Earth's surface fluid variations and deformations from GPS and GRACE in global warming

Global warming is affecting our Earth's environment. For example, sea level is rising with thermal expansion of water and fresh water input from the melting of continental ice sheets due to human-induced global warming. However, observing and modeling Earth's surface change has larger uncertainties in the changing rate and the scale and distribution of impacts due to the lack of direct measurements. Nowadays, the Earth observation from space provides a unique opportunity to monitor surface mass transfer and deformations related to climate change, particularly the global positioning system (GPS) and the Gravity Recovery and Climate Experiment (GRACE) with capability of estimating global land and ocean water mass. In this paper, the Earth's surface fluid variations and deformations are derived and analyzed from global GPS and GRACE measurements. The fluids loading deformation and its interaction with Earth system, e.g., Earth Rotation, are further presented and discussed.Comment: Proceeding of Geoinformatics, IEEE Geoscience and Remote Sensing Society (GRSS), June 24-26, 2011, Shanghai, Chin

Supply chain design and operational planning models for biomass to drop-in fuel production

Renewable fuel is playing an increasingly important role as a substitute for fossil based energy. The US Department of Energy (DOE) has identified pyrolysis based platforms as promising biofuel production pathways. In this paper, we present a general biofuel supply chain model with a Mixed Integer Linear Programming (MILP) methodology to investigate the biofuel supply chain facility location, facility capacity at strategic levels, and biofuel production decisions at operational levels. In the model, we accommodate different biomass supplies and biofuel demands with biofuel supply shortage penalty and storage cost. The model is then applied to corn stover fast pyrolysis pathway with upgrading to hydrocarbon fuel since corn stover is the main feedstock for second generation biofuel production in the US Midwestern states. Numerical results illustrate unit cost for biofuel production, biomass, and biofuel allocation. The case study demonstrates the economic feasibility of producing biofuel from biomass at a commercial scale in Iowa

Techno-economic analysis of advanced biofuel production based on bio-oil gasification

This paper evaluates the economic feasibility of a hybrid production pathway combining fast pyrolysis and bio-oil gasification. The conversion process is simulated with Aspen Plus® for a 2000 t d-1 facility. Techno-economic analysis of this fast pyrolysis and bio-oil gasification pathway has been conducted to assess the economic feasibility. A total capital investment of $438 million has been estimated and the minimum fuel selling price (MSP) is$5.6 per gallon of gasoline equivalent. The sensitivity analysis shows that the MSP is most sensitive to internal rate of return, fuel yield, biomass feedstock cost, and fixed capital investment. Monte-Carlo simulation shows that MSP for bio-oil gasification would be more than $6/gal with a probability of 0.24, which indicates this pathway is still at high risk with current economic situation

Life cycle assessment of the production of hydrogen and transportation fuels from corn stover via fast pyrolysis

This life cycle assessment evaluates and quantifies the environmental impacts of the production of hydrogen and transportation fuels from the fast pyrolysis and upgrading of corn stover. Input data for this analysis come from Aspen Plus modeling, a GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model database and a US Life Cycle Inventory Database. SimaPro 7.3 software is employed to estimate the environmental impacts. The results indicate that the net fossil energy input is 0.25 MJ and 0.23 MJ per km traveled for a light-duty vehicle fueled by gasoline and diesel fuel, respectively. Bio-oil production requires the largest fossil energy input. The net global warming potential (GWP) is 0.037 kg CO2eq and 0.015 kg CO2eq per km traveled for a vehicle fueled by gasoline and diesel fuel, respectively. Vehicle operations contribute up to 33% of the total positive GWP, which is the largest greenhouse gas footprint of all the unit processes. The net GWPs in this study are 88% and 94% lower than for petroleum-based gasoline and diesel fuel (2005 baseline), respectively. Biomass transportation has the largest impact on ozone depletion among all of the unit processes. Sensitivity analysis shows that fuel economy, transportation fuel yield, bio-oil yield, and electricity consumption are the key factors that influence greenhouse gas emissions

Techno-economic analysis of fast pyrolysis and upgrading facilities employing two depolymerization pathways

We evaluate the economic feasibility of fast pyrolysis and upgrading facilities 11 employing either of two depolymerization pathways: two-stage hydrotreating 12 followed by a FCC (fluid catalytic cracking) stage or single-stage hydrotreating 13 followed by a hydrocracking stage. In the hydrotreating/FCC pathway, two options 14 are available as the hydrogen source for hydrotreating: merchant hydrogen or 15 hydrogen from natural gas reforming. The primary products of the hydrotreating/FCC 16 pathway are commodity chemicals whereas the primary products for the 17 hydrotreating/hydrocracking pathway are transportation fuels and hydrogen. The two 18 pathways are modeled using Aspen Plus® for a 2000 metric tons/day facility. 19 Equipment sizing and cost calculations are based on Aspen Economic Evaluation® 20 software. 21 The fast pyrolysis bio-oil yield is assumed to be 65% of biomass. We calculate the 22 internal rate of return (IRR) for each pathway as a function of feedstock cost, fixed 23 capital investment (FCI), hydrogen and catalyst costs, and facility revenues. The 24 results show that a facility employing the hydrotreating/FCC pathway with hydrogen 25 production via natural gas reforming option generates the highest IRR of 13.3%. 26 Sensitivity analysis demonstrates that product yield, FCI, and biomass cost have the 27 greatest impacts on facility IRR. Monte-Carlo analysis shows that two-stage hydrotreating and FCC of the aqueous phase bio-oil with hydrogen produced via 1 natural gas reforming has a relatively low risk for project investment

Techno-economic analysis of biobased chemicals production via integrated catalytic processing

We evaluate the economic feasibility of a fast pyrolysis facility producing biobased commodity chemicals based on various manifestations of Integrated Catalytic Processing (ICP). Five scenarios are analyzed: fluid catalytic cracking (FCC) of whole pyrolysis oil (WPO); one-stage hydrotreating and FCC of WPO; FCC of the aqueous phase of pyrolysis oil (APPO); one-stage hydrotreating and FCC of the APPO; and two-stage hydrotreating followed by FCC of the APPO. We calculate the internal rate of return (IRR) for each scenario as functions of the costs of feedstock, hydrogen, and catalyst, and projected revenues for the facility. The assumed feedstock cost is $83/MT for mixed wood. The assumed hydrogen cost is$3/kg. Catalyst costs are based on December 2010 prices and projected revenues are based on August 2010 petrochemical prices. The analysis indicates that a facility employing FCC of WPO or APPO without hydrotreating is unable to generate a positive IRR. Employment of two-stage hydrotreating significantly increases the facility IRR, although IRRs in excess of 10% are only attained when higher pyrolysis oil yields (70 wt%) are assumed

Comparative techno-economic analysis of biohydrogen production via bio-oil gasification and bio-oil reforming

This paper evaluates the economic feasibility of biohydrogen production via two bio-oil processing pathways: bio-oil gasification and bio-oil reforming. Both pathways employ fast pyrolysis to produce bio-oil from biomass stock. The two pathways are modeled using Aspen Plus® for a 2000 t d-1 facility. Equipment sizing and cost calculations are based on Aspen Economic Evaluation® software. Biohydrogen production capacity at the facility is 147 t d-1 for the bio-oil gasification pathway and 160 t d-1 for the bio-oil reforming pathway. The biomass-to-fuel energy efficiencies are 47% and 84% for the bio-oil gasification and bio-oil reforming pathways, respectively. Total capital investment (TCI) is 435 million dollars for the bio-oil gasification pathway and is 333 million dollars for the bio-oil reforming pathway. Internal rates of return (IRR) are 8.4% and 18.6% for facilities employing the bio-oil gasification and bio-oil reforming pathways, respectively. Sensitivity analysis demonstrates that biohydrogen price, biohydrogen yield, fixed capital investment (FCI), bio-oil yield, and biomass cost have the greatest impacts on facility IRR. Monte-Carlo analysis shows that bio-oil reforming is more economically attractive than bio-oil gasification for biohydrogen production