A steam generator for burning bio-pellet fuel

Abstract

This invention provides a steam generator for burning biomass pellet fuel. By optimizing the multi-pass heat exchange process of feedwater and heated flue gas, it achieves efficient thermal energy utilization and improved steam quality. Within the steam generator, feedwater sequentially undergoes radiative heat exchange in the combustion chamber, convective heat exchange in the jacket, and convective heat exchange outside the water pipes, gradually absorbing heat and vaporizing to continuously generate wet steam. This wet steam enters the steam collector and is further heated by the heated flue gas, increasing its dryness and meeting industrial demands for high-quality steam. Therefore, this biomass pellet fuel steam generator rationally utilizes the heat from the heated flue gas, improving heat exchange efficiency while reducing heat waste and increasing fuel utilization. Furthermore, the optimized heat exchange path avoids localized overheating or thermal efficiency loss, ensuring stability and uniformity, resulting in significant energy-saving and environmentally friendly effects, meeting the requirements of efficient and environmentally friendly applications.

Description

Technical Field

[0001] This utility model relates to the field of steam generator technology, specifically a steam generator for burning biomass pellet fuel. Background Technology

[0002] Steam generators are widely used in industrial production, heating, medical care, and food processing. They heat water to produce high-temperature steam through fuel combustion or other forms of energy conversion. Existing steam generators are mainly classified into biomass fuel steam generators, electric steam generators, and oil / gas fuel steam generators. Among these, biomass fuel steam generators have gained increasing popularity in recent years due to their low fuel cost, wide availability, and good environmental performance.

[0003] However, despite the significant advantages of biomass pellet steam generators in terms of environmental protection and economy, some traditional biomass pellet steam generators often face problems such as low combustion efficiency and insufficient heat exchange. These problems not only limit the overall thermal energy utilization rate of the steam generator but also lead to unnecessary fuel waste and environmental pollution. Therefore, how to optimize the combustion and heat exchange process of the steam generator and improve the thermal energy conversion efficiency has become a problem that needs to be solved in this field. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a steam generator for burning biomass pellet fuel, aiming to solve the problems of low combustion efficiency and insufficient heat exchange in some existing biomass pellet steam generators.

[0005] A steam generator for burning biomass pellet fuel includes a combustion chamber, a shell, a steam collection box disposed within the shell, and a steam generator body connected to the steam collection box. The steam generator body includes a boiler shell and a furnace liner. The boiler shell is hollow inside and one end is connected to the combustion chamber. The furnace liner is fitted outside the boiler shell, and a water storage cavity is formed between the two. A ring of water pipes is disposed outside the furnace liner, and the two ends of the water pipes are respectively connected to the two ends of the furnace liner along its length and communicate with the cavity. A smoke outlet ring is opened on the side wall of the steam generator body, and the opening of the smoke outlet ring faces the water pipes, so that the heated flue gas generated in the combustion chamber forms a multi-pass heating in the shell.

[0006] Preferably, the combustion chamber is located at the bottom of the steam generator body, and the steam collection box is located at the top of the steam generator body.

[0007] Preferably, a steel fin is provided between each of the water pipes, and the two sides of the steel fin are respectively connected to two adjacent water pipes. The side of the steel fin away from the combustion chamber is connected to the furnace shell.

[0008] Preferably, the adjacent sides of the water pipe are connected, and a notch is provided on the side of the water pipe near the combustion chamber to allow the heated flue gas generated in the combustion chamber to pass through.

[0009] Preferably, the steam collection box includes an outer cylinder and an inner cylinder fitted inside the outer cylinder. A steam chamber is formed between the outer cylinder and the inner cylinder, and the steam chamber is connected to the chamber via a connecting pipe.

[0010] Furthermore, a spiral flow channel is welded into the steam chamber.

[0011] Furthermore, the inner cylinder of the steam collecting box is hollow, and the inner cylinder of the steam collecting box is connected to the boiler shell.

[0012] Preferably, the housing has multiple soot blowing nozzles on the side away from the combustion chamber.

[0013] Preferably, a smoke exhaust port is provided on the side of the housing away from the combustion chamber, and a dust removal and energy-saving device is connected to the smoke exhaust port.

[0014] Preferably, a drain pipe with a valve is provided at the bottom of the main body of the steam generator.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention provides a steam generator for burning biomass pellet fuel. By optimizing the heat exchange process between feedwater and heated flue gas, it achieves efficient thermal energy utilization and improved steam quality. Specifically, feedwater enters the steam generator body through radiative heat exchange via the high-temperature heated flue gas in the combustion chamber, convective heat exchange in the interlayer between the steam generator body and the water pipes, and convective heat exchange on the side of the water pipes away from the steam generator body. During multiple heat exchange cycles, the feedwater within the steam generator body gradually absorbs heat and continuously vaporizes, generating a continuous stream of wet steam. The wet steam then enters the steam collector and completes heat exchange with the rising heated flue gas. Through further heating of the wet steam, the dryness of the steam is significantly improved, meeting industrial application requirements and thus ensuring steam quality to meet the high-quality steam demand in various scenarios. This multi-pass heat exchange design fully utilizes the heat from the heated flue gas generated by combustion, effectively reducing thermal energy waste and improving fuel utilization while ensuring efficient heat exchange. Meanwhile, a well-designed heat exchange path allows the feedwater to gradually heat up and vaporize, avoiding localized overheating or thermal efficiency loss, and ensuring the stability and uniformity of the heat exchange process. Furthermore, by performing a final pass reheating on the wet steam in the steam collector, not only is the steam dryness improved, but the overall system thermal energy utilization rate is also optimized. Therefore, this biomass pellet fuel-fired steam generator achieves high thermal energy utilization efficiency, meeting the technical goals of energy saving and high efficiency, while also considering environmental protection and practicality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the longitudinal section of the biomass pellet fuel described in this utility model;

[0018] Figure 2 This is a schematic diagram of the cross-sectional structure of the main body of the steam generator described in this utility model.

[0019] in:

[0020] 1-Combustion chamber, 2-Boiler shell, 3-Furnace liner, 4-Water pipe, 5-Smoke outlet ring, 6-Connecting pipe, 7-Shell, 8-Outer cylinder of steam collection box, 9-Inner cylinder of steam collection box, 10-Spiral flow channel, 11-Steam generator body, 12-Steam collection box, 13-Soot blowing nozzle, 14-Steel fins. Detailed Implementation

[0021] The embodiments described below are merely some embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0022] Example 1:

[0023] See Figure 1 as well as Figure 2 This embodiment 1 provides a steam generator for burning biomass pellet fuel, comprising a combustion chamber 1, a housing 7, a steam collection box 12 disposed within the housing 7, and a steam generator body 11 connected to the steam collection box 12. Specifically, in this embodiment, the combustion chamber 1 is located at the bottom of the steam generator body 11, and the steam collection box 12 is disposed at the top of the steam generator body 11.

[0024] In this embodiment, the main body 11 of the steam generator includes a pot shell 2 and a furnace liner 3. The pot shell 2 is hollow inside and one end is connected to the combustion chamber 1. The furnace liner 3 is sleeved on the outside of the pot shell 2, and a water storage cavity is formed between the two. A ring of water pipes 4 is provided on the outside of the furnace liner 3, and the two ends of the water pipes 4 are respectively connected to the two ends of the furnace liner 3 along its length and communicate with the cavity. A smoke outlet ring 5 is provided on the side wall of the main body 11 of the steam generator. The opening of the smoke outlet ring 5 faces the water pipes 4, so that the heated flue gas generated by the combustion chamber 1 forms a multi-pass heating in the shell 7.

[0025] Preferably, a steel fin 14 is provided between each of the water pipes 4. The two sides of the steel fin 14 are connected to two adjacent water pipes 4, and the side of the steel fin 14 away from the combustion chamber 1 is connected to the furnace shell 3. Through the steel fin 14, the heated flue gas discharged from the flue gas outlet ring 5 can effectively impact the surface of the water pipes 4, thereby achieving convective heat transfer on the side of the water pipes 4 closest to the steam generator. After the heated flue gas discharged from the flue gas outlet ring 5 reaches the water pipes 4 and the steel fin 14, it moves downwards. Simultaneously, the heated flue gas undergoes a return heat exchange with the water pipes 4 and the water stored in the cavity. When the heated flue gas reaches the bottom, it is blocked by the shell 7 and impacts upwards to enter the next return cycle. Therefore, the combination of the water pipes 4 and the steel fin 14 not only improves the heat exchange efficiency between the heated flue gas and the water pipes 4, but also further enhances the utilization of thermal energy, ensures the uniformity and stability of the heat exchange process, and ultimately improves the overall thermal energy conversion efficiency of the steam generator.

[0026] Specifically, in this embodiment, the steam collecting box 12 includes an outer cylinder 8 and an inner cylinder 9 fitted inside the outer cylinder 8. A steam chamber is formed between the outer cylinder 8 and the inner cylinder 9, and the steam chamber is connected to the inner cylinder through a connecting pipe 6. In this embodiment, the wet steam generated after multiple cycles of heat exchange within the steam generator body 11 smoothly enters the steam chamber through the connecting pipe 6. The combination of the outer cylinder 8 and the inner cylinder 9 effectively improves the efficiency of steam collection and separation, and also facilitates the next cycle of heat exchange between the steam chamber and the heated flue gas, thereby ensuring the quality of the steam and the stable operation of the system.

[0027] More specifically, a spiral flow channel 10 is welded into the steam chamber described in this application. When wet steam enters the steam chamber, it flows along the path of the spiral flow channel 10 and continuously collides with the walls of the outer cylinder 8 of the steam collecting box, the walls of the inner cylinder 9 of the steam collecting box, and the spiral flow channel 10. During this process, the moisture in the wet steam is effectively separated and knocked off, thereby forming high-quality dry steam. Therefore, the spiral flow channel 10 not only increases the contact area and flow path of the wet steam but also enhances the steam separation effect, significantly improves the steam dryness, ensures high-quality steam output, and meets the stringent requirements for dry steam in different scenarios.

[0028] Specifically, the inner cylinder 9 of the steam collecting box described in this application is hollow and is connected to the boiler shell 2. After passing through the main body 11 of the steam generator, some of the heated flue gas generated in the combustion chamber 1 continues to rise and eventually reaches the inner wall of the inner cylinder 9 of the steam collecting box, where it radiates heat to the wet steam in the steam chamber. During this process, the moisture in the wet steam is fully separated, significantly improving the steam quality and outputting high-quality dry steam to meet the industrial demand for dry steam, while maximizing thermal energy utilization efficiency.

[0029] Preferably, the housing 7 has multiple soot blowing nozzles 13 on its side away from the combustion chamber 1. These nozzles 13 periodically inject high-pressure airflow into the steam generator, effectively removing dust and scale adhering to the flue gas during its flow, maintaining surface cleanliness, and thus ensuring the continuity and stability of the steam generator's heat exchange efficiency. Furthermore, the soot blowing nozzles 13 reduce maintenance frequency, improve equipment reliability, and extend the service life of the steam generator.

[0030] Preferably, a flue gas outlet is provided on the side of the housing 7 away from the combustion chamber 1, and a dust collector / energy saver is connected to the flue gas outlet. By installing the dust collector / energy saver, the discharged flue gas can be effectively treated for dust removal, reducing the emission of particulate matter and pollutants, thereby reducing the impact on the environment and meeting environmental protection requirements. Simultaneously, the dust collector / energy saver can recover waste heat from the flue gas and convert it into usable thermal energy. In this application, the dust collector / energy saver uses the recovered waste heat to preheat the water before it enters the steam generator cavity, ensuring that the water in the steam generator has a certain temperature in its initial state. This reduces energy consumption during subsequent heating, further improving the thermal efficiency and energy-saving effect of the equipment, and thus enhancing the energy efficiency and economy of the steam generator.

[0031] Preferably, a drain pipe with a valve is provided at the bottom of the steam generator body 11. By providing a drain pipe with a valve, impurities, sewage, and sediments accumulated in the system can be periodically removed during the operation of the steam generator, thereby effectively preventing the accumulation of impurities from affecting the heat exchange efficiency and maintaining the normal operation of the steam generator.

[0032] Preferably, the outer casing 7 described in this application is provided with a heat insulation layer. The heat insulation layer effectively reduces heat loss to the external environment during steam generator operation, improves thermal energy utilization, and thus enhances the overall working efficiency of the steam generator. Furthermore, the heat insulation layer also reduces the surface temperature of the outer casing 7, reducing the risk of burns to operators and enhancing equipment safety. Simultaneously, this heat insulation layer helps the steam generator maintain stable operation under different environmental conditions, reducing the impact of ambient temperature fluctuations on the heat exchange process and improving the system's thermal efficiency and reliability.

[0033] Preferably, a cyclone device is also provided. This device utilizes the centrifugal force of the airflow to separate particulate matter from the gas, effectively reducing the particulate matter content in the flue gas and ensuring that the emitted flue gas meets environmental standards. Furthermore, the cyclone device reduces the environmental impact of particulate matter and provides a cleaner airflow for subsequent flue gas treatment, further improving the environmental performance and efficiency of the steam generator. Additionally, this steam generator integrates a steam outlet valve, a safety valve, and a pressure gauge. The steam outlet valve controls the steam output flow rate, facilitating the adjustment of steam supply stability; the safety valve automatically releases steam when the system pressure exceeds the set range, preventing equipment damage due to overpressure and ensuring operational safety; the pressure gauge monitors the internal pressure of the steam generator in real time, providing accurate data support for equipment operation and maintenance. Therefore, the integrated design of these components significantly improves the safety, practicality, and ease of operation of the steam generator.

[0034] It should be noted that when using the steam generator for burning biomass pellet fuel in this application,

[0035] (1) Biomass pellet fuel is fully burned in combustion chamber 1, releasing high-temperature flue gas to provide heat energy for steam generator.

[0036] (2) The high-temperature flue gas enters the steam generator body from the combustion chamber 1 and first undergoes radiative heat exchange inside the steam generator body. During this process, the high-temperature flue gas transfers heat to the cavity outside the boiler shell 2 through the wall of the boiler shell 2, causing the water temperature inside the cavity to gradually rise, thus completing the first pass of heat exchange.

[0037] (3) After the first pass of heat exchange, the flue gas enters the interlayer area between the furnace 3 and the water pipe 4 through the flue gas outlet ring 5 between the furnace 3 and the boiler shell 2. At this time, the flue gas comes into contact with the surface of the water pipe 4 and transfers heat to the water in the water pipe 4 through convection heat exchange, further heating the water in the cavity. At this time, the flue gas temperature drops to about 450°C, completing the second pass of heat exchange.

[0038] (4) After the flue gas flows from top to bottom, it will be blocked by the wall of the shell 7 and turn upward to flush the water pipe 4 away from the outside of the steam generator body. At this time, the flue gas will undergo convective heat transfer through the outer wall of the water pipe 4, transferring heat to the water in the water pipe 4, thus completing the third pass of heat exchange. After three passes of heat exchange, the water in the water chamber will continue to absorb heat and continuously vaporize, producing wet steam.

[0039] (4) The generated wet steam enters the steam collector 12 through the connecting pipe 6. The flue gas after the third pass heat exchange continues to rise, scouring the outer wall of the steam collector 12, completing the fourth pass heat exchange. In addition, the wet steam continuously collides with the walls of the outer cylinder 8, the inner cylinder 9, and the spiral flow channel 10. During this process, the moisture in the wet steam is removed through heat exchange and collisions, generating high-quality dry steam that meets the dryness requirements for industrial steam. The dry steam is then discharged from the steam outlet valve through the steam outlet pipe seat and transported to where steam is needed. The flue gas after four passes of heat exchange enters the dust collector. At this stage, the waste heat in the flue gas is recovered and used to preheat the feedwater. Simultaneously, the dust collector filters particulate matter and pollutants from the flue gas, ensuring that the emitted flue gas meets environmental protection requirements. Finally, the treated flue gas is discharged into the atmosphere through the chimney.

[0040] This invention provides a steam generator for burning biomass pellet fuel. By optimizing the heat exchange process between feedwater and heated flue gas, it achieves efficient thermal energy utilization and improved steam quality. Specifically, feedwater enters the steam generator body through radiative heat exchange via the high-temperature heated flue gas in combustion chamber 1, convective heat exchange in the interlayer between the steam generator body and water pipe 4, and convective heat exchange on the side of water pipe 4 away from the steam generator body. During multiple heat exchange cycles, the feedwater in the steam generator body gradually absorbs heat and continuously vaporizes, generating a continuous stream of wet steam. The wet steam then enters the steam collector 12 and completes heat exchange with the rising heated flue gas. Through further heating of the wet steam, the dryness of the steam is significantly improved, meeting industrial requirements and thus ensuring steam quality to meet the high-quality steam demand in different scenarios. This multi-pass heat exchange design fully utilizes the heat from the heated flue gas generated by combustion, effectively reducing heat energy waste and improving fuel utilization while ensuring efficient heat exchange. Meanwhile, the optimized heat exchange path allows the feedwater to gradually heat up and vaporize, avoiding localized overheating or thermal efficiency loss, and ensuring the stability and uniformity of the heat exchange process. Furthermore, by performing a final pass heating on the wet steam in the steam collector 12, not only is the steam dryness improved, but the overall system thermal energy utilization rate is also optimized. Therefore, this biomass pellet fuel-fired steam generator achieves high thermal energy utilization efficiency, meeting the technical goals of energy saving and high efficiency, while also considering environmental protection and practicality.

[0041] Example 2:

[0042] This embodiment 2 is largely the same as embodiment 1, except that steel fins are not provided in this embodiment. Instead, the sides of adjacent water pipes are connected, and a notch is provided on the side of the water pipe near the combustion chamber to allow the heated flue gas generated in the combustion chamber to pass through.

[0043] In this embodiment, the high-temperature flue gas generated in the combustion chamber first undergoes radiative heat exchange inside the steam generator body, transferring heat to the water cavity outside the boiler shell, completing the initial heating. After the first pass of heat exchange, the heated flue gas enters the interlayer between the water pipe and the boiler shell through the flue gas outlet ring. Through the convective heat exchange process in the interlayer, the flue gas comes into direct contact with the surface of the water pipe, transferring heat to the water inside the pipe, further heating the water in the cavity, completing the second pass of heat exchange. Then, the flue gas overflows through the bottom notch, and then moves upward from bottom to top on the side of the water pipe away from the steam generator body. During this process, the flue gas undergoes convective heat exchange with the water inside the pipe, further increasing the water temperature and continuously vaporizing it to produce wet steam. Although the steel fins are eliminated, this structure still ensures the high-efficiency heat exchange capacity and thermal energy utilization efficiency of the steam generator, achieving the goals of energy saving, environmental protection, and high-quality steam output.

[0044] Alternatively, the water pipe may be a single pipe arranged in a ring around the outside of the steam generator body, with an exhaust port on the side near the combustion chamber, for the flue gas after the second pass heat exchange to be discharged from the exhaust port for the third pass heat exchange.

[0045] The above-disclosed embodiments are merely some preferred embodiments of the present utility model, and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent changes made in accordance with the scope of the present utility model patent application shall still fall within the scope of the present utility model.

Claims

1. A steam generator for burning biomass pellet fuel, comprising a combustion chamber, a shell, a steam collector arranged in the shell, and a steam generator body connected with the steam collector, wherein the steam generator body comprises a kettle shell and a furnace, the kettle shell is hollow inside and connected with the combustion chamber at one end, and the furnace is sleeved outside the kettle shell and forms a cavity for storing water between the kettle shell and the furnace, characterized in that: A ring of water pipes is provided on the outside of the furnace shell, and the two ends of the water pipes are respectively connected to the two ends of the furnace shell along its length and communicate with the cavity. A smoke outlet ring is provided on the side wall of the main body of the steam generator, and the opening of the smoke outlet ring faces the water pipes, so that the heated flue gas generated in the combustion chamber forms a multi-pass heating in the shell. ​ 2. The biomass pellet fuel-fired steam generator according to claim 1, wherein The combustion chamber is located at the bottom of the main body of the steam generator, and the steam collection box is located at the top of the main body of the steam generator.

3. The biomass pellet fuel-fired steam generator according to claim 1, wherein A steel fin is installed between each water pipe. The two sides of the steel fin are connected to two adjacent water pipes respectively. The side of the steel fin away from the combustion chamber is connected to the furnace shell.

4. The steam generator for burning biomass pellet fuel as described in claim 1, characterized in that, The water pipes are connected on adjacent sides, and a notch is provided on the side of the water pipes near the combustion chamber to allow the heated flue gas generated in the combustion chamber to pass through.

5. The biomass pellet fuel-fired steam generator according to claim 1, wherein The steam collector includes an outer cylinder and an inner cylinder fitted inside the outer cylinder. A steam chamber is formed between the outer cylinder and the inner cylinder, and the steam chamber is connected to the chamber through a connecting pipe.

6. The biomass pellet fuel-fired steam generator according to claim 5, wherein A spiral flow channel is welded inside the steam chamber.

7. The biomass pellet fuel-fired steam generator according to claim 5, wherein The inner cylinder of the steam collecting box is hollow and is connected to the boiler shell.

8. The biomass pellet fuel-fired steam generator according to claim 1, wherein Multiple soot blowing nozzles are provided on the side of the housing away from the combustion chamber.

9. The biomass pellet fuel-fired steam generator according to claim 1, wherein A smoke exhaust port is provided on the side of the housing away from the combustion chamber, and a dust removal and energy-saving device is connected to the smoke exhaust port.

10. The biomass pellet fuel-fired steam generator according to claim 1, wherein A drain pipe with a valve is installed at the bottom of the main body of the steam generator.

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