Twisted tube heat exchanger gives more advantages as compared to traditional shell & tube exchanger with straight tubes in oil refining, chemical, petrochemical and energy and other application
1.Increased heat transfer efficiency with up to 40 %. For a high viscosity fluid on the tube side, the improvement can be larger than 100 %.
2.Turbulent flow inside tubes also at low flow rates
3.Less fouling on both the tube and shell side, due to the scrubbing effect inside the tubes and elimination of areas of low velocity on the outside, i.e. where the baffle plates contact the inside of the shell.
4.Elimination of vibration damages since the twisted tubes support each other along their whole lengths.
5.Lower pressure loss on the shell side since the baffle plates could be omitted. Lower pressure loss also on the tube side, since the heat exchanger can be made shorter and the need for a multi pass design decreases.
In oil refining, chemical, petrochemical and energy and other application more than 85% of the heat exchanger used is the traditional shell and tube heat exchanger. For a wide variety of heat transfer requirements, this technology can be widely used because of the fact that the technology is a low-cost technology after the actual verification. However, the technology also has its limitations, its pressure drop is large, the formation of dead zone due to low flow velocity in the baffle plate, which may cause pollution and corrosion of equipment. And the vibration of the tube, which may cause the equipment failure. Recent innovation and development of a new technology, known as the spiral flat tube technology, can overcome the limitations of the traditional technology, in addition, through tube heat transfer can provide a superior total heat transfer coefficient.
The production process of the twisted flat tube produced by our company ensures that the thickness of the pipe wall is kept unchanged and no more than the yield point of the material. Both ends of the end of the tube end is still round, which is conducive to the tube plate connection. The material and diameter of the pipe is selected according to the need.
The twisted flat pipe is a kind of heat exchanger tube which was first proposed by Allares company of Switzerland and improved by American Brown company (Tom Brown Corp of Houston). Because of the unique structure of the pipe, the fluid in the pipe is in a spiral flow, causing turbulence. The experiment shows that the twisted flat tube heat transfer coefficient is usually higher than the ordinary endometrial tube increased at low Reynolds number was the most, up to 2 - 3 times; with the increase of Reynolds number, usually also can increase the heat transfer coefficient is above 50%.
The process is to flatten the tube and twist it into a spiral. When the tube is worn, the tube bundle is arranged on the same side, and the tube bundle has no supporting parts, but the contact point of the spiral line outside the spiral outer edge of the spiral flat pipe is mutually supported. In the pipe, spiral flow increases the turbulence degree, thinning of the main thermal resistance as the heat stagnation layer thickness, the pipe heat transfer can be enhanced. In the case of the shell, the flow between the spiral tubes is also spiral, and the fluid moves in the course of the centrifugal force to change the speed and direction periodically, thus strengthening the longitudinal mixing of the fluid. Coupled with the fluid through the spiral pipe adjacent contact point formed from the wall of the wake, enhance the turbulence of the fluid itself, destroying the fluid heat transfer boundary layer on the pipe wall, so the heat transfer in the shell was intensified. Tube in tube heat transfer and strengthen the results of the heat transfer effect than ordinary shell and tube heat exchanger has greatly improved, especially on the viscosity of the fluid, one or both sides of the heat exchange process of a stagnant flow, the effect is particularly prominent.