Biofuels from pyrolysis in perspective: trade-offs between energy yields and soil-carbon additions.
نویسندگان
چکیده
Coproduction of biofuels with biochar (the carbon-rich solid formed during biomass pyrolysis) can provide carbon-negative bioenergy if the biochar is sequestered in soil, where it can improve fertility and thus simultaneously address issues of food security, soil degradation, energy production, and climate change. However, increasing biochar production entails a reduction in bioenergy obtainable per unit biomass feedstock. Quantification of this trade-off for specific biochar-biofuel pathways has been hampered by lack of an accurate-yet-simple model for predicting yields, product compositions, and energy balances from biomass slow pyrolysis. An empirical model of biomass slow pyrolysis was developed and applied to several pathways for biochar coproduction with gaseous and liquid biofuels. Here, we show that biochar production reduces liquid biofuel yield by at least 21 GJ Mg(-1) C (biofuel energy sacrificed per unit mass of biochar C), with methanol synthesis giving this lowest energy penalty. For gaseous-biofuel production, the minimum energy penalty for biochar production is 33 GJ Mg(-1) C. These substitution rates correspond to a wide range of Pareto-optimal system configurations, implying considerable latitude to choose pyrolysis conditions to optimize for desired biochar properties or to modulate energy versus biochar yields in response to fluctuating price differentials for the two commodities.
منابع مشابه
Ethical Perspective: Five Unacceptable Trade-offs on the Path to Universal Health Coverage
This article discusses what ethicists have called “unacceptable trade-offs” in health policy choices related to universal health coverage (UHC). Since the fiscal space is constrained, trade-offs need to be made. But some trade-offs are unacceptable on the path to universal coverage. Unacceptable choices include, among other examples from low-income countries, to expand coverage for services wit...
متن کاملDefining Pathways and Trade-offs Toward Universal Health Coverage; Comment on “Ethical Perspective: Five Unacceptable Trade-offs on the Path to Universal Health Coverage”
The World Health Organization’s (WHO’s) World Health Report 2010, “Health systems financing, the path to universal coverage,” promoted universal health coverage (UHC) as an aspirational objective for country health systems. Yet, in addition to the dimensions of services and coverage, distribution of coverage in the population, and financial risk protection highlighted by the report, the conside...
متن کاملUniversal Health Coverage – The Critical Importance of Global Solidarity and Good Governance; Comment on “Ethical Perspective: Five Unacceptable Trade-offs on the Path to Universal Health Coverage”
This article provides a commentary to Ole Norheim’ s editorial entitled “Ethical perspective: Five unacceptable trade-offs on the path to universal health coverage.” It reinforces its message that an inclusive, participatory process is essential for ethical decision-making and underlines the crucial importance of good governance in setting fair priorities in healthcare. Solidarity on both natio...
متن کاملCarbon-negative biofuels from low-input high-diversity grassland biomass.
Biofuels derived from low-input high-diversity (LIHD) mixtures of native grassland perennials can provide more usable energy, greater greenhouse gas reductions, and less agrichemical pollution per hectare than can corn grain ethanol or soybean biodiesel. High-diversity grasslands had increasingly higher bioenergy yields that were 238% greater than monoculture yields after a decade. LIHD biofuel...
متن کاملRenewable fuels from pyrolysis of Dunaliella tertiolecta: An alternative approach to biochemical conversions of microalgae
The cultivation of microalgae as a feedstock for renewable fuels is widely touted as a way to sequester CO2 while negating food versus fuel competition for land. However, the widespread industrial use of microalgae for biofuels has yet to reach a critical stage based on lipid extraction alone. One alternative to the transesterification of microalgae for liquid fuel production is to use thermoch...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Environmental science & technology
دوره 48 11 شماره
صفحات -
تاریخ انتشار 2014