Hydrocarbons from Spirulina Pyrolysis Bio-oil Using One-Step Hydrotreating and Aqueous Extraction of Heteroatom Compounds

Abstract

Biomass feedstocks such as algae and cyanobacteria are highly sought after because of their high reproduction rates and growth densities, but their high concentrations of O and N heteroatoms are problematic for biofuel applications. Mild upgrading processes are necessary for producing fungible fuels from these renewable sources. We developed a process to upgrade spirulina-based bio-oil from tail-gas reactive pyrolysis (TGRP), using a combination of catalytic hydrotreatment and purification of the upgraded product. The TGRP bio-oil was distillated at high organic yields, and the distillates served as the feedstock for catalytic upgrading. Simultaneous hydrodeoxygenation and hydrodenitrogenation (HDO/HDN) was carried out in one step using a commercial ruthenium catalyst on carbon support. Using bio-oil distillates as feedstocks for hydrotreatment produced hydrocarbons at high space velocities. Reactor temperature was the critical variable, wherein the optimal temperature compromised between excessive yields loss and catalyst inactivity. While the HDO/HDN product contained relatively significant amounts of residual O and N (∼1 wt % each), the remaining O and N-containing compounds were removed via single aqueousphase extraction with hydrochloric acid. The extraction step serves as a milder alternative to deep HDO/HDN processes that diminish final product yields.

Optimization to Hydrothermal Liquefaction of Low Lipid Content Microalgae Spirulina sp. Using Response Surface Methodology

“…e supply of Spirulina as the functional food has much exceeded the demand. Some studies showed the possibility of producing bio-oil using Spirulina by liquefaction technology [19][20][21][22]. If biooil is to be obtained efficiently from mass-cultivated Spirulina by liquefaction, this will be one of the both promising methods for energy production and one of the Spirulina consumption.…”

Cyanobacteria as an eco‐friendly resource for biofuel production: A critical review

“…Nevertheless, the biomass of cyanobacteria is valuable for biofuel production, the high viscosity and O and N heteroatomic of their contents (protein and lipid) encounter their bio-oil production with some difficulties. Performing the TGRP technology with the combination of hydrodeoxygenation and hydrodenitrogenation (HDO/HDN) and final extraction with hydrochloric acid would be operative for the generation of clean hydrocarbon from Spirulina biomass 93. Velmurugan et al94 utilized different metal oxides (Al 2 O 3 , CaO, MgO, and ZnO) in individual, binary, and ternary forms for the extraction of glycogen and lipid contents from Synechocystis sp.…”

Catalytic Thermochemical Conversion of Algae and Upgrading of Algal Oil for the Production of High-Grade Liquid Fuel: A Review

“…The quality of pyrolytic bio-oil needs to be upgraded via catalytic process before utilization as transportation fuel. Elkasabi et al investigated one-step hydrotreating and aqueous extraction of O and N-containing compounds, for the production of fuel-range hydrocarbons from Spirulina pyrolysis bio-oil [142]. The catalytic hydrodeoxygenation (HDO) and hydrodenitrogenation (HDN) were conducted over commercial Ru/C catalyst.…”