Extremum-seeking with variable gain control for intensifying biogas production in anaerobic fermentation

2006 ◽  
Vol 53 (4-5) ◽  
pp. 35-44 ◽  
Author(s):  
J. Liu ◽  
G. Olsson ◽  
B. Mattiasson
Keyword(s):  
Anaerobic Fermentation ◽  
Biogas Production ◽  
Scale Up ◽  
Fixed Bed ◽  
Gain Control ◽  
Extremum Seeking ◽  
High Rate ◽  
Fixed Bed Reactor ◽  
Variable Gain ◽  
True Value

A state-dependent variable-gain control system is implemented to follow the characteristics of a laboratory-scale up-flow anaerobic fixed-bed reactor dynamically. The transition from one state to another is determined on an hourly basis, depending on difference between the setpoint of the reactor pH and its true value. Considerable improvement of the process stability – reduction of oscillation in both the reactor pH and biogas production rate during high-rate operation, has been achieved, although the control structure is simple and intuitive.

Design of a continuous flow immobilized-cell reactor for biosynthetical production of L-aspartic acid

1985 ◽  
Vol 50 (10) ◽  
pp. 2122-2133 ◽  
Author(s):  
Jindřich Zahradník ◽  
Marie Fialová ◽  
Jan Škoda ◽  
Helena Škodová
Keyword(s):  
Aspartic Acid ◽  
Continuous Flow ◽  
Immobilized Cells ◽  
Scale Up ◽  
Fixed Bed ◽  
Packed Bed ◽  
Fixed Bed Reactor ◽  
Experimental Program ◽  
Design Parameters ◽  
Immobilized Cell

An experimental study was carried out aimed at establishing a data base for an optimum design of a continuous flow fixed-bed reactor for biotransformation of ammonium fumarate to L-aspartic acid catalyzed by immobilized cells of the strain Escherichia alcalescens dispar group. The experimental program included studies of the effect of reactor geometry, catalytic particle size, and packed bed arrangement on reactor hydrodynamics and on the rate of substrate conversion. An expression for the effective reaction rate was derived including the effect of mass transfer and conditions of the safe conversion-data scale-up were defined. Suggestions for the design of a pilot plant reactor (100 t/year) were formulated and decisive design parameters of such reactor were estimated for several variants of problem formulation.

scholarly journals Evaluation of Fixed-Bed Cultures with Immobilized Lactococcus Lactis ssp. Lactis on Different Scales

2017 ◽  
Vol 11 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Rebecca Faschian ◽  
Ilyas Eren ◽  
Steven Minden ◽  
Ralf Pörtner
Keyword(s):  
Dilution Rate ◽  
Lactococcus Lactis ◽  
Scale Up ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Fixed Bed Reactor ◽  
Batch Mode ◽  
Promising Alternative ◽  
Fixed Beds ◽  
Pilot Scale Reactor

Fixed-bed processes, where cells are immobilized within macroporous carriers, are a promising alternative to processes with suspended cells. A scale-up concept is presented in order to evaluate the performance as part of process design of fixed-bed processes. Therefore,Lactococcus lactiscultivation in chemostat and batch mode was compared to fixed bed cultures on three different scales, the smallest being the downscaledMultifermwith 10 mL fixed bed units, the second a 100 mL fixed-bed reactor and the third a pilot scale reactor with 1 L fixed bed volume. As expected, the volume specific lactate productivity of all cultivations was dependent on dilution rate. In suspension chemostat culture a maximum of 2.3 g·L-1·h-1was reached. Due to cell retention in the fixed-beds, productivity increased up to 8.29 g·L-1·h-1at a dilution rate of D = 1.16 h-1(corresponding to 2.4·µmax) on pilot scale. For all fixed bed cultures a common spline was obtained indicating a good scale-up performance.

scholarly journals A Radial Flow Contactor for Ambient Air CO2 Capture

2020 ◽  
Vol 10 (3) ◽  
pp. 1080 ◽  
Author(s):  
Qian Yu ◽  
Wim Brilman
Keyword(s):  
Radial Flow ◽  
Flow Reactor ◽  
Operation Mode ◽  
Scale Up ◽  
Fixed Bed ◽  
Ambient Air ◽  
Fixed Bed Reactor ◽  
Batch Mode ◽  
Radial Flow Reactor ◽  
Continuous Application

Direct air capture (DAC) of CO2 can address CO2 emissions from distributed sources and produce CO2 from air virtually anywhere that it is needed. In this paper, the performance of a new radial flow reactor (RFR) for CO2 adsorption from ambient air is reported. The reactor uses a supported amine sorbent and is operated in a batch mode of operation or semi-continuously, respectively without or with sorbent circulation. The radial flow reactor, containing 2 kg of the adsorbent, is successfully scaled up from the experimental results obtained with a fixed bed reactor using only 1 g of the adsorbent. In the batch operation mode, the sorbent in the annular space of the RFR is regenerated in situ. With sorbent circulation, the RFR is loaded and unloaded batchwise and only used as an adsorber. A sorbent batch loaded with CO2 is transported to and regenerated in an external (fluid bed) regenerator. The RFR unit is characterized by a low contacting energy (0.7–1.5 GJ/ton-CO2) and a relatively short adsorption time (24–43 min) compared to other DAC processes using the same types of sorbents. The contactor concept is ready for further scale-up and continuous application.

Modeling NOx Adsorption onto Fe/ZSM-5 Catalysts in a Fixed Bed Reactor

2013 ◽  
Vol 11 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Xingxing Cheng ◽  
Xiaotao T. Bi
Keyword(s):  
Circulating Fluidized Bed ◽  
Scale Up ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Axial Dispersion ◽  
No Oxidation ◽  
Fixed Bed Reactor ◽  
Model Parameters ◽  
Adsorption Model ◽  
Nox Adsorption

Abstract A NOx adsorption kinetic model including NO oxidation and adsorption was developed. The NOx and O2 adsorption experimental data from a fixed bed were found to be fitted well to the Freundlich type isotherm. An axial dispersion adsorption model was then developed to simulate the breakthrough curve for NOx adsorption in the fixed bed. The model parameters including mass transfer coefficient and axial dispersion coefficient were fitted from the NOx breakthrough curves measured in a fixed bed. This model can be used for design and scale-up of fixed bed NOx adsorption columns. It can also be extended for the modeling of NOx adsorption in the annulus region of the circulating fluidized bed reactor for catalytic reduction of NOx.

Scale up and stability test for oxidative coupling of methane over Na2WO4-Mn/SiO2 catalyst in a 200 ml fixed-bed reactor

2008 ◽  
Vol 17 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Haitao Liu ◽  
Xiaolai Wang ◽  
Dexin Yang ◽  
Runxiong Gao ◽  
Zhonglai Wang ◽  
...  
Keyword(s):  
Oxidative Coupling ◽  
Scale Up ◽  
Fixed Bed ◽  
Oxidative Coupling Of Methane ◽  
Stability Test ◽  
Fixed Bed Reactor

scholarly journals Produksi Biogas dari Limbah Cair Kelapa Sawit dengan Menggunakan Reaktor Unggun Tetap tanpa Proses Pretreatment

2021 ◽  
Vol 22 (1) ◽  
pp. 078-084
Author(s):  
Wiharja Wiharja ◽  
Widiatmini Sih Winanti ◽  
Prasetiyadi Prasetiyadi ◽  
Amita Indah Sitomurni
Keyword(s):  
Palm Oil ◽  
Biogas Production ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Organic Substrates ◽  
Biogas Yield ◽  
Alternative Processing ◽  
Reactor Technology ◽  
Thermophilic Conditions ◽  
Potential Resource

ABSTRACT Palm Oil Mill Effluent (POME) resulted from the palm oil industry is a potential resource for biogas production. In this study, POME was processed by utilizing microbes in an anaerobic condition using a fixed bed reactor. This study aimed at providing alternative processing of POME into biogas at the most optimum biogas yield without any pretreatment, taking advantage of POME conditions generated from the production process at the average temperature of 55 – 60 °C. In the anaerobic process, temperature conditions have a significant effect on bacteria's performance to degrade organic matter. In thermophilic conditions, bacteria deteriorate organic substrates more actively than in mesophilic states. This research proved that using fixed bed reactor technology to treat POME without pretreatment has generated biogas at the yield of 25.43 liters/liter of POME production. Applying this technology also demonstrated that investment and operating costs are cheaper due to having no mixing tank and fewer chemicals applications for the neutralization process. Keywords: biogas, fixed bed reactor, POME, pretreatment, thermophilic   ABSTRAK Proses pengolahan POME dapat dilakukan dengan menggunakan proses fermentasi anaerobik yaitu memanfaatkan kerja bakteri anaerobik untuk memproduksi biogas. Penelitian ini bertujuan memberikan alternatif pengelolaan limbah cair pabrik kelapa sawit yang dapat menghasilkan biogas yang paling optimal tanpa melakukan pretreatment. Proses yang dipilih disesuaikan dengan kondisi panas POME yang keluar proses yaitu sekitar 55 - 60 oC. Kondisi temperatur sangat berpengaruh nyata terhadap kinerja bakteri pendegradasi bahan organik di dalam limbah cair dalam proses anaerobik. Pada kondisi termofilik bakteri lebih aktif dibandingkan pada kondisi mesofilik. Melalui penelitian ini, dapat diketahui bahwa dengan menggunakan teknologi reaktor fixed bed untuk mengolah POME tanpa adanya pretreatment, biogas tetap dapat diperoleh dengan perolehan rata rata 25,43 liter per liter POME. Dengan menggunakan teknologi ini biaya investasi dan operasi akan lebih murah dikarenakan tidak memerlukan bak pencampur dan penggunaan bahan kimia untuk proses netralisasi. Kata kunci: Biogas, reaktor fixed bed, POME, pretreatment, termofilik

Effect of different neutralizing treatments on the efficiency of an anaerobic digester fed with deproteinated cheese whey

1986 ◽  
Vol 53 (3) ◽  
pp. 467-476 ◽  
Author(s):  
Johannes De Haast ◽  
Trevor J. Britz ◽  
Johannes C. Novello
Keyword(s):  
Biogas Production ◽  
Fixed Bed ◽  
Oxygen Demand ◽  
Ph Control ◽  
Control Measures ◽  
Fixed Bed Reactor ◽  
Stable Conditions ◽  
Complete Failure ◽  
Carbon Balances ◽  
The Stability

SUMMARYDeproteinated whey, prepared from sweet whey powder, was digested anaerobically in a downflow fixed-bed reactor at 35 °C. Different pH control treatments were applied over a period of 210 d. Initially NaOH was added at a concentration of 68 mequiv. l-1 substrate. This was successfully replaced by 80 mequiv. Na2CO3l-1 which resulted in a 15·5% increase in biogas production and a 6·7% increase in CH4 production. A decrease in the quantity of Na2C03l-1 added led to signs of instability and a drop in CH4 production. The stepwise addition of urea restored the stability, and a further increase of urea, to a level of about 20 mequiv. l-1, made it possible to replace Na2C03 completely. When all pH control measures were omitted, complete failure resulted within 10 d. Methane yields, under stable conditions, varied between 0·321 and 0·272 m3 kg-1 chemical oxygen demand (COD) removed which corresponds to 92 and 78% of the theoretical yields. Carbon balances indicated that between 60·8 and 68·5% of the carbon fed was converted to biogas. No toxicity was observed at a carbon: nitrogen (C/N) ratio of 7·7. This was in contrast to previous results where toxicity had occurred at the same C/N ratio but at a higher concentration of Na.

Anaerobic digestion of deproteinated cheese whey

1985 ◽  
Vol 52 (3) ◽  
pp. 457-467 ◽  
Author(s):  
Johannes De Haast ◽  
Trevor J. Britz ◽  
Johannes C. Novello ◽  
Emilige W. Verwey
Keyword(s):  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Fixed Bed ◽  
Oxygen Demand ◽  
Ammonia Level ◽  
Fixed Bed Reactor ◽  
Total Carbon ◽  
Ammonia Toxicity ◽  
Biogas Yield ◽  
Titration Curves

SUMMARYWhey and deproteinated whey preparations with different carbon: nitrogen (C/N) ratios ranging from 7·5 to 73 were digested anaerobically in a downflow stationary fixed-bed reactor at 35 °C with a hydraulic retention time of 5 d. Effluent and biogas parameters indicated that no decrease in digestion and stability occurred at the highest C/N ratio. Chemical oxygen demand (COD) removal averaged 88%, while volatile fatty acids were maintained at a low level (< 500 mg l–1). Biogas yield averaged 0·423 m3kg–1COD and the methane content of the biogas varied between 57 and 63%. Ammonia toxicity occurred at a C/N ratio of 7/5 in the substrate feed. Virtually no ammonia N was detected in the effluent when whey substrates with C/N ratios of 50 and 73 were fed. Titration curves showed that buffer intensities in the effluent were not affected by a decrease in ammonia level. A decrease in the biomass content of the effluent which occurred as a result of the increase in C/N ratio of the substrate did not cause any rate limiting effect on biogas production. The removal of protein from the whey caused a reduction in the ratio of COD: total carbon in the whey. On average 59% of the carbon in the substrate was converted to biogas.

scholarly journals Cementation of Cd Ions on Zinc Using a Rotating Fixed Bed Impeller Basket Reactor

2021 ◽  
pp. 41-50
Author(s):  
Yousra Hamdy Farid
Keyword(s):  
Mass Transfer ◽  
Rotational Speed ◽  
Rotation Speed ◽  
Initial Period ◽  
Scale Up ◽  
Fixed Bed ◽  
High Rate ◽  
Waste Solution ◽  
System A ◽  
Ring Diameter

Cementation or metal displacement reaction is one of the most effective techniques for removing toxic metals from industrial waste solutions. Aims: The main purpose of this work is to study the rate of cementation of cadmium by using a rotating bed of Zn Raschig rings packed in a perforated impeller basket for the investigation of the removal of Cd 2+ from waste solution. Study Design: The reactor was tested for Cd2+ concentration removed, the diameter of Zinc Raschig rings, and the rotational speed of the basket. Methodology: The results indicate that there are two rates of cementation for Cd-Zn system, a high rate at the beginning, followed by a lower rate after the initial period. The results also show that percentage removal of Cd2+ ions from solution increases by increasing the speed of basket rotation, and as the diameter of Zn Raschig ring packed in the basket reactor, increases the removal of Cd2+ decreases. The cadmium deposits on zinc as powder. Results: The removal of Cd2+ is optimum for ring diameter of 0.5 cm, initial concentration of 100 ppm, and basket rotation speed of 500 rpm. The experimental data fit the following equation: Sh=0.041 Sc0.33Re0.40. This equation can be used for the design scale-up and operation of reactors used to remove Cd2+ from wastewater by cementation. Conclusion: Rates of cementation were expressed in terms of the rate of mass transfer, the mass transfer coefficient increases as the rotational speed of the basket increases.

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