Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 128-137). Also available via the Internet.

Thesis (M. For. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 46-47). Also available via the World Wide Web.

Weyerhaeuser's Paper Mill in Albany, Oregon has been experiencing frequent ring formation in the #3 rotary lime kiln. Rings form when lime mud (CaCO₃) or product lime (CaO) particles adheres to the walls of the lime kiln and become resistant to the abrasive action of the sliding motion of product lime particles (Notidis, 1994). Ring formation has resulted in frequent shut downs to remove (blast) the rings and caused a significant loss of productivity and revenue to the company. A careful analysis of the production process in the mill revealed that concentration of sodium was high and that of sulfur low in the lime mud. The high sodium was due to the low sulfur input to the kiln resulting in high sodium to sulfur ratio. The use of natural gas as a fuel source in the kiln partly causes low sulfur levels in the mud. This study examines the effects of burning emulsified sulfur in the #3 rotary lime kiln to reduce sodium enrichment in the solids, and examine its effect on kiln operation and SO₂ emissions from the #3 rotary lime kiln. A four day trial of burning emulsified sulfur to reduce sodium concentration in the #3 rotary lime kiln was planned. Tote bins of 70% solution of emulsified sulfur was fed into the #3 rotary lime kiln. The sulfur feed was controlled to ensure an excess of sulfur by observing the SO₂ concentration in the kiln stack and maintaining a concentration above 100 ppm corrected to 10% oxygen. The results show that while burning emulsified sulfur had no significant effect on kiln operation, it resulted in a high reduction of sodium in the dust caught in the electrostatic precipitator and an increase SO₂ emission from the stack. The reduction of sodium in the dust was 50%, which is an enrichment factor of 2. Although lime can effectively remove SO₂, the removal efficiency decreased from 96.0% to 73.0% when emulsified sulfur was burned in the #3 rotary lime kiln. The results of this trial are promising, since it demonstrates that burning emulsified sulfur significantly lowers the sodium enrichment in the kiln. The reduced levels of sodium can potentially lead to a reduction in ring formation in the #3 rotary lime kiln in the Albany Paper Mill. / Graduation date: 2004

Thesis (M.S.)--Brigham Young University. Dept. of Chemical Engineering, 2006. / Includes bibliographical references (p. 75-78).

Life Cycle Assessment (LCA) is a tool for the evaluation of environmental impacts of a / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2007.

A series of process design and economics models have been created which calculate the process cost for several scenarios in steam-explosion/fractionation of wood. Steam -explosion pulping may prove to be an alternative to currently practiced standard pulping processes which require large capital investments, cause significant environmental problems, and produce a narrow range of products. In addition, steam-explosion/fractionation technology may offer the opportunity to produce chemicals and materials from biomass at a lower raw material and process cost than the alternative petrochemical feedstocks. The models are a series of modular computer simulations, where each module summarizes a particular group of unit operations with respect to mass balance, energy requirements, and process cost including utilities, capital, labor, and other related costs. These modules are compiled into 3 groups of scenarios: 1) unprocessed steam-exploded wood for use as enzyme! acid hydrolysis feedstock, hardboard production, or as unbleached pulp, 2) water extracted steam-exploded wood for recovery of pentosan polysaccharides and a lignocellulosic fiber, and 3) water and aqueous solvent (alkali or ethanol) extracted steam -exploded wood for recovery of pentosan polysaccharides, lignin polymers, and a cellulose -rich, unbleached fiber. For the base case evaluated, the cost of producing a 50% moisture, based on total weight, steam-exploded fiber is the raw material cost, dry basis, plus 3.5 cents! Lb of raw material consumed, dry basis. For Southwestern Virginia hardwoods at 2 cents/Lb ($40 per ton), dry basis, the total process cost is 5.5 cents/ Lb. / Master of Science

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Thesis (M.S.)--Virginia Polytechnic Institute, 1961. / Vita. Abstract. Includes bibliographical references (leaves 83-89). Also available via the Internet.

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