DESIGN/BUILD OF A NGL FACILITY COMPLIANT WITH LDAR DTM—METHODS FOR REDUCING INITIAL AND LONG-TERM COSTS TO OWNER

摘要

This paper discusses a case study in designing and building a green-field, grassroots NGLFacility in a non-attainment area (Houston) that complies with the EPA’s LDAR (Leak Detectionand Repair) and LDAR DTM (Difficult to Monitor) regulations: 40 CFR Part 60 Subpart VVaand TCEQ regulation 5. LDAR DTM regulations require that no more than 3% of the LDARregulated valves in a facility be a classified as ‘difficult to monitor.’ Typical front-end loadingand preliminary design activities do not sufficiently address the design and cost implications ofcomplying with the aforementioned regulations. Through face-to-face meetings between theowner and owner’s engineer, the following parts of a “design with LDAR in mind” basis wereestablished:1. What facility services fall under the LDAR regulation? What is the site’s %VOClimit?2. What qualifies a valve as “difficult to monitor”?3. Which valves are necessary for operations and maintenance and which valves are forconstruction only?Planning and designing for difficult to monitor valves early in a project’s life cycle – beforebeginning of detail design – can greatly reduce the compliance costs of monitoring for an NGLfacility and reduce total installed cost of the project as a whole. Among the ways we found toreduce the operating cost are: 1) locate instrumentation accessible from grade, 2) designplatforms to encompass vessel trim, 3) minimize number of valves and flanges inside the piperacks, and 4) remove non-essential valves either during design or before commissioning(hydrotest vents). Incorporating these items and others into the design results in a facility whereLDAR and LDAR DTM valve counts are lower, monitoring cost is reduced, and compliance isachieved before scheduled startup.