Mixing characteristics of bubble columns with internals for Biomass to liquid synthesis [abstract]

Only abstract of poster available.Track II: Transportation and BiofuelsThe use of renewable energy sources is becoming increasingly necessary, if we are to achieve the changes required to address the impacts of global warming. Biomass is the most common form of renewable energy, widely used in the third world but until recently, less so in the Western world. Latterly much attention has been focused on the conversion of biomass to liquid fuels; a process which would greatly increases the potential usefulness of biomass as a renewable resource. Conversion of biomass to liquid is carried out by first gasification of biomass to yield synthetic gas. The synthetic gas can then be converted to liquid fuels using Fischer Tropsch process or transformed to methanol for subsequent use as a chemical, solvent or fuel. For large-scale FT / methanol synthesis the slurry bubble column reactor is the best choice. These reactors offer high conversion and high volumetric productivity when operated in the heterogeneous or churn turbulent regime. Notwithstanding the presence of large diameter bubbles and their short residence time in the liquid, gas-liquid mass transfer is quite fast in this regime due to the effective interaction between bubbles of various sizes. However, despite the simple construction and operation of bubble columns, their scale-up is very difficult due to complex interrelations among the many parameters that determine the behavior of bubble columns. In addition the complexity increases with the presence of cooling internals that affect the hydrodynamics and mixing behavior in bubble columns. Gas phase backmixing is one of the important hydrodynamic parameters to be considered in the scale-up of bubble columns as it can adversely affect the reaction rates and product selectivity. The present investigation focuses on studying the effect of the cooling internals on gas phase mixing behavior. The percentage of internals used in this study is the same percentage used industrially for methanol synthesis (5 % internals) and FT synthesis (25% internals)

Advancement of TRISO Nuclear Fuel Coaters for High Temperature Pebble Bed Nuclear Reactors: Environmentally Benign and Risk Free Proliferation 4th Generation Nuclear Energy [abstract]

Only abstract of poster available.Track I: Power GenerationThe success on nuclear energy produced by advanced high temperature gas reactors (AGRs) is dependent on tri-isotropic (TRISO) fuel particle coating. Today modern AGRs require essentially zero defective/failed coated particles. Unfortunately, the scale-up and design of the current coating processes using gas-solid spouted beds have been based on empirical approaches and are operated as “black boxes” due to lack of fundamental understanding of the hydrodynamics of spouted bed coaters. Further complicating future fuel-coating technology and nuclear energy production is the fact that fuel kernels of different sizes and densities are required to be manufactured. Therefore, in order to prevent the large risk associated with producing particles that do not meet the specifications, a fundamental understanding of the phenomena occurring in the spouted bed TRISO coater is needed. Accordingly, the overall research objectives of this project are 1) to advance the fundamental understanding of the hydrodynamics TRISO fuel coaters by systematically investigating the effect of design and operating variables, 2) to evaluate the reported dimensionless groups as scaling factors, 3) to establish a reliable scale-up methodology for TRISO fuel particle spouted bed coaters based on hydrodynamics similarity via advanced measurement and computational techniques, and 4) to develop an on-line, non-invasive measurement technique based on gamma ray densitometry (i.e., Nuclear Gauge Densitometry) that can be installed for industrial coater process monitoring to ensure proper performance and operation and to facilitate the developed scale-up methodology. To achieve these objectives the following research tools will be implemented and/or developed: • Optical probes for solid and gas holdup and solids velocity distribution measurements. • Gamma ray computed tomography (CT) for measuring the solid and gas holdup cross-sectional distribution along the spouted bed height, spouted diameter, and fountain height. • Radioactive particle tracking (RPT) technique for measuring the 3D flow patterns and field, solids velocity, turbulent parameters, circulation time, and many others. • Gas dynamics measurement technique. • Pressure transducers. In this presentation, the results and findings that are so far obtained with will be discussed and the work in progress will be outlined

Fundamental Understanding of Pebble Bed Nuclear Reactors for Environmentally Benign and Risk Free Proliferation 4th Generation Nuclear Energy and Hydrogen Production [abstract]

Abstract only availableTrack I: Power GenerationPebble bed nuclear reactor is among the 6 suggested 4th generation nuclear reactors. It is also one of the advanced high temperature gas nuclear reactors (AGRs). In such reactor the pebbles that contain the nuclear fuel particles (TRISO) (~900-950 micron) move downward while high temperature helium moves upward. These pebbles are circulated until they are spent. The pebble bed nuclear reactors are characterized as environmentally benign, risk free proliferation with high thermal efficiency (about 55% while the current nuclear reactor technology provides ~ 35%). The fundamental understanding of these reactors is lacking. Therefore, this work as a part of the research program on high temperature reactors through the consortium consists of University of Missouri - Columbia, Missouri S&T, North Carolina State University focuses on the detailed hydrodynamics of the pebbles movement, gas dynamics and heat transfer using both advanced measurement and computation techniques. The progress made on this project at Missouri S&T will be presented and the future work will be outlined

Evaluation of ADA, IL-6 and TNF-alpha level in type 2 diabetes mellitus: with -and without hypoglycemic drugs.

Diabetes mellitus(DM) is a major worldwide  health problem leading to markedly increase mortality and serious morbidity. Immunological disturbances involving the cell mediated immune system and improper T-lymphocyte function also contribute to the path physiology of type 2 DM.It has been reported that ADA,IL-6,and TNF-α levels  were a good marker for immunological disturbance in type 2 DM  patients.This study aims to assess and compare the level of serum ADA, IL-6 ,and TNF-α in patient of type 2 DM with and without oral hypoglycamic drugs.The study population consist of 150 subjects divided in to 3 groups:group I (50normal health controls),group II (45 type 2 DM patients with no on hypoglycemic drugs),and group Ш (55 type 2 DM patients on hypoglycemic drugs).There were a significant(p<0.001) tremendous increase in ADA,IL-6,and TNF-α levels (47.32 U/L ,29.04 pg/ml ,and 98.23 pg/ml, respectively ) in group II  than group I and group Ш. also, ADA,IL-6,and TNF-α levels were significantly(p<0.001) higher in group Ш than group I.As conclusion ,the increase in ADA,IL-6,and TNF-α levels  is a good glycemic  markers associated with type 2 DM .The intake of hypoglycaemic drugs  decrease the levels of these markers. Key words: ADA activity , IL-6 , TNF-α , type 2 diabetes mellitus

Multi-layer perceptron neural network mobile robot navigator in unknown environment

Recently, navigation in an unknown environment without hitting obstacles was considered a big challenge faced by researchers. The difficulty in finding a good mathematical model for the different systems is deciding to use artificial intelligent controllers to control the mobile robot movement. In this paper, designing two multi-layer-perceptron neural networks (MLP-NN) was done to control the movement of mobile robots in an unknown environment. The first MLP-NN is to control the linear velocity on the x-axis and angular velocity of the robot’s movement while the other MLP-NN is designed to avoid the static and dynamic obstacles faced by the robot while navigating in an unknown environment. The results show each controller's advantages in performing navigation tasks and avoiding obstacles in different environments

GAS PHASE MIXING IN BUBBLE COLUMNS WITH INTERNALS

The use of renewable energy sources is becoming increasingly necessary, if we are to achieve the changes required to address the impacts of global warming. Biomass is the most common form of renewable energy, widely used in the third world but until recently, less so in the Western world. Latterly much attention has been focused on the conversion of biomass to liquid fuels; a process which would greatly increases the potential usefulness of biomass as a renewable resource. Conversion of biomass to liquid is carried out by first gasification of biomass to yield synthetic gas. The synthetic gas can then be converted to liquid fuels using Fischer Tropsch process or transformed to methanol for subsequent use as a chemical, solvent or fuel. For large-scale FT / methanol synthesis the slurry bubble column reactor is the best choice. These reactors offer high conversion and high volumetric productivity when operated in the heterogeneous or churn turbulent regime. Notwithstanding the presence of large diameter bubbles and their short residence time in the liquid, gas–liquid mass transfer is quite fast in this regime due to the effective interaction between bubbles of various sizes. However, despite the simple construction and operation of bubble columns, their scale-up is very difficult due to complex interrelations among the many parameters that determine the behavior of bubble columns. In addition the complexity increases with the presence of cooling internals that affect the hydrodynamics and mixing behavior in bubble columns. Gas phase backmixing is one of the important hydrodynamic parameters to be considered in the scale-up of bubble columns as it can adversely affect the reaction rates and product selectivity. The present investigation focuses on studying the effect of the cooling internals on gas phase mixing behavior. The percentage of internals used in this study is the same percentage used industrially for methanol synthesis (5 % internals) and FT synthesis (25% internals)

Flow regime identification in fluidized beds by analysing pressure fluctuations signal based on kolomogrov entropy approch

The investigation of flow regime in gas-solid fluidized bed reactors is very important for their design and scale-up as well as effective operation. In addition, the degrees of mixing, mass and heat transfer in these reactors depending strongly on the common flow regime. In the present work, pressure transducer technique has been used to generate pressure fluctuations signal in gas-solid fluidized bed of 13.97 cm ID. Different static bed heights, different particles size and particles density of both Geldart A and B as well as a range of superficial gas velocity (15-100) cm/s have been used to study the flow regime identification. The Kolmogorov entropy (KE) approach analysis has been applied to pressure fluctuations signal recorded in fluidized bed. The (KE) is considered as a universal tool for the accurate identification of the boundaries of the main hydrodynamic regimes in multiphase reactors. It has been shown that this approach leads to successful identification of the main flow regimes in fluidized bed reactors with different operating conditions. REFERENCES 1- Nedeltchev, S., Aradhya, S., Zaid, F., & Al-Dahhan, M. (2012). Flow regime identification in three multiphase reactors based on Kolmogorov entropies derived from gauge pressure fluctuations. Journal of Chemical Engineering of Japan, 45(9), 757-764. 2- Nedeltchev, S. (2015). New methods for flow regime identification in bubble columns and fluidized beds. Chemical Engineering Science, 137, 436-446. 3- Nedeltchev, S., Ahmed, F., & Al-Dahhan, M. (2012). A new method for flow regime identification in a fluidized bed based on gamma-ray densitometry and information entropy. Journal of chemical engineering of Japan, 45(3), 197-205. 4- Johnsson, F., Zijerveld, R. C., Schouten, J. C., Van den Bleek, C. M., & Leckner, B. (2000). Characterization of fluidization regimes by time-series analysis of pressure fluctuations. International journal of multiphase flow, 26(4), 663-715. 5- Bi, H. T. (2007). A critical review of the complex pressure fluctuation phenomenon in gas–solids fluidized beds. Chemical Engineering Science,62(13), 3473-3493. 6- van Ommen, J. R., Sasic, S., Van der Schaaf, J., Gheorghiu, S., Johnsson, F., & Coppens, M. O. (2011). Time-series analysis of pressure fluctuations in gas–solid fluidized beds–A review. International Journal of Multiphase Flow,37(5), 403-428. 7- Nedeltchev, S., Jordan, U., Lorenz, O., & Schumpe, A. (2007). Identification of various transition velocities in a bubble column based on Kolmogorov entropy.Chemical engineering & technology, 30(4), 534-539. 8- Nedeltchev, S., Shaikh, A., & Al‐Dahhan, M. (2011). Flow regime identification in a bubble column via nuclear gauge densitometry and chaos analysis.Chemical engineering & technology, 34(2), 225-233. Muzen, A., & Cassanello, M. C. (2007). Flow regime transition in a trickle bed with structured packing examined with conductimetric probes. Chemical engineering science, 62(5), 149