Solid- liquid phase separation and resource recycling study for waste rolling oily sludge

On the basis of the characteristics of a highly emulsified solid-liquid phase （fine particles, sticky consistency,black color, and low reuse ratio）, waste rolling oily sludge has been a focal problem in the steel industry. In this article, a solid-liquid phase separation and resource recycling process was described, with pilot test results showing that flocculation-sedimentation is an effective pretreatment, and that the filtration-coagulationvacuum distillation process is simple and feasible with a 53.5% recovery rate for regenerated oil that is qualified for return to the roiling production line. Then,solid phase oil-sludge was extracted by solvents with a 77% metal resource recovery rate and a wide utilization range. Finally, according to the experimental results, a set of feasibility plans for a 50 t/a waste rolling oily sludge solid-liquid separation and resource recycle project was designed, with the expectation of 50% regenerated oil yield, 70% solid metal resource recovery, and a 2. 5-year investment payback period.

Cost-effective,environmentally-sustainable and scale-up synthesis of vertically oriented graphenes from waste oil and its supercapacitor applications

Vertically oriented graphenes(VGs)have attracted tremendous attention in a variety of energy storage-related applications.However,the high cost of preparing VGs significantly hinders their practical applications.Herein we introduce the Ar-plasma-enhanced chemical vapor deposition to demonstrate the cost-effective,environmentally-sustainable,and scale-up synthesis of VGs from waste oil.In our system,Ar gas can improve the electron energy and ionization rate of plasma,which breaks down the chemical bonding of waste oil into essential species to etch the amorphous carbon,yielding large-area VGs(12×3.5 cm^(2))with highly-oriented structure and superior growth efficiency beyond VGs from hydrocarbon precursors.In the supercapacitor applications,the VG-based electrode exhibits significantly enhanced capacitance(~4 times that from conventional hydrocarbon gases)and efficient AC(alternating current)filtering capability RC(resistor-capacitor)(time constant of of 163μs at 120 Hz),which is obviously superior to the non-oriented counterpart.Besides,MnO_(2)/VGs composite electrode is prepared to deliver a maximum energy density of~33.2 Wh/kg at 1.0 kW/kg and a power density of 10.2 kW/kg at 22.9 Wh/kg.In the end,the economic analysis suggests that the total cost of VGs can be reduced by~32%.This work provides an environment-friendly and low-cost avenue for preparing VGs for advanced energy storage applications.

Biodiesel from fish waste oil: synthesis via supercritical methanol and thermodynamic optimization

This study evaluates the potential of local fish waste oil as a feedstock for biodiesel via supercritical methanol transesterification(SCMT).Hexane was used as a cosolvent and the transesterification reaction was carried out in a continuous reactor under supercritical conditions.The response surface methodology(RSM)method was applied to analyse the effect of four independent variables,including the weight ratio of methanol to fish-waste oil(W),the reaction temperature(T),the pressure(P)and the feed flow rate(F),on the yield of the biodiesel production in supercritical methanol.According to the calculated optimal operating condition for the RSM,the values of W(22.3 weight ratio of methanol to fish waste oil),T(270°C),P(112.7 bar)and F(2.0 mL min-1)were achieved.Under the optimum conditions,the highest yield was estimated to be 94.6%(g/g).The obtained yield was found to be close to the theoretical yield(95.2%).This value suggests that the proposed strategy has a promising potential in the production of biodiesel fuel.

Diffusion and Regeneration Mechanism of Waste Composite Oils Rejuvenator in Aged Asphalt

The physical performance of recycled asphalt was used as the main evaluation index to study the optimal range of a self-made rejuvenator.Through the penetration,viscosity and gel permeation chromatography(GPC)tests,the diffusion degree of the rejuvenator under different temperatures and time process was analyzed,and the diffusion efficiency of the rejuvenator was evaluated from the macro and micro perspective.The regeneration mechanism of the rejuvenator in the aged asphalt was also analyzed using the Fourier transform infrared spectroscopy(FTIR),scanning electron microscope(SEM)and chemical composition tests.The research results showed that the optimum rejuvenator content was about 3%.Higher temperature and longer time were beneficial to improving the permeability and diffusion of the rejuvenator.During the aging process,the light components were reduced,and more macromolecular asphaltenes were generated as well as a large number of carbonyl and sulfoxide.After diffusion and regeneration,the light components in the asphalt were supplemented,the wrinkles and gullies of the aged asphalt were almost improved to the surface state of the matrix asphalt.

Investigation of performance and emission characteristics of waste cooking oil as biodiesel in a diesel engine

Biodiesel is one of the most popular prospective alternative fuels and can be obtained from a variety of sources. Waste frying oil is one such source along with the various raw vegetable oils. However, some specific technical treatments are required to improve certain fuel properties such as viscosity and calorific value of the biodiesel being obtained from waste cooking oil methyl ester （WCOME）. Various treatments are applied depending on the source and therefore the composition of the cooking oil. This research investigated the performance of WCOME as an alternative biofuel in a four-stroke direct injection diesel engine. An 8-mode test was undertaken with diesel fuel and five WCOME blends. The best compromise blend in terms of performance and emissions was identified. Results showed that energy utilization factors of the blends were similar within the range of the operational parameters （speed, load and WCOME content）. Increasing biodiesel content produced slightly more smoke and NOx for a great majority of test points, while the CO and THC emissions were lower.

Extraordinary Compatibility to Mass Loading and Rate Capability of Hierarchically Porous Carbon Nanorods Electrode Derived from the Waste Tire Pyrolysis Oil

The conversion of waste tire pyrolysis oil(WTPO)into S-doped porous carbon nanorods(labeled as WPCNs)with hierarchical pore structure is realized by a simple template-directed approach.The specific surface area of as-obtained porous carbon nanorods can reach up to 1448 m^(2) g^(−1) without the addition of any activating agent.As the capacitive electrode,WPCNs possess the extraordinary compatibility to capacitance,different electrolyte systems as well as long-term cycle life even at a commercial-level areal mass loading(10 mg cm^(−2)).Besides,only an extremely small capacitance fluctuation is observed under the extreme circumstance(−40 to 80℃),reflecting the excellent high-and low-temperature performance.The relationship between the pore structure and capacitive behavior is analyzed by comparing WPCNs with mesopores-dominated asphalt-derived porous carbon nanorods(APCNs)and micropores-dominated activated carbon.The molecular dynamics simulation further reveals the ion diffusion and transfer ability of the as-prepared carbon materials under different pore size distribution.The total ion flow(NT)of WPCNs calculated by the simulation is obviously larger than APCNs and the N_(T) ratio between them is similar with the experimental average capacitance ratio.Furthermore,this work also provides a valuable strategy to prepare the electrode material with high capacitive energy storage ability through the high value-added utilization of WTPO.

Rheological properties and microscopic mechanism of waste cooking oil activated waste crumb rubber modified asphalt

In this paper,the surface activated crumb rubber with waste cooking oil(WCO)was studied to improve the performance of crumb rubber modified asphalt.The activated waste crumb rubber modified asphalt(OCRMA)with different amount of crumb rubber was prepared to study the microscopic appearance of OCRMA by scanning electron microscope and fluorescence microscope and analyze the surface performance.The rheological properties and microscopic mechanism of OCRMA were characterized by dynamic shear rheological test,multiple stress creep recovery(MSCR)test,BBR test and infrared spectroscopy.The results show that the dissolution degree of waste crumb rubber is improved after WCO activation,and the compatibility with asphalt components is enhanced,and the stable cross-linking structure is formed,which improves the asphalt performance.The several new absorption peaks,which were obvious,were all caused by the composition of WCO,that is,there was no significant chemical change during the interaction between the activated crumb rubber and base asphalt.Compared with the common waste crumb rubber modified asphalt(CRMA),activation with WCO can significantly reduce the viscosity of CRMA,decrease the difference of segregation softening point by 27%,and enhance the low temperature performance by 30%.The aging degree is greatly reduced,and the anti-aging performance of OCRMA is increased by about 20%with the same dosage.The high temperature performance,though higher than that of base asphalt,decreases to some extent.After comprehensive analysis,the optimal dosage of crumb rubber for OCRMA is 30%.

Application and circular economy prospects of palm oil waste for eco-friendly asphalt pavement industry:A review

During the production of palm oil,a significant amount of waste is generated.However,because of inefficient handling and utilization,these wastes are becoming a larger issue.As a result,one initiative is to use these wastes in the pavement industry as sustainable materials.However,there is still a lack of understanding about the wider incorporation of palm oil waste in asphalt pavement and its performance.This study examines existing literature on the use of various wastes in the pavement industry,including palm oil clinker(POC),palm oil fibre(POF),palm kernel shell(PKS),and palm oil fuel ash(POFA).As a result,this paper presents a systematic review and scientometric investigation of related study publications on many uses of palm oil waste in the asphalt pavement industry and its performance from 2009 to 2022.The VOS viewer application was used to conduct the sciento-metric study analysis.The relationship between interactions detected in co-authored country studies cited sources of co-citation,and the keyword of the co-occurrence and publication source enabled the identification of the research gap.According to the systematic literature review,40%–60% POC can be used to fine aggregate for optimal performance,while 0–100%PKS can be used to replace coarse aggregate.In addition,50%–80% POFA or POC fine(POCF)can be used as a filler replacement,5%–8% POCF or POFA as a bitumen modifier,and 0.3% POF as a stabilizing additive.Furthermore,the study demonstrates that the safety of utilizing wastes with more than 50% CO_(2) emissions can be curtailed with minimal heavy metal leaching and radioactivity levels.The scientometric analysis may encourage researchers to seek out gaps in the literature that will aid in the long-term,multifaceted use of palm oil wastes in the asphalt pavement industry.Furthermore,the study recommends employing and researching the enormous potential of using palm oil waste in the pavement sectors because they are more sustainable and have better performance.However,there are some barriers to using palm oil waste in the asphalt pavement industry,such as a lack of design standards and guidelines,inefficient raw material pro-cessing conversion facilities,and large-scale production equipment.

Engine performance and combustion characteristics of a direct injection compression ignition engine fueled waste cooking oil synthetic diesel

Biodiesels produced from various feedstocks have been considered as alternative fuels used in internal combustion engines without major modifications.This research focuses on producing biodiesel from waste cooking oil(WCOSD)by the catalytic cracking method using MgO as the catalyst and comparing the engine operating characteristics of the test engine when using WCOSD and traditional diesel(CD)as test fuels.As a result,the brake power of the test engine fueled WCOSD,and traditional diesel is similar.However,the engine fuel consumption in the case of using WCOSD is slight increases in some operating conditions.Also,the nitrogen oxides emissions of the test engine fueled WCOSD are higher than those of CD at all tested conditions.The trend is opposite for hydrocarbon emission as the HC emission of the engine fueled by WCOSD reduces 26.3%on average.The smoke emission of the test engine in case of using WCOSD is lower 17%on average than that of CD.However,the carbon monoxide emissions are lower at the low and medium loads and higher at the full loads.These results show that the new biodiesel has the same characteristics as those of commercial biodiesel and can be used as fuel for diesel engines.

Optimization of Flow Parameters for Waste Lubricating Oil Combustion

The global energy demand has continued to skyrocket, exacerbating the already severe energy problem and environmental pollution, prompting researchers to look for alternative energy sources. Exploration of waste lubricating oil (WLO) as an alternative source of fuel has gained prominence among researchers due to its availability at low cost and the potential to generate energy while providing a safer means of disposal. The main challenge with WLO combustion is proper regulation of fuel and oxidizer during combustion to realize a near stoichiometric result. Additionally, WLO has high viscosity, hence preheating of the oil is necessary to lower the viscosity and enhance atomization, for a more efficient combustion process. This paper presents the optimization of flow parameters for combustion of WLO in a burner system by use of response surface methodology (RSM). The effects of air flow rate, injection pressure and fuel flow rate on combustion performance of a WLO burner were investigated. The highest flame temperature recorded was 1200°C at an air flow rate of 1 m3/min, fuel flow rate of 0.08 m3/hr and injection pressure of 20 bar. Tests on physical and chemical properties of WLO were conducted and characterized according to ASTM standard to ascertain its potential as an alternative fuel. The calorific values of WLO from petrol and diesel engines were found to be 41.23 MJ/kg and 42.65 MJ/kg respectively. Therefore, recycling of WLO by utilizing it as a fuel for burners has double benefits of mitigating environmental pollution and harnessing energy for process heating and power generation.

Combined Effect of a Catalytic Reduction Device with Waste Frying Oil-Based Biodiesel on NOx Emissions of Diesel Engines

Internal combustion engines with application in automobiles and other relevant industries constitute significant environmental pollution via the release of toxic exhaust gasses like carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), and nitrogen oxide (NOx). Engine researchers and manufacturers are challenged to develop external and internal measures to ensure environmentally friendly solutions to accommodate and conform to the growing list of emission standards. Therefore, this work presents an experimental investigation of the NOx emission profile of a diesel engine that is fuelled and fitted with waste frying oil-based biodiesel and catalytic converter. Using a single-cylinder, four-stroke air-cooled CI engine at a constant speed of 1900 rpm and different loadings of 25%, 50%, 75%, and 100%;fitted with a catalytic converter at the exhaust outlet of the engine and linked to a dynamometer and a gas analyser, an experiment was conducted at biodiesel/diesel volume blends of B0 (0/10), B5 (5/95), B20 (20/80), B30 (30/70), B70 (70/30), B100 (100/0);and 30% concentration (v/v), 0.5 litre/hr flow rate of aqueous urea from the catalytic converter. The results show an increasing NOx emission as the biodiesel component increased in the blend. The catalytic converter showed a downward NOx reduction with a significant 68% reduction in efficiency at high exhaust gas temperatures. It is concluded that the combined utilisation of waste frying oil-based biodiesel and the catalytic converter yields substantial NOx emission reduction.

A novel method for the green utilization of waste fried oil

Waste fried oil was studied to prepare three different types of detergent such as soap,liquid soap and soap powder via saponification process.The preparation conditions of soap base were optimized by orthogonal experiment.The specific preparation processes included waste fried oil treatment,orange peel extract preparation,saponification,demoulding and drying.Results showed that the optimal con-ditions for saponification were as follows:ratio of pure waste fried oil to coconut oil=6∶4,alkali liquor(NaOH)mass fraction 30%,saponification temperature 70℃,orange peel extract concentration 15%.The mature soap was then used to make liquid soap and soap powder by surfactant(sodium dodecylbenzene sulfonate,coconut diethanol amide)addition,followed by grinding.The prepared detergent conforms to the production standard of strong decontamination ability,possesses stable performance,is gentle to skin and non-toxic.

Efficient catalytic conversion of jatropha oil to high grade biofuel on Ni-Mo_(2)C/MCM-41 catalysts with tuned surface properties

The activity of Mo_(2) C-based catalyst on vegetable oil conversion into biofuel could be greatedly promoted by tuning the carbon content,while its modification mechanism on the surface properties remained elusive.Herein,the exposed active sites,the particle size and Lewis acid amount of Ni-Mo_(2) C/MCM-41 catalysts were regulated by varying CH_(4) content in carbonization gas.The activity of Ni-Mo_(2) C/MCM-41 catalysts in jatropha oil(JO)conversion showed a volcano-like trend over the catalysts with increasing CH_(4) content from 15%to 50%in the preparation process.The one prepared by 25%CH_(4) content(NiMo_(2) C(25)/MCM-41)exhibited the outstanding catalytic performance with 83.9 wt%biofuel yield and95.2%C_(15)-C_(18) selectivity.Such a variation of activity was ascribed to the most exposed active sites,the smallest particle size,and the lowest Lewis acid amount from Ni^(0) on the Ni-Mo_(2) C(25)/MCM-41 catalyst surface.Moreover,the Ni-Mo_(2) C(25)/MCM-41 catalyst could also effectively catalyze the conversion of crude waste cooking oil(WCO)into green diesel.This study offers an effective strategy to improve catalytic performance of molybdenum carbide catalyst on vegetable oil conversion.

Application of waste frying oils in the biosynthesis of biodemulsifier by a demulsifying strain Alcaligenes sp.S-XJ-1

Exploration of biodemulsifiers has become a new research aspect.Using waste frying oils（WFOs） as carbon source to synthesize biodemulsifiers has a potential prospect to decrease production cost and to improve the application of biodemulsifiers in the oilfield.In this study,a demulsifying strain,Alcaligenes sp.S-XJ-1,was investigated to synthesize a biodemulsifier using waste frying oils as carbon source.It was found that the increase of initial pH of culture medium could increase the biodemulsifier yield but decrease the demulsification ratio compared to that using paraffin as carbon source.In addition,a biodemulsifier produced by waste frying oils and paraffin as mixed carbon source had a lower demulsification capability compared with that produced by paraffin or waste frying oil as sole carbon source.Fed-batch fermentation of biodemulsifier using waste frying oils as supplementary carbon source was found to be a suitable method.Mechanism of waste frying oils utilization was studied by using tripalmitin,olein and tristearin as sole carbon sources to synthesize biodemulsifier.The results showed saturated long-chain fatty acid was diffcult for S-XJ-1 to utilize but could effectively enhance the demulsification ability of the produced biodemulsifier.Moreover,FT-IR result showed that the demulsification capability of biodemulsifiers was associated with the content of C=O group and nitrogen element.

Emissions of intermediate volatility organic compound from waste cooking oil biodiesel and marine gas oil on a ship auxiliary engine

Ship auxiliary engines contribute large amounts of air pollutants when at berth.Biodiesel,including that from waste cooking oil(WCO),can favor a reduction in the emission of primary pollutant when used with internal combustion engines.This study investigated the emissions of gaseous intermediate-volatile organic compounds(IVOCs)between WCO biodiesel and marine gas oil(MGO)to further understand the differences in secondary organic aerosol(SOA)production of exhausts.Results revealed that WCO exhaust exhibited similar IVOC composition and volatility distribution to MGO exhaust,despite the differences between fuel contents.While WCO biodiesel could reduce IVOC emissions by 50%as compared to MGO,and thus reduced the SOA production from IVOCs.The compositions and volatility distributions of exhaust IVOCs varied to those of their fuels,implying that fuel-component-based SOA predicting model should be used with more cautions when assessing SOA production of WCO and MGO exhausts.WCO biodiesel is a cleaner fuel comparing to conventional MGO on ship auxiliary engines with regard to the reductions in gaseous IVOC emissions and corresponding SOA productions.Although the tests were conducted on test bench,the results could be considered as representative due to the widely applications of the test engine and MGO fuel on real-world ships.

Metakaolinite as a catalyst for biodiesel production from waste cooking oil

The use of metakaolinite as a Catalyst in the transesterification reaction of waste cooking oil with methanol to obtain fatty acid methyl esters （biodiesel） was studied. Kaolinite was thermally activated by dehydroxylation to obtain the metakaolinite phase. Metakaolinite samples were characterized using X-ray diffraction, Nz adsorption-desorption, simultaneous thermogravimetric analyse/differential scanning calorimetry （TGA/DSC） experiments on the thermal decomposition of kaolinite and Fourier-transform infrared spectrometer （FTIR） analysis. Parameters related to the transesterificaion reaction, including temperature, time, the amount of catalyst and the molar ratio of waste cooking oil to methanol, were also investigated. The transesterification reaction produced biodiesel in a maximum yield of 95% under the following conditions： metakaolinite, 5 wt-% （relative to oil）; molar ratio of oil to methanol, 1：23; reaction temperature, 160℃; reaction time, 4 h. After eight consecutive reaction cycles, the metakaolinite can be recovered and reused after being washed and dried. The biodiesel thus obtained exhibited a viscosity of 5.4 mm2＂ s-1 and a density of 900.1 kg-m-3. The results showed that metakaolinite is a prominent, inexpensive, reusable and thermally stable catalyst for the transesterification of waste cooking oil.

Molecular dynamics simulation on the rejuvenation effects of waste cooking oil on aged asphalt binder

Waste cooking oil(WCO)has received attention on rejuvenating aged asphalt binder widely in recent years.This study evaluated the rejuvenation effects of WCO on aged asphalt binder on the micro-scale using molecular dynamics(MD)simulation.First,the representative molecules of WCO and asphalt binders were selected.The molecular mixture model was then developed.The thermodynamic properties were investigated,including density,cohesive energy density,solubility parameter,and surface free energy.The results show that WCO can restore the thermodynamic properties of aged asphalt binder to some extent and WCO has different influences on electrostatic interactions and van der Waals effects.From the diffusion behavior and molecular structure of asphalt binder,WCO can improve the molecular mobility and restore the colloidal structure.Besides,the adhesion work and moisture susceptibility of asphalt binder-aggregate interfaces(calcite and quartz)were evaluated.The results show that WCO can improve adhesion work between asphalt binder and aggregates since WCO can change molecular structure of asphalt binders and certain adhesion work exists between WCO and aggregates.Also,it can mitigate the moisture susceptibility of asphalt binder-aggregate interfaces(calcite and quartz).The study demonstrates that the MD simulation can help to understand the rejuvenation effects of WCO on aged asphalt binder on the micro-scale.

Biodiesel production from waste frying oil in sub- and supercritical methanol on a zeolite Y solid acid catalyst

Waste frying oil （WFO） is a very important feedstock for obtaining biodiesel at low cost and using WFO in transesterification reactions to produce biodiesel helps eliminate local environmental problems. In this study biodiesel was produced from WFO in sub- and super- critical methanol on a zeolite Y solid acid catalyst. The procedure was optimized using a design of experiments by varying the methanol to WFO molar ratio, the reaction temperature, and the amount of catalyst. Typical biodiesel yields varied from 83 to nearly 100% with methyl esters content ranging from 1.41-1.66mol.L-~ and typical dynamic viscosities of 22.1-8.2 cE Gas chromatography was used to determine the molecular composition of the biodiesel. The reaction products contained over 82 wt-% methyl esters, 4.2 wt-% free acids, 13.5 wt-% monoglycer- ides, and 0.3 wt-% diglycerides. The transesterification of WFO with methanol around its critical temperature combined with a zeolite Y as an acid catalyst is an efficient approach for the production of biodiesel with acceptable yields.

Study of engine performance, emission and combustion characteristics fueled with diesel-like fuel produced from waste engine oil and waste plastics

Utilizing oil extracted from waste engine oil and waste plastics, by pyrolysis, as a filel for internal combustion engines has been demonstrated to be one of the best available waste management methods. Separate blends of fuel from waste engine oil and waste plastic oil was prepared by mixing with diesel and experimental investigation is conducted to study engine performance, combustion and exhaust emissions. It is observed that carbon monoxide （CO） emission increases by 50% for 50% waste plastic oil （50WPO：50D） and by 58% for 50% waste engine oil （50WEO：50D） at full load as compared to diesel. Unburnt hydrocarbon （HC） emission increases by 16% for 50WPO：50D and by 32% for 50WEO：50D as compared to diesel at maximum load. Smoke is fotmd to decrease at all loading conditions for 50WPO：50D operation, but it is comparatively higher for 50WEO：50D operation. 50WPO：50D operation shows higher brake thermal efficiency for all loads as compared to 50WEO：50D and diesel fuel operation. Exhaust gas temperature is higher at all loads tbr 50WPO：50D and 50WEO：50D as compared to diesel fuel operation.

Impact of different nano additives on performance, combustion, emissions and exergetic analysis of a diesel engine using waste cooking oil biodiesel

Biodiesel is derived from waste cooking oil (WCO) by transesterification. Methylester was prepared by mixing diesel and biodiesel oils as 20% by volume. Nano particles asTiO2, Al2O3 and CNTs were blended with biodiesel blend at different concentrations of 25,50, and 100 mg/l to enhance the physicochemical fuel characteristics to obtain clean and effi-cient combustion performance. An experimental setup was incorporated into a diesel engine toinvestigate the influence of these nano-materials on engine performance, exergy analysis, combustion characteristics and emissions using WCO biodiesel-diesel mixture. Enriching methylester mixture with 100 ppm titanium, alumina and CNTs (B20T100, B20A100 andB20C100) increased the thermal efficiency by 4%, 6% and 11.5%, respectively compared toB20. Biodiesel blending with nano additives B20T100, B20A100 and B20C100 decreasedthe emissions of CO (11%, 24% and 30%, respectively), HC (8%, 17% and 25%, respectively)and smoke (10%, 13% and 19%, respectively) compared to B20. However, the noticeable increase of NOx was estimated by 5%, 12% and 27% for B20T100, B20A100 and B20C100,respectively. Finally, the results showed the rise in peak cylinder pressure by 5%, 9% and 11% and increase in heat release rate by 4%, 8% and 13% for B20T100, B20A100 andB20C100, respectively. The fuel exergy of B20T100, B20A100 and B20C100 are lower thanbiodiesel blend B20 by 6.5%, 16% and 23% but the exergetic efficiency are increased by 7%,19% and 30% at full load about B20.