外文原文-关于油棕复叶的太阳能干燥系统的性能研究及改进潜能.PDF

Performances and improvement potential of solar drying system for palm oil fronds Ahmad Fudholi Kamaruzzaman Sopian M A Alghoul Mohd Hafi dz Ruslan Mohd Yusof Othman Solar Energy Research Institute Universiti Kebangsaan Malaysia 43600 Bangi Selangor Malaysia a r t i c l e i n f o Article history Received 12 August 2014 Accepted 21 January 2015 Available online 7 February 2015 Keywords Energy analysis Exergy analysis SMER Improvement potential Solar drying system Palm oil fronds a b s t r a c t In this study an indirect forced convection solar drying system was tested for drying of palm oil fronds The drying of 100 kg of palm oil fronds via solar drying system reduced the moisture content from 60 w b to 10 w b in 22 h 3 d of drying During the drying process the daily mean values of the drying chamber inlet temperature drying chamber outlet temperature drying chamber air temperature and solar radiation ranged from 26 C to 75 C 25 Ce65 C 26 Ce67 C and 96 W m2 to 1042 W m2 respectively with corresponding average values of 53 C 46 C 48 C and 580 W m2 At average solar radiation of about 600 W m2 and air fl ow rate 0 13 kg s the collector drying system and pick up effi ciencies were found about 31 19 and 67 respectively The specifi c moisture extraction rate SMER was 0 29 kg kWh The exergy effi ciency varied between 10 and 73 with an average of 47 In addition the improvement potential of solar drying system for palm oil fronds ranged from 8 W to 455 W with an average of 172 W 2015 Elsevier Ltd All rights reserved 1 Introduction Indonesia and Malaysia is the two largest producer of palm oil in the worlds Palm oil is one of the world s most rapidly expanding equatorial crops Malaysia has a tropical climate and is prosperous in natural resources The oil palm has a lifespan of over 200 years while the economic life is about 20e25 years Oil palm currently occupies the largest acreage of farmed land in Malaysia The totaloil palm acreage from 1970 to 2000 has increased from 320 to 3338 ha In the year 2003 there were more than 3 79 million hectares of land under palm oil cultivation occupying more than one third of the total cultivated area and 11 of the total land area of Malaysia One hectare of oil palm Elaeis gunineensis produces 10e35 tonnes of fresh fruit bunches FFB per year From 5 8 tonnes of FFB about 1 tonne of crude palm oil CPO is produced In Malaysia the total plantation area of oil palm was 4 487 957 ha in 2008 It has been reported that in 2005 there was a total of 423 palm oil mills having production capacity of about 89 million tones of FFB per year 1 2 Traditionally palm oil fronds were dried directly under the open sun drying Open sun drying very much dependent on the availability of sunshine requires large open space area and susceptible to contamination with foreign materials such as litters dusts and are exposed to birds rodents and insect However open sun drying results in low quality products and long drying times 3 Solar energy can play vital role in clean and sustainable energy sources Solar drying system was used in drying agricultural and marine products The designs and performance of solar drying systems for agricultural and marine products has been tested simulated and reported by many researchers 4e9 In Malaysia the Solar Energy Research Institute SERI at Universiti Kebangsaan Malaysia has carried out solar drying systems on many commodities such as chili tea herbal tea Centella medical herb fruits fi sh and seaweed 10 11 In the recent years exergy analysis has been widely used for the performance evaluation of thermal systems In the drying process the aim is to uses minimum amount of energy for maximum moisture removal for the desired fi nal conditions of the products 12 13 Several studies have been conducted on exergy analyses of food drying However detailed literature review for the present study has shown that there is no information on energy and exergy analyses of solar drying system for palm oil fronds In this previous Corresponding authors Tel 603 8911 8573 fax 603 8911 8574 E mailaddresses a fudholi A Fudholi k sopian K Sopian Contents lists available at ScienceDirect Renewable Energy journal homepage http dx doi org 10 1016 j renene 2015 01 050 0960 1481 2015 Elsevier Ltd All rights reserved Renewable Energy 78 2015 561e565 studies conducted on experimental of solar drying has not been investigated using energy and exergy analyses method However little data currently exist on performance of solar drying for palm oil fronds Feware found information about improvement potential of solar drying system in literature to the best of the authors knowledge The main objective of this study is performances and improvement potential of solar drying system for palm oil fronds Therefore this study as different other studies concentrates on the performance with energy and exergy analyses of solar drying sys tem for palm oil fronds 2 Material method and analysis The solar drying systemwas installed in the OPF FELDA Kuantan Malaysia The solar drying system consists of a fi nned double pass solar collector a blower and a fl at bed drying chamber The drying system is classifi ed as a forced convection indirect type A sche matic diagram of the solar dryer is shown in Fig 1 The width and length of the collector are 1 2 and 4 8 m respectively The solar collector array consists of 6 solar collectors is shown Fig 2 The cross section of double pass solar collector with fi nned absorber is shown Fig 3 The collector has a glass cover and the sides are insulated and painted black on an aluminum absorber plate The upper channel depth is 3 5 cm and the lower depth is 7 cm The bottom and sides of the collector are insulated with 2 5 cm thick fi berglass wool to minimize heat losses Air initially enters the Fig 1 Schematic diagram of solar drying system Fig 2 The collectors of solar drying system Fig 3 The schematic of a double pass solar collector with fi nned absorber Table 1 Equation of energy and exergy analysis 14e17 ParametersSymbolUnitPerformance indices equation The thermal effi ciency hc hc mC To Ti SAc 1 The system effi ciency of forced convection hd hd WL SAc Pf 2 Pick up effi ciencyhp hp h0 hi has hi W vrt has hi 3 The specifi c moisture extraction rate SMERkg kWh SMER W Pt 4 The weight of water evaporated from the product Wkg W mo Mi Mf 100 Mf 5 The initial total crop mass mokg Mass fl ow rate of dry air m kg s The latent heat of water vaporization at the exit air temperature LJ kg The collector areaAcm2 The solar radiationSW m2 The fan powerPfW The total energy input to the dryer PtkW The exergy effi ciency hEx da hEx da Exdco Exdci 1 Exloss Exdci 6 The exergy outlet of the drying chamber Exdco Exdco mC Tdco Ta TalnTdco Ta 7 The exergy inlet of the drying chamber Exdci Exdci mC Tdci Ta TalnTdci Ta 8 The exergy lossExlossExloss Exdci Exdco 9 The specifi c heat of air CJ kg C The drying chamber input temperature Tdci C The drying chamber output temperature Tdco C The ambient temperature Ta C The improvement potential IPWIP 1 hEx Exloss 10 A Fudholi et al Renewable Energy 78 2015 561e565562 collector through the fi rst channel formed by the glass that covers the absorber plate and then through the second channel formed by the back plate and the fi nned absorber plate The drying chamber is 2 4 m in length 1 0 m in width and 0 6 m in height The palm oil fronds used in this study was obtained from OPF FELDA Kuantan Malaysia The drying process was conducted from 8 00 AM to 6 00 PM The solar drying systemwas shut down at night The drying process was continued until the next day and the process was repeated until the required equilibrium moisture content was reached For the experiments the solar drying system was loaded to its full ca pacity of 100 kg of palm oil fronds which was divided and equally distributed on 4 trays The palm oil fronds was also placed in a small tray positioned at the center of the dryer to determine the moisture loss by using a Camry R9364 digital electronic balance that was placed on the top center of the drying chamber The balance has an accuracy of 0 01 g The air temperature ambient collector inlet and collector outlet temperatures radiation intensity and air ve locity were measured The air temperatures before entering inside and outside the dryer chamber were also measured Relative hu midity sensors were installed in the inlet middle and outlet sec tions of the drying chamber An air fl ow DTA 4000 anemometer was used to determine the air fl ow velocity in the solar collector T type thermocouples and an LI 200 pyranometer with accuracies of 0 018 C and 1 respectively were used During the drying process the temperature and relative humidity in the solar dryer were recorded at 1 min intervals by using the ADAM Data Acquisition System which is connected to a computer The performances analysis energy and exergy analysis of solar drying system for palm oil fronds are given in Table 1 14e17 For energy analysis the thermal effi ciency of the solar collector is given byequation 1 The system drying effi ciency and pick up effi ciency are given by equations 2 and 3 respectively The specifi c mois ture extraction rate SMER given byequation 4 which the mass of water removed from a wet product is given by equation 5 For exergyanalysis the exergyeffi ciencyof the drying chamber is given by equation 6 The exergies equation for drying chamber and exergy loss during the solar drying process are given by equations 7 e 9 The improvement potential of solar drying process is given by equation 10 3 Results and discussion The experimental results showed that solar drying 100 kg of dry palm oil fronds without auxiliary heating to reduce the moisture content of 60 e10 within 22 h 3 d of drying During the 3 d drying 22 h the daily mean values of the drying chamber inlet temperature drying chamber outlet temperature drying chamber air temperature and solar radiation ranged from 26 C to 75 C 25 Ce65 C 26 Ce67 C and 96 W m2to 1042 W m2respectively with corresponding average values of 53 C 46 C 48 C and 580 W m2 as shown in Fig 4 and Fig 5 The drying temperature under solar drying continuously varied with increasing drying Fig 4 Solar radiation and temperatures inlet outlet and average of drying chamber from March 4 2011 to March 6 2011 Fig 5 Temperatures inlet and outlet of collector solar radiation and collector effi ciency from March 4 2011 to March 6 2011 Table 2 Performance of solar drying for palm oil fronds Parameter and performanceValueUnit Initial weight of palm oil fronds100kg Final weight of palm oil fronds38kg Initial moisture content wet basis 60 Final moisture content wet basis 10 Air mass fl ow rate0 13kg s Average solar radiation575W m2 Average ambient temperature33 C Average drying chamber temperature49 C Drying time22h Solar energy212kWh Blower energy5 5kWh Specifi c moisture extraction rate0 29kg kWh Overall collector effi ciency31 Overall drying effi ciency up to 10 wb19 Pick up effi ciency up to 10 wb67 Average exergy effi ciency up to 10 wb47 Average improvement potential up to 10 wb172W Fig 6 Exergies inlet outlet and loss and exergy effi ciency from March 4 2011 to March 6 2011 A Fudholi et al Renewable Energy 78 2015 561e565563 time The results revealed that the drying temperature in solar drying was greater than the ambient temperature The summary of the experimental results and observations are given inTable 2 The effi ciency of collector varies from 9 to 48 and the average effi ciency of collector was about 31 as shown in Fig 5 It is observed that at low solar radiation the thermal effi ciency of collector is increased Using exergy analysis of drying process minimum and maximum the exergy inlet outlet and loss about 16 W and 1485 W 4 W and 885 W and 11 W and 640 W respec tively with an average of 651 W 324 Wand 327 Wrespectively was observed The exergy inlet outlet and loss variationwith respect to time are given in Fig 6 Exergy inlet outlet and loss follow similar patterns as similarly reported by Fudholi et al 17 Akpinar 18 and Chowdhury et al 19 The variations in the exergy inlet outlet and loss of the solar drying process were caused by varia tions in the daily solar radiation The useful energy gained from the collector ranged from 253 W to 6236 W with an average of 3375 W as shown in Fig 7 A 0 29 kg kWh was obtained for the specifi c moisture rate SMER was calculated using equation 4 which the weight of water evaporated from the palm oil fronds obtained using equation 5 was 62 kg Use L 2383 kJ kg 662 Wh kg for T 50 C as shown in Table 3 20 t 22 h and S 557 W m2to equation 2 yielded a drying effi ciency of 19 During the solar drying process the exergy effi ciency was in the range of 10 e 73 with an average of 47 as shown in Fig 8 or Fig 6 By using equation 10 the values of improvement potential were found to be in the range of 8 and 455 W with an average of 172 W as shown in Fig 7 or Fig 8 4 Conclusion The drying of 100 kg of palm oil fronds via solar drying system took 22 h 3 d of drying to reduce the initial moisture content of 60 e10 The solar collector and drying system about 31 and 19 respectively at the average solar radiation of about 600 W m2and air fl ow rate of 0 13 kg s A minimum and maximum the collector effi ciency about 9 and 48 respectively were observed A 0 29 kg kWh was obtained for the specifi c moisture extraction rate SMER The exergy effi ciency varied between 10 and 73 with an average of 47 The improvement potential was found tobe in the range of 8 and 455 W with an average of 172 W Acknowledgments The authors would like to thank the Yayasan Felda for funding this research grant RMK9 RS DL 001 2007 and the Solar Energy Research Institute SERI Universiti Kebangsaan Malaysia for support References 1 Rupani PF Singh RP Ibrahim MH Esa N Review of current palm oil mill effl uent POME treatment method vermicomposting as a sustainable prac tice World Appl Sci J 2010 11 1 70e81 2 Singh RP Ibrahim MH Esa N Composting of waste from palm oil mill a sustainable waste management practice Rev Environ Sci Biotechnol 2010 9 331e44 3 Fudholi A Sopian K Ruslan MH Alghoul MA Sulaiman MY Review of solar dryers for agricultural and marine products Renew Sustain Energy Rev 2010 14 1 1e30 4 Fudholi A Othman MY Ruslan MH Sopian K Drying of Malaysian Capsicum annuum L red chili dried by open and solar drying Int J Photoenergy 2013 1e9 5 Amer BMA Hossain MA Gottschalk K Design and performance evaluation of a new hybrid solar dryer for banana Energy Convesion Manag 2010 51 813e20 6 Banout J Ehl P Havlik J Lojka B Polesny Z Verner V Design and performance evaluation of a double pass solar drier for drying of red chilli Capsicum annuum L Sol Energy 2011 85 506e25 7 Smitabhindu R Janjai S Chankong V Optimization of a solar assisted drying system for drying bananas Renew Energy 2008 33 1523e31 8 Bala BK Debnath N Solar drying technology potentials and developments J Fundam Renew Energy Appl 2012 2 1e5 9 El Sebaii AA Shalaby SM Solar drying of agricultural products a review Renew Sustain Energy Rev 2012 16 37e43 10 Fudholi A Othman MY Ruslan MH Mat S Sopian K Prospect and future of solar dryer for agricultural and marine product perspective Malaysia In Proc Of the 7th WSEAS int conf On renewable energy sources RES 13 2013 p 141e9 11 Sopian K Othman MY Zaidi SH Amin N Advanced solar assisted drying systems for marin