scholarly journals Design Cum Performance Equation for a Reactor Type Adsorption Unit

2009 ◽  
Vol 1 (3) ◽  
pp. 450-460
Author(s):  
M. A. Islam ◽  
M. S. I. Mozumder ◽  
M. M. R. Khan
Keyword(s):  
Conventional Method ◽  
Flow Reactor ◽  
Plug Flow ◽  
Fixed Bed ◽  
Optimal Operation ◽  
Operating Conditions ◽  
Adsorption System ◽  
Column Test ◽  
Physico Chemical ◽  
Reactor Type

The conventional method for designing a fixed bed adsorption unit has been discussed. The method is based on the data obtained from an adsorption column test. The characterization of an adsorption system, however, is performed in a laboratory batch experiment. It is shown that the conventional method does not make proper use of the physico-chemical parameters of an adsorption system determined by batch test. Also the method fails to predict the performance of an adsorption unit, if the operating condition differs from that under which the column test has been conducted for design purposes. New design equation has been proposed for both ‘Constantly Stirred Tank Reactor (CSTR)’ and ‘Plug Flow Reactor (PFR)’ type adsorption units. The equation predicts the performance of a reactor type adsorption unit under varying operating conditions. The proposed method is based only on the data obtained in batch experiment.Keywords: Adsorption; Unit design; Reactor; Optimal Operation, Dosage; Coefficient of utilization.© 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.DOI: 10.3329/jsr.v1i3.2592     J. Sci. Res. 1 (3), 450-460 (2009)

scholarly journals Oscillatory flow reactors for synthetic chemistry applications

2020 ◽  
Vol 10 (3) ◽  
pp. 475-490 ◽  
Author(s):  
Pauline Bianchi ◽  
Jason D. Williams ◽  
C. Oliver Kappe
Keyword(s):  
Mass Transfer ◽  
Oscillatory Flow ◽  
Flow Reactor ◽  
Plug Flow ◽  
Operating Conditions ◽  
Solid Particles ◽  
Flow Reactors ◽  
Liquid Systems ◽  
Suspend Solid ◽  
Biphasic Systems

Abstract Oscillatory flow reactors (OFRs) superimpose an oscillatory flow to the net movement through a flow reactor. OFRs have been engineered to enable improved mixing, excellent heat- and mass transfer and good plug flow character under a broad range of operating conditions. Such features render these reactors appealing, since they are suitable for reactions that require long residence times, improved mass transfer (such as in biphasic liquid-liquid systems) or to homogeneously suspend solid particles. Various OFR configurations, offering specific features, have been developed over the past two decades, with significant progress still being made. This review outlines the principles and recent advances in OFR technology and overviews the synthetic applications of OFRs for liquid-liquid and solid-liquid biphasic systems.

Comparative evaluation of critical operating conditions for a tubular catalytic reactor using thermal sensitivity and loss-of-stability criteria

2010 ◽  
Vol 64 (4) ◽  
Author(s):  
Gheorghe Maria ◽  
Dragoş-Nicolae Ştefan
Keyword(s):  
Thermal Sensitivity ◽  
Fixed Bed ◽  
Optimal Operation ◽  
Operating Conditions ◽  
Raw Material ◽  
System Stability ◽  
Performance Criteria ◽  
Matrix Analysis ◽  
Critical Conditions ◽  
Catalytic Reactor

AbstractOptimal operation of a chemical reactor according to various performance criteria often drives the system towards critical boundaries. Thus, precise evaluation of runaway limits in the parametric space becomes a crucial problem not only for the reactor’s safe operation, but also for over-designing the system. However, obtaining an accurate estimate for operating limits is a difficult task due to the limited validity of kinetic models describing complex processes, as well as the inherent fluctuations of the system’s properties (catalyst, raw-material quality). This paper presents a comparison of several effective methods of deriving critical conditions for the case of a tubular fixed-bed catalytic reactor used for aniline production in the vapour phase. Even though the methods being compared are related to one another, the generalised sensitivity criterion of Morbidelli-Varma (MV) seems to be more robust, not depending on a particular parameter being perturbed, when compared to the criteria that detect an incipient loss of system stability in the critical region (i.e., div-methods based on the system’s Jacobian and Green’s function matrix analysis). Combined application of div- and MV criteria allows for an accurate evaluation of the distance from the reactor’s nominal conditions to the safety limits.

Uncertainty Quantification of NOx Emission Due to Operating Conditions and Chemical Kinetic Parameters in a Premixed Burner

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Sajjad Yousefian ◽  
Gilles Bourque ◽  
Rory F. D. Monaghan
Keyword(s):  
Sensitivity Analysis ◽  
Uncertainty Quantification ◽  
Gas Turbine ◽  
Flow Reactor ◽  
Epistemic Uncertainty ◽  
Plug Flow ◽  
Chemical Kinetic ◽  
Operating Conditions ◽  
Nox Emission ◽  
Gas Turbine Combustion

Many sources of uncertainty exist when emissions are modeled for a gas turbine combustion system. They originate from uncertain inputs, boundary conditions, calibration, or lack of sufficient fidelity in a model. In this paper, a nonintrusive polynomial chaos expansion (NIPCE) method is coupled with a chemical reactor network (CRN) model using Python to quantify uncertainties of NOx emission in a premixed burner. The first objective of uncertainty quantification (UQ) in this study is development of a global sensitivity analysis method based on the NIPCE method to capture aleatory uncertainty on NOx emission due to variation of operating conditions. The second objective is uncertainty analysis (UA) of NOx emission due to uncertain Arrhenius parameters in a chemical kinetic mechanism to study epistemic uncertainty in emission modeling. A two-reactor CRN consisting of a perfectly stirred reactor (PSR) and a plug flow reactor (PFR) is constructed in this study using Cantera to model NOx emission in a benchmark premixed burner under gas turbine operating conditions. The results of uncertainty and sensitivity analysis (SA) using NIPCE based on point collocation method (PCM) are then compared with the results of advanced Monte Carlo simulation (MCS). A set of surrogate models is also developed based on the NIPCE approach and compared with the forward model in Cantera to predict NOx emissions. The results show the capability of NIPCE approach for UQ using a limited number of evaluations to develop a UQ-enabled emission prediction tool for gas turbine combustion systems.

A Strategy of Reactant Mixing in Methane Direct-Fired sCO2 Combustors

2018 ◽  
Author(s):  
K. R. V. Manikantachari ◽  
Scott Martin ◽  
Ladislav Vesely ◽  
Jose O. Bobren-Diaz ◽  
Subith Vasu ◽  
...  
Keyword(s):  
Power Generation ◽  
Flow Reactor ◽  
Plug Flow ◽  
Kinetic Mechanism ◽  
Operating Conditions ◽  
Lean Burn ◽  
Initial Portion ◽  
Cross Sectional ◽  
Power Cycles ◽  
Stirred Reactor

The sCO2 power cycle concept is identified as a potentially efficient, economical, and pollutant free power generation technique for future power generation. Recent work in the literature provides some strategies and best operating conditions for direct-fired sCO2 combustors based on zero-dimensional reactor modeling analysis, however there is a need for a detailed investigation using accurate combustion chemical kinetics and thermophysical models. Here, the sCO2 combustor is modelled by coupling perfectly stirred reactor (PSR) and plug flow reactor (PFR) models. The real gas effects are incorporated using the Soave-Redlich-Kwong (SRK) equation of state. Also, the detailed Aramco 2.0 kinetic mechanism is used for the combustion kinetic rates. It is found that the primary zone must be diluted either with thirty or forty-five percent of the total CO2 in the cycle to have a feasible combustor design. However, the forty-five percent dilution level at 950 K and 1000 K yielded a better consumption of CO, O2 and CH4. Also, the cross-sectional area of the sCO2 combustor can be scaled-down to 10 to 20 times smaller than a traditional combustor with the same power output. Further, from this investigation, it is also recommended to have a gradually increasing secondary dilution in the dilution zone, by using progressively larger diameter holes. This design would help retain relatively high temperature in the initial portion of the dilution zone and would help consume fuel species such as, CO and CH4. It appears that, for sCO2 combustors “lean burn” is the better strategy over stoichiometric burning to eliminate CO build up at the combustor exit. The lean burn condition at equivalence ratio (ϕ) equal to 0.9 is recommended for sCO2 combustor operation. Also, the length of the dilution zone can be scaled-down to 50% by lean burn operation of the combustor. It is also observed that the lean burn increases the net turbine power. Current work provides crucial design considerations for the development of advanced sCO2 combustors to be used with direct-fired power cycles.

Surface Modification of Nanocrystalline Zeolite X and Its Application as Catalyst in Synthesis of Cumene in a Packed Bed Flow Reactor: A Kinetic Study

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Ruchika Thakur ◽  
Sanghamitra Barman ◽  
Gopinath Halder
Keyword(s):  
Crystal Size ◽  
Flow Reactor ◽  
Plug Flow ◽  
Fixed Bed ◽  
Packed Bed ◽  
Product Distribution ◽  
Ceric Ammonium Nitrate ◽  
Zeolite X ◽  
Kinetic Rate ◽  
Nano Crystalline

AbstractIn the present investigation, synthesis of cumene by transalkylation of 1, 4 DIPB with benzene was studied over cerium modified nano crystalline zeolite X in a fixed bed plug flow reactor. Nano crystalline zeolite X was synthesized and characterized by XRD, SEM, TPD, EDS and FTIR. A series of nanocrystalline zeolite X (MX4, MX6, MX10) modified with ceric ammonium nitrate of different concentrations (4 %, 6 %, 10 %) was used for synthesis of cumene. MX10zeolite was proved to be the most active catalyst over which 27.12 % yield of cumene was obtained at temperature 553K, benzene/1, 4 DIPB mole ratio of 7.5 and space time-10.54 kg h/kmol. Reduction of crystal size (100–500 nm) in MX10increases surface area (633m2/gm) and thereby increases cumene yield. A kinetic rate equation was developed from the product distribution pattern following Langmuir–Hinshelwood approach. Kinetic parameters were estimated by nonlinear regression analysis. The activation energy for transalkylation and isomerisation reaction was found to be 88.86 kJ/mol and 99.04 kJ/mol respectively.

scholarly journals Solution and Parameter Identification of a Fixed-Bed Reactor Model for Catalytic CO2 Methanation Using Physics-Informed Neural Networks

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1304
Author(s):  
Son Ich Ngo ◽  
Young-Il Lim
Keyword(s):  
Neural Networks ◽  
Reaction Kinetics ◽  
Flow Reactor ◽  
Plug Flow ◽  
Fixed Bed ◽  
Effectiveness Factor ◽  
Fixed Bed Reactor ◽  
Reactor Model ◽  
Co2 Methanation ◽  
Chemical Reaction Kinetics

In this study, we develop physics-informed neural networks (PINNs) to solve an isothermal fixed-bed (IFB) model for catalytic CO2 methanation. The PINN includes a feed-forward artificial neural network (FF-ANN) and physics-informed constraints, such as governing equations, boundary conditions, and reaction kinetics. The most effective PINN structure consists of 5–7 hidden layers, 256 neurons per layer, and a hyperbolic tangent (tanh) activation function. The forward PINN model solves the plug-flow reactor model of the IFB, whereas the inverse PINN model reveals an unknown effectiveness factor involved in the reaction kinetics. The forward PINN shows excellent extrapolation performance with an accuracy of 88.1% when concentrations outside the training domain are predicted using only one-sixth of the entire domain. The inverse PINN model identifies an unknown effectiveness factor with an error of 0.3%, even for a small number of observation datasets (e.g., 20 sets). These results suggest that forward and inverse PINNs can be used in the solution and system identification of fixed-bed models with chemical reaction kinetics.

Uncertainty Quantification of NOx Emission due to Operating Conditions and Chemical Kinetic Parameters in a Premixed Burner

2018 ◽  
Author(s):  
Sajjad Yousefian ◽  
Gilles Bourque ◽  
Rory F. D. Monaghan
Keyword(s):  
Sensitivity Analysis ◽  
Uncertainty Quantification ◽  
Gas Turbine ◽  
Flow Reactor ◽  
Epistemic Uncertainty ◽  
Plug Flow ◽  
Chemical Kinetic ◽  
Operating Conditions ◽  
Nox Emission ◽  
Gas Turbine Combustion

Many sources of uncertainty exist when emissions are modelled for a gas turbine combustion system. They originate from uncertain inputs, boundary conditions, calibration, or lack of sufficient fidelity in the model. In this paper, a non-intrusive polynomial chaos expansion (NIPCE) method is coupled with a chemical reactor network (CRN) model using Python to rigorously quantify uncertainties of NOx emission in a premixed burner. The first objective of the uncertainty quantification (UQ) in this study is development of a global sensitivity analysis method based on NIPCE to capture aleatory uncertainty due to the variation of operating conditions and input parameters. The second objective is uncertainty analysis of Arrhenius parameters in the chemical kinetic mechanism to study the epistemic uncertainty in the modelling of NOx emission. A two-reactor CRN consisting of a perfectly stirred reactor (PSR) and a plug flow reactor (PFR) is constructed in this study using Cantera to model NOx for natural gas at the relevant operating conditions for a benchmark premixed burner. UQ is performed through the use of a number of packages in Python. The results of uncertainty and sensitivity analysis using NIPCE based on point collocation method (PCM) are then compared with the results of advanced Monte Carlo simulation (MCS). Surrogate models are also developed based on the NIPCE approach and compared with the forward model in Cantera to predict NOx emissions. The results show the capability of NIPCE approach for UQ using a limited number of evaluations to develop a UQ-enabled emission prediction tool for gas turbine combustion systems.

scholarly journals TOWARDS KINETIC REGIME OF REVERSE FLOW OPERATION

2018 ◽  
Vol 4 (3) ◽  
pp. 322
Author(s):  
Yogi Budhi
Keyword(s):  
Steady State ◽  
Flow Reactor ◽  
Switching Time ◽  
Reverse Flow ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Kinetic Regime ◽  
Steady State Operation ◽  
Reverse Flow Reactor

An analysis of reverse flow operation and its experimental study for ammonia oxidation to produce either N2, N2O, and NO have been carried out. An experimental set-up of reverse flow reactor was constructed for a laboratory scale. The experiment under steady state operation was performed as a base case in order to judge the potential during the reverse flow operation. Aim was to investigate the behavior of reverse flow operation and to observe the reactor performance. Focus was on the comparison of the steady state and reverse flow operations. The experiments show that the behavior of reverse flow reactor is strongly influenced by the ratio of the switching time over the residence time. The ammonia conversion during the regular reverse flow operation shows lower values compared to the steady state operation which is even worse during asymmetric mode. The product distributions may change under flow reversal, depending on the operating conditions, regime of operation, and operation mode.Keywords : Reverse Flow Operation, Fixed Bed Reactor, Selectivity Manipulation, Steady State Operation, Ammonia OxidationAbstrak Sebuah analisis operasi aliran bolak-balik dan studi eksperimental oksidasi amoniak untuk menghasilkan baik N2., N2O, dan NO telah dilakukan. Sebuah perangkat eksperimen reaktor aliran bolak-balik dikonstruksi untuk skala laboratorium. Eksperimen dalam operasi keadaan tunak dilakukan sebagai kasus dasar untuk menilai potensi operasi aliran bolak-balik. Tujuan penelitian ini adalah untuk meneliti kelakuan operasi aliran bolak-balik dan untuk mengamati kinerja reaktor. Kajian ini dititikberatkan pada perbandingan operasi keadaan tunak dan operasi aliran bolak-balik. Hasil percobaan menunjukkan bahwa kelakuan reaktor aliran bolak-balik sangat dipengaruhi oleh nisbah waktu pembalikan arah aliran (switching time) terhadap waktu tinggal. Konversi amomiak dalam operasi aliran bolak-balik menunjukkan nilai yang lebih rendah dibandingkan dengan operasi keadaan tunak dan dalam mode asimetrik konversinya bahkan lebih rendah lagi. Distribusi produk dapat berubah dalam pembalikan aliran yang bergantung pada kondisi-kondisi operasi, daerah operasi, dan mode operasi.Kata Kunci : Operasi Aliran Bolak-balik, Reaktor Fixed Bed, Manipulasi Selektivitas, Operasi Tunak, Oksidasi Amoniak

scholarly journals Gasification of grapevine pruning waste in an entrained-flow reactor: gas products, energy efficiency and gas conditioning alternatives

2013 ◽  
Vol 12 (2) ◽  
pp. 215-227
Keyword(s):  
Flow Reactor ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Biomass Energy ◽  
Effect Of Temperature ◽  
Producer Gas ◽  
Heating Value ◽  
Entrained Flow ◽  
Entrained Flow Reactor ◽  
Cold Gas

Owing to its higher efficiency and versatility, gasification is seen as a necessary evolution in the development of biomass energy systems. This technology has been primarily tested in fixed bed (updraft and downdraft) and fluidised bed reaction systems, with less information available about the potential of entrained-flow reactors. This latter design benefits from a relatively simple mechanical structure, robustness against severe gasification conditions and also reduced investment and operating costs. This paper describes the development of a pilot scale entrained-flow reactor and evaluates its performance in the gasification of wood waste left over from the pruning of grapevine (Vitis vinifera). The original biomass was initially analysed for its chemical composition and thermal behaviour. A series of gasification trials were conducted to evaluate the effect of temperature and relative biomass/air ratio (Frg) on the yield, composition, heating value of the resulting syngas. The cold gas efficiency of the system was determined for different operating conditions from the heating value and yields of the resulting producer gas. The results showed that the use of higher temperatures caused a small increase in overall gas yields (from 1.76 Nm3 kg-1 at 750ºC to 1.96 Nm3 kg-1 at 1050ºC) and a notable rise in its heating value (from 3.65 MJ kg-1 at 750ºC to 4.95 MJ kg-1 at 1050ºC), primarily derived from an increase in the concentration of hydrogen. The experimental results show a reduction in the fuel properties of the producer gas when using biomass/air ratios (Frg) below 2.5, which was attributed to the partial combustion of the producer gas. However, this effect was largely counteracted by the production of higher gas yields (3.39 Nm3 kg-1 for Frg = 2.16 compared to 1.96 Nm3 kg-1 for Frg = 4.05), owing to the higher conversion of the fuel at low biomass/air ratios. Optimum gasification conditions (cold gas efficiency up to 83.06 %) were reached when using high reaction temperatures (1050ºC) and low Frg (2.19). This paper also provides a final review about the formation of unwanted tars and particulates in gasification processes, its effect in energy applications, and the use of alternative technologies (thermocatalytic cracking, reforming, water-gas shift) for the conditioning and upgrading of the resulting gas stream.

scholarly journals Advanced Study of Promoted Pt /SAPO-11 Catalyst for Hydroisomerization of the n-Decane Model and Lube Oil

2021 ◽  
Vol 22 (2) ◽  
pp. 17-26
Author(s):  
Haider Aljendeel ◽  
Hussein Qasim Hussein
Keyword(s):  
Pour Point ◽  
Flow Reactor ◽  
Viscosity Index ◽  
Plug Flow ◽  
Fixed Bed ◽  
Space Velocity ◽  
Lubricating Oil ◽  
Bet Surface Area ◽  
Isomerization Reaction ◽  
Base Oil

   SAPO-11 is synthesized from silicoaluminophosphate in the presence of di-n-propylamine as a template. The results show that the sample obtained has good crystallinity, 396m2/g BET surface area, and 0.35 cm3/g pore volume. The hydroisomerization activity of (0.25)Pt (1)Zr (0.5)W/SAPO-11 catalyst was determined using n-decane and base oil. All hydroisomerization experiments of n-decane were achieved at a fixed bed plug flow reactor at a temperature range of 200-275°C and  LHSV 0.5-2h-1.  The results show that the n-decane conversion increases with increasing temperature and decreasing LHSV, the maximum conversion of 66.7 % was achieved at temperature 275°C and LHSV of 0.5 h-1. Meanwhile, the same catalyst was used to improve base oil specification by increasing viscosity index and decreasing pour point. The isomerization reaction conditions, employed are temperature (200-300)ºC, the liquid hourly space velocity of 0.5-2h-1, and the pressure kept atmospheric. The present study shows that Pt Zr W/SAPO-11 minimizes the pour point of lubricating oil to -16°C at isomerization temperature of  300°C and LHSV of 0.5 h-1 and viscosity index 134.8.

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