Comparative Analysis of Zeolite Y From Nigerian Clay and Standard Grade

Zeolite Y catalyst with silica/alumina mola•· ntio of 4.70 was synthesized from Elefun (Nigel"ia) clay unde•· hydwthe•·mal tJ·eatment of calcined kaolin with aqueous NaOH at atmosphel"ic p•·essm·e. This pape•· descl"ibed the p•·epantion of zeolite Y catalyst fmm metakaolin of quality Elefun kaolin by ageing at 34oC fo•· 7days, and then n·ystallized at lOOoC fm· 24 hom·s. The synthesized zeolite NaY was modified by exchanging with NH4Cl to obtain its hydwgen fo•·m with silica/alumina ntio of 3.18. Both developed and standa1·d zeolite Y catalyst we1·e then chanctel"ized by a val"iety of physicochemical methods, including XRD, XRF spectwscope. The mm·phologies we1·e examined using SEM. Similar results we1·e obtained, thus confi•·ming the synthesis of zeolite Y

Flow Measurement of CO2 in a Binary Gaseous Mixture Using an Averaging Pitot Tube and Coriolis Mass Flowmeters

To combat the growing emissions of CO2 from industrial processes, Carbon Capture and Storage (CCS) and Carbon Capture and Utilization technologies (CCU) have been accepted worldwide to address these pressing concerns. So as to efficiently manage material and financial losses across the entire stream, accurate accounting and monitoring through fiscal metering of CO2 in CCS transportation pipelines are core and required features for the CCS technologies. Moreover, these technical requirements are part of the legal compliance schemes and guidelines from various regulatory bodies. The CO2 transportation pipelines will likely have multiple inputs from different capture plants, each with varying composition of CO2 and thus introducing impurities into the CO2 stream. The presence of other ordinary or hydrocarbon gases in the CO2 gas stream could affect the functionality of metering instruments by introducing additional errors, particularly in the case of volumetric flowmeters. In this study, volumetric and direct mass measurement methods for the flow measurement of CO2 mixtures using two totally different metering principles are experimentally evaluated. An Averaging Pitot Tube with Flow Conditioning Wing (APT-FCW) and Coriolis mass flowmeters (CMF) are used to assess the flow metering of CO2 in a binary gaseous mixture. Different gases (nitrogen, air, oxygen, argon and propane) are diluted as contaminants into the pure CO2 gas flow for various mass fractions to produce an adulterated mixture of the CO2 gas. Comparative analysis of the measurement results under these flow conditions relative to that of pure CO2 gas show that the measurement error of the APT-FCW sensor increases with the mass fraction of the diluent component, and gases with density closer to that of CO2 have a much lesser effect on the performance of the APT-FCW flow sensor for smaller mass fractions. The CMF proved to be very reliable in the gas combination processes and as a reference meter for the APT-FCW sensor. Further analytical observations are discussed in detail

Exergy, Exergoeconomic and Exergoenvironomic Analyses of Selected Gas Turbine Power Plants in Nigeria.

Energy supply trends as well as environmental regulations and climate change issues have made it necessary to closely scrutinize the way energy is utilized. Efficient energy utilization thus requires paying more attention to accurate and advanced thermodynamic analysis of thermal systems. Hence, methods aimed at evaluating the performances of energy systems take into account the Energy, Environment and Economics. Therefore, the first and second law of thermodynamics combined with economics and environmental impact represents a very powerful tool for the systematic study and optimization of energy systems. In this study, a thermodynamic analysis of eleven selected gas turbine power plants in Nigeria was carried out using the first and second laws of thermodynamics, economic and environmental impact concepts. Exergetic, exergo-economic and exergo-environmental analyses were conducted using operating data obtained from the power plants to determine the exergy destruction and exergy efficiency of each major component of the gas turbine in each power plant. The exergy analysis confirmed that the combustion chamber is the most exergy destructive component compared to other cycle components as expected. The percentage exergy destruction in combustion chamber varied between 86.05 and 94.6%. Increasing the gas turbine inlet temperature (GTIT), the exergy destruction of this component can be reduced. Exergo-economic analysis showed that the cost of exergy destruction is high in the combustion chamber and by increasing the GTIT effectively decreases this cost. The exergy costing analysis revealed that the unit cost of electricity produced in the plants ranged from cents 1.88/kWh (₦2.99/kWh) to cents 5.65/kWh (₦8.98/kWh). Exergo-environmental analysis showed that the CO2 emissions varied between 100.18 to 408.78 kgCO2/MWh while cost rate of environmental impact varied from 40.18 $/h (N6, 388.62/h) to 276.97$/h (N44, 038.23/h). The results further showed that CO2 emissions and cost of environmental impact decrease with increasing GTIT

Suitability and optimisation of analytical indoor shelter model used for infiltration of carbon dioxide for typical dwellings

Carbon Capture Utilisation and Storage (CCUS) schemes involve transporting large quantities of carbon dioxide (CO2). A release of CO2 from CCUS transportation infrastructure could cause severe consequences for the surrounding population if the risk is not appropriately managed. Following a release of CO2, people in the surrounding environment could move away and seek shelter. The CO2 plume could drift past buildings causing the concentration of CO2 inside these buildings to build up. How much CO2 accumulates inside the buildings is key to the safety of their occupants. Previously an analytical infiltration model, based on wind and buoyancy driven ventilation, and a CFD infiltration model were created which can be used to predict the effect of CO2 exposure on building occupants following a release from an onshore CO2 pipeline [1]. These models can be used to determine the consequences of failure the dispersion behaviour of CO2 and the infiltration rate of a plume of CO2 into buildings and can form part of a Quantitative Risk Assessment (QRA) process for a CO2 pipeline. The models were validated against an experimental test of CO2 infiltration into a small enclosure. Comparisons were made between the analytical model, CFD model and experimental data for the build-up of CO2 in the enclosure and the changes in internal temperature. This paper investigates the suitability of the analytical model for buildings geometries more closely resembling domestic abodes and against a wider range of conditions by comparing its results to those of the CFD model for a set of representative case studies. It also tunes the parameters used in the model. Thirty test cases were created which explore the key parameters affecting the CO2 ventilation rate: wind speed, the area and height of the openings, internal temperature and building height, width and length. The analytical model’s predictions of the accumulation of CO2 inside a building are shown to be extremely close to the CFD results for all cases except one, where it makes an over prediction of the level of CO2. Furthermore, it is recommended that the analytical infiltration model is used with the tuned set of coefficients identified in this paper

Analytical and computational indoor shelter models for infiltration of carbon dioxide into buildings : comparison with experimental data

This paper describes two indoor shelter models – an analytical model and a Computational Fluid Dynamics (CFD) model - that can be used to predict the level of infiltration of carbon dioxide (CO2) into a building following a release from an onshore CO2 pipeline. The motivation behind the development of these models was to demonstrate that the effects of shelter should be considered as part of a Quantitative Risk Assessment (QRA) for CO2 pipeline infrastructure and to provide a methodology for considering the impact of a CO2 release on building occupants.A key component in the consequence modelling of a release from a CO2 pipeline is an infiltration model for CO2 into buildings which can describe the impact on people inside buildings during a release event. This paper describes the development of an analytical shelter model and a CFD model which are capable of predicting the change in internal concentration, temperature and toxic load within a single roomed building that is totally engulfed by a transient cloud of gaseous CO2. Application of the models is demonstrated by comparison with experimental measurements of CO2 accumulation in a building placed in the path of a drifting cloud of CO2. The analytical and CFD models are shown to make good predictions of the average change in internal concentration. Furthermore, it is demonstrated that the effects of shelter should be taken into account when conducting QRA assessments on CO2 pipelines. Document type: Articl

Analytical and computational indoor shelter models for infiltration of carbon dioxide into buildings : comparison with experimental data

This paper describes two indoor shelter models – an analytical model and a Computational Fluid Dynamics (CFD) model - that can be used to predict the level of infiltration of carbon dioxide (CO2) into a building following a release from an onshore CO2 pipeline. The motivation behind the development of these models was to demonstrate that the effects of shelter should be considered as part of a Quantitative Risk Assessment (QRA) for CO2 pipeline infrastructure and to provide a methodology for considering the impact of a CO2 release on building occupants.A key component in the consequence modelling of a release from a CO2 pipeline is an infiltration model for CO2 into buildings which can describe the impact on people inside buildings during a release event. This paper describes the development of an analytical shelter model and a CFD model which are capable of predicting the change in internal concentration, temperature and toxic load within a single roomed building that is totally engulfed by a transient cloud of gaseous CO2. Application of the models is demonstrated by comparison with experimental measurements of CO2 accumulation in a building placed in the path of a drifting cloud of CO2. The analytical and CFD models are shown to make good predictions of the average change in internal concentration. Furthermore, it is demonstrated that the effects of shelter should be taken into account when conducting QRA assessments on CO2 pipelines