Apr-2012

Process unit cold eyes review

Operators of process equipment have an obligation to understand the existing and future potential for unit reliability and operability.

Scott Sayles, KBC Advanced Technologies

Article Summary

Day-to-day operations keep the operator attuned to the current operating conditions, but may potentially not account for longer-term threats or those beyond the operator’s experience. Having an outside person review the process unit operations allows for a new perspective and the identification of potential issues, which, if not addressed, can have adverse consequences.

This article discusses the process unit Cold Eyes Review (CER) and the methodology involved in identifying, evaluating and mitigating the identified operational issues. Case studies are provided to demonstrate the usefulness of external review.

Overall CER methodology
The overall CER methodology is an encompassing concept that starts with the unit review and ends with implementation of the results in the field. The goal is to enhance process integrity to meet the goals of safety, environmental compliance and stakeholders’ return on investment. The process has three phases: investigation, evaluation and implementation. Each phase is discussed independently. The overall interconnectivity of the process is shown in Figure 1.

Identification phase
During the identification phase, the unit’s design, configuration and operation are reviewed for operability, maintainability and performance. This takes the form of understanding the process operations and the issues around mechanical performance, procedures related to changed operations, and human interactions. The operations, reliability and human performance are then the three keys to understanding the improvement opportunity. The result is identification and prioritisation of a list of mitigation opportunities that enable the unit to meet the identified refinery goals and objectives.

Evaluation phase
In the evaluation phase, the identified opportunities are then studied further using individual or combined tools:
• Petro-SIM is used to investigate the process operations and suitability of the process design to meet the goals and objectives
• Reliability, availability and maintenance (RAM) methodologies and concepts rapidly identify how rotating and fixed equipment design, maintenance or operation affects unit reliability and their impact on goals and objectives
• Human performance improvement (HPI) techniques to improve training, procedures and work practices are used to ensure changes made in the field are captured for future operations.

These tools and the KBC consultant’s expertise to interpret results set the basis for determining the root cause of the identified issues. Process impacts, such as changes in oil compatibility that affects fouling, loss of exchanger heat transfer, catalyst deactivation and other process-related effects, can be quantified using Petro-SIM supported by a refinery provided price set. Petro-SIM is KBC’s state-of-the-art flowsheeting tool, which enables embedding of rigorous kinetics models to facilitate kinetics-level simulation of an entire unit.

At the conclusion of the evaluation phase, the opportunities list developed is further broken into packages we call process technology packages (PTP). These packages are detailed descriptions of the process, mechanical and procedure changes that must be implemented to reach the desired refinery goals and objectives. The PTP may contain process, mechanical and procedural/cultural changes.

Implementation phase
The implementation phase of the CER is the final piece of the study. In this phase, the identified solutions are taken to the field and KBC explains, trains and guides the operator to support the successful realisation of the project potential.

Process operations
We view process operations as the chemistry, kinetics, thermodynamics and stoichiometry of the refinery plant. Understanding how these interact and work together within the refinery allows appreciation of the potential to reduce expenses but better utilisation of the refinery feedstocks. Purchasing new crudes or intermediate feedstocks requires careful consideration of the downstream impacts to reliability and operational changes needed.

Reliability
Mechanical equipment is the backbone of the refinery’s performance. The ability of the equipment to perform within the context of defined process operating conditions can allow success or failure of an individual piece of equipment. Understanding the interaction between process operations, mechanical capability and human performance gives the refinery a basis to maintain plant availability and reduce expenses.

Human performance
Human interaction with the equipment can have a profound effect on process operations and equipment reliability. Mis-operation of equipment outside the intended boundaries is one of the leading causes of equipment failure. Prevention and mitigation occurs by proper procedures, training and supervision.

Independent assessment, CER
The CER methodology applies the concepts discussed above using a fresh look at the refinery. Often, refinery personnel are taxed with many daily tasks that prohibit them from finding the time needed to improve or change the fundamental issues they face. In some cases, they have the base knowledge but not the time to develop the solutions, while in other cases the fundamental cause remains unknown but workaround solutions are found to allow operation to continue. This leads to a culture of acceptance that things cannot change.