Hydrogen Production

Bu çalışmada daha önceden deneysel olarak gerçekleştirilmiş olan biyokütle gazlaştırma süreci, Hesaplamalı Akışkanlar Dinamiği (HAD) ve Termodinamik Denge Yaklaşımı ile modellenmiş ve gaz ürün bileşimleri belirlenmiştir. Biyokütle olarak çalışmada pirinç kabuğu alınmıştır. Sıcaklık 750 – 900 C aralığında, ER değeri 0,3-0,45 aralığında ve S/B oranı 0,2-1,0 aralığında tutulmuştur. Sıcaklıktaki artış genel olarak H2 ve CO bileşimini artırırken CO2 bileşimini azaltmıştır. LHV değeri ise genel olarak sıcaklıkla artan bir davranış göstermiştir. ER değerindeki artış ise H2 ve CO ve CH4 bileşimi ile LHV değerini azaltmıştır. S/B oranındaki artış ise H2 , CO2 ve CH4 bileşimini artırırken CO bileşimi ve LHV değerini azaltmıştır. Tüm ürün bileşimi dikkate alındığında HAD yaklaşımının Termodinamik Denge Yaklaşımına kıyasla deneysel verilere daha yakın sonuç verdiği, Termodinamik Denge Yaklaşımının ise H2 ve CH4 bileşimi açısından iyi sonuç vermediği belirlenmiştir. Bu sonuçlar sonucunda HAD ya...

Photocatalytic water splitting is considered one of the most important and appealing approaches for the production of green H2 to address the global energy demand. The utmost possible form of artificial photosynthesis is a two‐step photoexcitation known as “Z‐scheme”, which mimics the natural photosystem. This process solely relies on the effective coupling and suitable band positions of semiconductors (SCs) and redox mediators for the purpose to catalyze the surface chemical reactions and significantly deter the backward reaction. In recent years, the Z‐scheme strategies and their key role have been studied progressively through experimental approaches. In addition, theoretical studies based on density functional theory have provided detailed insight into the mechanistic aspects of some breathtakingly complex problems associated with hydrogen evolution reaction and oxygen evolution reaction. In this context, this critical review gives an overview of the fundamentals of Z‐scheme pho...

Este manuscrito reúne conceitos fundamentais de Física, Físico-Química e Termodinâmica (Primeira Lei) que são apresentados aos alunos da UNESA na disciplina Física II, a qual faz parte da grade curricular dos cursos de Engenharia Civil e Engenharia Ambiental e Sanitária. Procuramos focar em conceitos e exercícios chaves, de forma a apresentar o conteúdo com a maior clareza possível. Assim, seguindo as estrofes da música "Comida" (Titãs, 1987) - "A gente não quer só comida. A gente quer comida, diversão e arte." - enfatizamos as noções de calor, trabalho, energia e as correlações.

The present work is the first investigation of the electrocatalytic performances of ZrP2O7 as a cathode in a single-chamber Microbial Fuel Cell (MFC) for the conversion of chemical energy from wastewater to bioelectricity. This catalyst was prepared by a coprecipitation method, then characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), ultraviolet–visible–near-infrared spectrophotometry (UV–Vis–NIR), and cyclic voltammetry analyses. The acid–basic characteristics of the surface were probed by using 2-butanol decomposition. The conversion of 2-butanol occurs essentially through the dehydrating reaction, indicating the predominantly acidic character of the solid. The electrochemical test shows that the studied cathode material is electroactive. In addition, the ZrP2O7 in the MFC configuration exhibited high performance in terms of bioelectricity generation, giving a...

Energy Crisis is one of the major issues of Pakistan. There are many reasons of deficit in demand and supply energy such as fuel cost, inefficient power plants and non-utilization of indigenous resources. Most of the public sector thermal power plants (GENCOs) currently operating in the country are not more than 30% efficient, which reduces the output power drastically and result in high tariff rates. In this scenario, the installation of efficient power plants has a high potential to overcome the energy crisis significantly. Magneto Hydro Dynamic (MHD) has the capability to increase the efficiency of existing power plants and utilization of vast coal reserves with negligible effects of environmental pollution. Generators In this paper the review of MHD generating technology is presented and the current research including a number of innovative MHD cycles are discussed. The prospects of this technology are explored in generation sector of Pakistan as a solution to energy crisis and ...

The aim of this study was comparative analysis of catalysts with 5 and 20 wt. % Ni loading, with and without Pd additive, and it included: determination of reduction degrees, investigation on microstructure by scanning electron microscopy and chemical analysis by energy-dispersive spectroscopy. Ni/Al2O3 and Ni-Pd/Al2O3 catalysts supported on ?-Al2O3-based foams were synthesized by aerosol assisted impregnation. Impregnation of the foams by ultrasonically aerosolized chlorides was followed by drying at 473 K and hydrogen reduction at 533 and 633 K. Lower Ni loading resulted in higher reduction degrees. Ni loading of 20 wt. % enabled relatively uniform coverage of the foam with a metallic coating. With activity modifier (Pd), nearly complete reduction was achieved at both temperatures. Reduction degrees reached 99.4 and 98.2 wt. % at 533 K for 5 and 20 wt. % of Ni, respectively.

This study presents the use of a machine learning method from the artificial intelligence area, such as the support vector machines, applied to the construction of data-based classification models for diagnosing undesired scenarios in the hydrogen production process by photo-fermentation, which was carried out by an immobilized photo-bacteria consortium. The diagnosis models were constructed with data obtained from simulations run with a mechanistic model of the process and assessed on both modelled and experimental batches. The results revealed a 100% diagnosis performance in those batches where light intensity was below and above an optimum operation range. Nevertheless, 55% diagnosis performance was obtained in modelled batches where pH was away from its optimum operation range, showing that diagnosis model predictions during the first observations of those batches were classified as normal operation and revealing diagnosis delay in pH oscillations. In general, results demonstrat...