Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8085822 | Algal Research | 2018 | 8 Pages |
Abstract
Hydrothermal liquefaction (HTL) is a promising technique for crude bio-oil (biocrude) production from microalgae. Instead of traditional direct HTL at one temperature with a residence time, the present work explored two temperature steps (TTS) and more temperature steps (MTS) of microalgae (Chlorella) HTLs for the first time in mini-batch reactors. Specifically, the reactions for the TTS of HTL were performed at a relatively low temperature (150-300â¯Â°C) for 10-40â¯min and then at a high temperature (350â¯Â°C) for 10-20â¯min. In the MTS of HTL, three or four temperature steps were adopted and each temperature stage (within 150-300â¯Â°C) was kept for 10â¯min. The results show that the low temperature pre-reaction stage significantly affected the yield, elemental composition, higher heating value, energy recovery and molecular component of biocrude. The biocrude derived from the TTS of HTL of 250*20-350 (i.e., a pre-reaction at 250â¯Â°C for 20â¯min followed by a HTL at 350â¯Â°C for 10â¯min) had the highest H content (9.00â¯wt%) and the lowest S content (0.55â¯wt%). Its yield, elemental composition, higher heating value, and energy recovery were comparable with those of the biocrude from the direct HTL at 350â¯Â°C for 30â¯min (with the highest yield and the best quality in tests). In comparison to direct HTL, a proper TTS of microalgae HTL was able to reduce reaction temperature on the premise of ensuring similar biocrude properties, so might be applicable in the algal bio-oil production.
Related Topics
Physical Sciences and Engineering
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Renewable Energy, Sustainability and the Environment
Authors
Zhen He, Donghai Xu, Liang Liu, Yang Wang, Shuzhong Wang, Yang Guo, Zefeng Jing,