Recently Japanese government's energy policy calls for an expanded use of natural gas in order to reduce the emission of greenhouse gases. Especially, natural gas hydrates, which are solid materials that resemble ice, are expected to become one of new type natural gas resources, and several applications such as natural gas storage and cold thermal energy storage have been applied in various industrial applications. Typical, cement industry consumes a huge amount of heat and energy, and much of carbon dioxide (CO2) emission occurs not only from fossil fuel combustion but also from the calcinations of limestone, which is the main material. Therefore the authors have put forward a scheme which makes possible the CO2 separation and energy saving by using hydrate technology for cement manufacturing process, and then evaluated the validity of the scheme by calculating the energy balance. Consequently, by cooling the introductory air of a cement grinding process by hydrate cold energy, the grinding efficiency has improved about 1% and 0.4kWh/t-cl reduction of the power consumption was achieved. By cold-water use to condenser of a tower waste heat boiler, the power generation output increased from 21.9kWht/t-cl with 22.5 kWt/t-cl, and boiler efficiency has been improved by 1.6%. By proposing CO2 separating by the hybrid system with using the chemistry absorbing method together, the energy 234kWh/t-cl and 53% of a simple hydrate system. CO2 was reduced from 782kg/t-cl to 492kg/t-cl. In addition, the proposed system was validated based on these trial calculation results.
In Japan, a lot of man-made forest is not appropriately managed. Considering problems of them and international tendencies, we need to manage forest suitably to regional ecosystems and forestry from now on. This study implicates political measures for it particularly focusing on Japanese private forest, referencing to the forest policy and nature near forestry of Baden-Württemberg in Germany. In conclusion, it is generally necessary to strengthen participations of the administrative authority in private forest maintenance, improve the density of road network in forest and achieve the real decentralization in the field of forest policy, taking care international tendencies. In the forest particularly aimed at fulfilling the multifunction of forest it is necessary to introduce nature near forestry. We should politically support and promote research and development.
With rising prices for imported fossil fuel and growing concerns about global warming, the developing countries of Sub-Saharan Africa may no longer be able to depend upon fossil diesel as a reliable source of energy in the future. Fortunately, the availability of local resources such as ethanol (EtOH), bio-oils, and hydrated lime makes it feasible to introduce renewable sources of power such as biodiesel via ethanolysis. A previous paper from our group reported concentration changes of triglycerides (TG), diglycerides (DG), monoglycerides (MG), and the added glycerol (GL) in the pretreatment with glycerol, and identified the glycerolysis of TG as the mechanism behind the reaction rate enhancement of the following transesterification. It will also be important, for actual application to biodiesel production, to determine the reaction rates and equilibrium constants. In the present study we determined the thermal pretreatment kinetics of a groundnut (Arachis hypogaea) oil feedstock premixed with glycerol and calcium hydroxide (Ca(OH)2) at 100 °C over reaction times from 1 to 3 h, while measuring the concentration changes of TG, DG, MG, and GL over time to determine the rate constants. Next, we used the data obtained to calculate the equilibrium constants. Through this approach, we successfully determined the reaction rate of the catalytic TG glycerolysis, the process that yielded DG and MG as reactive intermediates for the ethanolysis reaction. A GL/TG molar ratio of 2.35 is recommended for optimal performance of TG glycerolysis.
In this paper, we present a theoretical framework on positive and negative environmental implications of biofuels and underpin this discussion with an empirical analysis for the European Union 27 (EU) and the United States of America (US). Based on the framework and by means of time series analysis, we estimate CO2 reductions as a positive result of biofuels consumption and the fertilization increase as a negative effect of biofuels production in the EU and US in 2006-2018. Furthermore, we point out a number of questions to be addressed with regard to environmental issues in the biofuels policy in the future.
Outdoor field storage of round-baled rice straw to suppress the cost of producing bio-ethanol from rice straw was investigated. Harvested rice straw was dried, collected, compressed and packed into round bales (rolls) by a round baler. Usually, the rolls are stored in a warehouse, or outdoors wrapped in a film coat. However, these storage costs push up the price of the bio-ethanol produced and reduce energy efficiency. To avoid this, outdoor field storage of rice straw rolls with or without film wrapping (wrapped rolls or non-wrapped rolls) was investigated in this study. The rolls were stored for about 9 months, from 19 December 2008 to 9 September 2009, taking into consideration the supply of rice straw for demonstrating a bio-ethanol pilot plant throughout the year. No significant increase of temperature in each roll was observed during the storage term, even though an increase was reported in previous studies. However, the straw should be stocked for other seasons, and it is important to grasp any problems during the storage period. In this study, no significant change was observed in the non-wrapped rolls throughout the term, suggesting that non-film wrapping round-baled rice straw can be stored in fields outdoors.