Energy balances,greenhouse gas emissions and economics of biochar production from palm oil empty fruit bunches

This paper presents results from a gate-to-gate analysis of the energy balance, greenhouse gas (GHG) emissions and economic efficiency of biochar production from palm oil empty fruit bunches (EFB). The analysis is based on data obtained from EFB combustion in a slow pyrolysis plant in Selangor, Malaysia. The outputs of the slow pyrolysis plant are biochar, syngas, bio-oil and water vapor. The net energy yield of the biochar produced in the Selangor plant is 11.47 MJ kg⁻¹ EFB. The energy content of the biochar produced is higher than the energy required for producing the biochar, i.e. the energy balance of biochar production is positive. The combustion of EFB using diesel fuel has the largest energy demand of 2.31 MJ kg⁻¹ EFB in the pyrolysis process. Comparatively smaller amounts of energy are required as electricity (0.39 MJ kg⁻¹ EFB) and for transportation of biochar to the warehouse and the field (0.13 MJ kg⁻¹ EFB). The net greenhouse gas emissions of the studied biochar production account for 0.046 kg CO₂-equiv. kg⁻¹ EFB yr⁻¹ without considering fertilizer substitution effects and carbon accumulation from biochar in the soil. The studied biochar production is profitable where biochar can be sold for at least 533 US-$ t⁻¹. Potential measures for improvement are discussed, including higher productivity of biochar production, reduced energy consumption and efficient use of the byproducts from the slow pyrolysis.     

Experimental investigations on regeneration energy and energy management strategy in series hydraulic/electric synergy system

This research work draws an insight into the experimental investigations on a series hydraulic/electric synergy system—a green transportation system. An experimental test rig of the system with all necessary sensors and instrumentation has been developed to study the energy saving through hydraulic regenerative braking. The effect of various system parameters, such as braking time, maximum accumulator pressure, pre-charge pressure of hydro-pneumatic accumulator, volumetric displacement of the hydraulic master pump, and hydraulic regeneration pump on the quantum of regeneration energy, was analyzed. In addition, an AMESim model of the real-time experimental test rig has been developed and validated with experimental results. A set of five different experimental designs (parameter variations) of the system is defined with the available standard component sizes. The best design is selected of the available experimental designs based on the maximum hydraulic regeneration energy and regeneration efficiency. It was observed that the selected design has an energy efficiency of 13.3% and a regeneration efficiency of 43.8%. An accumulator-centric control strategy for energy management is developed and implemented on the experimental test rig configured with the selected design. The effectiveness of the control strategy is tested through experiments and simulation on the developed test rig.     

Green energy generation by pressure retarded osmosis: State of the art and technical advancement—review

Pressure-retarded osmosis (PRO) is a method for converting salinity gradients to power by allowing water to flow through a semi-permeable membrane against an applied hydraulic pressure. PRO already has a long history, starting from the middle of the last century, and has rapidly improved in recent years. In this paper, we present a historical development of PRO since its inception: the development of this renewable energy process has gone through several stages, depending on technological developments, worldwide energy demands, and environmental concerns. The technological progress of the process is also studied, as well as its cost viability and environmental impact. Finally, some ideas to further develop the PRO process and mitigate its detrimental effects are discussed.     

人类自我科学管理是实现可持续发展的必然选择

现今人口规模的不断膨胀和物质生活水平的日益提高,对资源和环境造成的压力急剧增加。分析了世界现状和可持续发展面临的挑战之后,提出人类要实现可持续发展必须要进行自我科学管理,分别从人类自我定位、对待科技的态度、人口管理、人类消费管理4个方面进行讨论和阐述。人类首先需重新审视自己,进行自我定位;其次要正确对待科技;控制人口数量和转变不合理消费是目前人类自我管理的重要任务,对此提出一些实施对策。     

On the confluence of city living,energy saving behaviours and direct residential energy consumption

The purpose of this study is to shed light on the connection between income, dwelling type, tenure type and city living, in terms of both a household’s energy saving behaviours and direct residential energy consumption. This study employs data from the Household Energy Consumption Survey, Australia. Using a seemingly unrelated regression (SUR) system of equations the results reveal some key mechanisms which may allow householders to realise lower levels of energy consumption and hence lower carbon emissions. The results indicate that there are characteristics unique to living in a city that are linked to higher levels of direct residential energy consumption. On a number of measures (e.g. household income, tenure type and dwelling type), the results point to a lower likelihood of engaging in energy saving behaviours in cities. Also, depending on the number of energy saving behaviours, these actions have the potential to more than offset higher direct residential energy consumption of householders residing in separate houses. Coupled with these findings renters, a more vulnerable social group, are found to be significantly disadvantaged, suffering from a much lower adaptive capacity. Specifically, householders who rent their home are 77% less likely to have solar electricity. A result which may reflect differences in access to opportunity. Further, householders who rent are less likely to engage in energy saving actions. A finding which may reflect difference in ontological security and the greater psychological burden associated with undertaking energy saving behaviours (a barrier) borne by renters not shared with home owners.     

Vitalizing effects of being outdoors and in nature

Five studies utilizing survey, experimental, and diary methods assessed the effects of being outdoors on subjective vitality. In Study 1, we used a vignette method to examine whether being outdoors was associated with vitality, above and beyond the influences of physical activity and social interactions. Study 2 explored the effects of being outdoors on vitality through an experimental design contrasting indoor and outdoor walks. In Study 3, participants were exposed to photographic scenes of either nature or buildings. Results showed that only the nature scenes enhanced subjective vitality. Studies 4 and 5 used a diary methodology to examine within-person variations in subjective energy as a function of being outdoors, again controlling for physical and social activity. Being outdoors was associated with greater vitality, a relation that was mediated by the presence of natural elements. Limitations of these studies are discussed, as well as their implications for research on energy and vitalization.     

谈环境监察对节能减排的促进作用

环境监察是直接而具体的环境保护行为,是国家环保部门进行监督、强性执法的方式,是对环境进行有效监督的方法。环境监察需要执法部门现场进行监督与处理。具有直接性、强制性。大多分为事前、事中与事后监察。环境监察范围主要是对乱排放污染物,对生态造成破坏的单位或个人及时进行检查、处理。有些情况下,需要进行强制性执法。     

Simultaneous photocatalytic treatment of Cr(VI), Ni(II) and SDBS in aqueous solutions: Evaluation of removal efficiency and energy consumption

Simultaneous photocatalytic reduction of poisonous Cr(VI) and Ni(II) ions, coupled with photocatalytic oxidation of sodium dodecyl benzene sulfonate (SDBS) were studied with a trace amount of commercial titania nanoparticles and by means of a direct-photo-irradiation reactor. The co-presence of metal ions and SDBS causes metal ions reduction as well as SDBS oxidation to enhance and energy efficiency to improve. XRD, XPS and FTIR analysis were used to characterize TiO₂ particles before and after usage with the aim of evaluating the mechanism of reactions. The effect of major operating parameters, pH and temperature, was investigated. Under conditions of [Cr(VI)]₀ = [Ni(II)]₀ = 5 mg/L, [SDBS]₀ = 10 mg/L, [TiO₂] = 40 mg/L, pH 6 and T = 35 °C; the removal efficiencies of 55.4%, 71.2% and 57.2% were obtained, respectively, for Cr(VI) and Ni(II) reduction, as well as for SDBS oxidation, after 110 min operation. The relevant kinetic model jointed with the Arrhenius equation was introduced. Pseudo-first-order reactions are relevant. Energy consumption (electrical and thermal) evaluations revealed that operations at higher temperatures provide significant cost reduction. Meantime, a criterion was proposed for a consistent assessment of this kind of processes.     

Is the reproduction of Donax trunculus affected by their sites of origin contrasted by their level of contamination?

The reproductive cycle of bivalves is regulated by several natural environmental factors but exposure to chemical pollutants can also interfere and may result in advanced or delayed spawning season. To our knowledge, the gametogenic cycle of the suspension-feeder bivalve Donax trunculus has not yet been used as biomonitoring tool in ecotoxicological surveys. The aim of this study was to examine over a year physiological reproductive endpoints (sex-ratio, gametogenic and energy reserve cycles) and biological indices (condition index, allometry) in D. trunculus originating from two sites differing by their level of contamination. Specimens were collected bimonthly from November 2008 to October 2009 from a polluted site (Radès Méliane) and a comparatively reference site (Sidi Jehmi) in the Gulf of Tunis (Tunisia). Five stages were depicted by histological examination of gonads: undifferentiated, developing, mature, spawn and spent. Differences in the gametogenic cycle according to the site of origin of bivalves were observed. The spawning period began in March and was maximum in May in bivalves from both sites, but the percentage of spawning animals was higher in the polluted site vs the reference site. The spawning period was shorter in animals from the polluted site comparatively to the reference site. Energy reserves (glycogen, lipids) were higher in March and May comparatively to the other studied periods in bivalves from both sites. Lower energy reserves levels were usually observed in animals from the polluted site compared to the reference site. Seasonal variations of the condition index were associated to the reproductive and nutritive status of bivalves. Differences in allometry were depicted between bivalves from both studied sites. If we try to link allometry, energy reserves and reproduction, it can be hypothesized that for bivalves from the reference site, energy reserves are allocated to gametogenesis and length growth. For bivalves from the polluted site, energy reserves could be devoted to tolerance to chemical stress and to reproductive processes. Therefore, D. trunculus appears as a suitable sentinel species for the assessment of the ecotoxicological risk of contaminants such as endocrine disruptors.     

Body metal concentrations and glycogen reserves in earthworms (Dendrobaena octaedra) from contaminated and uncontaminated forest soil

Stress originating from toxicants such as heavy metals can induce compensatory changes in the energy metabolism of organisms due to increased energy expenses associated with detoxification and excretion processes. These energy expenses may be reflected in the available energy reserves such as glycogen. In a field study the earthworm, Dendrobaena octaedra, was collected from polluted areas, and from unpolluted reference areas. If present in the environment, cadmium, lead and copper accumulated to high concentrations in D. octaedra. In contrast, other toxic metals such as aluminium, nickel and zinc appeared to be regulated and kept at low internal concentrations compared to soil concentrations. Lead, cadmium and copper accumulation did not correlate with glycogen reserves of individual worms. In contrast, aluminium, nickel and zinc were negatively correlated with glycogen reserves. These results suggest that coping with different metals in earthworms is associated with differential energy demands depending on the associated detoxification strategy.