Transformations of citral over bifunctional Ru-H-Y-80 extrudates in a continuous reactor

Research is focused on an integrated way to simultaneously optimize the bleaching operations and subsequent wastewater treatment for pulp and paper mills. Bleach wastewaters from ClO2-bleached pulping studies at Institute of Paper Science and Technology (IPST) were used as the feed for batch reactors to test and rank the treatability and kinetics. The key aspect of the system is the use of sequential anaerobic/aerobic phases to enhance reductive dehalogenation of chloro-organic materials. Two continuous reactor systems, one operated in an anaerobic-aerobic mode and a second in an aerobic-aerobic mode, received bleaching wastewater obtained from a full-scale plant. Acclimated cultures from both continuous reactors were used to quantify the AOX (Adsorbable Organic Halide) and COD removal from various bleaching wastewaters. In general, the sequential anaerobic/aerobic treatment of bleach wastewater can improve both biotreatability and degradation rates.

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Analysis of the precipitation reactor-separation equipment system. Continuous reactor and the rotary vacuum filter operating at the selected negative pressure drop

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19812364 ◽

1981 ◽

Vol 46 (10) ◽

pp. 2364-2370 ◽

Cited By ~ 1

Author(s):

Otakar Söhnel

Keyword(s):

Pressure Drop ◽

Negative Pressure ◽

Continuous Reactor ◽

Vacuum Filter ◽

Continuous Precipitation ◽

Derived Relations ◽

Filtration Area ◽

Separation Equipment ◽

Unit Output ◽

Rotary Vacuum

An analysis has been performed of the continuous precipitation reactor - rotary vacuum filter system (operating at the selected negative pressure drop) on the basis of the unit output. Filtration area necessary for separation of the product from the precipitation reactor is a function of the mean residence time of suspension in the reactor, concentration of the precipitating solutions, porosity of the filtration cake and the filtration negative pressure drop. Application of the derived relations is demonstrated on the continuous precipitation of Mg(OH)2.

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Control of an adiabatic continuous reactor by feeding catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19802903 ◽

1980 ◽

Vol 45 (11) ◽

pp. 2903-2918 ◽

Cited By ~ 1

Author(s):

Josef Horák ◽

Zina Valášková ◽

František Jiráček

Keyword(s):

Steady State ◽

Reaction Temperature ◽

Continuous Reactor ◽

Control Element ◽

Inlet Temperature ◽

Switching Cycle ◽

Point Temperature ◽

Set Point ◽

Constant Rate ◽

Laboratory Reactor

Algorithms have been presented, analyzed and experimentally tested to stabilize the reaction temperature at constant inlet temperature and composition of the feed by controlled dispensing of the catalyst. The information for the control element is the course of the reaction temperature. If the temperature of the reaction mixture is below the set point, the catalyst is being fed into the reactor at a constant rate. If the reaction temperature is higher the catalyst dispenser is blocked; dispensing of the catalyst is not resumed until the set point temperature has been reached again. The amount of catalyst added is a function of the duration of the switching cycle. The effect has been discussed of the form of this function on the course of the switching cycle. The results have been tested experimentally on a laboratory reactor controlled in an unstable steady state.

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Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

Scientific Reports ◽

10.1038/s41598-021-95615-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

R. M. Silva ◽

A. A. Abreu ◽

A. F. Salvador ◽

M. M. Alves ◽

I. C. Neves ◽

...

Keyword(s):

Hydrogen Production ◽

Anaerobic Bacteria ◽

Dark Fermentation ◽

Inorganic Materials ◽

Biohydrogen Production ◽

High Rate ◽

Continuous Reactor ◽

Organic Loading Rate ◽

Fermentation Products ◽

Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

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