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Abstract Lignin is considered as a renewable and sustainable resource for producing value-added aromatic chemicals and functional carbon materials. Herein, we develop a one-step catalyst-free depolymerization strategy to convert lignin into aryl monomers and carbon nanospheres simultaneously. Importantly, microwave-assisted depolymerization (MAD) in conjunction with dichloromethane (CH2Cl2) vapors is developed. The total mass yield of guaiacols reached the highest amount of 225.1 mg/g at 600 °C, and the highest yields of phenols (49.0 mg/g) and aromatic hydrocarbons (155.1 mg/g) were obtained at 700 °C. Hydrogen radicals and hydrogen chloride (HCl) are in-situ formed from CH2Cl2, significantly decreasing the activation barrier and reforming pyrolysis vapors to promote the formation of aryl monomers. Interestingly, uniform carbon nanospheres with an average size of 140 nm were produced as co-products at 700 °C. The microwave “hot-spots”, allied with the continuous surface erosion and the decrease in surface energy of lignin-derived carbon precursors by CH2Cl2 vapor, can be considered the driving force for the ultimate formation of carbon nanospheres. The CH2Cl2/MAD system produces aryl monomers (26.8 wt% yield) and carbon nanospheres (36.6 wt% yield) at 700 °C. We provide a facile, intriguing and scalable approach to convert lignin to valuable aryl monomers and sustainable carbon materials that can be applied in the chemistry, energy and environmental fields.

Abstract Lignin is considered as a renewable and sustainable resource for producing value-added aromatic chemicals and functional carbon materials. Herein, we develop a one-step catalyst-free depolymerization strategy to convert lignin into aryl monomers and carbon nanospheres simultaneously. Importantly, microwave-assisted depolymerization (MAD) in conjunction with dichloromethane (CH2Cl2) vapors is developed. The total mass yield of guaiacols reached the highest amount of 225.1 mg/g at 600 °C, and the highest yields of phenols (49.0 mg/g) and aromatic hydrocarbons (155.1 mg/g) were obtained at 700 °C. Hydrogen radicals and hydrogen chloride (HCl) are in-situ formed from CH2Cl2, significantly decreasing the activation barrier and reforming pyrolysis vapors to promote the formation of aryl monomers. Interestingly, uniform carbon nanospheres with an average size of 140 nm were produced as co-products at 700 °C. The microwave “hot-spots”, allied with the continuous surface erosion and the decrease in surface energy of lignin-derived carbon precursors by CH2Cl2 vapor, can be considered the driving force for the ultimate formation of carbon nanospheres. The CH2Cl2/MAD system produces aryl monomers (26.8 wt% yield) and carbon nanospheres (36.6 wt% yield) at 700 °C. We provide a facile, intriguing and scalable approach to convert lignin to valuable aryl monomers and sustainable carbon materials that can be applied in the chemistry, energy and environmental fields.

Three plant species included among the Nevada Threatened or Endangered Flora of the Federal Register list of July 1, 1975, were omitted from the recent reports dealing with these groups of plants in central-southern Nevada. Two of the species, Ephedra funerea and Mirabilis pudica, were not included because they are both widely distributed and locally common in southern Nevada and were understood (unofficially) to be no longer considered candidates for either an Endangered or Threatened status. The third species, Machaeranthera ammophila, is now included with M. arida, an uncommon species of central and eastern Mojave Desert of southern California (to southern Nevada, Arizona, and Sonora), and is therefore no longer a candidate for the status of Threatened Species in Nevada.

Three plant species included among the Nevada Threatened or Endangered Flora of the Federal Register list of July 1, 1975, were omitted from the recent reports dealing with these groups of plants in central-southern Nevada. Two of the species, Ephedra funerea and Mirabilis pudica, were not included because they are both widely distributed and locally common in southern Nevada and were understood (unofficially) to be no longer considered candidates for either an Endangered or Threatened status. The third species, Machaeranthera ammophila, is now included with M. arida, an uncommon species of central and eastern Mojave Desert of southern California (to southern Nevada, Arizona, and Sonora), and is therefore no longer a candidate for the status of Threatened Species in Nevada.

This document is the final report of work on a project concerned with the fragmentation of char particles during pulverized coal combustion that was conducted at the High Temperature Gasdynamics Laboratory at Stanford University, Stanford, California. The project is intended to satisfy, in part, PETC`s research efforts to understand the chemical and physical processes that govern coal combustion. The overall objectives of the project were: (1) to characterize the fragmentation events as a function of combustion environment, (2) to characterize fragmentation with respect to particle porosity and mineral loadings, (3) to assess overall mass loss rates with respect to particle fragmentation, and (4) to quantify the impact of fragmentation on unburned carbon in ash. The knowledge obtained during the course of this project can be used to predict accurately the overall mass loss rates of coals based on both the physical and chemical characteristics of their chars. The work provides a means of assessing reasons for unburned carbon in the ash of coal fired boilers and furnaces.

This document is the final report of work on a project concerned with the fragmentation of char particles during pulverized coal combustion that was conducted at the High Temperature Gasdynamics Laboratory at Stanford University, Stanford, California. The project is intended to satisfy, in part, PETC`s research efforts to understand the chemical and physical processes that govern coal combustion. The overall objectives of the project were: (1) to characterize the fragmentation events as a function of combustion environment, (2) to characterize fragmentation with respect to particle porosity and mineral loadings, (3) to assess overall mass loss rates with respect to particle fragmentation, and (4) to quantify the impact of fragmentation on unburned carbon in ash. The knowledge obtained during the course of this project can be used to predict accurately the overall mass loss rates of coals based on both the physical and chemical characteristics of their chars. The work provides a means of assessing reasons for unburned carbon in the ash of coal fired boilers and furnaces.

This engineering and economic study is concerned with the question of using the natural heat of the earth, or geothermal energy, as an alternative to other energy sources such as oil and natural gas which are increasing in cost. This document represents a quarterly progress report on the effort directed to determine the availability of geothermal energy within the Fort Peck Indian Reservation, Montana (Figure 1), and the feasibility of beneficial use of this resource including engineering, economic and environmental considerations. The project is being carried out by the Tribal Research office, Assinboine and Sioux Tribes, Fort Peck Indian Reservation, Poplar, Montana under a contract to the United States Department of Energy. PRC TOUPS, the major subcontractor, is responsible for engineering and economic studies and the Council of Energy Resource Tribes (CERT) is providing support in the areas of environment and finance, the results of which will appear in the Final Report. The existence of potentially valuable geothermal resource within the Fort Peck Indian Reservation was first detected from an analysis of temperatures encountered in oil wells drilled in the area. This data, produced by the Montana Bureau of Mines and Geology, pointed to a possible moderate to high temperaturemore » source near the town of Poplar, Montana, which is the location of the Tribal Headquarters for the Fort Peck Reservation. During the first phase of this project, additional data was collected to better characterize the nature of this geothermal resource and to analyze means of gaining access to it. As a result of this investigation, it has been learned that not only is there a potential geothermal resource in the region but that the producing oil wells north of the town of Poplar bring to the surface nearly 20,000 barrels a day (589 gal/min) of geothermal fluid in a temperature range of 185-200 F. Following oil separation, these fluids are disposed of by pumping into a deep groundwater aquifer. While beneficial uses may be found for these geothermal fluids, even higher temperatures (in excess of 260 F) may be found directly beneath the town of Poplar and the new residential development which is being planned in the area. This project is primarily concerned with the use of geothermal energy for space heating and domestic hot water for the town of Poplar (Figure 2 and Photograph 1) and a new residential development of 250 homes which is planned for an area approximately 4 miles east of Poplar along U.S. Route 2 (Figure 2 and Photograph 2). A number of alternative engineering design approaches have been evaluated, and the cost of these systems has been compared to existing and expected heating costs.« less

This engineering and economic study is concerned with the question of using the natural heat of the earth, or geothermal energy, as an alternative to other energy sources such as oil and natural gas which are increasing in cost. This document represents a quarterly progress report on the effort directed to determine the availability of geothermal energy within the Fort Peck Indian Reservation, Montana (Figure 1), and the feasibility of beneficial use of this resource including engineering, economic and environmental considerations. The project is being carried out by the Tribal Research office, Assinboine and Sioux Tribes, Fort Peck Indian Reservation, Poplar, Montana under a contract to the United States Department of Energy. PRC TOUPS, the major subcontractor, is responsible for engineering and economic studies and the Council of Energy Resource Tribes (CERT) is providing support in the areas of environment and finance, the results of which will appear in the Final Report. The existence of potentially valuable geothermal resource within the Fort Peck Indian Reservation was first detected from an analysis of temperatures encountered in oil wells drilled in the area. This data, produced by the Montana Bureau of Mines and Geology, pointed to a possible moderate to high temperaturemore » source near the town of Poplar, Montana, which is the location of the Tribal Headquarters for the Fort Peck Reservation. During the first phase of this project, additional data was collected to better characterize the nature of this geothermal resource and to analyze means of gaining access to it. As a result of this investigation, it has been learned that not only is there a potential geothermal resource in the region but that the producing oil wells north of the town of Poplar bring to the surface nearly 20,000 barrels a day (589 gal/min) of geothermal fluid in a temperature range of 185-200 F. Following oil separation, these fluids are disposed of by pumping into a deep groundwater aquifer. While beneficial uses may be found for these geothermal fluids, even higher temperatures (in excess of 260 F) may be found directly beneath the town of Poplar and the new residential development which is being planned in the area. This project is primarily concerned with the use of geothermal energy for space heating and domestic hot water for the town of Poplar (Figure 2 and Photograph 1) and a new residential development of 250 homes which is planned for an area approximately 4 miles east of Poplar along U.S. Route 2 (Figure 2 and Photograph 2). A number of alternative engineering design approaches have been evaluated, and the cost of these systems has been compared to existing and expected heating costs.« less

This report analyzes the capital and environmental cost of energy recovery from municipal sludge and feedlot manure. Literature on waste processing and energy conversion and interviews with manufacturers were used for baseline data for construction of theoretical models using three energy conversion processes: anaerobic digestion, incineration, and pyrolysis. Process characteristics, environmental impact data, and capital costs are presented in detail for each conversion system. The energy recovery systems described would probably be sited near large sources of sludge and manure, i.e., metropolitan sewage treatment plants and large feedlots in cattle-raising states. Although the systems would provide benefits in terms of waste disposal as well as energy production, they would also involve additional pollution of air and water. Analysis of potential siting patterns and pollution conflicts is needed before energy recovery systems using municipal sludge can be considered as feasible energy sources.