1,119 research outputs found

    Location or insolation: the importance of siting in emissions mitigation from solar photovoltaics

    Full text link
    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138324/1/wene249.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138324/2/wene249_am.pd

    Biotechnological aspects of sulfate reduction with methane as electron donor

    Get PDF
    Biological sulfate reduction can be used for the removal and recovery of oxidized sulfur compounds and metals from waste streams. However, the costs of conventional electron donors, like hydrogen and ethanol, limit the application possibilities. Methane from natural gas or biogas would be a more attractive electron donor. Sulfate reduction with methane as electron donor prevails in marine sediments. Recently, several authors succeeded in cultivating the responsible microorganisms in vitro. In addition, the process has been studied in bioreactors. These studies have opened up the possibility to use methane as electron donor for sulfate reduction in wastewater and gas treatment. However, the obtained growth rates of the responsible microorganisms are extremely low, which would be a major limitation for applications. Therefore, further research should focus on novel cultivation technique

    Book of abstracts – Process metallurgy - Section B

    Get PDF

    Resident research associateships. Postdoctoral and senior research awards: Opportunities for research at the Jet Propulsion Laboratory

    Get PDF
    Opportunities for research as part of NASA-sponsored programs at the JPL cover: Earth and space sciences; systems; telecommunications science and engineering; control and energy conversion; applied mechanics; information systems; and observational systems. General information on applying for an award for tenure as a guest investigator, conditions, of the award, and details of the application procedure are provided

    XVIII International Coal Preparation Congress

    Get PDF
    Changes in economic and market conditions of mineral raw materials in recent years have greatly increased demands on the ef fi ciency of mining production. This is certainly true of the coal industry. World coal consumption is growing faster than other types of fuel and in the past year it exceeded 7.6 billion tons. Coal extraction and processing technology are continuously evolving, becoming more economical and environmentally friendly. “ Clean coal ” technology is becoming increasingly popular. Coal chemistry, production of new materials and pharmacology are now added to the traditional use areas — power industry and metallurgy. The leading role in the development of new areas of coal use belongs to preparation technology and advanced coal processing. Hi-tech modern technology and the increasing interna- tional demand for its effectiveness and ef fi ciency put completely new goals for the University. Our main task is to develop a new generation of workforce capacity and research in line with global trends in the development of science and technology to address critical industry issues. Today Russia, like the rest of the world faces rapid and profound changes affecting all spheres of life. The de fi ning feature of modern era has been a rapid development of high technology, intellectual capital being its main asset and resource. The dynamics of scienti fi c and technological development requires acti- vation of University research activities. The University must be a generator of ideas to meet the needs of the economy and national development. Due to the high intellectual potential, University expert mission becomes more and more called for and is capable of providing professional assessment and building science-based predictions in various fi elds. Coal industry, as well as the whole fuel and energy sector of the global economy is growing fast. Global multinational energy companies are less likely to be under state in fl uence and will soon become the main mechanism for the rapid spread of technologies based on new knowledge. Mineral resources will have an even greater impact on the stability of the economies of many countries. Current progress in the technology of coal-based gas synthesis is not just a change in the traditional energy markets, but the emergence of new products of direct consumption, obtained from coal, such as synthetic fuels, chemicals and agrochemical products. All this requires a revision of the value of coal in the modern world economy

    Flow characteristics study of fly ash slurry in hydraulic pipelines using computational fluid dynamics

    Get PDF
    Transportation of fly ash slurry via pipelines has been recognized as a potential economical and dependable mode of solid transportation. It also bids various other advantages over the conventional means of transportation. For improved understanding of the flow characteristics of these pipelines, investigators throughout the world have been analyzing the flow experimentally numerically and theoretically. Slurry pipeline systems are regularly used crosswise the world for the transportation of fly ash from the power plant to the ash ponds. These pipeline are very much energy exhaustive and also leads to disproportionate and inordinate wear of pipelines and wastage of water. Objective of the present work is to conduct a methodical and logical study of fly ash slurry transportation in a pipeline at higher concentrations by the use of computational fluid dynamics and study the flow characteristics and pressure drops. An effort has been made in this study to develop comprehensive slurry flow model using CFD and utilize the model to predict pressure drop and validating the results with the calculated results. A broad computational fluid dynamics (CFD) model was established in the current study to gain understanding into the solid liquid slurry flow in pipelines. The approach adopted in here is studying and solving the problem by mathematical modeling method. In this work, the solid suspension in a fully developed pipe flow was simulated and analyzed A 20m pipe with a diameter of 0.5m is modeled, through which flow is conducted where modelling and meshing is done using ANSYS Fluent. High viscosity fly ash slurry with five different concentrations, 50%, 60%, 65%, 68% and 70% by weight of fly ash is passed and for each concentration five different velocities like 3, 3.5, 4, 4.5 and 5 m/s are used and pressure drops are calculated. Other characteristics studied are volume fraction, eddy viscosity and turbulence kinetic energy

    Evaluation of Equalization Basins as Initial Treatment for Flue Gas Desulfurization Waters

    Get PDF
    Coal-fired power plants are introducing flue gas desulfurization (FGD) scrubbers to reduce sulfur dioxide and mercury emissions in order to meet air quality standards. FGD scrubber systems utilize a mixture of limestone, water, and organic acids to precipitate sulfur compounds. The resulting FGD water and associated particulates often contain constituents of concern including chlorides, inorganic elements (Hg, As, and Se), and sulfates that must be treated before discharge. Constructed wetland treatment systems, consisting of an equalization basin followed by wetland reactors, present a viable option to efficiently treat FGD waters. Equalization basins are designed to cool and homogenize FGD water and settle particulates. Specific research objectives focused on equalization basins are: 1) to characterize FGD particulates in terms of elemental and mineralogical composition; 2) to determine size and settling rates of FGD particulates; 3) to determine if Hg, As, and Se concentrations within FGD water stored in an equalization basin change with time; and 4) to determine if toxicity of FGD water within an equalization basin changes during a 24 hr hydraulic retention time. The most common FGD particle type was characterized as gypsum. Other particle types identified included fly ash and iron oxides. FGD particulates settled in an equalization basin are interpreted to have originated during coal combustion and FGD processes. The majority of FGD particulates were determined to be silt size, and settling analysis shows that 95% of these particulates settled to the bottom of a typical 2.5 m deep equalization basin within approximately 4 hrs. FGD particulates contained concentrations of Hg, As, and Se, and as particulates settled, constituents were removed from the water column. Analysis of FGD water samples indicate that aqueous concentrations of Hg and Se decreased in the pilot-scale equalization basins by 20 µg/L and 200 µg/L, respectively, during a 24 hr hydraulic retention time. Data from toxicity tests indicate that equalization basins do not decrease toxicity of FGD water to aquatic organisms. Equalization basins are necessary for initial treatment of FGD water by settling particulates, which may contain Hg, As, and Se. Additional treatment for these waters occurs in the wetland reactors

    Financing coal-fired power plant to demonstrate CCS (carbon capture and storage) through an innovative policy incentive in China

    Get PDF
    Traditional policy incentives for carbon capture and storage (CCS) mainly rely on fiscal subsidies, which tend to put an inordinate strain on public finances. This study attempts to explore a non-fiscal incentive policy, granting a time extension (extra electricity quota), to finance early CCS demonstration projects in China. We find that coal-fired power plant (CFPP) operate at a loss even without CCS retrofitting under the current electricity quota (4000 h per year), while it can make profits with CCS retrofitting if extra electricity quotas are provided. Specifically, the electricity quota needs to be roughly 4709–7260 h per year with the CO2 capture level ranging from 0.1 to 1 Mt per year in the demonstration stage. In particular, the levelized cost of electricity (LCOE) of CFPP with a capture level of 1 Mt per year is estimated at 298.8 CNY/MWh if the electricity quota reaches 7000 h per year, which is approximately equal to that of CFPP without CCS retrofitting and extra electricity quota (292.2 CNY/MWh). Thus, the extra electricity quota can be considered as an economically feasible policy incentive, and related results are able to provide useful information for electric power enterprises and government decision-makers

    Hydrogen sulfide removal from synthetic biogas using anoxic biofilm reactors

    Get PDF
    Tämän tutkimuksen tarkoituksena oli kehittää bioreaktoreita sulfidin poistamiseen nestemäisistä jätevirroista anoksisissa olosuhteissa. Lisäksi tavoitteena oli mahdollistaa rikkivetyä sisältävien kaasumaisten ja nitraattia sisältävien nestemäisten jätevirtojen yhtaikainen käsittely. Ensiksi tutkittiin liukoisten epäorgaanisten rikkiyhdisteiden hapetusta rikkiä hapettavia ja nitraattia pelkistäviä (SO-NR) bakteereita sisältävällä mikrobiviljelmällä kahdessa erilaisessa bioreaktorissa, leijupetireaktorissa (FBR) ja kantajakappalereaktorissa (MBBR). Bioreaktoreiden toimintaa syötteen eri typen ja rikin moolisuhteilla vertailtiin käyttäen tiosulfaattia elektronidonorina ja nitraattia elektroniakseptorina. Molemmissa reaktoreissa saavutettiin yli 98 %:n tiosulfaatin poistotehokkuus ja nitraatti saatiin poistettua kokonaan N/S-suhteen ollessa 0,5. Erittäin typpirajoitteisissa olosuhteissa (NS suhde 0,1), MBBR:llä saavutettu tiosulfaatin poistotehokkuus (37,8 %) oli korkeampi kuin FBR:llä saavutettu tiosulfaatin poistotehokkuus (26,1 %). Kun syötteen N/S suhde palautettiin arvoon 0,5, MBBR:llä tiosulfaatin poistotehokkuus palautui yhden päivän aikana arvoon 94 %, kun taas FBR:llä kesti kolme päivää, että tiosulfaatin poistotehokkuus nousi arvoon 80 %. Kummallekin reaktorille kehitettiin oman euroverkko-pohjainen malli, joka ennusti luotettavasti tiosulfaatin ja nitraatin poistotehokkuuksia eri olosuhteissa. MBBR:ään rikastunutta SO-NR-viljelmää hyödynnettiin valutusbiosuodattimessa (BTF) rikkivetyä ja nitraattia sisältävien synteettisten jätevirtojen samanaikaiseen käsittelyyn. Anoksisella BTF:llä suurin saavutettu rikkivedyn poistokapasiteetti oli 19,2 g S m-3 h-1 (99 % poistotehokkuus) rikkivetykuorman ollessa 20,0 g S m-3 h-1 (~500 ppmv) ja N/S suhteen noin 1,7. Koska nitraattia sisältävät jätevedet voivat sisältää myös orgaanisia yhdisteitä toisessa BTF:ssä tutkittiin Paracoccus versutus MAL 1HM19 kannan kykyä poistaa samanaikaisesti rikkivetyä, nitraattia ja orgaanisia yhdisteitä. Tällä BTF:llä saavutettiin nitraatin poistonopeus 16,7 g NO3--N m-3 h-1 ja asetaatin poistonopeus 42,0 g-asetaattia m-3 h-1. Saavutetut poistonopeudet olivat korkeampia kuin autotrofisia SO-NR bakteereja hyödyntävällä BTF:llä saavutetut arvot, jotka olivat 11,1 g NO3--N m-3 h-1 ja 10,2 g-asetaattia m-3 h-1. SO-NR bakteerien hallitseman anoksisen BTF:n toimintaa tutkittiin vaihtuvissa olosuhteissa kuten muuttuva kaasun ja valutusnesteen virtausnopeus, katkonainen nitraatin syöttö ja rikkivedyn shokkikuormitus, sillä tällaiset häiriöt ovat mahdollisia käytännön sovelluksissa. Olosuhteiden ohimenevät muutokset vaikuttivat merkittävästi rikkivedyn poistokapasiteettiin. Esimerkiksi rikkivedyn shokkikuormituksen jälkeen kesti 1,7 päivää ennen kuin rikkivedyn poistotehokkuus palasi yli 99 %:n tasolle. Yhteenvetona voidaan todeta, että MBBR mahdollisti tehokkaamman tiosulfaatin poiston kuin FBR erityisesti typpirajoitteisissa olosuhteissa. MBBR:n ja BTF:n osoitettiin palautuvan nopeasti ohimenevistä kuormitustilanteista ja mahdollistavan siis vakaan epäorgaanisten rikkiyhteisen poiston synteettisistä jätevirroista.The aim of this work was to develop and study anoxic bioreactors for the removal of reduced inorganic sulfur compounds from liquid and gaseous waste streams. In addition, the aim was to enable process integration for the simultaneous treatment of H2S con-taminated gas streams and NO3--containing wastewater. The experiments related to sulfide oxidation in the liquid phase were conducted in two different attached growth bioreactors, i.e. a fluidized-bed reactor (FBR) and a moving bed biofilm reactor (MBBR), inoculated with the same mixed culture of sulfur-oxidizing nitrate-reducing (SO-NR) bacteria. The bioreactors were operated under different nitro-gen-to-sulfur (N/S) molar ratios using S2O32- and NO3- as an energy source and electron acceptor, respectively. Results revealed that both the FBR and MBBR achieved S2O32- removal efficiencies (RE) >98% and completely removed NO3- at an N/S ratio of 0.5. Under severe nitrate limitation (N/S ratio of 0.1), the S2O32- RE in the MBBR (37.8%) was higher than that observed in the FBR (26.1%). In addition, the MBBR showed better resilience to nitrate limitation than the FBR as the S2O32- RE was recovered to 94% within 1 day after restoring the feed N/S ratio to 0.5, while it took 3 days to obtain 80% S2O32- RE in the FBR. Artificial neural network models were successfully used to predict the FBR and MBBR performance, i.e. S2O32- and NO3- RE as well as sulfate production. The SO-NR biomass from the MBBR was used to inoculate an anoxic biotrickling filter (BTF), which was studied for simultaneous treatment of H2S and NO3- containing waste streams. In the anoxic BTF, a maximum H2S elimination capacity (EC) of 19.2 g S m-3 h-1 (99% RE) was obtained at an inlet H2S load of 20.0 g S m-3 h-1 (~500 ppmv) and an N/S ratio of ~1.7. As some NO3--containing wastewaters can also contain organic compounds, the anoxic BTF inoculated with Paracoccus versutus strain MAL 1HM19 was studied for the simultaneous treatment of H2S, NO3- and organic carbon containing waste streams. With this BTF, NO3- and acetate removal rates of 16.7 g NO3--N m-3 h-1 and 42.0 g acetate m-3 h-1, respectively, were achieved, which was higher than the values observed in the BTF inoculated with the mixed culture of autotrophic SO-NR bacteria (11.1 g NO3--N m-3 h-1 and 10.2 g acetate m-3 h-1). Anoxic BTFs were operated under several transient conditions (i.e. varied gas and trickling liquid flow rates, intermittent NO3- supply and H2S shock loads) to evaluate the impacts of sudden changes that usually occur in practical applications. The different transient conditions significantly affected the H2S EC of the anoxic BTF. After applying H2S shock loads, the H2S RE fully recovered to >99% within 1.7 days after resuming normal operation. In summary, the MBBR was more effective for the removal of S2O32- than the FBR, es-pecially under nitrate limited conditions. Based on the short recovery times after expo-sure to transient-state conditions, the anoxic MBBR and BTF were found to be resilient and robust systems for removal of reduced sulfur compounds under autotrophic and mixotrophic conditions

    Energy: A continuing bibliography with indexes, issue 15

    Get PDF
    This bibliography lists 1112 reports, articles, and other documents introduced into the NASA scientific and technical information system from July 1, 1977 through September 30, 1977
    corecore