Sulfur and acidic impurities in crude oils pose serious hot oil corrosion problems in crude distillation units (CDU) and associated vacuum distillation units (VDU), especially with the increase in processing of lowquality, opportunity crudes. In the range of 200-400˚C, reactive sulfur compounds cause sulfidation corrosion of ferritic carbon and chrome steels in CDU, VDU, and front ends of downstream units operating at hot oil temperatures. Over the same temperature range, naturally occurring carboxylic acids in crudes can be so aggressive that higher alloy, austenitic stainless steels containing >2.5% Mo are required for processing high acid oils.
Product Number:
MECC23-20054-SG
Author:
Sridhar Srinivasan, Gerrit Buchheim
Publication Date:
2023
$20.00
$20.00
$20.00
Margin improvement in crude processing can benefit from new knowledge-based, engineering solutions, designed to offer a framework to harness the immense power of plant and process data to achieve superior process efficiencies, productivity and reliability. The need to work with opportunity crudes in refinery unit operations, a business imperative of crude blending and crude slate optimization, has meant that operators face substantial risk of corrosion damage in the crude distillation unit (CDU), vacuum distillation unit (VDU), associated equipment and side stream piping. Using Total Acid Number (TAN) and Sulfur content in crudes as proxies for Naphthenic Acid and Sulfidic corrosion in refinery operations has often led to conservative, cost-inefficient decision making in terms of crude selection, crude processing, and unit metallurgy specifications. Alongside, the refining industry has consistently sought, for reasons of improved economics and ROI, to move in the direction of processing heavier, high Sulfur, high acid opportunity crudes. Such a directional shift has been a consequence of depleting reserves and declining sweet crudes. Processing of low-cost opportunity crudes as an integral part of crude-slate planning has become a business necessity to improve refining margin.
The CorrExpert®-Crude application enables realization of the business need to work with opportunity crudes without risking corrosion damage to CDU / VDU equipment. Leveraging crude assay data and information available through cloud-based process historian, the framework can also facilitate enforcement of appropriate Integrity Operating Windows (IOW) through utilization of corrosion rate as a dynamic IOW parameter alongside other key operating variables such as TAN, Sulfur, Fluid Turbulence and Temperature. The system’s ability to seamlessly collaborate with other platforms including crude blending and supply chain planning applications such as Haverly®1 and PIMS®2 has important implications for creation of a digitalized solution integrating crude assay with automated predictive analytics en route to achieving crude processing flexibility, improved reliability, and enhanced profitability.
