(100e) Flare Loading Mitigation Techniques

Industry wide, flare capacities are reaching their limits. Flare system modifications are very expensive; ensuring the modifications are necessary is worth the effort. The use of short-cut methods (e.g. the normal vapor rate from the tower) can result in grossly overestimated design loads which can result in large amounts of capital to resolve either by the engineering re-calculation of the design basis or through facility modifications. For any relief scenario that can be construed as or used as a global scenario (or cases where simplifying or conservative assumptions may result in the modification of the facility or process), the following items are closely examined: loss of/reduced flow, mass balance limitations, heat exchanger limitations, and energy limitations. The use of this information in analyzing a flare system can significantly reduce the predicted flare load, by as much as 50% depending on the original design basis and number of modifications to the facility. These analysis tools can lead to the difference between moving forward with a capital project and scrapping the idea due to the increased cost of upgrading the flare system.