TECH FILE: The SERO SHPmarine Pump for Dual Fuel Propulsion Systems
While the maritime industry steams toward alternative and dual fuel solutions, much of the focus, rightfully so, remains on the main movers as well as the overall vessel design and logistics considerations. Here we look at the SERO PumpSystems’ SHPmarine side channel pump, a pump integrated into the “Secondary Fuel Supply Systems” (SFSS) of hybrid ship propulsion units pumping LPG (propane) to the main shipboard engine.
According to the manufacturer, it is the first pump of its kind to be both Lloyd's Register accepted and DNV GL type approved for maritime dual fuel propulsion systems. This pump includes: a low suction head requirement, uninterrupted pressure-constant delivery of low-viscosity liquids and a resistance to shipboard vibrations ensuring high functional reliability of the SHPmarine in "over the water" applications.
The SHPmarine pump technology was originally developed for use in the oil and gas industry, handling natural gas liquids in a myriad of midstream production and process services. It has now been modified to meet maritime needs as the IMO 2020 initiative to reduce fugitive emissions takes hold.
A Seaworthy Side Channel Pump
Low NPSHr (Net Positive Suction Head requirement), reliable and pressure-constant delivery of volatile LPG and resistance to vibrations from the ship’s hull – the side channel pump SHPmarine is designed to meet all of the technical challenges when pumping LPG from the storage tanks through the SFSS feeding the main engine of an ocean going vessel.
In order to make the standard SHP seaworthy, the SHPmarine was modified according to the IMO-IGC regulations. The pressure-bearing components of the pump - such as the suction casing, the discharge casing, the outer barrel and the sealing chamber - are made of austenitic stainless steels or low-temperature steel to meet the pressure requirements.
The SHPmarine also meets the corrosive and temperature-related demands of shipboard applications. For example:
- Spring-loaded stainless steel screws and special low-temperature O-rings compensate for the thermal expansion behavior of the materials during extreme temperature changes
- A five-layer marine paint (C5M) is designed to protect the structural components from salt water and UV radiation.
- Special dry-running mechanical seals are used to prevent leakage and control fugitive emissions, and they also help to ensure cost-efficient operation and service.
To meet the unique flow and head criteria, SERO PumpSystems has extended the SHPmarine's performance range up to a 10-stage hydraulic configuration. To assist in servicing the pump, SERO integrated an all-steel spacer coupling between the pump and the drive engine. By implementing these design features, the SHPmarine was accepted by Lloyd's Register and received the type approval of DNV GL.