Updraft type fixed bed biomass gasifier softened water heating system and heating method

Abstract

The invention relates to an updraft type fixed bed biomass gasifier softened water heating system and a heating method. The softened water heating system specifically comprises a circulating cooling subsystem and a softened water heating subsystem; the circulating cooling subsystem comprises a gasification furnace body, a water jacket annularly arranged on the outer wall of the gasification furnace body, and a water return tank and a water supply tank which are connected with the water jacket; cooling water circulates in the water jacket, and the water jacket, the water return tank and the water supply tank form internal circulation; the softened water heating subsystem comprises a softened water supply tank connected with the water return tank, a coal economizer connected with the water jacket and a deaerator connected with the coal economizer; a metal coil pipe is arranged in the water return tank, softened water in the softened water supply tank flows through the metal coil pipe and then is input into the water jacket for heat exchange, and then the softened water is output from the water jacket and sequentially flows through the economizer and the deaerator. Compared with the prior art, cooling water recycling of the updraft fixed bed biomass gasifier and recycling of waste heat of a heat supply station are both considered.

Description

Technical Field

[0001] The present invention relates to the technical field of gasifiers, and particularly to an upward suction fixed-bed biomass gasifier softened water heating system and a heating method thereof. Background Art

[0002] The upward suction fixed-bed biomass gasifier consists of the following main components: a gasifier feeding device, a gasifier body (including a furnace explosion-proof and pressure-relief device, a water-cooled jacket, a tower-shaped grate, an ash pan, etc.), a circulating water system, a gasifier emergency relief device (including pipeline valves, a sky lantern, and an ignition device), a gasification air supply device, etc.

[0003] Circulating cooling water passes through the water-cooled jacket of the gasifier to cool down the gasifier body for two reasons: one is to prevent the temperature of the gasifier cylinder from being too high, which may cause the material to soften and reduce the strength and hardness of the cylinder, thus protecting the cylinder; the other is to isolate the outer wall of the high-temperature gasifier to prevent accidents where people are scalded when touching the outer wall of the gasifier. When the gasifier load is high and the gasifier temperature exceeds the limit, the consumption of circulating cooling water is large, and it is often necessary to add the amount of cooling circulating water irregularly to ensure that the temperature of the gasifier body remains within a safe range, and the recycling rate is low.

[0004] In addition, generally, the temperature of the circulating cooling water after heat exchange with the gasifier cylinder will generally reach 80 - 90 °C, and then it flows back into the circulating water tank. After the water temperature drops, it is used to cool down the gasifier body again for recycling. In addition, the flue gas discharged from the boiler also takes away most of the heat. If this heat energy can be used for heat exchange and temperature rise of a suitable object, a lot of energy consumption can be saved.

[0005] CN220567908U discloses a waste heat recovery device for the water-cooled structure of a gasifier jacket. Through the mutual cooperation of structures such as a connecting pipe, a shunt plate, a heat conduction pipe, and a confluence plate, the heat carried by the cooling water can be utilized, so as to heat the softened water inside the softening tank. However, in the above-mentioned recovery device, the cooling water in the water jacket is directly input into the heat conduction pipe and then heat-exchanged with the softened water in the softening tank to raise the temperature of the softened water. The temperature-raising effect is limited, and the recycling rates of the cooling water and the softened water still need to be improved.

[0006] Therefore, in order to ensure the recycling of the cooling water of the upward suction fixed-bed biomass gasifier and the recovery and utilization of the waste heat of the heat supply station to maximize the energy-saving purpose, it is still necessary to develop a new softened water heating system for the upward suction fixed-bed biomass gasifier. Summary of the Invention

[0007] The purpose of the present invention is to provide an upward suction fixed-bed biomass gasifier softened water heating system and a heating method thereof in order to further improve the recycling effect of the gasifier cooling water and the temperature-raising effect of the softened water.

[0008] The object of the present invention can be achieved by the following technical solutions:

[0009] The present invention first provides an up-draft fixed-bed biomass gasifier soft water heating system, which includes a circulating cooling subsystem and a soft water heating subsystem;

[0010] The circulating cooling subsystem includes a gasifier body, a water jacket arranged around the outer wall of the gasifier body, a return water tank connected to the water jacket, and a feed water tank connected to the outlet of the return water tank; cooling water circulates in the water jacket, and the outlet of the feed water tank is connected to the water jacket, so that the water jacket, the return water tank and the feed water tank form an internal circulation of the cooling water;

[0011] The soft water heating subsystem includes a soft water supply tank connected to the return water tank, an economizer connected to the water jacket, and a deaerator connected to the economizer; a metal coil is arranged in the return water tank, and the soft water in the soft water supply tank flows through the metal coil and then is input into the water jacket for heat exchange, and then is output from the water jacket and flows through the economizer and the deaerator in sequence.

[0012] Further, the central reaction temperature in the gasifier body is 700 - 800 °C, and the cooling water in the water jacket is heated to 80 - 90 °C after heat exchange with the gasifier body.

[0013] Further, a feed water pump is arranged in the pipeline between the feed water tank and the water jacket.

[0014] Further, the outlet of the feed water pump is connected to the water jacket through at least two feed water branches.

[0015] Further, the soft water is heated from room temperature to 40 - 50 °C after flowing through the metal coil and exchanging heat with the circulating water in the return water tank.

[0016] Furthermore, the soft water input into the water jacket after flowing through the metal coil exchanges heat with the cooling water in the water jacket, and the temperature of the soft water rises to 75 - 85 °C.

[0017] Further, a soft water circulation pipe is connected between the metal coil and the economizer, and the soft water circulation pipe is communicated with the water jacket and passes through the bottom of the water jacket.

[0018] Further, the soft water is heated to not less than 100 °C by the boiler flue gas at 80 - 140 °C after being input into the economizer from the water jacket.

[0019] Further, a spiral film tube, a water spraying grid and a packing layer are sequentially arranged from top to bottom in the deaerator, and a steam inlet and a soft water inlet are provided.

[0020] Furthermore, the softened water enters from the softened water inlet and is input into the spiral film tube. The formed water film skirt falls and exchanges heat with the steam entering from the steam inlet. The water in the water film skirt continues to flow through the randomly stacked packing layer after heat exchange through the water spraying grate and is further heated and deaerated under the steam.

[0021] The present invention also provides a heating method for a softened water heating system of an updraft fixed-bed biomass gasifier, including the following steps:

[0022] S1: The softened water flows through the metal coil pipe for primary heating after being output from the softened water supply tank;

[0023] S2: The softened water after primary heating is input into the water jacket and exchanges heat with the cooling water in the water jacket for secondary heating;

[0024] S3: The softened water after secondary heating is input into the economizer for tertiary heating and then input into the deaerator for deaeration.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The circulating cooling subsystem of the present invention can ensure the stability of the temperature field of the gasifier and realize the efficient recycling of cooling water; the softened water heating subsystem utilizes the metal coil pipe in the return water tank to recover waste heat and forms a multi-level heat energy utilization system through the water jacket, economizer, and deaerator. By combining the circulating cooling subsystem and the softened water heating subsystem, the present invention realizes the efficient energy cascade utilization based on the updraft fixed-bed biomass gasifier, taking into account the recycling of the cooling water of the updraft fixed-bed biomass gasifier and the recovery of waste heat from the heat supply station, and can significantly improve the recycling effect of the cooling water of the gasifier and the temperature rise effect of the softened water.

[0027] (2) The softened water of the present invention can make full use of the residual heat energy in the factory area (circulating cooling water of the gasifier, boiler flue gas). After multi-stage gradient heating by the metal coil pipe, water jacket, and economizer, it can be heated from room temperature to about 100°C, which can maximize the utilization of the heat energy in the factory area, make full use of the waste heat inside the heat supply station, minimize the use of energy, promote the energy-saving work in the factory area, and promote the green transformation of the heat supply station.

[0028] (3) The softened water input into the deaerator of the present invention undergoes three-stage gradient heating processes through the metal coil pipe, water jacket, and economizer in sequence, making full use of the heat energy of the gasifier body and circulating cooling water, greatly reducing the usage amount of deaeration steam, and further achieving the purpose of energy conservation. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the overall structure of the gasifier softened water heating system of the present invention.

[0030] Figure 2 Schematic diagram of the gradient temperature rise of softened water in Embodiment 3 of the present invention.

[0031] Figure 3 Schematic diagram of the overall structure of the deaerator in Embodiment 4 of the present invention.

[0032] Figure 4 Schematic diagram of the internal structure of the deaerator in Embodiment 4 of the present invention.

[0033] Description of the marks in the figure:

[0034] 1 - Gasifier body, 2 - Water jacket, 3 - Return water tank, 4 - Feed water tank, 5 - Softened water supply tank, 6 - Economizer, 7 - Deaerator, 71 - Spiral film tube, 72 - Water spraying grid, 73 - Packing layer, 74 - Steam inlet, 75 - Softened water inlet, 8 - Metal coil tube, 9 - Feed water pump, 10 - Softened water flow pipe. Detailed implementation manners

[0035] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0036] In the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention; the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0038] Embodiment 1:

[0039] This embodiment provides a softened water heating system for an updraft fixed-bed biomass gasifier, which specifically includes a circulating cooling subsystem and a softened water heating subsystem.

[0040] like Figure 1 As shown, the circulating cooling subsystem of this embodiment includes a gasifier body 1, a water jacket 2 arranged around the outer wall of the gasifier body 1, a return water tank 3 connected to the water jacket 2, and a feed water tank 4 connected to the outlet of the return water tank 3. Cooling water flows through the water jacket 2, and the outlet of the feed water tank 4 is connected to the water jacket 2, so that the water jacket 2, the return water tank 3, and the feed water tank 4 form an internal circulation of cooling water.

[0041] The softened water heating subsystem of this embodiment includes a softened water supply tank 5 connected to the return water tank 3, an economizer 6 connected to the water jacket 2, and a deaerator 7 connected to the economizer 6. A metal coil 8 is installed within the return water tank 3. Softened water from the softened water supply tank 5 flows through the metal coil 8 and then enters the water jacket 2 for heat exchange. It is then discharged from the water jacket 2 and flows sequentially through the economizer 6 and deaerator 7.

[0042] The method for heating softened water using the softened water heating system of the updraft fixed-bed biomass gasifier in this embodiment specifically includes the following steps:

[0043] S1: Softened water is output from the softened water supply tank 5 and flows through the metal coil 8 for primary heating;

[0044] S2: The softened water after the primary heating is input into the water jacket 2 and then exchanges heat with the cooling water in the water jacket for secondary heating;

[0045] S3: The softened water after secondary heating is input into the economizer 6 for tertiary heating and then input into the deaerator 7 for deoxygenation.

[0046] This embodiment achieves efficient cascaded energy utilization based on an updraft fixed-bed biomass gasifier through the combined use of a circulating cooling subsystem and a softened water heating subsystem. The circulating cooling subsystem of this embodiment includes a water jacket 2, a return water tank 3, and a feed water tank 4 that form an internal circulation, to ensure a stable temperature field in the gasifier body 1 and achieve efficient recycling of cooling water. The softened water heating subsystem of this embodiment utilizes the metal coil 8 built into the return water tank 3 to recover waste heat. The softened water is preheated before entering the water jacket 2 for heat exchange. The economizer 6 further recovers the waste heat of the flue gas. Through three heating steps, a multi-stage thermal energy utilization system is formed, fully utilizing the waste heat of the entire system to achieve energy conservation.

[0047] Example 2:

[0048] This embodiment provides a softened water heating system for an updraft fixed-bed biomass gasifier, which specifically includes a circulating cooling subsystem and a softened water heating subsystem.

[0049] The difference from Example 1 is that the circulating cooling subsystem of this embodiment includes a gasifier body 1, a water jacket 2 arranged around the outer wall of the gasifier body 1, a return water tank 3 connected to the water jacket 2, and a water supply tank 4 connected to the outlet of the return water tank 3. Cooling water flows through the water jacket 2, and the outlet of the water supply tank 4 is connected to the water jacket 2, so that the water jacket 2, the return water tank 3, and the water supply tank 4 form an internal circulation of cooling water. In this embodiment, a water supply pump 9 is provided in the pipeline between the water supply tank 4 and the water jacket 2, and the outlet of the water supply pump 9 is connected to the water jacket 2 by at least two water supply branches. The upward-draft fixed-bed biomass gasifier of this embodiment is provided with a circulating cooling subsystem, which serves to cool the gasifier body 1 and prevent damage to the gasifier drum due to excessive temperatures. At the same time, the structure of the water jacket 2 insulates the high-temperature outer wall of the gasifier drum to prevent accidents such as burns caused by contact with the outer wall of the gasifier.

[0050] The central reaction temperature within the gasifier body 1 of this embodiment is 700-800°C, and the cooling water within the water jacket 2 can be heated to 80-90°C after heat exchange with the gasifier body 1. Since biomass raw materials have a high volatile content and are easily gasified, but their ash melting point is relatively low (900°C), during the biomass gasification process, volatiles begin to precipitate when the raw material is heated to 250°C. By 350°C, more than 80% of the volatiles have precipitated, forming coke. Therefore, the central reaction temperature of the gasification within the gasifier body 1 must be as high as 700-800°C; otherwise, a large amount of coke will precipitate, seriously reducing the gasification efficiency.

[0051] Example 3:

[0052] This embodiment provides a softened water heating system for an updraft fixed-bed biomass gasifier, which specifically includes a circulating cooling subsystem and a softened water heating subsystem.

[0053] The difference from Example 1 is that the softened water heating subsystem of this embodiment includes a softened water supply tank 5 connected to the return water tank 3, an economizer 6 connected to the water jacket 2, and a deaerator 7 connected to the economizer 6. A metal coil 8 is provided within the return water tank 3. Softened water from the softened water supply tank 5 flows through the metal coil 8 and is then fed into the water jacket 2 for heat exchange. It is then discharged from the water jacket 2 and flows sequentially through the economizer 6 and deaerator 7.

[0054] Specifically, if Figure 2As shown in the figure, the softened water in this embodiment flows through the metal coil 8 and exchanges heat with the circulating water in the return water tank 3, and is heated from room temperature to 40 - 50°C. The softened water flowing through the metal coil 8 enters the water jacket 2 and exchanges heat with the cooling water in the water jacket 2, and the temperature of the softened water rises to about 80°C. The metal coil 8 in this embodiment is a copper coil with a pipe diameter of DN80. The softened water enters the economizer 6 from the water jacket 2 and is heated by the boiler flue gas at 80 - 140°C to not less than 100°C. A softened water circulation pipe 10 is connected between the metal coil 8 and the economizer 6 of this embodiment. The softened water circulation pipe 10 communicates with the water jacket 2 and passes through the bottom of the water jacket 2.

[0055] In this embodiment, a gradient heating of the softened water is achieved through a three - stage heat exchange system. The heating method specifically includes the following steps:

[0056] S1: After the softened water is output from the softened water supply tank 5, it flows through the metal coil 8 for primary heating;

[0057] S2: The softened water after primary heating enters the water jacket 2 and exchanges heat with the cooling water in the water jacket for secondary heating;

[0058] S3: The softened water after secondary heating enters the economizer 6 for tertiary heating, and then enters the deaerator 7.

[0059] Specifically, the softened water in the metal coil 8 of the return water tank 3 is heated from room temperature to 40 - 50°C by using the waste heat of the circulating cooling water, recovering the low - temperature waste heat; after the softened water enters the water jacket 2, it directly contacts and exchanges heat with the high - temperature cooling water, and the temperature rises to about 80°C, realizing the efficient transfer of heat energy in the medium - temperature section; the economizer 6 uses the boiler flue gas (80 - 140°C) to heat the softened water to ≥100°C, completing the deep utilization of heat energy.

[0060] Example 4:

[0061] This embodiment provides a softened water heating system for an up - draft fixed - bed biomass gasifier, which specifically includes a circulating cooling subsystem and a softened water heating subsystem.

[0062] The difference from Example 1 is that, as Figures 3 - 4As shown in the figure, in this embodiment, the heated softened water is fed into the deaerator 7, where it is heated to the saturation temperature at the corresponding pressure together with steam for deaeration treatment. Since whether it can be heated to the saturation temperature at the corresponding pressure is related to the contact surface area between water and steam, the deaerator 7 in this embodiment adopts the method of spiral film tubes 71, water shower grids 72 and an irregular packing layer 73 to increase the water-steam contact surface. Specifically, in the deaerator 7 of this embodiment, a spiral film tube 71, a water shower grid 72 and a packing layer 73 are successively arranged from top to bottom, and a steam inlet 74 and a softened water inlet 75 are provided. After the softened water is introduced from the softened water inlet 75, it is input into the spiral film tube 71, and the formed water film skirt falls and exchanges heat with the steam introduced from the steam inlet 74. The water in the water film skirt exchanges heat through the water shower grid 72 and then continues to flow through the irregularly stacked packing layer 73 and is further heated under the steam. At this time, the gas dissolved in the water is precipitated to achieve the purpose of deaeration. The packing layer 73 can be made of materials such as quartz sand and stainless steel packing.

[0063] Since the softened water introduced from the softened water inlet 75 has gone through three heating processes in the metal coil 8, the water jacket 2 and the economizer 6 in sequence, and has fully utilized the heat energy of the gasifier body 1 and the circulating cooling water, the consumption of deaeration steam will also be greatly reduced, and the purpose of energy conservation can be further achieved.

[0064] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those who are familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. An up-draft fixed-bed biomass gasifier softened water heating system, characterized in that, It includes a circulating cooling subsystem and a softened water heating subsystem; The circulating cooling subsystem includes a gasifier body (1), a water jacket (2) arranged around the outer wall of the gasifier body (1), a return water tank (3) connected to the water jacket (2), and a feed water tank (4) connected to the outlet of the return water tank (3); cooling water circulates in the water jacket (2), and the outlet of the feed water tank (4) is connected to the water jacket (2) so that the water jacket (2), the return water tank (3), and the feed water tank (4) form an internal circulation of the cooling water; The softened water heating subsystem includes a softened water supply tank (5) connected to the return water tank (3), a economizer (6) connected to the water jacket (2), and a deaerator (7) connected to the economizer (6); a metal coil pipe (8) is arranged in the return water tank (3), and the softened water in the softened water supply tank (5) flows through the metal coil pipe (8) and then is input into the water jacket (2) for heat exchange, and then is output from the water jacket (2) and flows through the economizer (6) and the deaerator (7) in sequence.

2. The softened water heating system of an up-draft fixed-bed biomass gasifier according to claim 1, wherein The central reaction temperature in the gasifier body (1) is 700 - 800 °C, and the cooling water in the water jacket (2) is heated to 80 - 90 °C after heat exchange with the gasifier body (1).

3. The soft water heating system of an up-draft fixed bed biomass gasifier according to claim 1, wherein, A feed water pump (9) is arranged in the pipeline between the feed water tank (4) and the water jacket (2).

4. The softened water heating system of an up-draft fixed-bed biomass gasifier according to claim 3, wherein The outlet of the feed water pump (9) is connected to the water jacket (2) through at least two feed water branches.

5. The soft water heating system of an up-draft fixed-bed biomass gasifier according to claim 1, characterized in that, The softened water is heated from room temperature to 40 - 50 °C after flowing through the metal coil pipe (8) and exchanging heat with the circulating water in the return water tank (3); The softened water flowing through the metal coil pipe (8) exchanges heat with the cooling water in the water jacket (2) after being input into the water jacket (2), and the temperature of the softened water rises to 75 - 85 °C.

6. The soft water heating system of an up-draft fixed bed biomass gasifier according to claim 1, wherein, A softened water circulation pipe (10) is connected between the metal coil pipe (8) and the economizer (6), and the softened water circulation pipe (10) is communicated with the water jacket (2) and penetrates out from the bottom of the water jacket (2).

7. The soft water heating system of an up-draft fixed-bed biomass gasifier according to claim 1, wherein, The softened water is heated to not less than 100 °C by the boiler flue gas at 80 - 140 °C after being input into the economizer (6) from the water jacket (2).

8. The soft water heating system of an up-draft fixed bed biomass gasifier according to claim 1, characterized in that, In the deaerator (7), a spiral film tube (71), a water shower grid (72), and a packing layer (73) are arranged from top to bottom in sequence, and a steam inlet (74) and a softened water inlet (75) are provided.

9. The soft water heating system of an up-draft fixed-bed biomass gasifier according to claim 8, wherein, The softened water is input into the spiral film tube (71) after being introduced from the softened water inlet (75), and the formed water film skirt falls and exchanges heat with the steam introduced from the steam inlet (74). The water of the water film skirt exchanges heat through the water shower grid (72) and then continues to flow through the randomly stacked packing layer (73) and is further heated and deaerated under the steam.

10. A heating method for the softened water heating system of the up-draft fixed-bed biomass gasifier according to any one of claims 1-9 of the utility model, characterized in that, It includes the following steps: S1: The softened water flows through the metal coil pipe (8) for primary heating after being output from the softened water supply tank (5); S2: The softened water after primary heating is input into the water jacket (2) and exchanges heat with the cooling water in the water jacket (2) for secondary heating; S3: The softened water after secondary heating is input into the economizer (6) for tertiary heating, and then is input into the deaerator (7) for deaeration.

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