Combination Concentrating Candle Filters and Pressure Plate Filters for Removing Divalent Salts and Contaminants from Monoethylene Glycol Reclamation Units
For the transport of Liquefied Natural Gas (LNG), monoethylene glycol (MEG) is injected as corrosion inhibitor and to reduce the freezing point of the water in the LNG. In the reclamation unit, rich MEG is converted to lean MEG. During MEG reclamation, the divalent salt concentration increases and these salts reduce the efficiency of the process and must be removed. This paper discusses a combination solid-liquid filtration system for as an alternative to thickeners, centrifuges, filter presses and cartridges. The rich MEG solids slurry is first concentrated using candle filters for a solids-free filtrate and a concentrated sludge of approximately 4-5 % solids. Next, pressure plate filters are used to wash and dry the cake to produce an MEG-free cake for non-hazardous disposal. The paper discusses laboratory tests, continues with case histories and concludes with the information that engineers need before deciding on a solid-liquid separation technology.
This is a PDF document: click here to download and view this document.