Increase In Heating Value Research Articles

Optimization of traditional market solid waste conversion process into hydrochar using hydrothermal carbonization technology

Abstract In this study, an analysis was carried out to determine the optimum conditions for the hydrothermal carbonization process of traditional market waste using response surface methodology central composite design. The hydrothermal carbonization process was carried out at temperatures (180, 215, 250°C), process times (30, 60, 90 minutes), and a ratio (waste: water media) of 0,5. The results of response surface analysis show that temperature and process time are parameters that significantly affect the quality of hydrochar. Increasing temperature and process time resulted in a decrease in hydrochar weight from 67,01 to 40,77 grams. Furthermore, there was an increasing heating value of hydrochar from 18,87 to 30,5 MJ/Kg. The optimization formulation of the hydrothermal carbonization process of traditional market waste was obtained at a temperature of 181,133°C and a process time of 30 minutes with a prediction value of weight and heating value obtained, namely 61,39 grams and 23 MJ/Kg.

Chemical recycling of complex reject streams from the paper industry via thermal and catalytic pyrolysis

Paper-based packaging is a complex multi-material composed of paper (fibers), plastics, and metals, making efficient material recycling complicated. Currently, most of the fibers are recycled into new paper products while the residual material is commonly incinerated. Therefore, to improve the circularity and reduce the fossil dependency chemical recycling is needed. In this study, recycling of the residual materials was evaluated by thermal and catalytic pyrolysis. First, screening tests were performed using five reject materials and four catalysts in an analytical scale and then, a selection of catalyst and reject materials were evaluated in lab-scale followed by a techno-economic assessment. Experimental results indicated that the conversion was more efficient if the reject had high content of plastics compared to fibers, leading to products with increased heating value, higher hydrocarbon yield and less reactive oxygenates compared to the rejects with low plastic ratio. In the thermal pyrolysis 54 % of the weight of the feedstock and 70 wt% of the carbon in the feedstock ended up in a solid organic product (wax) which contained hydrocarbons and alcohols. In the analytical catalytic pyrolysis, HZSM-5 gave the best result in terms of cracking, deoxygenation, and aromatization. Ex-situ catalytic pyrolysis using HZSM-5 resulted in an improved quality of organic liquid with reduced hydrocarbon length as well as deoxygenated and aromatic compounds. The yield of the organic liquid was up to 19 wt% and contained mainly monoaromatics. The techno-economic evaluation showed, for processing 100,000 tons year−1 residual material, the total plant investment and the annual profit are about 29 and 12 million Euros, respectively, if no incentive for treating the residual material.

Multi-response optimization of charcoal briquettes process for green economy using a novel TOPSIS linear programming and genetic algorithms based on response surface methodology

The production of charcoal briquettes was based on the concept of utilizing waste for sustainable and eco-friendly solutions within the green economy. This study introduces a new approach for optimizing important properties of charcoal briquettes. The approach aims to determine the appropriate operating conditions using a hybrid method. It integrates a novel TOPSIS linear programming with genetic algorithms based on response surface methodology. The experiment used an optimal mixture ratio of 25:10:6, including coconut shell, bagasse ash, and corncob. The results of the responses showed increased heating value and burning time by 5.13 % and 5.71 %, respectively, and moisture content decreased by 15.12 %. Furthermore, confirmation experiments within a 95 % confidence interval verified that the three responses obtained at the optimal operating conditions of process factors. The total cost of charcoal briquettes is 0.903 USD/kg and a payback period of 4.85 years. This illustrates that process improvement also aligns with the broader goals of promoting green and a circular economy.

Characterization of the effect of pyrolysis in torrefied wood chips

The pyrolysis behavior of torrefied wood produced in Portugal was investigated. Torrefaction is the thermochemical upgrading of biomass at approximately 300ºC in an atmosphere free of oxidizing agents to increase fuel density and to improve fuel quality, decreasing moisture and increasing heating value. Torrefied woodchips were pyrolysed at pressurized conditions in an inert atmosphere at 600ºC. All the condensable liquids were sampled for analyses. All pyrolysis hydrocarbon liquids were analysed using simulated distillation (simdis) and gas chromatography mass spectrometry (GCMS). Torrefied wood hydrocarbon liquid showed higher concentrations of aliphatic aldehydes liquid. A decrease in all the other molecular components was observed for the torrefied wood hydrocarbon liquid. The main organic components in the torrefied wood pyrolysis water fractions were acids, alcohols and aliphatic oxygenates. Torrefied wood pyrolysis water exhibited a significantly lower acid concentration when compared to non torrefied wood pyrolysis water. The biomass chars (prepared at 600ºC) were analysed using proximate analyses and carbon dioxide char reactivity. Proximate analyses showed that volatile matter was still present in the torrefied wood, but was almost completely devolatilized after pyrolysis.

Torrefaction of kraft pulp mills sludges

Torrefaction emerges as an industrial process that increases the energy content of conventional biomass. Primary and secondary sludge are the main solid residues generated in the Effluent Treatment Plants of bleached kraft pulp mills, and can be considered as biomass. Typically, these wastes are sent to industrial landfills. The present study aimed to evaluate the technical feasibility of transforming the primary sludge (PS), secondary sludge (SS) and mixed sludges (MIX) into torrefied biomass for energy generation. Three temperatures (260, 290 and 320 °C) and three residence times (20, 40 and 60′) were used in the sludge torrefaction process. Increasing the torrefaction temperature and residence time of the sludges produced several benefits on their physical and chemical properties. They promoted an increase in the heating value, due to the elimination of less energetic compounds and the concentration of the fixed carbon content; caused a reduction of moisture, with a consequent increase in the lower heating value of the sludges; and led to a high energy yield and an increased energy density, important parameters in sludges energy generation. The treatment at 320 °C for 60′ obtained increases of 76%, 27% and 41% over the reference, for PS, SS and MIX, respectively.

Peningkatan Kualitas Biobriket dari Tandan Kosong Kelapa Sawit Melalui Torefaksi dengan Penambahan Co-Firing dari Tempurung Kelapa dan Sludge CPO sebagai Perekat

Indonesia is one of the world's leading producers of crude palm oil. This large production, however, creates a huge quantity of waste, one of which is empty palm fruit bunches. These empty fruit bunches have a high potential for use as a renewable energy source, such as in the creation of briquettes employing the torrefaction process with co-firing addition, with the goal of increasing their heating content. Furthermore, the goal of this research is to determine the best composition of co-firing with variation adhesive addition for increasing heating value and to compare the heating value, ash content, and volatile matter content of various compositions of co-firing. The study began with the preparation of raw material samples of empty palm fruit bunches and coconut shells. Torrefaction at 300°C for one hour is utilized. The torrefaction results are produced into briquettes with a variety of compositions of empty palm fruit bunches and coconut shells. CPO sludge is also used as an adhesive with concentrations of 20% and 30%. The briquettes produced with an addition co-firing from coconut shells fulfilled SNI requirements such as heating value, moisture content, volatile matter, and ash content. The best briquette quality is composed of 40% empty palm fruit bunches and 40% coconut shell, with a heating value of 6241.26 cal/g, 3.15% moisture, 5.8% ash, and 9.9% volatile matter.

Investigation of the Effects of Cohydrothermal Carbonization on the Physicochemical Characteristics and Combustion Behavior of Straw Hydrochars

The use of straw biomass for energy can reduce the use of fossil energy and alleviate air pollution. Herein, the cohydrothermal carbonization (Co‐HTC) of rice straw and wheat straw with corn straw is investigated, and synergistic effects of multistraw biomass are observed in the Co‐HTC process. When the corn straw ratio is 75%, the energetic recovery efficiency, C content, and heating value increase compared to the calculated values of the Co‐HTC products. At 260 °C, the energetic recovery efficiency increases by 8.96% and the heating value increases by 2.28 MJ kg−1, which is beneficial for its application. The positive synergistic effect is probably caused by the enhanced dehydration and decarboxylation reactions. For the combustion behavior analysis, the entire combustion process is divided into two stages. When the corn straw ratio is greater than 50%, compared to the calculated values of the Co‐HTC products, the comprehensive combustibility index and activation energy of stage I increase and the activation energy of stage II decreases at 180 °C, while the activation energy of stage I decreases and the activation energy of stage II increases at 260 °C. These findings demonstrate that the Co‐HTC of multistraw biomass is suitable for solid biofuel production.

Hydrothermal treatment (HTT) improves the combustion properties of regional biomass waste to face the increasing sustainable energy demand in Africa

The increasing worldwide energy demand in parallel to the increasing climate change effects require the utilization of sustainable energy sources. Biomass residues are a feasible energy source, but their chemical composition often compromises their utilization due to slag formation or high emissions. It is investigated in this study whether hydrothermal treatment (HTT) can improve the combustion properties of biomass residues from Ghana. Six biomass residues (Prekese pods, ground nut husks, coconut husks, cassava peels, shea cake, deoiled shea cake) treated at three temperatures (150 °C, 170 °C, 185 °C) were analyzed for combustion properties and emission precursors according to European Standards. The results were evaluated considering consistencies of combustion related properties and especially of ash element reduction behavior. There was a clear trend to increasing mass loss and increasing heating value with increasing treatment temperature that was reflected in the carbon, hydrogen and oxygen amounts, while the ash content and its composition varied. Consistencies in the ash element behavior were highlighted and discussed in order to identify chemical key parameters that led to or inhibited specific ash element reductions. HTT was identified as a feasible biomass upgrade method with advantages over water leaching at room temperature and high temperature hydrothermal carbonization in case of the availability of off-heat from e.g. biomass electricity production.

Pyrolysis of sawdust impregnated with xylose: Tailoring property of biochar with sugar-derived intermediates

Cellulose and hemicellulose are major components of woody biomass, pyrolysis of which would inevitably produce anhydrate sugars or sugar-like organics. These sugars might tailor property of biochar via interactions when they pass through inner and outer surface of biochar, which were investigated herein in pyrolysis of poplar sawdust impregnated with various loading of xylose, a model sugar from hemicellulose, at 600 °C. The results suggested that the addition of xylose enhanced the cracking reactions to form more gaseous products but less biochar and bio-oil. Nevertheless, the intermediates from xylose enhanced aromatization of volatiles to form more light phenolics while aided precipitation of heavy organics on surface of biochar. The accelerated carbonization, deoxygenation and dehydrogenation reactions with presence of xylose enhanced aromatization reactions, making the biochar carbon-rich with increased heating value, crystallinity and hydrophobicity. Additionally, xylose addition could substantially enhance thermal stability of the biochar, even with loading of only 5 wt%. The DRIFTS characterization showed that the degradation of xylose produced abundant carbonyls-containing species that react with organics on surface of biochar, forming large aromatics of fused ring structures.

Production, Characterization, and Activation of Biochars from a Mixture of Waste Insulation Electric Cables (WIEC) and Waste Lignocellulosic Biomass (WLB)

Waste insulation electrical cables (WIEC) currently do not have an added value, due to their physical–chemical characteristics. Carbonization is known to enhance feedstock properties, particularly fuel and material properties; as such, this article aimed to study the production and activation of biochars using WIEC and lignocellulosic biomass wastes as feedstock. Biochars were produced in a ceramic kiln with an average capacity of 15 kg at different temperatures, namely 300, 350 and 400 °C. After production, the biochars were further submitted to a washing process with water heated to 95 °C ± 5 °C and to an activation process with 2 N KOH. All biochars (after production, washing and activation) were characterized regarding an elemental analysis, thermogravimetric analysis, heating value, chlorine removal, ash content, apparent density and surface area. The main results showed that the increase in carbonization temperature from 300 to 400 °C caused the produced biochars to present a lower amount of oxygen and volatile matter, increased heating value, greater chlorine removal and increased ash content. Furthermore, the activation process increased the surface area of biochars as the production temperature increased. Overall, the carbonization of WIEC mixed with lignocellulosic wastes showed potential in enhancing these waste physical and chemical properties, with prospects to yield added-value products that activates biochar.

Improvement of energy recovery potential of wet-refuse-derived fuel through bio-drying process.

This paper proposes novel wet-refuse-derived fuel (Wet-RDF) bio-drying process with the variation of initial organic substrate and moisture content. The bio-drying was carried out using 0.3 m3 lysimeter aerated continuously at different rates. Two conditions of Wet-RDF feedstock tested included: Experiment A ‒ 37% organic substrate and 58% moisture content with an initial heating value of 2,889kcal/kg; and Experiment B ‒ 28% organic substrate and 35% moisture content with an initial heating value of 4,174kcal/kg. The bio-drying was performed in both experiments under negative ventilation mode and non-ventilation mode, the ventilation mode was set at the aeration rates of 0.2 m3/kg/day and 0.4 m3/kg/day. The results suggest that the optimum aeration rate was 0.4 m3/kg/day, achieving a 30% moisture reduction and a 60% heating value increase from their initial values. As a result, the improved wet-RDF qualified for the local cement industry's standard in terms of heating value.

Understanding the effects of feedstock blending and catalyst support on hydrotreatment of algae HTL biocrude with non-edible vegetable oil

The performance of cobalt-molybdenum (CoMo) on hydrotreating of algae HTL biocrude and carinata oil was investigated. Commercial CoMo/Al2O3 (CoMo/Al) and synthesized CoMo supported on Douglas fir biochar (CoMo/DF), sulfided or unsulfided catalysts, were compared for hydrodeoxygenation (HDO), hydrodenitrogenation (HDN), hydrodesulfurization (HDS) and hydrodemetallization (HDM) reactions. Results showed that there lies a synergistic effect when HTL algae biocrude and carinata oil blends are hydrotreated. The yield of the upgraded blend (UB) oils retrieved over alumina catalyst was higher than the individual hydrotreated parent oils. For example, a 9% and 5% increase in yield was noted compared to the average of individual hydrotreated parent oils. The UB produced from sulfided CoMo/Al exhibited superior HDO activity primarily by decarbonylation. This was apparent in increased heating value, carbon addition, higher octane number, and lower total acid number than the oils obtained from the biochar-supported catalysts. Sulfided CoMo/DF catalyzed cracking reactions which lowered the viscosity, followed by high HDN and HDS activity compared to the commercial catalyst. The two supports showed different sorption behaviors. Interestingly, CoMo/DF had an effective sorption mechanism that helped in higher metal removal from the oil. Additionally, presulfiding and DF support exhibited positive results in term of less coke formation. In brief, biochar supports have higher acidic sites, inorganic mineral oxides, ion exchange capacity, high surface area, pore structure and connectivity. All of these make a substantial contribution to its unique catalytic behavior.

Investigation on the effects of blending hydrogen-rich gas in the spark-ignition engine

In order to improve the energy efficiency of the internal combustion engine and replace fossil fuel with alternative fuels, a concept of the methanol-syngas engine was proposed and the prototype was developed. Gasoline and dissociated methanol gas (GDM) were used as dual fuels and the engine performance was investigated by simulation and experiments. Dissociated methanol gas is produced by recycling the exhaust heat. The performance and combustion process was studied and compared with the gasoline engine counterpart. There is 1.9% energy efficiency improvement and 5.5% fuel consumption reduction under 2000r/min, 100 N ⋅ m working condition with methanol substitution ratio of 10%. In addition, the engine efficiency further improves with an increase of dissociated methanol gas substitution ratio because of the increased heating value of the fuel and effects of hydrogen. The peak pressure in the cylinder and the peak heat release rate of the GDM engine are higher than that of the original gasoline engine, with a phase closer to the top dead center (TDC). Therefore, blending hydrogen-rich gas in the spark-ignition engine can recycle the exhaust heat and improve the thermal efficiency of the engine.

Efficient extraction of biodiesel feedstock and dehydration of kitchen waste: A method based on co-dissolution of liquefied dimethyl ether and water

In the context of low-carbon development, as a waste rich in lipids, kitchen waste (KW) has received increasing attention for resource utilization and low-carbon utilization. In this study, we explored a method for efficient extraction of lipids and dehydration using liquefied dimethyl ether (L-DME) to address the problem of high lipids and the difficulty of dewatering of KW. A closed DME reaction vessel was used to conduct experiments on the effects of lipids extraction and dehydration of KW under different reaction times, mass ratios, temperatures and moisture contents. It was found that DME could extract more than 90% of the lipids and the dehydration rate could reach approximately 80%. The main components of the lipids in the liquid phase extract were fatty acids (C18:2, C18:1, C16:0, and C18:0) whose good thermal properties made them suitable for use as a feedstock for biodiesel production. Moreover, the greatly increased heating value of the solid residue facilitated low-carbon utilization. This study also demonstrated a promotion effect of the co-dissolution system of L-DME and water on the extraction of lipids and explored the related mechanism.

Investigation on the water-washing of corn straw for de-ash, de-chlorination, and increase of heating value through response surface methodology

Investigation on the water-washing of corn straw for de-ash, de-chlorination, and increase of heating value through response surface methodology

Improvement of Biocoal Quality from Empty Oil Palm Fruit Bunches by Using Peat Water to Reducing Potassium Content and Torrefaction at 300°C to Increasing Heating Value

Consumption of fossil energy continues to increase and therefore fossil energy reserves are decreasing, thus the switchover of using fossil energy into new and renewable energy is necessary. Biomass especially from oil palm empty fruit bunches is one of potential resource as new and renewable energy that can mixture with coal as fuel for power plant. However, biomass from oil palm empty fruit bunches has several weaknesses as fuel; it is containing of high potassium content and low heating value. Potassium content will react with oxygen and resulting potassium oxide (K2O) in the furnace of boiler and it can cause the fouling and slagging at the tubes and walls of boiler. Washing with flowing peat water is one of method that used to reduce potassium content in empty oil palm fruit bunches and torrefaction at 300C is a method is use to increase the heating value of biomass from empty oil palm fruit bunches. This research resulted the potassium, potassium oxide content is 5% and 3.7% respectively by flowing peat water at 5 lpm for 60 minutes, and the heating value of biomass by torrefaction process at 300C for 30 minute was obtain at 28742.17 kJ/kg.

Influence of torrefaction on yields and characteristics of densified solid biofuel

Torrefaction is a mild thermal pretreatment for enhancing the combustion property of biomass to be properly applied to biomass or co-firing power plants. The present research investigated mass yields, fuel characteristics and hydrophobicity of rubber wood pellet torrefied at different temperatures and residence times. Proximate and ultimate analyses, the enhancement factor of higher heating value, energy yield, lignocellulosic components and Fourier transform infrared spectroscopy (FT-IR) of torrefied samples were performed to evaluate the influence of the process parameters and compared to those of the untreated ones. The non-condensable and condensable products were analyzed by GC and GC-MS. The results showed that the torrefaction severity index (TSI) correlated sufficiently with the properties of torrefied biomass and was more sensitive to torrefaction temperature than residence time. The increase in the TSI value resulted in an increase in heating value but a decrease in energy yield. The energy density increased by 14% at 260 °C and reached up to 35% at torrefaction temperature of 300 °C. FT-IR analysis revealed that the contents of hydroxyl and carbonyl groups appeared in torrefied wood pellets were decreased and increased, respectively, due to the torrefaction process. Furthermore, the hydrophobicity of torrefied pellets can be significantly improved as torrefaction temperature increases. The non-condensable gaseous products were mostly composed of CO2, CO, and traces of CH4. While the organic compounds found in condensable liquid products were acids, ketones, furans and phenols.

Comparison of Fuels and Effluents Originating from Washing and Hydrothermal Carbonisation of Residual Biomass

A series of four different biomass feedstock was washed and hydrothermally carbonized at temperatures of 50 °C and 150–270 °C for four hours, respectively. For the first time both the resulting solid and liquid products were characterised and evaluated in a comprehensive study. Concerning fuel properties, HTC had a higher impact on the fuel quality than washing. HTC yielded hydrochar with higher carbon content than the starting material leading to a significant increase in heating value, while washing only had a minor effect on elemental composition and heating value. Treatment temperature was found to have the highest impact on LHV and elemental composition. Both washing and HTC proved effective in reducing potassium and chlorine content, while earth alkaline, phosphorous and silicon removal was limited. Process water characterisation revealed that filtrates from washing and HTC are acidic, with acidity being increased by HTC. Electrical conductivity of the effluent was found to correlate with the amount of electrolytes Na, K, Mg and Ca in the feedstock, thereby being feedstock dependent. COD, BOD5 and TOC values determined revealed that effluent from both washing and HTC is strongly contaminated by organic matter. The organic load was significantly higher in HTC effluents. Feedstock type was found to be the main influencing factor on effluent characteristics rather than HTC temperature. Nutrients were found in low concentrations.Graphic

Heat Quality Enhancement and Carbon Dioxide Emissions Reduction from Coal Burning by Combining Low-Ranked Coal with Biomass Waste as A Clean Energy Solution to Achieve Energy Security in Indonesia

Indonesia is the fifth largest coal producer in the world with coal reserves reaching 39.56 billion tonnes. Coal reserves of medium and high quality are expected to be exhausted in 2048, therefore it is necessary to utilize low-ranked coals. Low-ranked coals have a low heating value (<5,100 kcal/kg) and produce greater CO2 emissions compared to medium and high rank coals. One method to increase heating value and reduce CO2 emissions from low-ranked coals is through the Utilization of hybrid coal. Hybrid coal is low quality coal combined with biomass waste and has undergone a pyrolysis process together. The mixing and co-pyrolysis of low-ranked coal with biomass waste such as rice husk, empty palm fruit bunches, and rubber wood with a ratio of 7:3 is known to be able to increase the final product calorific value by 31.10–44.12% and reduce non-neutral CO2 emissions by 15.56–21.31%. The hybrid coal production process is highly prospective to be implemented in Indonesia, especially in Central Java, South Sumatra and South Kalimantan. The payback period from the hybrid coal industry with a production capacity range of 540 thousand to 4.5 million TPY can be achieved in 10–13 years with a net profit range of IDR 137 billion to IDR 493 billion per year and a net present value range of IDR 285 billion to IDR 1.1 trillion.

Investigating Compatible Drying Technique for Safe Utilization of Thar Coal, Pakistan

ABSTRACT To enhance the combustion efficiency of high moist coal, it is important to reduce its moisture contents. For reduction of moisture contents, the selection of efficient and low-cost drying technique based on the coal characteristics is helpful to convert the high moist coal to good quality fuel. A total of 18 Thar coal (Pakistan) samples were crushed and sieved at following size fractions (355, 500, 710 µm). These samples were dried using different techniques, namely, solar-drying, hot air-drying, oven-drying, microwave oven-drying, and flue gases drying. The morphological, physical, and chemical changes were investigated for the effectiveness of different techniques to make the Thar coal as a value-added fuel. The applied drying techniques showed a significant reduction in moisture contents from the Thar coal samples (38.11 to 7.78%). However, the flue gases drying and air-drying techniques showed highest reduction in moisture content (29–31%). Similarly, 35% increase in heating value (HV) J/kg was observed in case of flue gases drying technique. These results indicated that the flue gases and air-drying techniques may be used to reduce the moisture contents and enhance the HV of high moist Thar coal that can be used as value-added fuel in the country.