Performance and Thermoeconomic Analysis of a Biogas Engine Powered Ventilation System for Livestock Building

In this study, a biogas engine powered ventilation fan of a small swine farm was proposed. The research objective was to evaluate performance of, and apply a thermoeconomic analysis to an active ventilation system powered by a small biogas engine. Comparison was made against a gasoline engine and an electric motor. The engine used was a single-cylinder, four-stroke, spark ignited engine with capacity of 118 cm3. The biogas engine was found to be practically able to drive the ventilation fan with acceptable operation over a range of speeds and loads. At null price for biogas, the biogas engine proved to offer the lowest cost per product exergy unit at $0.054/MJ, which was considerably lower than the gasoline engine and electric motor

Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content

Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1 from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higher E values were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal

Predicting Ash Deposit Tendency in Thermal Utilization of Biomass

In thermochemical utilization of biomass, ash produced during the process is a major problem that can result in decreased performance and increased in difficulty during operation. Preliminary assessment of potential ash related troubles prior to the use of a specific biomass is valuable, even if it is only a general guideline. In this work, tendency of ash slagging, fouling and agglomeration in thermal processing of biomass was evaluated. Reference peered reviewed data including mineral content and fusion temperature of selected biomass ash were used to calculate multiple indicators (base to acid ratio, slagging index, fouling index, agglomeration index, slag viscosity index, and ternary diagram of main biomass ash composition) adopted from coal research. Major ash forming elements (Fe, Ca, Mg, K, Na, Al, Si) were found to be of relevance to ash melting and deposit behavior. For conventional biomass available locally, woody biomass (wood and wood sawdust) may be combusted without slagging or fouling problem, while non-woody biomasses (bark, husk, straw) are highly probable to experience some of these problems. The ash fusibility predictive models for woody and non-woody biomass were found to be effective. Mitigation can then be designed possibly via fuel blending to avoid or minimize the impact of biomass ash related trouble

Partial oxidation reforming of simulated biogas in gliding arc discharge system

Plasma assisted, partial oxidation reforming of biogas is considered to be a promising technology to produce synthesis gas. In this work, a 0.1 kW gliding arc plasma reformer was employed to investigate the effects of biogas composition and oxygen availability on CH4 and CO2 conversions, as well as the product distribution. Air was used in the partial oxidation of biogas. The results showed that at low CH4/O2 ratio or high oxygen availability, increasing CH4 content appeared to show higher H2 yield and CH4 conversion. Increasing CH4/O2 ratio adversely affected H2 and CO yields, and CH4 conversion. Optimum condition was found at CH4/CO2 of 90:10 and CH4/O2 of 1.2 for the maximum CH4 conversion and H2 yield of 45.7 and 25.3%, respectively

Factors Affecting Efficient Supply Chain Operational Performance of High and Low Technology Companies in Thailand

This paper was about comparison between two groups of companies with different characteristics of technology intensity on their supply chain operational performance and potential factors that constitute efficient supply chain operational performance. Data collection was conducted for the manufacturing sector in Thailand where 407 participants evaluated themselves using an SCM Logistics Scorecard (LSC). The LSC focused on four decisive areas, namely, (i) corporate and inter-organization alignment, (ii) planning and execution capability (iii) logistics performance and (iv) IT implementation and management. The LSC score was compared between high and low technology groups to identify their strengths and weaknesses. Attempt was made to identify the potential factors leading to improvement of supply chain management for both groups of companies.Keywords: Technology intensity; High technology industries; SCM, Supply chain operational performance; Factor analysi

Experimental Investigation of Biogas Reforming in Gliding Arc Plasma Reactors

Biogas is an important renewable energy source. Its utilization is restricted to vicinity of farm areas, unless pipeline networks or compression facilities are established. Alternatively, biogas may be upgraded into synthetic gas via reforming reaction. In this work, plasma assisted reforming of biogas was investigated. A laboratory gliding arc plasma setup was developed. Effects of CH4/CO2 ratio (1, 2.33, 9), feed flow rate (16.67–83.33 cm3/s), power input (100–600 W), number of reactor, and air addition (0–60% v/v) on process performances in terms of yield, selectivity, conversion, and energy consumption were investigated. High power inputs and long reaction time from low flow rates, or use of two cascade reactors were found to promote dry reforming of biogas. High H2 and CO yields can be obtained at low energy consumption. Presence of air enabled partial oxidation reforming that produced higher CH4 conversion, compared to purely dry CO2 reforming process

Design and Performance Analysis of a Biodiesel Engine Driven Refrigeration System for Vaccine Storage

A compact, stand-alone, refrigeration module powered by a small biodiesel engine for vaccine storage in rural use was proposed. The engine was of single cylinder, four-stroke, directinjection with displacement of 0.296 cm3 and compression ratio of 20:1. The refrigeration system was modified from an automotive vapor compression system. The system performance was analytically investigated. From the simulation, it was found to have acceptable operation over a range of speeds and loads. Performance of the system in terms of fuel consumption and torque tended to decrease with an increase in engine speed. The modular system was able to operate at cooling loads above 4.6 kW, with proper speed ratio between the engine and the compressor. Overall, primary energy ratio of the refrigeration was found to be maximum at 0.54

Reaction Kinetics of Transesterification Between Palm Oil and Methanol under Subcritical Conditions

The objective of this work was to evaluate transesterification kinetics for biodiesel production from palm oil under subcritical conditions. Experimental investigation was carried out with palm oil and methanol at molar ratio of 46:1, temperatures between 150-200 °C and pressure around 140-190 atm in a 400 ml batch  reactor.  The biodiesel products were analyzed by gas chromatography – mass spectrometry. Area percentage method was used to estimate the methyl esters in the product. Zero- and first-order kinetic models were developed. Apparent activation energy was estimated to be in the range of 91-105 kJ/mol. The reaction rate equation was best approximated by the first order kinetic model with pre-exponential factor of 1.57 x 109.Key words: Biodiesel; Critical fluids; Kinetic equations; Methyl esters; Palm oil; Renewable energ

Forecasting arabica coffee yields by auto-regressive integrated moving average and machine learning approaches

Coffee is a major industrial crop that creates high economic value in Thailand and other countries worldwide. A lack of certainty in forecasting coffee production could lead to serious operation problems for business. Applying machine learning (ML) to coffee production is crucial since it can help in productivity prediction and increase prediction accuracy rate in response to customer demands. An ML technique of artificial neural network (ANN) model, and a statistical technique of autoregressive integrated moving average (ARIMA) model were adopted in this study to forecast arabica coffee yields. Six variable datasets were collected from 2004 to 2018, including cultivated areas, productivity zone, rainfalls, relative humidity and minimum and maximum temperatures, totaling 180 time-series data points. Their prediction performances were evaluated in terms of correlation coefficient (R2), and root means square error (RMSE). From this work, the ARIMA model was optimized using the fitting model of (p, d, q) amounted to 64 conditions through the Akaike information criteria arriving at (2, 1, 2). The ARIMA results showed that its R2 and RMSE were 0.7041 and 0.1348, respectively. Moreover, the R2 and RMSE of the ANN model were 0.9299 and 0.0642 by the Levenberg-Marquardt algorithm with TrainLM and LearnGDM training functions, two hidden layers and six processing elements. Both models were acceptable in forecasting the annual arabica coffee production, but the ANN model appeared to perform better

Bio-Oils From Vacuum Ablative Pyrolysis of Torrefied Tobacco Residues

Fast pyrolysis, in combination with torrefaction pretreatment, was used to convert tobacco residues to value-added bio-fuels and chemicals. Tobacco plant residues were torrefied at 220, 260, and 300 °C, before being pyrolyzed at 450, 500, 550, and 600 °C in a rotating blade ablative reactor under vacuum conditions to test the effects on product yields. With torrefaction, tobacco residues thermally decomposed 20-25% w/w at low temperatures. Torrefaction and pyrolysis temperatures were found to markedly affect pyrolytic product yields of bio-chars and bio-oils, while having no effect on gas-phase products. Bio-oil yields exhibited a direct relation with pyrolysis temperature and an inverse relation with torrefaction temperature. Bio-oils produced were separated into light and heavy oils and analyzed by GC-MS, and1H and13C NMR. Nicotine was found to be the main compound in the light and heavy oils along with several phenols and cresols in the heavy oil