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A Simple Twist Of Fate

Theodoros Albanis and Evdoxia Kladopoulou, Hellenic Petroleum S.A., Greece, and Blazo Ljubicic and Marco Fazzini, Koch Heat Transfer Company S.r.l, Italy, recount how a heat exchanger for texas tower feed/effluent applications aided the upgrade project of the Hellenic Petroleum Refinery at Thessaloniki.

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Design and Application of Twisted Tube® Heat Exchangers

Conventional baffled shell-and-tube exchangers, while having an excellent record of acceptance and functionality, have some notable limitations. In particular, the shell-side path is wasteful on pressure drop, limits maximum thermal effectiveness and encourages dead spots where fouling or corrosion may occur. This paper describes an advanced shell-and-tube design, known as the Twisted Tube® Heat Exchanger, which is inherently able to overcome these limitations in addition to providing the further advantages of tube-side enhancement and good tube support to reduce susceptibility to vibration. The paper compares the Twisted Tube® exchanger with conventional advanced designs.

Twisted Tube® Heat Exchangers: Technology and Application

This article was presented at the November 9th, 1999 "Latest Advances in Offshore Processing" conference in Aberdeen, Scotland. Heat exchangers are usually classified by the compactness factor in m2/m3 and it is generally accepted that values greater than 700 m2/m3 characterize compact equipment. Although shell-and-tube exchangers can have high compactness factor, compact heat exchangers are often referred to as non-tubular devices. This paper describes an advanced shell-and-tube heat exchanger using twisted tubes. Recent advances in the range of design and operational reliability have made twisted tube heat exchangers attractive in various industries, including offshore application. Taking into account size and convenience considerations, these exchangers can be cost-effective in a wider range of applications than the niches currently being used in the process industry.

Testing of Twisted Tube® Exchangers in Transition Flow Regime

This paper describes testing of advanced shell and tube design with Twisted Tube® technology. Its performance has been tested under single-phase, fully developed, transition flow conditions. Subject to design constraints and based on specific optimization requirements, several configurations were tested, each test examining heat transfer and pressure drop for the particular heat exchanger. It was shown that overall heat transfer and pressure drop increase with a smaller tube twist pitch to diameter ratio, and that these exchangers have specific advantages and characteristics, previously open only to plate exchanger users. Twisted tubes increase the level of mixing and promote turbulence in the low Reynolds number range, on both tube-side and shell-side of the tubes.

Reboiler Revamps

This article appeared in the September 2006 issue of The International Journal of Hydrocarbon Engineering, it discusses the application of Twisted Tube® technology in kettle reboiler revamps at the Ju'Amyad gas plant.

Download this file (ReboilerRevamps.pdf)Reboiler Revamps [ ] 605 kB