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Shell-and-tube continuous helical baffle heat exchanger

2014-09-23 10:21

The so-called continuous spiral baffle heat exchanger is to cancel the arcuate baffle plate used to control the direction and flow rate of fluid movement in the shell side of the shell-and-tube heat exchanger, replaced by a continuous spiral baffle plate, which is actually called a spiral guide plate. The continuous spiral guide plate in the shell makes the fluid move along a continuous, closed spiral channel with no change in the cross-sectional area of the flow passage, that is, the fluid moves in the whole process of the shell, and the motion trajectory is a stable spiral line. This drastically changes the zigzag reentrant flow regime of the shell-side fluid in the arcuate baffle heat exchanger. This is a revolution in the fluid motion state of the shell and tube heat exchanger shell side. And now more advanced, and widely used 1/4 spiral baffle plate heat exchanger, it is by the transformation of a certain angle of four fan-shaped baffle composed of a pitch, that is, in a quadrant to put a fan-shaped baffle plate, fan-shaped baffle The distance between the plates is 1/4 pitch. This spiral baffle heat exchanger is formed by an approximate spiral channel.

Figure 1 is a partial photograph of a semi-finished product of a continuous spiral baffle tube bundle, and Figure 2 is a partial photograph of a semi-finished product of a 1/4 spiral baffle tube bundle. Comparing the two photos, it can be clearly seen that the two kinds of spiral guide plate heat exchanger tube bundle are different in structure. The continuous spiral guide plate heat exchanger has no short circuit problem, higher heat transfer efficiency and greater operating elasticity.

  

管壳式连续螺旋折流板换热器

 

The trajectory of the fluid in the shell side of the traditional arcuate baffle heat exchanger is Z-shaped, the direction and velocity of the fluid are changing periodically, and there is a blind zone of fluid movement. The motion trajectory of the shell side fluid of the continuous spiral guide plate heat exchanger is a spiral line, the motion speed does not change, and the flow rate is high, the pressure drop is small, and there is no movement blind area. Experiments show that when the fluid velocity of the shell side of the continuous spiral plate heat exchanger is twice the fluid velocity of the arcuate baffle plate, the pressure loss is much less than the pressure loss of the arcuate baffle plate. Therefore, the flow rate of the shell of the continuous spiral plate heat exchanger can be designed to be very large. When the fluid flow rate is large and the pressure loss is small and there is no flow blind area, the continuous spiral guide plate heat exchanger has the following advantages:

First, the heat transfer efficiency is greatly improved, and the energy saving effect is obvious. The large heat transfer coefficient at unit pressure drop is an obvious feature of the continuous spiral guide plate heat exchanger. The heat transfer coefficient (h/Δp) at the unit pressure drop of the shell side is used as a measure of the overall performance of the heat exchanger, and the continuous spiral guide plate heat exchanger is much better than the arcuate baffle heat exchanger. Figure 3 is a schematic diagram of the relationship between the pressure drop and the heat supply system based on our test. When the flow rate is higher, the heat transfer efficiency of the continuous spiral guide plate heat exchanger is high, and the characteristics of low pressure loss will be more obvious.

  

管壳式连续螺旋折流板换热器

 

Second, no precipitation, no blockage. If the flow rate is high and there is no movement blind area, there will be no sediment.

Third, anti-scaling, the most effective way to prevent scaling is to make the high flow rate, and the flow rate of high pressure drop is the biggest feature of continuous spiral guide plate heat exchanger, high flow rate can effectively slow down the formation of scaling on the wall of the heat exchange tube, and even avoid scaling. When there is little or no scaling, the heat exchange efficiency can be improved, and the cleaning cycle can be extended to ensure the long-term operation of the device and reduce the maintenance cost. Fig. 4 is a photo of scaling outside the heat exchanger tube with bow-shaped baffle plate in Lianyungang Soda Plant, and Fig. 5 is a photo of scaling outside the heat exchanger tube with continuous spiral baffle plate in Lianyungang Soda Plant. The difference of scaling thickness can be clearly seen from the two photos;

Fourth, anti-vibration, because in a heat exchanger tube bundle in the guide plate is a continuous whole, the heat exchange tube has no support span is small, the fluid movement is stable and pulse-free, so it can effectively prevent the vibration of the heat exchange tube, and the continuous spiral guide plate heat exchanger is also very suitable for occasions prone to vibration.

Fifth, the continuous spiral baffle plate heat exchanger is more elastic than the 1/4 spiral baffle plate operation. When the flow rate is low, the problem of leakage short circuit in the center of the 1/4 spiral baffle heat exchanger is particularly prominent, and the heat exchange efficiency is greatly reduced. The continuous spiral spiral guide plate heat exchanger does not exist.