Unidad de deshidratación y unidad DOMGAS. Planta de licuación Gorgon LNG

In this Project, a preliminary design of a dehydration unit for domestic gas will be outlined. This unit that is the subject of the study belongs to a project named Gorgon. Such project is currently been developed by Chevron in Barrow Island, Australia. In order to conduct a proper design of such unit, characteristics of the natural gas that is being extracted shall be detailed, as well as proper specifications of the pipeline to which the gas will supply. After this, different techniques for dehydrating the gas are evaluated; the technique that fits better this Project is absorption by glycol and following such assumption will be chosen as the best one. More accurately, the most suitable type of glycol for this particular unit is triethilene glycol, considering that it fits better the conditions of the project. Once the method is chosen, a simulation shall be undertaken with the purpose of determining the number of stages required for the correct functioning of the unit, the glycol rate and its purity. Besides, it is needed to estimate its pressure and temperature and the dimensions that would then follow. In addition, pressures and temperatures are estimated at the regeneration glycol process, together with dimensions of some units. Furthermore, it is necessary to estimate pressure and temperature at which natural gas is leaving the dehydration unit. In addition, both compression needed to secure the flux at the pipeline and the resulting pressure at the reception shall be studied. Finally, an economic study is carried out in order to conclude whether or not this specific Project is feasible

New trends on photoelectrocatalysis (PEC):nanomaterials, wastewater treatment and hydrogen generation

The need for novel water treatment technologies has been recently recognised as concerning contaminants (organics and pathogens) are resilient to standard technologies. Advanced oxidation processes degrade organics and inactivate microorganisms via generated reactive oxygen species (ROS). Among them, heterogeneous photocatalysis may have reduced efficiency due to, fast electron-hole pair recombination in the photoexcited semiconductor and reduced effective surface area of immobilised photocatalysts. To overcome these, the process can be electrically assisted by using an external bias, an electrically conductive support for the photocatalyst connected to a counter electrode, this is known as photoelectrocatalysis (PEC). Compared to photocatalysis, PEC increases the efficiency of the generation of ROS due to the prevention of charge recombination between photogenerated electron-hole pairs thanks the electrical bias applied. This review presents recent trends, challenges, nanomaterials and different water applications of PEC (degradation of organic pollutants, disinfection and generation of hydrogen from wastewater)

Electrocatalytic reduction of CO2 in Deep Eutectic Solvents

Energy demand is constantly increasing and the use of fossil fuels causes an accumulation of carbon dioxide (CO2) which is an important environmental problem that needs to be solved. A promising solution to this problem would be the electrochemical reduction of CO2 to useful products, using the surplus of electricity from renewable sources. This would be a way of storing this excess of electricity in chemical bonds. However, this has not reached high efficiency and selectivity needed for establishing its use. For this process, the CO2 is usually dissolved in an aqueous electrolyte. This thesis proposes the new approach, using Deep Eutectic Solvents (DES) which would capture a higher concentration of CO2 helping to make the whole process more efficient. However, not all salt mixtures reach the eutectic point and therefore, the solvents formed are a low-transition temperature mixtures (LTTMs) of the selected salts.Experimental work was performed to find out if these solvents can be used for electrochemical carbon dioxide reduction. Non-reported LTTMs were synthetized; they were formed with mixtures of the hydrogen bond donor citric acid (CA), fructose (F) and diethanolamine (DEA) with the hydrogen bond acceptor tetrabutylammonium chloride (TBA-Cl) and different quantities of water, which was found necessary to carry out electrochemistry since the solvents formed were too viscous, and this water has an important effect in the electrocatalytic reduction of CO2 as proton source and charge carrier.These solvents were characterized electrochemically, performing studies to find out on which metallic surface they behave better (wider working potential window, low degree of decomposition and adsorption) and how different water quantities affect this process. These studies were performed using cyclic voltammetry. From this, it was seen that the solvents are more stable during electrochemical process in presence of copper. Moreover, the solvent formed by DEA:TBA-Cl:H2O in the molar proportions 1:1:1,375 was found to have interesting features that resemble CO2 reduction. As result, this solvent was further analysed using electrochemical in-situ Fourier-Transformed Infrared (FTIR) spectroscopy in surface-enhanced attenuated total reflectance configuration. With this, it was seen that the carbon dioxide was captured by the solvent and that there are visible changes when applying potential. Remarkably, the data shows the formation of a dimer OCCO on the Cu electrode surface, stabilized by the solvent. This project shows for the first time the electrochemical reduction of CO2 in LTTMs, evaluating different solvents, metals and water quantities. Determining that the carbon dioxide reduction is possible with the solvent DEA:TBA-Cl:H2O in the molar proportions 1:1:1,375 in a copper polycrystalline electrode. Electrical Engineering | Sustainable Energy Technolog

Solar photoelectrocatalytic oxidation of urea in water coupled to green hydrogen production

In past decades, the intensification of human activities has led to an increase in pollution and energy demand. Photoelectrochemical systems have emerged as an alternative for the decentralized management of domestic wastewater with the potential of recovering energy while degrading pollutants such as urea. Tungsten oxide (WO3) has been traditionally used for water splitting, but the use of this material for the removal of waste from water coupled to hydrogen production is not deeply known until now. This contribution shows an exhaustive and systematic investigation on WO3 photoanodes for the photoelectrochemical oxidation of urea and the generation of hydrogen, with insights on the reaction mechanism, detailed nitrogen balance investigation of the process, and analysis of the performance compared to well-accepted materials. The WO3 platelets were successfully synthesized in situ on fluorine doped tin oxide glass by a hydrothermal method. The performance of WO3 was compared to titanium dioxide (TiO2) as a benchmark. The photocurrent was enhanced for both electrodes when urea was added to the electrolyte, with WO3 showing one order of magnitude higher photocurrent than TiO2. The WO3 electrode showed a peak incident photon-to-current efficiency of 43% at 360 nm and a much greater rate constant for urea oxidation (1.47 × 10−2 min−1), compared to the TiO2 photoanode (16% at 340 nm and 1.1 × 10−3 min−1). The influence of different reactor configurations was also evaluated testing one- and two-compartment back-face irradiated photoelectrochemical cells. Hydrogen was generated with a Faradaic efficiency of 87.3% and a solar-to-hydrogen conversion efficiency of 1.1%. These findings aim to contribute to the development of technologies based on the photoelectrochemical production of hydrogen coupled with the oxidation of pollutants in wastewater

Dataset of paper "Solar photoelectrocatalytic oxidation of urea in water coupled to green hydrogen production"

Dataset of paper "Solar photoelectrocatalytic oxidation of urea in water coupled to green hydrogen production" Material characterization for TiO2 and WO3 electrodes. Photoelectrochemical characterization for TiO2 and WO3. One compartment cell characterization. Urea oxidation experiments for TiO2 and WO3 electrodes. Urea oxidation and products using one compartment cell. Production of NO2- during urea oxidation. Evolution of NO3− oxidation in time and conversion to NH4+. Two compartment cell characterization. Urea oxidation and products using two-compartment cell