Online pigging system and method

Abstract

The disclosure provides a heat transfer system having a tubing coil for heating fluid flowing therein, where the tubing coil can be pigged (descaled) while operationally online, instead of offline. The online system uses an assembly of valves and associated equipment to connect to a pig launcher and pig receiver while the system is online. A valve opens and the pig launches into the flow stream under pressure through the valve and travels along the tube with the fluid. The system continues to produce heated fluid with the pig in the flow path. A pig receiver receives the pig after the pigging, and then is isolated from the flow path of the heated fluid by another valve. The pig launcher, pig receiver, and pig are removed, and this process is repeated for any other passes in the tubing coil.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]Not applicable.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicable.REFERENCE TO APPENDIX[0003]Not applicable.BACKGROUND OF THE INVENTION[0004]1. Field of the Invention[0005]The disclosure relates generally to a method for cleaning heat transfer systems, and more specifically, to heat transfer systems having tubing coils for passing fluid therethrough to be heated by a heat source.[0006]2. Description of the Related Art[0007]Heat transfer systems having tubing coils are used in a number of applications. A heat source transfers heat through a heat exchanger generally having a chamber and a tubing coil therein. The heat source heats the tubing coil that in turn heats a fluid flowing through the tubing coil. The heat source can be, for example, a fuel combustion burner, radiant heat source, including infrared, hot fluids, including gases, or exhaust fluids from a turbine or engine, or other waste heat fluids. F...

AI Technical Summary

Benefits of technology

[0018]Thus, there remains a need for an improved system and method for

Problems solved by technology

The impurities cause scaling along the tube walls (known as “tube fouling”) which reduces heat transfer effectiveness and may eventually lead to plugging of the tube.

Over time, scaling adversely impacts steam production and fuel consumption with subsequent impact on unit operation and therefore oil production from the oil sands.

Most oil producers employing OTSG technology utilize multiple OTSG units mainly due to the scaling issue.

Further, when the OTSG unit is used for the oil sands, the production may be delayed for several days to even a month or more, while the production envelope restabilizes the heat and pressures underground.

However, the additional OTSG unit available for use when the other unit is offline is an intensive capital expenditure with operating expenditures as well.

Further, the turning off and on of the OTSG unit in the descaling process has a measurable impact on useful life on the tube or tubes and related equipment due to thermal stresses from transient conditions, thereby increasing maintenance with labor and material replacement costs over the life of the system.

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