Advanced air revitalization system testing

A previously developed experimental air revitalization system was tested cyclically and parametrically. One-button startup without manual interventions; extension by 1350 hours of tests with the system; capability for varying process air carbon dioxide partial pressure and humidity and coolant source for simulation of realistic space vehicle interfaces; dynamic system performance response on the interaction of the electrochemical depolarized carbon dioxide concentrator, the Sabatier carbon dioxide reduction subsystem, and the static feed water electrolysis oxygen generation subsystem, the carbon dioxide concentrator module with unitized core technology for the liquid cooled cell; and a preliminary design for a regenerative air revitalization system for the space station are discussed

Rare isotope studies involving catalytic oxidation of CO over platinum-tin oxide

Results of studies utilizing normal and rare oxygen isotopes in the catalytic oxidation of carbon monoxide over a platinum-tin oxide catalyst substrate are presented. Chemisorption of labeled carbon monoxide on the catalyst followed by thermal desorption yielded a carbon dioxide product with an oxygen-18 composition consistent with the formation of a carbonate-like intermediate in the chemisorption process. The efficacy of a method developed for the oxygen-18 labeling of the platinum-tin oxide catalyst surface for use in closed cycle pulsed care isotope carbon dioxide lasers is demonstrated for the equivalent of 10 to the 6th power pulses at 10 pulses per second

Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process

Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata. In the second stage, the liquid end-products of the MES process are converted to the final product by a second microorganism, Acinetobacter baylyi in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon-neutral chemicals or biofuels.acceptedVersionPeer reviewe

Carbon dioxide concentration in Mediterranean greenhouses : how much lost production?

In the absence of artificial supply of carbon dioxide in the greenhouse environment, the CO2 absorbed in the process of photosynthesis must ultimately come from the external ambient through the ventilation openings. This requires that the CO2 concentration within the house must be lower than the external concentration, as there would be no flow inwards otherwise. Since potential assimilation (that is, the assimilation level that can be attained when no other factor is limiting) is heavily dependent on carbon dioxide concentration, this implies that assimilation is reduced, whatever the light level or crop status. The ventilation of the greenhouse implies a trade-off between ensuring inflow of carbon dioxide and maintaining an adequate temperature within the house, particularly during sunny, chilly days. We apply a simple model, on which the Dutch ¿philosophy¿ of CO2 fertilisation is based, for estimating the potential production loss, through data measured in commercial greenhouses in Almeria and Sicily. Thereafter we discuss the management options for a grower to limit losses. In particular we analyse costs, potential benefits and consequences of bringing in more carbon dioxide either through increased ventilation, at the cost of lowering temperature, or through artificial supply. We find out that, whereas the reduction in production caused by depletion is comparable to the reduction resulting from the lower temperature caused by ventilation to avoid depletion, compensating the effect of depletion is much cheaper than making up the loss by heating

Unintentional Climate Policy: Swedish experiences of carbon dioxide emissions and economic growth 1950-2005

This paper examines the development of carbon dioxide emissions in Sweden, especiallyn with a focus on the absolute reductions during the post-war period, during the 1970s and 1980s. The paper shows that the largest reductions were achieved before the introduction of an active climate policy in 1991. This was in turn the result of significant improvements in energy efficiency and energy conversion, while structural changes were considerably less important. One reason behind this decoupling process may be that the active energy policy put pressure on households and industries to conserve energy and to substitute from oil to electricity and biofuels. The process was substantially reinforced by the development of world oil prices in combination with the development of domestic electricity prices, where nuclear power seems to have played an important role.Sweden; climate policy; economic growth; carbon dioxide reduction; carbon tax

Reducing Decomposition Time in Landfills by an Aerobic Process

This experiment was performed to determine if sludge produced by the paper industry could be composted faster by promoting the aerobic degradation process. To perform this experiment, I chose a sludge produced by a virgin pulp mill. Once I collected sludge, it was dewatered to a moisture content of sixty-five percent or less. As soon as the sludge was dewatered, I set up four separate composting systems, three of which were run under aerobic conditions and one that was run under anaerobic conditions. The anaerobic conditions only had sludge and plastic for its bulking agent. In the aerobic systems there were three different types of bulking agents used; pine bark, plastic and compost. In the aerobic systems air was introduced into the system. To determine how fast each of the processes was composting, I collected the gases that were produced by each of the systems. The gases that are produced by an anaerobic process was carbon dioxide and methane, whereas an aerobic process produces carbon dioxide and water. Therefore, by analyzing the gases produced by each of the systems periodically and determining the amount of carbon dioxide produced by each of the systems, one can determine the rate of decomposition of the sludge for each of the separate systems. Also the chemical oxygen demand (COD) was determined for each of the system, before and after the degradation occurred. COD was used to measure that content of organic matter in the sludge. This also helped in determining the degradation that has occurred in each of the systems

Optimization of unit commitment considering carbon gas emission reduction utilizing firefly algorithm

The necessity for electrical energy has been currently significant to support economic growth in Indonesia, expected to annually increase every year. The increasing demand for electricity denotes that the electrical energy supplied by the generator is relatively large. In general, electricity generation in Indonesia utilizes fossil fuels in the generation process thus it creates emissions in the form of carbon dioxide (CO2), which are released into the air in large quantities. Therefore, planning is deemed instrumental, thereby encouraging that generation scheduling at an economical cost is required in the generation of each unit in order to adjust the load that changes every time. This final project discusses the problem of unit commitment (UC) with the addition of a carbon capture and storage (CCS) system in the generator. The Carbon Capture and Storage (CCS) process refers to a technology capturing up to 85% of carbon dioxide (CO2) emission as, the result of utilizing fossil fuels in electricity generation and industrial processes to prevent carbon dioxide from entering the atmosphere. The optimization algorithm utilized in this final project is the Firefly Algorithm (FA). The objective function that will be optimized lies in the cost of generation, scheduling on and off for each generator and carbon dioxide (CO2) emissions. The data used in this optimization includes the IEEE of 30 bus system and the addition of Carbon Capture and Storage Plants. The test results indicate that the FA method is able to perform UC calculations considering Carbon Capture and Storage

Carbon dioxide flash-freezing applied to ice cream production

Includes bibliographical references (p. 62-64).Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.(cont.) Carbon dioxide is recompressed from 1.97 x 106 Pa (285 psi) to 3.96 x 106 Pa (575 psi). The process is scaled by increasing the number of nozzles to accommodate the desired flow rate. Only 165 nozzles are required to flash freeze the ice cream mix at a 2000 L/hr ice cream production rate. The power consumption of a continuous cycle implementation is modeled including single or double stage carbon dioxide recovery and compression, pre-cooling of the carbon dioxide by a standard condensing unit, pumping of the ice cream mix at high pressure and extrusion of the ice cream powder by a piston or screw extruder. The power consumption of an implementation recovering 95% of the carbon dioxide is approximately 37.3% of the power consumption of a conventional process. The cost of the make-up carbon dioxide is $0.002 per liter of ice cream. A cart implementation is also possible.Ice cream mix and other liquids are frozen by direct contact with carbon dioxide while carbon dioxide is throttled from a liquid phase to a saturated vapor phase. The process is demonstrated with a proof-of-principle apparatus that freezes discrete batches of mix. The fluid consumption, power consumption and space requirement of a continuous cycle implementation are modeled. In the proof-of-principle apparatus and the continuous cycle model, the ice cream mix is sprayed into the liquid carbon dioxide using 1.0 GPH Delavan fuel nozzles; the combined fluid is throttled by 2.0 GPH Delavan fuel nozzles, forming a fine mist during flash-freezing. The pressure at the outlet of the throttle determines the temperature of the saturated carbon dioxide vapor after the flashing process. The resulting product is a frozen carbonated ice cream powder. Depending on the implementation, 50-99% of the carbon dioxide flow is vented and can be compressed and recycled with additional make-up carbon dioxide flow. The required ratio of carbon dioxide to ice cream mix is found by balancing the change in enthalpy of each liquid from the inlet to the outlet state. For ice cream mix frozen from 5°C to -200C, the ratio is shown to be about 1.1.by Teresa Susan Baker.S.M