gas effect area, the flue gas negative pressure area at the condensation section, and the chimney effect area formed by the heat pressure at the flue gas outlet. Under the condition that the total heat exchange area increases by 100 square meters, the flue resistance remains unchanged. The flue gas temperature at the condensation section outlet is higher than the air at the chimney outlet, and the heat pressure forms the chimney effect area. The entire tail flue forms a negative pressure suction environment to reduce the flue gas flow resistance.

[0066] The flue gas condensation waste heat recovery design adds a condensation section heat exchange light tube at the end of the condensation section, and uses the flue gas to cool down to below 55°C through the shell side. 90% of the steam in the natural gas flue gas forms condensed water, realizing flue gas latent heat recovery, and the boiler thermal efficiency is greater than 100%.

[0067] The flue gas preheating feed water deoxygenation design passes the softener outlet water into the flue gas condensation heat exchange zone pipe. After heat exchange with the flue gas, the feed water temperature rises by about 20°C, changes the oxygen partial pressure entering the vacuum deaerator, improves the boiler feed water deoxygenation effect, and the feed water no longer needs to be added to meet the operating conditions. The feed water steam process is recycled, and the feed water is heated, deoxygenated, steam is formed, and reheated to produce a high-dryness steam process layout.

[0068] Embodiment 2:

[0069] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0070] An oilfield gas steam injection boiler comprises a radiation section 1, a convection section 2, and a condensation section 4. The convection section is provided with a convection section bare tube 21 and a convection section fin tube 22. A high dry section 3 is added between the convection section bare tube and the convection section fin tube. The high dry section is provided with a high dry section bare tube 31 and a high dry section fin tube 32. The flue gas passes through the radiation section, the convection section bare tube, the high dry section bare tube, the high dry section fin tube, the convection section fin tube, and the condensation section heat exchange bare tube 41 in sequence.

[0071] Furthermore, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area 12, a flue gas effect area 13, and a flue gas condensation negative pressure area 14, that is, the connection between the radiation section and the convection section is a reduced diameter channel, and the reduced diameter channel is the flue gas nozzle effect area 12. The flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area. The flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney, and the chimney above the condensation section is the flue gas thermal pressure chimney effect area 15.

[0072] Furthermore, it also includes a water tank 8, and the water supply of the water tank passes through the condensing section heat exchange light pipe, the deaerator 10, the convection section finned tube, the convection section light pipe, the high dry section light pipe, the high dry section finned tube, and the steam injection pipe of the boiler steam outlet in sequence. The water outlet temperature of the water tank is 25 degrees at room temperature. The medium temperature in the connecting water path between the convection section light pipe and the convection section finned tube is 254 degrees. The medium temperature in the steam injection pipe of the boiler steam outlet is 369 degrees, and the dryness is 90%.

[0073] Furthermore, a softener 9 is provided on the connecting water path between the water tank and the heat exchange light pipe of the condensation section.

[0074] Furthermore, a plunger pump 11 is provided on the connecting waterway between the deaerator and the convection section light pipe. The medium temperature in this section of the waterway is 60 degrees.

[0075] Furthermore, the condensation section is provided with a condensation baffle, which is located below the heat exchange light pipe of the condensation section. The condensation baffle is also located above the light pipe of the convection section. The condensation baffle is provided with a water receiving trough, and the edge of the water receiving trough has a drain outlet, which is connected to the recovery tank 6 through a pipeline, and the recovery tank is connected to the water tank through a condensed water recovery pump 7.

[0076] Embodiment 3:

[0077] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0078] An oilfield gas steam injection boiler comprises a radiation section 1, a convection section 2, and a condensation section 4. The convection section is provided with a convection section bare tube 21 and a convection section fin tube 22. A high dry section 3 is added between the convection section bare tube and the convection section fin tube. The high dry section is provided with a high dry section bare tube 31 and a high dry section fin tube 32. The flue gas passes through the radiation section, the convection section bare tube, the high dry section bare tube, the high dry section fin tube, the convection section fin tube, and the condensation section heat exchange bare tube 41 in sequence.

[0079] Furthermore, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area 12, a flue gas effect area 13, and a flue gas condensation negative pressure area 14, that is, the connection between the radiation section and the convection section is a reduced diameter channel, and the reduced diameter channel is the flue gas nozzle effect area 12. The flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area. The flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney, and the chimney above the condensation section is the flue gas thermal pressure chimney effect area 15.

[0080] Furthermore, it also includes a water tank 8, and the water supply of the water tank passes through the condensing section heat exchange light pipe, the deaerator 10, the convection section finned tube, the convection section light pipe, the high dry section light pipe, the high dry section finned tube, and the steam injection pipe of the boiler steam outlet in sequence. The water outlet temperature of the water tank is 25 degrees at room temperature. The medium temperature in the connecting water path between the convection section light pipe and the convection section finned tube is 254 degrees. The medium temperature in the steam injection pipe of the boiler steam outlet is 369 degrees, and the dryness is 90%.

[0081] Embodiment 4:

[0082] See also Figures 2 to 3 , the present invention provides a technical solution:

[0083] An oilfield gas-fired steam injection boiler comprises a radiation section 1, a convection section 2 and a condensation section 4 arranged along a flue gas flow direction, the convection section 2 is provided with a convection section bare tube 21 and a convection section fin tube 22, a high dry section 3 is added between the convection section bare tube and the convection section fin tube, the high dry section is provided with a high dry section bare tube 32 and a high dry section fin tube 31, and the flue gas passes through the radiation section, the convection section bare tube, the high dry section bare tube, the high dry section fin tube, the convection section fin tube and the condensation section heat exchange bare tube 41 in sequence.

[0084] In addition, the radiation section 1 includes a radiation high-temperature section 16 and a radiation low-temperature section 17 arranged along the direction of flue gas flow. The radiation section is provided with a radiation high-temperature section light pipe 18 located in the radiation high-temperature section 16 and a radiation low-temperature section light pipe 19 located in the radiation low-temperature section 17. The heat exchange medium flows through the radiation high-temperature section light pipe 18 and the radiation low-temperature section light pipe 19 in turn, and the flue gas passes through the radiation high-temperature section light pipe 18 and the radiation low-temperature section light pipe 19 in turn.

[0085] like Figure 3 As shown, in the radiation section 1, the flue gas flows through the radiation high temperature section 16 and the radiation low temperature section 17 in sequence, that is, reaches the radiation high temperature section light pipe 18 and the radiation low temperature section light pipe 19 in sequence; the heat exchange medium, such as the water in the water tank described below, passes through the radiation high temperature section light pipe 18 and the radiation low temperature section light pipe 19 in sequence to absorb the heat energy in the radiation section 1; accordingly, according to the time of absorbing heat energy, the temperature of the heat exchange medium in the radiation high temperature section light pipe 18 is relatively lower than the temperature of the heat exchange medium in the radiation low temperature section light pipe 19, wherein, when the heat exchange medium is water, the radiation high temperature section light pipe 18 can be positioned in the radiation section 1 so that the water therein is less than or equal to the critical temperature of vaporization, and no water vapor appears in the radiation high temperature section light pipe 18, and the radiation low temperature section 19 is positioned so that the water therein continues to absorb heat to form water vapor, that is, the light pipes in which water vapor begins to be formed are concentrated at the downstream position of the radiation section 1, and the salt precipitation and scaling caused by the formation of water vapor are concentrated in the light pipes at the downstream position of the radiation section 1, which is convenient for monitoring the scaling of this part of the light pipes and for maintaining the scaled light pipes.

[0086] The setting of the radiation high temperature section 16 and the radiation low temperature section 17, that is, the selection of the respective areas where the radiation high temperature section light pipe 18 and the radiation low temperature section light pipe 19 are located, needs to be based on the endothermic evaporation of water. According to the specific boiler structure and related calculations, the radiation high temperature section light pipe 18 and the radiation low temperature section light pipe 19 are set in appropriate areas, so that the water entering the radiation high temperature section light pipe 18 will not evaporate to form steam (below the critical temperature of evaporation), but only form steam in the radiation low temperature section light pipe 19. In short, the division of the radiation high temperature section 16 and the radiation low temperature section 17 is based on the state of water flowing through the radiation high temperature section light pipe 18 and the radiation low temperature section light pipe 19 (whether steam is formed).

[0087] refer to Figure 3 , which simply shows the arrangement of the radiation high temperature section light pipe 18 and the radiation low temperature section light pipe 19, is intended to illustrate that the heat exchange medium first absorbs heat energy in the radiation high temperature section 16, and then enters the radiation low temperature section 17 to absorb heat energy, and does not reciprocate and cross flow between the radiation high temperature section 16 and the radiation low temperature section 17.

[0088] Furthermore, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area 12, a flue gas effect area 13, and a flue gas condensation negative pressure area 14, that is, a reduced diameter channel is provided at the connection between the radiation section and the convection section, and the reduced diameter channel is the flue gas nozzle effect area 12, and the flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area, the flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney, and the chimney above the condensation section is the flue gas thermal pressure chimney effect area 15.

[0089] Furthermore, it also includes a water tank 8, and the water supply of the water tank passes through the condensing section heat exchange light pipe, the deaerator 10, the convection section finned tube, the convection section light pipe, the high dry section light pipe, the high dry section finned tube, and the steam injection pipe of the boiler steam outlet in sequence. The water outlet temperature of the water tank is 25 degrees at room temperature. The medium temperature in the connecting water path between the convection section light pipe and the convection section finned tube is 254 degrees. The medium temperature in the steam injection pipe of the boiler steam outlet is 369 degrees, and the dryness is 90%.

[0090] Furthermore, a softener 9 is provided on the connecting water path between the water tank and the heat exchange light pipe of the condensation section.

[0091] Furthermore, a plunger pump 11 is provided on the connecting waterway between the deaerator and the convection section light pipe. The medium temperature in this section of the waterway is 60 degrees.

[0092] Furthermore, the condensation section is provided with a condensation baffle, which is located below the heat exchange light pipe of the condensation section. The condensation baffle is also located above the light pipe of the convection section. The condensation baffle is provided with a water receiving trough, and the edge of the water receiving trough has a drain outlet, which is connected to the recovery tank 6 through a pipeline, and the recovery tank is connected to the water tank through a condensed water recovery pump 7.

[0093] Furthermore, the water path connecting the convection section fin tubes and the high-dry section fin tubes passes through the radiation section, and the medium temperature in this water path is 325 degrees. That is, the water path passes through the radiation high-temperature section light tube 18 and the radiation low-temperature section light tube 19 in sequence.

[0094] Furthermore, the radiation high-temperature section 16 adopts a single horizontal serpentine water-cooled wall, forming a cylindrical furnace in the middle; the radiation low-temperature section 17 adopts a single horizontal serpentine water-cooled wall, forming a cylindrical furnace in the middle; the convection section and the radiation section are connected by setting a flue gas baffle to reduce the flow cross-sectional area to form a flue gas nozzle effect zone; the condensation section exchanges heat through flue gas condensation, water vapor in the flue gas condenses, and the flue gas volume shrinks to form a negative pressure zone; the outlet of the condensation section is connected to the tail chimney, and the internal flue of the tail chimney forms a flue gas thermal pressure chimney effect zone to form a negative pressure suction environment, wherein the flue gas temperature entering the tail chimney is 56 degrees.

[0095] Furthermore, a radiation-convection heat transfer ratio of 5:5 is adopted.

[0096] Combination Figure 3 It can be seen that the implementation method of the present invention is as follows: the new type of oilfield high-efficiency gas-fired steam injection boiler includes a radiation section, a convection section, a high-dry section and a condensation section. The radiation section includes a radiation high-temperature section 16 and a radiation low-temperature section 17 arranged along the flow direction of the flue gas. The radiation section is provided with a radiation high-temperature section light pipe 18 located in the radiation high-temperature section 16 and a radiation low-temperature section light pipe 19 located in the radiation low-temperature section 17; wherein the flow direction of the flue gas is, in order, the radiation high-temperature section light pipe 18, the radiation low-temperature section light pipe 19, the convection section light pipe, the high-dry section light pipe, the high-dry section fin tube, the convection section fin tube, and the condensation section light pipe. The high-dry section is installed in the middle of the convection section light pipe area and the convection section fin tube area, and is arranged along the axial direction of the radiation section. The condensation section is located directly above the flue gas effect zone.

[0097] The core idea of ​​the implementation scheme of the present invention is: the radiation section is divided into a radiation high temperature section 16 upstream of the flue gas flow direction and a radiation low temperature section 17 downstream, and the radiation high temperature section light tube 18 and the radiation low temperature section light tube 19 are respectively in different temperature areas, so that the heat exchange of the water-cooled wall is easier to control, and the low temperature area of ​​the heat exchange fluid in the tube is concentrated in the upstream and the high temperature area is concentrated in the downstream, which is more convenient to monitor the scaling and over-temperature safety areas, and different tube shell materials can be used according to the different flue gas and flame temperatures; the flue gas condenser is used to further reduce the flue gas temperature, absorb the latent heat of vaporization of water vapor in the flue gas, form condensed water, and improve the boiler efficiency to more than 100%; through the optimization of the heating surface and the design of the flue structure, the heat exchange ratio of the radiation section and the convection section is optimized to 5:5, and the heat exchange is more in line with the heat release characteristics of the natural gas flame; through three different forms of pressure reduction during the flue gas flow process, the tail flue gas resistance is reduced; through the combination of feed water preheating and flue gas condensation, the feed water quality is improved. At the same time, the overall boiler size is shortened by 2-3 meters, the weight of the steam injection boiler is reduced, which is conducive to the transportation of the steam injection boiler.

[0098] The present invention arranges the high dry section between the convection section bare tube area and the fin tube area, and reduces the thermal shock of flue gas on the high dry section bare tube through the low temperature water in the convection section bare tube area pipe path, while effectively improving the steam dryness.

[0099] The present invention uses a flue gas condenser to further reduce the flue gas temperature, absorb the vaporization latent heat of water vapor in the flue gas, form condensed water, and improve the boiler efficiency to more than 100%. At the same time, the flue gas volume shrinks after the flue gas is condensed, reducing the flue gas flow resistance.

[0100] The present invention optimizes the heat exchange ratio of the radiation section and the convection section to 5:5 through the optimization of the heating surface and the design of the flue structure, and the heat exchange is more in line with the heat release characteristics of the natural gas flame. At the same time, the tail flue gas resistance is reduced by three different forms of pressure reduction during the flue gas flow process.

[0101] The present invention improves the quality of feed water by combining feed water preheating with flue gas condensation. At the same time, the overall boiler size is shortened by 2-3 meters, the weight of the steam injection boiler is reduced, and the transportation of the steam injection boiler is facilitated.

[0102] The core points of the present invention include four aspects: heat exchange ratio balance design, flue resistance reduction structure design, flue gas condensation waste heat recovery design and flue gas preheating water deoxygenation design.

[0103] Balanced heat exchange ratio design Based on the characteristics of short combustion flame and small heat radiation of gas-fired steam-injected boilers, the heat exchange ratio of convection section and radiation section is readjusted. The heat exchange surface is arranged in the order of radiation section, convection section light tube, high dry section light tube, high dry section fin tube, convection section fin tube, condensation section light tube along the direction of flue gas flow. High-efficiency high-dry gas boilers change the ratio of radiation and convection heat absorption of conventional boilers to 6:4, and adopt a ratio of radiation convection heat exchange of 5:5, which is more suitable for the combustion characteristics of gas boilers, and the entire heat exchange process on the flue gas side is more reasonable and efficient.

[0104] The design of the flue resistance reduction structure includes the flue gas passing through the flue gas nozzle effect area at the tail of the convection section fin tube, the flue gas effect area, the flue gas negative pressure area at the condensation section, and the chimney effect area formed by the heat pressure at the flue gas outlet. Under the condition that the total heat exchange area increases by 100 square meters, the flue resistance remains unchanged. The flue gas temperature at the condensation section outlet is higher than the air at the chimney outlet, and the heat pressure forms the chimney effect area. The entire tail flue forms a negative pressure suction environment to reduce the flue gas flow resistance.

[0105] The flue gas condensation waste heat recovery design adds a condensation section heat exchange light tube at the end of the condensation section, and uses the flue gas to cool down to below 55°C through the shell side. 90% of the steam in the natural gas flue gas forms condensed water, realizing flue gas latent heat recovery, and the boiler thermal efficiency is greater than 100%.

[0106] The flue gas preheating feed water deoxygenation design passes the softener outlet water into the flue gas condensation heat exchange zone pipe. After heat exchange with the flue gas, the feed water temperature rises by about 20°C, changes the oxygen partial pressure entering the vacuum deaerator, improves the boiler feed water deoxygenation effect, and the feed water no longer needs to be added to meet the operating conditions. The feed water steam process is recycled, and the feed water is heated, deoxygenated, steam is formed, and reheated to produce a high-dryness steam process layout.

[0107] Although all the above embodiments use Figures 1 to 3 However, as a person skilled in the art can clearly know, there is no need to provide a separate drawing to represent, as long as the missing parts or structural features in the embodiment are removed from the drawing. This is clear to those skilled in the art. Of course, the embodiment with more parts is only the optimal embodiment, and the embodiment with fewer parts is the basic embodiment, but it can also achieve the basic purpose of the invention, so all of them are within the scope of protection of the present invention.

[0108] All parts and components not discussed in detail in this application and the connection methods of the parts and components in this application belong to the well-known technology in this technical field and will not be described in detail, such as welding, threaded connection, etc.

[0109] In the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0110] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0111] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An oilfield gas-fired steam injection boiler, comprising a radiation section, a convection section, and a condensation section arranged along the flue gas flow direction, characterized in that: The convection section is provided with a convection section light tube and a convection section fin tube, a high dry section is added between the convection section light tube and the convection section fin tube, the high dry section is provided with a high dry section light tube and a high dry section fin tube, and the flue gas passes through the radiation section, the convection section light tube, the high dry section light tube, the high dry section fin tube, the convection section fin tube, and the condensation section heat exchange light tube in sequence; Wherein, the radiation section includes a radiation high temperature section and a radiation low temperature section arranged along the flow direction of the flue gas, and the radiation section is provided with a radiation high temperature section light pipe located in the radiation high temperature section and a radiation low temperature section light pipe located in the radiation low temperature section, and the heat exchange medium flows through the radiation high temperature section light pipe and the radiation low temperature section light pipe in sequence; Among them, the channel structure formed by the outer shells of the radiation section, convection section, high-dry section and condensation section is a flue resistance reduction structural area, and the flue resistance reduction structural area includes a flue gas nozzle effect area, a flue gas effect area and a flue gas condensation negative pressure area. A reduced diameter channel is arranged at the connection between the radiation section and the convection section, and the reduced diameter channel is the flue gas nozzle effect area. The flow cross-sectional area of ​​the reduced diameter channel is smaller than the flow cross-sectional area of ​​the radiation section and the convection section at the same time. The outer shell where the convection section and the high-dry section are located is the flue gas effect area, and the outer shell where the condensation section is located is the flue gas condensation negative pressure area. The flow cross-sectional area at the connection between the lower port of the condensation section and the upper port of the convection section is larger than the flow cross-sectional area at the connection between the upper port of the condensation section and the chimney.

2. The oilfield gas steam injection boiler according to claim 1, characterized in that: It also includes a water tank, and the water supply of the water tank passes through the condensation section heat exchange light tube, the deaerator, the convection section fin tube, the convection section light tube, the high-dry section light tube, the high-dry section fin tube, and the steam injection pipeline of the boiler steam outlet in sequence.

3. The oilfield gas steam injection boiler according to claim 2, characterized in that: A softener is arranged on the connecting water path between the water tank and the heat exchange light pipe of the condensation section.

4. The oilfield gas steam injection boiler according to claim 3, characterized in that: A plunger pump is arranged on the connecting water path between the deaerator and the convection section light pipe.

5. The oilfield gas steam injection boiler according to claim 2, characterized in that: The condensation section is provided with a condensation baffle, which is located below the heat exchange light pipe of the condensation section. The condensation baffle is also located above the light pipe of the convection section. The condensation baffle is provided with a water receiving trough, and the edge of the water receiving trough has a drain port, which is connected to a recovery tank through a pipeline, and the recovery tank is connected to a water tank through a condensed water recovery pump.

6. The oilfield high-efficiency gas-fired steam injection boiler according to claim 2, characterized in that: The water path connecting the convection section fin tubes and the high dry section fin tubes passes through the radiation section.

7. The oilfield gas steam injection boiler according to claim 1, 3, 4 or 5, characterized in that: The radiation high temperature section adopts a single horizontal serpentine water-cooled wall, forming a cylindrical furnace in the middle; the radiation low temperature section adopts a single horizontal serpentine water-cooled wall, forming a cylindrical furnace in the middle; A flue gas baffle is set at the connection between the convection section and the radiation section to reduce the flow cross-sectional area, forming a flue gas nozzle effect zone; the condensation section exchanges heat through flue gas condensation, water vapor in the flue gas condenses, and the flue gas volume shrinks to form a negative pressure zone; the outlet of the condensation section is connected to the tail chimney, and the internal flue of the tail chimney forms a flue gas thermal pressure chimney effect zone to form a negative pressure suction environment.

8. The oilfield gas steam injection boiler according to claim 1, 3, 4 or 5, characterized in that: A 5:5 ratio of radiation and convection heat transfer is adopted.

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