This article presents a detailed techno-economic analysis, under Norwegian conditions, for the production of biocrude from woody biomass via high temperature entrained flow gasification and Fischer−Tropsch (FT) synthesis with integrated coproduction of heat and electricity. Biomass pretreatment based on both conventional drying and torrefaction processes are considered as options. Maximum calculated efficiency of biocrude at lower and upper bound CO conversions of 40% and 80% at the gasifier operating conditions of lambda value 0.2 and temperature 1300°C are 27% and 44%, respectively. Under these conditions, maximum thermal and net electrical efficiency are 55% and 15.5%, respectively. The economic viability of the biocrude production for plant capacities in the range of 150−600 MW thermal input has been evaluated as a function of the type of biomass pretreatment, gasification operating conditions, and the heat to electricity production ratios. Results from the economic analysis show that coproduction of biocrude combined with 100% heat production for district heating gives the lowest biocrude cost under Norwegian conditions, with large variations as the electricity to heat production ratio increases.
We present in this paper simplified chemical mechanisms for gas phase biomass combustion based on automatic reduction of detailed and comprehensive kinetics. The reduction method that has been employed is a combined reaction flow and sensitivity analysis well-known to combustion, resulting in a necessity index ranking all chemical species for automatic reduction. The objective is to obtain more compact chemical models, so-called skeletal mechanisms, for implementation into computational fluid dynamics, CFD, in order to reduce computational time. In the current work, the physical system used for the development and validation of the chemical models is that of a tubular reactor, or plug flow reactor, with operating conditions typically found in biomass reactors. The focus has been on gas phase reactions only, and the fuel composition is based on experimental values from biomass and coal gasification. Emphasis has been on the reliability of the simplified models and the correct prediction of important emission parameters such as NO x and important intermediate species. The original chemical model, consisting of several sub models for important reaction paths known in biomass combustion, contained 81 species and 1401 reactions. This was successfully reduced down to 36 species, providing a compact and reliable chemical model for implementation into CFD. The model still contains the reaction paths of C 2 species, allowing for more realistic fuel gas compositions. The model has been experimentally validated for a wide range of temperatures including low temperature chemistry and reducing conditions for NO x . The computational time saved using the simplified models was significant with over 80% reduction in CPU time.
This work addresses
the process and economic performance
of the
production of gasoline and diesel range fuels from urban sewage sludge.
The overall production route involves direct conversion of the sewage
sludge to an intermediate oil phase, so-called biocrude, via hydrothermal
liquefaction at near-critical water conditions and further upgrading
of the biocrude based on conventional refinery processes. The overall
mass and energy yields of combined naphtha and middle distillate from
sewage sludge on dry basis are approximately 19 and 60%, where the
naphtha fraction represents about 45% of the total, with a minimum
fuel selling price ranging between 2.4 and 0.8 €/liter assuming
full investment in both the biocrude production and upgrading plant
with sewage sludge feed capacities in the range of 3 to 30 dry-ton/day.
If existing equipment at refinery can be used for upgrading of the
biocrude, the minimum fuel selling price can be reduced by approximately
7%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.