Conversion of a wet waste feedstock to biocrude by hydrothermal processing in a continuous-flow reactor: grape pomace

Elliott, Douglas C.; Schmidt, Andrew J.; Hart, Todd R.; Billing, Justin M.

doi:10.1007/s13399-017-0264-8

Cited by 37 publications

(28 citation statements)

References 25 publications

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“…On the other hand, nitrogen was not removed to a high extent, which constitutes an issue in view of wastewater disposal. Similar results were also obtained in other studies from the same group from the processing of grape pomace [45] and wastewater solids [46].…”

Section: Aqueous Phase Processingsupporting

confidence: 90%

“…[44] and Chlorella, with both standard and high lipid content [43]. Some experience was also gained in the processing of agricultural waste, such as grape pomace [45], and of wastewater solids [46]. In general, the tests conducted at PNNL are carried out at temperatures around 350 • C and cover a wide range of dry matter concentrations, ranging from 5% up to 34.4% in the case of algae slurry.…”

Section: Pilot Plantsmentioning

confidence: 99%

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Continuous Hydrothermal Liquefaction of Biomass: A Critical Review

2018

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Hydrothermal liquefaction (HTL) of biomass is emerging as an effective technology to efficiently valorize different types of (wet) biomass feedstocks, ranging from lignocellulosics to algae and organic wastes. Significant research into HTL has been conducted in batch systems, which has provided a fundamental understanding of the different process conditions and the behavior of different biomass. The next step towards continuous plants, which are prerequisites for an industrial implementation of the process, has been significantly less explored. In order to facilitate a more focused future development, this review—based on the sources available in the open literature—intends to present the state of the art in the field of continuous HTL as well as to suggest means of interpretation of data from such plants. This contributes to a more holistic understanding of causes and effects, aiding next generation designs as well as pinpointing research focus. Additionally, the documented experiences in upgrading by catalytic hydrotreating are reported. The study reveals some interesting features in terms of energy densification versus the yield of different classes of feedstocks, indicating that some global limitations exist irrespective of processing implementations. Finally, techno-economic considerations, observations and remarks for future studies are presented.

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Section: Aqueous Phase Processingsupporting

confidence: 90%

Section: Pilot Plantsmentioning

confidence: 99%

Continuous Hydrothermal Liquefaction of Biomass: A Critical Review

2018

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Section: Introductionmentioning

confidence: 99%

“…The Pacific Northwest National Laboratory (PNNL) in the USA established a continuous HTL reactor system incorporating a continuous-flow stirred-tank reactor and a horizontal tubular reactor [16,24,26]. The system has been demonstrated for microalgae [27], macro-algae [16], food waste [26], sewage sludge and digested solids [24,28]. The main part of the system consists of a horizontal preheater with a capacity of 210 mL, a stirred tank reactor with a capacity of 415 mL where the slurry is heated to the reaction temperature (350 • C), a horizontal oil jacketed reactor (capacity 300 mL) for maintaining the slurry's temperature and a high temperature-pressure filter for removing solids at the reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

Continuous Hydrothermal Liquefaction of Biomass in a Novel Pilot Plant with Heat Recovery and Hydraulic Oscillation

et al. 2018

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Hydrothermal liquefaction (HTL) is regarded as a promising technology for the production of biofuels from biomass and wastes. As such, there is a drive towards continuous-flow processing systems to aid process scale-up and eventually commercialization. The current study presents results from a novel pilot-scale HTL reactor with a feed capacity of up to 100 L/h and a process volume of approximately 20 L. The pilot plant employs a heat exchanger for heat recovery and a novel hydraulic oscillation system to increase the turbulence in the tubular reactor. The energy grass Miscanthus and the microalgae Spirulina, both representing advanced dedicated energy crops, as well as sewage sludge as high-potential waste stream were selected to assess the reactor performance. Biomass slurries with up to 16 wt% dry matter content were successfully processed. The heat recovery of the heat exchanger is found to increase with reactor run time, reaching 80% within 5–6 h of operation. The hydraulic oscillation system is shown to improve mixing and enhance heat transfer. Bio-crudes with average yields of 26 wt%, 33 wt% and 25 wt% were produced from Miscanthus, Spirulina and sewage sludge, respectively. The yields also appeared to increase with reactor run time. Bio-crude from HTL of Spirulina was mainly composed of palmitic acid, glycerol, heptadecane and linolelaidic acid, while biocrude from sewage sludge contained mainly palmitic acid, oleic acid and stearic acid. In contrast, biocrude from HTL of Miscanthus consisted of a large number of different phenolics. An energetic comparison between the three feedstocks revealed a thermal efficiency of 47%, 47% and 33% and energy return on investment (EROI) of 2.8, 3.3 and 0.5 for HTL of Miscanthus, Spirulina and sewage sludge, respectively.

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“…The reaction time mostly ranged from 15-60 minutes, except some fast HTL that was conducted in less than 5 minutes [10,30]. In the past five years, different feedstocks were tested under continuous HTL but the majority were algae ( [41]. Table 2 shows that most of the continuous HTL reactors used were operated in plug flow The biocrude oil products were proven to be suitable for powering transportation machinery after modest refinement (below 100 °C) [2,22].…”

Section: Continuous/pilot Development For Htlmentioning

confidence: 99%

A perspective on hydrothermal processing of sewage sludge

Chen

Haque

et al. 2020

Current Opinion in Environmental Science & Health

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The US annually produces 79 million dry tons of liquid organic waste including sewage sludge.Anaerobic digestion can only reduce the sludge volume by 50% in mass, leaving the other half as a growing waste management and hygienic problem. Hydrothermal Processing (HTP), a set of several chemical digestion processes, could be employed to convert sewage sludge into valuable products and minimize potential environmental pollution risks. Specifically, hydrothermal carbonization and hydrothermal liquefaction have been extensively studied to sustainably manage sludge. Two of the main reasons for this are the high upscaleability of HTP for public waste management and that it is estimated that HTP can recover eleven times more energy from waste products than landfilling. An integration of HTP with anaerobic digestion or recycling the soluble organics (in the HTP aqueous products) into the HTP process could lead to a higher overall rate of energy recovery for municipal sewage sludge.

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Conversion of a wet waste feedstock to biocrude by hydrothermal processing in a continuous-flow reactor: grape pomace

Cited by 37 publications

References 25 publications

Continuous Hydrothermal Liquefaction of Biomass: A Critical Review

Continuous Hydrothermal Liquefaction of Biomass: A Critical Review

Continuous Hydrothermal Liquefaction of Biomass in a Novel Pilot Plant with Heat Recovery and Hydraulic Oscillation

A perspective on hydrothermal processing of sewage sludge

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