AxFlow's pump technology for LNG dehydration
June 2008: The removal of condensate and water in the processing of LNG involves two stages: mechanical separation and dehydration, an absorption process that involves the use of glycol.
The dehydration process used by natural gas producer Noorgastransport in the North East Netherlands requires the pumping of Tri-Ethylene Glycol (TEG) through the dehydration absorption columns and this is being effectively performed by AxFlow BV's Bran + Luebbe Novaplex pumps.
AxFlow BV first introduced Novaplex N20 hydraulically actuated double diaphragm pumps to the plant some 12 years ago, replacing ageing RAM plunger pumps in order to ensure leak-free and high accuracy operation. Pumping TEG through the columns at a nominal pressure of 80 bar, the three pumps have proved to a highly successful solution and following a recent refurbishment programme AxFlow BV sees a strong future for all three pumps.
The change to diaphragm pumphead technology was made on the guidance of AxFlow's engineer's following their review of the application and how the existing pumps were performing. Using the information gathered, AxFlow were able to demonstrate the superior performance of the diaphragm pumphead technology over plunger pumps. Coupled with this, AxFlow's technical support operation put in place a programme of planned maintenance, including 24/7 emergency call-out.
Efficiency, reliability, safety and accuracy are now regarded as the essential expectations of the modern process pump and the Novaplex pump is meeting these with diaphragm pumphead technology, and in particular the hydraulically actuated double diaphragm arrangement. This pump design is perfectly suited to handling hazardous and expensive liquids such as TEG are being used says AxFlow BV.
Leak-free operation reduces the potential for environmental contamination, eliminates product waste and protects operatives from exposure to harmful materials. Most significantly, AxFlow BV reports that the Novaplex diaphragm pumphead is equally at home with low and high-pressure duties employing materials that can withstand the most aggressive liquids.
The Novaplex uses hydraulically actuated double diaphragms and the absence of sealing gaps removes the possibility of the pumped liquid leaking and thereby creating a safety problem. In addition, wear on the plungers is minimised, thereby excluding any chance of wear induced leakage. The modular phased pump heads are a significant contributor in assuring a smooth product flow regardless of the operating range.
Novaplex pumps have an integral lubrication system that does not necessitate external control or cooling. Being compact they can be easily ganged together due to their modular design and light weight, so they are ideal where space is at a premium. Most importantly, they can be run continuously 24 hours a day and demand little operator intervention and maintenance.
At the Noorgastransport plant, one pump is in continuous operation and the remaining two are run throughout winter, so at peak production all three are in operation. "It's a demanding schedule," reports Anton Bentum, AxFlow BV's field sales engineer, "and our support engineers have performed annual service throughout the working life of the pumps. By bringing our technical knowledge and experience of using diaphragm pumps in the oil and gas industry we have ensured that our customer has benefited from our original recommendations."