Laboratory-scale Unit Research Articles

Monitoring the progress of catalytic cracking for model compounds in the mid-infrared (MIR) 3200–2800 cm−1 range

Hydrocarbon species concentrations in the gas phase are of critical importance to elucidate catalytic cracking kinetics and riser/downer fluid dynamics. In this respect, Mid-Infrared (MIR) spectroscopy provides a singular approach to monitor chemical species conversions at various reaction times. In the MIR, the Absorption Cross Section Coefficients and Integrated Absorption Band Intensities can be related to the number of C-H bonds present in the different chemical species. The proposed methodology is based on a Group Contribution Method (GCM), which accounts for the additive contribution of molecular functionalities related to the CH bonds present in hydrocarbons. This allows absorption spectra predictions in 3200–2800 cm−1 region. This Group Contribution Method can be applied in conjunction with a helium-neon (HeNe) laser, with a 2949.85 cm−1 wavenumber (3.39 µm wavelength). The technique is validated using both 1-hexene and 1,3,5-TIPB catalytic cracking data. The importance of the proposed method is shown in the context of using a CREC Riser Simulator, a mini-fluidized laboratory scale unit invented at CREC-UWO (de Lasa, 1991). Hydrocarbon species are MIR monitored in the outer CREC Riser Simulator annulus. The data obtained can be used to extrapolate gas phase hydrocarbon conversions and fluid molar densities in risers and downers. This information can be also used to accurately predict fluid dynamics in FCC catalytic cracking units.

Efficient treatment of dairy processing wastewater in a laboratory scale Intermittently Aerated Sequencing Batch Reactor (IASBR).

This Research Communication describes an investigation into the viability of an Intermittently Aerated Sequencing Batch Reactor (IASBR) for the treatment of dairy processing wastewater at laboratory-scale. A number of operational parameters have been varied and the effect has been monitored in order to determine optimal conditions for maximising removal efficiencies. These operational parameters include Hydraulic Retention Time (HRT), Solids Retention Time (SRT), aeration rate and cycle length. Real dairy processing wastewater and synthetic wastewater have been treated using three laboratory-scale IASBR units in a temperature controlled room. When the operational conditions were established, the units were seeded using sludge from a municipal wastewater treatment plant for the first experiment, and sludge from a dairy processing factory for the second and third experiment. In experiment three, the reactors were fed on real wastewater from the wastewater treatment plant at this dairy processing factory. These laboratory-scale systems will be used to demonstrate over time that the IASBR system is a consistent, viable option for treatment of dairy processing wastewater in this sector. In this study, the capacity of a biological system to remove both nitrogen and phosphorus within one reactor will be demonstrated. The initial operational parameters for a pilot-scale IASBR system will be derived from the results of the study.

Investigation of lab-scale horizontal subsurface flow constructed wetlands treating industrial cork boiling wastewater

The feasibility and treatment efficiency of horizontal subsurface flow constructed wetlands (HSFCW) was assessed for the first time for cork boiling wastewater (CBW) through laboratory experiments. CBW is known for its high content of phenolic compounds, complex composition of biorecalcitrant and toxic nature. Two lab-scale units, one planted with Phragmites australis (CWP) and one unplanted (CWC), were used to evaluate the removals of COD, BOD, total phenolic compounds (TPh) and decolourization over a 2.5-years monitoring period under Mediterranean climatic conditions. Seven organic and hydraulic loading rates ranging from 2.6 to 11.5 g COD/m2/d and 5.7–9.1 L/m2/d were tested under average hydraulic retention time (HRT) of 5 ± 1 days required due to the CWB limited biodegradability (i.e., BOD5/COD of 0.19). Average removals of the CWP exceeded those of the CWC and reached 74.6%, 91.7% and 69.1% for COD, BOD5 and TPh, respectively, with respective mass removals rates up to 7.0, 1.7 and 0.5 (in g/m2/d). Decolourization was limited to 35%, since it mainly depends on physical processes rather than biodegradation. CBW concentration of nine phenolic compounds ranged from 1.2 to 38.4 mg/L (for the syringic and ellagic acids, respectively) in the raw CBW, with respective removals in the CWP unit ranging from 41.8 to 76.3%, higher than those in the control unit. Despite CBW high concentration of TPhs (average of 116.3 mg/L), the HSFCW reached organic load removals higher than those of conventional biological treatment methods.

Extraction and modeling of flaxseed (Linnum usitatissimum) oil using subcritical propane

This study aimed at investigating flaxseed (Linnum usitatissimum) oil extraction using subcritical propane. Extractions were performed in a laboratory scale unit at temperature (20–60 °C) and pressure (80–120 bar) experimental conditions. Subcritical extraction process kinetic aspects evaluation was performed using four mathematical models found in the literature. The subcritical propane process successfully extracted Omega 3-6-9 fatty acids presenting good yielding in the experimental conditions studied. Physical characterization for commercial and subcritical propane extraction oils presented 1.477 and 1.473 refractive indexes at 40 °C, respectively. The oil extracted using subcritical propane presented free fatty acid contents lower than commercial oil (0.95% wt vs 1.37% wt). The adjusted parameters models presented good fitting with the experimental data under the investigated conditions.

Hybrid Processes for Extraction–separation of Tocopherols from Crude Palm Oil

The aim of this study was to evaluate the hybrid processes for extraction and separation of tocopherols from crude palm oil. The saponification method was used to extract crude palm oil under various concentrations of alcoholic KOH in the range of 10–60% w/v in a lab scale unit. The experiments were conducted at a temperature and saponification time in the range of 60–80°C and 20–40 min respectively. The performance and efficiency of ultrafiltration were investigated by filtering a fraction of unsponifiables. The results showed that the optimum condition of saponification was 10% alcoholic KOH with the minimum loss of α–tocopherol of around 19%. A lab scale filtration unit with a hydrophobic sheet membrane was operated under a frontal filtration mode at room temperature. The results pointed out that ultrafiltration could remove most of the residual triglycerides and phospholipids contained in unsponifiables at a TMP of 0.25–1.0 bars. The removal of up to 70% of triglycerides and phospholipids was reached when the mixture was ultrafiltered. In addition, these hydride processes present a one of the great option for α–tocopherol purification losing about 5% of yield.

Comparison of Performance of an Intermittent Aeration Membrane Bioreactor and a Conventional Activated–sludge System in the Treatment of Palm Oil Mill Effluent

The main objective was to compare the performances and the removal efficiencies of two biological treatment systems, a submerged membrane bioreactor (SMBR) and a simultaneous activated sludge (AS), for treating Palm Oil Mill Effluent (POME). Two lab scale units of SMBR and AS with a working volume of 24 L were operated under favorable biological conditions and minimized membrane fouling intensity. To achieve both carbonaceous and nitrogen removal, the cyclic air intermittent and dissolved oxygen control were performed into SMBR and AS with the influent flow rate about 16 L/d respectively. In terms of organic removal and membrane performance, the SMBR showed good removal efficiency to treat high strength wastewater with organic loading variation of POME. The average removal rates of TCOD, BOD, Turbidity, Color, Oil and Grease, NH3–N, TKN were 69±2, 76±2, 100±1, 37±21, 92±6, 67±4 and 75±10% respectively. Results pointed out the benefit of membranes retained totally the active compositions of biomass in each stage of development. The AS showed the limitation of sedimentation phase for sludge and oil separation. The characteristics of sludge in SMBR showed healthy floc formations and good settling after 240 h. The concentrations of COD and BOD in permeate were around 870±53 and 37±13 mg/L.

Preliminary Study of Hospital Wastewater Treatment with a Submerged Membrane Bioreactor (SMBR): Case Study of Songklanagarind Hospital – Thailand

The objective of this research was to study hospital wastewater treatment using a submerged membrane bioreactor (SMBR). The lab scale unit of SMBR with a working volume of 20 liters was operated at a hydraulic retention time of 0.416 day and 0.208 day at F/M ratio of 0.18 day–1 and 0.29 day–1. The operating conditions were set up to provide good biological treatment without sludge extraction, and two different permeate flux values were studied. The performance of membrane was studied by monitoring the variation of transmenbrane pressure (TMP) during filtration runs. The efficiency of MBR was investigated according to the daily measurements of pH, dissolved oxygen and temperature. The COD, BOD5, NH4+–N, TKN, color, turbidity, SS and Escherichia coli (E.coli) in influent and effluent were analyzed. Membrane fouling intensity occurred slowly when the system operated with flux at 10 L/h/m2 and 20 L/h/m2, which induced high TMP at the initial period of filtration. The fouling rate was at about 0.3022 mbar/day for the permeation of flux at 10 L /h/m2. The fouling rate still remained at 0.2774 mbar/day for 20 L/h/m2. The results showed the great effect of membrane use for total biomass retention and the removal rate of COD, BOD5 and E.coli were over 90%. The characteristics of sludge in SMBR showed healthy floc formations with good settling. Although the ratio of MLVSS/MLSS was lower than the normal range (about 0.2), it was found that the average values of COD and NH4+–N in permeate were lower than 2–80 mg/L and 0.05–6.755 mg/L while the value of turbidity was also less than 3 NTU.

Ni-ferrite with structural stability for solar thermochemical H2O/CO2 splitting

NiFe2O4, which has been proven as one of the best thus far materials for the Thermochemical two-step H2O- and CO2-splitting processes, has limited use due to extended loss of its surface area after several redox reaction cycles at high temperature. In this work, porous NiFe2O4 materials with improved thermal stability at temperatures up to 1450 °C are synthesized, using a conventional ceramic processing route. In order to increase the porosity and the thermal stability of the prepared materials, ZrO2 as well as sacrificial templates, polyethylene glycol and carbon black, are added. The highest thermal stability and conservation of porosity are obtained with 20% wt carbon black and zirconia content 10–30% wt. The most promising samples are tested at a laboratory scale unit, where they are subjected to multiple redox cycles. It is proven that the samples with the highest porosity and optimum pore size distribution have the highest capability to reversibly deliver and pick up their lattice oxygen.

Dimensional Analysis of an Electromembrane Reactor for Recycling and Resource Recovery of Flue Gas Desulfurization Residuals

Abstract Flue gas desulfurization (FGD) technologies have been applied worldwide in power plants to achieve regulatory standards for the emission of SO2. However, commercial methods in practice require increased costs for disposal of the FGD residuals or by-products. An electromembrane reactor for recycling and resource recovery of FGD residuals was proposed in this study. On the basis of previous work, a mathematical model was developed to describe the mass balance of proposed electromembrane reactor by originally introducing the dimensionless groups, which can help in understanding the mechanism of electrochemical processes and in removing barriers against scaling up a lab-scale chemical unit to a commercial size. On the other hand, results of numerical simulation agreed well with the experimental data, which verified the capability of the developed model for mass transfer. With the help of dimensionless groups, analysis of the model revealed that current density, flow pattern, and initial concentration...

A STUDY OF UNCOATED AND COATED UREA CRYSTALS DISSOLUTION IN STIRRED VESSEL

An immersing and spray coating process has been developed for the continous production of tapioca starch and silica coated urea. The coating thicness and quality of coated urea was produced in a laboratory-scale unit. The dissolution rates of urea uncoated and coated urea crystals were studied in a stirred vessel. Coated urea crystals genarally shows low dissolution rates compared to uncoated for all coating materials. The effect of coating was best with tapoca starch and silica combination baked at 70oC. This cating material of tapioca starch coating urea the dissolution time was in the range of 300 to 360 second mass transfer coefficient in the range of between 3.63 x 10-6 to 2.91 x 10-3 cm 2/s. And for the silica coated urea coating material, the dissolution time was in the range of 300 to 380 second. mass coefficient in the ranger of 1.65 x 10-2 to 3.30 x 10-2 cm/s.and diffusion coefficient in the ranger of 3.57 x 10-6 to 3.30 x30 x 10-3 cm 2/s. The dissolution rangers from about 87% for a product containing 10.5 % tapioca starch to the dissolution range of about 85% for a product containing 9.5% silicaKeywords : urea crystals, Coating, dissolution, stirred vessel

Evaluation of Pressure Filtration of Coal Refuse Slurry: A Fractional Factorial Design Approach

ABSTRACTPressure filtration provides an opportunity for dewatering coal refuse sufficiently to reduce or possibly eliminate the need for a slurry impoundment. In this study, pressure filtration was performed in a lab-scale unit to evaluate the dewatering nature of coal refuse slurry, which was obtained from a coal preparation facility. Evaluation of the process was performed using a fractional factorial design with cake moisture as the response and pressure, pH, and solids concentration as the variables of interest. Results indicated a decrease in cake moisture with increase in solids concentration and pressure, and an increase in cake moisture with pH. With pH playing a significant role in dewatering coal refuse slurry, zeta potential measurements were performed at different pH values to confirm the likeliness of agglomeration at lower pH. Filtrate flux values from the current test matrix were compared with the flux values of a bench-scale pressure filter, and a logarithmic relationship between the filtrate fluxes of the two units was developed. Results also indicated that for lower values of filtrate flux, the flux per discharge port remained constant during the scale-up from bench-scale to lab-scale units.

Separation and recovery of lignin from hydrolysates of lignocellulose with a polymeric adsorbent

Abstract Separation and recovery of lignin from monosaccharide rich hydrolysates of lignocellulose by adsorption was investigated. Six polymeric adsorbents were compared by batch equilibrium experiments. XAD-16N was found to be the most efficient. Use of XAD-16N was studied in more detail in a column. A good separation efficiency could be obtained: with 95% monosaccharide recovery yield limit, the lignin removal level was 80%. Organic acids and furans were not adsorbed on XAD-16N. Practically all of the adsorbed lignin could be recovered efficiently with 50 wt.% aqueous ethanol solution. The lignin fraction had 99% purity with respect the other solutes in the hydrolysates. Applicability of the process on large scale was demonstrated successfully by scaling up the process using data obtained with a laboratory scale unit (scale-up factor: 420). A 76% lignin removal (target: 70%) was achieved with higher than 95% monosaccharide recovery yield (target: 95%).

Biofiltration of xylene using wood charcoal as the biofilter media under transient and high loading conditions

The main objective of this study was to evaluate the performance of wood charcoal as biofilter media under transient and high loading condition. Biofiltration of xylene was investigated for 150days in a laboratory scale unit packed with wood charcoal and inoculated with mixed microbial culture at the xylene loading rates ranged from 12 to 553gm−3h−1. The kinetic analysis of the xylene revealed absence of substrate inhibition and possibility of achieving higher elimination under optimum condition. The pH, temperature, pressure drop and CO2 production rate were regularly monitored during the experiments. Throughout experimental period, the removal efficiency (RE) was found to be in the range of 65–98.7% and the maximum elimination capacity (EC) was 405.7gm−3h−1. Molecular characterization results show Bacillus sp. as dominating microbial group in the biofilm.

Thermoliquefaction of palm oil fiber (Elaeis sp.) using supercritical ethanol

Thermoliquefaction of palm oil fiber was investigated using supercritical ethanol as solvent. A semi-continuous laboratory scale unit was developed to investigate the effects of temperature (300–500°C), heating rate (10–30°C.min−1) and cracking time (10–30min) on the conversion of biomass in bio-oil. The main advantage of the proposed process is that a pure solvent is pumping through the reactor that contains the biomass, dispensing the use of biomass slurries. The yield of bio-oil ranged from 56% to 84%, depending on the experimental conditions. It was observed that an increase in working temperature led to an increase in the bio-oil production. Cracking time and heating rate variation had not shown a considerable effect on the conversion of biomass. The chemical profiles of bio-oil determined by GC/MS, indicate that at low temperature mainly sugar derivatives are produced, while at higher temperatures alcohols and phenolic are the majority compounds of the bio-oil.

INDUSTRIAL EXTRACTION PILOT PLANT FOR STRIPPING H<sub>2</sub>S GAS FROM BLACK SEA WATER

The results from the laboratory-scale extraction pilot plant unit for the separation of H 2 S from Black Sea water lead us to build a novel industrial extraction pilot plant to concentrate H 2 S from 10 ppm to above 10000 ppm. The processing of 10 9 m 3 of water containing 10 ppm will produce 0.833 tons of hydrogen and therefore a technology for extraction and concentration of H 2 S is essential. The conceptual pilot plant proposed in this paper is in principle similar to the laboratory pilot plant developed in the University of Duhok, Iraq, and it could work to pump water directly from Black Sea. It contains a screen with electrical heater to fix the temperature of stripping, a water chiller at the top to separate any water droplet or vapor. The research on industrial pilot plant has shown that, this unit could operate both on and underneath the surface of the sea.

Preparation and Characterization of Borosilicate Glass Waste Form for Immobilization of HLW from WWER Spent Nuclear Fuel Reprocessing

ABSTRACTBorosilicate glassy materials for immobilization of HLW from Russian WWER (PWR) spent nuclear fuel reprocessing were designed, synthesized in a resistive furnace, and characterized by XRD, SEM/EDS, and FTIR spectroscopy. Chemical durability was determined by PCT-A procedure and compared to EPA glass and reference data. The glasses with 20 and 25 wt.% waste loading were found to be X-ray amorphous, homogeneous and chemically durable. Glass network formally had a relatively low degree of connectedness that was increased due to embedding of different structural groups thus improving chemical durability. Boron is present primarily in trigonal oxygen coordination. The glasses with 40-45 wt.% waste loading contained minor britholite phase concentrating rare earth elements and as expected trivalent actinides. Glassy product with up to 30 wt.% waste loading was also produced by cold crucible inductive melting at the IPCE RAS lab-scale unit equipped with 56 mm inner diameter copper cold crucible and energized from a 10 kW/5.28 MHz generator. The product was composed of vitreous phase and minor britholite with average composition K0.39Sr1.99Fe0.16Nd5.50Si7.96O26.60.

Low-temperature H2S removal for solid oxide fuel cell application with metal oxide adsorbents

The desulfurization of biogas is essential for the successful operation of solid oxide fuel cells. H2S is one of the main components in biogas. In order to feed a solid oxide fuel cell, the contaminated gas has to be reduced to a certain degree. In this work, different parameters onto the desulfurization performance of commercially available desulfurization adsorbents were investigated. The experiments were carried out using a custom made lab-scale unit. Synthetic biogas was passed through the sorbent bed and the outlet H2S concentration was measured. Experimental runs in a fixed bed reactor were conducted to monitor H2S removal efficiency of a zinc oxide adsorbent, an adsorbent based on a mixture of manganese and copper oxide and a zeolite adsorbent. H2S removal efficiency was monitored under various operating conditions such as different temperatures, space velocities and inlet concentrations. This work provides useful data for adsorption tower design and process optimization.

Conceptual Approach in Multi-Objective Optimization of Packed Bed Membrane Reactor for Ethylene Epoxidation Using Real-coded Non-Dominating Sorting Genetic Algorithm NSGA-II

Abstract An isothermal plug flow reactor model with extended Fick diffusion model for transport through the porous membrane is utilized for simulation of ethylene oxide formation in a packed bed membrane reactor (PBMR). The model was verified and validated using published experimental data from an existing lab-scale unit. Sensitivity analysis was performed to determine robustness of the model. A conceptual approach on operation and design stage multi-objective optimization study is discussed. Real-coded NSGA-II is used and effect of its parameters on optimization of reactor performance is also studied. The results of three two-objective operation-stage (with 4 decision variables) and one two-objective design-stage (with 6 decision variables) optimization case studies are presented. Good convergence to a Pareto optimal solution is achieved for all cases. Significant improvement over current experimental operation is observed in terms of increase in conversion of ethylene, selectivity to ethylene oxide and ethylene oxide product flow rate.

Numerical Modeling of an Air-Based Density Separator

ABSTRACTThe modern air-based density separator achieves density-based separation for particle sizes greater than 6 mm. Parametric studies, conducted with a modified laboratory-scale unit, operating at an optimal feed rate of 200 kg/hr to upgrade low-rank coal, have demonstrated the applicability to clean finer size fractions up to 1 mm. However, there is a lack of fundamental understanding of the separation process that can be provided utilizing numerical modeling techniques. The separation process was numerically modeled using K-Epsilon and RSM turbulence formulations and validated using experimental dataset. The results prove that the effect of fine coal vortices forming around the riffles act as a transport mechanism for higher density particle movement across the table deck resulting in 43% displacement of the high-density particles to the product side. The velocity and vector plots show high local variances of air speeds and pressure near the feed end and an increase in feed rate results in a drop in the deshaling capability of the table.

Extraction of inflorescences of Musa paradisiaca L. using supercritical CO2 and compressed propane

This work aimed to investigate the extraction of inflorescences of Musa paradisiaca L. using supercritical CO2 and compressed propane as solvents. The extractions were performed in a laboratory scale unit at temperature and pressure range of 313.15–353.15K and 15–25MPa for carbon dioxide and 308.15–338.15K and 3–10MPa for propane extractions, respectively. A 22 factorial experimental design with three replicates at central point was adopted to organize the data collection. The highest extraction yields were 3.60wt% using scCO2 at 313.15K and 25MPa and 3.14wt% with compressed propane at 338.15K and 10MPa. The overall extraction curves were modeled using a model based on the BET theory of adsorption. The kinetic model allowed correlating the different conditions of extraction with both scCO2 and compressed propane. The pressure of scCO2 presented a positive effect on the extraction yield of M. paradisiaca L. while temperature presented a negative effect. On the other hand, the increase of temperature allowed higher extraction yields of M. paradisiaca L. when propane was used. The most volatile fraction from the scCO2 extracts were composed by lupenone, methyl 2-hydroxy-2-(3-nitrophenyl)-2-(4-nitrophenyl)-acetate, pentacosane, 3,6,9-nonacosatriene, 10-hentriacontene and, 7,23-dimethyltritriacontane while for compressed propane extracts lupenone and 7,23-dimethyltritriacontane were the major constituents.