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full-length tuJM TQVMZ[ QV = ; ZMÅVMZQM[ was quite new at that time, says Silver- man. Since the technology was proven in other industries and the use of alloy tube liners with CS tubes was seen as a more cost-effective solution than installing solid C-276 finned tubes, the decision was made to install full-length C-276 tube liners when the overhead condenser was retubed with new CS tubes in 2006. The mitigation strategy worked and today, six years later, the tubes in the crude unit W^MZPMIL ÅV NIV KWVLMV[MZ ZMUIQV KWZ- rosion free.
The overhead condenser tube liner
XZWRMK\ I\ \PM +IZ[WV ZMÅVMZa _I[ ]VQY]M at the time for several reasons, says Terry Quinn, West Coast regional manager for CTI Industries (Orange, Connecticut), the company that supplied and installed the tube liners. For one thing, liners are typically installed in heat exchanger tube bundles where tube plugging has ex- ceeded the heat exchanger design speci- ÅKI\QWV[ Ja
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where nondestructive testing methods M[\QUI\M M`Q[\QVO \]JM _ITT TW[[ WN
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more. Liners are commonly installed in previously plugged tubes to restore them to service. )\ \PM +IZ[WV ZMÅVMZa \PM \]JM TQVMZ[
were installed in two tube bundles that had been completely retubed with new ;) ! ÅVVML \]JM[ ;QT^MZUIV M`XTIQV[ that it was faster and more cost effective to replace all the CS tubes and then in- stall protective liners rather than clean and prepare existing tubes for liner inser- tion. There is always a risk that cleaning corroded heat exchanger tubes would cause them to perforate and fail, Silver- man says, which would require tube re- placement anyway and add time to the XZWRMK\ 1V I ZMÅnery, he remarks, pro- longing the duration of the plant turn- around by even one extra day is expen- sive and could be more costly than the
NACE International, Vol. 51, No. 4
price to retube the heat exchanger. Ad- ditionally, installing liners in new tubes _QTT UI`QUQbM PMI\ \ZIV[NMZ MNÅKQMVKa
that the CS tubes were slightly thinner and new, the unit didn't experience any cooling issues after start-up. For this project, the two tube bundles ! \]JM[ XMZ J]VLTM \PI\ IZM U TWVO IVL QV UU QV
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(3.04 mm) and were installed by a local company. The C-276 tube liners are 42- N\
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The liner installation was also unique as well as challenging, Quinn comments. The liners were inserted in situ into new parent tubes that were 40 ft off the ground, which required the use of a crane, scaffolding, and the inlet catwalk. The tube liners were loaded into a cradle NI[PQWVML NZWU I N\ U LQIUM\MZ pipe that had been cut in half lengthwise; lifted by crane until they were adjacent to the catwalk; and then hand fed from the cradle to the tubesheet and inserted into the new tubes. Quinn notes that Silverman's solution for lifting the tube liners up to the heat exchanger tube J]VLTM[ _I[ [W MNÅKQMV\ \PI\ \PM \QUM ZM- quired to complete the project, as com- pared to the time estimated in the original job scope, was reduced by a full shift. Once the liners were in place, a por-
table hydraulic pump located on the catwalk was used to expand the tubes NZWU \PMQZ WZQOQVIT 7, WN f QV
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! UU NWZ I UM\IT Continued on page 16
April 2012 MATERIALS PERFORMANCE 15
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