Where to Start?
Evaluating your current flare design documentation needs, the first question to answer is "what do you have?" Without a trusted baseline study that outlines the design basis for the current operating conditions, it is next to impossible to accurately implement any project changes. So the best place to start is to understand what you have.
The baseline study can supply you with a "snapshot" of what the flare loads look like, but more importantly, it can identify sections of the flare that need to be unloaded due to excessive flow or sections that may have some extra capacity. This gives you a conceptual idea of where to tie-in new units; or, if the flare is overloaded, where removing loads would be more beneficial. The revised flare baseline works both ways – it considers all the loads that have been added since the flare was baselined, but it also removes loads from units that may have been taken out of service or mothballed. Without the flare baseline, you are operating in the dark.
The "Flare Engineer"
Who is minding the flare? This is quite possibly the most important question that is rarely asked until there is a problem. Is it the Project Manager for the project implementing the changes to the facility? Could it be the Utilities Engineer responsible for all the utility systems in the facility? Is it the EPC or Engineering Department performing the engineering for the project? The real answer is "none of these."
The proper way for a flare to be managed and updated is to establish a dedicated resource whose principal responsibility is managing the flare. This leads to a philosophical question: Is the flare system treated as a unique utility system at your facility? If the answer is "yes", then you are ahead of the game. If not, this article should be setting off alarms. The flare is a utility system with defined limitations. From this point forward, we can assume that the flare is treated as the unique utility system and we will refer to the individual(s) responsible for such systems as the "flare engineer". This Flare Engineer should not only be familiar with the operations of the facility but also familiar with the relief system / flare methodology and design criteria.
Having a dedicated Flare Engineer, that is only responsible for the flare and its operation allows for consistency across multiple projects and changes. This Flare Engineer is a critical resource for the facility and Project Managers when evaluating the project changes.
An Illustrative Example:
A refinery has recently completed a flare baseline study in anticipation of four projects that are currently in various stages of "engineering completeness." However, they do not have a Flare Engineer to coordinator all the projects and determine each project's impact to the flare system. Without the Flare Engineer, four different engineering firms "working in a vacuum" proceed without knowledge of the other limitations and results in significant impacts to each of the projects' budget and schedule.
Most facilities simply do not have the luxury of extra, available engineers; let alone engineers with this particular knowledge base. However, the Flare Engineer does not have to be a singular person. This job might be better staffed with a team of engineers from a Pressure Safety Consulting organization. They have the technology and expertise to perform this function effectively and can devote the right amount of resources depending upon project load.
How to Incorporate into the Project?
The baseline study is now complete and the Flare Engineering role has been defined. We now know if and where there are issues with flow, velocity, pressure drop, and other potential concerns. So how can the Flare Engineer use this tool to incorporate its use into any given project? The answer is by proactively incorporating their role into each project team - with the sole responsibility of flare management.
Where in the project's lifecycle should this work be completed? It is imperative that the flare analysis is evaluated throughout the project lifecycle, in order to minimize the impact to the project budget and schedule. Here is a description of the work to be completed in each engineering planning phase:
Conceptual Phase: During the conceptual phase of the project the flare should be evaluated to identify the major changes the project will make to the process / facility and compare those changes to the baseline study. The goal of this phase is to determine if there will be a major change to the flare system. If the answer is yes or maybe, then funding should be allotted to study these effects in subsequent phases and make the appropriate changes to the flare system.
Feasibility Phase: During this phase, options are considered and identified based on project drivers (economics, environmental, major maintenance). Each option must look at the impact on all the utility systems including the flare system. The impact of changing the flare must be included in the cost of each option.
FEED Phase: With the project option and path forward identified, so too can the flare evaluation begin in earnest. The effect of the project on the flare is now defined and can be determined if major changes are required to the flare, or if there is excess capacity in the flare system. If changes are required, alternatives to those changes can also be explored during this phase. For example, if a project is installing a new unit and the flare system cannot handle the additional load, there are several ways to solve the issue:
- Replace the flare with a larger system / more capacity or modify the existing flare section where bottlenecks have been identified.
- Use safety instrumented systems to reduce the flare loads in the new or existing parts of the facility.
- Or, perform a Flare mitigation analysis technique like a QRA.
However, these options must be "scope complete" prior to proceeding to the detailed engineering phase of the project in order to minimize scope creep and impacts to project budget.
The next step in the process would be to incorporate all the changes into the flare documentation with "as-built" piping and relief valve information. This ongoing, cyclical process keeps the flare design basis and required documentation evergreen, ensuring you always have the most current information at your fingertips.
The flare system and its capacity are often overlooked or neglected through the numerous ongoing changes that occur at a facility. No matter the motivating driver for specific projects, the flare is almost always impacted one way or the other.
Bringing the flare system to the forefront and categorizing the flare as a utility system with the dedicated resource(s) is an essential step in good flare management practice. Having a flare baseline is the most critical step in this process, as it is the tool that all future planned changes and projects will use to determine their specific impact to the flare. The impact to the flare must also be considered and quantified at each stage of the project planning lifecycle. By following these three steps, facilities can install an evergreen flare process basis, reduce project scope and budget risk, and obtain PSM compliant documentation.