A realistic performance assessment for pilot-scale biodrying application: AHP-PROMETHEE approach

Effect of air-flow rate and turning frequency on bio-drying of dewatered sludge

Quality characteristics of cold-dried beef slices

In this paper, heating and humidification of air for space have been carried out by using a phase change material (PCM)-based solar-powered desiccant wheel air conditioning (SPDWAC) in winter. The analysis of the setup has been done at different air flow rates. At low and high air flow rates, system has mean thermal coefficient of performance of 0.121 and 0.172, respectively, and mean exergy efficiency of 0.0787 and 0.0846, respectively. The mean thermal coefficient of performance of the system at high air flow rate (127.23 kg h-1) is 1.42 times the low air flow rate (63.62 kg h-1) and average exergy efficiency of the system at high air flow rate is 1.07 times the low air flow rate. It is observed that with an increase in air flow rate, efficiency of the evacuated tube solar air collector (ETSAC) increases. The average efficiency of the ETSAC at high air flow rate is 15.60%. The maximum average energy efficiency (17.80%) and exergy efficiency (17.08%) of the PCM storage system have been obtained at high air flow rate. The overall performance of the system showed that the use of PCM storage is feasible to run the system in winter during the hours of darkness.

The performance analysis on the phase change material-based evacuated tube solar air collector was examined under consecutive and simultaneous charging and discharging modes. Acetamide was used as phase change material. The system performance was evaluated on the basis of the phase change material storage system energy efficiency, exergy efficiency, collector efficiency, the instantaneous energy stored in the phase change material and total energy stored by the system at low and high air flow rates of 0.018 kg/s and 0.035 kg/s, respectively. The maximum average efficiency (17.9%) of the collector was obtained at a high air flow rate during simultaneously charging and discharging of the phase change material. The results obtained demonstrate that the system is more effective when it is operated with high air flow rate during simultaneously charging and discharging of the phase change material. The average total energy at high air flow rates is 1.01 to 1.02 times more in comparison to that at low air flow rates. The findings show the feasibility of the phase change material-based evacuated tube solar air collector for producing hot air for space heating during consecutive and simultaneous charging and discharging of the phase change material in northen Indian climatic conditions. This system would be relevant in areas with good sunlight.

Two similar solar drying units were designed, constructed and evaluated for drying basil leaves (Ocimum basilicum L.) as a medicinal and aromatic plant at initial moisture content of 590.73% (d.b) or 85.52% (w.b) under Fayoum conditions by using heated air. Each drying unit consists of a flat-plate solar collector, which oriented and tilted with an optimum tilt angle and attached with drying chamber. The drying experiments were carried out to examine the effect of basil leaves thicknesses (2, 4 and 6 cm) and airflow rate (0.015 and 0.025 m3.sec-1) on the basil leaves drying rate. The obtained results indicated that the daily average total solar radiation flux incident on the tilted solar collector surface (29.30 MJ. m-2.day-1) was greater than that incident on the horizontal surface (24.30 MJ.m-2.day-1) by 24.58%. The output higher air temperatures were obtained at the lower airflow rate whereas; the energy gained to the air from the solar collector was relatively higher at the higher airflow rate as compared with the lower airflow rate. Consequently, the solar collector with the higher airflow rate increased the overall thermal efficiency by 5.46% as compared to the lower airflow rate. The moisture content of dried basil leaves was strongly affected by the basil leaves thickness and the airflow rate. The final moisture content of dried basil leaves ranged from (11.52% to 14.58% d.b) depending on the drying temperature cycle. Very small changes were observed in the colour and shape of heated-air dried basil leaves as compared to that dried at direct sun rays. The essential oil contents of dried basil leaves were slightly higher for the drying unit with the higher airflow rate as compared with the corresponding values obtained from the drying unit with the lower airflow at all basil leaves thicknesses. While on Contrast, total chlorophylls contents were slightly higher for the drying unit with the lower airflow rate as compared with the corresponding values obtained from the drying unit with the higher airflow at all basil leaves thicknesses. Effect of the individual variables (airflow rate, basil leaves thickness, moisture removed, and their interactions) on the drying rate was statistically analyzed. Under the conditions of this study, the optimum depth to dry basil leaves by using heated air is 4 cm.

Food drying process in tunnel dryer was modeled from Keey's drying model and experimental drying curve, and optimized in operating conditions consisting of inlet air temperature, air recycle ratio and air flow rate. Radish was chosen as a typical food material to be dried, because it has a typical drying characteristics of food and quality indexes of ascorbic acid destruction and browning in the drying. Stricter quality retention constraint required higher energy consumption in minimizing the objective function of energy consumption under constraints of dried food quality. Optimization results of cocurrent and counter current tunnel drying showed higher inlet air temperature, lower recycle ratio and higher air flow rate with shorter total drying time. Compared with cocurrent operation counter current drying used lower air temperature, lower recycle ratio and lower air flow rate, and appeared to be more efficient in energy usage. Most of consumed energy was analyzed to be used for air heating and ...

Shortages of feedstock supply due to seasonal availability, high transportation costs, and lack of biomass market are creating serious problems in continues operation of bioenergy industry. Aiming at this problem, utilization of blended feedstock is proposed. In this work blends of two different biomasses (wood and coconut shells) were co-gasified using externally heated downdraft gasifier. The effects of varying biomass blending ratio and airflow rate on gaseous components of syngas and its heating value were investigated. The results obtained from the experiments revealed that W20:CS80 blend yielded higher values for H 2 (20 Vol.%) and HHV (18 MJ/Nm 3 ) as compared to the other blends. The higher airflow rate has a negative effect on syngas profile and heating value. The CO and CH4 were observed higher at the start of the process, however, CO was observed decreasing afterward, and the CH 4 dropped to 5.0 Vol.%. The maximum H 2 and CH 4 were obtained at 2.5 LPM airflow rate. The process was noticed more stable at low air flow rates. The HHV was observed higher at the start of process at low airflow rate. It is concluded that low airflow rate and a higher ratio of coconut shells can improve the syngas quality during co-gasification.

A solar drying unit was developed and constructed for drying onion slices under Fayoum conditions. The drying unit consists of a solar collector, which oriented and tilted with an optimum tilt angle and attached with drying chamber. The drying experiments were carried out to examine the effect of onion slice thicknesses (3, 6 and 10 mm) and airflow rate (2.4 and 1.6 m 3 .min -1 ) on the onion slices drying rate. The obtained results indicated that the daily average total solar radiation flux incident on the tilted solar collector surface (7.32kWh.m -2 .day -1 ) was greater than that incident on the horizontal surface (6.13kWh.m -2 .day -1 ) by 19.41%. The higher air temperatures were obtained at the lower airflow rate (1.6 m 3 .min. -1 ) whereas; the amount of heat gained to the air from the solar collector was relatively higher at the higher airflow rate as compared with the lower airflow rate. Consequently the higher efficiency of the solar collector was obtained at the higher airflow rate. The solar collector with the higher airflow rate increased the overall thermal efficiency by 12.56% as compared to the lower airflow rate. The moisture content of dried onion slices was strongly affected by the onion slices thickness and the airflow rate. The final moisture content of dried onion slices ranged from (6.8% to 7.7% dry-basis) depending on the drying temperature cycle. Effect of the individual variables (airflow rate, onion slice thickness, moisture removed, and their interactions) on the drying rate was statistically analyzed. A forward step-wise regression technique was applied to arrive at a reasonable good best set of independent variables. The coefficient of determination (R 2 ) was above 0.97 when

Application of a simplified mathematical model to estimate the effect of forced aeration on composting in a closed system

Influence of input waste feedstock on solid recovered fuel production in a mechanical treatment plant

Comparative analysis of wood and solid recovered fuels gasification in a downdraft fixed bed reactor

The aim of the present work is to investigate an effect of primary air draft and flow rate on thermal performance and CO/CO2 emission of the domestic stove fed with the briquette of coconut shell. The work is conducted by following the simplified water boiling test method. Firstly, the stove is tested under natural draft mode (ND). Secondly, the stove is run under force draft mode at two different air flow rates, such that 0.013 m3/s (FD 1) and 0.020 m3/s (FD 2). In the present work, temperatures of water, flame, and stove are measured. Thermal performance of the stove in terms of fuel consumption rates (FCR), firepower (P), heating rates (Ew), thermal efficiency (ηT), and specific useful energy (SUE) is calculated and analyzed. CO/CO2 in flue gas is also measured and analyzed. The result indicates that air flow rate affects the thermal performance and CO/CO2 emission of the stove. Increasing air flow rate enhances the FCR, P, Ew, ηT, and SUE. On the other hand, increasing air flow rate reduces CO/CO2 in flue gas. The highest values of FCR, P, Ew, ηT, and SUE are obtained at the higher air flow rate. The values are 1.43 kg/h, 8.024 kW, 0.294 kW, 3.670%, and 741.975 kJ/kg, correspondingly. Meanwhile, the lowest CO/CO2 of 0.009 is observed at the higher air flow rate.

Lean ignition and blow-off behaviour of butyl butyrate and ethanol blends in a gas turbine combustor

Experimental evaluation of used engine oil based thermal energy storage coupled with novel evacuated tube solar air collector (NETAC)

The effect of surfactants on air–water annular and churn flow in vertical pipes. Part 2: Liquid holdup and pressure gradient dynamics