Techno-economic evaluation of microalgae harvesting and dewatering systems

F. Fasaei, J.H. Bitter, P.M. Slegers, A.J.B. van Boxtel*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

57 Citations (Scopus)

Abstract

Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like “high energy consumption” and “low in operational cost”. Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5–2 €·kg− 1 algae and 0.2–5 kWh·kg− 1 of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1–0.6 €·kg− 1 algae and the energy consumption to 0.1–0.7 kWh·kg− 1 algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation.
Original languageEnglish
Pages (from-to)347-362
JournalAlgal Research
Volume31
DOIs
Publication statusPublished - 1 Apr 2018

Fingerprint

algae
dewatering
economic analysis
microalgae
energy use and consumption
flocculation
centrifugation
flocculants
mechanical harvesting
energy resources
biomass
automation
processed foods
energy requirements
finishing
fractionation
labor
economics

Keywords

  • Cost
  • Dewatering
  • Energy
  • Harvesting
  • Microalgae
  • System analysis

Cite this

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title = "Techno-economic evaluation of microalgae harvesting and dewatering systems",
abstract = "Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like “high energy consumption” and “low in operational cost”. Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5–2 €·kg− 1 algae and 0.2–5 kWh·kg− 1 of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1–0.6 €·kg− 1 algae and the energy consumption to 0.1–0.7 kWh·kg− 1 algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation.",
keywords = "Cost, Dewatering, Energy, Harvesting, Microalgae, System analysis",
author = "F. Fasaei and J.H. Bitter and P.M. Slegers and {van Boxtel}, A.J.B.",
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Techno-economic evaluation of microalgae harvesting and dewatering systems. / Fasaei, F.; Bitter, J.H.; Slegers, P.M.; van Boxtel, A.J.B.

In: Algal Research, Vol. 31, 01.04.2018, p. 347-362.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Techno-economic evaluation of microalgae harvesting and dewatering systems

AU - Fasaei, F.

AU - Bitter, J.H.

AU - Slegers, P.M.

AU - van Boxtel, A.J.B.

PY - 2018/4/1

Y1 - 2018/4/1

N2 - Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like “high energy consumption” and “low in operational cost”. Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5–2 €·kg− 1 algae and 0.2–5 kWh·kg− 1 of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1–0.6 €·kg− 1 algae and the energy consumption to 0.1–0.7 kWh·kg− 1 algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation.

AB - Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like “high energy consumption” and “low in operational cost”. Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5–2 €·kg− 1 algae and 0.2–5 kWh·kg− 1 of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1–0.6 €·kg− 1 algae and the energy consumption to 0.1–0.7 kWh·kg− 1 algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation.

KW - Cost

KW - Dewatering

KW - Energy

KW - Harvesting

KW - Microalgae

KW - System analysis

U2 - 10.1016/j.algal.2017.11.038

DO - 10.1016/j.algal.2017.11.038

M3 - Article

VL - 31

SP - 347

EP - 362

JO - Algal Research

JF - Algal Research

SN - 2211-9264

ER -