Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
(OP)
In northern Canada SAGD (Steam Assisted Gravity Drainage) operations are becoming very popular to produce heavy oil out of tar sands. This process requires injection of steam at very high temperatures into the producing formation. The company that I work for is experiencing erosion in fittings and valves at wellheads. Common material used is carbon steel 1018. Could anybody tell me if there is any type of model or software that could calculate metal loss due to erosion from high velocity steam?





RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
We have used field thickness data to calculate erosion rates for boiler tubing to predict tube weld repair or replacement. There is no substitute for real-time erosion data that can be converted to a rate in mils per year (change in thickness/time interval).
As a side note, have you considered upgrading material to a 5% Cr- 1%Mo alloy steel? We have used 5% Cr- 1% Mo fittings and valve bodies on HP feed water heater drains to increase erosion resistance from steam flashing. Once you calculate erosion rates for your fittings and valve bodies, you can decide if you need to upgrade material.
RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
When there is two phase flow, then higher Cr is needed to help 'strengthen' the passive film. This is where the 2% Cr alloys would be a good option. These are the traditional high performance boiler tube materials and they work well.
Most of the research on this subject has been in hte nuclear power industry. Much of the work was done at Chalk River.
On the production side, much of the tubular for these systems is being converted to 41003, a modified 12% Cr that has a mixed ferritic/matensitic structure. This is needed because of the additional corroison and erosion issues in the produced fluids.
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Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
The most commmon corrosice activity is caused by having an alternating range of pH and O2 content. If one opearates with zero O2 and high pH, then magnetite forms. Magnetite is a weak scale whcih can be easily removed by erosion, and once the oxide scale is lost, then the erosive action of the high velocity fluid is amplified.
This corrosive action is furhter amplified if there then occurs periods of high O2 and /or low pH. The occurance of these upsets will remove the magnetite .
The best corrosive protection was found by use of the "combined oxygenated treatment " method- so long as gthe fluid is always moving and is not stagnant, excess O2 and medium pH ( 6.5 < pH <8.5) will cause a hematite scale to form , which is very strong and corrosion resistant.
Raising the Cr content to 1% will generally cause the erosive-corrsion life to be extended by a factor of about 7. However, the piping will then need to be PWHT after welding.
RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam
Check your piping for proper velocities, and insulation integrity, as well as the metallurgical recommendations made above, all of which were excellent.
rmw
RE: Erosion Rate Calculations of Carbon Steel Due to High Velocity Steam