Catalytic pyrolysis of olive cake and domestic waste for biofuel production

The development of waste-to-energy technologies provides an integrated approach to waste management, climate protection, and sustainable devolvement. In this study, biofuels were produced from “olive cake” combined with used paper and scrap tire. A lab-scale facility was designed to carry out catalytic pyrolysis of a solid feedstock comprising 5 wt% used paper, 5 wt% scrap tire, and 90 wt% olive cake. Jordanian volcanic tuff was used as a catalyst during pyrolysis. The catalytic pyrolysis produced various proportions of gaseous, liquid, and solid biofuels. The use of catalyst influenced the composition, quality, and yield of products via cracking and reforming reactions.     

Bio‐oil production from rapid pyrolysis of cottonseed cake: product yields and compositions

Fixed‐bed fast pyrolysis experiments have been conducted on a sample of cottonseed cake to determine the effects of pyrolysis temperature, heating rate and sweep gas flow rate on pyrolysis yields and chemical compositions of the product oil. The liquid products and the subfractions of pentane soluble part were characterized by elemental analysis, FT‐IR spectroscopy, ¹H‐NMR spectroscopy and pentane subfraction was analysed by gas chromatography. The maximum oil yield of 34.8% was obtained at final temperature of 550°C with a heating rate of 700°C min^?1 and nitrogen flow rate of 100 cm³ min^?1. Chromatographic and spectroscopic studies on bio‐oil have shown that the oils obtained from cottonseed cake can be used as a renewable fuel and chemical feedstock. Copyright © 2005 John Wiley & Sons, Ltd.     

Slow catalytic pyrolysis of rapeseed cake: Product yield and characterization of the pyrolysis liquid

The performance of three catalysts during slow catalytic pyrolysis of rapeseed cake from 150 to 550 °C over a time period of 20 min followed by an isothermal period of 30 min at 550 °C was investigated. Na₂CO₃ was premixed with the rapeseed cake, while γ-Al₂O₃ and HZSM-5 were tested without direct biomass contact. Catalytic experiments resulted in lower liquid and higher gas yields. The total amount of organic compounds in the pyrolysis liquid was considerably reduced by the use of a catalyst and decreased in the following order: non-catalytic test (34.06 wt%) > Na₂CO₃ (27.10 wt%) > HZSM-5 (26.43 wt%) > γ-Al₂O₃ (21.64 wt%). In contrast, the total amount of water was found to increase for the catalytic experiments, indicating that dehydration reactions became more pronounced in presence of a catalyst. All pyrolysis liquids spontaneously separated into two fractions: an oil fraction and aqueous fraction. Catalysts strongly affected the composition and physical properties of the oil fraction of the pyrolysis liquid, making it promising as renewable fuel or fuel additive. Fatty acids, produced by thermal decomposition of the biomass triglycerides, were converted into compounds of several chemical classes (such as nitriles, aromatics and aliphatic hydrocarbons), depending on the type of catalyst. The oil fraction of the pyrolysis liquid with the highest calorific value (36.8 MJ/kg) was obtained for Na₂CO₃, while the highest degree of deoxygenation (14.0 wt%) was found for HZSM-5. The aqueous fraction of the pyrolysis liquid had opportunities as source of added-value chemicals.     

Thermophysical and optical properties of NiCo2O4@ZrO2: A potential composite for thermochemical processes

The use of solar energy through thermochemical processes is an important approach to drive endothermic reactions to produce solar fuels such as hydrogen or syngas. This work reports the preparation and the thermophysical characterization of a porous composite based on zirconium dioxide (ZrO₂) and nickel cobaltite (NiCo₂O₄) nanoparticles for applications in thermochemical processes at high temperatures. The ZrO₂ supports were modified with NiCo₂O₄ nanoparticles by a low-cost and straightforward impregnation process following by thermal treatment at 773 K. The impregnated NiCo₂O₄ obtained is formed by nanoparticles with an average size of 50 nm favoring a complete and homogenous covering of ZrO₂ supports. The thermal properties of ZrO₂ supports and NiCo₂O₄@ZrO₂ composites were evaluated in the temperature range from 300 to 1250 K. Besides, the solar absorbance and thermal emittance values were measured. After depositing the nickel cobaltite nanoparticles in the supports, it has been observed that the thermal properties have changed slightly so that the added nanoparticles do not significantly change the thermal performance of the materials. The nickel cobaltite nanoparticles deposited on the surface of the ZrO₂ supports causes a strong increase in solar absorbance. This improves the efficiency of solar thermal conversion. Our results have shown that NiCo₂O₄@ZrO₂ has excellent characteristics to be used in solar thermochemical processes.     

An experimental study for a combined system of tar sand, oil shale, and olive cake as a potential energy source in Jordan

Jordan is an example of a third world country that is non-oil producing but contains huge reserves of other energy sources such as tar sand, oil shale, and olive cake. Some limited research is available about how to utilize these energy sources in pure form. However, available research does not deal with combinations of these energy sources. This experimental study investigates combinations of these energy forms as potential energy sources in Jordan. The experimental procedure involves characterization of samples by proximate analysis, calorific value determination of different combinations, and a compacting process of the different particles. The best combination, with respect to calorific value, is found to be 20% tar sand, 20% olive cake, and 60% oil shale. Compacting materials either with starch or with heated tar sand up to 110°C for 1 h indicates a feasible process for handling, packaging, and transporting.     

Harvesting operations and energetics of tall grasses for biomass energy production: A case study

The U.S.A. imports about 50% of its energy needs while Florida imports about 85%. Among the renewable energy sources available, biomass appears promising especially in the southeast which includes Florida because of a favorable environment for production and the available methods to convert biomass to energy. Optimal production of biomass requires the identification and management of high yielding persistent perennial cultivars. Elephantgrass (Pennisetum purpureum Schum.) and energycane (Saccharum spontaneum L.) are two tall grasses that meet these requirements. To optimize the supply of convertible biomass, suitable methods of harvesting the crop must be available. The purpose of this research was to study the feasibility and energetics of harvesting, drying, and baling tall grasses with conventional farm machinery.

A Mathews rotary scythe and a New Holland 849 Auto Wrap large round baler were determined to provide a practical harvesting system for baled biomass averaging 15–27 Mg ha⁻¹. The rotary scythe can be used for harvesting and fluffing or turning a windrow over to expedite drying. This harvesting system requires about 3 kg diesel fuel Mg⁻¹ dry biomass (DB), 25 min of time Mg⁻¹ DB, and a cost of about $10 to 12 Mg⁻¹ DB. Energy requirements of harvesting operations would be about 300–375 MJ Mg⁻¹ DB, and primary energy requirements for production and harvesting are about 1100–1500 MJ Mg⁻¹ DB. For each unit of fossil fuel invested in the total production and harvesting system, 12–15 units would be returned in biomass.     

Perspective and potential of CO2: A focus on potentials for renewable energy conversion in the Mediterranean basin

Figures commonly quoted on the soon shortage of generating energy from fossil sources which may give the impression that it will be possible to switch to renewable energies conversion as foundations for the future of industrial instances in the Mediterranean basin. In this study, CO₂ energy potential and perspectives in the Mediterranean basin have been investigated in terms of efficiency, feasibility, geographical patterns and savings. Two conjoint mathematical protocols have been carried out in order to yield a simplified extracted scheme for prototype CO₂ trapping/storage plants.     

Black cobalt coatings for photothermal conversion of solar energy: Preparation and characterization

This paper presents an investigation on the optical and physical properties of spectrally selective solar absorbing coatings of black cobalt prepared by spray pyrolysis technique onto chemically brightened aluminium substrates. Advantages are low cost, reasonably good selectivity and can be scaled on collectors of any desired size. The coatings exhibit high absorptivity. $\text{α ? 0.93}$ in the “Solar” range and low emissivity, $\text{?(100°}\text{C}\text{) ? 0.22}$ in the “Thermal” range. The photothermal conversion efficiencies of black paint coated and black cobalt coated solar collectors are compared.     

Use of tergitol-7 in photogalvanic cell for solar energy conversion and storage: Toluidine blue-glucose system

Photogalvanic effects were studied in a photogalvanic cell containing toluidine blue, glucose and tergitol-7 as a photosensitizer, reductant and surfactant, respectively. The photocurrent and photopotential generated by this system were 70 μA and 315 mV, respectively. The effects of different parameters on the electrical output of the cell were observed. Current/voltage characteristics of the cell have also been studied, and a mechanism has been proposed for the generation of photocurrent in photogalvanic cell.     

Optimization of an energy district for fuel cell electric vehicles: Cost scenarios of a real case study on a waste and recycling fleet

This paper analyses the planning and operation of an energy district that aims to integrate a hydrogen supply chain for feeding vehicles based on fuel cell technology. A model of an energy district and an optimization algorithm based on the economic parameters are presented and validated leveraging an existing energy district, simulating several scenarios depending on different economic conditions and technical parameters. The model of the energy district evaluates energy balances, distinguishing hydrogen and electrical energy flows; the districts can include an FCEV fleet, electrical loads, energy generators, storage system and an electrolyser for producing hydrogen from the green energy surplus produced in the district as well as drawing energy from the power distribution network. The algorithm, based on MILP, is used for optimizing the flows in the district; indeed, it evaluates all the technical and economic constraints at a certain timestamp and provides optimal scheduling of the energy units. Model and algorithm have been used to evaluate different scenarios that were identified by varying the economic parameters (i.e., prices of electrical energy and hydrogen) as well as district design (i.e., upgrading sizes of the generators and electrolysers). Energy district parameters have been identified exploiting real data collected in an existing district located in Terni (Italy) owned by the local multi-utility ASM Terni S.p.A. It already includes a fleet for waste management, PV plants, office buildings and warehouses. Through parameters combination, 1125 OPEX and 729 CAPEX simulated scenarios have been evaluated and reported; each scenario assesses the daily variation of variables' economic trends covering the timeframe from 2030 to 2050. Results of simulations highlight the most convenient economic contexts as well as the envisioned amount of expenditures for adopting FCEV in the presented district or similar ones. For the case study, the forecasted cost of the hydrogen district, including FCEVs, is fully comparable to current costs, resulting in some cases even cheaper.     

Thermocatalytic decomposition of methane for hydrogen production using activated carbon catalyst: Regeneration and characterization studies

A series of experiments was conducted to study the deactivation and regeneration of activated carbon catalyst used for methane thermocatalytic decomposition to produce hydrogen. The catalyst becomes deactivated due to carbon deposition and six decomposition cycles of methane at temperatures of 850 and 950 °C, and five cycles of regeneration by using CO₂ at temperatures of 900, 950 and 1000 °C were carried out to evaluate the stability of the catalyst. The experiment was conducted by using a thermobalance by monitoring the mass gain during decomposition or the mass lost during the regeneration with time. The initial activity and the ultimate mass gain of the catalyst decreased after each regeneration cycle at both reaction temperatures of 850 and 950 °C, but the amount is smaller under the more severe regenerating conditions. For the reaction at 950 °C, comparison between the first and sixth reaction cycles shows that the initial activity decreased by 69, 51 and 42%, while the ultimate mass gain decreased by 62%, 36% and 16% when CO₂ gasification carried out at 900, 950 and 1000 °C respectively. Temperature -programmed oxidation profiles for the deactivated catalyst at reaction temperature of 950 °C and after several cycles showed two peaks which are attributed to different carbon characteristics, while one peak was obtained when the experiment was carried out at 850 °C. In conclusion, conducting methane decomposition at 950 °C and regeneration at 1000 °C showed the lowest decrease in the mass gain with reaction cycles.     

Conversion of individual natural gas to district heating: Geographical studies of supply costs and consequences for the Danish energy system

Replacing individual natural gas heating with district heating based to increasing shares of renewable energy sources may further reduce CO₂-emissions in the Danish Building mass, while increasing flexibility of the energy system to accommodate significantly larger amounts of variable renewable energy production. The present paper describes a geographical study of the potential to expand district heating into areas supplied with natural gas. The study uses a highly detailed spatial database of the built environment, its current and potential future energy demand, its supply technologies and its location relative to energy infrastructure. First, using a spatially explicit economic model, the study calculates the potentials and costs of connection to expanded district heating networks by supply technology. Then a comprehensive energy systems analysis is carried out to model how the new district heat can be supplied from an energy system with higher shares of renewable energy. It can be concluded on the basis of these analyses that the methods used proved highly useful to address issues of geographically dependent energy supply; however the spatio-economic model still is rather crude. The analyses suggest to expand district heating from present 46% to somewhere in between 50% and 70%. The most attractive potential is located around towns and cities. The study also suggests that CO₂-emissions, fuel consumption and socio-economic costs can be reduced by expanding district heating, while at the same time investing in energy savings in the building mass as well as increased district heating network efficiency.     

Study the performance of photogalvanic cells for solar energy conversion and storage: Toluidine blue–D‐Xylose–NaLS system

Toluidine blue has been used as the photosensitizer with D ‐Xylose as the reductant and s odium lauryl sulphate as the surfactant for the enhancement of the conversion efficiency and storage capacity along with reduction in cost of the photogalvanic cell for its commercial viability. The observed value of open circuit voltage is 1110.0 mV and the photogeneration of photopotential is 945.0 mV, whereas the maximum photocurrent is 510.0 µA and the short circuit current or photocurrent at equilibrium is 430.0 µA. The rate of initial generation of photocurrent is 56.66 µA min^?1. The determined maximum power and power at power point are 406.35 µW and 148.96 µW, respectively. The observed conversion efficiency is 1.4323%. The fill factor 0.3120 has been experimentally determined at the power point of the cell, where the absolute value is 1.0. The photogalvanic cell so developed can work for 130.0 min in dark if it is irradiated for 145.0 min, i.e. storage capacity of the photogalvanic cell is 89.65%. A mechanism has also been proposed for the photogeneration of the photocurrent. Copyright © 2010 John Wiley & Sons, Ltd.     

Facile synthesis and characterization of Sc2O3 nanoparticles for electrocatalytic oxidation of ethanol: Cyclic voltammetry and chronoamperometry studies

In this research, scandium oxide, Sc₂O₃, nanoparticles (Sc₂O₃NPs) were synthesized via a facile and simple sol-gel auto-combustion process with olive oil as capping agent. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–visible diffuse reflectance spectra (UV-DRS) were used to characterize the particle size, morphology and optical properties of the calcined powders. The XRD patterns showed that Sc₂O₃ nanoparticles have cubic structure with particle size about 8 nm. UV–vis spectroscopy showed a strong sharp absorption peak around 315 nm, attributed to the O_2p → Sc_3d charge-transfer interaction. In the next step, Sc₂O₃NPs were used for modification of carbon paste electrode (CPE) surface. Then, the electrocatalytic properties of the Sc₂O₃NPs/CPE towards ethanol oxidation were compared with the CPE. The results showed the electrocatalytic performance of the Sc₂O₃NPs/CPE is higher than the unmodified CPE. Also, chronoamperometry studies showed that Sc₂O₃/CPE has long-term stability against the poisoning species, as compared with the CPE. Therefore, Sc₂O₃ catalyst is proposed as an efficient anodic electrode for use in direct ethanol fuel cells in acidic media.