Anaerobic conversion of the hydrothermal liquefaction aqueous phase: fate of organics and intensification with granule activated carbon/ozone pretreatment

This study focuses on the valorization of the organic fraction of municipal solid waste (biopulp) by hydrothermal liquefaction. Thereby, homogeneous alkali catalysts (KOH, NaOH, K2CO3, and Na2CO3) and a residual aqueous phase recirculation methodology were mutually employed to enhance the bio-crude yield and energy efficiency of a sub-critical hydrothermal conversion (350 °C, 15–20 Mpa, 15 min). Interestingly, single recirculation of the concentrated aqueous phase positively increased the bio-crude yield in all cases, while the higher heating value (HHV) of the bio-crudes slightly dropped. Compared to the non-catalytic experiment, K2CO3 and Na2CO3 effectively increased the bio-crude yield by 14 and 7.3%, respectively. However, KOH and NaOH showed a negative variation in the bio-crude yield. The highest bio-crude yield (37.5 wt.%) and energy recovery (ER) (59.4%) were achieved when K2CO3 and concentrated aqueous phase recirculation were simultaneously applied to the process. The inorganics distribution results obtained by ICP reveal the tendency of the alkali elements to settle into the aqueous phase, which, if recovered, can potentially boost the circularity of the HTL process. Therefore, wise selection of the alkali catalyst along with aqueous phase recirculation assists hydrothermal liquefaction in green biofuel production and environmentally friendly valorization of biopulp.

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The application of activated carbon for the treatment and reuse of the aqueous phase derived from the hydrothermal liquefaction of a halophytic Tetraselmis sp.

Bioresource Technology ◽

10.1016/j.biortech.2015.01.129 ◽

2015 ◽

Vol 182 ◽

pp. 378-382 ◽

Cited By ~ 9

Author(s):

Mason Erkelens ◽

Andrew S. Ball ◽

David M. Lewis

Keyword(s):

Activated Carbon ◽

Aqueous Phase ◽

Hydrothermal Liquefaction

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Bio-Crude Production through Recycling of Pretreated Aqueous Phase via Activated Carbon

Energies ◽

10.3390/en14123488 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3488

Author(s):

Ayaz Ali Shah ◽

Saqib Sohail Toor ◽

Asbjørn Haaning Nielsen ◽

Thomas Helmer Pedersen ◽

Lasse Aistrup Rosendahl

Keyword(s):

Activated Carbon ◽

Sewage Sludge ◽

Aqueous Phase ◽

Energy Recovery ◽

Heterocyclic Compounds ◽

Solid Phase ◽

Hydrothermal Liquefaction ◽

Inorganic Elements ◽

Commercial Scale ◽

Small Chain

The management and optimization of the aqueous phase are the major challenges that hinder the promotion of hydrothermal liquefaction (HTL) technology on a commercial scale. Recently, many studies reported about the accumulation of the N-content in the bio-crude with continuous recycling of the aqueous phase from high protein-containing biomass. In the present study, sewage sludge was processed at 350 °C in an autoclave. The produced aqueous phase was treated with activated carbon, and its subsequent recycling effect on the properties of the bio-crude and aqueous phase was investigated. By contacting the aqueous phase with activated carbon, 38–43% of the total nitrogen was removed from the aqueous phase. After applying the treated aqueous phase recycling, the energy recovery of the bio-crude increased from 50 to 61% after three rounds of recycling. From overall carbon/nitrogen recoveries, 50 to 56% of the carbon was transferred to the bio-crude phase and more than 50% of the nitrogen remained in the aqueous phase. The aqueous phase contained mostly of N&O-heterocyclic compounds, small chain organic acids, and amides. ICP-AES analysis showed that more than 80% of the inorganic elements were concentrated into the solid phase.

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Reducing Nitrogen Content in Bio-Oil from Circulating Hydrothermal Liquefaction of Spirulina Platensis by Treating the Recycled Aqueous Phase with Activated Carbon

SSRN Electronic Journal ◽

10.2139/ssrn.3919668 ◽

2021 ◽

Author(s):

Yibing Duan ◽

Bo Zhang ◽

Zhixia He ◽

Bin Wang ◽

Haitao Chen

Keyword(s):

Activated Carbon ◽

Nitrogen Content ◽

Aqueous Phase ◽

Spirulina Platensis ◽

Hydrothermal Liquefaction ◽

Bio Oil

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Hydrothermal liquefaction of municipal wastewater sludge and nutrient recovery from the aqueous phase

Biofuels ◽

10.1080/17597269.2020.1863627 ◽

2021 ◽

pp. 1-6

Author(s):

Vinod Kumar ◽

Krishna Kumar Jaiswal ◽

Mikhail S. Vlaskin ◽

Manisha Nanda ◽

M. K. Tripathi ◽

...

Keyword(s):

Aqueous Phase ◽

Municipal Wastewater ◽

Hydrothermal Liquefaction ◽

Wastewater Sludge ◽

Nutrient Recovery

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Pretreatment of Switchgrass for Production of Glucose via Sulfonic Acid-Impregnated Activated Carbon

Processes ◽

10.3390/pr9030504 ◽

2021 ◽

Vol 9 (3) ◽

pp. 504

Author(s):

Yane Ansanay ◽

Praveen Kolar ◽

Ratna Sharma-Shivappa ◽

Jay Cheng ◽

Consuelo Arellano

Keyword(s):

Activated Carbon ◽

Sulfonic Acid ◽

Solid Acid ◽

Methanesulfonic Acid ◽

Biofuel Production ◽

Acid Catalysts ◽

Effects Of Temperature ◽

Carbon Catalysts ◽

Hydrolysis Of

In the present research, activated carbon-supported sulfonic acid catalysts were synthesized and tested as pretreatment agents for the conversion of switchgrass into glucose. The catalysts were synthesized by reacting sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid with activated carbon. The characterization of catalysts suggested an increase in surface acidities, while surface area and pore volumes decreased because of sulfonation. Batch experiments were performed in 125 mL serum bottles to investigate the effects of temperature (30, 60, and 90 °C), reaction time (90 and 120 min) on the yields of glucose. Enzymatic hydrolysis of pretreated switchgrass using Ctec2 yielded up to 57.13% glucose. Durability tests indicated that sulfonic solid-impregnated carbon catalysts were able to maintain activity even after three cycles. From the results obtained, the solid acid catalysts appear to serve as effective pretreatment agents and can potentially reduce the use of conventional liquid acids and bases in biomass-into-biofuel production.

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