scholarly journals Biocrude Production from Hydrothermal Liquefaction of Chlorella: Thermodynamic Modelling and Reactor Design

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6602
Author(s):  
Lili Qian ◽  
Jun Ni ◽  
Zhiyang Xu ◽  
Bin Yu ◽  
Shuang Wang ◽  
...  

Hydrothermal liquefaction can directly and efficiently convert wet biomass into biocrude with a high heating value. We developed a continuous hydrothermal liquefaction model via Aspen Plus to explore the effects of moisture content of Chlorella, reaction pressure and temperature on thermodynamic equilibrium yields, and energy recoveries of biocrude. We also compared the simulated biocrude yield and energy recoveries with experiment values in literature. Furthermore, vertical and horizontal transportation characteristics of insoluble solids in Chlorella were analyzed to determine the critical diameters that could avoid the plugging of the reactor at different flow rates. The results showed that the optimum moisture content, reaction pressure, and reaction temperature were 70–90 wt%, 20 MPa, and 250–350 °C, respectively. At a thermodynamic equilibrium state, the yield and the energy recovery of biocrude could be higher than 56 wt% and 96%, respectively. When the capacity of the hydrothermal liquefaction system changed from 100 to 1000 kg·h−1, the critical diameter of the reactor increased from 9 to 25 mm.

FLORESTA ◽  
2015 ◽  
Vol 45 (4) ◽  
pp. 713 ◽  
Author(s):  
Diego Aleixo Silva ◽  
Gabriela Tami Nakashima ◽  
João Lúcio Barros ◽  
Alessandra Luzia Da Roz ◽  
Fabio Minoru Yamaji

O objetivo deste trabalho foi caracterizar a produção de briquetes feita a partir de quatro diferentes biomassas residuais. Foram utilizados os resíduos de serragem de Eucalyptus sp, serragem de Pinus sp, bagaço de cana-de-açúcar (Saccharum officinarum L.) e palha de cana-de-açúcar. Os resíduos foram tratados para que obtivessem 12% de umidade e uma granulometria inferior a 1,70 mm. Foram produzidos 15 briquetes para cada um dos quatro tratamentos. A pressão utilizada foi de 1250 kgf.cm-2 durante 30 segundos. Os briquetes obtiveram densidades que oscilaram 0,88 a 1,11 g.cm-3. Isto representou uma faixa de 5 a 14 vezes a menos de ocupação de volume para uma mesma quantidade de massa. O poder calorifico foi de 19.180 J.kg-1 e 20.315 J.kg-1 para as serragens de eucalipto e pinus respectivamente. Para o bagaço e palha de cana os valores foram de 18.541 J.kg-1 e 15.628 J.kg-1. A palha da cana-de-açúcar apresentou um teor de cinzas de 12%. As expansões dos tratamentos oscilaram 4 a 9% e as resistências mecânicas variaram de 1,215 MPa à 0,270 MPa. Todos os briquetes se mostraram resistentes para um empilhamento superior a 10 m de altura. O procedimento adotado pode ajudar a diminuir o espaço de estocagem e de transporte. AbstractThis research aims to characterize the production of briquettes from four different biomasses. We used residues such as Eucalyptus sp sawdust, Pinus sp sawdust , sugarcane bagasse (Saccharum officinarum L.) and sugarcane straw. The residues were treated to obtain 12% moisture content and particle size less than 1.70 mm. We produced 15 briquettes for each treatment. The pressure used was 1250 kgf.cm-2 for 30 seconds. The briquettes obtained densities ranged from 0.88 to 1.11 g.cm-3. This represented a range of 5 to 14 times less volume occupancy for the same amount of mass. The high heating value (HHV) was 19,180 J.kg-1 and 20,315 J.kg-1 for eucalyptus and pine sawdust respectively. The HHV for the bagasse was 18,541 J.kg-1 and for straw was 15,628 J.kg-1. The straw presented an ash content of 12%. The expansions of the treatments ranged 4 to 9% and mechanical resistances ranging from 1,215 MPa to 0,270 MPa. All briquettes were resistant to a higher stacking to 10 m high. The methods can help to decrease the space of storage and transport.Keywords: Waste; biofuel; energy; compression; stacking.


2021 ◽  
Vol 882 (1) ◽  
pp. 012029
Author(s):  
M A Rahmanta

Abstract The Coal Water Slurry (CWS) technology increases the calorific value and changes the phase of coal from solid to liquid. The CWS Plant with a coal capacity of 1.4 t/hour located at Karawang, West Java converts lignite coal to CWS. Coal undergoes pulverizing, upgrading, and slurry-making processes to become CWS. Pulverization is the process of refining coal size into 200 mesh. The upgrading process is through reducing the moisture content in heat exchangers (HE). It occurs in HE where the coal is pressurized to 15 MPa and the temperature is maintained at 330 0C for 30 minutes. The research objective was to determine the CWS characteristics of the South Sumatra Pendopo lignite coal. The method used is through testing where the Pendopo coal is converted into CWS at the CWS Plant. The result shows that Pendopo coal which has a heating value of High Heating Value (HHV) 2,725.00 kCal/kg As Received (AR) has an increase in HHV heating value of 3,218.00 kcal/kg AR when it becomes CWS. The total moisture content of Pendopo coal has decreased from 49.36% to 44.58% when it becomes CWS. The fixed carbon content of Pendopo coal increased from 19.78% AR to 24.01% AR.


2019 ◽  
Vol 693 (1) ◽  
pp. 7-17
Author(s):  
Krissina Camilla Molinari ◽  
Washington Luiz Esteves Magalhães ◽  
Agnieszka Pawlicka ◽  
Gilmara de Oliveira Machado

2019 ◽  
Vol 2 (3) ◽  
pp. 954-963
Author(s):  
Aboubaker AbdallaIbrahim Ali ◽  
Hüseyin Akilli

Dewatered domestic wastewater sludge (DDWS) is one of the largest contributors of waste material in the world, and it immediately elevates local environmental problems, especially in the urban area. The conversion of this material into a usable form of green energy, such as syngas through gasification, can be a vital solution. Hence, this method not only solves the environmental issues related to DDWS disposal but also participates as an energy source. To achieve this goal, the essential fuel characterization, which includes initial moisture content, high heating value, ultimate analysis, and proximate analysis, were carried out to assess the potential energy in DDWS. Due to the high expenses of the successful design of the gasifier reactor, and there are no efficient methods to predict the gasification performance, the model of the DDWS gasification process using ASPEN Plus software was developed. As ASPEN Plus software does not contain a built-in gasifier reactor model, a combination of various reactors is used to simulate the gasification processes. These processes were divided out into two stages. In the first stage, DDWS was decomposed into its element by specifying yield distribution. By using Gibbs free energy minimization approach, the gasification reactions were modeled. The current model was validated with the previously published work. From the characterization findings, DDWS showed high initial moisture content 84.64% and potential energy with 16.84 MJ/kg high heating value. The proximate analysis based on the dry base of DDWS exhibited that more than 55.42 % of their mass is composed of volatile materials, and ash content is found to be less than 25.79%.


2021 ◽  
Vol 13 (15) ◽  
pp. 8147
Author(s):  
Sasiwimol Khawkomol ◽  
Rattikan Neamchan ◽  
Thunchanok Thongsamer ◽  
Soydoa Vinitnantharat ◽  
Boonma Panpradit ◽  
...  

A horizontal drum kiln is a traditional method widely used in Southeast Asian countries for producing biochar. An understanding of temperature conditions in the kiln and its influence on biochar properties is crucial for identifying suitable biochar applications. In this study, four agricultural residues (corncob, coconut husk, coconut shell, and rice straw) were used for drum kiln biochar production. The agricultural residues were turned into biochar within 100–200 min, depending on their structures. The suitability of biochar for briquette fuels was analyzed using proximate, ultimate, and elemental analysis. The biochar’s physical and chemical properties were characterized via bulk density, iodine number, pHpzc, SEM, and FTIR measurements. All biochars had low O/C and H/C ratios and negative charge from both carbonyl and hydroxyl groups. Coconut husk and shell biochar had desirable properties such as high heating value and a high amount of surface functional groups which can interact with nutrients in soil. These biochars are thus suitable for use for a variety of purposes including as biofuels, adsorbents, and as soil amendments.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4492
Author(s):  
Komeil Kohansal ◽  
Kamaldeep Sharma ◽  
Saqib Sohail Toor ◽  
Eliana Lozano Sanchez ◽  
Joscha Zimmermann ◽  
...  

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.


2020 ◽  
Vol 6 (2) ◽  
pp. 43 ◽  
Author(s):  
Rubén González ◽  
Judith González ◽  
José G. Rosas ◽  
Richard Smith ◽  
Xiomar Gómez

Anaerobic digestion is an established technological option for the treatment of agricultural residues and livestock wastes beneficially producing renewable energy and digestate as biofertilizer. This technology also has significant potential for becoming an essential component of biorefineries for valorizing lignocellulosic biomass due to its great versatility in assimilating a wide spectrum of carbonaceous materials. The integration of anaerobic digestion and pyrolysis of its digestates for enhanced waste treatment was studied. A theoretical analysis was performed for three scenarios based on the thermal needs of the process: The treatment of swine manure (scenario 1), co-digestion with crop wastes (scenario 2), and addition of residual glycerine (scenario 3). The selected plant design basis was to produce biochar and electricity via combined heat and power units. For electricity production, the best performing scenario was scenario 3 (producing three times more electricity than scenario 1), with scenario 2 resulting in the highest production of biochar (double the biochar production and 1.7 times more electricity than scenario 1), but being highly penalized by the great thermal demand associated with digestate dewatering. Sensitivity analysis was performed using a central composite design, predominantly to evaluate the bio-oil yield and its high heating value, as well as digestate dewatering. Results demonstrated the effect of these parameters on electricity production and on the global thermal demand of the plant. The main significant factor was the solid content attained in the dewatering process, which excessively penalized the global process for values lower than 25% TS.


2018 ◽  
Vol 37 (1) ◽  
pp. 544-557 ◽  
Author(s):  
Alejandra Saffe ◽  
Anabel Fernandez ◽  
Germán Mazza ◽  
Rosa Rodriguez

The use of energy from biomass is becoming more common worldwide. This energy source has several benefits that promote its acceptance; it is bio-renewable, non-toxic and biodegradable. To predict its behavior as a fuel during thermal treatment, its characterization is necessary. The experimental determination of ultimate analysis data requires special instrumentation, while proximate analysis data can be obtained easily by using common equipment but, the required time is high. In this work, a methodology is applied based on thermogravimetric analysis, curves deconvolution and empirical correlations for characterizing different regional agro-industrial wastes to determine the high heating value, the contents of moisture, volatiles matter, fixed carbon, ash, carbon, hydrogen, oxygen, lignin, cellulose and hemicellulose. The obtained results are similar to those using standard techniques, showing the accuracy of proposed method and its wide application range. This methodology allows to determine the main parameters required for industrial operation in only in one step, saving time.


Author(s):  
V. Dhivakhar ◽  
Maju Varghese ◽  
Keerthi M. S. ◽  
S. Kaviya

About 40% of the Global Electricity produced is fuelled by coal. Although Coal has various advantages like good High Heating Value, easy availability etc., it also has various disadvantages. Green House Gas Released from Coal Thermal Power Plants is the single major contributor to Global warming. Coal is also nonrenewable. Hence it is important to analyze the viability of potential alternatives and reduce the usage of coal. In this assessment, various potential replacements of coal have been analyzed based on their High heating value (HHV) and their Global Warming Potential. The Global warming Potential (GWP) of the assessed fuels have been calculated by the Respiratory Quotient (RQ) Factor method. Hence a direct comparison between Coal and other replacements based on their HHV and GWP has been performed.


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