Efecto de temperatura y humedad en refinerias

Rental strategies counter seasonal performance problems
Engineered solutions can reverse the adverse effects of high temperatures and humidity
UmEsh mathUr Aggreko Process Services

P

etrochemical and refinery processes rely on efficient heat transfer to maximise efficiencies and ensure safe operations. While most plant operators manage a utilities system sufficient to supply a small city,many are not aware of proven rental strategies to better manage risks, limit losses and seize unexpected market opportunities. In particular, ambient air temperature and humidity rise significantly during the peak summer months, relative to winter conditions, which adversely affect major heat exchange equipment throughout the plant. Often quite significant deterioration in performance forcesplant operators to make some unpleasant choices, chief among which is a reduction in unit throughput. Owing to the integrated nature of major refinery and petrochemical processes, such problems at any unit usually force both upstream and downstream units to also cut production. Market demands often peak during the summer. For example, gasoline sales are highest

when ambient conditions forceproduction bottlenecks throughout the refinery. These scarcities drive refining margins up significantly, thereby creating huge economic incentives to restore unit capacities. The magnitude of monthly

monthly economic losses caused by production cutback can easily equate to millions of dollars
economic losses caused by production cutback can easily equate to millions of dollars.

temporary seasonalstrategies

This article examines seasonal cooling problems and issues that commonly occur every year, and how owners have justified acquiring engineered solutions to solve emergencies and production shortfalls in such instances. Additionally, the

benefits of employing rented equipment, best practices and results that have been achieved are presented in several examples. The chief merit ofthe rental model for solving seasonal cooling problems is that solutions can be deployed at short notice, often within a month or less. The main requirements are: • Engineering services to develop all feasible alternatives and the benefit-to-cost ratio in each case • Ready availability of process equipment that has been fabricated and maintained in a manner fully consistent with industry bestpractices • Transportation and field assembly, with full cognisance of applicable safety and environmental standards • Full documentation of process and equipment design details; emergency, startup and shutdown procedures; operator training materials; and all pertinent details to help ensure conformance with management of change and process safety review criteria. In the past, many operatorswww.eptq.com

PTQ Q1 2011 1

have not expected that seasonal or temporary projects relying on rental equipment could successfully meet such requirements. This is simply because most players in the equipment rental industry either have not emphasised such aspects or face difficulties in adhering to stringent industry requirements, thereby precluding their participation in the development ofsystematic, sound solutions. It is useful to think of temporary solutions for problems in three categories: • Emergencies These are situations where the failure of crucial equipment must be rectified immediately. Replacement by a suitable equivalent is the best alternative in such cases • Planned outages Here, major parts of a unit (or the entire process unit) are scheduled to be taken out of service forroutine maintenance. The degree of the challenge faced is directly related to the impact such outages have on the rest of the facility. One solution can be to cool and divert the unit feed to temporary storage while the unit is out of service, thus allowing upstream units to stay online. Otherwise, it is imperative to take all possible measures to minimise the duration of the outage by expediting...