Development of Direct Contact Condensation Multistage Flash Distillation Process: Phase 3A Page: 6
v, 48, [4] p. : ill.View a full description of this report.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Wrightsville Beach city water as make-up to the fresh water side of the circuit.
The remaining runs were made with steam condensate. The final runs (23 & 24)
were made after removal of scale from the outside surfaces (sea water side) of
the tubes with acid. The tubes were visibly clean after this operation. Although
there is considerable scatter in the heat transfer coefficient values, no clear
cut trend is indicated. The fact that the scale removal treatment did not increase
the measured heat transfer coefficients is an indication that the scale had not
adversely affected heat transfer. No scale formation inside the tubes was
observed during the six month test with condensate flowing through them. This
was indicated by the relatively constant pressure drop during the test period,
and confirmed by examination of the tubes after termination of the test.
A detailed examination of the entire system was conducted at the time of
shutdown. The tubes were found to be in excellent condition with no evidence
of leaks or distortion. Total elongation of the tubes was found to be in the
range of 1-1/2 to 2 inches. The elongation was measured while the tubes were
subjected to the normal operating tensile force of 0. 83 lb per tube in addition
to the internal pressure stress.
As would be expected in an untreated system heated to 2000F, some scale
deposition occurred on the sea water side. The deposition was almost entirely
on the upper surfaces of the tubes and the heaviest concentrations were found
at the sea water outlet (hottest) end of the tank. An appreciable amount of
scale had flaked off the tubes during the operating period and this material
covered the bottom two rows of tubes. After shutdown these deposits were
removed, weighed and analyzed. They totaled 28 lbs, 95 to 97% of which was
calcium or magnesium carbonate with the remainder very fine silt. The sea
water tank coating (Wisconsin Protective Coating Corporation Plasite #7155)
had deteriorated somewhat, permitting corrosion of the carbon steel tank wall
to occur in a number of places. The most severe attack occurred at weld
zones where apparently pin holes in the coating permitted the hot sea water to
reach the underlying metal.
Carbon steel tubing clamps, which had been dipped in Plasite coating and
cured before use, also suffered some corrosion. However, only one of the 90
clamps actually failed. Fortunately, the two neoprene O-rings used as a gasket
between the metal clamp and the thin plastic tube were still intact on this tube
connection, forcing the Tedlar tube into grooves on the metal nozzle so that no
leakage occurred. During disassembly it was observed that all of the Tedlar
tubes were quite tight on the nozzles and required considerable force for
removal even after removal of clamps and O-rings.
After completion of all tests, the system was placed in condition for
temporary storage. The sea water loop was flushed with fresh water and both
fresh and sea water loops were then filled with clean fresh water to which
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Kohl, A. L.; Shimazaki, T. T.; Suratt, W. B. & Westerman, S. Development of Direct Contact Condensation Multistage Flash Distillation Process: Phase 3A, report, January 1971; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc11770/m1/13/: accessed May 6, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.