Cerium-Promoted Nickel /Alumina Catalyst for Producer Gas Reforming and Tar Conversion

The catalytic conversion of a model tar compound, namely: naphthalene contained in a simulated producer gas from wood gasification process was investigated. The sol-gel approach was used to create a mesoporous Cepromoted Ni/alumina catalyst with high surface area. A surface area of 333 m2g was achieved by calcination of the mesoporous catalyst (17 wt% Ni and 2.8 wt% Ce) under air conditions at 1123 K. The catalysts were characterized using the N2 adsorption-desorption, XRD, and SEM techniques, and their promotion effect on producer gas reforming and tar removal was studied under dry, steam, and partial oxidation conditions. The Ni-based catalysts effectively converted naphthalene and increased the proportion of H2 and CO in the reformed gas. Incorporating Ce into the catalyst increased the proportion of H2 and CO in the reformed gas, while lowering the amount of CH4 and CO2. In the absence of oxygen, catalytic reforming of the producer gas resulted in 79.6% naphthalene conversion, whereas catalytic partial oxidation conditions resulted in 99.1% naphthalene conversion

Performance of chemically modified Tripoli in catalytic pyrolysis of date kernels

The use of natural minerals as catalysts in pyrolysis enhances the products’ yield and quality. However, natural minerals may lack the proper active sites to effectively catalyze the pyrolytic reactions. This paper addresses the performance of iron-chemically modified Jordanian Tripoli catalysts in the catalytic pyrolysis of date kernels. The Fe-chemically modified Tripoli catalyst was prepared by impregnation method at three different loadings (0.046, 1.788, 3.530 wt %). The effect of three different process variables, namely: pyrolysis temperature, heating rate and iron-loading on the performance of date kernels pyrolysis were investigated. Full factorial design methodology is employed to study the main effects of process variables and possible interaction effects among the process variables on the yields of the catalytic pyrolysis products. The maximum gas yield (197.8 ml/g-feed) was obtained at a pyrolysis temperature of 600 °C, heating rate of 20 °C/min and 3.530 wt% Fe-loading. The maximum bio-oil yield (42.88 wt%) was obtained at a pyrolysis temperature of 500 °C, heating rate of 60 °C/min and 1.788 wt% Fe-loading. The maximum bio-char yield (38.72 wt%) was obtained at a pyrolysis temperature of 400 °C, heating rate of 20 °C/min and catalytic pyrolysis using natural Tripoli. First order egression models are proposed to predict the product yields. The main implication of this study is that Fe-loaded Tripoli has effectively enhanced the quality of bio-oil

Pyrolysis of Domestic Sewage Sludge: Effect of Process Parameters on Biochar Calorific Value

This research aims to look into a sustainable technique for the treatment, reuse and disposal of domestic sewage sludge (DSS). The purpose of the study was to examine the operating factors that influence the calorific value of the produced biochar from the pyrolysis of DSS. Based on the analysis of the full factorial design, the impacts of the pyrolysis conditions, specifically: temperature, heating rate, and isothermal time on the calorific value of biochar were evaluated. When the pyrolysis temperature was raised from 300 to 500 oC, the calorific value of biochar was decreased by 34%. A 14% decrease in the calorific content of the biochar was also noticed when the heating rate was increased from 5 to 35 oC/min. When the isothermal time was increased from 45 to 120 minutes, the calorific value of the biochar remained essentially unchanged. No interaction effects among process variables were found using the factorial design methodology. A first-order regression model was developed to predict the calorific value of biochar using the magnitude of the effects of the process factors and their interactions. The model predictions agreed very well with the obtained experimental results

Phosphate removal from aqueous solutions by using natural Jordanian zeolitic tuff

In this study, a naturally occurring zeolitic tuff located in Jordan was investigated as a potential adsorbent for phosphate removal from aqueous solution. Adsorption kinetics and thermodynamics of phosphate adsorption under different temperatures were studied. The pseudo-second-order kinetic model adequately fitted the collected experimental data under different initial ion concentrations. The Langmuir model is found to be successfully fitting the experimental data. Thermodynamic parameters such as Gibbs's free energy change, standard enthalpy change, and entropy change were evaluated and the results indicated that the sorption process is spontaneous, exothermic with small degree of randomness during the sorption process

A Techno-Economic Analysis of Sustainable Material Recovery Facilities: The Case of Al-Karak Solid Waste Sorting Plant, Jordan

Solid waste sorting facilities are constructed and operated to properly manage solid waste for both material and energy recovery. This paper investigates the possible technical and economic performance of the Al-Karak solid waste sorting plant in order to achieve financial sustainability and increase the profits that return on the plant to cover its operating costs. A standard procedure was followed to quantify and characterize the input materials of commercial solid waste by determining the recyclable materials in the sorting products. Thus, possible different equipment and material flows through the plant were proposed. An economic model was used in order to know the feasibility of the proposed options of the plant according to three economic factors, which are net present worth (NPW), return on investment (ROI), and payback period values. The results inferred that the characterization of the input materials contains a high portion of recyclable materials of paper, cardboard, plastic, and metals, which accounted for 63%. In this case, the mass of rejected waste to be landfilled was 9%. Results for the proposed options showed that the economic analysis is feasible when working loads on three and two shifts with ROI values of 4.4 and 3.5 with a payback period of the initial cost in 2 and 3 years, respectively. Working load on one shift was not feasible, which resulted in an ROI value of less than 2 and a payback period larger than 5 years. This paper recommended operating the sorting plant at a higher input feed with a working load on three shifts daily to ensure a maximum profit and to reduce the amount of commercial solid waste prior to landfilling through the concept of sorting and recycling

A Techno-Economic Analysis of Sustainable Material Recovery Facilities: The Case of Al-Karak Solid Waste Sorting Plant, Jordan

Solid waste sorting facilities are constructed and operated to properly manage solid waste for both material and energy recovery. This paper investigates the possible technical and economic performance of the Al-Karak solid waste sorting plant in order to achieve financial sustainability and increase the profits that return on the plant to cover its operating costs. A standard procedure was followed to quantify and characterize the input materials of commercial solid waste by determining the recyclable materials in the sorting products. Thus, possible different equipment and material flows through the plant were proposed. An economic model was used in order to know the feasibility of the proposed options of the plant according to three economic factors, which are net present worth (NPW), return on investment (ROI), and payback period values. The results inferred that the characterization of the input materials contains a high portion of recyclable materials of paper, cardboard, plastic, and metals, which accounted for 63%. In this case, the mass of rejected waste to be landfilled was 9%. Results for the proposed options showed that the economic analysis is feasible when working loads on three and two shifts with ROI values of 4.4 and 3.5 with a payback period of the initial cost in 2 and 3 years, respectively. Working load on one shift was not feasible, which resulted in an ROI value of less than 2 and a payback period larger than 5 years. This paper recommended operating the sorting plant at a higher input feed with a working load on three shifts daily to ensure a maximum profit and to reduce the amount of commercial solid waste prior to landfilling through the concept of sorting and recycling

Anaerobic Co-Digestion of Domestic Sewage Sludge with Food Waste: Incorporating Food Waste as a Co-Substrate Under Semi-Continuous Operation

Anaerobic co-digestion of domestic sewage sludge with food waste as a substrate for biogas production and as a mean for waste management was conducted. The food waste was incorporated into the bioreactor as a cosubstrate semi-continuously via replacement mode and addition mode of operations in ratios up to 50%. The methane gas yield under the replacement mode of operation ranged from 295 to 1358 ml/gVSadded and from 192 to 462 ml/gVSadded for the replacement mode of operation and the addition mode of operation, respectively. The results indicate that the methane gas yield increases along with the percentage share of food waste in the feed. Anaerobic co-digestion under semi-continuous operation enabled handling large organic loadings compared to batch co-digestion processes

Growth Kinetics and Toxicity of Pseudomonas fredriksbergsis Grown on Phenol as Sole Carbon Source

Phenol is one of the main pollutants that have a serious impact on the environment and can even be very critical to human health. The biodegradation of phenol can be considered an increasingly important pollution control process. In this study, the degradation of phenol by Pseudomonas fredriksbergsis was investigated for the first time under different growth conditions. Six different initial concentrations of phenol were used as the primary substrate. Culture conditions had an important effect on these cells' ability to biodegrade phenol. The best growth of this organism and its highest biodegradation level of phenol were noticed at pH 7, temperature 28 °C, and periods of 36 and 96 h, respectively. The highest biodegradation rate was perceived at 700 mg/L initial phenol concentration. Approximately 90% of the phenol (700 mg/L) was removed in less than 96 hours of incubation time. It was found that the Haldane model best fitted the relationship between the specific growth rate and the initial phenol concentration, whereas the phenol biodegradation profiles time could be adequately described by the modified Gompertz model. The parameters of the Haldane equation are: $0.062 h^{−1}$, 11 ppm, and 121 ppm for Haldane’s maximum specific growth rate, the half-saturation coefficient, and the Haldane’s growth kinetics inhibition coefficient, respectively. The Haldane equation fitted the experimental data by minimizing the sum of squared error (SSR) to $1.36×10^{-3}$