CN201203140Y - Shell-type air preheater - Google Patents

Abstract

The plate-shell type air preheater proposed by the utility model is composed of a plurality of metal heat transfer plates arranged in parallel; Downward right-angled flange (7), said right-angled flange also has outward 90° folded edge to form the connection surface (5) of welding connection between the plates; downward or upward right-angled by a piece of heat transfer plate The joint surface (5) of the folded edge and the joint surface (5) of the upward or downward right-angle folded edge of another heat transfer plate are joined together to form a channel unit (4), and the upper and lower heat transfer plates of the channel unit pass through The connecting surfaces of the upward or downward right-angle folded edges are respectively connected with other heat transfer plates to form two channel units. Multiple heat transfer plates are connected by the above connection methods to form a group of multiple channel units. The multiple channels formed The flow directions of adjacent channel units in the unit are perpendicular to each other; multiple groups of channel units are connected together to form a plate-shell air preheater.

Description

Shell-type air preheater

technical field

The utility model belongs to the air preheater technology and mainly proposes a plate-shell type air preheater, which can be applied to the waste heat recovery of flue gas in refinery heating furnaces, power plant boilers, and steelmaking furnaces in steel mills, and can also be used in printing and dyeing, Waste heat recovery of grain and other drying hot stoves.

Background technique

With the development of the economy, the requirements for environmental protection and energy saving are increasing day by day, requiring enterprises to reduce energy consumption and temperature of exhausted flue gas during production. The use of an air preheater to recover the waste heat in the flue gas is the most direct and simplest method. In the 1960s and 1970s, the air preheaters mostly used by enterprises were of tube bundle type; in the 1980s and 1990s, most enterprises used heat pipe air preheaters. The disadvantages of the tube-bundle air preheater are: 1. The heat transfer coefficient is low, which causes the total heat transfer coefficient of the preheater to become smaller, and the heat exchange area required to recover the same heat is larger. 2. Huge volume. As mentioned above, the smaller the total heat transfer coefficient, the larger the required heat exchange area. Coupled with the structural characteristics, the volume of the preheater is very large. The disadvantages of the heat pipe air preheater are: 1. The operating temperature is limited, and the molten steel heat pipe structure is generally used. Excessive heat transfer will cause the heat pipe to explode and cause an accident. 2. The reliability is poor, because the manufacturing process of the molten steel heat pipe is complicated, the steel pipe needs to be pickled and alkali washed, and then pure water is added and vacuumized. Any problem in any link will cause the water in the pipe to evaporate, produce non-condensable gas, and cause The vacuum degree drops, causing the heat pipe air preheater to fail. 3. It is easy to accumulate dust. The heat pipe is generally placed close to the level in the device. At the same time, the fins with a spacing of 2-3 mm are wound on the pipe, which is easy to scale and accumulate dust. Due to the scale and dust accumulation, the heat transfer of the heat pipe The coefficient decreases, resulting in a decrease in the waste heat recovery capacity of the heat pipe air preheater. 4. The cost is high. Due to the complicated manufacturing process of the heat pipe, the cost of the heat pipe air preheater is relatively high.

Contents of the invention

The purpose of this utility model is to propose a plate-shell air preheater, which has the disadvantages of high heat transfer performance, not limited by flue gas temperature, small volume, simple structure and low cost.

The utility model adopts the following technical solutions to complete the invention task: a plate-shell air preheater, which is composed of a plurality of metal heat transfer plates arranged in parallel; the heat transfer plate is a square, and its two sides have upward right-angle folds , the other two sides have downward right-angle folds, and the said right-angle folds also have outward 90° folds to form the joint surface of the welding connection between the plates; two heat transfer plates are connected to form a channel unit , that is, the connecting surface of one heat transfer plate with downward or upward right-angle folding and the connecting surface of another heat transfer plate with upward or downward folding at right angles are joined together to form a channel unit. The upper and lower transmission of the channel unit The heat plate is connected with other heat transfer plates to form a channel unit through its upward or downward right-angle folded connection surface, and multiple heat transfer plates are connected by the above connection method to form a group of multiple channel units. The flow directions of adjacent channel units in the channel unit are perpendicular to each other; multiple groups of channel units are connected together to form a plate-shell air preheater.

When in use, the preheater is connected to the flue gas pipe and the air pipe respectively, and the flue gas inlet and the air inlet are perpendicular to each other, wherein the odd-numbered channels are the flue gas channels or the air channels, and the even-numbered channels are the air channels or the flue gas channels, that is, the flue gas channels They are arranged at intervals with the air channel and are perpendicular to each other. High-temperature flue gas enters multiple parallel flue gas passages of the plate and shell preheater evenly through the flue gas pipe, and low-temperature air enters multiple parallel air passages of the preheater evenly, and heat is transferred through the heat transfer plate, finally realizing the reduction of smoke. The purpose of increasing the exhaust temperature of the gas and increasing the temperature of the air outlet.

The plate-shell type air preheater proposed by the utility model has simple and reasonable structural design and good heat transfer performance.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a structural schematic diagram of the heat transfer plate in the utility model.

Fig. 3 is a schematic diagram of a channel unit formed by connecting two heat transfer plates.

In the figure, 1. outer frame, 2. heat transfer plate, 4. channel unit, 5. connection surface, 6. upward folding, 7. downward folding.

Detailed ways

The utility model embodiment is described in conjunction with accompanying drawing:

As shown in Figure 1, the plate-shell air preheater of the utility model is composed of a plurality of metal heat transfer plates arranged in parallel. Vertical, that is, the flue gas channel and the air channel are arranged at intervals and are perpendicular to each other. As shown in Figure 2, the heat transfer plate 2 is a square plate stamped from a cold-rolled plate with a thickness of 1.2 to 1.5mm. 6. The upward and downward folds have an outward 90° fold to form a joint surface 5 that is welded to another heat transfer plate. As shown in Figure 3, every two heat transfer plates are connected to form a channel unit, that is, the connecting surface 5 of the front and rear sides of one of the heat transfer plates is folded upward 6 and the left and right sides of the other heat transfer plate are folded downward 7 The joint surface 5 of the joint is joined together by welding to form a channel unit 4, and the two heat transfer plates are respectively connected with other heat transfer plates in this connection to form two channel units; thus, multiple heat transfer plates are connected to form a A group of multiple channel units; the flow directions of adjacent channel units in multiple channel units are perpendicular to each other; multiple groups of channel units are connected to form a plate-shell air preheater, which is based on the required heat transfer load and the structural size of the heating furnace Multiple groups of channel units are combined and connected. In order to increase the heat transfer effect and prevent the thermal deformation of the heat transfer plate, V-shaped deflectors can be added to each layer of channels. At the same time, considering the overall strength requirements, angle steel is used as the plate and shell type. The frame of the air preheater. When in use, the shell-and-plate air preheater can be connected to the flue gas pipe and the air pipe respectively through flanges, wherein the inlet of the flue gas pipe and the inlet of the air pipe are perpendicular to each other.

Claims (1)

1. A plate-shell type air preheater, characterized in that: the air preheater is composed of a plurality of metal heat transfer plates arranged in parallel; the heat transfer plate (2) is a square, and its two sides have upward Right-angle folds (6), the other two sides have downward right-angle folds (7), and described right-angle folds also have outward 90° folds to form the connecting surface (5) of welding connection between plates; Two heat transfer plates are connected to form a channel unit, that is, the joint surface (5) of one heat transfer plate is folded downward or upward at a right angle and the joint surface (5) of the other heat transfer plate is folded upward or downward at a right angle. ) to form a channel unit (4), and the upper and lower heat transfer plates of the channel unit are respectively connected with other heat transfer plates to form two channel units through their upward or downward right-angle folded connecting surfaces. The sheet heat transfer plate is connected by the above connection method to form a group of multiple channel units, and the flow directions of the adjacent channel units in the multiple channel units formed are perpendicular to each other; multiple groups of channel units are connected together to form a plate-shell air preheater. heater.

Images