FILTRATION services company Pall Corporation has recommended three different types of filtration and purification devices for liquefied natural gas producers which it says will increase plant reliability.
To be employed at different stages in the LNG liquefaction process, the company said effective application of liquid/gas (L/G) coalescers, particulate filters and liquid/liquid coalescers could also enhance plant safety and profitability.
“Due to the variability in LNG plant designs, it is recommended that designers, contractors and end users work with an experienced filtration products and services provider to ensure that their critical fluid clarification needs are met,” the company said.
L/G coalescers are designed to remove fine liquid aerosol droplets from a gas flow – offering high efficiency aerosol removal in the 0.1 to 10 micron range down to outlet levels of 0.01 ppmv, far greater than capabilities of older demister, vane pack and filter-separator technologies.
It was recommended that LNG producers use particulate filters with stable pore designs which exhibit a Beta rating of 1000 (ratio of particles entering / particles leaving the filter at a specified micron size) or higher, in order to ensure continued particle retention throughout the filter’s service life.
Filters that exhibit unloading will allow slugs of particulate downstream, creating fouling issues. Rental skids are recommended to rapidly address upset conditions in the field.
The third, L/L coalescers, remove fine droplets from a liquid flow and are effective on submicron-sized aerosols, providing downstream quality as low as 15 parts per million by volume.
Liquid loadings of up to 10 per cent by volume are treatable.