Maximize Use of Your Existing Flare Structures

Due to the design vintage of many petroleum refineries and petrochemical plants, existing pressure relief and flare systems may be overloaded because of:

• Prior unit expansions / upgrades have increased the load on the flare for combined flaring scenarios beyond the original design intentions
• The desire to connect atmospheric relief valves to the flare for environmental and safety consideration and to eliminate blow down drums
• The addition of new process units that need access to flaring capacity

As a result, many petroleum companies are engaged in comprehensive flare systems evaluation and upgrading projects to ensure continuing safe operations, to MAXIMIZE the use of their existing flare systems, and to MINIMIZE the need for modifying existing flare structures or building new ones. Achieving these goals presents several engineering challenges:

1. Which existing atmospheric relief devices present vapor cloud explosion and thermal radiation hazards and need to go to the flare?
2. What is the impact of the additional flaring loads on the existing flare header system and individual relief devices during combined flaring events (such as loss of power or cooling)?
3. Where and how many High Integrity Protection Systems (HIPS) should be employed to reduce the worst case flaring load?
4. How should the HIPS components be configured to achieve the required safety integrity level (SIL)?