Continuous Segregation and Removal of Biochar from Bubbling Fluidized Bed

Abstract Biochar is a valuable co-product with increasing agronomic and environmental values produced during pyrolysis, which is a thermochemical conversion process of biomass in the absence of oxygen. Accumulation of biochar in the bed may result in poor fluidization performance and product quality. The efficient removal of the separated biochar from the fluidized bed is therefore crucial for economical reasons. This thesis is structured in three sections. Section 1, provides an introduction and literature review on biomass pyrolysis covering the main types of processes and reactors focusing on fluidized bed technologies. It section addresses the mechanisms associated with mixing and separation processes in fluidized beds are briefly discussed. The significance of biochar recovery is also emphasized and the various current recovery methods are reviewed and discussed. Section 2 describes the methodology, the operating conditions and the variables investigated and measured in this work to generate the experimental data and ensure process reproducibility and accuracy experimental findings. Following this section, the section 3, addresses the experimental results and analysis leading to the conclusions and recommendations for future research directions. The primary objective of this research is to describe, through experimental investigations, the effects of geometrical and operating parameters on the separation efficiency and the yield of the recovered biochar in a cold simulator laboratory scale bubbling fluidized bed. A section of the bed simulates the pyrolysis reactor bed, is fluidized at high gas velocity to provide intense mixing, and a second section operates at a lower gas velocity to promote particle separation. Biochar is continuously fed to the well mixed zone to simulate the production in the reactor bed. An automated pulsating feeding inlet regulated by sleeve valves allowed continuous feeding of biochar while overflow ports in the separation section allowed for the continuous discharge of the biochar. The lab scale bubbling fluidized bed unit, made it feasible for continuous segregation and removal of biochar at an optimized separation efficiency range of 96.40 % to 98 % while operating at vigorous bubbling conditions, optimizing the separation efficiency of the biochar solids was necessary at a desirable superficial gas velocity along with the best fit submergence of the vertical baffle plate height (Ph) above the bed in preventing back mixing and bubbles from the segregation zone preventing biochar accumulation into the well mixed zone which might if not addressed result into defluidization quality in pyrolysis units. These research experimental analyses produced better results with improved separation efficiency of 92 % unlike 80 % separation efficiency achieved in previous conducted experiment. In addition, the elutriation encountered in earlier experiments accounted for \u3e 20 % fraction of the biochar fed, while the presently conducted and investigated findings successfully documented elutriation of \u3c 3 % fraction of the biochar fed into the lab scale bubbling fluidized bed unit. Following modifications of the bubbling fluidized bed pyrolyzer, the unit proved efficient in handling range of feed rates and also capable of processing different particle sizes attaining very high separation efficiency and stability (yield) states. Further optimization and adaptation for large industrial applications can be achieved through further research investigations and recommendations as suggested below. Keywords: Fluidization, Biochar, Pyrolysis, Bubbling Fluidized Bed, Biomass, Segregation, Yield, Layer Inversion, Binary mixture, Elutriation, Gas velocity, Separation Efficienc

The Use of Dietary Supplements Among African and Caribbean Women Living in the UK: A Cross-Sectional Study

Previous studies have shown that the use of dietary supplements is associated with the prevention of birth defects, negative pregnancy outcomes and cardiovascular diseases. However, there might be some ethnic disparities in supplement usage suggesting that women who could benefit from it are not frequent users. This study aimed to characterise the use of dietary supplement among Black African and Black Caribbean women living in the United Kingdom (UK). Furthermore, it evaluated possible associations between the use of dietary supplements and health and diet awareness. A total of 262 women self-ascribed as Black African and Black Caribbean living in the UK completed a comprehensive questionnaire on socio-demographic factors, diet, use of supplements and cultural factors. The main outcome variable was the regular use of any type of dietary supplement. Use of vitamin D and/or calcium was also explored. A stepwise logistic regression analysis was applied to identify predictors of regular use of dietary supplements. A total of 33.2% of women reported regular use of any dietary supplements and 16.8% reported use of vitamin D and/or calcium. There were no significant ethnic differences in the use of dietary supplements. Reporting use of the back of food packaging label (odds ratio (OR) 2.21; 95% CI 1.07–4.55); a self-rated healthy diet (OR 2.86; 95% CI 1.19–6.91) and having cardiovascular disease (CVD), hypertension and/or high cholesterol (OR 3.81; 95% CI 1.53–9.49) increased the likelihood of using any dietary supplement. However, having poorer awareness decreased the likelihood (OR 0.94; 95% CI 0.88–0.99) of using any dietary supplement. For the use of vitamin D and/or calcium supplements, the main predictor was having CVD, hypertension and/or high cholesterol (OR 4.43; 95% CI 1.90–10.35). The prevalence of dietary supplement use was low among African and Caribbean women. Thus, awareness of potential benefits of some dietary supplements (e.g., vitamin D) among the Black population should be promoted

Returns on Investment of Deposit Money Banks (DMBs) in Nigeria

This paper provides an in-depth study on the history and evolution of Commercial Bank characteristic factors and other Macroeconomic variables on the financial industry performance indices in Nigeria from 1977 to 2010. The work employed a 3-stage procedure in the assessment of Commercial Bank characteristic factors and other Macroeconomic variables on Total Credit, Investment, and Commercial Bank Lending and Deposit Rate. The essence is to assess the impact of environmental factors on efficiency of commercial banks in Nigeria within the period of study. While investigating relationships between bank efficiency and bank specific factors such as lending rate, deposit rate, Liquidity, Cash Reserve, and Inflation and also the impact of bank efficiency on those bank level factors as well as financial deepening. The study using econometrics approach revealed that apart from credit risk, Lending, Deposit rates, and Investments are associated with large bank size as evident in the network of branches. The results indicated that Returns and Profitability of Commercial Banks are significantly affected by Macroeconomic variables and other characteristic factors. As such macroeconomic policies are likely to promote low inflation while stable output growth may boost credit expansion to the benefit of the Nigerian economy

Physical and Release Properties of Metronidazole Suppositories

Purpose: A study was made of the effects of some bases and adjuvants on the physical and release properties of metronidazole suppositories with a view to providing more information for the optimization of the rectal formulation of metronidazole. Method: Suppositories (1g) containing 200mg of metronidazole each were prepared in witepsol (H15 and E75) and polyethylene glycol (PEG 2850 and 4650) bases, using different concentrations of Tween 80, sodium salicylate and methylcellulose as adjuvants. The setting time, solidification point and melting range of the suppositories were determined, along with their crushing strength, disintegration time and the time for 80% of metronidazole to be released from the suppositories (t80). Results: The ranking of setting time for the suppositories was witepsol H15 > PEG 2850 > witepsol E75 > PEG 4650, while the ranking of solidification point, melting range, crushing strength, disintegration time and the time for 80% of metronidazole to be released from the suppositories (t80) was the reverse of that for setting time. Optimal concentrations of Tween 80 and sodium salicylate were observed for the suppository formulations. Using Kitazawa plots, all formulations showed two dissolution rate constants, k1 and k2 intersecting at time t1, with formulations containing 5 to 20 % w/w of methylcellulose exhibiting a third dissolution rate constant, k3 intersecting with k2 at time t2. Conclusion: The physical and release properties of metronidazole suppositories are influenced considerably by the bases and adjuvants employed. Tween 80 and sodium salicylate can probably be used to formulate only immediate-release suppositories while methylcellulose can be useful for sustained-release metronidazole suppositories. Some insight into these inferences can be obtained from parameters derived from Kitazawa plots. Keywords: metronidazole, suppository bases, adjuvants, physical and release properties, Kitazawa plots. Tropical Journal of Pharmaceutical Research Vol. 7 (1) 2008: pp.887-89

Predicting Bank Failure in Nigeria Using Survival Analysis Approach

The collapse and failure of a bank could have devastating consequences to the entire banking system and widespread repercussion effect on other banks and the economy as a whole. The main objective of this paper is to determine how bank failure in Nigeria can be predicted far ahead of its occurrence using a survival analysis approach. The paper identifies the financial distress symptoms that can lead to a bank failure by employing the Cox Proportional Hazards Model using financial covariates from financial statements of banks. Panel data covering a period from 2003 to 2011 were analysed. The study shows that survival of banks in Nigeria is mostly influenced by 12 predictor variables that bank regulators could watch out for, to forestall bank distress. The study shows that banks that are high on non-performing loan to total loan plus lease and with high operating expense to average total assets have very high tendency of failure. Another interesting finding is that average survival time for banks in Nigeria varies significantly according to their specialty. The study therefore recommends that the reform activities of the government should be well thought out and strategies for implementation should be put in place to enhance positive effect on the banking sector in Nigeria

Empirical Modelling of the Impact of Financial Innovation on the Demand for Money in Nigeria

Financial innovation refers both to technological advances which facilitate access to information, trading and means of payment. The demand for money is very crucial in the conduct and determination of the effectiveness of monetary policy. This study attempts to analyse whether financial innovations that occurred in Nigeria after the Structural Adjustment Programme of 1986 has affected the demand for money in Nigeria using the Engle and Granger Two-Step Cointegration technique. Though the study revealed that demand for money conforms to the theory that income is positively related to the demand for cash balances and interest rate has an inverse relationship with the demand for real cash balances, it was also di scovered that the financial innovations introduced into the financial system have not significantly affected the demand for money in Nigeria. Based on the results obtained, a policy of attracting more patticipants (non-government) and private sector funds to the money market is necessary as this will deepen the market and make the market more dynamic and amenable to monetary policy. Therefore, the study concludes that financial innovation has had no significant impact on the demand for money in Nigeria and the SAP era financial liberalization policies have had no indirect impact on the demand for money as well

Effects of Solid Wastes on the Quality of Selected Well Water in Odo-Oro Area of Ikere, Ekiti in Nigeria

This paper presents an assessment of the impact of uncontrolled and unscientific disposal of Solid waste on ground water in Ikere Ekiti town, Nigeria. In this study, well water quality around solid waste dumpsite sites was investigated. Ground water quality analysis was carried out on water samples collected from four wells labelled 1 to 4 close to solid waste disposal sites. Physico-chemical parameters of the water samples (such as temperature, pH, conductivity, dissolved oxygen, BOD, COD, turbidity, total dissolved solids, total suspended solids, total hardness, phosphates, sulphates, chlorides and nitrates) were measured. Results of analysis across the four samples gave a temperature range of 280C - 32.00C, pH 7.26 - 7.75, conductivity 393.0 - 416.0 µm/cm, BOD 4.0 - 4.5 mg/l, DO 7.5 - 9.9 mg/l, COD 4.0 - 70.0 mg/l, phosphates, sulphates, chlorides and nitrates 0.17 – 0.30 mg/l, 10.1 – 25.0 mg/l, 3.7 – 11.5 mg/l, and 0.113 - 0.22 mg/l respectively, total hardness 32.2 and 38.1 mg/l. evidences from the above measurements showed a substantial level of contamination across all samples of water. Based on these outcomes it was recommended that wells should be sited at least 30m from solid wastes dump site, Appropriate place should be located at the outskirt of the town for refuse / disposal, the wells should be treated at least three times in a year, the regulatory agency should employ a geologist on its staff list, preferably one trained in the area of hydrogeology, to assist in solid wastes site selection within the states, the use of groundwater monitoring wells should be considered in those areas where some doubts exist as to future effects of a particular solid wastes operation, the regulatory agency should not discourage novel methods of collecting and treating refuse leachates for certain installations where proper monitoring can be exercised. Keywords: Solid Waste, Well Water, Ground water, Dump Site, Physico-chemical, DOI: 10.7176/JEES/10-7-05 Publication date:July 31st 202

Temperature Performance Evaluation of Parabolic Dishes Covered with Different Materials in Iwo, Nigeria

Solar radiation reaching the earth is considered to be affected by some parameters like diffusion. This radiation is reflected or scattered by air molecules, cloud and aerosols (dust). Parabolic dishes made of different materials (glass, foil and painted surface) were used to concentrate energy on a copper calorimeter filled with water. A thermometer was inserted in each of the copper calorimeter placed at the focus of the dishes. The experiment was performed from March to April (a period of five weeks), from 9:00am to 5:00pm daily with readings obtained at intervals of 30 minutes every day for one week and was later changed to hourly readings for the remaining four weeks. The initial and final temperatures of the water were determined. The parabolic dish with glass material gave the highest temperature of 56.9oC followed by foil with an average temperature of 48.7oC and painted silver colour with an average temperature of 45.1oC for the daily variation. For the other weeks, the average temperature of the dish with glass was 57.6oC  for foil, 46.9oC and painted silver colour, 40.8oC. The parabolic dish with glass is able to generate a higher temperature compared with foil and painted silver colour. Keywords: Glass, Foil, Silver Colour and Parabolic Dish

Re-activation of a Small Hydropower(SHP)Plant: Oyan SHP Station,Nigeria

Electricity production in small hydropower (SHP) plants can be increased without the need for the construction of new SHP scheme, but by upgrading and optimizing different aspects of existing plant's operations. An assessment of the electromechanical equipment that suites the existing heads, discharge or flow rates and other electromechanical parameters at the Oyan SHP plant, using Retscreen Clean Energy Project Analysis Software and hydraulic turbine specific speed equation ( ) to evaluate plant performances was carried out in this work. Two cases involving upgrading of the electromechanical equipment to yield 10 and 12 MW of installed capacities respectively were considered, while at the same time maintaining the existing structures such as the weir, powerhouse and penstocks. The two cases were analysed and compared with a reference case (the existing installed capacity generation of 9 MW). Findings in terms of the financial and economic analysis for optimum installation and operation, favoured the 10 MW installation. Energy gain by installing the 10 MW is 33.37% relative to the reference case while the 12 MW is 5% compared with the reference. The simple payback for the 10 and 12 MW capacities is 11 and 13 months respectively. Hence, upgrade and optimization to 10 MW is found to be a more profitable option than the 12 MW capacity