Optimization of Plant Stoppages

Luis Amendola, PhD. 
Industrial Engineering Management

 Gerente de Mantenimiento Metanol de Oriente, S.A, Pequiven S.A 
/ Mitsubishi Corporation / Mitsubishi Gas Chemical ( Japón) 
Complejo Petroquímico de Oriente  José - Anzoategui - 
Venezuela. Profesor de Postgrado en Ingeniería y Gestión . 
Director de Postgrado de Ingeniería de Mantenimiento y 
Confiabilidad UGMA- Barcelona-Anzoategui- Venezuela
e-mail: lamendola@metanoldeoriente.com / piquita@telcel.net.ve

Through the coordination of major maintenance scheduled stoppages at petrochemical and refinery plants and the exchange of information and comments of people from all levels in the organization, I decided to compile the contents of this article. I wish it will be useful for all participants in this kind of projects. It may be of use not only to those in refineries or petrochemical plants, but for manufacturing facilities as well.

Recent studies from international organizations show a huge gap between the cost of these stoppages  in Latin America and the same at world level. A great deal of these differences can be identified as maintenance execution costs and duration of stoppages. These are variable depending on:

• Importance and complexity of work to be performed

• Application of best practices and reliability methodologies

When we plan and schedule these major maintenance projects we must make some considerations of additional factors such as:

• Operational reliability

• Maintainability

• Availability

That is we should have the answers to questions like: 

• What activities will have to take place during stoppage and how can we optimize time and cost of the execution?

• What activities are not required?

• What activities can be done routinely and at which point in the process of the plant?

• What activities can be performed during the next stoppage?

To this regard I suggest we analyze the following methodology:

Work Methodology

Conform a "natural" work team comprised of people from:

Maintenance, Operations, Materials, Industrial Safety, Process Engineering, Human Resources, Services and Finance Departments.

This has the purpose of evaluating the achievement expected from the maintenance jobs to be performed during the stoppage as well as to identify optimization opportunities.- Just as all these improvement activities, this one has to receive strong support from top management in the company. We will be able to listen to each participant and learn in advance what can or cant be expected.

In the above diagram are the steps I propose for the Natural Work Team.

Application of Reliability Techniques.

The application of operational reliability techniques in the maintenance management at industrial facilities optimizes the achievements of maintenance representing substantial savings. Among others, the advantages of these techniques will:

• Eliminate or diminish subjectivity and uncertainty usually attached to most decisions that must be made. This will prevent overestimations that are common place in such projects. 

• Root causes and occurrence probabilities of each problem will be analyzed in advance and the operational consequences as well as safety issues.

In other words, there is a clear awareness of the risks of each decision and this allows the team to think about improving the maintenance operation reducing therefore undesirable consequences.

Let us see some of those reliability techniques being utilized by large corporations with excellent results: 

Cost - Risk Optimization (CRO)

Continual limitations in cash flow in refineries and petrochemical plants make it mandatory to justify whatever expense and labor to be utilized in a planned plant stoppage. That means we must make sure there will be investment returns (savings or extra revenue),  very clearly associated to the project. The losses related to opportunities and production missed during the stoppage should also be considered. In other words: The profit derived of the project has to be clearly seen.

These are the questions that should find an answer:

• Is there a profit if we go ahead with this project?

• Is the investment (parts, materials, labor), justified by the profit?

• What will the return rate be?

Risk Based Investment (RBI)

This methodology provides the basic tools and administers risk as the measure to define the inspection programming, so that each piece of equipment is catalogued and hierarchically scheduled according to the risk its failure may represent. Once the risk associated to each piece of equipment is clearly determined, this can be diminished and/or controlled through different methods such as: optimization of type and frequency of inspection.

“Reliability, Availability y Maintenability” (RAM). 

The RAM technique was developed by Sun Oil in order to optimize their plant stoppages. It is about deciding if given the reliability, availability and maintainability of the equipment, it should be scheduled to be maintyained during a certain stoppage or not. They compare the evaluation to the option of "doing nothing". Whatever decision is more cost effective, it will be made.

“Asset Performance Tools” (APT inspection).

Another methodology also applied in search for opportunities to improve or optimize plant stoppages has traditionally been the APT Inspection. Again, the idea is to evaluate or determine if the task should take place during the stoppage. If it is timely according to the machine's appropriate interval between inspections and considering cost-benefit-risk of alternative inspection strategies. Also a balance has to be made about the reliability, performance, unavailability and impact of that piece of equipment.

This analysis is one of the most powerful tools currently available to generate the criteria that will back any decisions on inspection of lines and static machines or devices. 

• The scope must be taken as the objective of each step in the development of the stoppage, since the opportunities to improve or change the process will vary each time.

• To determine the reach of the project, the analysis procedures and reliability techniques will be combined to evaluate the convenience of performing the maintenance task.

• The effective and opportune participation of the team as a whole is key to reach the goal of optimal accomplishment.

 Recommendations 

This is a methodology based on the application of the best practices and reliability techniques. It will allow the plant to have considerable savings and establish a structured planning process to achieve optimal results out of scheduled stoppages. On the other hand, there will also be some other benefits as the extension, intensity and number of tasks to be performed will translate into a higher availability of the plant.

References and Bibliography