Mass Balance, Energy, and Exergy Analysis of Bio-Oil Production by Fast Pyrolysis

Abstract

Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture (USDA). USDA is an equal opportunity provider and employer. Mass, energy, and exergy balances are analyzed for bio-oil production in a bench-scale fast pyrolysis system developed by the USDA's Agricultural Research Sen'ice (ARS) for the processing of commodity crops to fuel intermediates. Because mass balance closure is difficult to achieve due, in part, to the system's small size and complexity a linear programming optimization model is developed to improve closure of elemental balances without losing the overall representation of the pyrolysis products. The model results provide an opportunity to analyze true energy and exergy balances for the system. While energy comparisons are based on heating values, exergy flows are computed using statistical relationships and other standard techniques. Comparisons were made for a variety of biomass feedstocks including energy crops and various byproducts of agriculture and bioenergy industiy. The mass model allows for proper accounting of sources of mass loss and suggestions for improved system performance. Energy recovery and exergetic efficiency are compared for a variety of pyrolysis product utilization scenarios including use of biochar and noncondensable gases as heat sources. Exergetic efficiencies show high potential for energy utilization when all the pyrolysis product streams can be recycled to recuperate their internal energy. The exergy analysis can be beneficial to developing exergetic life cycle assessments (ELCA) for the fast pyrolysis process as sustainable technology for advanced biofuels production.

Exergoeconomic assessment of CHP-integrated biomass upgrading

“…Comparably high exergetic efficiencies for the torrefaction and the fast pyrolysis process have been reported in Refs. [7,28]. The Table 5a CHP plant exergoeconomic analysis.…”

“…[6][7][8][9], among others. Depending on feedstock and product definition, the exergetic efficiency of the biomass fast pyrolysis process was found to vary widely between 52% and 94% [6,7].…”

“…[6][7][8][9], among others. Depending on feedstock and product definition, the exergetic efficiency of the biomass fast pyrolysis process was found to vary widely between 52% and 94% [6,7]. Rogers and Brammer [8] stated the production of bio-oil to be profitable at the current oil price level which is in line with the recent commissioning of the CHP-integrated pyrolysis oil production plant in Joensuu, Finland by Fortum [9].…”

Energy and exergy analyses of sewage sludge thermochemical treatment

“…There are different ways to address the energy balances. Boateng et al [12] evaluated the energy analysis of the production of bio-oil by fast pyrolysis in terms of calorific values. Recently, Hasokai et al [13] suggested an alternative approach, which involves the estimation of heating values based on the elemental composition of solid and liquid fractions.…”

Exergy analysis of a diesel engine fuelled with Aegle marmelos de‐oiled seed cake pyrolysis oil opus

“…However, it is similarly significant to allocate the quality to the energy 18 . The knowledge of “how the energy is missing” will assist in analyzing means to diminish the similar to increase the performance of the diesel engine in standings of engine output and efficiency 19 …”