PSB Industries, a specialist in the design, engineering and fabrication of systems for dehydrating and purifying gases and liquids, highlights its skid-mounted LNG dehydration and/ or heavy hydrocarbon removal systems, which use molecular-sieve based temperature swing adsorption (TSA) technology to help LNG operators meet ultra-dry gas requirements and/ or address heavy-hydrocarbon contaminants before liquefaction.
PSB’s molecular-sieve LNG dehydration systems use TSA technology to remove water from natural gas before liquefaction. This helps operators meet stringent outlet-water requirements while addressing ice and hydrate formation, freeze-ups affecting valves, instrumentation and process equipment, and the risk of damage to cryogenic heat exchangers and cold boxes. By helping to control moisture-related operational problems, the systems support plant efficiency and help reduce the potential for costly unplanned shutdowns.
PSB’s skid-mounted LNG dehydration systems are custom designed with single- to multi-layered-bed configurations to accommodate varying process parameters, meet stringent outlet-water requirements, and provide ease of on-site installation. The systems are designed for flows from 1 to 200 MMSCFD, pressures from 150 to 1450 psig, and temperatures from 50 to 122°F, with outlet water content of less than 1 ppmv and a dew point of less than −100°C (−148°F).
The dehydration systems are closed looped with zero gas emissions/gas losses for water removal. They are automatic and heat regenerative, using dry product gas for regeneration and either an electric or gas-fired heater as the heat source. Gas cooling can be provided by an air cooler or shell-and-tube heat exchanger. PSB can also provide heat-integration options with upstream and/or downstream compression to optimise overall operating cost.
High-efficiency coalescing and particulate filters are installed upstream and downstream of the TSA vessels. The upstream filters protect adsorbent media from aerosols, while downstream filters protect equipment from dust and particulates.
For applications that require heavy hydrocarbon removal, PSB offers skid-mounted TSA-based systems designed to remove C6+, naphthalene, benzene and toluene from the gas stream. Removing these heavy hydrocarbons helps address the risk of freeze-up in downstream liquefaction trains and plate-and-fin heat exchangers and, in some cases, off-spec product gas.
PSB’s HHC-removal systems are designed for small-scale LNG and peak-shaving LNG plants. With open-, semi-closed- or closed-loop regeneration, these skid-mounted systems provide a highly cost-effective, minimal-footprint option for applications facing budget and real-estate constraints. The systems are designed for flows from 1 to 100 MMSCFD, pressures from 430 to 1,200 psig, temperatures from 50 to 122°F, and outlet water content of less than 0.1 to 1 ppmv.
HHC removal can be combined with moisture removal using a multi-layered-bed design, offering an optimised design that saves CAPEX and footprint. Through customised skid-mounted systems that can combine moisture removal and HHC removal in a multi-layered-bed design, PSB addresses the challenges behind removing these impurities and addresses stringent gas-treatment requirements before liquefaction.
These systems are fabricated, assembled, tested, painted and sandblasted “under one roof” at PSB’s 350 000 ft2 facility in Erie, Pennsylvania which helps control project cost, schedule and risk.
