scholarly journals Hydrochar: A Review on Its Production Technologies and Applications

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 939
Author(s):  
Shima Masoumi ◽  
Venu Babu Borugadda ◽  
Sonil Nanda ◽  
Ajay K. Dalai

Recently, due to the escalating usage of non-renewable fossil fuels such as coal, natural gas and petroleum coke in electricity and power generation, and associated issues with pollution and global warming, more attention is being paid to finding alternative renewable fuel sources. Thermochemical and hydrothermal conversion processes have been used to produce biochar and hydrochar, respectively, from waste renewable biomass. Char produced from the thermochemical and hydrothermal decomposition of biomass is considered an environmentally friendly replacement for solid hydrocarbon materials such as coal and petroleum coke. Unlike thermochemically derived biochar, hydrochar has received little attention due to the lack of literature on its production technologies, physicochemical characterization, and applications. This review paper aims to fulfill these objectives and fill the knowledge gaps in the literature relating to hydrochar. Therefore, this review discusses the most recent studies on hydrochar characteristics, reaction mechanisms for char production technology such as hydrothermal carbonization, as well as hydrochar activation and functionalization. In addition, the applications of hydrochar, mainly in the fields of agriculture, pollutant adsorption, catalyst support, bioenergy, carbon sequestration, and electrochemistry are reviewed. With advancements in hydrothermal technologies and other environmentally friendly conversion technologies, hydrochar appears to be an appealing bioresource for a wide variety of energy, environmental, industrial, and commercial applications.

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Christos M. Kalamaras ◽  
Angelos M. Efstathiou

Hydrogen (H2) is currently used mainly in the chemical industry for the production of ammonia and methanol. Nevertheless, in the near future, hydrogen is expected to become a significant fuel that will largely contribute to the quality of atmospheric air. Hydrogen as a chemical element (H) is the most widespread one on the earth and as molecular dihydrogen (H2) can be obtained from a number of sources both renewable and nonrenewable by various processes. Hydrogen global production has so far been dominated by fossil fuels, with the most significant contemporary technologies being the steam reforming of hydrocarbons (e.g., natural gas). Pure hydrogen is also produced by electrolysis of water, an energy demanding process. This work reviews the current technologies used for hydrogen (H2) production from both fossil and renewable biomass resources, including reforming (steam, partial oxidation, autothermal, plasma, and aqueous phase) and pyrolysis. In addition, other methods for generating hydrogen (e.g., electrolysis of water) and purification methods, such as desulfurization and water-gas shift reactions are discussed.


2021 ◽  
Vol 3 (1) ◽  
pp. 243-259
Author(s):  
Yadhu N. Guragain ◽  
Praveen V. Vadlani

Lignocellulosic biomass feedstocks are promising alternatives to fossil fuels for meeting raw material needs of processing industries and helping transit from a linear to a circular economy and thereby meet the global sustainability criteria. The sugar platform route in the biochemical conversion process is one of the promising and extensively studied methods, which consists of four major conversion steps: pretreatment, hydrolysis, fermentation, and product purification. Each of these conversion steps has multiple challenges. Among them, the challenges associated with the pretreatment are the most significant for the overall process because this is the most expensive step in the sugar platform route and it significantly affects the efficiency of all subsequent steps on the sustainable valorization of each biomass component. However, the development of a universal pretreatment method to cater to all types of feedstock is nearly impossible due to the substantial variations in compositions and structures of biopolymers among these feedstocks. In this review, we have discussed some promising pretreatment methods, their processing and chemicals requirements, and the effect of biomass composition on deconstruction efficiencies. In addition, the global biomass resources availability and process intensification ideas for the lignocellulosic-based chemical industry have been discussed from a circularity and sustainability standpoint.


2021 ◽  
Vol 13 (12) ◽  
pp. 6797
Author(s):  
Peter Mako ◽  
Andrej Dávid ◽  
Patrik Böhm ◽  
Sorin Savu

Sustainability of transport systems is a key issue in transport. The main question is whether high levels of road and railway transport in areas along navigable waterways is an effective solution for this issue. The Danube waterway is an example. Generally, it is not observed that traffic performance is not as high as on the Rhine. This paper deals with the revelation of the available capacity of this waterway based on approximation functions and their comparison with real transport performances. This methodology points to the level of use of waterways. The connection of this model with the production of fossil fuels creates a basis for a case study. The case study in this paper offers a possibility for a sustainable and environmentally friendly transition from road transport to inland water transport on the example of specific transport routes. The main contribution of this paper is a presentation of the application of sustainable models of use transport capacity to increase the share of environmentally friendly and sustainable inland water transport. The conclusion based on the case study and materials is that the available capacity of inland water transport on the Danube could support the transition of traffic performances to sustainable and environmentally friendly means of transport.


2021 ◽  
Vol 13 (2) ◽  
pp. 788
Author(s):  
Zulqarnain ◽  
Muhammad Ayoub ◽  
Mohd Hizami Mohd Yusoff ◽  
Muhammad Hamza Nazir ◽  
Imtisal Zahid ◽  
...  

Dependence on fossil fuels for meeting the growing energy demand is damaging the world’s environment. There is a dire need to look for alternative fuels that are less potent to greenhouse gas emissions. Biofuels offer several advantages with less harmful effects on the environment. Biodiesel is synthesized from the organic wastes produced extensively like edible, non-edible, microbial, and waste oils. This study reviews the feasibility of the state-of-the-art feedstocks for sustainable biodiesel synthesis such as availability, and capacity to cover a significant proportion of fossil fuels. Biodiesel synthesized from oil crops, vegetable oils, and animal fats are the potential renewable carbon-neutral substitute to petroleum fuels. This study concludes that waste oils with higher oil content including waste cooking oil, waste palm oil, and algal oil are the most favorable feedstocks. The comparison of biodiesel production and parametric analysis is done critically, which is necessary to come up with the most appropriate feedstock for biodiesel synthesis. Since the critical comparison of feedstocks along with oil extraction and biodiesel production technologies has never been done before, this will help to direct future researchers to use more sustainable feedstocks for biodiesel synthesis. This study concluded that the use of third-generation feedstocks (wastes) is the most appropriate way for sustainable biodiesel production. The use of innovative costless oil extraction technologies including supercritical and microwave-assisted transesterification method is recommended for oil extraction.


Author(s):  
Shruti Mohapatra ◽  
Raj Kishore Mishra ◽  
Khitish K. Sarangi

Environmentally sustainable energy sources are called for due to contemporaneous development in industries along with the rapid pace of urbanization. Ethanol produced from biomass can be deliberated as a clean and safest liquid fuel and an alternative to fossil fuels as they have provided unique environmental, strategic economic benefits. For the past decade, it has been noticed that there is an increasing trend found in bio ethanol production which has created a stimulus to go for advancement in bio ethanol production technologies. Several feed stocks have been used for the bio ethanol production but the second generation bio ethanol has concentrated on the lignocellulosic biomass. Plenteous lignocellulosic biomass in the world can be tapped for ethanol production, but it will require significant advances in the ethanol production process from lignocellulosic because of some technical and economic hurdles found in commercial scale. This review will encompass the current status of bio ethanol production in terms of their economic and environmental viability along with some research gaps as well as policy implications for the same.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Huang Huanhai

The potential crisis of energy and the deterioration of ecological environment make the world's cumbersomedevelopment of renewable energy including new energy, including solar energy. Traditional energy in the coal, oil andnatural gas are evolved from ancient fossils, it is collectively referred to as fossil fuels. As the world's energy needscontinue to increase, fossil fuels will also be depleted, it is necessary to fi nd a new energy to replace the traditionalenergy. Solar energy is a clean renewable energy with mineral energy incomparable superiority. Modern society shouldbe a conservation-oriented society, and social life should also be a life-saving energy. At the same time, Premier WenJiabao also proposed on June 30, 2005 and stressed the need to speed up the construction of a conservation-orientedsociety. And solar energy as an inexhaustible new environmentally friendly energy has become the world's energyresearch work in the world an important issue. Is the world in the economic situation to take a simpler, economical,environmentally friendly and reliable building heating and heating energy-saving measures. This paper summarizes thecurrent global energy status, indicating the importance of solar power and prospects. Details of the various solar powergeneration methods and their advantages, and made a comparison of this power generation parameters. At the sametime pointed out that the diffi culties faced by solar power and solutions, as well as China's solar power of the favorableconditions and diffi culties. The future of China's solar energy made a prospect.


2013 ◽  
Vol 726-731 ◽  
pp. 634-637 ◽  
Author(s):  
Yan Qiu Lei ◽  
Hai Quan Su

A green and sustainable route for preparation of hydrochars from cornstalk by hydrothermal carbonization (200°C) was described. The morphology of the hydrochars changed with reaction time increased, the surface of the materials contained a large number of functional groups, showed higher adsorption capacity for Cr (VI) than activated carbon and the removal rates of Cr (VI) were 67% and 29% respectively (pH=1, 20°C).


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3541
Author(s):  
Jerzy Korol ◽  
Aleksander Hejna ◽  
Dorota Burchart-Korol ◽  
Jan Wachowicz

Composites containing natural fibers are considered environmentally friendly materials which is related to the reduced use of fossil fuels and the emission of carbon dioxide compared to petroleum-based polymers. Nevertheless, a complete evaluation of their environmental impact requires a broader view. This paper presents a carbon, ecological, and water footprints assessment of polypropylene-based composites filled with cotton, jute, and kenaf fibers based on a standardized European pallet (EUR-pallet) case study. Obtained results were compared with unmodified polypropylene and composite with glass fibers. Incorporation of 30 wt% of cotton, jute, and kenaf fibers into a polypropylene matrix reduced its carbon footprint by 3%, 18%, and 18%, respectively. Regarding the ecological footprint, an 8.2% and 9.4% reduction for jute and kenaf fibers were noted, while for cotton fibers, its value increased by 52%. For these footprints, the use of jute and kenaf fibers was more beneficial than glass fibers. Nevertheless, the application of natural fibers caused a 286%, 758%, and 891% drastic increase of water footprint of the final product, which was mainly affected by cultivation and irrigation of crops. Therefore, in a holistic view, the incorporation of natural fibers into the polypropylene matrix definitely cannot be impartially considered as an environmentally friendly solution.


2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Emad Rokni ◽  
Yu Liu ◽  
Xiaohan Ren ◽  
Yiannis A. Levendis

Combustion-generated emissions of acid gases, such as nitrogen-bearing species, constitute environmental pollutants and some are subjected to environmental regulations. Assessment of such emissions is important to decide what systems need to be put in place for their control. This applies to both conventional fossil fuels and for alternative environmentally friendlier fuels, such as renewable biomass. This research investigated the emissions of nitrogen-bearing gases, which evolve from combustion of biomass (corn straw) in a fixed bed furnace, as a function of specific air flowrate (m˙air) through the bed and of moisture content of the fuel. The effect of torrefaction of corn straw on the combustion-generated nitrogen bearing emissions was also examined. The predominant nitrogen-bearing species in the combustion effluents were hydrogen cyanide (HCN), nitrogen oxide (NO), and ammonia (NH3). Increasing m˙air through the bed, to enhance the combustion rate, increased the emissions of HCN, NO, and NH3. As the m˙air through the bed increased by a factor of 5, the amounts of HCN, NO, and NH3 gases increased by factors of 3–4. As the moisture content of the biomass was reduced by drying, the combustion-generated emissions of NO increased mildly, whereas those of both NH3 and HCN decreased. Furthermore, the combustion-generated emissions of NO and NH3 from torrefied biomass were found to be higher than those from raw biomass. In contrast, the combustion-generated emissions of HCN from torrefied biomass were found to be lower than those generated from raw biomass.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5383
Author(s):  
Hafiz Muhammad Uzair Ayub ◽  
Sang Jin Park ◽  
Michael Binns

To help meet the global demand for energy and reduce the use of fossil fuels, alternatives such as the production of syngas from renewable biomass can be considered. This conversion of biomass to syngas is possible through a thermochemical gasification process. To design such gasification systems, model equations can be formulated and solved to predict the quantity and quality of the syngas produced with different operating conditions (temperature, the flow rate of an oxidizing agent, etc.) and with different types of biomass (wood, grass, seeds, food waste, etc.). For the comparison of multiple different types of biomass and optimization to find optimal conditions, simpler models are preferred which can be solved very quickly using modern desktop computers. In this study, a number of different stoichiometric thermodynamic models are compared to determine which are the most appropriate. To correct some of the errors associated with thermodynamic models, correction factors are utilized to modify the equilibrium constants of the methanation and water gas shift reactions, which allows them to better predict the real output composition of the gasification reactors. A number of different models can be obtained using different correction factors, model parameters, and assumptions, and these models are compared and validated against experimental data and modelling studies from the literature.


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