We’ve all heard the adage: “water and oil don’t mix.” But in the energy measurement world, that’s not strictly true. The reality is that water does sometimes mix with oil, or other petroleum products, and this can cause major issues both operationally and financially.
Water in petroleum processing is a very big concern. Water in pipelines can settle and cause corrosion. Water can combine with other harmful chemicals such as SO2 or H2S making disposal of this water corrosive, noxious, or even potentially fatal. Water in a refined product such as gasoline can render an entire batch unmarketable. And water in any petroleum product, if not quantified, can cause financial losses from paying product market value for water.
When it comes to water, there are a few strong tools in our toolbox to quantify the problem. These tools are the two common test methods of centrifuge tests and coulometric Karl Fischer (KF) titration tests.
- A centrifuge test works by physical separation using centrifugal force to spin the heavier water to the bottom of a petroleum sample that is typically lighter in density. Centrifuge tests require the use of a solvent (common solvents are Stoddard, kerosene, toluene, xylene, etc.) to “thin” the petroleum product and aid in separation.
- Coulometric Karl Fischer titration tests work by chemical reaction where water is consumed in the reaction. This reaction passes a charge through the coulometric cell where the charge is proportional to the amount of water consumed. Since KF titration is a chemical reaction, no solvent or separation is necessary.
Either of these methods can be conducted in the field or in the lab. However, KF titration in the field has challenges due to its sensitivity to things such as changing temperatures and humidities.
What both methods have in common is that they require a strong sampling and training procedure to obtain accurate results. The workhorse on the field services side is the centrifuge test. Unfortunately, few field technicians appreciate the attention to detail that is required by this method. A lack of attention to detail on the choice of solvent to use, the pretreatment of that solvent, the choice of demulsifier, or even the reading of the tube incrementation properly can easily change the resulting percentage of water by +/-0.2%.
At SPL, our field technicians are trained to be acutely aware of the ramifications of not sampling correctly or processing a sample incorrectly. Each field technician is trained extensively in sampling methods and on the gold standard API Manuals of Petroleum Measurement Standards (MPMS) Chapter 10.4 on determination of water in crude oil by in-field centrifuge method. Similarly, on the lab side, SPL lab technicians are trained to utilize best in class equipment to produce quality results through the ASTM D-4928 method of KF titration.
Additionally, SPL’s data management team has developed robust tools to ensure that every procedural step of API MPMS Ch. 10.4 is followed, and every piece of information is collected, validated, and auditable. The ultimate goal, which we are working tirelessly on, is to bring this functionality and visibility to our customers through our best in class SureVue software.
If you are experiencing water imbalances in your system or just need to track water to its source, SPL can provide the services, knowledge-base, and data to support your operations. Whether it is a HSE concern, an operational integrity concern, or a financial concern, reach out to info@spllabs.com to see how we can help support your business.
Chuck Woods | Vice President, Special Projects Chuck Woods holds both a BS (2002) and MS (2004) in Chemical Engineering from Mississippi State University. He began his career at the University of Delaware, dedicating a decade to graduate research. In 2013, Chuck joined Volumetrics as a Senior Engineer and now serves as VP of Technology, leading internal and customer training programs. As an SME in proving operations, Chuck chairs API’s Committee on Petroleum Measurement and regularly contributes to ASGMT and Rocky Mountain Measurement Society conferences. Outside work, he enjoys outdoor activities with his family and volunteers as a youth sports coach. |
