Hydrothermal Carbonization Of Biomass Research Articles

Hydrothermal Carbonization of Green Harvesting Residues (GHRs) from Sugar Cane: Effect of Temperature and Water/GHR Ratio on Mass and Energy Yield.

The Valle del Cauca region in Colombia is a significant producer of sugar cane, resulting in large quantities of agricultural residues (green harvesting residues (GHRs)). To ensure sustainable management of these residues, it is crucial to implement proper treatment and disposal technologies while also reusing waste to produce biogas, bioelectricity, or biofuels. The biomass hydrothermal carbonization process offers a means to convert these residues into useful products that serve as fuels or valuable energy materials. This thermal treatment involves the use of water as a solvent and reagent within the biomass's internal structure. In this study, sugar cane cutting residues were collected with relatively high moisture content of 8.5% wt. These residues were subjected to carbonization temperatures ranging from 200 to 300 °C, along with water/GHR ratios between 5/1 and 10/1. The properties of the resulting hydrocarbons were analyzed by using proximate and ultimate analysis. The objective was to produce hydrochar samples with the highest higher heating value (HHV) and energy density compared with the GHRs. The HHV value of the hydrochar showed a significant increase of 69.6% compared with that of the GHRs, reaching 43.5 MJ/kg. Besides, process parameters were optimized for mass yields, energy yields, and ash content. This exploration led us to investigate a new temperature range between 280 and 320 °C, allowing us to establish an optimal value for the hydrochar's properties.

Biomass hydrothermal carbonization solution-assisted synthesis of intercalation-expanded core–shell structured molybdenum disulfide for efficient adsorption of Cr (VI) in electroplating wastewater treatment

Cr (VI) is a common heavy metal pollutant in electroplating wastewater. This study introduces the liquid-phase product from the hydrothermal reaction of coffee grounds (CGHCL) into the synthesis process of molybdenum disulfide, assisting in the fabrication of an intercalated, expanded core–shell structured molybdenum disulfide adsorbent (C-MoS2), designed for the adsorption and reduction of Cr (VI) from electroplating wastewater. The addition of CGHCL significantly enhances the adsorption performance of MoS2. Furthermore, C-MoS2 exhibits exceedingly high removal efficiency and excellent regenerative capability for Cr (VI)-containing electroplating wastewater. The core–shell structure effectively minimizes molybdenum leaching to the greatest extent, while the oleophobic interface is unaffected by oily substances in water, and the expanded interlayer structure ensures the long-term stability of C-MoS2 in air (90 days). This study provides a viable pathway for the resource utilization of biomass and the application of molybdenum disulfide-based materials in wastewater treatment.

A novel intelligent system based on machine learning for hydrochar multi-target prediction from the hydrothermal carbonization of biomass

Hydrothermal carbonization (HTC) is a thermochemical conversion technology to produce hydrochar from wet biomass without drying, but it is time-consuming and expensive to experimentally determine the optimal HTC operational conditions of specific biomass to produce desired hydrochar. Therefore, a machine learning (ML) approach was used to predict and optimize hydrochar properties. Specifically, biochemical components (proteins, lipids, and carbohydrates) of biomass were predicted and analyzed first via elementary composition. Then, accurate single-biomass (no mixture) based ML multi-target models (average R2 = 0.93 and RMSE = 2.36) were built to predict and optimize the hydrochar properties (yield, elemental composition, elemental atomic ratio, and higher heating value). Biomass composition (elemental and biochemical), proximate analyses, and HTC conditions were inputs herein. Interpretation of the model results showed that ash, temperature, and the N and C content of biomass were the most critical factors affecting the hydrochar properties, and that the relative importance of biochemical composition (25%) for the hydrochar was higher than that of operating conditions (19%). Finally, an intelligent system was constructed based on a multi-target model, verified by applying it to predict the atomic ratios (N/C, O/C, and H/C). It could also be extended to optimize hydrochar production from the HTC of single-biomass samples with experimental validation and to predict hydrochar from the co-HTC of mixed biomass samples reported in the literature. This study advances the field by integrating predictive modeling, intelligent systems, and mechanistic insights, offering a holistic approach to the precise control and optimization of hydrochar production through HTC.Graphical

Cross-upgrading of biomass hydrothermal carbonization and pyrolysis for high quality blast furnace injection fuel production: Physicochemical characteristics and gasification kinetics analysis

Cross-upgrading of biomass hydrothermal carbonization and pyrolysis for high quality blast furnace injection fuel production: Physicochemical characteristics and gasification kinetics analysis

Synthetic natural gas production using CO2-rich waste stream from hydrothermal carbonization of biomass: Effect of impurities on the catalytic activity

The utilization of biomass and bio-waste, particularly through hydrothermal processes, has shown promise as a technology for converting these materials into valuable products. While most research has traditionally focused on the solid and liquid byproducts of these hydrothermal treatments, the gaseous phase has often been overlooked. This study specifically investigates the conversion of off-gases produced during hydrothermal carbonation (HTC) into synthetic natural gas, offering a readily marketable product with economic potential. Although the methanation of conventional flue gases has been extensively studied, dealing with non-standard off-gases from processes like HTC presents challenges due to the presence of minor impurities like CO and CH4. This novel research seeks to experimentally evaluate the methanation of HTC off-gases using nickel-based catalysts and analyze how these impurities affect the catalytic performance. The studied catalysts include nickel supported by ceria and alumina, as well as alumina supported nickel-cobalt systems. The results demonstrate that these catalysts exhibit high CO2 conversion and CH4 selectivity under ideal gas conditions. However, when real gas compositions with impurities are considered, CO2 conversion decreases at lower temperatures (ca. 20% lower conversion for real gas vs. ideal), probably due to side reactions such as CH4 cracking. This difference becomes less pronounced at higher temperatures. Nevertheless, the catalysts perform satisfactorily, especially at temperatures exceeding 350 °C. In conclusion, this study sheds light on the methanation of HTC off-gases and underscores the significance of understanding how impurities in real gases impact the process, providing potential directions for future research.

Machine-learning-aided hydrochar production through hydrothermal carbonization of biomass by engineering operating parameters and/or biomass mixture recipes

Hydrochar serves not only as a fuel source but also as a versatile carbon material that has found extensive application across various domains. The application performance of hydrochar, e.g., energy recovery and carbon stability, is substantially influenced by its mass yield, higher heating value (HHV), and compositions (C, H, O, N, S, and ash), so the prediction and engineering of these properties is promising. In this study, two machine learning algorithms, namely gradient boosting regression (GBR) and random forest (RF), were used to predict the hydrochar properties mentioned above. The GBR models (with test regression coefficient (R2) values of 0.87–0.98 for single-target prediction and average test R2 of 0.93 for multi-target prediction) exhibited superior predictive capabilities to the RF models (with test R2 of 0.78–0.97 for single-target and average test R2 of 0.90 for multi-target prediction). The interpretation of ML models revealed the importance ranking of features for all targets. Then, engineering hydrochar was carried out through three different optimizations to the as-built multi-target prediction model: i) optimizations of HTC conditions for given biomass samples; ii) optimization of biomass mixture recipes; iii) simultaneous optimization of both biomass mixing recipes and HTC conditions.

Fate of biomass inorganic elements during hydrothermal carbonization: an experimental study on agro-food waste

AbstractThe distribution of inorganic elements between solid and liquid phases during biomass hydrothermal carbonization (HTC) is a poorly investigated topic despite its importance for process optimization. To fill in this gap, the distribution of inorganic elements and their forms were determined for three agro-food waste feedstocks converted at HTC temperatures of 180, 220, and 260 °C in 12 h. Satisfactory balances were achieved, with values between 80 and 92% for C and N, and 80 and 110% for most inorganic elements. At 180 °C, over 90% of P, Mg, Ca, K, Na, and Mn were removed from hydrochars whatever feedstock. At higher temperatures, P, Mg, Ca, and Mn were partly reincorporated into hydrochars (between 7 and 53%), possibly due to the formation of insoluble precipitates, while K and Na remained in the liquid. On the opposite, some minor elements, Cu and Al, remained in the hydrochars, whatever temperature. Si showed different removal behaviors according to feedstock and temperature. These results show the possibility of optimizing the removal of inorganic elements from hydrochars using different temperatures.

Application of catalysts in biomass hydrothermal carbonization for the preparation of high-quality blast furnace injection fuel

The low energy density of biomass is a crucial limitation for their application in the steel industry. This study used catalyst-catalysed hydrothermal carbonization (HTC) to prepare higher-quality hydrochar from biomass. The effects of acid-base homogeneous catalysts (Fe(NO3)3·9H2O and CaO), liquid phase product (circulating water) and carbonization temperatures on the physicochemical properties and microscopic morphology of hydrochars were investigated. The results showed that higher carbonization temperature, circulating water and Fe(NO3)3·9H2O all raised the higher heating value (HHV) of hydrochar. When 4% of Fe(NO3)3·9H2O was added, the HHV of hydrochar reached 30.05 MJ/kg, which was 1.15 times higher than without catalysts. The above three conditions can also make the ordering degree in the carbonaceous structure lower ordered and enhance the reaction performance of the hydrochar. Meanwhile, the addition of Fe(NO3)3·9H2O at 240 °C can reduce the hydrochar ignition and burnout temperatures and enhance the combustion performance. Moreover, it was demonstrated that circulating water promoted the HTC more than deionized water. In conclusion, adding Fe(NO3)3·9H2O or circulating water to the HTC process can produce higher-quality hydrochar.

Removal of oxygen-containing functional groups during hydrothermal carbonization of biomass: Experimental and DFT study

Removal of oxygen-containing functional groups during hydrothermal carbonization of biomass: Experimental and DFT study

Parameter study in preparation of nitrogen-rich-activated carbon for supercapacitors' application using multilevel factorial design

This research aims to study the effect of process parameters on hydrochar modification from biomass on physical and electrochemical properties. Hydrochar is produced by hydrothermal carbonization of biomass at 275 °C for 2 h using an activating agent of CaCl2. Hydrochar was modified by impregnation at a time variation (1 and 2 h) and doping type (urea, thiourea, and ammonium persulfate). The ratio of hydrochar to doping compound (1:1, 1:2, and 1:3). Activation is carried out by pyrolysis at 800 °C by flowing N2 and CO2 gases. The doping ratio and impregnation time significantly increase the yield of ​​activated carbon. The highest value is 39.97 percent for the sample with thiourea and a ratio doping of 1:3 at 2 h (ACT13-2). The main process parameter and the interaction of impregnation time with the doping type affect the surface area of ​​activated carbon. Porosity analysis indicates the product had a mesoporous structure with the largest surface area of ​​677.44 m2 g−1 for the sample with ammonium persulfate and a ratio of 1:1 at 2 h (ACA11-2). The process parameters significantly reduce electrolyte and charge transfer resistance and increase the specific capacitance. The cyclic voltammetry analysis shows the highest capacitance of the supercapacitor cell of 43.25F g−1 was obtained for the sample with urea and a ratio of 1:3 at 2 h (ACU13-2). The endurance test was carried out for 5000 cycles and showed that the supercapacitor cells were stable at 98 percent. Research findings indicate that the hydrochar impregnation method followed by activation can be an effective alternative to produce inexpensive nitrogen-rich activated carbon for supercapacitor applications.

Green coal substitutes for boilers through hydrothermal carbonization of biomass: pyrolysis and combustion behavior

Hydrothermal carbonization (HTC) is a thermochemical conversion process in aqueous phase that is well suited for the valorization of waste biomass. The carbonaceous solid phase produced by the HTC process (the so-called hydrochar) shows interesting properties that make it similar to conventional solid fuels. Thus, it may be used in existing coal-handling infrastructures, rendering it particularly attractive for co-firing. Two different biomasses are investigated: walnut shells as biomass richer in lignin, and miscanthus as biomass richer in hemicellulose/cellulose. The properties of the resulting hydrochars are analyzed and compared with those of untreated biomass and of coals typically used in industrial boilers. The HTC treatment results in the reduction of the cellulose/hemicellulose contribution and O/C ratio, and in an increase of aromatic structures, heating value and grindability. The behavior of the hydrochars upon pyrolysis under fast heating conditions typical of pulverized fuel boilers is investigated using a heated strip reactor (HSR). The combustion reactivity tests in a thermogravimetric apparatus show that the HTC treatment levels off the differences between various biomasses, while the HSR treatment generates chars with the same combustion reactivity as char obtained from coal erasing the differences between HTC-derived biomass and fossil fuels. As for char reactivity, the HTC process reduces the impact of the different biomass compositions on tar formation, but few differences are still observed regarding the volatile phase between biomass hydrochar and coal samples. Results are analyzed and discussed with the goal of evaluating the potential of HTC of lignocellulosic biomass to generate green fuels suitable for industrial boilers.

Density functional theory simulation of heterogeneous polymerization reactions during biomass hydrothermal carbonization

AbstractCarbonaceous microspheres formed through heterogeneous polymerization reactions during hydrothermal carbonization of biomass showed a considerable effect on the mass yield and physicochemical properties of hydrochar. In exploring the growth mechanism of carbonaceous microspheres, the heterogeneous polymerization reaction of four typical organic components (5‐hydroxymethylfurfural, furfural, phenol, and p‐xylene) with the surficial functional groups of carbonaceous microspheres was investigated using density functional theory (DFT). Nucleophilic addition and dehydration are the main forms of polymerization reactions, and the former shows a lower reaction energy barrier than the latter by 100 kJ/mol, indicating that the nucleophilic addition reactions likely occur compared to dehydration reactions. And phenol likely promotes the growth of microspheres. In addition, the surficial furan ring structure of carbonaceous microspheres opened through ring opening, hydrogen atom transfer, and molecular space structure conversion in sequence. Among these reaction steps, the furan ring opening through hydration was the rate‐limiting reaction step, which showed the highest energy barrier with a value of 394.51 kJ/mol. However, the ring opening of furan rings could form more active sites, such as carbonyl groups, for subsequent polymerization reactions, indicating an increased potential for further reactions with aqueous‐phase organic components.

Energy efficiency of bio-coal derived from hydrothermal carbonized biomass: Assessment as sustainable solid fuel for municipal biopower plant

The utilization of conventional biomass to generate electricity in the biomass thermal power plant is still inefficient due to high content of moisture, high impurity, and low heating value. To explore this limitation, in this research, hydrothermal carbonization (HTC) was selected as a sustainable process for producing green solid fuel or bio-coal with a rich of carbon content from palm shell and bamboo, remarkably as model biomass raw materials. The effect of biomass to water weight ratio (1:1 to 1:10), reaction temperatures (160 – 250 °C), and reaction times (1 – 6 h) were performed under autogenous pressure of promising aqueous media. The effect of organic and inorganic acid adding in the HTC of palm shell and bamboo was discussed. The obtained bio-coal was further well characterized with proximate and ultimate analysis and fuel properties. From the results, increasing reaction temperature and adding of acids led to increase carbon content, resulting to increase HHV of bio-coal. Effects of feedstocks (palm shell and bamboo), temperature, and types of acids revealed significantly results on the bio-coal yield accompanied with carbon content, the higher heating value (HHV), energy densification, and energy yield. The addition of inorganic acid in the HTC of biomass with high cellulose content provided higher HHV improvement than that of stony biomass. The highest HHV of 27.9 MJ/kg was obtained in bio-coal derived from palm shell feedstock with 1:1 water ratio and hydrothermally at 250 °C for 6 h. Surprisingly, this HHV is comparable to high-volatile bituminous coal. Moreover, an evaluating assessment for the utilization of this bio-coal instead of biomass feedstock to generate electricity in the thermal power plant with size of 9.9 MW capacity could reduce 34.4 % of fuel storage size, save nearly 29,709.36 USD/year in transportation costs and diminish CO2 emission during burning by approximately 56,732 tons/25 years.

Dynamics of liquid-phase platform chemicals during the hydrothermal carbonization of lignocellulosic biomass

This paper studies the dynamics of process waters from hydrothermal carbonization of lignocellulosic biomasses, exploring the production of platform chemicals via the autohydrolysis of raw materials. Isothermal (200 °C) batch reactions went up to 2 h at a 7/1 liquid/solid ratio treating three wooden residuals, silver fir, beech, and olive. The distribution of liquid-phase chemicals depends on the biomass strongly. The peak concentrations of chemicals (furfural, 5-hydroxymethylfurfural, and lactic, formic, propionic, levulinic, and acetic acids) occur within 60 min of reaction. Biomass to chemicals conversion is up to 13 % (60 % of the total dissolved organic carbon). Simple equations describe system dynamics (R2 close to 0.99). UV and Vis optical density of the process waters monitors the reaction progress satisfactorily.The results foreshadow innovative process schemes for simultaneously converting biomass to energy and value products by recovering of furfurals during waste biomass hydrothermal carbonization.

Influence mechanism of aqueous organic components on the hydrochar formation reaction during the biomass hydrothermal carbonization wastewater recycling

Reusing the wastewater byproduct of the hydrothermal carbonization (HTC) process as a water source to prepare biomass slurry feedstock for the next HTC run provides a feasible wastewater disposal method. However, the influence of various organic components contained in the hydrothermal wastewater (HW) on the formation routes and characteristics of hydrochar is yet to be clarified. In this study, five representative organic components, phenol, acetic acid, furfural, 5-hydroxymethylfurfural (5-HMF), and 2,5-hexanedione, were selected to study their effects on the hydrochar fuel characteristics and HW components, based on which the hydrochar formation pathways in an organic wastewater environment were proposed. The phenol, furfural, and 5-HMF contained in the wastewater source could polymerize with the active intermediates from biomass degradation, thereby resulting in an increase in the hydrochar mass yield (HCY) by 1.13%–7.07% and an increase in the higher heating value of hydrochar to 27.36 MJ/kg. In contrast, the acetic acid and 2,5-hexanedione contained in the wastewater source resulted in a decrease in HCY, probably because of the catalytic effects of volatile fatty acids on biomass hydrolysis. Moreover, wastewater sources with all five organic components increased the energy recovery efficiency from biomass to a high level of 97.28% under the two effects of deep polymerization and catalytic carbonization.

Hydrothermal carbonization of biomass: experimental study, energy balance, process simulation, design, and techno-economic analysis

Hydrothermal carbonization of biomass: experimental study, energy balance, process simulation, design, and techno-economic analysis

Influence Mechanism of Aqueous Organic Components on the Hydrochar Formation Reaction During the Biomass Hydrothermal Carbonization Wastewater Recycling

Influence Mechanism of Aqueous Organic Components on the Hydrochar Formation Reaction During the Biomass Hydrothermal Carbonization Wastewater Recycling

Density Functional Theory Simulation of Heterogeneous Polymerization Reactions During Biomass Hydrothermal Carbonization Process

Density Functional Theory Simulation of Heterogeneous Polymerization Reactions During Biomass Hydrothermal Carbonization Process

Density Functional Theory Simulation of Heterogeneous Polymerization Reactions During Biomass Hydrothermal Carbonization Process

Density Functional Theory Simulation of Heterogeneous Polymerization Reactions During Biomass Hydrothermal Carbonization Process

Seed Germination and Seedling Growth Responses to Different Sources and Application Rates of Hydrothermal Carbonization Processed Liquid

Hydrothermal carbonization processed liquid (HTCPL) is a by-product of hydrothermal carbonization of biomass, which is used sparingly as natural fertilizer. A study was performed in the Faculty of Agriculture, Dalhousie University (Canada) between June 2019 and April 2020 to evaluate the elemental composition of HTCPL derived from three different biomass feedstock; namely, seafood compost; buckwheat (Fagopyrum esculentum), and willow (Salix babylonica). Different HTCPL application rates (0-10%) were tested on seed germination and seedling growth of pea (Pisum sativum), sunflower (Helianthus annuus), pac choi (Brassica rapa subsp. chinensis), kale (Brassica oleracea var. sabellica) and lettuce (Lactuca sativa). Elemental composition was higher in the HTCPLs compared to their respective feedstocks except for nitrogen. The 5% and 10% willow HTCPL with a pH between 3.8-4.0 inhibited seed germination and seedling growth compared to the other treatments with a pH range between 4.6-5.8. Kale, lettuce and sunflower radicle and hypocotyl growth were promoted following treatments of their respective seeds with seafood compost HTCPL while pea radicle and hypocotyl lengths were best promoted by 5% buckwheat and 10% seafood compost HTCPLs. Comparatively, 0.5% willow HTCPL increased surface area of seedling radicles while 1% willow and 0.5% buckwheat HTCPLs increased surface area of hypocotyls, irrespective of plant species. The distinction among the treatments was demonstrated on a 2-dimensional principal component analysis biplot that explained 89% of the variations in dataset. Overall, buckwheat HTCPL proved to be more effective at increasing seed germination and seedling growth compared to the other HTCPLs. The inhibitory effect of willow HTCPL at high application rate (5-10%) were obvious for all plant species. A comprehensive non-targeted chemical profile of HTCPL will help to explain mechanisms.