Solar Compound Parabolic Collector Research Articles

Photocatalytic hydrogen production from water-methanol and -glycerol mixtures using Pd/TiO2(-WO3) catalysts and validation in a solar pilot plant

This paper is focused on the photocatalytic hydrogen production on Pd/TiO2(-WO3) catalysts from water-methanol and water-glycerol mixtures under UVA and solar irradiation. The photodeposition method for Pd was studied varying conditions such as Pd amount, catalyst concentration and methanol concentration. The catalysts were tested at lab scale under simulated solar light and UVA radiation and also at large scale (25 L) under solar energy using a pilot-scale solar Compound Parabolic Collector (CPC). The catalysts characterization was performed by means of ICP-OES, N2 adsorption–desorption isotherms, XRD, HR-TEM, XPS and DR–UV–Vis spectroscopy. Hydrogen evolution was monitored by on-line gas chromatography.From results it was found the Pd photodeposition method plays a key role to increase the hydrogen evolution, affecting parameters like the Pd amount deposited, the Pd nanoparticles size and dispersion. The highest quantum efficiency (ϕ) obtained in this study was 11.8% and 41.2% under simulated solar and UVA irradiation, respectively, using Pd(0.24 wt%)/P25 in an aqueous solution of methanol (50 vol%). In the pilot-scale solar CPC, for Pd(0.24 wt%)//P25 catalysts in 5 vol% of methanol or glycerol as sacrificial agents, the quantum yield were 2.1 and 2.2%, respectively. When the concentration of the sacrificial agents decreased to 0.37 vol%, the quantum yields were 1.3 and 2.4% for methanol and glycerol, respectively. Compared to literature, the low noble metal content of these catalysts (0.25 wt%) seems to be a competitive factor considering their high price.

P-060. adverse effects of the use of magnesium sulfate in a patient with preeclampsia

This paper is focused on the photocatalytic hydrogen production on Pd/TiO2(-WO3) catalysts from water-methanol and water-glycerol mixtures under UVA and solar irradiation. The photodeposition method for Pd was studied varying conditions such as Pd amount, catalyst concentration and methanol concentration. The catalysts were tested at lab scale under simulated solar light and UVA radiation and also at large scale (25 L) under solar energy using a pilot-scale solar Compound Parabolic Collector (CPC). The catalysts characterization was performed by means of ICP-OES, N2 adsorption–desorption isotherms, XRD, HR-TEM, XPS and DR–UV–Vis spectroscopy. Hydrogen evolution was monitored by on-line gas chromatography.From results it was found the Pd photodeposition method plays a key role to increase the hydrogen evolution, affecting parameters like the Pd amount deposited, the Pd nanoparticles size and dispersion. The highest quantum efficiency (ϕ) obtained in this study was 11.8% and 41.2% under simulated solar and UVA irradiation, respectively, using Pd(0.24 wt%)/P25 in an aqueous solution of methanol (50 vol%). In the pilot-scale solar CPC, for Pd(0.24 wt%)//P25 catalysts in 5 vol% of methanol or glycerol as sacrificial agents, the quantum yield were 2.1 and 2.2%, respectively. When the concentration of the sacrificial agents decreased to 0.37 vol%, the quantum yields were 1.3 and 2.4% for methanol and glycerol, respectively. Compared to literature, the low noble metal content of these catalysts (0.25 wt%) seems to be a competitive factor considering their high price.

Optimization and prediction of pulsating heat pipe compound parabolic solar collector performances by hybrid deep belief network based bald eagle search optimizer

AbstractThe compound parabolic collector (CPC) with pulsating heat pipe (PHP) is developed for enhance the heat transfer rate, thermal efficiency and heat losses, and so forth. and working fluid plays a major role in this process. The thermal resistance, temperature, and thermal efficiency have been experimented with under different conditions, and heating periods were analyzed. In this, cobalt oxide (Co3O4) and graphene oxide (GO) added distilled water (DW) is used as the working fluid in the filing ratio of 50%. Bald eagle search optimization (BES) algorithm is used for optimizing the experimented values, and the better‐optimized values are used for hybrid BES based deep belief network (DBN) prediction. The maximum temperature obtained for experiment and optimization is 65 and 65.16161°C. 59% of thermal efficiency was obtained as maximum for experimentation, and 59.1542% of thermal efficiency was obtained as maximum for optimization. The maximum thermal resistance obtained for experimentation and optimization is 0.08 and 0.06938°C/W. In this, optimized outputs performed well than the experimental values. Besides, the hybrid DBN based BES algorithm is performed based on the optimized performances to predict the temperature, thermal efficiency and thermal resistance. Further, predicted outcomes are compared with the non‐hybrid neural networks such as DBN, CNN and ANN. DBN‐BES depicts low error values than the non‐hybrid neural networks. Overall, the proposed hybrid solar collector model and the hybrid nanoparticles added water helps to enhance the thermal characteristics with minimum heat loss.

Heterogeneous photocatalysis of moxifloxacin at a pilot solar compound parabolic collector: Elimination of the genotoxicity

Photocatalysis has been applied for the elimination or reduction concentration of emerging pollutants in water. One of them, is the moxifloxacin (MOX), a fluoroquinolone that have a potential to develop resistant bacteria and have been present toxicity. The MOX achieves the environment due to inefficient wastewater treatment and incorrect disposal. Aiming to find a sustainable solution for photocatalytic process, compound parabolic concentrator (CPC) reactors have been proposed. In this sense, the present study investigates the application of CPC reactor for the degradation of MOX using sunlight and artificial light (UV-A lamp). In addition, the acute toxicity for L. sativa seeds and A. cepa bulbs, as well as the MOX cytotoxicity and genotoxicity for A. cepa root were investigated before and after treatment. The MOX degradation was around 65% using the sunlight and 44% with the artificial light. This difference was due to the kind of incident radiation (direct and diffuse), as well as the type of radiation (visible and/or ultraviolet) used in the processes. For L. sativa the acute toxicity was eliminated after MOX treatment using sunlight. A. cepa root length increased before the treatment and reduced significantly after it, what can indicate hormesis occurrence. MOX cytotoxicity was not observed. In contrast, genotoxicity assays showed high frequency of chromosomal aberrations for MOX solution, indicating elevated genotoxicity that was eliminated after solar treatment. The transformation products of MOX after CPC reactor solar treatment did not show cytotoxicity and genotoxicity in A. cepa and acute toxicity in L. Sativa. The results indicates that photocatalysis in a CPC solar reactor is efficient for MOX toxicity removal in the treated solutions.

Radiative transfer in a Solar CPC Photoreactor using the First-Order Scattering Method

Abstract This manuscript analyzes the suitability of a recently proposed numerical method, the First-Order Scattering Method (FOS), to describe radiation transfer in a Solar Compound Parabolic Collector Photoreactor (CPCP). The study considers five different irradiance conditions ranging from fully diffuse to fully direct solar radiation, with 90 and 45° angled rays. Three photocatalysts at different loadings were considered: Evonik P25, Graphene Oxide, and Goethite, selected due to (1) their relevance in photocatalytic applications and (2) the availability of optical transport properties in the open literature. The study shows that the method is efficient and free of statistical noise, while its accuracy is not affected by the boundary condition’s complexity. The method’s accuracy is very high for photocatalysts with low to moderate albedos, such as Goethite and Graphene Oxide, displaying Normalized Absoluted Mean Error below 3%, i.e., comparable to the Monte Carlo (MC) Method’s statistical fluctuations.

Experimental investigation of solar compound parabolic collector using Al2O3/H2O nanofluid in a subtropical climate

Different solar concentrator technologies are used for low medium range temperature applications. In this paper, a non-tracking compound parabolic collector with a nanofluid is experimentally analyzed under real climate conditions of a typical sub-tropical climate Taxila, Pakistan. The collector used for the experimentation has concentration ratio of 4.17, collector area of 0.828 m2 and half acceptance angle of 24?. The heat transfer fluid used for the study is water based nanofluid with particles of Al2O3. The investigation is carried out at three different volumetric concentrations (0.025%, 0.05%, and 0.075%) of nanofluids at flowrates of 0.01 kg/s, 0.02 kg/s, 0.05 kg/s, and 0.07 kg/s are compared with base fluid (water). Comparison of system thermal efficiency, solar heat gain, and temperature difference is presented for different selected days in real climate conditions during months of March to May. It is observed that performance of the compound parabolic collector is improved by 8%, 11%, 14%, and 19%, respectively, at considered flow rates compared to water.

Compound parabolic solar collector – Performance evaluation as per standard test method and actual field conditions for industrial process heat application in Indian context

Industrial process heating has been identified as a potential field for solar thermal applications. In this paper, a comparative study was carried out on the performance of an individual solar collector under laboratory conditions and performance of the collector array under field condition. Compound Parabolic Concentrator (CPC) has been used as a solar collector for the application of boiler feed water preheating. The characterization of CPC has been done in liquid phase with water as a working fluid as per the standard, IS 16648 (Part-5):2017. The optical efficiency of the CPC is found to be 64.8% under standard test conditions. In the field, total 200 number of CPCs, each having 3 m2 area, were installed. The performance monitoring and evaluation of the actual installation was carried out over a period of 10 months. The system was designed to supply average 448,500 kWh- Thermal/year, saving the equivalent amount of fossil fuel. The comparative study of the performance of CPC collector under standard conditions and actual operating conditions in the field shows significant variation. The average variation in the performance was about 9% with a maximum variation of 14.7%. The major reasons behind the lower performance output than expected, attribute to the heat losses through the collector manifold and piping (3.9%), soiling of reflector and absorber of CPC (1.72%), uncertainties of instruments (1.49%) and other unaccounted losses like dislocation of the evacuated tubes from the original position, loss of vacuum through evacuated tubes, shadow effect, heat utilization pattern etc. (1.89%), which should be considered while designing the solar field to meet the required output.

An optical and energy absorption analysis of the solar compound parabolic collector photoreactor (CPCP): The impact of the radiation distribution on its optimization

This work presents a systematic and quantitative study of the optical and photon absorption performance of the solar compound parabolic collector photoreactor (CPCP) by a rigorous radiative Monte Carlo model. The parameters of the system, such as the properties of the receiver wall (refractive index and wall thickness), the collector reflectivity, the solar irradiation conditions and the optical thickness were varied to represent different experimental conditions and to investigate their impact on the radiation absorption of the CPCP. The results showed that the role of the receiver wall should be described accurately to determine an optimal CPCP design and to model its energy absorption field (the exclusion of the wall effect causes errors up to 12%). Finally, a new method to optimize solar CPCP was proposed based on an Energy Absorption Distribution Index (EADI). This index accounts for the cost of increasing the total rate of energy absorption (TREA) on the radiation distribution in the photoreactor volume and therefore is a more comprehensive approach than the extended method followed in the literature, which determines the optimum photocatalyst concentration only from the maximization of the TREA. An optimum apparent optical thickness interval was derived from these two approaches, which is τapp,opt = (2.20–3.58) ± 0.20 for all the solar irradiance conditions studied (diffuse or direct radiation at different incidence angles). Therefore, to operate CPCPs efficiently, the τapp should be at least 2.20 ± 0.20 and a further increase will depend on the intrinsic kinetics and hydrodynamics of the process, but should not exceed τapp = 3.58 ± 0.20.

Modeling of a Solar Heterogeneous Photocatalytic Reactor with TiO2 for Treatment of Wastewater Contaminated By Albendazole

Albendazole is an anthelmintic drug with antiangiogenic properties, which means that inhibits the development of new blood vessels. This causes a serious risk for the growth of fetus during pregnancy as a result. Heterogeneous photocatalysis has been proposed as an alternative for removal of this contaminant. In this study, a solar compound parabolic collector (CPC) photocatalytic reactor was modeled and simulated in order to describe the total organic carbon (TOC) degradation of commercial albendazole. The Six Flux Model approach (SFM) was used to estimate the Local Velocity Volumetric Rate of Photon Absorption (LVRPA) coupled with a Langmuir-Hinshelwood (L-H) kinetic model in order to describe the photocatalytic degradation of the TOC content of the contaminant and its photochemical oxidation products. The parameters of the L-H model were estimated from experimental data obtained with a catalyst loading of 0.6 g/l, initial pH of 5.0 and three different initial TOC concentrations of the commercial albendazole (159.95, 75.58 and 40 ppm). The rate constant (kT) and adsorption constant (K1), estimated from the parameter fitting, were 9.28×10-4 m1.5ppmW-0.5 s-1 and 3.02 × 10-2 ppm-1, respectively. The model was validated with experimental results, achieving a TOC removal of 40% with the lowest concentration of the contaminant. By simulating the process with different catalyst loadings, the maximum TOC removal was achieved with 0.21 g/L of TiO2.

Inactivation of water pathogens with solar photo-activated persulfate oxidation

The effect of solar activated persulfate oxidation and solar mild thermal heating on water disinfection (PS/solar) was demonstrated for the inactivation of E. coli and E. faecalis in both isotonic water (IW) and synthetic urban wastewater (SUWW). The process was studied in both bench-scale and pilot-scale (60 L CPC solar compound parabolic collector) reactors. The impact of solar ultraviolet (UV) and thermal increase on bacterial inactivation were separately studied. The thermal inactivation at 40 °C and 0.5 mM-PS shows a 3-log reduction value (LRV) for E. coli without lag phase and 5-LRV for E. faecalis with a lag phase of 1 h, during 4 h solar exposure. The thermal effect at 50 °C played a dominant role, with fast bacterial decay for both bacteria, which dominates the kinetics over the thermal activation of PS. In the presence of PS and solar irradiation, the combined thermal and UVA effects, accelerated the bacterial process. 6-LRV in E. coli and E. faecalis was observed after solar exposure periods of 20 min (solar dose), using 0.5 and 0.7 mM of PS in IW, respectively. Longer solar exposure times were required to attain similar LRV in synthetic urban wastewater, in the presence of 25 mg/L of organic matter, i.e. 80 and 100 min (solar dose) for E. coli and E. faecalis, respectively. These results were confirmed at pilot scale, where 60 L of IW were treated with 0.5 mM of PS in 50 min (solar dose). The PS/solar process uses low cost chemical reagents (0.5 mM-PS) and a free source of energy (solar radiation) for the treatment of wastewater and is able to achieve the high removals (6-LRV) of the two model faecal indicators of water contamination. This process opens a clear alternative to treat polluted water with organic matter and pathogens with implications in water-energy reclamation field.

A review of solar compound parabolic collectors in water desalination systems

ABSTRACT The essential role of water in all the human being daily activities is undeniable, and the consumption of it by increasing the human life standards is increasing considerably. The shortage of drinkable water for people around the globe is becoming a very serious problem; therefore seawater desalination via renewable energy technologies like solar energy would be an environmentally friendly and favorable way to deal with the water shortage problem. Solar collectors by absorbing the solar radiation and converting it to thermal energy can directly be utilized for various applications like solar cooling systems which operate based on the solar absorption and adsorption of solar heating energy, the solar central power generation systems, solar desalination systems, solar water disinfection systems, etc. This article presents an overview on more-than-twenty-years research and development on applications of solar Compound Parabolic Collectors (CPCs) in desalination systems. As non-imaging and stationary collectors, CPCs by having relatively wide angle apertures receive the incoming solar radiation and reflect it to the absorber. It was perceived that CPCs are cost effective and useful for low-temperature applications (T < 100 ºC) and medium temperature range (100ºC < T < 250ºC) within which they are capable of being used in solar desalination systems and during recent years there has been an increasing tendency in using them in solar desalination systems.

Influence of the incident radiation on the energy performance of two small-scale solar Organic Rankine Cycle trigenerative systems: A simulation analysis

In this paper, two innovative small-scale solar Organic Rankine Cycle (ORC) trigeneration plants are investigated and compared using a simulation analysis. In particular, the first plant (Plant 1) consists of a 146 m2 Compound Parabolic Collectors (CPC) solar field, a 3 m3 diathermic oil storage tank, a 3.5 kWe ORC plant and a 17 kWc absorption chiller, while the second plant (Plant 2) consists of a Linear Fresnel Reflectors (LFR) solar field of equal reflecting area, a phase change material storage tank equipped with reversible heat pipes, a 3.2 kWe ORC unit and the same 17 kWc absorption chiller as the former.The dynamic performance of the considered plants has been assessed for two Italian locations representative of the European Mediterranean area, Napoli and Messina, having a similar global radiation but a significantly different ratio of direct normal irradiance to diffuse irradiance. The comparison between the two different solar ORC trigeneration systems has revealed the great influence of the solar radiation on the effectiveness of such systems even for locations at similar latitudes. The energy production has been analysed both on a monthly and daily basis. Results have shown that while the performance of Plant 1 is not so sensitive to location and radiation conditions, Plant 2 is greatly affected by these parameters. Moreover, the higher condensing temperatures necessary in summer to supply the absorption chiller significantly limit the electrical efficiency of the solar CPC ORC. On the contrary, the LFR technology allows the achievement of higher temperatures and conversion efficiencies in summer, thus resulting especially suitable for solar cooling applications. In conclusion, this study has highlighted the importance of adequate technology selection with different radiation conditions in order to better exploit the potential of trigenerative solar ORC systems.

Numerical investigation and optimization of an experimentally analyzed solar CPC

In this study a compound parabolic collector (CPC) taken from literature was investigated optically and thermally through simulation. The collector was tested at different transversal and the longitudinal incident angles and the results showed us a total agreement between the present and the previous study where TracePro software was used. In addition, a new optical efficiency relationship was proposed and it was found that diverges significantly from the commonly used relationship as the reflector's shape losses and/or the absorber's diameter increase. Also, the CFD analysis results were validated from the previous study experimental data (4.2% mean divergence in thermal efficiency), something that reveals how sufficiently the real problem has been approached. Finally, an optimization process was followed in order to improve the collector's optical performance, while the novel CPC resulted from the optimization was compared with the initial design for the typical conditions of the 11th of June in Athens from 08:00 to 16:00, in order to examine the effect of different solar irradiation intensities in the comparison process. It was revealed that the novel design exceeds the initial one in all the examined hours. The design and the simulation of the collector were conducted via Solidworks Flow Simulation software.

Design configurations and possibilities of reflector shape for solar compound parabolic collector by ray tracing simulation

The objective of this paper is to study various possible configurations of reflectors of the compound parabolic collector (CPC) and select the suitable design as per the requirement. CPC is composed of two parabolic segments which show a wide range of design possibilities with its basic construction. This construction is based on design parameters like acceptance angle, rim angle, parabolic segments, truncation of parabolas, and location of the focus point and concluded for the suitable end application. A graphical ray tracing (GRT) simulation is used to examine the pattern of solar ray concentration for each design possibility. The various reflector configurations are generated from the design-morphological chart and compared on the basis of region and density of ray’s concentration. The research emphasizes a novel approach of constructing a CPC with possible design configurations which can find a great scope for further research. The various configurations would help engineers to select and design a CPC as per the requirement.

Photocatalytic degradation of bisphenol-A under UV-LED, blacklight and solar irradiation

This study aims at investigating the photocatalytic treatment of bisphenol-A (BPA) under various irradiation sources in order to identify cleaner and more sustainable technologies compared to conventional photocatalytic wastewater treatment systems. For this purpose, parallel experimental runs were carried out in two batch-operated slurry photoreactors under UVA irradiation provided by either a light-emitting diode (UV-LED) or a UV blacklight lamp (UV-BL), as well as in a solar compound parabolic collector (CPC) reactor under natural sunlight. The effect of key operating parameters, such as the initial BPA and TiO2 concentrations, water matrix, and treatment time, on the efficiency of the three photocatalytic systems was evaluated. The photocatalytic degradation of BPA was found to fit well with the pseudo-first-order kinetic model. BPA removal rate increased with catalyst concentration and with decreasing the initial concentration of BPA. The addition of humic acids was found to be inhibitory for all photocatalytic systems. At the best conditions assayed (C0 = 2.5 mg/L, TiO2 = 250 mg/L), BPA was completely degraded within 20, 30, and 120 min under UV-LED, solar, and UV-BL irradiation, respectively. The corresponding reaction rates were 0.230, 0.151, and 0.025 min−1, and TOC removal was 88, 67, and 33% after 90 min of treatment. In all cases, TiO2/UV-LED achieved the highest removal efficiency and it was found to be significantly more energy-efficient than the TiO2/UV-BL system. All in all, LED-driven photocatalysis was found to be advantageous over conventional TiO2/UV-BL systems in terms of performance and sustainability, and an appropriate alternative to solar photocatalysis in areas where sunlight is inadequate.

Degradation of emerging contaminants diclofenac, sulfamethoxazole, trimethoprim and carbamazepine by bentonite and vermiculite at a pilot solar compound parabolic collector

This study was aimed at evaluating bentonite (BEN) and vermiculite (VER) clays as photoactive materials for photodegrading a low-concentration (100 μg L−1) mixture of four emerging contaminants (ECs): trimethoprim (TMP), sulfamethoxazole (SMX), carbamazepine (CBZ) and diclofenac (DCF), using a solar advanced oxidation process. The experiments were performed in a stirred magnetic batch reactor (SMBR) and a solar pilot plant compound parabolic collector (CPC). The effect of mass, type of catalyst clay and H2O2 dose were evaluated, and the photodegradation of ECs was followed by Ultra Performance Liquid Chromatography (UPLC) and Dissolved Organic Carbon content (DOC). The results showed that the optimal dose of clays for EC degradation in both SMBR and CPC reactors was 0.2 g L−1. The photodegradation of ECs at optimal conditions by BEN and VER in the CPC decreased in the following order: DCF > TMP > SMX > CBZ and DCF > SMX > TMP > CBZ, respectively. The photodegradation rate constants for VER were 2, 32 and 1.1 times higher than those for BEN when SMX, CBZ and DCF were photodegraded with the optimal dose of clay, correspondingly. The percentage removal of DCF and SMX in experiments using BEN or VER was similar to TiO2. The TMP, SMX, CBZ and DCF degradation rate constants increased 9.05, 18.9, 2.08 and 23 times by adding [H2O2] = 200 mg L−1 and VER. The percentage removal of DOC was 16, 40 and 48% when VER and 50, 100 or 200 mg L−1 of hydrogen peroxide were added into the system, respectively. Similar results were obtained by adding BEN.

Exergy Analyses of Fabricated Compound Parabolic Solar Collector with Evacuated Tubes at Different Operating Conditions: Indore (India)

In this research work, compound parabolic solar collector (CPC) with evacuated tubes is fabricated. Main benefit of CPC is that there is no requirement of solar tracking system. With fabricated CPC; outlet temperatures of flowing fluid, instantaneous efficiencies, useful heat gain rates and inlet exergies (with and without considering Sun’s cone angle) are experimentally found. Observations are taken at different time intervals (1200, 1230, 1300, 1330 and 1400 h), mass flow rates (1.15, 0.78, 0.76, 0.86 and 0.89 g/s), ambient temperatures and with various dimensions of solar collector. This research work is concluded as; maximum instantaneous efficiency is 69.87% which was obtained with 0.76 g/s flow rate of water at 1300 h and 42°C is the maximum temperature difference which was also found at same time. Maximum inlet exergies are 139.733 and 139.532 kW with and without considering Sun’s cone angle at 1300 h, respectively. Best thermal performance from the fabricated CPC with evacuated tubes is found at 1300 h. Maximum inlet exergy is 141.365 kW which was found at 1300 h with 0.31 m aperture width and 1.72 m absorber pipe length.

Photo-Fenton treatment of saccharin in a solar pilot compound parabolic collector: Use of olive mill wastewater as iron chelating agent, preliminary results.

The aim of this work was to investigate the treatment of the artificial sweetener saccharin (SAC) in a solar compound parabolic collector pilot plant by means of the photo-Fenton process at pH 2.8. Olive mill wastewater (OMW) was used as iron chelating agent to avoid acidification of water at pH 2.8. For comparative purposes, Ethylenediamine-N, N-disuccinic acid (EDDS), a well-studied iron chelator, was also employed at circumneutral pH. Degradation products formed along treatment were identified by LC-QTOF-MS analysis. Their degradation was associated with toxicity removal, evaluated by monitoring changes in the bioluminescence of Vibrio fischeri bacteria. Results showed that conventional photo-Fenton at pH 2.8 could easily degrade SAC and its intermediates yielding k, apparent reaction rate constant, in the range of 0.64-0.82 L kJ-1, as well as, eliminate effluent's chronic toxicity. Both OMW and EDDS formed iron-complexes able to catalyse H2O2 decomposition and generate HO. OMW yielded lower SAC oxidation rates (k = 0.05-0.1 L kJ-1) than EDDS (k = 2.21-7.88 L kJ-1) possibly due to its higher TOC contribution. However, the degradation rates were improved (k = 0.13 L kJ-1) by increasing OMW dilution in the reactant mixture. All in all, encouraging results were obtained by using OMW as iron chelating agent, thus rendering this approach promising towards the increase of process sustainability.

Study of the intensification of solar photo-Fenton degradation of carbamazepine with ferrioxalate complexes and ultrasound

The intensification of the solar photo-Fenton system with ferrioxalate photoactive complexes and ultrasound applied to the mineralization of 15mg/L carbamazepine aqueous solution (CBZ) was evaluated. The experiments were carried out in a solar compound parabolic collector (CPC) pilot plant reactor coupled to an ultrasonic processor. The dynamic behavior of hydroxyl radicals generated under the different studied reaction systems was discussed. The initial concentrations of hydrogen peroxide and ferrous/oxalic acid and pH were found to be the most significant variables (32.79%, 25.98% and 26.04%, respectively). Under the selected optimal conditions ([H2O2]0=150mg/L; [Fe2+]0=2.5mg/L/[(COOH)2]0=12.1mg/L; pH=5) CBZ was fully degraded after 5min and 80% of TOC was removed using a solar photo-Fenton system intensified with ferrioxalate (SPFF). However, no improvement in the mineralization using SPFF process combined with ultrasound was observed. More mild pH conditions could be used in the SPFF system if compared to the traditional photo-Fenton (pH 3) acidic systems. Finally, a possible reaction pathway for the mineralization of CBZ by the SPFF system was proposed and therein discussed.

Energy Utilization Efficiency and Entrepreneurial Potential of a Solarbiomass Integrated Drying System

In absence of grid power in most of the production catchments in the North Eastern states of India, coupled with disruptive power situation in areas where it is available, agricultural products are invariably dried under traditional sun drying. Ginger and turmeric with high intrinsic qualities are two major spices produced in a formidable quantity in the region. Truckloads of raw ginger are transported to Delhi and other places, causing huge transit losses. A solar-biomass integrated (IDS) batch drying system was thus designed and developed with a capacity of 100 kg/batch. A compound parabolic solar collector coupled with bio-waste fired combustion and heating assembly was designed and attached to a drying chamber consisting of six trays and a wind turbine on the top to create the necessary draft controlled by butterfly valves and sliding gates. Thin layer drying experiments were carried out for drying of sliced ginger and turmeric. Fluidized bed dryer (FBD), electrical oven (EO) and open sun drying (OSD) were used for comparison. Effective moisture diffusivity in case of turmeric drying was nearly 21% more in comparison to ginger drying. Minimum specific energy consumption (SEC) occurred in IDS, and was 14 and 30 times less compared to FBD and OSD, respectively. Considering total heat available in the plenum chamber and latent heat of vapourization, the IDS showed 36.33% of overall energy utilization efficiency. A run up of 10 years and a break-even of 17.70 % was estimated, reflecting high entrepreneurial possibility of the developed IDS.