A Comparative Technoeconomic Analysis of Algal Thermochemical Conversion Technologies for Diluent Production

Abstract

Microalgae offer desirable attributes as a renewable feedstock. Herein, a technoeconomic assessment of using microalgae to produce chemicals (diluent) for bitumen transport is conducted. Two thermochemical technologies, hydrothermal liquefaction (HTL) and fast pyrolysis, are analyzed for a plant of 2000 dry t day−1. A detailed process model is developed for the two thermochemical conversion technologies and used to perform a data‐intensive technoeconomic assessment to estimate diluent cost using biomass. The product values of diluents from HTL and pyrolysis are 1.60 ± 0.09 and 1.69 ± 0.11 $ L−1, respectively. The sensitivity analysis indicates that product yield has the highest impact on product value, followed by the biomass cost. The effect of using industrial carbon dioxide in a situation where the producer pays to the algae conversion plant to avoid paying a carbon levy is assessed. For HTL and fast pyrolysis, diluent cost falls to 1.06 and 1.16 $ L−1, respectively, when carbon tax increases to 40 $ t−1. Herein, insights into the technoeconomic feasibility of producing chemicals from algal‐based thermochemical technologies are offered.

Roadmap for Deployment of Modularized Hydrothermal Liquefaction: Understanding the Impacts of Industry Learning, Optimal Plant Scale, and Delivery Costs on Biofuel Pricing

“…Within the aforementioned context, the present study places its thematic focus on the development of a comprehensive and systematic TEA framework, that allows also an insightful characterization of the three most impactful underlying factors (and attendant tradeoffs) on capacity planning and the 12 A simplified process flow diagram of the PNNL process can be found in Figure S2. In the current model, biocrude yield has been lowered to a more conservative 40 wt % adopted by other TEAs, 31,43,44 but all other process conditions have been left unchanged, as detailed in Table S1. A changelog of the adjustments to the PNNL model can be found in Table S7.…”

“…A simplified process flow diagram of the PNNL process can be found in Figure S2. In the current model, biocrude yield has been lowered to a more conservative 40 wt % adopted by other TEAs, ,, but all other process conditions have been left unchanged, as detailed in Table S1. A changelog of the adjustments to the PNNL model can be found in Table S7.…”

Advances and Perspectives of Bio-oil Hydrotreatment for Biofuel Production

“…To convert algae to biofuel for use in vehicle engines, the selling price of biofuel should be competitive with diesel and gasoline. The detailed estimated price of biofuel produced from different algaes at different conditions during the pyrolysis and HDO processes is shown in Table . − Bagnato et al developed a model by Aspen Plus to estimate the selling price of the biofuel (in the range of gasoline and diesel) produced through the catalytic pyrolysis followed by the hydrotreatment of Nannochloropsis and Isochrysis microalgaes derived bio-oil. Different catalysts were used in the simulation to evaluate the possibility of lowering the cost of operation.…”

A parametric study through the modelling of hydrothermal gasification for hydrogen production from algal biomass

“…[1] In addition, algae have minimal land requirements and can grow on marginal or non-arable land and even in wastewater. [3][4][5][6] Algae has commercial applications in food supplements, non-food products, aquaculture, energy, and fuel. [7] In general, there are several routes to algal conversion, including lipid extraction and conversion to biodiesel, biological processing (ie, anaerobic digestion), and thermochemical processing (ie, combustion, pyrolysis, gasification, or hydrothermal).…”

“…[20] The high diffusivity of organics in supercritical water along with the absence of phase layer boundaries results in complete reactions. [4,5] Hydrothermal gasification, as unlike traditional gasification, uses the moisture present in biomass to produce gaseous components. Moreover, hydrothermal gasification helps avoid the energy penalty associated with conventional technologies, thereby making it more economical.…”