Deepak Kunzru

Indian Institute of Technology Kanpur | IIT Kanpur · Department of Chemical Engineering

Deep eutectic solvents(DES) are eutectic mixtures of hydrogen bond acceptors and hydrogen bond donors.The stability of DES depends on the nature of interatomic interactions during their structural formation.This study focuses on the structural analysis of choline chloride(ChCl)-urea DES system(molar ratio 1:2) at the atomic level using density func...

As the need of the hour, it is imperative to develop highly active HDS catalyst capable of desulfurizing refractory organic sulfur compounds (DBT; 4, 6 DMDBT etc.). In comparison to well established bimetallic catalysts (e.g. NiMo/NiW), trimetallic catalysts exhibit synergistic effect between active metal species which promotes both direct desulfur...

The kinetics of the steam reforming of methane was studied on 0.5 wt% Rh–15 wt% Ni/MgAl2O4 catalyst. The variation of methane conversion with contact time (\({\text{W}}/{\text{F}}_{{{\text{CH}}_{4} ,0}}\)) was recorded in the temperature range of 450 to 600 °C, at three different pressures of 1, 4 and 6 bar, and at steam to carbon ratio (S/C) of 2,...

Ni-promoted WS2 catalysts are preferred over Ni/Co promoted MoS2 catalysts due to their enhanced HDS catalytic capability towards methylated dibenzothiophene compounds. However, it is challenging to prepare the active Ni-promoted WS2 phase with optimal number of edge/brim sites because WO3 and NiO have different sulfidation temperatures, which favo...

The effect of adding small amounts Rh noble metal to 15 wt.% Ni/MgAl2O4 catalyst were studied for the steam reforming of methane. For this purpose, two series of catalysts were prepared and then the most active catalyst from this study was selected for metal monolith application. Both series of catalysts were tested at ambient and high pressures co...

Effect of addition of Pt noble metal to Ni/MgAl2O4 catalyst for steam reforming of methane was studied at atmospheric pressure and at high pressure (10 bar). Pt loading of the catalyst was varied from 0.01 wt.% to 1.0 wt.%. Catalyst characterization studies showed that the degree of reduction of the catalyst increased from 44.9% for Ni/MgAl2O4 to 6...

In this study, the effect of different process variables on the washcoating of Ni/MgAl2O4 on FeCralloy foils and monoliths has been investigated and the washcoated monolith tested for the steam reforming of methane. Washcoating parameters, such as calcination temperature after washcoating, addition of binders, particle size of the slurry after ball...

The effect of adding ceria and nickel to Pt/γ-Al2O3 catalyst was studied for preferential oxidation (PROX) of CO. The catalysts were characterized by XRD, BET, TPR, XRF and H2 chemisorption techniques. An optimum amount of ceria and nickel was required for improving the activity and selectivity. Adding small amount of ceria (1 wt. %) and/or nickel...

In this paper, we report the synthesis of ultrasmall Co-promoted MoO3 nanoclusters (∼2 nm) supported over γ-Al2O3 possessing an increased number of Mo edge atoms, using colloidal synthesis for hydrodesulfurization reaction. A three-step synthesis methodology was followed: in the first step, Co-promoted MoO3 nanoclusters (∼2 nm) were synthesized usi...

In this study, the effect of calcination temperature on the physico-chemical properties of Ni/MgAl2O4 as well as on the activity and stability of the catalyst for steam reforming of methane has been investigated. The catalyst calcination temperature was varied from 350 °C to 1000 °C while the reactor pressure was varied from 1 to 10 bar at 600 °C....

In this study, we report the synthesis of ultrasmall NiMo bimetallic metal oxide nanoclusters (~2nm), supported on γ-Al2O3 for hydrodesulfurization reaction. The metal oxide nanoclusters were prepared by colloidal synthesis using oleic acid and oleylamine as ligands, followed by incorporation of nanoclusters into the pores of γ-Al2O3. The nanoclust...

Hydrodesulfurization of dibenzothiophene, dissolved in n-hexadecane, was conducted in the temperature range of 548-593 K at 10 MPa pressure in a conventional packed bed reactor for two different catalyst sizes and on monoliths washcoated with different metal loadings. The monolith catalysts were made by washcoating using NiMo/γ-Al2O3 catalysts prep...

The continuously increasing demand for clean and renewable energy warrants the development of renewable, nonpolluting energy resources. Hydrogen is emerging as a natural choice as a more secure and cleaner energy carrier. Fuel cells can be used to produce clean energy from hydrogen, particularly for portable applications. Hydrogen can be produced f...

The riser reactor in a resid fluidised-bed catalytic cracking (resid-FCC) unit is simulated using a multigrain model of the catalyst in which the amorphous matrix as well as the embedded Y-zeolite crystals are porous and reactive. A seven-lump kinetic model is proposed to describe the reactions involved in resid-FCC. The steady-state mass and energ...

The oxidative steam reforming of ethanol (OSRE) and water-gas shift (WGS) reactions were studied in a microchannel reactor. For OSRE, the experiments were conducted at atmospheric pressure, with water to ethanol molar ratio of 3 or 6 and oxygen to ethanol molar ratio ranging from 0.5 to 1.5, over a temperature range of 350-550°C on Rh/CeO<sub align...

Microstructured monolith reactors washcoated with ZSM5 and La2O3-loaded ZSM5 (LaZSM5) were used for disproportionation of toluene for studying the effect of washcoat thickness on reactor productivity and yield of the commercially important p-xylene isomer. The toluene conversion and p-xylene yield in the ZSM5 washcoated monolith reactor was superio...

Pyrolysis of n-heptane was carried out in a tubular reactor, in presence of three initiators viz., di-tert-butyl peroxide (DTBP), diisopropylamine (DIPA) and triethylamine (TEA), in the temperature range of 773–953 K, pressure range of 0.1–2.93 MPa and mole ratio of 0.005–0.03 mole initiator per mole of n-heptane. Influence of temperature, pressure...

ZSM5 washcoated monoliths with zeolite loading ranging from 10 to 60 wt % were prepared, characterized, and examined for disproportionation of toluene. Toluene conversion increased with temperature and W/FAo but decreased with washcoat thickness. The selectivity of the most desirable isomer (p-xylene) increased with a decrease in temperature, W/FAo...

The kinetics of steam reforming of ethanol (SRE) was determined at atmospheric pressure in the temperature range of 450–550 °C over 2% Rh/20% CeO2/Al2O3 in a microchannel reactor. The product distribution could be explained by a reaction scheme consisting of four reactions: reaction of steam with ethanol, decomposition of ethanol, methane steam ref...

Abstract Monoliths washcoated with ZSM5 and metal oxide (MgO, CaO, La2O3 or CeO2) modified ZSM5 were prepared, characterized and studied for toluene disproportionation. An improvement in the yield of the desired p-xylene isomer was obtained by using monoliths coated with metal oxide-modified ZSM5. The enhancement in p-xylene yield depended on the t...

Steam reforming of ethanol was studied over Rh/CeO2/Al2O3 catalysts in a micro-channel reactor. First, the catalyst support was deposited on to the metallic substrate by washcoating and then the CeO2 and active metal were sequentially impregnated. The catalysts were characterized by means of BET surface area, temperature programmed reduction, H2 ch...

Oxidative steam reforming of ethanol (OSRE) was studied over Rh/CeO2/Al2O3 catalysts in a micro-channel reactor. First, the catalyst support, Al2O3, was deposited on to the metallic substrate by washcoating and then the CeO2 and active metal were sequentially impregnated. The effect of support composition as well as active metal composition on oxid...

In the contemporary era of looming energy crunch, hydrogen fuel, obtained from ethanol, is a potentially strong contender as an energy carrier, based on a renewable source. Moreover, acknowledging the critical importance of distributed power devices and systems on one hand and the importance of microscale engineering on the other, we envisage devel...

The hydrogenation of alpha-methyl styrene on 0.5 wt% Pd/Al2O3 at 40 °C and atmospheric pressure was used to study the performance of monolithic catalyst with different washcoat loadings at low gas and low liquid superficial velocities. The superficial velocities of the gas and liquid were varied in the range of 0.31–1.25 cm/s and 0.075–0.3 cm/s, re...

Pd/Al2O3 monolithic catalyst of different washcoat thicknesses were prepared by two methods and tested for the activity of hydrogenation of {ogonek}-methyl styrene. These catalysts were prepared by two methods; either the palladium was impregnated on-alumina and this Pd/Al2O3 powder was used to prepare the slurry for washcoating (Cat 1) or -alumina...

A multigrain catalyst model is developed to describe the simultaneous multicomponent diffusion-cum-reaction taking place in a unifunctional multicomponent catalyst. In this, particles of the more active component are randomly dispersed in a less active near-spherical porous matrix. The catalyst macro-particle is assumed to consist of sub-layers of...

The effect of gas and liquid velocities on the rate of hydrogenation of α-methyl styrene (AMS) in a monolithic reactor has been investigated at different washcoat loadings. The catalyst used was 0.5 wt % Pd/Al2O3. To cover a wide range of velocities, reaction studies were conducted in multichannel as well as single-channel monolith blocks. The liqu...

Washcoating of alumina on cordierite monoliths has been studied with the objective of preparing monoliths with high loadings (>30 wt%). As the alumina loading increased, the competition between spreading and imbibition of the slurry in the monolith channels had a predominant influence on the loading that could be achieved. It was observed that, par...

In the present study, the effect of primer and slurry composition on the washcoat characteristics of γ-alumina on stainless steel substrate has been investigated. Washcoating was done following a two-step procedure: primer coating followed by slurry coating. Washcoat was characterized by SEM, adherence test and BET surface area measurement. For coa...

Pyrolysis of n-heptane was investigated in a tubular reactor in the temperature range of 793–953 K and pressure range of 0.1–2.93 MPa. At all conditions, the main products were methane, ethylene, ethane, propylene, 1-butene, 1-pentene and 1-hexene. With an increase in pressure, the selectivities of hydrogen, methane, ethylene and propylene decrease...

A procedure has been developed for estimating the wetting efficiency in a trickle-bed reactor by using the conversion data obtained for a reaction following nonlinear kinetics. For this purpose, the hydrogenation of α-methylstyrene on 0.5 wt % Pd/Al2O3 catalyst was studied in a batch slurry reactor (1.0−6.0 atm, 313−343 K), as well as in a trickle-...

In the contemporary era of energy crunch, hydrogen fuel, obtained from ethanol, is a potentially strong contender as an energy career based on a renewable source. Moreover, acknowledging the critical importance of distributed power devices and systems on one hand and the importance of microscale engineering on the other, we envisage developing an e...

Catalytic steam reforming of ethanol for hydrogen production in presence and absence of oxygen has been studied over Ni-CeO2-ZrO2 catalyst. The effect of oxygen addition and space time on conversion and product selectivities has been investigated in a down-flow tubular fixed bed reactor at atmospheric pressure with an ethanol/water molar ratio of 1...

Cordierite monoliths were washcoated with slurries of different zeolites (ZSM5, β zeolite, mordenite, and Zeolite Y) in order to establish the relationship between washcoat characteristics and the powder and slurry properties. To achieve this objective, initially, the zeolite particle size was reduced to 2–3 μm by wet ball milling, and during this...

In this study, the effect of tube diameter and type of distributor on the flow patterns during cocurrent, downward, gas - liquid flow has been investigated. The superficial velocities of the liquid phase (water) and the gas phase (air) were varied in the range of 0.01 - 0.25 m/s and 0.01 - 0.5 m/s, respectively. For this purpose, capillary tubes of...

Microchannels in stainless steel were fabricated by using solutions of various concentrations of FeCl3, HCl and HNO3 in water as etchants. This study shows that for obtaining smooth uniform channels on stainless steel substrates, an etchant consisting of FeCl3, HCl and HNO3 is necessary. An increase in the concentration of HCl in the etchant increa...

Steam reforming (SR) and oxidative steam reforming (OSR) of ethanol were investigated over undoped and Cu, Co and Ca doped Ni/CeO2–ZrO2 catalyst in the temperature range of 400–650 °C. The nickel loading was kept fixed at 30 wt.% and the loading of Cu and Co was varied from 2 to 10 wt% whereas the Ca loading was varied from 5 to 15 wt.%. The cataly...

The effect of addition of chromium and nickel oxides on the physicochemical properties and performance of V2O5/ZrO2 catalysts was studied for the oxidative dehydrogenation of propane. Addition of chromium oxide increased, whereas addition of nickel oxide lowered the activity. Selectivity for propene was lower for the doped catalysts. The selectivit...

Concentrated black liquor was pyrolysed in a semi-batch reactor in an inert atmosphere of nitrogen at 873–993 K. The effects of temperature and reaction time on the gas yields and compositions were studied. The main components of the gaseous product were hydrogen, methane, carbon monoxide, carbon dioxide and sulphur-containing gases. The percentage...

Steam reforming (SR) of ethanol for hydrogen production was investigated over Ni/Ce1-xZrxO2 (x = 0, 0.26, 0.59, 0.84 and 1) catalyst prepared by co-precipitation and incipient wetness impregnation technique. The effect of support composition as well as metal loading on SR reaction was studied in a downflow tubular fixed bed reactor at atmospheric p...

The main reaction and deactivation kinetics of cyclohexane dehydrogenation in the presence of hydrogen has been investigated at atmospheric pressure over a nickel kieselguhr catalyst in the temperature range 583–623 K. The rate of reaction for the fresh catalyst increased with increasing temperature, cyclohexane and hydrogen partial pressures where...

The product distribution and kinetics of thermal cracking of JP-10 (exo-tetrahydrodicyclopentadiene) were investigated in an annular tubular reactor at atmospheric pressure, in the temperature range of 903–968 K. No inerts were added with the feed. The major products were methane, ethylene, propylene, cyclopentene, cyclopentadiene, benzene and tolu...

The effect of calcium and potassium on the physiochemical properties and performance of V2O5/ZrO2 catalyst for oxidative dehydrogenation of propane was studied in the temperature range of 385–400 °C. The vanadia loading was kept constant at 5 VOx/nm2 and the atomic ratio A/V (A=Ca, K) was varied from 0.05 to 0.75. The vanadia surface structure was...

The performance of zirconia supported vanadia catalyst has been investigated for the oxidative dehydrogenation of propane. Vanadia loading was varied from 1.6 to 22.7 wt%, both below and well above monolayer coverage. The turnover frequency was highest for the catalyst with a vanadia surface density of 5 VOx /nm2. The effect of vanadia loading on t...

A method for the digestion of organophosphorus compounds and the determination of phosphorus in aqueous and organic phases, which are obtained on pyrolysis of naphtha, has been proposed. The method is based on the formation of molybdivanadophosphate (MVP) which exists as stable and true yellow solution. Sample oxidation (digestion) is achieved usin...

This study provides insights into the optimal operation of the fluidized-bed catalytic cracking unit (FCCU). A five-lump model is used to characterize the feed and the products. The model is tuned using industrial data. The elitist nondominated sorting genetic algorithm (NSGA-II) is used to solve a three-objective function optimization problem. The...

Steam pyrolysis of n-heptane has been studied over different calcium aluminates and potassium impregnated calcium aluminate in a fixed bed reactor at atmospheric pressure. Various calcium aluminate catalysts were prepared by changing the precursor salt for obtaining CaO, which was subsequently used with Al2O3 for catalyst preparation. Depending on...

Noncatalytic and catalytic pyrolysis of toluene has been studied at atmospheric pressure in the temperature range of 1043 to 1153 K using steam or nitrogen as the diluent. The catalyst used was potassium carbonate impregnated calcium aluminate. Compared to noncatalytic pyrolysis, the conversions were significantly higher in the presence of the cata...

Steam pyrolysis of methylcyclohexane has been studied over potassium carbonate impregnated calcium aluminate catalyst in a fixed bed reactor at atmospheric pressure in the temperature range of 973–1073 K. Compared to noncatalytic pyrolysis, the conversion was significantly higher but the hydrocarbon product selectivities were not affected in the pr...

The effectiveness of potassium promoted calcium aluminate to catalyze the steam pyrolysis of n-heptane has been investigated at 1023 K and atmospheric pressure. Various amounts of potassium were incorporated on calcium aluminate (12CaO7Al2O3) by three different methods. Compared to thermal pyrolysis, addition of the calcium aluminate catalyst (eit...

Steam pyrolysis of n-heptane has been studied over potassium carbonate impregnated calcium aluminate (12CaO−7Al2O3) catalyst in a fixed bed reactor at atmospheric pressure in the temperature range of 953−1023 K. Compared to noncatalytic pyrolysis, the conversion and product yields of methane, ethylene, and propylene were significantly higher in the...

Steam pyrolysis of methylcyclohexane has been investigated in a tubular reactor at atmospheric pressure in the temperature range 953-1073 K. Using non-linear regression, the overall decomposition was found to be approximately first-order with a pre-exponential factor and activation energy of 1.711011 s−1 and 209.0 kJ mol−1, respectively. The experi...

The fiber length distributions of carbon fibers grown on alumina substrates by the vapor phase decomposition of benzene have been measured at different lengthening times in the temperature range of 1283–1353 K and at two concentrations of benzene. The proportion of longer fibers increased with lengthening time. A two-parameter model has been used t...

The kinetics and product distribution during the pyrolysis of n-heptane have been investigated in the temperature range 953–1023 K at atmospheric pressure, with steam as the inert diluent. The overall n-heptane decomposition can be represented by a first-order reaction with a frequency factor of 6.02 × 1013s−1 and an activation energy of 250.7 kJ m...

Carbon fibers were grown on alumina substrates by vapor phase decomposition of benzene in the presence of hydrogen in a tubular reactor. The effect of lengthening duration and temperature on the average fiber length was studied at two different benzene concentrations (13.2 and 18.6 mol%). In the temperature range (1283–1353 K) investigated, the max...

A mechanistic model has been used to predict filament length distributions for vapor grown carbon fibers during the lengthening stage. Optimal values for the two parameters, α and Lt, in this model are obtained by curve-fitting one set of experimental results, giving excellent agreement. The model can easily be used to predict length distributions...

The effectiveness of benzyl diethyl phosphite as a coke inhibitor during naphtha pyrolysis was investigated in a tubular reactor at 1073 K and atmospheric pressure. Significant reduction in the coking rate was achieved by adding benzyl diethyl phosphite to the feed. The effect of toluene, methylcyclohexane, l-octene and carbon disulfide on the rate...

Steam pyrolysis of naphtha has been studied over potassium carbonate impregnated calcium aluminate (12CaO-7Al2O3) catalysts in a fixed-bed reactor at atmospheric pressure in the temperature range of 1033-1093 K. The K2CO3 loading on the catalyst was varied from 0 to 8.8 wt %. Incorporation of K2CO3 in the catalyst significantly reduced the coke dep...

A kinetic scheme has been proposed as a feasible model to explain the lengthening step in vapor grown carbon fibers from the pyrolysis of hydrocarbons. The two-parameter model assumes that the filaments lengthen by the reaction of a pyrolysis product with the growing filaments, and that the growth process ceases when the catalyst particle attached...

This paper reports that significant reduction in the rate of coke formation during naphtha pyrolysis was achieved by adding benzyl diethyl phosphite or triphenylphosphine sulfide to the feed. Although the yield of carbon oxides was reduced, there was no effect of these additives on the hydrocarbon yields. Addition of these organophosphorus compound...

Rates of coke formation during steam pyrolysis of naphtha have been investigated in a jet-stirred reactor both for sodium silicate coated and uncoated Inconel 600 surfaces in the temperature range of 1078–1108 K. Coke formation rates were significantly reduced on sodium silicate coated plates due to the passivation of the metal surface. However, th...

Steam pyrolysis of naphtha has been studied over a calcium aluminate (12CaO-7Al2O3) catalyst in a fixed bed reactor at atmospheric pressure in the temperature range 973-1123 K. Conversion of naphtha increased appreciably in the presence of the catalyst, reducing the temperature required for a given conversion by approximately 50 K. Compared to ther...

A three parameter model has been developed for a two-stage vacuum gas oil hydrocracker unit. The feed and the products were lumped into 23 pseudocomponents, each characterized by its boiling range and specific gravity. The model assumes that each pseudocomponent can only form lighter products by a pseudohomogeneous first order reaction. The model p...

In this article the technology, kinetics, chemistry and reactor modelling of hydrocracking have been reviewed. While it is intended to provide a general overview of the recent advances in this process, greater emphasis has been given to technology and reactor modelling because of their industrial importance. Over ninety references have been cited.

The effectiveness of triphenyl phosphite as a coke inhibitor during naphtha pyrolysis has been investigated. Pyrolysis runs were conducted in a jet-stirred reactor at atmospheric pressure in the temperature range 1088-1108 K. Addition of triphenyl phosphite significantly reduced the coke formation without affecting the product yields. Used in the s...

Waste lubricating oil was re-refined by the conventional acid clay treating process. The effect of various operating parameters on the properties and yield of re-refined oil were investigated. Both for acid and clay treating steps, the contact time, temperature and concentration were varied and the optimum ranges determined for these variables. For...

Pyrolysis of naphtha in uniform diameter and swaged reactors has been modeled. Pyrolysis and coking models available for naphtha cracking were used to calculate the reactor profiles of pressure, process gas temperature, tube metal temperature, conversion and the product yields. For the swaged coil, not only was the inlet pressure and maximum tube w...

The reduction in the rate of coke formation during naphtha pyrolysis due to the injection of triethyl phosphite has been investigated in a jet-stirred reactor at atmospheric pressure in the temperature range of 1088-1108 K. Coke formation was significantly reduced in the presence of the additive. The data are consistent with the formation of a meta...

The effect of run time, temperature, conversion and inlet steam-to-naphtha ratio on the rate of coke deposition during naphtha pyrolysis in an annular tubular reactor has been investigated. Rates of coke deposition increased with increasing temperature, conversion and inlet naphtha partial pressure. Pyrolysis and coking models available for naphtha...

Rates of coke formation during steam cracking of n-hexane have been investigated in a jet-stirred reactor both for potassium carbonate coated and uncoated 304 stainless steel surfaces in the temperature range of 993-1113 K. Rates of coke deposition were measured by periodically weighing a small cylinder suspended into the center of the reactor. Cok...

The effect of temperature, space time and the inlet partial pressure of n-hexane on rates of coke deposition in hexane pyrolysis have been investigated in a tubular reactor. The amount of coke deposited was measured by burning the coke with air, converting the carbon monoxide to carbon dioxide and measuring the resulting amounts of water vapor and...

Black liquor solids of -30+60-, -60+80-, and -80+150-mesh size were pyrolyzed in a fixed-bed reactor in an inert atmosphere of nitrogen at 863-1013 K and atmospheric pressure. The effect of reaction time, temperature, and feed particle size on the product yields and the composition of product gases was investigated. The main components of the produ...

The variation in the activity and performance factors with Thiele modulus, poisoning level and ratio of inside-to-outside catalyst diameter for hollow cylindrical pellets undergoing pore mouth poisoning has been presented. It has been shown that only for strong pore diffusion limitations is the performance of hollow pellets better than that of soli...

Pyrolysis of n-hexane was studied in a jet-stirred mixed reactor in the temperature range of 993-1083 The kinetics of the overall pyrolysis, as well as the coke formation, was investigated. The overall pyrolysis was essentially first order, and the major products were ethylene, methane, propylene, and hydrogen. The effect of temperature, conversion...

The effect of run time, surface area, reaction temperature and inlet naphtha partial pressure on the rate of coke formation during naphtha pyrolysis has been investigated in a jet-stirred reactor. The pyrolysis products could be predicted by a model developed earlier for naphtha pyrolysis. Various simplified models for the coke formation involving...

This note discusses the effect of concentration-independent deactivation on the effectiveness factor of bidispersed catalysts and analyzes the combined effect of diffusion and deactivation on the performance of a plug-flow reactor utilizing a bidispersed catalyst. The analyses of Levenspiel for diffusion-free catalysts and Krishnaswamy and of Kittr...

Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/25600/1/0000147.pdf

The effect of temperature, inlet steam to naphtha ratio, and space time on the yields of the major products in naphtha pyrolysis has been investigated. The temperature, steam/naphtha, and space time were varied in the range 993-1073 K, 0.71-1.43 kg/kg, and 0.024-0.76 s, respectively. The overall naphtha decomposition could be represented by a first...

An optimal time-temperature policy to maximize the cumulative yield of the desired product has been developed for a first-order consecutive reaction, subject to concentration-dependent catalyst deactivation conducted in a continuous stirred tank reactor. A graphical methodology utilizing Pontryagin's Minimum Principle has been used. In general, the...

Municipal solid waste fraction of average particle size 0.42 mm and a uniformity coefficient of 1.65 was partially oxidized in a continuous reactor in the temperature range of 973 to 1123 K and the variation in gas yields, composition and product heating values with temperature and oxygen/feed ratio was investigated. The main components of the prod...

In the hydrolytic polymerization of ϵ-caprolactam, the ring opening of the monomer is much slower than the polyaddition reaction. Hence, the mixing of aminocaproic acid to the feed results in a faster conversion of the monomer. Industrially, this fact is exploited by using a recycle stream. An isothermal plug flow reactor (PFR) with a recycle is si...

The second stage of batch poly(ethylene terephthalate) (PET) reactor with bis(2-hydroxyethyl) terephthalate (BHET) as the feed has been simulated. In this stage, the overall polymerization is not diffusion limited and is known to be a complex reaction. In this work it has been assumed to consist of polycondensation, reaction with monofunctional com...

The concept of modelling the effect of crystal size distribution on sorption in molecular sieves by assuming the sorption to take place on a progressively swelling crystal is applied to sorption with various bulk concentration profiles. The radius of the swelling crystal is related to the fractional approach to equilibrium, which has been defined i...

A model is developed to simulate non-isothermal packed-bed sorption on uniform as well as nonuniform zeolite crystals. Intracrystalline diffusion is assumed to be the controlling resistance. Temperature dependence of adsorption constant and diffusivity are taken into account. The swelling crystal model is used to incorporate size distribution effec...

The feasibility of using steam as a desorbent for n-paraffins adsorbed on Linde Molecular Sieve 5-A was investigated. The feedstock was kerosene obtained from Gujrat Refinery and experiments were conducted at two different temperatures for a fixed feed rate. Desorption with steam was carried out repeatedly for a number of cycles without intermediat...

The effect of zeolite crystal size distribution on sorption has been studied for a packed bed subjected to a pulse input. The swelling crystal approach proposed recently has been used lo incorporate the effect of size distribution. The effluent concentration pulse and its moments show significant dependence on size distribution. Use of conventional...

Bovine waste fractions of particle sizes > 30 < 44, > 44 < 72 and > 72 < 100 (Tyler standard series) were pyrolysed in a fluidized bed reactor at 873–1073 K and the variations in gas yields, composition and product heating values investigated. Gas yields increased with temperature and ranged from 0.5 to 0.65 N m3 kg−1 of as received waste. The main...

Liquid-phase adsorption studies of binary and ternary systems of n-paraffins (C5-C8) on LMS-5A were conducted at 6, 18, 30, and 42 °C. Equilibrium adsorption was found to be essentially independent of temperature, for all the binary systems studied, except those containing pentane at 30 °C where a decrease in adsorption was observed. A two-paramete...

A model is proposed to take into account the non-linearity of equilibrium isotherm, concentration dependence of diffusivity and zeolite crystal size distribution while calculating the sorption curve for a single component adsorption on molecular sieves. The effect of size distribution is modelled by assuming the adsorption to take place on a progre...

A model has been proposed to predict breakthrough curves for packed bed adsorption columns. Adsorbent particle size distribution has been taken into account. Compared to uniform crystals, the breakthrough for non-uniform crystals occurred after a longer time interval and the delay increased as the size distribution became broader. The dynamic capac...

Liquid-phase adsorption of n-pentane, n-hexane, n-heptane, and n-octane from (nonadsorbed) benzene on Linde 5A molecular sieve was carried out to study the effect of temperature and concentration on equilibrium loading. On a mole basis, the adsorption was higher for lower molecular weight paraffins. The effect of temperature on equilibrium loading...

High-speed liquid chromatographic separation of chloroaniline and toluidine isomers was accomplished in six minutes using cadmium-impregnated silica gel. Efficiency and capacity factors were found to depend on the amount of cadmium impregnated. The increase in retention time and selectivity in cadmium-impregnated columns was related to the basicity...