Engineering Commons^™

Cleavage Of Acetyl Groups For Acetic Acid Production In Kraft Pulp Mills, Ravikant Amogisidha Patil

Electronic Theses and Dissertations

The objective of this thesis was to determine appropriate conditions for cleavage of acetyl groups from northeast hardwood. Currently, acetyl groups end up in a waste product stream in most wood based pulp mills and thus are underutilized. Recently, a techno‐economic analysis was published that evaluated the suitability of the ‘Near‐Neutral Extraction’ process for recovery of acetic acid and ethanol in Kraft pulp mills. The results showed that the proposed process suffered from high capital investment and a low rate of return on investment. Additionally, the revenues generated by the sale of acetic acid were two times greater than the …

Career: A New Class Of Modified Mesoporous Silica Membranes With Controlled Pore Size And Surface Functionalization Through Unique Synthetic Approaches, William J. Desisto

University of Maine Office of Research Administration: Grant Reports

Artificial membranes made from sand-like materials known as silica are potentially more energy efficient than other separation processes such as distillation (change in phase from liquid to gas) because there is no phase change required to perform the separation. In addition, the opportunity exists for combining reaction and separation within a single unit using membrane reactors, thereby increasing yield on thermodynamically-limited reactions. However, the fabrication of high-quality silica membranes with pore size control and surface chemistry control remains challenging because of the inherent limits of existing synthetic approaches used to fabricate silica membranes. The researchers at the University of Maine …

Chemically Enhanced Water Removal In Papermaking, James John Beaupré

Electronic Theses and Dissertations

This work examines the utilization of chemical means to enhance the amount of water removed in the papermaking process prior to the application of heat. Through wet end application of a cationic surfactant, a significant increase in the amount of water removed in the forming and pressing sections is observed. This results in a reduction in the energy required to thoroughly dry the paper.

A variety of compounds hypothesized to potentially enhance dewatering were examined. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), produced significant enhanced dewatering via addition to a pulp slurry. Extensive bench top testing characterized the extent of reduction …

Synthesis And Characterization Of Mesoporous Silica Membranes Modified By Atomic And Molecular Layer Deposition, David Emmett Cassidy

Electronic Theses and Dissertations

Inorganic membranes offer a means for chemical separations in a variety of applications including chemical processing, drug delivery systems, battery separators and fuel cells. There is currently a “pore size gap” in silica membranes between 1-2 nanometers. Synthesizing membranes with a fine control of the pore size and distribution within that gap is a significant challenge. This thesis reports findings on using atomic and molecular layer deposition as new synthesis approaches to controlling pore size and chemical functionality of silica membranes. Mesoporous silica membranes, prepared using surfactant-templates with pore diameters ~4nm, were modified using atomic layer deposition and molecular layer …

Goali: Multicomponent Molecular Transport In Nanoporous Materials, Douglas M. Ruthven, David Sholl, Ronald Chance

University of Maine Office of Research Administration: Grant Reports

In recent years novel diffusion controlled catalytic processes and non-conventional separation processes such as adsorption and membrane processes have gained an increasingly important place in the petroleum and petrochemicals industries. Several factors have driven this trend, including the need to improve the energy efficiency and throughput of refineries, stricter limits on the allowable composition of gasoline and diesel fuel requiring the removal of aromatics and sulfur containing compounds to extremely low levels, the need to process increasingly complex deposits of both natural gas and liquid hydrocarbons, and the possibility of producing liquid fuels from non-traditional sources such as biomass. Although …