LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 9 of total 9

Search options

  1. Article ; Online: Real-Time Optimization of Pulp Mill Operations with Wood Moisture Content Variation

    Wipawadee Nuengwang / Thongchai R. Srinophakun / Matthew J. Realff

    Processes, Vol 8, Iss 651, p

    2020  Volume 651

    Abstract: In tropical countries, such as Thailand, the variation of tree moisture content can be significant based on seasonal variations in rainfall. Pulp mill operation optimization accounting for wood moisture variation was used to determine optimal operation ... ...

    Abstract In tropical countries, such as Thailand, the variation of tree moisture content can be significant based on seasonal variations in rainfall. Pulp mill operation optimization accounting for wood moisture variation was used to determine optimal operation conditions and minimize production cost. The optimization models were built using empirical modeling techniques with simulated data from the IDEAS software package. Three case studies were performed. First, a base case of nominal annual operation at a fixed production rate was used to calculate production cost that varies with wood moisture content. The second case is annual optimization where production was allowed to vary monthly over an annual cycle to minimize production cost. For the third case, real-time optimization (RTO) was used to determine optimal production rate with the wood moisture content varying every 3 days. The rolling horizon approach was used to schedule production to keep inventory levels within bounds and with a penalty applied to deviations from the annual expected values of inventory. The advantage of RTO in accounting for moisture content variation was confirmed by annual production costs results simulated for 20 years. These results statistically demonstrated that the overall cost was reduced compared to the second case of monthly production targets.
    Keywords real-time optimization ; pulp mill modeling ; rolling horizon approach ; moisture content of wood variation ; Chemical technology ; TP1-1185 ; Chemistry ; QD1-999
    Subject code 660
    Language English
    Publishing date 2020-05-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  2. Article ; Online: Defining Targets for Adsorbent Material Performance to Enable Viable BECCS Processes

    Hannah E. Holmes / Ryan P. Lively / Matthew J. Realff

    JACS Au, Vol 1, Iss 6, Pp 795-

    2021  Volume 806

    Keywords Chemistry ; QD1-999
    Language English
    Publishing date 2021-05-01T00:00:00Z
    Publisher American Chemical Society
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  3. Article ; Online: Designing the bioproduction of Martian rocket propellant via a biotechnology-enabled in situ resource utilization strategy

    Nicholas S. Kruyer / Matthew J. Realff / Wenting Sun / Caroline L. Genzale / Pamela Peralta-Yahya

    Nature Communications, Vol 12, Iss 1, Pp 1-

    2021  Volume 14

    Abstract: Returning from Mars to Earth requires propellant. The authors propose a biotechnology-enabled in situ resource utilization (bioISRU) process to produce a Mars specific rocket propellant, 2,3-butanediol, using cyanobacteria and engineered E. coli, with ... ...

    Abstract Returning from Mars to Earth requires propellant. The authors propose a biotechnology-enabled in situ resource utilization (bioISRU) process to produce a Mars specific rocket propellant, 2,3-butanediol, using cyanobacteria and engineered E. coli, with lower payload mass and energy usage compared to chemical ISRU strategies.
    Keywords Science ; Q
    Language English
    Publishing date 2021-10-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  4. Article: Adsorption Process Intensification through Structured Packing: A Modeling Study Using Zeolite 13X and a Mixture of Propylene and Propane in Hollow-Fiber and Packed Beds

    Sen, Trisha / Yoshiaki Kawajiri / Matthew J. Realff

    Industrial & engineering chemistry process design and development. 2018 Aug. 03, v. 58, no. 15

    2018  

    Abstract: There is scope to intensify the traditional adsorptive separation process which relies on packing a bed with adsorbent pellets. The hollow-fiber bed is one of the several structured configurations that have been proposed to overcome the high pressure ... ...

    Abstract There is scope to intensify the traditional adsorptive separation process which relies on packing a bed with adsorbent pellets. The hollow-fiber bed is one of the several structured configurations that have been proposed to overcome the high pressure drop and inefficient heat transfer of this random packing arrangement. While heat and mass transfer and pressure drop losses are improved in the hollow-fiber bed, the adsorbent packing density is reduced leading to a potential loss of capacity. In this computational study, we performed preliminary parametric comparisons of these bed properties, for equivalent cases in the packed bed and the hollow-fiber bed. Optimized five step single bed cycles for the separation of propylene and propane on zeolite 13X were also studied. For the same recovery and purity, the hollow-fiber bed was found to have a productivity that was five times higher than the packed bed. The hollow-fiber bed also showed higher productivity, when parameters such as the desorption pressure and the ratio of the purge to feed velocity were varied in both beds.
    Keywords adsorbents ; adsorption ; desorption ; heat transfer ; mass transfer ; models ; pellets ; process design ; propane ; propylene ; zeolites
    Language English
    Dates of publication 2018-0803
    Size p. 5750-5767.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1484436-9
    ISSN 1520-5045 ; 0888-5885
    ISSN (online) 1520-5045
    ISSN 0888-5885
    DOI 10.1021/acs.iecr.8b02189
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  5. Article: Operational planning and optimal sizing of microgrid considering multi-scale wind uncertainty

    Shin, Joohyun / Jay H. Lee / Matthew J. Realff

    Applied energy. 2017 June 01, v. 195

    2017  

    Abstract: Distributed and on-site energy generation and distribution systems employing renewable energy sources and energy storage devices (referred to as microgrids) have been proposed as a new design approach to meet our energy needs more reliably and with lower ...

    Abstract Distributed and on-site energy generation and distribution systems employing renewable energy sources and energy storage devices (referred to as microgrids) have been proposed as a new design approach to meet our energy needs more reliably and with lower carbon footprint. Management of such a system is a multi-scale decision-making problem encompassing hourly dispatch, daily unit commitment (UC), and yearly sizing for which efficient formulations and solution algorithms are lacking thus far. Its dynamic nature and high uncertainty are additional factors in limiting efficient and reliable operation. In this study, two-stage stochastic programming (2SSP) for day-ahead UC and dispatch decisions is combined with a Markov decision process (MDP) evolving at a daily timescale. The one-day operation model is integrated with the MDP by using the value of a state of commitment and battery at the end of a day to ensure longer term implications of the decisions within the day are considered. In the MDP formulation, capturing daily evolving exogenous information, the value function is recursively approximated with sampled observations estimated from the daily 2SSP model. With this value function capturing all future operating costs, optimal sizing of the wind farm and battery devices is determined based on a surrogate function optimization. Meanwhile, a multi-scale wind model consistent from seasonal to hourly is developed for the connection of the decision hierarchy across the scales. The results of the proposed integrated approach are compared to those of the daily independent 2SSP model through a case study and real wind data.
    Keywords algorithms ; batteries ; carbon footprint ; case studies ; decision making ; energy ; models ; operating costs ; planning ; renewable energy sources ; uncertainty ; wind ; wind farms
    Language English
    Dates of publication 2017-0601
    Size p. 616-633.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 2000772-3
    ISSN 0306-2619
    ISSN 0306-2619
    DOI 10.1016/j.apenergy.2017.03.081
    Database NAL-Catalogue (AGRICOLA)

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  6. Article: Applying Direct Yellow 11 to a modified Simons’ staining assay

    Kwok, Thomas T / David N. Fogg Jr / Matthew J. Realff / Andreas S. Bommarius

    Cellulose. 2017 June, v. 24, no. 6

    2017  

    Abstract: For quantification of overall fiber accessibility of lignocellulosic substrates, Direct Yellow 11 (C.I. 40000) is a suitable alternative to the discontinued Pylam Products’ dye Direct Orange 15 (C.I. 40002/40003). In this study we present a side-by- ... ...

    Abstract For quantification of overall fiber accessibility of lignocellulosic substrates, Direct Yellow 11 (C.I. 40000) is a suitable alternative to the discontinued Pylam Products’ dye Direct Orange 15 (C.I. 40002/40003). In this study we present a side-by-side comparison between the two azo-stilbene dyes. We characterize individual dye fractions and provide equations to determine individual concentrations. We present a modified Simons’ staining protocol incorporating the high molecular weight fraction of Direct Yellow 11. We perform tests on lignin, cellulosic, and lignocellulosic materials. In all tests, the two dyes perform similarly and satisfy many accessibility measurement criteria. We demonstrate that the adsorption of Direct Yellow 11 onto a substrate correlates with that substrate’s propensity for enzymatic hydrolysis. We confirm this correlation on a series of organic solvent pretreatments and on a series of lignocellulosic substrates. Finally, we outline the inherent limitations of performing adsorption experiments with Direct Yellow 11 and other high molecular weight dyes.
    Keywords adsorption ; cellulose ; dyes ; enzymatic hydrolysis ; equations ; lignin ; lignocellulose ; molecular weight ; solvents ; staining
    Language English
    Dates of publication 2017-06
    Size p. 2367-2373.
    Publishing place Springer Netherlands
    Document type Article
    ZDB-ID 1496831-9
    ISSN 1572-882X ; 0969-0239
    ISSN (online) 1572-882X
    ISSN 0969-0239
    DOI 10.1007/s10570-017-1269-y
    Database NAL-Catalogue (AGRICOLA)

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  7. Article ; Online: Economic Analysis of an Organosolv Process for Bioethanol Production

    Jesse Kautto / Matthew J. Realff / Arthur J. Ragauskas / Tuomo Kässi

    BioResources, Vol 9, Iss 4, Pp 6041-

    2014  Volume 6072

    Abstract: In a previous paper, conceptual process design, simulation, and mass and energy balances were presented for an organosolv process with a hardwood feed of 2350 metric tons (MT) per day and ethanol, lignin, furfural, and acetic acid production rates of 459, ...

    Abstract In a previous paper, conceptual process design, simulation, and mass and energy balances were presented for an organosolv process with a hardwood feed of 2350 metric tons (MT) per day and ethanol, lignin, furfural, and acetic acid production rates of 459, 310, 6.6, and 30.3 MT/day, respectively. In this paper, the investment and operating costs of the process and the minimum ethanol selling price (MESP) to make the process economically feasible were estimated. The total capital investment of the plant was approximately 720 million USD. Lignin price was found to affect the MESP considerably. With a base case lignin price of 450 USD/MT, the MESP was approximately 3.1 USD per gallon (gal). Higher lignin price of 1000 USD/MT was required to equal the MESP with the December 2013 ethanol market price (2.0 USD/gal). In addition to lignin price, the MESP was found to be strongly affected by feedstock, enzyme, and investment costs. Variations in feedstock and investment costs affected the MESP by approximately 0.2 and 0.5 USD/gal, respectively. Changing the enzyme dosage and price from base case estimate of 5270 USD/MT and 0.02 g/g cellulose to more conservative 3700 USD/MT and 0.06 g/g cellulose, respectively, increased the MESP by 0.59 USD/gal.
    Keywords Organosolv ; Economic assessment ; Pretreatment ; Bioethanol ; Lignin ; Simulation ; Chemistry ; QD1-999 ; Science ; Q
    Subject code 660
    Language English
    Publishing date 2014-08-01T00:00:00Z
    Publisher North Carolina State University
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  8. Article: Moving Beyond Adsorption Capacity in Design of Adsorbents for CO₂ Capture from Ultradilute Feeds: Kinetics of CO₂ Adsorption in Materials with Stepped Isotherms

    Darunte, Lalit A / Trisha Sen / Chiraag Bhawanani / Krista S. Walton / David S. Sholl / Matthew J. Realff / Christopher W. Jones

    Industrial & engineering chemistry process design and development. 2018 Dec. 06, v. 58, no. 1

    2018  

    Abstract: Amine-functionalized metal organic frameworks (MOFs) such as Mg₂(dobpdc) have shown some of the highest capacities for CO₂ capture under simulated direct air capture (DAC) conditions, i.e., at a CO₂ partial pressure at 0.4 mbar. The most widely studied ... ...

    Abstract Amine-functionalized metal organic frameworks (MOFs) such as Mg₂(dobpdc) have shown some of the highest capacities for CO₂ capture under simulated direct air capture (DAC) conditions, i.e., at a CO₂ partial pressure at 0.4 mbar. The most widely studied materials of this kind have adsorption isotherms whose shape is controlled by the material’s underlying cooperative adsorption mechanism for CO₂. Previous analyses of these materials, however, have focused primarily on equilibrium adsorption. Here, we study adsorption of CO₂ in amine-functionalized MOFs under ultradilute conditions relevant to DAC using a packed bed breakthrough system to understand the challenges of using these materials in practical separations. By examining the effects of flow rate, temperature, and CO₂ concentration on the observed breakthrough profiles, we show how the isotherm shape, mass transfer resistances and adsorption/desorption kinetics impact the system’s performance. An empirical model for the packed bed that accounts for the cooperative reaction mechanism for adsorption of CO₂ in N,N′-dimethyl ethylene diamine (MMEN)–Mg₂(dobpdc) is developed. The kinetics of CO₂ adsorption at CO₂ concentrations of 400 ppm are characterized through an Avrami model, while at higher CO₂ concentrations, a kinetic model based on a Michaelis–Menten expression is more successful. It is also suggested that, at low concentrations, mass transfer rate is limited by cooperative insertion of CO₂. Overall, this work has identified the system performance (i.e., rate of CO₂ extraction, CO₂ capture fraction, and breakthrough curve types) for different feed concentrations of CO₂. Critically, this work shows that the use of materials with stepped isotherm for applications such as DAC has some fundamental challenges that cannot be addressed by efforts that focus solely on modifying the overall equilibrium adsorption capacity or swing capacity.
    Keywords adsorbents ; adsorption ; air ; carbon dioxide ; desorption ; empirical models ; ethylene ; feeds ; kinetics ; mass transfer ; process design ; reaction mechanisms ; sorption isotherms ; temperature
    Language English
    Dates of publication 2018-1206
    Size p. 366-377.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1484436-9
    ISSN 1520-5045 ; 0888-5885
    ISSN (online) 1520-5045
    ISSN 0888-5885
    DOI 10.1021/acs.iecr.8b05042
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  9. Article: Protein engineering of cellulases

    Bommarius, Andreas S / Jay H Lee / Matthew J Realff / Minjeong Sohn / Yuzhi Kang

    Current opinion in biotechnology. 2014 Oct., v. 29

    2014  

    Abstract: This review covers the topic of protein engineering of cellulases, mostly after 2009. Two major trends that are identified in this work are: first, the increased importance of results from computational protein engineering to drive ideas in the field, as ...

    Abstract This review covers the topic of protein engineering of cellulases, mostly after 2009. Two major trends that are identified in this work are: first, the increased importance of results from computational protein engineering to drive ideas in the field, as experimental ideas and results often are still scarce, and, second, the further development of helper proteins for cellulose hydrolysis, such as lytic polysaccharide monooxygenase (LPO). The discussion in this work focuses both on improved attributes of cellulases and on the domains of cellulase that have been improved.
    Keywords cellulose ; endo-1,4-beta-glucanase ; hydrolysis ; protein engineering ; proteins
    Language English
    Dates of publication 2014-10
    Size p. 139-145.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1052045-4
    ISSN 1879-0429 ; 0958-1669
    ISSN (online) 1879-0429
    ISSN 0958-1669
    DOI 10.1016/j.copbio.2014.04.007
    Database NAL-Catalogue (AGRICOLA)

    Full text online

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 3071: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

To top