Energy efficient dewatering of far offshore grown green macroalgae Ulva sp. biomass with pulsed electric fields and mechanical press.

Affiliation

Porter School of Environment and Earth Sciences, Tel Aviv University, Israel. Electronic address: [Email]

Abstract

Offshore macroalgae biomass production is a promising, yet challenging, pathway to provide feedstock for biorefineries. In this work, a device and a process for dewatering offshore grown biomass of the green macroalgae Ulva sp. using high-voltage pulsed electric fields (PEF) was developed. Ulva sp. was cultivated attached to fish cages 15 km offshore. Increasing the applied voltage from 250 V to 500 V and invested PEF energy from 9.3 ± 0.4 J g-1 FW to 54.6 ± 0.2Jg-1 FW increased the extracted water from 0.033 ± 0.006 g Water g-1  FW to 0.150 ± 0.031 g Water g-1 FW. The energy consumption to achieve similar moisture content with air convection drying was lower by 78.73 ± 10.41 (JgFW-1) for 250 V and 339.31 ± 48.01 (JgFW-1) for 500 V, pulse duration 50 µs, pulse number 50, pulse repetition frequency 3 Hz. PEF leads to biomass compression of 8.45 ± 1.72% for 250 V protocol and 25.66 ± 2.53% for 500 V protocol. In addition, PEF leads to the reduction of water diffusivity of 18-19% in the treated biomass, reducing air drying kinetics.

Keywords

Electroporation,Macroalgae,Offshore biomass production,Pulsed electric fields,Seaweed drying,Ulva sp. offshore,

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