SEAWEED EXTRACT
Pumping Highly Viscous Seaweed Extracts at High Temperatures
How to ensure stable processing after decanting
Conveying decanted seaweed extract places high demands on the pumps used. Due to its high viscosity, pasty consistency, and structured nature, the medium has limited flowability and is processed at high temperatures and under alkaline conditions. A Canadian company was faced with precisely this challenge. The aim was to convey the decanted seaweed extract from the centrifuge to the packaging area in a process-reliable, odour-free manner and with reasonable maintenance costs.
This is where NETZSCH Pumps & Systems came into the picture. The global specialist in handling complex media developed a solution optimally tailored to the company’s requirements for processing seaweed extract. We will show you how to ensure stable, economical pumping even under demanding process conditions.
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High demands when pumping seaweed extract
The extract obtained from the Ascophyllum nodosum seaweed species poses particular challenges for conveying technology after dewatering. The medium has a very viscous, gelatinous consistency and, rheologically, lies in the transition zone between the solid and liquid states. In addition, a solid content of more than 25 percent and a density of approximately 1.2 kg/dm³ make uniform conveying difficult. Process-related constraints further complicate matters. The extract leaves the centrifuge at temperatures of up to 90 °C and has a high pH value pH value pH value due to the alkaline process media used. For operators, this means a combination of thermal, chemical and mechanical stress on the conveyor technology used.
Limited process control due to open conveyor technology
Initially, the decanted seaweed extract was transported from the centrifuge outlet to the package area using an open mechanical conveyor. However, this solution proved to be inflexible and difficult to control. In addition, the open design led to odour emissions in the production area and made it difficult to maintain clean process control. Since a progressing cavity pump was already in use to feed the centrifuge, the operator was specifically seeking a closed, pressure-stable solution for further transport. What was required was a conveying system operating reliably even with varying intake quantities and changing pressure conditions.
Pump solution for stable and continuous process control
The decision to use the NEMO® BF hopper shaped pump with feeding screw was based on a combination of design features specifically tailored to the processing of highly viscous, pasty and structured media. The open hopper with an integrated feeding screw ensures active, controlled insertion of the seaweed extract into the pump chamber. This ensures continuous and reliable conveyance even with poorly flowing, non-self-sliding media. A special screw geometry leads to controlled overfilling of the pump chamber. This effect homogenises the extract even before the actual conveyance process and ensures a uniform volume flow without segregation or unstable conveyance conditions. In addition, the feeding screw protrudes beyond the connection area on both the drive and Rotorrotor,Rotors,rotorsrotor sides. This consistently prevents dead zones, reducing the risk of deposits, product decomposition and unwanted downtime.
The pump components coming into contact with the media are made of stainless steel and are therefore resistant to the alkaline media used in the process. This increases operational reliability even under changing process conditions and contributes to long-term plant availability. A food-grade stator and a stuffing box complemented the design. During a pump test at the production plant, the pump also reliably handled temporary pressure increases, for example, when supplying two packaging areas simultaneously through a split-discharge hose. This eliminated the need for a second parallel conveyor line, reducing the system’s complexity and simplifying production logistics. Today, the operator benefits from closed, odour-free conveyance of the seaweed extract throughout the entire plant. The conveying capacity achieved in continuous operation corresponds precisely to the values previously determined in test operation. At the same time, manual intervention in the process has been reduced, and packaging flexibility has been significantly increased.
Contact the experts at NETZSCH Pumps & Systems to design an efficient pump solution for your application. We will be happy to assist you in analysing your process requirements.
NEMO® BF hopper shaped pump with feeding screw
- Medium: Decanted seaweed extract
- Capacity: 23 m³/h
- Pressure: 3 bar
- Speed: 43 rpm
- Temperature: Up to 90 °C
- Other: Approximately 25 % solids content
