Hydrothermal liquefaction of Malaysia's algal biomass for high‐quality bio‐oil production

Abstract

Currently, fossil materials form the majority of our energy and chemical source. Many global concerns force us to rethink about our current dependence on the fossil energy. Limiting the use of these energy sources is a key priority for most countries that pledge to reduce greenhouse gas emissions. The application of biomass, as substitute fossil resources for producing biofuels, plastics and chemicals, is a widely accepted strategy for sustainable development. Aquatic plants including algae possess competitive advantages as biomass resources compared to the terrestrial plants in this current global situation. Bio‐oil production from algal biomass is technically and economically viable, cost competitive, requires no capacious lands and minimal water use and reduces atmospheric carbon dioxide. The aim of this paper is to review the potential of converting algal biomass, as an aquatic plant, into high‐quality crude bio‐oil through applicable processes in Malaysia. In particular, bio‐based materials and fuels from algal biomass are considered as one of the reliable alternatives for clean energy. Currently, pyrolysis and hydrothermal liquefaction (HTL) are two foremost processes for bio‐oil production from biomass. HTL can directly convert high‐moisture algal biomass into bio‐oil, whereas pyrolysis requires feedstock drying to reduce the energy consumption during the process. Microwave‐assisted HTL, which can be conducted in aqueous environment, is suitable for aquatic plants and wet biomass such as algae.

Characterization and Analysis of Malaysian Macroalgae Biomass as Potential Feedstock for Bio-Oil Production

“…Hence, algal biomass is considered to have a greater potential compared with terrestrial lignocellulosic biomass, specifically for biofuels production. Hence, algae biomass are described as the most suitable feedstocks for next-generation biofuels production and chemicals synthesis [2,3]. Generally, algae are categorised into two types, which are microalgae and macroalgae.…”

“…Microalgae have relatively gained more attention in the research field. However, macroalgae also have indisputable potential to be developed and improved for bio-based substance production [2]. Nevertheless, there is still a lack of research works related to the conversion of these low-lipid algae, especially macroalgae (usually called seaweed) into crude bio-oil production.…”

“…In Malaysia, Sabah, or more specifically Semporna, is the major seaweed production area. The development of seaweed production has been enhanced from time to time, and eventually, seaweed has become an important natural resource for Malaysia in term of economic development [2]. Hence, the algae supply in Malaysia is reliable and remains to have a huge potential for utilisation.…”

“…As mentioned previously, due to the tropical weather in Malaysia, Malaysia has provided a suitable living environment for various kinds of algal species. Hence, Malaysia has huge algae resources and should be continuously discovered [2]. In this paper, the potentiality of macroalgae/seaweed (Caulerpa lentillifera, Gracilaria coronopifolia, and Chaetomorpha linum) to be used as renewable biomass feedstock was investigated.…”

Key Targets for Improving Algal Biofuel Production

“…Microwave assisted HTL has also been examined [109], as has the application of HTL using macroalgae [110]. However, the economy of the process is still questionable due to the utilization of higher pressure conditions.…”