Demonstration and Evaluation of Sludge Volume Reduction Technology

Crude oil contains heavy waxes and asphaltenes, which eventually accumulate at the bottom of crude oil tanks as sludge. Therefore, it is necessary to remove sludge periodically to restore the original storage capacity of crude oil tanks or for tank inspection and overhaul. Conventionally, crude oil washing (COW) has been used to remove sludge from tanks. However, sludge is disposed of as industrial waste, resulting in significant costs. To solve this problem, sludge volume reduction technology (SVR) was developed as a new technology. The key point of this technology is to recover reusable oil from sludge using a centrifuge and mix it with crude oil without re-sludging. From the results of the study, it was found that re-sludge generation can be suppressed by mixing the recovered oil with the original crude oil under turbulent flow conditions while heating the oil when mixing it with the crude oil. Furthermore, the demonstration test of this technology was conducted in the UAE, and it was confirmed that about 5200 kL of recovered oil could be obtained from about 9000 kL of sludge accumulated in a crude oil tank, and that the technology was effective in reducing sludge by more than 50 %.