Counter-flow and counter-flow non-metal pipe air preheater

Abstract

The utility model relates to a concurrent and countercurrent non-metal tube air preheater, which is provided with a condensate separation tube box and a flue gas outlet, a flue gas inlet is arranged at the top, an air inlet and an air outlet are arranged on the side surface, the same condensate separation tube box is arranged below a concurrent tube bundle and a countercurrent tube bundle, and an air circulation box is arranged between the air inlet tube box and the air outlet tube box. The air circulation box is separated from the flue gas outlet pipe box, the flue gas inlet pipe box and the condensate separation pipe box through the upper pipe plate and the lower pipe plate, the downstream pipe bundle and the countercurrent pipe bundle penetrate through the upper pipe plate and the lower pipe plate to communicate the flue gas inlet pipe box, the flue gas outlet pipe box and the condensate separation pipe box, the heat transfer pipe is a non-metal pipe and is a non-equal-diameter pipe, one end of the heat transfer pipe is provided with a turnup outer edge, and the other end of the heat transfer pipe is provided with a flange. The outer edge of the flange is in contact with the outer surface of the upper tube plate, and the heat transfer tube is sealed with the upper tube plate and the lower tube plate through O-shaped rings. The utility model has the beneficial effects that the O-shaped ring buffers vibration and can adapt to the deformation of the heat exchange tube due to expansion caused by heat and contraction caused by cold due to the sealing of the heat exchange tube at the outer edge of the flange and the O-shaped ring.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of waste heat recycling, and relates to an air preheater of nonmetallic tube bundle. BACKGROUND

[0002] The air preheater for heat exchange between low-temperature end flue gas and air, due to the water and sulfur, carbon and oxygen elements contained in the flue gas, when the flue gas is cooled, the flue gas temperature below the dew point will dew and form acid dew point corrosion.

[0003] Due to the influence of dew, the low-temperature end air preheater flue gas and air side both adopt a once-through structure. This structure has the discharge of condensate on the flue gas side, but due to the low heat transfer efficiency of the equipment and the large equipment footprint.

[0004] The air preheater for heat exchange between low-temperature end flue gas and air solves the dew point corrosion by using anti-dew point corrosion materials, and cast iron air preheaters and non-metallic air preheaters are commonly used. Although the cast iron air preheater has good corrosion resistance and high heat transfer efficiency, it can also cause low-temperature acid dew point corrosion under low-temperature conditions. The non-metallic air preheater material can be divided into graphite, glass, ceramic and PP materials. The toughness of graphite, glass and ceramic materials is poor, and they are prone to breakage during transportation, installation and operation. Although the toughness of PP material is good, its thermal conductivity is poor and the heat transfer efficiency is low. Non-metallic heat transfer pipes are resistant to corrosion and need to be sealed with the preheater tube plate. In order to meet the pressure requirement of the preheater tube plate, the metal composite plate is used for sealing, and the expansion joint method is used for sealing. However, the expansion joint method will loosen over time due to vibration, pressure and deformation of the pipe caused by fluid flow, resulting in leakage of the flowing medium. Therefore, it is a problem in the field to solve the low service life of the expansion joint connection. CONTENT OF THE UTILITY MODEL

[0005] The utility model aims to provide an air preheater which is efficient and corrosion-resistant, reduces the flue gas outlet temperature, and improves the flue gas waste heat recovery efficiency.

[0006] The utility model discloses a technical scheme: a kind of non-metal tube air preheater of forward and reverse flow, it is equipped with flue gas inlet pipe box, condensate separation pipe box, flue gas outlet pipe box, air inlet pipe box, air outlet pipe box, flue gas outlet, flue gas inlet is equipped in top, air inlet, air outlet is in side, forward flow tube bundle and reverse flow tube bundle below are same condensate separation pipe box, air inlet pipe box and air outlet pipe box between are air flow box, air flow box is separated by upper tube plate, lower tube plate and flue gas outlet pipe box, flue gas inlet pipe box, condensate separation pipe box, forward flow tube bundle and reverse flow tube bundle pass through upper tube plate, lower tube plate and make flue gas inlet pipe box, flue gas outlet pipe box and condensate separation pipe box communicate, forward flow tube bundle and reverse flow tube bundle are by multiple heat transfer pipes vertical arrangement, heat transfer pipe is non-metal tube, and for non-equal-diameter pipe, one end has flanging outer edge, flanging outer edge is in contact with the outer surface of upper tube plate, heat transfer pipe and upper tube plate, lower tube plate are sealed by O-ring, and the sidewall of pipeline perforation of upper tube plate, lower tube plate is equipped with annular groove containing O-ring.

[0007] Preferably, the O-ring arranged on the heat transfer pipe is arranged with two on the upper tube plate and the lower tube plate.

[0008] The condensate separation pipe box is provided with a first condensate outlet and a second condensate outlet at the bottom, and the air preheater is supported by a support at the bottom.

[0009] Preferably, the heat transfer pipe is made of PP-GR or PPS-GR material.

[0010] The condensate separation pipe box is provided with a drain plate at the bottom surface, and the drain plate is inclined and arranged towards the middle condensate outlet.

[0011] A vortex breaker is fixed at a position close to the first condensate outlet and the second condensate outlet of the drain plate.

[0012] Further, an air distribution plate is fixed in the air inlet pipe box, and a flue gas distribution plate is fixed in the flue gas inlet pipe box.

[0013] The utility model has the advantages that the flanging outer edge heat transfer pipe is sealed by the O-ring, the O-ring can buffer vibration, can also adapt to the deformation amount of the heat transfer pipe due to thermal expansion and cold contraction, and does not leak medium after long-term use; the flanging outer edge plays a blocking role in downward movement, and the heat transfer pipe is positioned on the upper tube plate by its own gravity. The flue gas flows forward and reversely, thereby improving the flow rate and the heat transfer coefficient on the flue gas side. The cold air flows through the reverse flow tube bundle and the forward flow tube bundle in turn, thereby increasing the heat transfer temperature difference of the air preheater. The air distribution plate and the flue gas distribution plate improve the uniformity of the fluid entering the tube bundle. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a general structure schematic view of the utility model.

[0015] Figure 2The utility model discloses a side view.

[0016] Figure 3 The utility model discloses the upper and lower tube sheet and heat transfer pipe connecting structure diagram.

[0017] Figure 4 It is the condensate separation pipe box section view.

[0018] The figure numbering: air inlet 1, air inlet pipe box 2, air distribution plate 3, flue gas outlet pipe box 4, flue gas outlet 5, flue gas inlet 6, flue gas inlet pipe box 7, flue gas distribution plate 8, air outlet pipe box 9, air outlet 10, concurrent tube bundle 11, condensate separation pipe box 12, support 13, first condensate outlet 14, second condensate outlet 15, countercurrent tube bundle 16, upper tube sheet 17, lower tube sheet 18, heat transfer pipe 19, O ring 20, liquid discharge plate 21, vortex breaker plate 22. DETAILED DESCRIPTION

[0019] A concurrent countercurrent nonmetallic tube air preheater is supported by the support 13 at bottom. It is equipped with flue gas inlet pipe box 7, condensate separation pipe box 12, flue gas outlet pipe box 4, air inlet pipe box 2, air outlet pipe box 9, flue gas outlet 5, flue gas inlet 6 are equipped at top, air inlet 1, air outlet 10 are at side, flue gas inlet pipe box 7 and condensate separation pipe box 12 are communicated through concurrent tube bundle 11, flue gas outlet pipe box 4 and condensate separation pipe box 12 are communicated through countercurrent tube bundle 16, the lower of concurrent tube bundle 11 and countercurrent tube bundle 16 is same condensate separation pipe box 12, the air inlet pipe box 2 and air outlet pipe box 9 are air flow-through box, the air flow-through box is separated with flue gas outlet pipe box 4, flue gas inlet pipe box 7, condensate separation pipe box 12 through upper tube sheet 17, lower tube sheet 18, and concurrent tube bundle 11 and countercurrent tube bundle 16 pass through upper tube sheet 17, lower tube sheet 18 and make flue gas inlet pipe box 7, flue gas outlet pipe box 4 and condensate separation pipe box 12 communicate. The tube bundle is divided into concurrent tube bundle 11 and countercurrent tube bundle 16, flue gas is cooled from top to bottom in concurrent tube bundle 11, and the flow direction of condensed water and flue gas is same, and the kinetic energy of flue gas is used to drive condensed water, which is beneficial to the discharge of condensed water. Part of uncondensed condensed water is condensed by countercurrent tube bundle 16, and the flow direction of flue gas and condensed water is opposite, which reduces the water content in flue gas, improves the flow speed of flue gas, and improves the separation efficiency of condensed water. Cold air flows through countercurrent tube bundle 16 and concurrent tube bundle 11 in turn, which increases the heat transfer temperature difference of air preheater and improves the heat transfer efficiency of air preheater. The bottom is provided with condensate separation pipe box 12, which is provided with first condensate outlet 14 and second condensate outlet 15. The condensate separation pipe box 12 and the air preheater pipe box are integrated structure, and new condensate collecting device is not needed, which improves the collection efficiency of condensed water.

[0020] The vertical arrangement of the plurality of heat transfer pipes 19 constitutes the parallel flow tube bundle 11 and the counter flow tube bundle 16, the heat transfer pipe 19 is a non-metal pipe and a non-equal-diameter pipe, one end of which has a flanged edge, the flanged edge is in contact with the outer surface of the upper tube plate 17, the heat transfer pipe 19 is sealed between the upper tube plate 17 and the lower tube plate 18 through the O-shaped ring 20, and the side wall of the pipe hole of the upper tube plate 17 and the lower tube plate 18 is provided with an annular groove for accommodating the O-shaped ring 20. The O-shaped ring 20 arranged on one heat transfer pipe 19 is provided with two O-shaped rings 20 on the upper tube plate 17 and the lower tube plate 18. The O-shaped ring is made of a corrosion-resistant high polymer material and has elasticity, and the double O-shaped ring sealing structure enables the heat transfer pipe 19 to freely stretch and retract, thereby solving the problem of thermal expansion of the heat transfer pipe 19 and the shell caused by vertical installation of the equipment. The flanged edge of the heat transfer pipe 19 constitutes a suspension structure with the upper tube plate, so that the heat transfer pipe is positioned on the upper tube plate by relying on its own gravity.

[0021] The heat transfer pipe 19 is made of PP-GR or PPS-GR material. The PP-GR or PPS-GR material is a modified material of PP, which has high toughness, high wear resistance, and also has a relatively high thermal conductivity, and is an ideal heat transfer pipe for a low-temperature air preheater. The flue gas inlet pipe box 2, the flue gas outlet pipe box 4, the condensate separation pipe box 12 and the tube plate of the tube bundle are all made of SMO254 composite plate, which ensures the corrosion resistance of the air preheater and improves the economy of the equipment.

[0022] The condensate separation pipe box 12 is provided with a drain plate 21 on the bottom surface, the drain plate 21 is inclined and inclined to the middle condensate outlet, and the condensate is collected in the condensate outlet through the drain plate 21, thereby reducing the residue of the condensate in the condensate separation pipe box.

[0023] The drain plate 21 is fixed with a vortex breaker 22 near the first condensate outlet 14 and the second condensate outlet 15, which destroys the liquid vortex.

[0024] Since the flue gas and air inlet cross section of the utility model is large, the air distribution plate 3 is fixed in the air inlet pipe box 2, and the flue gas distribution plate 8 is fixed in the flue gas inlet pipe box 7. The air distribution plate 3 and the flue gas distribution plate 8 improve the uniformity of the air and flue gas entering the air preheater tube bundle, and improve the heat transfer efficiency of the air preheater.

[0025] Gas flow heat exchange process: flue gas enters flue gas inlet pipe box 6 from flue gas inlet 5, is uniformly distributed by flue gas distribution plate 8, enters the parallel flow tube bundle 11, is cooled and condensed by air outside the tube, enters the condensate separation pipe box 12, the condensed liquid is discharged from the first condensate outlet 14 and the second condensate outlet 15, the flue gas enters the counter flow tube bundle 16 from the condensate separation pipe box 12, continues to exchange heat and cool with air, is condensed, the condensed liquid relies on gravity to continue to enter the condensate separation pipe box 12, and is discharged from the first condensate outlet 14 and the second condensate outlet 15, the cooled flue gas reaches the flue gas outlet 5 from the flue gas outlet pipe box 4. Air enters the air inlet pipe box 2 from the air inlet 1, is uniformly distributed by the air distribution plate 3, enters the counter flow tube bundle 16 and the parallel flow tube bundle 11 in turn, the air heated by the flue gas inside the tube reaches the air outlet 10 from the air outlet pipe box 9.

Claims

1. A non-metallic air preheater with parallel flow and counter flow, which is provided with a flue gas inlet header (7), a condensate separation header (12), a flue gas outlet header (4), an air inlet header (2), an air outlet header (9), a flue gas outlet (5), a flue gas inlet (6) arranged at the top, an air inlet (1), an air outlet (10) arranged at the side, a parallel flow tube bundle (11) and a counter flow tube bundle (16) below the same condensate separation header (12), an air flow passage between the air inlet header (2) and the air outlet header (9), the air flow passage being separated from the flue gas outlet header (4), the flue gas inlet header (7) and the condensate separation header (12) by an upper tube plate (17) and a lower tube plate (18), the parallel flow tube bundle (11) and the counter flow tube bundle (16) passing through the upper tube plate (17) and the lower tube plate (18) to communicate the flue gas inlet header (7), the flue gas outlet header (4) and the condensate separation header (12), the parallel flow tube bundle (11) and the counter flow tube bundle (16) being composed of a plurality of vertical heat transfer tubes (19), characterized in that: The heat transfer pipe (19) is a non-metal pipe and a non-equal-diameter pipe, one end of which has a flanged edge, the flanged edge is in contact with the outer surface of the upper tube plate (17), the heat transfer pipe (19) is sealed with the upper tube plate (17) and the lower tube plate (18) through an O-shaped ring (20), and the side wall of the pipe hole of the upper tube plate (17) and the lower tube plate (18) is provided with an annular groove for accommodating the O-shaped ring (20).

2. A non-metallic tube air preheater of the parallel and counter flow type according to claim 1, characterized in that: Two O-shaped rings (20) are arranged on one heat transfer pipe (19).

3. The non-metallic air preheater according to claim 1, wherein: The condensate separation pipe box (12) is provided with a first condensate outlet (14) and a second condensate outlet (15) at the bottom, and the air preheater is supported by a support (13) at the bottom.

4. The non-metallic air preheater according to claim 1, wherein: The heat transfer pipe (19) is made of PP-GR or PPS-GR material.

5. A non-metallic tube air preheater of the reverse-flow type according to claim 3, characterized in that: The bottom surface of the condensate separation pipe box (12) is provided with a liquid discharge plate (21), the liquid discharge plate (21) is inclined and arranged towards the middle condensate outlet.

6. A non-metallic tube air preheater of the reverse-flow type according to claim 5, characterized in that: A vortex breaker (22) is fixed at the position of the liquid discharge plate (21) close to the first condensate outlet (14) and the second condensate outlet (15).

7. The non-metallic air preheater according to claim 1, wherein: An air distribution plate (3) is fixed in the air inlet pipe box (2), and a flue gas distribution plate (8) is fixed in the flue gas inlet pipe box (7). An air distribution plate (3) is fixed in the air inlet pipe box (2), and a flue gas distribution plate (8) is fixed in the flue gas inlet pipe box (7).

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