Waste Blends Research Articles

Co-pyrolysis of municipal and horticultural wastes for enhanced biochar and bio-oil production: A response surface methodology approach

Pyrolytic biochar is a promising approach to the withdrawal of CO2 and reduction of Green House Gases. One of the effective techniques to improve the properties of biochar with desired characteristics is co-pyrolysis of types of biomass. Among the types of biochar, biochar from nitrogen-rich biomass pyrolysis has various applications, including soil amendment and removal of organic pollutants. The aim of this study is co-pyrolysis nutrient-rich municipal (household) and horticultural wastes for N-doped biochar production and provide optimal conditions for the production of pyrolytic products. A series of experiments were designed with municipal and horticultural wastes at different mass ratios in a fast catalytic reactor at 550 °C with varying catalyst amounts (0–15 %) and waste blend ratios (0–100 wt%) were designed using the response surface methodology. The yields of bio-oil, biochar, and biogas were quantitatively and qualitatively assessed. Statistical analysis showed that that the horticultural-to-household wastes ratio has the most critical effect on the biochar yield. The optimum N-doped biochar yield (26 wt%) was achieved at the household-to-horticultural wastes ratio of 1.5 without using the catalyst. Also, the result showed that adding municipal waste increased bio-oil yield significantly from 18 % to 58 %. Moreover, increasing the catalyst amount raised gas yield to 37 %, and horticultural waste favored biochar formation (53 %). The optimized product showed carbon enrichment and oxygenated compound reduction the result is bio-oil production with a higher heating value. Gas chromatography-mass spectrometry (GC–MS) analysis of volatile products indicated that the co-pyrolytic oil was rich in N-containing compounds (Pyrrole, Pyridine, and Indole)which is widely used in pharmaceutical and polymer industries. Synergistic interactions between municipal and horticultural wastes significantly reduced the amount of carboxylic acids, alcohols, ketones, and esters, whereas phenols formation as valuable chemicals were increased. Therefore, this study shows that co-pyrolysis is a suitable approach for household and horticultural waste management that can increase the production of N-doped biochar and also be a sustainable source for the extraction of nitrogen-containing biochemical products.

A hybrid optimization approach towards energy recovery from torrefied waste blends

The bottleneck of urban forest waste (UFW) as biofuel relies on surpassing its logistical management, feedstock quantity and supply, heterogeneity, and property drawbacks. This article proposes a hybrid approach based on multicriteria decision methods (MCDM) and response surface methodology (RSM) to optimize the definition of UFW blends and their torrefaction (temperature and process time). First, proximate, ultimate, and calorific analysis of UFWs (S1.Mangifera indica, S2.Ficus benjamina, S3.Pelthophorum dubium, S4.Persea americana, S5.Anadenanthera colubrina, and S6.Tapirira guianensis) were assessed. Then, understanding that UFW relies on species that do not always show promising characteristics as biofuels, the MCDM was applied to feedstock properties defining an optimum blend (OB) composed of 73%, 12.5%, and 14.5% of S1, S5, and S6, respectively. Next, the OB torrefaction was optimized using a central composite design (RSM-CCD), providing prediction models, the optimum torrefaction condition (273.3 °C and 40 min), and a torrefied optimum blend (TOB). Finally, the approach was validated by assessing TOB's properties, combustion behavior, and gaseous emissions. The methodology supplied a TOB with lower ash (2.67%), an HHV of 20.87 MJ kg−1, reduced nitrogen content (up to 39.65%), and more stable combustion resulting in a superior solid biofuel with a lower potential of NO-emissions in further applications.

Effects of electric arc furnace slag powder and fly ash within ternary waste blend on performance of concrete

Recently, research on utilising industrial and natural waste has advanced owing to their environmental concerns, including soil and groundwater contamination. Most such waste possess zero or low commercial value, yet it is stored, occupying large storage yards. Iron and steel factories and quarries worldwide produce large amounts of waste annually. This study used three types of steel mill waste (electric arc furnace slag powder, fly ash and steel sludge and natural waste from quarries limestone dust, marble dust, and recycled glass powder) as supplementary cementitious materials with the aim of producing an economical and environmentally friendly ternary waste binder. To determine the appropriate waste blend compounds of mixes, the study was conducted in three stages. First, waste mortars were used to mix, tests of mortars properties were conducted, and the properties of the mix were compared with those of a control mortar mix. Second, concrete was mixed from the waste blend with the most suitable properties. Finally, durability tests on the concrete were performed. Ternary residue having 4.5% SP, 10% FA, and 4.5% SS with 18% replacement of cement and that having 3.75% SP, 7.5% FA, and 3.75% LD with 15% replacement of cement achieved the requirements of concrete and improved the compressive strength and durability towards sulfate and chloride attack, including impermeability and resistance.

Optimization of Textile Waste Blends of Cotton and PET by Enzymatic Hydrolysis with Reusable Chemical Pretreatment.

Textile waste usually ends up in landfills and causes environmental pollution. In this study, pretreatment methods for textile recycling, including autoclaving, freezing alkali/urea soaking, and alkaline pretreatment, were applied to textile waste with various cotton/polyester blending ratios. The best condition for enzymatic hydrolysis was a 60/40 textile waste blend of cotton/polyethylene terephthalate (PET) with a reusable chemical pretreatment (15% NaOH) at 121 °C for 15 min. The hydrolysis of pretreated textile waste by cellulase was optimized using response surface methodology (RSM) based on central composite design (CCD). The optimized conditions were 30 FPU/g of enzyme loading and 7% of substrate loading, which resulted in a maximum observed value of hydrolysis yield at 89.7%, corresponding to the predicted value of 87.8% after 96 h of incubation. The findings of this study suggest an optimistic solution for textile waste recycling.

Pyrolysis Processes and Physiochemical Properties of Liquid Hydrocarbon Fuel from Waste Plastics

AbstractPyrolysis of blended waste plastics into valuable chemicals such as fuel by using various catalysts is a vital and successful method at 350–500 °C. Virgin plastic can be recycled in plastic products once or twice only due to the loss of mechanical properties. The pyrolysis process is an important method for minimizing waste plastics and the need for alternative fuel sources that can at least replenish petrochemical resources. The quality of liquid green fuel depends on the distillation method of plastics with a heating range. Physiochemical parameters determined the qualities of the fuel, and their results were found to be equal to commercial fuel. This green fuel can be used as a transportation fuel and chemical feedstock for refineries without any upgrading. Liquid petrochemicals as fuel from waste plastics have been found to have good density values.

Effect of torrefaction on steam-enhanced co-gasification of an urban forest and landfill waste blend: H2 production and CO2 emissions mitigation

This study aims to simulate the steam-enhanced co-gasification of hybrid blends (HB) composed of municipal solid waste (MSW) and urban forest waste (UFW), with torrefaction as pretreatment. Experimental (torrefaction), numerical (gasification thermodynamic equilibrium model), and optimization (response surface methodology) techniques evaluated the gasification process to produce (i) hydrogen-rich gas or (ii) enhanced calorific value gas. The torrefaction (225–275 °C), steam-to-biomass (0.4–1.2 S/B) ratio, and HB proportion (0–50% of MSW) influences were investigated to assess H2%, exergy efficiency of H2-production (ηH2), lower heating value (LHV), cold gas efficiency (CGE), and CO2%. The hybrid methodology defined the optimal conditions for 600 °C gasification as (i) 0.9 S/B and an HB comprising 31% MSW and 69% torrefied UFW at 275 °C, presenting an ηH2 of 49%; and (ii) 0.4 S/B and an HB containing 23% MSW and 77% torrefied UFW at 275 °C, showing an LHV of 6126 kJ.Nm−3.

Correlations between product distribution and feedstock composition in thermal cracking processes for mixed plastic waste

Thermal conversion can transform the carbon-based waste into valuable chemicals to be further used in the petrochemical industry for a polymeric carbon circular economy. This work’s aim was to identify chemical correlations between the thermal-cracking products and the feedstock polymer composition when using highly blended waste streams. The challenges addressed were to: (i) access a pool of experimental data on the monomer recovery potential of real-life, highly blended waste streams; (ii) estimate the polymer constituents of the mixed waste streams; and (iii) formulate a generic and systematic method to identify correlations between feedstock constituents and cracking products. Different post-consumer waste streams were investigated, including cardboard, automotive shredder residues, cable stripping waste, and textile waste. The cracking experiments were performed in a 2–4MWth industrial-scale Dual Fluidized Bed system at 800 °C using steam as fluidization agent. The polymeric constituents of the feedstocks were estimated using a numerical convex optimization method. To identify correlations between the feedstocks and products, a carbon bond-based classification was introduced. The experimental monomer yield ranged from 0.08 kg/kgf to 0.3 kg/kgf (f = feedstock) for the evaluated materials, corresponding to a carbon feedstock conversion rate between 14 % and 44 %. High yields of valuable monomers were obtained for the materials with the highest polyolefin content. The olefin monomer production correlated positively to the amount of aliphatic carbon in the original material and negatively to the carbon contents of the aromatic rings. From the trends observed, it was concluded that a framework based on carbon bond types is a promising approach to identify such correlations, which could serve as predictive tools for monomer recovery based on material’s composition and overall process conditions.

A pilot-scale experimental study on MILD combustion of sawdust and residual char solid waste blend using low-temperature preheating air

The treatment of solid waste through incineration has become an important development trend. A solid waste blend (sawdust and residual char) is studied experimentally in a tubular-furnace reactor and a 200-kW pilot-scale furnace under moderate or intense low-oxygen dilution (MILD) combustion conditions. The effects of temperature and oxygen concentration on NO release characteristics are examined in the tubular-furnace reactor. The pilot-scale furnace experiments include the conventional flame combustion using a swirl nozzle (CFC-S), MILD combustion using symmetrical dual straight nozzles (MILDC-SD), and MILD combustion using an asymmetrical single straight nozzle (MILDC-AS). The tubular-furnace reactor results indicate that the NO released from solid waste blend mainly originates from fuel-NO under medium temperature and low oxygen environments. The pilot-scale furnace results demonstrate that stable combustion of the solid waste blend can be achieved under three co-combustion conditions. Compared to CFC-S, the MILDC-AS combustion of solid waste blend inhibits the fuel-NO and PM2.5 emissions by 54% and 50%, respectively. The burnout rates of solid waste blend MILD combustion exceed 95%. This study not only extends the fuel adaptability of MILD combustion to solid waste blend, but also proves the suppression influence of MILD combustion on fuel nitrogen and PM2.5 emissions.

Fabrication and analysis of structural material using paper and medical wastes

It has been understood that billions of trees are being cut every year across the world for making paper from various studies and sources. These papers are put in use in almost every organization and finally after they are used, it is dumped in landfills or dump yards. Apart from the Paper waste, the amounts of medical waste generated from medical activities are also huge. Specifically in this pandemic situation usage of disposable masks has increased which is contributing a good percentage of wastes in the landfills. If these wastes are effectively utilised, it can make us achieve cleaner environment and provides healthy human life. In order to minimise the accumulation of these wastes, these wastes are utilised to fabricate a brick which can be used for construction purposes. In this project, a blend of medical waste and paper waste are used to fabricate a brick. This is done by proper selection and processing of that medical waste and then mixing them with shredded papers in presence of water and binders. It is expected that this project will be a step towards sustainable development and prevents Environmental pollution. It is also expected that the fabricated structural material i.e., brick, will minimise the weight of the commercially available bricks in local market and possess all the properties that a normal brick is expected to have.

Effects of Electric Arc Furnace Slag Powder and Fly Ash within Ternary Waste Blend on Performance of Concrete

Effects of Electric Arc Furnace Slag Powder and Fly Ash within Ternary Waste Blend on Performance of Concrete

Co-combustion of multilayered plastic waste blend with biomass: Thermokinetics and synergistic effect

Improper management of inert plastic waste causes severe threats to the environment and leads to global climate change. The thermochemical combustion process adequately converts the plastic waste into a potential energy resourceas refuse-derived fuel (RDF), however, to get maximum energy yield, it is required to optimize the combustion process. Therefore, the physio-chemical and thermal characteristics of multilayer plastics (MLPs) and their blends with different biomassare determined under non-isothermal conditions. Five representative samples S1 to S5 which includes MLPs and their blend with biomass were selected for this study. Thermogravimetric analysiswas used to performthe combustion process with temperatures ranging from 30 °C to 1000 °C. It is noted that sample S1 has 77.87 % volatile matter, 8.30 % ash content, and 0.01 % sulfur and shows ahigher energy potential of 27.10 MJ/kg with minimum environmental emissions, demonstrating good agreement with theRDF I category. Thermo-kinetic parameters using the Coates-Redfern integral methoddemonstrated that the co-combustion follows a diffusion–reaction mechanism. The sequence of activation energy (Ea) and Gibbs energy (ΔG) follows in the order of S4 > S5 > S1 > S2 > S3. Moreover, the maximum Ea and ΔG required for the decomposition of these samples are in the range of 101–142 kJ/mol and 115–120 kJ/mol, respectively. It is concluded that the optimized S1 sample shows similar characteristics to conventional fuels and can be directly co-processed in cement industries or waste-to-energy plants. The obtained results can help in modeling and designing the thermochemical reactor for bench-scale operations.

Fundamental Study on Combustion Characteristics of Bio-briquette as Alternative Fuels for Domestic Coffee Stove

The aim of this study is to perform the effect of coffee waste blended in bio-briquette as an alternative fuel for domestic coffee stove. The sample of bio-briquette were blended with a variation of composition coffee waste, coal and polyvinyl acetate (PVAc) glue as a binder. The sample of bio-briquette was introduced in electric furnace with combustion atmosphere by using of 20% excess air condition. In the experiment, the mass reduction fraction, combustion rate, flame temperature of burning bio-briquettes was elucidated. The results obtained shows there are influenced of mass decreasing with an increasing of coffee waste blends, where the more of composition coffee wastes was added causes the faster of mass decreasing fraction of bio-briquette. The rate of combustion (K) increases with increasing percentage of coffee waste, where the largest K is obtained 6.05 (1 / second) in the composition of 90% coffee waste, while the smallest K of 4.55 (1 / second) is obtained in the composition of 30% coffee waste. The highest flame temperature occurs in the mixture of coffee waste 90% which is equal to 580 ° C and the lowest fire temperature occurs in the mixture of coffee waste 30% that is equal to 410 ° C.

The production of bio-based fuels and carbon catalysts from chicken waste

From an environmental and economic perspective, converting harmful waste materials into value-added products is very important. This work explores using an equal mixture of chicken waste (CW) and chicken bones (CBs) as a raw material for creating more valuable products. The CW (chicken skin and fat) were de-fatted, and their solid residue leftover was blended with CBs and utilized as a pyrolysis feedstock to create bio-oil (BO) and bio-char (BC). The waste blend was thermally pyrolyzed over a range of temperatures (400–600 °C) and periods (30–150 min) numerous range of heating rates (5–20 °C/min). The highest yield of liquid fractions (61.60%) was achieved at 500 °C for 120 min at a 10 °C/min rate of heating. The BO content of the liquid fraction amounted to 25.225%. According to the FTIR outcomes, the produced BO is a complex mixture of many organic compounds, including carboxylic acids, aldehydes, ketones, esters, and hydrocarbons (alkanes, alkenes, cyclic compounds, etc.). The fuel characteristics of the synthetic BO were similar to those reported for numerous samples of BO in the literature. It also offered its suitability as a synthetic fuel for engines and a probable source of chemical feedstock. The BC leftover after the pyrolysis of the waste mixture was exploited as catalyst support. It was impregnated with different ratios (10–50%) of KOH. The typical sample (40K/BC) was identified by SABET, FE-SEM, EDX, XRD, and FTIR spectroscopy. The efficiency and performance of the 40K/BC catalyst for transesterification of a blend of chicken fat and waste cooking oil to biodiesel (BD) were explored under diverse operating conditions. The highest BD yield (94.88%) was obtained in 90 min at 60 °C reaction temperature using a 4.0 wt% 40K/BC catalyst and 9:1methanol: lipid blend molar ratio. Additionally, the developed catalyst (40K/BC) demonstrated sustained activity after five cycles of recycling and reusing with a BD yield of >84.0%. The BD characteristics met the requirements of ASTM D6751 and EN 14,214. The ester content in the BD amounted to 96.36% based on 1HNMR analysis.

Oxy-fuel co-combustion characteristics and kinetics of various ultra-low volatile coal-based solid waste blends

Oxy-fuel co-combustion characteristics and kinetics of various ultra-low volatile coal-based solid waste blends

Study Progress on Inorganic Fibers from Industry Solid Wastes and the Key Factors Determining Their Characteristics.

Compared to basalt and glass fibers, the production of inorganic fiber from industry solid wastes is an effective method to not only save natural resources but also recycle waste resources. Because the preparation of the fibers requires high temperature treatment, the production process is associated with high energy consumption and high carbon emissions. How to resolve these problems is a current research challenge in this field. Herein, we reviewed the study progress on these fibers and further discussed the key factors determining their characteristics, including chemical composition, melt structure, and viscosity of melt. In production, the matching of solid waste blends containing enough total content of SiO2 and Al2O3, and a suitable amount of MgO and CaO, is beneficial to the structure control of the melt. The study found that the melt consisted of Q2 and Q3; and that Q3 content more than Q2 was more suitable for fiber production and its performance improvement. Such a melt structure can be achieved by controlling the degree of depolymerization and the temperature. New ultrasonic technology can shorten the homogenization time; its application is hoped to save energy and reduce carbon emissions. These conclusions will offer important guidance for the development of inorganic fibers from industry solid wastes in the future.

Effects of hydrogen and chicken waste blends in the internal combustion engines for superior engine performance and emission characteristics assisted with graphite oxide

PurposeThe demand for energy is increasing massively due to urbanization and industrialization. Due to the massive usage of diesel engines in the transportation sector, global warming is increasing rapidly. The purpose of this paper is to use hydrogen as the potential alternative for diesel engine.Design/methodology/approachA series of tests conducted in the twin cylinder four stroke diesel engine at various engine speeds. In addition to the hydrogen, the ultrasonication is applied to add the nanoparticles to the neat diesel. The role of nanoparticles on engine performance is effective owing to its physicochemical properties. Here, neat diesel mixed 30% of biodiesel along with the hydrogen at the concentration of 10%, 20% and 30% and 50 ppm of graphite oxide to form the blends DNH10, DNH20 and DNH30.FindingsInclusion of both hydrogen and nanoparticles increases the brake power and brake thermal efficiency (BTE) of the engine with relatively less fuel consumption. Compared to all blends, the maximum BTE of 33.3% has been reported by 30% hydrogen-based fuel. On the contrary, the production of the pollutants also reduces as the hydrogen concentration increases.Originality/valueMajority of the pollutants such as carbon monoxide, carbon dioxide and hydrocarbon were dropped massively compared to diesel. On the contrary, there is no reduction in nitrogen of oxides (NOx). Highest production of NOx was witnessed for 30% hydrogen fuel due to the premixed combustion phase and cylinder temperatures.

Synergetic biofuel production from co-pyrolysis of food and plastic waste: reaction kinetics and product behavior

This study aimed to develop a process for producing bio-oil, char, and value-added chemicals from food waste and plastic waste blend using co-pyrolysis under controlled conditions. The food waste (rice, vegetables, and fish) was blended in definite ratios (70:30, 60:40, and 50:50 w/w) with polyethylene terephthalate (PET). Experiments were conducted at various temperatures (250, 300, and 350 °C) and reaction times (30, 60, 90, and 120 min). A kinetic analysis was performed to fit experimental data, and reaction kinetics were observed to follow Arrhenius behavior. Maximum yields of bio-oil and bio-char, 66 and 40 wt% respectively, were attained at 350 °C, with yields being strongly influenced by variations in temperature and weakly affected by variations in reaction time. Co-pyrolysis promoted the formation of carboxylic acid, hydrocarbons, and furan derivatives. Formation of carboxylic acid could be increased by increasing the ratio of plastic waste. A maximum carboxylic acid content of 42.01% was achieved at 50% of plastic waste. Meanwhile, a maximum aliphatic hydrocarbon content of 44.6% was obtained with a ratio of 70:30 of food waste to plastic waste at 350 °C. Overall, pyrolysis of food and plastic waste produced value-added compounds that can be used as biofuels and for a variety of other applications.

Experimental investigation on the combustion, performance and emission characteristics of 1-pentanol blended waste plastic oil in a CRDI engine with EGR

Faster exhaustion of fossil fuels and escalation of pollution levels have increased the requirement for alternate fuels to fulfil the energy demand of the fast growing world. The present work attempts to use waste plastic oil added with 1-Pentanol in a CRDI engine to achieve comparable performances of pure diesel with significantly reduced hazardous emissions. The experiments were carried out with 10, 20 and 30% of 1-pentanol blended with waste plastic oil on volume basis. The experiments were conducted at constant speed of 2000 rpm with load varying from 20 to 80% and exhaust gas recirculation by 10 and 20%. The fuel blend with 30% 1-pentanol exhibited 3.3% lower efficiency, 0.02 kg/kWh higher brake specific fuel consumption, 74 ppm of lower nitrogen oxide and 2.3 ppm of higher hydrocarbon emissions correlated to pure diesel. The use of exhaust gas recirculation reduced nitrogen oxides in the exhaust gas with slightly aggravated emissions of carbon monoxide. Considering the different combustion, performance and emission parameters, the fuel blend containing 30% of 1-pentanol and 70% waste plastic oil can be a potential alternate to pure diesel.

Performance, emission, and exergy analysis of an IDI dual swirl combustor diesel engine with blended waste Chia seed oil as a biofuel

This study aims to investigate the performance characteristics of an IDI engine with a novel dual swirl chamber and using biodiesel from waste chia seed oil blended with diesel. To the author’s best knowledge, this is the first study on waste Chia seed oil as a fuel in IDI engine. The injection pressure and CR of the test engine were increased from their recommended values. Biodiesel blends BC05 to BC25 with diesel in volumetric ratios of 5% to 25% respectively with 5% increments were used for experiment purpose. The results showed that biodiesel blends have lesser BTE (from 2.2% to 5%) and higher BSFC (from 3.5 to 5.2%) compared with diesel due to lower CV. With the increase in injection pressure and CR, the difference in BTE and BSFC got reduced because of better atomisation and mixing. The CO and NOx emissions are 9.26% and 27% lesser for the BC20 blend.

New binary paper/wood industry waste blend for solidification/stabilisation of problematic soil subgrade: macro-micro study

This article presents the potential application of paper/wood industry waste by-products, i.e. lignosulphonate (LS) in conjunction with lime (LM) [i.e. LS-based cementing admixture (LSCA)] to mitigate desiccation induced cracking and mechanical vulnerabilities of expansive soil subgrade. The results showed that the LSCA and lime (LM) significantly ameliorated the soil consistency, subgrade strength characteristics (i.e. California bearing ratio and resilient modulus), and completely mitigated the swelling potential with enhanced resistance against Sr . Moreover, the LSCA and LM notably reduced the 3D-volumetric shrinkage and crack intensity factor (CIF) by 90.1 and 87.4%, respectively. The mineralogical and microstructural analyses manifested that the LSCA induced new cementitious compounds (i.e. hydrates of calcium silicate and calcium aluminate), and substantially enhanced the interlocking among the soil particles compared to the untreated and LS-treated soils. Besides, pavement thickness analyses showed that the LSCA treated subgrade, omits the provision of sand cushion and sub-base course promoting road material conservation.