Aqueous phase recirculation during hydrothermal carbonization of microalgae and soybean straw: A comparison study

Leng, Songqi; Li, Wenting; Han, Chao; Chen, Linlin; Chen, Jie; Li, Fan; Lu, Qian; Jun, Li; Leng, Lijian; Zhou, Wenguang

doi:10.1016/j.biortech.2019.122502

Cited by 85 publications

(22 citation statements)

References 45 publications

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“…Soybean straw contains a low amount of ash, the proximate analysis of soybean straw well matches with another soybean straw feedstock as previously reported by Huang et al (2016). The calorific value of soybean straw was observed to be about 14.00 MJ/kg, which found very closer to the other agricultural residues (Dos Santos et al 2018;Leng et al 2020) Ultimate analysis results of soybean straw revealed that a percentage of oxygen to be around (47.53±0.02%), carbon (44.64±0.02%), hydrogen (6.79±0.12%), and a negligible percentage of nitrogen (0.94±0.01%), and sulfur content (0.10±0.32%). While, hydrogen to carbon, oxygen to carbon, and nitrogen to carbon ratios were obtained using empirical formula are 1.34±0.01, 0.83±0.01, 52.98±1.22.…”

Section: Characteristics Of Soybean Straw Biomasssupporting

confidence: 85%

Influence of Model Free Methods on Pyrolysis Kinetics and Thermodynamic Parameters of Soybean Straw

Jagtap

Kalbande

2021

Preprint

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Thermochemical conversion of surplus agro-residue for energy generation has gained renewed attention, due to its abundant availability throughout the world. Although, it still needs the thermodynamic and pyrolysis kinetic background, that play important role for the effectual design of thermo-chemical conversion reactors such as pyrolyzers, gasifiers, etc. In the present study, thermal profile (mass loss vs. temp) for soybean straw was examined at 20, 30, 40 oC/min heating rates under a non-isothermal condition in an oxygen limiting environment through a thermogravimetric analyzer (TGA). The pyrolysis kinetic parameters (activation energy and pre-exponential factor) were evaluated by applying iso-conversional model-free methods such as Flynn–Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink. The average values of activation energy for KAS, FWO and Starink models were recorded to be around 150, 155 and 147 kJ/mol, respectively. Thermodynamic variables (change of enthalpy, entropy, and Gibbs free energy) for soybean straw were also computed. The average value of enthalpy for FWO, KAS, Starink were recorded to be 151, 147, and 142 kJ/mol, respectively. The obtained simulation findings of pyrolysis kinetic and thermodynamic variables are in good agreement.

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Section: Characteristics Of Soybean Straw Biomasssupporting

confidence: 85%

Influence of Model Free Methods on Pyrolysis Kinetics and Thermodynamic Parameters of Soybean Straw

Jagtap

Kalbande

2021

Preprint

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“…After recirculation steps, as it can be observed, the hydrogen (H) and nitrogen (N) contents remained almost unchanged, as commonly observed during HTC of lignocellulosic waste biomass [59]. Differently, carbon (C) and fixed carbon (FC) contents increased while oxygen (O) and volatile matter (VM) contents decreased [46,66,67,73]. These findings confirm that the hydrochars are further converted into solid fuel by HTC with recirculated PW.…”

Section: Effect On Chemical Compositionsupporting

confidence: 78%

Process Water Recirculation during Hydrothermal Carbonization of Waste Biomass: Current Knowledge and Challenges

2021

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Hydrothermal carbonization (HTC) is considered as an efficient and constantly expanding eco-friendly methodology for thermochemical processing of high moisture waste biomass into solid biofuels and valuable carbonaceous materials. However, during HTC, a considerable amount of organics, initially present in the feedstock, are found in the process water (PW). PW recirculation is attracting an increasing interest in the hydrothermal process field as it offers the potential to increase the carbon recovery yield while increasing hydrochar energy density. PW recirculation can be considered as a viable method for the valorization and reuse of the HTC aqueous phase, both by reducing the amount of additional water used for the process and maximizing energy recovery from the HTC liquid residual fraction. In this work, the effects of PW recirculation, for different starting waste biomasses, on the properties of hydrochars and liquid phase products are reviewed. The mechanism of production and evolution of hydrochar during recirculation steps are discussed, highlighting the possible pathways which could enhance energy and carbon recovery. Challenges of PW recirculation are presented and research opportunities proposed, showing how PW recirculation could increase the economic viability of the process while contributing in mitigating environmental impacts.

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“…The color of the culture and the morphology characteristics of the Chlorella strains are detailed in Figure 1. The OD 680 is used to measure the growth of microalgae, including Chlorella, in many previous studies (Leng et al, 2020;Vu et al, 2020). Herethe OD 680 of three strains at stationary phase was lower than 2.00, the maximum OD 680 value under photoautotrophic conditions (optical density at 680 nm: KNUA104, 1.42 ± 0.01; KNUA114, 1.77 ± 0.02; KNUA122, 1.74 ± 0.02).…”

Section: Effects Of Culture Conditions On Microalgal and Cell Morphologymentioning

confidence: 93%

“…As an alternative to measuring cell density by OD 680 value, the color of the culture was recorded for each sample. There was a change in the microalgae culture for each cultivation condition we applied, and this also occurred in the pigment (Leng et al, 2020;Vu et al, 2020). During log-phase growth, the color of the culture for samples grown under mixotrophic conditions is generally more intense compared to samples grown under heterotrophic conditions the color of the culture varying according to the initial glucose concentration.…”

Section: Effects Of Culture Conditions On Microalgal and Cell Morphologymentioning

confidence: 98%

Effect of Different Cultivation Modes (Photoautotrophic, Mixotrophic, and Heterotrophic) on the Growth of Chlorella sp. and Biocompositions

Yun¹,

Kim²,

Yoon³

2021

Front. Bioeng. Biotechnol.

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In the past, biomass production using microalgae culture was dependent on inorganic carbon sources as microalgae are photosynthetic organisms. However, microalgae utilize both organic and inorganic carbon sources, such as glucose. Glucose is an excellent source of organic carbon that enhances biomass yield and the content of useful substances in microalgae. In this study, photoautotrophic, mixotrophic, and heterotrophic cultivation conditions were applied to three well-known strains of Chlorella (KNUA104, KNUA114, and KNUA122) to assess biomass productivity, and compositional changes (lipid, protein, and pigment) were evaluated in BG11 media under photoautotrophic, mixotrophic, and heterotrophic conditions utilizing different initial concentrations of glucose (5, 10, 15, 20, and 25 g L−1). Compared to the photoautotrophic condition (biomass yield: KNUA104, 0.35 ± 0.04 g/L/d; KNUA114, 0.40 ± 0.08 g/L/d; KNUA122, 0.38 ± 0.05 g/L/d) glucose was absent, and the biomass yield improved in the mixotrophic (glucose: 20 g L−1; biomass yield: KNUA104, 2.99 ± 0.10 g/L/d; KNUA114, 5.18 ± 0.81 g/L/d; KNUA122, 5.07 ± 0.22 g/L/d) and heterotrophic conditions (glucose: 20 g L−1; biomass yield: KNUA104, 1.72 ± 0.26 g/L/d; KNUA114, 4.26 ± 0.27 g/L/d; KNUA122, 4.32 ± 0.32 g/L/d). All strains under mixotrophic and heterotrophic conditions were optimally cultured when 15–20 g L−1 initial glucose was provided. Although bioresourse productivity improved under both mixotrophic and heterotrophic conditions where mixotrophic conditions were found to be optimal as the yields of lipid and pigment were also enhanced. Protein content was less affected by the presence of light or the concentration of glucose. Under mixotrophic conditions, the highest lipid content (glucose: 15 g L−1; lipid content: 68.80 ± 0.54%) was obtained with Chlorella vulgaris KNUA104, and enhanced pigment productivity of Chlorella sorokiniana KNUA114 and KNUA122 (additional pigment yield obtained with 15 g L−1 glucose: KNUA 114, 0.33 ± 0.01 g L−1; KNUA122, 0.21 ± 0.01 g L−1). Also, saturated fatty acid (SFA) content was enhanced in all strains (SFA: KNUA104, 29.76 ± 1.31%; KNUA114, 37.01 ± 0.98%; KNUA122, 33.37 ± 0.17%) under mixotrophic conditions. These results suggest that mixotrophic cultivation of Chlorella vulgaris and Chlorella sorokiniana could improve biomass yield and the raw material quality of biomass.

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Aqueous phase recirculation during hydrothermal carbonization of microalgae and soybean straw: A comparison study

Cited by 85 publications

References 45 publications

Influence of Model Free Methods on Pyrolysis Kinetics and Thermodynamic Parameters of Soybean Straw

Influence of Model Free Methods on Pyrolysis Kinetics and Thermodynamic Parameters of Soybean Straw

Process Water Recirculation during Hydrothermal Carbonization of Waste Biomass: Current Knowledge and Challenges

Effect of Different Cultivation Modes (Photoautotrophic, Mixotrophic, and Heterotrophic) on the Growth of Chlorella sp. and Biocompositions

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