For refiners challenged with increasing regulations, blending operations are a major area where automation investments can help meet these regulations and improve operational performance.Emerson’s Marcelo Carugo, who leads the refining and petrochemical industry team, shared the details of a feasibility study they conducted for a North American refiner to identify opportunities to improve the gasoline and diesel blending systems.
The consultants who worked with the refinery staff investigated component/finished product tankage adequacy, the existing blend models and how they could be optimized, the product quantity and quality certification procedures and the impacts of recent expansions and feedstock changes.
The intent was to use as much of the existing instrumentation, analyzers and control, unless justified otherwise. The evaluation included benefit estimates based on expected grades, quantities, specification and costs over a multi-year time span. This evaluation also included a migration plan and recommended control strategies to achieve the projected benefits in a planned, stepwise fashion.
One key area to optimize operations was to look at the data flows in the blend system interfaces. Data interchange requirements were developed for systems including blend scheduling, laboratory information management system (LIMS), production accounting and blend reporting, such as blend batch reports.
The importance of data flows also extended to the instrumentation for blend control functions, tank level monitoring, motor-operated valves, and other important pressure and flow measurements.
The analysis led to a conceptual design to achieve the identified benefits. Recommendations included changes to infrastructure, business processes and staff organization. For example, inaccuracies in flow measurements were due to infrequent preventive maintenance and calibration, and incorrect volume compensation. Recommendations included flow measurements rated for this high turndown blending application that provide online diagnostics, meter verification, and better handle the turndown and compensated volumetric flow requirements.
On blend ratio control, the Emerson consulting team recommended that improved blend quality control could be achieved through simple improvements in regulatory control and measurement devices. Reduction in variability enable reductions in Reid Vapor Pressure (RVP), octane giveaways, reblending and touchups.
On blend optimization, the team noted that meter accuracy and tighter blend control will minimize variations around the optimum blend ratio and that measurement errors drive the recipe away from optimum.
Combined measurement errors can be multiplicative and not easily compensated with simple quality bias adjustments. The accuracy of flow (and quality) measurement of blend components for blend optimizers helps to maximize the benefit (profitability).
The blend optimization function should also operate more than 95% of the time to achieve the expected benefits.
Marcelo noted that recommendations were also provided around blend scheduling, blend batch reporting and key performance indicator (KPI) monitoring.
If you’re looking for ways to review your blending operations in terms of potential benefits and returns, technology, work processes and project execution plan, contact the refining industry team.
You can also connect and interact with other refining experts in the Refining group in the Emerson Exchange 365 community.