A major concern among oil producers today is maintaining their crude oil Reid vapor pressure (RVP) at transportable safe levels. 10 psia RVP or less is a common threshold that midstream and tankers set to protect their equipment and personnel. There are two major safety issues related to high RVP. The first is vapor pressure, which increases with temperature. The second is pumping cavitation, which occurs when the TVP (True Vapor Pressure) or bubble point vapor pressure reaches a V/L ratio around 0/1. This is caused by the acceleration of the crude oil, which leads to areas of low pressure. Once the pressure of the surrounding area (area around the crude oil) becomes lower than that of the crude oil, bubbles form, grow, and then bust. The bubble burst near the surface of the pipe or pump and this action releases a shockwave that may cause damage.
Reid vapor pressure is a common measure of a substance’s vapor pressure at 100oF (37.8oC). In other words, it is the liquid’s ability to volatilize. The RVP of crude oil increases with the increasing presence of flammable gases and other volatile flammable liquid components (e.g., hexanes).
OTA’s VRT-Max is a great solution to lowering RVP. The vessel is designed to MAXimize flash and simulate working and breathing losses that would otherwise occur at the storage vessel facility, possibly resulting in an affected facility status. The oil has time to stabilize at a minimum retention time of 30 minutes, ensuring that maximum vapor breakout occurs.
(Internal configuration is proprietary)
Degree of hazard.
The HMR vary the stringency of requirements according to the degree of risk various substances pose in transportation. Many hazards, including the flammability hazard of liquids, are subdivided into three risk levels:
Packing Group I – encompasses substances regarded as posing a high hazard level;
Packing Group II – encompasses substances regarded as posing a medium hazard level; and
Packing Group III – encompasses substances regarded as posing a low hazard level.
Flammable gases and vapors will ignite when they are mixed with air in certain concentration ranges. The lowest temperature at which flammable liquids produce vapor in sufficient amounts to support combustion is termed the liquid’s flashpoint. Under DOT and international regulations, a flammable liquid is a liquid that has a flashpoint of less than or equal to 140oF (60oC). Flammable liquids with a flashpoint of 73oF (23oC) or less are assigned to either Packing Group I or II. In essence, the flashpoint limits of 73oF (23oC) and 140oF (60oC) for flammable liquids indicate whether a substance has the potential of producing a flammable vapor under moderate ambient temperature conditions (i.e. 73oF (23oC)) or under the most extreme ambient temperature conditions (i.e. 140oF (60oC).
So let OTA’s VRT-Max take care of your crude oil’s high RVP and help make transportation mediums a safer place. Call your local sales representative with any questions!