Refrigeration – Processes – Congealing flowable material – e.g. – ice making
Patent
1996-05-08
1998-11-17
Tapolcai, William E.
Refrigeration
Processes
Congealing flowable material, e.g., ice making
62293, F25D 300
Patent
active
058361677
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The field of this invention relates to freezing plugs in pipe, and in particular, to freezing plugs in large and subsea pipe.
BACKGROUND OF INVENTION
Pipe freezing is an established technique for effecting the temporary isolation of a section of a pipe. Fluid in a line, which may include water, oil, hydrocarbons or gel and/or which may involve a strategically placed substance or pig, is frozen by surrounding the pipe with a cooling medium. Current industry practice follows the cryogenic fluid system for performing a pipe freeze. The cryogen typically comprises a liquid nitrogen or carbon dioxide. In the cryogenic system compressed fluids (or solids) at very low temperatures are supplied to a job in tanks, allowed to vaporize to absorb heat and are then vented to the atmosphere. For each job, a sufficient supply of the cryogen, in liquid or solid form, must be on hand to carry out the freeze. Certain cryogenic fluids, such as liquid nitrogen or carbon dioxide, readily meet the needs of vaporizing at very low temperatures and being generally cost effective and transportable. The discharge of these fluids, when consumed, is environmentally acceptable. The bulk of the tanks required to assure an adequate supply of the cryogen at the job, and the care, tending and human supervision required to assure that such tanks remain operational, have not been regarded as imposing unacceptable limitations. Taking into account cost, availability, transportability and time, the cryogenic fluid system has been accepted and adopted as offering the clearly superior cooling system for performing isolated freezes at unpredictable, and possibly remote, locations.
"Guidelines to Good Practice in Pipe Freezing", Version PD 1, January 1990, Corrections June 1991, (C) U. of S. & D. A. W. 1990, c:pt1CvPpip, comprehensively summarized, as of the early 1990's, the state of the art of the technology of pipe freezing. The following quotes from pages 4 and 5 of the document are instructive. the pipe and its contents can be reduced to achieve a freeze. For small diameter pipes, freon aerosols have been used by plumbers, but, as the use of freon is now considered an environmental hazard, this practice is now obsolete. Somewhat larger diameters can be handled by the `Jet-Freezer` type of equipment that uses liquified carbon dioxide. For larger pipes, the most common technique is to attach a jacket to the outside of the pipe and to fill the resultant enclosed space with either liquid nitrogen or a mixture of solid carbon dioxide and a heat-exchange fluid. easily transported, stored and transferred to the freezing jacket. Furthermore, its boiling point of 77 K (-196.degree. C.) is far below the temperature required to freeze water and many other fluids and high heat extraction rates are thus possible due to this large degree of supercooling. It is also the only convenient way to obtain temperatures low enough to freeze crude and many refined oils. The circumstances in which the use of liquid nitrogen is essential are listed in the flowsheet, Factors Dictating the Use of Liquid Nitrogen. ferritic steels which are well below their tough-to-brittle transition at the boiling point of liquid nitrogen. Furthermore, the direct impingement of liquid nitrogen on the pipe wall can create large temperature gradients and thermal stresses in the pipe wall. For these and other reasons, it is often necessary to use a different cooling technique, the so-called controlled temperature freeze. The flow sheet entitled Factors to be Considered for Use of a Controlled Temperature Freeze addresses these points. fluid, such as isopropanol or methanol, is used to surround, and be in contact with, the pipe wall. This fluid is in turn cooled either by the direct addition of solid carbon dioxide, by the controlled supply of liquid nitrogen, or by the circulation of a refrigerant through a coil immersed in the fluid. Cooling times are much longer using this technique, but fine control can be maintained over both the cooling rate and minimum tempe
REFERENCES:
patent: 2483082 (1949-09-01), Young et al.
patent: 2566865 (1951-09-01), Wingerter
patent: 2572555 (1951-10-01), Young et al.
patent: 2972239 (1961-02-01), Vasby
patent: 3041850 (1962-07-01), Nunn
patent: 3196627 (1965-07-01), Swenson
patent: 3386495 (1968-06-01), McCurdy et al.
patent: 3498071 (1970-03-01), Tremont
patent: 3559423 (1971-02-01), Scheidler
patent: 3623337 (1971-11-01), Tremont
patent: 3695301 (1972-10-01), Pittman
patent: 3742723 (1973-07-01), Grise
patent: 3827282 (1974-08-01), Brister
patent: 3905424 (1975-09-01), Elwood et al.
patent: 3926006 (1975-12-01), Brooks et al.
patent: 4112706 (1978-09-01), Brister
patent: 4220012 (1980-09-01), Brister
patent: 4224804 (1980-09-01), Haas
patent: 4267699 (1981-05-01), Bahrenburg
patent: 4309875 (1982-01-01), Radichio
patent: 4314577 (1982-02-01), Brister
patent: 4370862 (1983-02-01), Brister
patent: 4416118 (1983-11-01), Brister
patent: 4428204 (1984-01-01), Brister
patent: 4433556 (1984-02-01), Brady
patent: 4441328 (1984-04-01), Brister
patent: 4463572 (1984-08-01), Brown, Jr.
patent: 4492095 (1985-01-01), Brister
patent: 4522041 (1985-06-01), Menzel
patent: 4944161 (1990-07-01), Van Der Sanden
patent: 5016446 (1991-05-01), Fiedler
patent: 5548965 (1996-08-01), Chen et al.
Bowen et al., "Recent Developments in Pipe Freezing," presented at I. Mech. E. Conference in Feb. 1989.
CoPipe Systems Limited, Advertisement brochure, dated 1996 (approximate).
Monk, M.C., "Examincation Report under section 18(3)," U.K. Patent Office, dated Dec. 23, 1997.
Monk, M.C., "Observations under Section 21," U.K. Patent Office, dated Dec. 22, 1997.
Newman & Saunders, "Pipeline Isolation Techniques," Pipeline & Gas Journal, pp. 30-37, 1991.
Shell Standard EM/070, dated Sep. 1993.
Shell Standard EM/071, dated Jan. 1994.
Wigley et al., "Guidelines to Good Practice in Pipe Freezing," dated Jan. 1990, corrected Jun. 1991.
Oil & Gas Journal, Michael J. Nelson, Exxon Co. U.S.A. New Orleans, "Freeze plug proves safe, economical in riser repair". May 1995.
Proceedings Of The Institute Of Acoustics, vol. 10, Part 2, p. 681 "An Acoustic Method For Detecting Ice Plug Formation in Cryogenic Pipe Freezing". 1988.
Offshore Engineer Scotland Review, p. 33, Jul. 1994, "Subsea tie-in plays it cool".
University Of Southampton, Department of Mechanical Engineering, Version PD 1, Jan. 1990, "Guidelines to Good Practice in Pipe Freezing".
Nowsco Newsletter Article "Pipe Freeze Achieved on Wellhead" 1995.
PCT International Search Report.
Clouston Stuart D.
Goodwin Paul S.
Nowsco Well Service Ltd.
Shaper Sue Z.
Tapolcai William E.
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