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Summary Karl Fischer Experience from LOOP – Harold Osborn of LOOP talked to the group about their experiences with Karl Fischer measurement. When LOOP was first opened in 1981, centrifuge was used for S & W determination. Due to the use of underground storage for the crude and the inaccuracies in the centrifuge method, losses of a higher proportion than normal were experienced through the storage. LOOP switched to water by distillation in early 1983 for custody transfer and sediment by extraction. In 1985, Karl Fischer testing began and over 4,000 samples were tested on 49 different types of crude. In 1989, LOOP started using Karl Fischer for custody transfer. Currently, Karl Fisher is run on two separate samples for each batch and the results must be within an allowable difference. The "allowable differences" were developed internally from the API standards. If the test results fall outside these parameters, two new samples are taken and retested. LOOP uses Karl Fischer on all connecting carriers transfers for custody transfer and shipper balances. However, if the connecting pipeline does not accept the Karl Fischer, they do perform both tests so that the carrier can use centrifuge results for their customer. After several thousand samples, LOOP has calculated a 0.08% difference between KF and centrifuge on Seg 20 crude, which is defined as a relatively light, sweet crude. On Maya crude, which is very heavy and sour, the difference can be up to 0.25%. For Mars crude, the delta is about 0.06%. In all cases, Karl Fisher measurements were higher. Solvent Disposal for Karl Fischer – The solvent used in Karl Fisher measurement is hazardous and must be properly disposed of. Kim Mohajer of KAM Controls indicated that an individual company’s internal safety department is the best source for a waste management program. He did note that the reagent is good for 25 to 100 samples before changing is required and is used in very small amounts (100 ml) for each piece of equipment. Capturing the used solvent in a can, for example, and collecting it until a reasonable amount has been generated is not usually costly or time consuming. Other - Patti Edens of Equilon Pipeline and Clifford
Mills of Conoco both reported that their respective companies are still
gathering data and have nothing new to share with us. Doug Arrick of TEPPCO is on the ASTM / API water measurement committee. He reported that they are looking into recalculating precision and bias for some of the water tests. The currently published results were generated from different samples and there are some discrepancies that need to be corrected. Doug is looking for ten labs to participate in this new study. Anyone interested can contact Doug at darrick@TEPPCO.com or (713) 450-4385. There is no cost to the labs to be a part of this study. The Facilitator will provide Doug with a listing of the last COQA Round Robin participants and Clifford Mills suggested contacting Anne McClendon at ASTM to possibly obtain the listing of the Interlaboratory Crosscheck program (ILCP) participants. Doug also noted that ASTM is revising their sampling standards and protocols. Comments can be addressed to Doug. Harry Giles | |