Benefits of Using Deliquescing Desiccants for Gas Dehydration

Abstract Deliquescing desiccants have been used for gas dehydration for over 40 years. Historically this technology had limited applications due to poor desiccant quality and integrity, equipment design problems, operational difficulty, and limited drying ability. Recent advances in dry material blending and tableting, formulation, and equipment design have greatly expanded the application range of deliquescing desiccants. Deliquescing desiccants are now used to dry sales gas, fuel gas, sour gas, excess or "peak" gas, and for hydrate control. Operating and capital costs compare favorably to traditional TEG systems. Field data verifies the drying ability and performance of deliquescing desiccant systems. Because of the operational simplicity and closed system design, deliquescing desiccants offer many advantages over traditional drying methods such as triethylene glycol, including: no VOC or BTEX emissions, no ground contamination, no fire hazard, low capital expense, low maintenance, no "turn down" concerns, and simple operation. Used for hydrate control in gathering systems, desiccants offer a simple and inexpensive method to dry below pipeline dewpoint thereby allowing trouble free gas flow from wellhead to processing plant. At the plant, gas is further dehydrated to meet pipeline requirements. Desiccants have substantial advantages for drying sour gas both for hydrate control and pipeline sales. There are no emissions, odors, or glycol contamination, and vessels can be over-sized to extend the service interval to only several times per year, greatly reducing employee exposure to hydrogen sulfide. Because of it's simplicity and small footprint, desiccant drying of fuel gas yields increased revenues by using suction gas, not sales gas, for compressor fuel. The entire compressor throughput capacity can be sold, instead of a portion being used for fuel. Desiccant dehydration is well suited for remote, unmanned locations, which are not visited daily. Because operation is simple and service intervals long, operators can schedule maintenance and service weekly or even monthly. This reduces total operating costs and labor requirements.