Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 119-125). Also available via the Internet.

Hog fuel is increasingly becoming an alternative to alleviate the energy problems associated with the use of fossil fuels. To make adequate use of hog fuel, its moisture content should be reduced prior to combustion either in an external dryer or in the initial stages of a hog fuel boiler. Therefore, this research project was undertaken to establish the factors which govern the drying rate of wet hog fuel particles. The convective drying of wood-waste on the slow moving bed of hog fuel boilers was simulated in a packed bed. The information which was obtained can also be applied to approximate the drying behaviour in external dryers. An apparatus was constructed to accommodate the use of hot air, flue gas, superheated steam and a mixture of them as drying media. Drying tests were carried out, over the temperature range of 125-245°C, on 1.1 to 4 kg batches of Western Hemlock hog fuel of thicknesses from 2 to 12 mm. The relative effects of velocity (V), temperature (T), nature of the drying gas, bed depth (L), and initial moisture content of the hog fuel samples (M₀) on the drying process were investigated using a mixture of several thickness fractions having an average (sauter mean) particle thickness (dp) of 6.3 mm. Drying rates were determined through measurement of the change either in humidity of the drying gas, or flow rate of the superheated steam across the bed of hog fuel. Gas humidity was measured using an optical dew point sensor and steam flow was monitored using an orifice plate connected to a massflow transmitter. Drying rates have been quantified as functions of hog fuel particle thickness, initial moisture content and bed depth. The effects of gas temperature, velocity and humidity have also been quantitatively established. The drying process was insensitive to CO₂ content of the drying gas. The existence of an inversion temperature above which drying rates increase with humidity of the drying medium was both experimentally and theoretically confirmed and the locus of inversion points was determined. Instantaneous normalized drying rates, ƒ, and characteristic moisture contents, Φ , have been determined and the existence of a unified characteristic drying rate curve was verified. Using a receding plane model, ƒ was formulated as a function of Φ, for dp = 6.3 mm and at L = 25 cm, for both superheated steam and relatively dry air. Pressure drop measurements were obtained for all the runs with the exception of the superheated steam ones. Application of an accepted pressure drop equation permitted the sphericity of the hog fuel particles to be approximated. A design equation for gas pressure drop in beds of hog fuel particles was investigated. The simultaneous heat and mass transfer processes in drying during the heat transfer controlled period was studied. Using the concept of volumetric evaporation, an empirical correlation for the overall heat transfer coefficient in a packed bed of hog fuel particles has been obtained. The effects of different parameters on both the particle residence time required for drying and the grate heat release rate in hog fuel boilers were determined. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

No description available.

A pile of mixed hardwood whole tree chips was monitored for one year to identify the effects outside storage would have on the fuel potential of the exposed pile. A 20 foot conical pile was built by gravity feed from an overhead conveyor. Moisture content, fiber loss, ash, specific gravity, higher heating value (HHV), temperature, packing density and pH were the variables examined and from these changes, Total Net Heating Value was estimated. Moisture content and packing density showed a significant increase with time. Pile temperature remained below freezing for the first ten weeks of the study then rapidly rose above the ambient air temperature to a maximum of 82 degrees C before falling to near ambient where it remained. After six months,moisture content within the pile stratified into layers reflecting steep moisture content gradients. The outermost layer became saturated, primarily due to rainfall while spontaneous drying reduced the innermost layer's moisture content. The Total Net Heating Value (TNHV) was found to decrease 1.14 percent per month or 13.7 percent a year. Increased moisture content accounts for 88.5 percent of the loss. Lower HHV accounts for 11.5 percent of the loss in TNHV. Storage suggestions and recommendations are included / M.S.

The major objectives of this study were to: 1. evaluate the financial aspects of improvement thinnings for fuelwood in Appalachian hardwood stands. 2. determine direct net energy values from energy inputs and outputs for fuelwood harvesting in Appalachian hardwoods. The landowners decision on whether or not to thin was greatly influenced by haul distance and his opportunity cost for time spent harvesting wood. Other considerations included the market price for both firewood and firewood stumpage. Two cases were analyzed using discounted cash flows, the first considered the landowner as a firewood consumer. The results of this portion indicated that at low haul distances (< 15 miles) and low opportunity costs ($0 to 5 per hour), the landowner should produce his own firewood. At longer haul distances an open market purchase should be made and at higher opportunity costs a contractor should be hired to harvest the firewood. In the second case, the landowner acted as a firewood producer. The results indicate that at low haul distances and low opportunity costs of harvesting, the landowner can attain reasonable rates of return on the investment (approximately 4% after-tax in real terms). At greater haul distances and higher opportunity costs the investment returns diminish. The second objective concerning energy resulted in favoring larger scale operations at longer haul distances and smaller operations at shorter distances. The major influences on energy values were haul distance and degree of mechanization. Overall, this analysis presents a process for evaluating firewood thinnings and offers the landowner the capability of examining a variety of sites and harvest systems. However, the results should be viewed only as an example situation. / Master of Science

Forest and fuel wood are fundamental as sources of energy in almost all developing economies. However there are a few empirical studies addressing the issue of fuelwood production and consumption for rural households. In this paper, household fuelwood use behavior is empirically assessed and policy implications are drawn. with specific reference to Nepal's tarai and mid-hills. Fuelwood production, supply and demand functions are estimated using market, forest and access, and demographic variables characteristic of each region. Both regional and district level supply and demand elasticities are also estimated with respect to opportunity cost of labor, fuelwood price, income, resource stock and access, and demographic variables. The results suggest that rural households produce and consume fuelwood according to the opportunity cost of their labor and market fuel wood prices. Market( economic) variables such as fuel wood price and opportunity costs of labor along with forest stock and its access can provide better insights for assessing household responsiveness to forestry and related development activities and for policy than mere resource stock size or its access. / Master of Science

The literature was reviewed to determine the probable characteristics of short-rotation energy plantations. The influences these plantation characteristics would have on harvesting machine and system design were evaluated. Significant plantation and system characteristics affecting the harvesting of energy biomass include species, spacing, rotation, generation, row and road layout, plantation size, soil type, terrain, and end-product form. A prototype short-rotation energy plantation harvester attachment for a medium-size farm tractor or skidder was described and is under construction. Tests were performed on two types of circular saws as severance devices. The tests concluded that circular carbide-tipped peg-tooth saws were an efficient method of cutting the stems, requiring only about 9 net horsepower and leaving very cleanly-cut stump surfaces. The prototype harvester system and three other large existing or conceptual biomass harvesters were simulated on a 100 acre short-rotation energy plantation under three spacing and three rotation assumptions. Simulation results showed that wider (4' x 4' to 8' x 8’) spacings gave slightly lower harvesting costs and better productivities than 2' x 2' spacings. Rotations or generations with more volume per stem generally resulted in lower harvesting costs. The VPI short-rotation harvesting attachment system had harvesting costs and productivities comparable to the large, single-purpose machines (SIKOB harvester, Koch-Nicholson Mobile Chipper, and the Georgia-Pacific Biomass Harvester). The most favorable harvesting costs were about $10 per dry ton of chips; the most favorable system productivities were about 7 to 10 dry tons per hour. / Master of Science

Thesis (MScFor)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Wood scarcity remains the main challenge for many rural households who still rely on natural resources for energy needs. This study aimed to investigate the relationship between fuel use and quality and quantity of fuel in two rural villages (Ongulumbashe and Onaitembu) in the Omusati Region of Namibia. It investigated the impact of fuel quality and quantity and the corresponding sales of firewood on households’ energy consumption. Data was collected between April and June 2012 from the two villages by means of questionnaire surveys, biomass assessment and laboratory assessment. Interviews were conducted with seventy-seven households, four firewood sellers, government officials, and local leaders. The study quantified the amount of fuelwood consumed and collected per household per week using user-recall and physical measurement, respectively. The most preferred fuel species or fuel materials were identified and their physical properties, calorific value, moisture content, ash content and density were measured under laboratory conditions. Differences between the two villages in terms of fuelwood collected and consumed were found. Due to wood scarcity households from Onaitembu village used other alternatives (buying fuelwood and cutting live firewood) rather than collecting dead firewood. The study found a link between fuelwood use, quality and quantity, with households changing their consumption and harvesting based on season, fuelwood demand and availability of fuelwood. The average weekly fuelwood consumption per household ranged from 66 kg to 79 kg for a firewood abundant area and from 59 kg to 67 kg for an area with a shortage of firewood. Mopane was the most preferred species due to its ability to burn efficiently and its abundance. Wood scarcity affected households economically, culturally and nutritionally. The study found that households in degraded areas spend an average of N$ 50 per week on fuelwood, and many households depended on government grants and small cash income activities. The study found that the government, through the Ministry of Agriculture, Water and Forestry, is trying to improve rural households’ energy use by constructing firewood outlets. The study concluded that there is a high level of illegal trade in firewood that will require government to increase the number of staff in the region as well as to strengthen its policy on cross-border trading. There is an imbalance in fuel species use in areas of rich biomass and over-utilization of resources in degraded areas. These require the Directorate of Forestry to educate the community about the value of other possible fuel species and the impact of harvesting live firewood on households’ livelihood and on the environment. / AFRIKAANSE OPSOMMING: Houtskaarsheid bly die grootste uitdaging vir baie landelike huishoudings, wat nog steeds staatmaak op natuurlike hulpbronne vir energie behoeftes. Hierdie studie het gepoog om die verhouding tussen brandstof gebruik en kwaliteit en kwantiteit van brandstof in twee plattelandse dorpies (Ongulumbashe en Onaitembu) in die Omusati-streek van Namibië te ondersoek. Die impak van brandstof kwaliteit en kwantiteit en verkope van brandhout op huishoudings se energie gebruik is ondersoek. Data is ingesamel in April en Junie 2012 in die twee dorpe deur middel van vraelys opnames, biomassa assessering en laboratorium ontledings. Onderhoude is gevoer met 77 huishoudings, vier brandhoutverkopers, regeringsamptenare, en plaaslike leiers. Die studie het die hoeveelheid vuurmaakhout verbruik en versamel per huishouding per week gekwantifiseer deur gebruik te maak van gebruikergeheue en fisiese meting van vuurmaakhout. Die mees gewilde brandstof spesies of brandstof materiaal is geïdentifiseer en hul fisiese eienskappe, kaloriewaarde, voginhoud, asinhoud en digtheid is onder laboratorium toestand gemeet. Verskille tussen die twee dorpe in terme van brandhout versamel en verbruik is gevind. As gevolg van houtskaarsheid gebruik huishoudings in ONA ander alternatiewe energiebronne, soos om brandhout te koop of om vars hout te saag, in plaas van om dooie hout te versamel. Die studie het ‘n skakel gevind tussen brandhout gebruik en die gehalte en hoeveelheid wat beskikbaar is. Huishoudings het hulle brandhout verbruik aangepas by die seisoen, aanvraag en beskikbaarheid van brandhout. Die gemiddelde weeklikse brandhout verbruik per huishouding het gewissel tussen 66 kg tot 79 kg vir 'n area met ‘n oorvloed van brandhout en 59 kg tot 67 kg vir 'n gebied met 'n tekort aan brandhout. Mopanie was die mees gewilde spesie as gevolg van sy besikibaarheid en vermoë om doeltreffendheid te brand. Houtskaarstes beinvloed huishoudings op ekonomies, kulturele en voedings vlakk. De studie het bevind dat huishoudings in ’n area met ‘n houtskaarste gemiddeld N$50 per week spandeer om brandhout te koop en dat baie huishoudings afhanklik is van staatstoelaes en klein kontant inkomste-aktiwiteite. Die studie het gevind dat die regering, deur middel van die Ministerie van Landbou, Water en Bosbou, probeer om landelike huishoudings se energie gebruik te verbeter deur die bou van brandhout afsetpunte. Die studie het tot die gevolgtrekking gekom dat daar 'n hoë vlak van onwettige handel in brandhout is wat sal vereis dat die regering die aantal amptenare in die streek moet vermeerder en sy beleid rakende handel oor landsgrense heen moet verbeter. Daar is 'n wanbalans in die gebruik van brandstofspesies in 'n gebied met baie biomassa, en oorbenutting van hulpbronne in gedegradeerde gebiede. Die Direktoraat van Bosbou moet die gemeenskape oplei oor die waarde van ander moontlike brandstofspesies en die impak van die oes van lewendige bome op huishoudings se lewensbestaan en op die omgewing.

Oliver Tambo Institute of Governance and Policy Studies / MPM

Fuelwood is a basic need for rural households in Malawi. However, deforestation has reduced the quantity of forest products such as fuelwood available to households. This has negatively affected rural Malawian quality of life, especially for women who are forced to walk long distances to collect fuelwood, prepare foods with short cooking times, or reduce the number of meals. The Malawi government has encouraged the establishment of household owned woodlots, as a part of reforestation programs, to address the supply side of the forest product scarcity. However, fuelwood supply and use is also a gender-based issue; men plant trees and make decisions over harvesting, while women gather and use fuelwood. Within the household, woodlot products also have multiple and competing uses between men and women. It is critical to examine how gender dynamics affect women's fuelwood procurement and use from the woodlot. This study investigated how gender of the household head and women's access to woodlots affects fuelwood shortage, controlling for number of trees, household size, and use of other fuels. Fifty-one female and sixty-three male-headed households with household owned woodlots were interviewed, using questionnaire and focus group interviews. Results show that one-third of both household types reported experiencing fuelwood shortages in the past year. Logistic regression indicates that gender of household head is an important factor, along with number of trees in the woodlot, in determining fuelwood sufficiency. Female-headed households were less likely to experience fuelwood shortage than male-headed households when the interaction with number of trees was included. Whether a woman in male-headed households must seek permission to harvest fuelwood, number of trees, and cooking with maize stalk were factors that predicted fuelwood shortage. Suggestions for several interventions to address fuelwood supply and access were included. Planting more trees in woodlots and use of fuelwood efficient stoves are two important strategies. It is important to address gender-specific priorities as they relate to woodlot use. This can be done through gender sensitizations that target program planners and male household heads. For successful programs, men and women should participate in both program planning and implementation. / Graduation date: 2003