Optimizing Dehydrators Operation Using Dynamic Adsorption Time

Abstract Molecular sieve is a solid desiccant widely used in gas plants for dehydrating wet process gases. Compared to other desiccants, molecular sieve can reduce water content in the outlet gas to less than 0.1 ppmv. This is a must requirement for conditioning feed gas to cryogenic applications. On the other hand, Molecular Sieve is generally more expensive and energy exhaustive. This paper describes the successful implementation of the Dynamic Adsorption Time Control Module for dehydrators in natural gas liquid (NGL) recovery trains at Saudi Aramco's Hawiyah NGL Recovery Plant (HNGLP). The module optimally utilizes the available dehydrators capacity by applying dynamic adsorption time for dehydrators based on available desiccant capacity, processed gas flow and incoming water content. As a result of this optimized utilization, the frequency of regeneration cycles is reduced. This results in extended desiccant lifetime, and reduced lost revenue and energy consumption over the desiccant life cycle.