TECHNO-ECONOMIC AND LIFE CYCLE ASSESSMENTS OF BIOFUEL PRODUCTION FROM WOODY BIOMASS THROUGH TORREFACTION-FAST PYROLYSIS AND CATALYTIC UPGRADING

Biofuel production through fast pyrolysis of biomass is a promising conversion route in the production of biofuels compatible with existing technology. The bio-oil produced from fast pyrolysis is a versatile feedstock that can be used as a heating oil or upgraded to a transportation hydrocarbon biofuel. Comparative study of a one-step, fast pyrolysis only pathway and a two-step torrefaction-fast pyrolysis pathway was carried out to evaluate the effect of torrefcation on (i) the minimum selling price of biofuel and (ii) the potential life cycle GHG emissions of the biofuel production pathway. To produce bio-oil which can serve as a substitute for heating oil from loblolly pine biomass feedstock, torrefaction at three different temperatures of 290, 310 and 330°C were investigated while fast pyrolysis occurred at 530°C. Three scenarios of producing process heat from natural gas, internal by-products biochar or torrefaction condensate were also investigated. Economic assessment showed more favorable economics for the two-step bio-oil production pathway relative to the one-step bio-oil production pathway. The lowest minimum selling price of $1.04/gal was obtained for a two-step pathway with torrefaction taking place at 330°C. The environmental impact assessment also showed more the two-step bio-oil production pathway to be more environmentally friendly. The lowest GWP of about -60g CO2eq was observed for the two-step pathway at torrefaction temperature of 330°C while GWP of about 36g CO2eq was observed for the one-step pathway. Relative to heavy fuel oil, the one-step and two-step pathways are more environmentally friendly with lower GWP. To produce hydrocarbon biofuel by the catalytic upgrade of bio-oil derived from fast pyrolysis of loblolly pine, three torrefaction temperatures of 290, 310 and 330°C were investigated with fast pyrolysis taking place at 530°C. Three scenarios of producing process heat from natural gas, internal by-products biochar or torrefaction condensate were investigated. The effect of heat integration was also examined. The economic assessment showed equal minimum selling price for the one-step hydrocarbon biofuel production pathway and a two-step pathway with torrefaction occurring at 290°C. A minimum selling price of$4.82/gal was estimated while higher torrefaction temperatures showed less favorable economics. The environmental impact assessment however showed the two-step pathway to be more environmentally friendly when compared with the one-step pathway. GWP of about -66g CO2eq was observed for the two-step pathway with torrefaction taking place at 330°C compared to a GWP of about 88g CO2eq obtained for the one-step. Further reduction in minimum selling price and GWP were observed with heat integration. A minimum selling price of about $4.01/gal was estimated for the one-step and two-step pathway with torrefaction taking place at 290°C while GWP of about -144 g CO2eq was observed for the two-step hydrocarbon biofuel with torrefaction temperature of 330°C

Carbon nanotube supported platinum-palladium nanoparticles for formic acid oxidation

Pt, Pd and PtxPdy alloy nanoparticles (Pt1Pd1, Pt1Pd3, atomic ratio of Pt to Pd is 1:1, 1:3, respectively) supported on carbon nanotube (CNT) with high and uniform dispersion were prepared by a modified ethylene glycol method. Transmission electron microscopy images show that small Pt and PtxPdy nanoparticles are homogeneously dispersed on the outer walls of CNT, while Pd nanoparticles have some aggregations and comparatively larger particle size. The average particle sizes of Pt/CNT, Pt1Pd1/CNT, Pt1Pd3/CNT and Pd/CNT obtained from the Pt/Pd (2 2 0) diffraction peaks in the X-ray diffraction patterns are 2.0, 2.4, 3.1 and 5.4 nm, respectively. With increasing Pd amount of the catalysts, the mass activity of formic acid oxidation reaction (FAOR) on the CNT supported catalysts increases in both cyclic voltammetry (CV) and chronoamperometry (CA) tests, although the particle size gets larger (thus, the relative surface area gets smaller). The CV study indicates a \u27direct oxidation pathway\u27 of FAOR occurred on the Pd surface, while on the Pt surface, the FAOR goes through \u27COads intermediate pathway\u27. Pd/CNT demonstrates 7 times better FAOR mass activity than Pt/CNT (2.3 mA/mgPd vs. 0.33 mA/mgPt) at an applied potential of 0.27 V (vs. RHE) in the CA test. © 2010 Elsevier Ltd. All rights reserved

Techno-economic assessment of the effect of torrefaction on fast pyrolysis of pine

Techno-economic assessment of bio-oil production from fast pyrolysis of pine was explored through process simulation. In this work, bio-oil production via a one-step pyrolysis route and a two-step pyrolysis which included a torrefaction step before fast pyrolysis were modeled to process 1000 MT/day of dry feed (dry basis) through the pyrolyzer at a temperature of 530 °C while two-step -pyrolysis was investigated at three different torrefaction temperatures of 290, 310, and 330 °C. Different scenarios that included the use of fossil energy to produce process heat as well as use of renewable energy either through the combustion of char or a portion of the condensates from -torrefaction were also investigated. Economic analysis indicates that a torrefaction step results in a reduction in the minimum selling price of bio-oil produced which reduced further with -torrefaction -temperature with lowest bio-oil price of $1.04/gal obtained for a two-step pyrolysis at torrefaction -temperature of 330 °C in comparison to$1.32/gal for a one-step process. Minimum selling price of bio-oil on an energy basis however suggests a higher price of about $22.19/GJ for a two-step in -comparison to$16.89/GJ for a one-step. There could be a trade-offs between the higher quality and the higher selling price considering the downstream upgrade step to hydrocarbon fuel

System analyses of high-value chemicals and fuels from a waste high-density polyethylene refinery. Part 2: Carbon footprint analysis and regional electricity effects

The growing generation of plastic waste (PW) is placing severe burdens in the terrestrial and marine environments due to its inappropriate management at end of life. Governments are aware of this situation and have proposed production bans or initiatives to minimize the amount of PW that is landfilled and encourage recycling or energy recovery. Circular economy is a strategy that reuses PW to produce new polymers while avoiding its disposal and displacing the use of virgin materials. This study reports on a refinery design that employs fast pyrolysis of waste high-density polyethylene and downstream separations to obtain monomers, aromatics, and hydrocarbon fuels. This study focuses on a life cycle carbon footprint analysis (CFA) and the effects of regional electricity grids on cradle-to-gate greenhouse gas emissions using process simulation for life cycle assessment inputs. The effects of heat integration on greenhouse gas (GHG) emissions were investigated in scenarios, as well as the investigation of parameter sensitivity and uncertainty. The CFA results show that the GHG emissions of ethylene, propylene, and aromatics mixture (1.08, 1.10, and 1.16 kg CO2 equiv/kg, respectively) are equal to or less than those of fossil products when heat integration is included assuming U.S. average electricity grid. The evaluation of regional electricity grids on GHG emissions for all products was conducted for 50 states in the U.S

Production of Hydrocarbon Fuel Using Two-Step Torrefaction and Fast Pyrolysis of Pine. Part 1: Techno-economic Analysis

As part I of two companion papers, the present paper evaluates the economic feasibility of hydrocarbon biofuel production via two pathways: a one-step production pathway through fast pyrolysis of biomass followed by the catalytic upgrade of bio-oil to a liquid hydrocarbon biofuel and a novel two-step pathway that includes a torrefaction pretreatment step prior to fast pyrolysis and then the catalytic upgrade. These two pathways were modeled using Aspen Plus to process 1000 dry metric tons/day of feed through the fast pyrolysis unit operating at 530 °C whereas torrefaction for the two-step pathway was investigated at three different torrefaction temperatures of 290, 310, and 330 °C. Three scenarios of producing process heat from natural gas, internal byproducts biochar supplemented with natural gas, and torrefaction condensate were investigated, with additional heat integration considered. Minimum selling price ranged from $4.01/gal to$4.78/gal for the heat-integrated processes whereas the price ranged from $4.70/gal to$6.84/gal without heat integration. Analysis indicated that a one-step pathway and a two-step pathway with torrefaction taking place at 290 °C yielded comparable least minimum selling price and it increased with increasing torrefaction temperature. Sensitivity analysis showed that the yield of hydrocarbon biofuel, total project investment, and internal rate of return have the greatest impact

System analyses of high-value chemicals and fuels from a waste high-density polyethylene refinery. Part 1: Conceptual design and techno-economic assessment

The increasing amount of plastic waste generation has become an important concern for the chemical industry and government agencies due to high disposal and environmental leakage rates. Chemical recycling is a promising technology due to the potential reduction of pollutant emissions and the establishment of a circular economy through the production of monomers and fuels. However, there is scarce information on industrial scale processes of this technology and their energetic, economic, and environmental performance. Therefore, the present process modeling study presents a novel multiproduct pyrolysis-based refinery for the conversion of 500 tonnes/day of waste high-density polyethylene (HDPE). The products obtained from the modeled refinery were chemical grade ethylene and propylene, an aromatics mixture, and low- and high-molecular weight hydrocarbon mixtures (MWHCs). Part 1 of this study focuses on the energetic and economic evaluation of the refinery and the potential effects of heat integration. The energy efficiency was 68% and 73% for the base case and the heat integrated refinery, respectively. The net present values (NPVs) were 367 and 383 million U.S. dollars (MM USD), for the base case and the heat integrated process, respectively. These results suggest energetic and economic sustainability of the design and its promising application on an industrial scale

Update to effect of Temperature and Vapor Residence Time on the Micropyrolysis Products of Waste High Density Polyethylene

A previously published paper presented product composition results in peak area percentage following pyrolysis of waste high-density polyethylene experiments in a two-stage micropyrolysis reactor. Pyrolysis experiments were performed at 625, 650, and 675 °C with vapor residence times (VRTs) varying from 1.4 to 5.6 s (Gracida-Alvarez, U. R.; et al. Ind. Eng. Chem. Res. 2018, 57, 1912-1923). This brief communication discusses the methods used to convert gas chromatography/mass spectrometry (GC/MS) peak areas to mass results and provides a brief analysis of product mass compositions. Product mass composition provides valuable information for future work and comparison to studies reporting product yields in mass units. The mass fractions of gas products and aromatics were found to increase with both temperature and VRT, while liquid and wax fractions declined

Effects of Coproduct Uses on Environmental and Economic Sustainability of Hydrocarbon Biofuel from One- and Two-Step Pyrolysis of Poplar

This study investigated the environmental and economic sustainability of liquid hydrocarbon biofuel production via fast pyrolysis of poplar biomass through two pathways: a one-step pathway that converted poplar via fast pyrolysis only, and a two-step pathway that includes a torrefaction step prior to fast pyrolysis. Optimization of these fast pyrolysis-based biofuel processes were investigated through heat integration and alternative uses of the coproduct biochar, which can be sold as an energy source to displace coal, soil amendment or processed into activated carbon. The impacts of optimization on the cost of hydrocarbon biofuel production as well as the environmental impacts were investigated through a technoeconomic analysis (TEA) and life cycle assessment (LCA), respectively, with two-step and one-step processing compared to fossil fuels. The TEA indicates that a one-step heat integrated pathway with the production of activated carbon has a minimum selling price of $3.23/gallon compared to$5.16/gallon for a two-step heat integrated process with burning of the coproduct biochar to displace coal. The LCA indicates that using the displacement analysis approach, a two-step heat integrated pathway had a global warming potential of −102 g CO₂ equivalent/MJ biofuel compared to 16 CO₂ equivalent/MJ biofuel for the heat integrated one-step pathway

Carbon Footprint Analysis of Gasoline and Diesel from Forest Residues and Algae using Integrated Hydropyrolysis and Hydroconversion Plus Fischer-Tropsch (IH \u3c sup\u3e 2 \u3c/sup\u3e Plus cool GTL)

© 2018 American Chemical Society. Life cycle analysis was conducted with a focus on greenhouse gas (GHG) emissions of renewable gasoline and diesel produced by the integrated hydropyrolysis and hydroconversion (IH2) and the new IH2 plus Fischer-Tropsch (IH2 Plus cool GTL) processes. This new process has a primary objective of increasing the yield of biofuel relative to original IH2 process (increase of 26% to 38% wt) by processing the C1-C3 gas co-products through an integrated Fischer-Tropsch unit to produce liquid-range hydrocarbon biofuel. For both biofuel processes, woody biomass residues (forest logging and saw mills) and algae were investigated as feedstocks. The effect of the electricity generation mix of different states in the U.S. was also examined for algae cultivation. For woody residues as feedstock, life cycle GHG emission savings of about 86.8% and 63.3% were calculated for the IH2 and optimized-IH2 Plus cool GTL hydrocarbon biofuel, respectively, relative to fossil-derived fuel. For algae as feedstock, emission increases of about 140% and 103% were calculated for the IH2 and optimized-IH2 Plus cool GTL, respectively, relative to fossil-derived fuel. The electricity grid mix of the biorefinery location significantly impacts the GHG emissions of the processes for algae feedstock. GHG savings of about 42% can be potentially achieved if the plant was located in an area with a low GHG intensity grid. This study has shown that a significant biofuel yield boost can be achieved while retaining high GHG savings by using IH2 Plus cool GTL for a woody feedstock

Production of Hydrocarbon Fuel Using Two-Step Torrefaction and Fast Pyrolysis of Pine. Part 2: Life-Cycle Carbon Footprint

This study, as part II of two companion papers, investigated the environmental performance of liquid hydrocarbon biofuel production via fast pyrolysis of pine through two pathways: a one-step pathway via fast pyrolysis only, and a two-step pathway that includes a torrefaction step prior to fast pyrolysis. Fast pyrolysis in all cases took place at a temperature of 530 °C whereas for the two-step pathways, torrefaction was investigated at temperatures of 290, 310, and 330 °C. Bio-oil produced was then catalytically upgraded to hydrocarbon biofuel. Different scenarios for providing the required process heat either by using fossil energy or renewable energy, as well as the effect of heat integration, were also investigated. Our life cycle analysis indicated that using the energy allocation approach, a two-step heat integrated pathway with torrefaction taking place at 330 °C had the lowest global warming potential among all scenarios of about 29.0 g CO₂ equiv/MJ biofuel. Using the system expansion approach, significantly higher reductions in GHG emissions of about 56 to 265% relative to conventional gasoline were observed for the heat integrated processes. More modest percentage reduction in emissions of about 34 to 67% was observed across all scenarios using the energy allocation approach