2) Makale
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe Biogas Production from Organic Waste: Recent Progress and Perspectives(Springer, 2018-12-14) M.R., Atelge; David, Krisa; Gopalakrishnan, Kumar; Cigdem, Eskicioglu; Dinh Duc, Nguyen; Soon Woong, Chang; A. E., Atabani; Alaa H., Al‑Muhtaseb; S., UnalanAnaerobic digestion (AD) from organic waste has gained worldwide attention in reducing greenhouse gas emissions, lowering fossil fuel combustion, and facilitating a sustainable renewable energy supply. Biogas mainly consists of methane (CH4) (50–75%), carbon dioxide (CO2) (25–50%), hydrogen sulphides (H2S), hydrogen (H2), ammonia (NH3) (1–2%) and traces of other gases such as oxygen (O2) and nitrogen (N2). Methane can replace fossil fuels in various applications such as heat and power generation and the transportation sector. The degradation of organic waste through an AD process o?ers many advantages, such as the decrease of pathogens and prevention of odour release. The digestate from anaerobic fermentation is a valuable fertilizer, however, the amount of organic materials currently available for biogas production is still limited. New substrates, as well as more e?ective conversion technologies, are needed to grow this industry globally. This paper reviewed the latest trends and progress in biogas production technologies including potential feedstock. Recycling of waste has recently become an important topic and has been explored in this paper.Öğe Optimisation of sepiolite clay with phosphoric acid treatment as support material for CoB catalyst and application to produce hydrogen from the NaBH4 hydrolysis(Elsevier-Hydrogen energy, 2019) Selvitepe, Nuran; Balbay, Asım; Saka, CaferHerein, the CoB catalyst supported on the sepiolite clay treated with phosphoric acid was utilized to produce hydrogen from the NaBH4 hydrolysis. In order to analyse the performance of the phosphoric acid treated sepiolite clay supported-CoB catalyst, the NaBH4 concentration effect, phosphoric acid concentration effect, phosphoric acid impregnation time effect, CoB catalyst percentage effect, and temperature effect were studied. In addition, XRD, XPS, SEM, TEM, BET, and FTIR analysis were performed for characterization of CoeB catalyst supported on the acid-treated sepiolite. The completion time of this hydrolysis reaction with CoeB (20%) catalyst supported on the sepiolite treated by 5 M phosphoric acid was approximately 80 min, whereas the completion time of this hydrolysis reaction with acid-free sepiolite-supported CoeB (20%) catalyst was approximately 260 min. There is a five-fold increase in the maximum production rate. The maximum hydrogen production rates of this hydrolysis reaction at 30 and 60 C were found as 1486 and 5025 ml min 1g 1 catalyst, respectively. Activation energy was found as 21.4 kJ/mol. This result indicates that the acid treatment on sepiolite is quite successful. The re-usability of NaBH4 hydrolysis reaction by CoB catalyst supported on sepiolite treated phosphoric acid for successive five cycles of NaBH4 at 30 C was investigated.Öğe Fast and effective hydrogen production from ethanolysis and hydrolysis reactions of potassium borohydride using phosphoric acid(Elsevier-Hydrogen Energy, 2018-10-25) Saka, Cafer; Balbay, AsımThe hydrogen production from potassium borohydride (KBH4) with the ethanolysis and hydrolysis reactions using the phosphoric acid as a catalyst is performed for the first time. KBH4 concentration, phosphoric acid concentration and temperature effects were investigated for the optimum hydrogen production from ethanolysis and hydrolysis reactions of KBH4. The maximum hydrogen production rates in the ethanolysis and hydrolysis reactions with 1 M phosphoric acid are 6423 and 4296 ml min 1g 1, respectively. At the same time, the ethanolysis and hydrolysis reactions with the 1 M acid concentration were completed within 7 and 9 s, respectively. The total conversions obtained for the volume ratio of KBH4/acid of (1:1) were 100%. The power law kinetic model is performed for the kinetic studies. The activation energies for the ethanolysis and hydrolysis reactions of KBH4 using phosphoric acid are found as 2.98 and 2.60 kJ mol 1.Öğe Semi-methanolysis reaction of potassium borohydride with phosphoric acid for effective hydrogen production(Elsevier-Hydrogen Energy, 2018-11-15) Balbay, Asım; Saka, CaferThe methanol and water solvents were used for the production of hydrogen from potassium borohydride. In addition, phosphoric acid was selected as the green catalyst so that this semi-methanolysis reaction would be more effective for the first time. The semimethanolysis of potassium borohydride is investigated depend on potassium borohydride, phosphoric acid concentrations and temperatures. The maximum normalized hydrogen production rate obtained from this semi-methanolysis reaction with 1 M phosphoric acid as a catalyst was 5779 ml min 1 g 1. In addition, this semi-methanolysis reaction was completed in 5 s. Kinetic studies have been carried out with the power law kinetic model. The activation energy obtained for this semi-methanolysis reaction is 1.45 kJ mol 1.Öğe Efficient hydrogen production with controlled hydrochloric acid addition using Ni-based catalyst synthesized in ethanol solvent(Taylor Francis-Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019-04-03) Saka, Cafer; Balbay, AsımA Ni-based catalyst was synthesized in ethanol solvent by chemical reduction with sodium borohydride(NaBH4). This catalyst was used to catalyze the hydrolysis reaction of NaBH4 with hydrochloric acid (HCl) including different concentrations. Surface morphologies and characteristic properties of the Ni-based catalysts synthesized in the ethanol and water solvents were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), surface area measurements, and Fourier-transform infrared spectroscopy (FTIR) analyses, respectively. The maximum HGRs of the Ni-based (water) and Ni-based (ethanol) catalysts were 173 and 1054 ml g-1min-1, respectively. In addition, the HGR with 0.25 M HCl addition on the hydrolysis reaction using the Ni-based catalyst prepared in the ethanol solvent was about 1526 ml g-1min-1. Kinetic studies are performed according to the power law kinetic model. The activation energy (Ea) for the HG from the acidified hydrolysis reaction of NaBH4 using the Ni-based (ethanol) catalyst was found as 49 kJ mol-1.Öğe Influence of process parameters on enhanced hydrogen generation via semi-methanolysis and semi-ethanolysis reactions of sodium borohydride using phosphoric acid(Elsevier-Hydrogen Energy, 2019-10-16) Saka, Cafer; Balbay, AsımThe sodium borohydride(NaBH4) semi-methanolysis and semi-ethanolysis reactions to produce hydrogen are investigated using phosphoric acid(H3PO4) for the first time. The NaBH4 concentration, H3PO4 concentration, and temperature parameters on these semialcoholysis reactions are evaluated. The normalized hydrogen generation rates (HGRs) obtained from the NaBH4 semi-methanolysis and semi-ethanolysis acidified using 0.5 M H3PO4 are 11684 and 9981 ml min 1 g 1, respectively. Moreover, the completion times of these semi-methanolysis and semi-ethanolysis reactions with 0.5 M H3PO4 acid concentration are 0.10 and 0.116 min, respectively. Kinetic studies with the power-law model
