Anti-dew-point intelligent glass tube air preheater

Abstract

A dew-point-preventing intelligent glass tube air preheater comprises an air preheater body, a hot smoke inlet, a hot air outlet, a cold air inlet, a cold smoke outlet, a plurality of heat exchange modules, a bridging air duct, a cold smoke outlet header, a built-in spoiler glass tube, a hot smoke bypass and a flue bypass, wherein the hot smoke inlet, the hot air outlet, the cold air inlet, the cold smoke outlet, the heat exchange modules, the bridging air duct, the cold smoke outlet header, the built-in spoiler glass tube, the hot smoke bypass and the flue bypass are arranged on the air preheater body. The low-temperature section heat exchange module adopts glass tubes as heat exchange elements, spoilers are arranged in the glass tubes, and the heat transfer coefficient of an inner film is increased; and a flue gas heat bypass is arranged, so that part of hot flue gas is mixed with cold flue gas at an outlet of the air preheater. The device solves the problems of sulfuric acid dew point corrosion and carbonic acid dew point corrosion generated by an air preheater, flue gas downstream equipment, a flue and a chimney due to the fact that the exhaust gas temperature is too low, and the direction of the rotating guide plate can be adjusted by rotating the handle according to the load of a heating furnace and the pressure and flow of fluid. And fluid in the whole air preheater is distributed more uniformly, the heat exchange efficiency of the whole air preheater is improved, the dew point corrosion risk is reduced, and the service life of equipment is prolonged.

Description

Technical Field

[0001] This utility model belongs to the field of heating furnace technology and relates to an anti-dew point intelligent glass tube air preheater. Background Technology

[0002] In recent years, the flue gas temperature of heating furnaces has continued to decrease, and the cold flue gas outlet temperature of air preheaters has fallen below 80℃. Under these circumstances, the flue gas ducts and fan equipment downstream of the air preheater are threatened by sulfuric acid dew point corrosion and carbonic acid dew point corrosion, seriously affecting equipment safety. Although fuel gas desulfurization measures can alleviate the sulfuric acid dew point corrosion problem to some extent, the carbonic acid corrosion problem remains difficult to overcome.

[0003] Meanwhile, as heating furnaces become larger, the size of air preheaters is also increasing. In existing large air preheaters, airflow deviation is prone to occur within the internal heat exchange modules. Specifically, the airflow velocity is high in the central area and slow at the periphery, creating an airflow "dead zone." Within this dead zone, the heat exchange surface cannot perform its function, resulting in low utilization of the air preheater's heat exchange surface and wasted resources. Furthermore, uneven heat exchange prevents sufficient heat exchange between flue gas and air, leading to increased exhaust gas temperature and further energy waste. Utility Model Content

[0004] The purpose of this invention is to provide an anti-dew-point intelligent glass tube air preheater. This device not only prevents itself from suffering acid dew-point corrosion, but also protects downstream equipment such as flues, fans, and chimneys from acid corrosion. Simultaneously, it effectively avoids airflow deviation within the internal heat exchange module, reduces the generation of airflow "dead zones," and maximizes the heat exchange capacity of the heat exchange surface, achieving high-efficiency heat exchange with relatively low investment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A dew-proof intelligent glass tube air preheater includes an air preheater body and a hot flue gas inlet, a hot air outlet, a cold air inlet, a cold flue gas outlet, multiple heat exchange modules, a bridging air duct, a cold flue gas outlet header, a glass tube with built-in baffles, a hot flue gas bypass, and a flue bypass.

[0007] The low-temperature heat exchange module uses glass tubes as heat exchange elements, and the glass tubes have built-in baffles to increase the heat transfer coefficient of the inner membrane.

[0008] The baffle is made of thin steel plate wound and welded onto a round steel bar, with threads machined at both ends of the round steel bar. The stainless steel cap consists of two stainless steel rings connected by three connecting plates. The inner diameter of the outer ring is larger than that of the glass tube, and the inner diameter of the inner ring is larger than that of the wound round steel bar. The glass tube, baffle, and stainless steel cap are connected together by nuts. After tightening the nuts, the baffle is located in the center of the glass tube and does not contact the glass tube.

[0009] Hot flue gas bypass design: A hot flue gas bypass is installed to mix a portion of the hot flue gas with the cold flue gas at the air preheater outlet, and a regulating valve is installed on the bypass. A portion of the high-temperature flue gas is drawn out through this bypass and mixed with the cold flue gas at the air preheater outlet. When the flue gas cools down in the air preheater due to heat exchange, and the temperature is below the sulfuric acid dew point temperature, sulfuric acid dew will condense on the heat exchange surface of the glass tubes. At this time, the flue gas temperature will drop to A degrees. At A degrees, the acid is saturated, and the flue gas outlet temperature A of the air preheater is lower than the design exhaust temperature B. The hot flue gas bypass allows the high-temperature flue gas to mix with the flue gas at temperature A, raising the temperature to B degrees. At B degrees, both the acid and water in the flue gas are undersaturated. As long as the flue gas temperature in downstream flue ducts and equipment such as chimney fans is greater than A, acid dew point corrosion and condensation will not occur. During the design phase, the specific value of temperature B can be determined by calculating the heat dissipation downstream of the air preheater flue gas.

[0010] Baffle plate configuration: Baffle plates are installed in the internal cavities between heat exchange modules and in the internal cavity below the hot flue gas inlet. Each baffle plate consists of a fixed baffle plate, a rotating baffle plate, a sealed bearing, and a handle. The fixed baffle plate is fixed within its designated internal cavity; the rotating baffle plate is connected to a shaft within the cavity, with both ends of the shaft connected to the outer wall of the equipment via sealed bearings. One end of the shaft extends beyond the outer wall and is fitted with a handle, which rotates the rotating baffle plate. Furthermore, multiple baffle plates are arranged in parallel and spaced intervals below the hot flue gas inlet and between multiple heat exchange modules. Both the fixed and rotating baffle plates are serrated and have ventilation holes to enhance airflow mixing. The handle is equipped with a locking device to secure the rotating baffle plate in its rotated position. The baffle plate can adjust the uniformity of gas flow on the flue gas side plane of the air preheater body. Combined with the adjustment function of the bridging duct, it can intelligently adjust the air preheater's exhaust gas temperature according to the temperature feedback signal from the thermometer, so as to reduce the airflow to the minimum, make the airflow most uniform, and place the baffle plate in the optimal position.

[0011] Cross-connection duct design: The inner cavity of the cross-connection duct is equipped with a cross-connection duct guide plate, whose function is to regulate the uniformity of airflow within the cross-connection duct. Based on feedback signals from multiple field thermometers longitudinally positioned outside the hot air outlet, the guide plate on the cross-connection duct is intelligently adjusted to ensure that the hot air outlet temperature of the air preheater reaches its maximum value, at which point the airflow is most uniform and the guide plate is in the optimal position.

[0012] Other configurations: The cold flue gas outlet header is equipped with alkaline beads to neutralize the acidic water produced by the flue gas, ensuring that the flue gas condensate meets emission standards. A wire mesh demister is installed at the cold flue gas outlet, which not only removes water droplets from the flue gas, preventing water droplets from impacting the induced draft fan blades and causing vibration damage to the induced draft fan, thus protecting the induced draft fan, but also ensures uniform mixing of hot and cold flue gas.

[0013] Staff can observe the adjustment effect of the baffle plate based on the on-site thermometers and the gas outlet temperature. Since each heat exchange module has multiple on-site thermometers, the angle of the baffle plate can be adjusted according to the thermometer readings. When the exhaust gas temperature reaches its lowest value, the baffle plate is at its optimal angle.

[0014] This invention effectively solves the problems of sulfuric acid dew point corrosion and carbonic acid dew point corrosion in air preheaters, downstream equipment, flues, and chimneys caused by excessively low flue gas temperatures. Furthermore, the direction of the rotating guide plate can be adjusted by turning the handle according to the furnace load and the pressure and flow rate of the fluid, optimizing the flow guidance effect and making the fluid distribution inside the entire air preheater more uniform and heat exchange more complete. This improves the overall heat exchange efficiency of the air preheater, reduces the risk of dew point corrosion, and extends the service life of the equipment. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This is a perspective view of the present utility model;

[0017] Figure 3 Schematic diagram of a baffle plate built into a glass tube

[0018] Figure 4 This is a schematic diagram of the structure of the guide plate of this utility model;

[0019] Figure 5 This is a schematic diagram of the handle of this utility model;

[0020] Figure 6 This is a schematic diagram of the vent hole of this utility model.

[0021] In the diagram: 1 Fixed guide plate; 2 Rotating guide plate; 3 Shaft; 4 Sealed bearing; 5 Handle; 6 Air preheater body; 7 Alkaline balls; 8 Wire mesh demister; 9 Hot flue gas bypass; 10 Hot flue gas bypass valve; 11 On-site thermometer; 12 Vent; 13 Glass tube; 14 Baffle plate; 15 Stainless steel pipe cap; 16 Nut. Detailed Implementation

[0022] Equipment Composition and Layout: Referring to Figures 1 and 2, the dew-proof intelligent glass tube air preheater of this utility model consists of an air preheater body and, on the body, a hot flue gas inlet, a hot air outlet, a cold air inlet, a cold flue gas outlet, multiple heat exchange modules, a bridging duct, a cold flue gas outlet header, a hot flue gas bypass, a hot flue gas bypass valve, local thermometers, a glass tube, baffles, stainless steel pipe caps, and nuts. Multiple baffles are arranged in the inner cavity of the air preheater body 6 below the hot flue gas inlet, in the inner cavity of the air preheater body 6 between the multiple heat exchange modules, and in the inner cavity of the bridging duct. Multiple local thermometers 11 are installed longitudinally on the outer side of each heat exchange module and the hot air outlet.

[0023] Deflector installation and adjustment: Refer to Figure 4. Figure 5 The guide vane consists of a fixed guide vane 1, a rotating guide vane 2, a sealed bearing 4, and a handle 5. The fixed guide vane 1 is fixed at both ends to the corresponding positions within the equipment cavity. The rotating guide vane 2 is connected to a rotating shaft 3 within the corresponding cavity. Both ends of the rotating shaft 3 are connected to the outer wall of the equipment via sealed bearings 4, with one end extending out of the outer wall and fitted with a handle 5. Rotating the handle 5 rotates the rotating guide vane 2. Multiple guide vanes are arranged in parallel and spaced intervals within the air preheater body 6 below the hot flue gas inlet and within the preheater body 6 between multiple heat exchange modules.

[0024] Flue gas conditioning and demisting: A flue gas bypass 9 is installed between the flue gas inlet and outlet of the air preheater. A hot flue gas bypass valve 10 is installed on the flue gas bypass 9 to regulate the flue gas temperature. After mixing, the flue gas passes through a wire mesh demister 8 to remove water droplets, ensuring that the hot and cold flue gas are evenly mixed before entering the downstream flue. The heat extraction point for the flue gas bypass 9 can be either the flue gas inlet or the flue gas between the heat exchange modules.

[0025] Low-temperature heat exchange module assembly: Combination Figure 3 The low-temperature heat exchange module uses a glass tube 13 as the heat exchange element, with baffles 14 installed inside to improve the inner membrane heat transfer coefficient. The baffles are made of thin steel plates wound and welded onto round steel, with threads machined at both ends of the round steel. The stainless steel cap 15 consists of two stainless steel rings connected by three connecting plates; the outer ring's inner diameter is slightly larger than the glass tube, and the inner ring's inner diameter is slightly larger than the wound round steel. The glass tube 13, baffles 14, and stainless steel cap 15 are connected together by nuts. After tightening the nuts 16, the baffles are positioned at the center of the glass tube and do not contact the glass tube.

[0026] The guide vanes are configured with other components as follows: the fixed guide vane 1 and the rotating guide vane 2 are serrated and have ventilation holes 12 (see Figure 6) to enhance airflow mixing. The handle 5 has a locking device to fix the rotating guide vane 2 in its rotated position. The cold flue gas outlet header contains alkaline beads 7 to neutralize the acidic water produced by the flue gas, ensuring that the flue gas condensate meets emission standards. A wire mesh demister 8 is installed at the cold flue gas outlet to remove water droplets from the flue gas, protecting the induced draft fan, and to ensure uniform mixing of hot and cold flue gas.

Claims

1. A dew-proof intelligent glass tube air preheater, characterized in that, The air preheater includes an air preheater body and its hot flue gas inlet, hot air outlet, cold air inlet, cold flue gas outlet, multiple heat exchange modules, crossover duct, cold flue gas outlet header, built-in baffle glass tube, hot flue gas bypass, and flue bypass. The low-temperature heat exchange module uses glass tubes as heat exchange elements, and the glass tubes have built-in baffles to increase the heat transfer coefficient of the inner membrane. A flue gas hot bypass is set up so that a portion of the hot flue gas mixes with the cold flue gas at the air preheater outlet; A guide vane is provided inside the air preheater body at the lower part of the hot flue gas inlet; a guide vane is provided inside the air preheater body between multiple heat exchange modules; a guide vane is provided inside the bridging air duct. Each heat exchange module has multiple field thermometers inside its cavity; multiple field thermometers are also installed longitudinally on the outside of the hot air outlet. The guide plate includes a fixed guide plate, a rotating guide plate, a sealed bearing, and a handle; the fixed guide plate is fixed in the inner cavity of the location; the rotating guide plate is connected to a rotating shaft in the inner cavity of the location; the two ends of the rotating shaft are connected to the outer wall of the equipment through sealed bearings, and one end of the shaft extends out from the outer wall of the equipment at the location and is provided with a handle, which can drive the rotating guide plate to rotate by rotating the handle.

2. The anti-dew-point intelligent glass tube air preheater according to claim 1, characterized in that, The guide vanes inside the air preheater body at the lower part of the hot flue gas inlet and the guide vanes inside the preheater body between multiple heat exchange modules are arranged in parallel and at intervals.

3. The anti-dew-point intelligent glass tube air preheater according to claim 1, characterized in that, Both the fixed and rotating guide vanes are serrated.

4. The anti-dew-point intelligent glass tube air preheater according to claim 1, characterized in that, Ventilation holes are provided on both the fixed and rotating guide plates to enhance airflow mixing.

5. The anti-dew-point intelligent glass tube air preheater according to claim 1, characterized in that, The handle is equipped with a locking device to fix the position of the rotating guide plate after it has rotated.

6. The anti-dew-point intelligent glass tube air preheater according to claim 1, characterized in that, A wire mesh demister is installed at the cold flue gas outlet.

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