Established plants for the desulphurisation of fuels by filtration with amine are unfortunately often outdated and neglected, but today filtration can be implemented much more efficiently. Filtration technologies actually play an important role in the performance of amine plants and have evolved significantly since their development and introduction into production. These improvements have an impact on both maintenance and reliability. But more importantly, they can provide a cost-effective route to operator safety while significantly reducing environmental impact.
All this, plus an ever-increasing number of processes, makes amine plants an increasingly important element in fuel production and the associated production of sour gas. ‘Given their importance, it would be logical for amine plants to be at the top of any list of technical upgrades, but we are far from that today. The truth is that most plants currently in operation are older and often neglected, with outdated technologies and mediocre efficiency,’ writes Cyril Coutures (Eaton Corporation) in the October issue of Chemie Technik.
Inadequate filtration is the most obvious cause of many maintenance problems. Perhaps the most common symptom is blockage of the activated carbon filter, usually indicated by an increase in differential pressure in the filter due to excessive contamination. In almost all cases, the cause is poor performance of the upstream filter. To extend run times and reduce maintenance costs and associated downtime, low-efficiency filter media is used, according to Cyril Coutures’ analysis.
Improving Efficiency Through Modern Technology
The impact of inappropriate filtration technology that is most likely overlooked is that on the heat exchanger. Because the pipe that transports rich amine is often completely unprotected, contaminants collect in the heat exchanger’s housing and pipes – resulting in unplanned maintenance to clean these elements.
With today’s technologies, such problems can be completely avoided. The typical configuration used in virtually every plant offers some opportunities for improvement in terms of efficiency, environmental impact and, more importantly, operator safety. The use of filtration technology in the form of a backwash filter with automatic self-cleaning significantly optimises the points described.
During operation, contaminants accumulate on the outside of the filter media, forming a particle cake that gradually increases the differential pressure in the filter. Once the differential pressure reaches a preset value, the flow through the filter is reversed to remove and flush out the dirt particle cake. The advantage for operator safety is obvious. If a filter does not need to be opened, operators do not need to be in a hazardous environment and the likelihood of accidents is minimal.
The second advantage of a self-cleaning backwash filter is an economic one. There are no filter cartridges or filter bags to replace and dispose of – and all the associated costs are simply eliminated. The same applies to the costs of the associated downtime and the labour involved in changing them.
In this way not only can operating costs be reduced and the environmental impact minimised, but the operating time of the amine plant can also be extended.