32 TANKS & LOGISTICS
operations. These too have their shortcomings: cavitation or an increase in viscosity can put the pump’s rotor out of alignment. Blackmer believes that a better alternative is its LD17 series of centrifugal pumps, available in 11 models to suit different site configurations, flow rates and temperature ranges. Blackmer designed the LD17 pumps from the seal outwards, as this is where 90 per cent of pump failures occur. The pumps also feature a stiffer, heavy-duty shaft and larger bearings, which help prevent vibration damage while also delivering the widest operational window. Flow rates of up to 320 m3/hr are possible, with high-temperature models able to handle product at up to 400°C.
PHENOL IS AN important product in the chemical value chain and is widely moved in bulk around the world. It does, though, present some challenges, not least in transfer operations, due to its dermal corrosivity properties and also its high freezing point of 32°C. As it falls towards that temperature, it becomes viscous, causing problems with pumping.
temperature, while also being able to prevent leaks and spills. In the past, sealed ANSI centrifugal pumps have been in general use in phenol transfer operations. The drawback of these basic types of pump lies in the mechanical seals, which can fail through vibration or as a result of the radial load that they experience. Not only is this expensive, with seals costing around
CHANGE FOR THE BETTER Blackmer reports a successful installation of its LD17 pumps at a phenol producing plant in the north-east US, which had been experiencing repeated failures in the mechanical seals on its centrifugal pumps. The pump was sited in a corner of the facility, where off-spec phenol was transferred to a bottoms tank for later re-use in the production process as needed. The company found that, at temperatures close to its freezing point, the pump would experience vibration and radial deflection of its impeller and shaft, leading to seal damage. There was also an issue with the location of the pump: in the case of seal failure, a leak might not be spotted for some time, allowing phenol to leak to the ground; in winter this would freeze while in summer it would gather in a slushy puddle. In either case, it was difficult to clear up and posed a health hazard for workers. The operator decided to replace its existing pump with a Blackmer LD17 unit, as it had
In particular, pumps and piping used to move phenol have to have steam jacketing in order to prevent the phenol crystallising and freezing, which would stop the pump from working and also necessitate a tricky cleaning job. As such, pumps need to have an optimised flow rate and maintain a high
$3,000 each, but it presents a hazard, since the pump will need to be flushed and cleaned of phenol before it can be handled to replace the seal. Some operators have avoided these issues by using a seal-less pump, such as a canned-motor pump, in phenol transfer
experience with the brand in other applications. The new pump, fitted with double mechanical seals, was installed in 2017 and has operated without issue since then, with no leaks reported and no need to replace any of the seals. www.blackmer.com
A STICKY PROBLEM PUMPS • OPERATORS HANDLING PHENOL KNOW IT CAN BE A TRICKY SUBSTANCE TO TRANSFER. THAT IMPOSES GREAT STRESSES ON THE PUMPS USED, SOMETHING THAT BLACKMER IS ADDRESSING
HCB MONTHLY | JULY-AUGUST 2022
