The first plant Fuelling Sustainability (FS) plant started its initial phase of production in 2017 with an initial capacity of 250 million litres per year. In addition to bioethanol, the plant produces coproducts such as corn oil as well as high-protein and high-fibre dried distiller’s grains. It also generates electricity from the biomass, partly for internal use and the surplus for sale.
Each step of ethanol production from corn involves pumps with technically demanding applications. The liquids can be complex, have high solids contents, be viscous, corrosive, hot, erosive, or explosive. The right pump materials and optimal sealing systems must be selected to ensure reliable and long-lasting operation. Furthermore, all pumps must be highly efficient in terms of energy and water savings, so that the complete plant is operating to its full potential.
The delivery included Ahlstar and SNS pumps for all applications – from initial mash slurry transfer to final ethanol truck loading. In total, more than 80 single-stage pumps were installed for phase 1. The Ahlstar pumps in duplex material are handling liquids containing solids and other particles, while the SNS pumps are running on clean liquids. Most of the pumps are equipped with double mechanical seals.
For the toughest applications, the Ahlstar pumps with adjustable side plates perform continuously. For clean liquids, the new SNS pumps are said to exceed the benchmark efficiency index MEI 0.7.
Both types of pumps have open impellers with balancing holes that optimise the shaft seal function. For pumps with double mechanical seals, it was decided after a few months’ operation to switch from API piping plan 54 (external pressurized source) to API piping plan 53 (external pressurized reservoir). This change helped to further reduce the water consumption and operational costs. The Sulzer service technicians carried out the upgrade.
In 2018, a duplicate of the existing plant was built (phase 2). FS ordered new similar Sulzer pumps for this extension. The site was further expanded in 2019 (phase 3) with additional Sulzer equipment installed.
Most Ahlstar pumps with double seal are equipped with the Sulzer thermosiphon SP8 seal pot system. The Ahlstar and SNS pump ranges have a wide choice of wet end sizes to cover the required flows (2 to 1’230 m³/h) and heads (4 to 105 m). This allows the pumps to always run at duty points close to the best efficiency points.