How do you define the scope and objectives of a PFD for FEED?

1 Understand the project goals

Before you start drawing the PFD, you need to have a clear understanding of the project goals and requirements. What is the purpose of the project? What are the expected products and specifications? What are the key performance indicators (KPIs) and constraints? What are the environmental, safety, and regulatory standards? You can use the project charter, the statement of work, and the basis of design as references to define the scope and objectives of the PFD.

2 Identify the process units and streams

The next step is to identify the main process units and streams that are required to achieve the project goals. You can use a block flow diagram (BFD) or a process schematic as a starting point to outline the main process steps and the inputs and outputs of each unit. You can also use a mass balance or a heat balance to calculate the flow rates and compositions of the streams. You should also consider the utilities, such as water, steam, power, and fuel, that are needed to support the process.

3 Select the equipment and operating conditions

Once you have the process units and streams defined, you need to select the appropriate equipment and operating conditions for each unit. You can use process simulation software, engineering standards, and vendor data to help you with this task. You should consider the technical feasibility, the economic viability, and the environmental impact of your equipment selection. You should also specify the design pressure, temperature, level, and flow for each equipment and stream.

4 Add the process control and safety elements

The last step is to add the process control and safety elements to the PFD. You should include the instruments, valves, controllers, and indicators that are used to monitor and regulate the process variables. You should also include the safety devices, such as relief valves, rupture disks, flares, vents, and alarms, that are used to prevent or mitigate hazards. You should follow the relevant codes, standards, and best practices for process control and safety design.

By following these steps, you can define the scope and objectives of a PFD for FEED in a systematic and consistent way. A good PFD can help you to communicate the design concept, evaluate the alternatives, and prepare for the detailed engineering phase of your project.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?