13supawan parameters 335-346100-130oC (crumb rubber) could be explained by the empirical model,...
Transcript of 13supawan parameters 335-346100-130oC (crumb rubber) could be explained by the empirical model,...
æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ”À√—∫°“√«‘‡§√“–Àå°“√Õ∫·Àâ߬“ß∏√√¡™“µ‘
ÿ¿«√√≥ Ø‘√–«≥‘™¬å°ÿ≈1 ÿ‡∑’¬π –π—¬
2 ™≠“πÿ™ · ß«‘‡™’¬√
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·≈– ¬ÿ∑∏π“ Ø‘√–«≥‘™¬å°ÿ≈4
AbstractTirawanichakul, S.1, Sanai, S.1, Sangwichien, C.1 and Tirawanicahkul, Y.2
Parameters for the analysis of natural rubber dryingSongklanakarin J. Sci. Technol., May 2007, Suppl 2 : 335-346
The purpose of this research was to study and develop a mathematical model of essential parameters
affecting drying process in terms of equilibrium moisture content (EMC), apparent density, percentage of
void fraction, specific heat capacity and effective diffusion coefficient (D) for three kinds of natural rubber.
Three raw natural rubber samples in this work used crumb rubber, rubber stick and rubber sheet with an
initial moisture content ranging between 30 and 45% wet-basis that were normally used for producing the
standardized Thai rubber (STR) block rubber and air dried rubber sheet (ADS). The results show that the
apparent density and specific heat of all natural rubber samples were linearly dependent on the moisture
content whilst the percentage of void fraction of natural rubber was inversely related to moisture content.
The isotherm EMC equations formulated by the Herderson model for the crumb rubber and rubber stick
were the best fitting with the experimental values, and for the rubber sheet. The isotherm EMC equation
using the Halsey model was the most appropriable to the experimental results. In addition, the effective
diffusion coefficients of all natural rubber materials, which were the function of drying temperature and
π‘æπ∏åµâπ©∫—∫
1Department of Chemical Engineering, Faculty of Engineering, 2Department of Physics, Faculty of Science,
Prince of Songkla University, Hat Yai, Songkhla, 90112 Thailand.
1ª√.¥. (‡∑§‚π‚≈¬’æ≈—ßß“π) ºŸâ™à«¬»“ µ√“®“√¬å
2π—°»÷°…“ª√‘≠≠“‚∑À≈—° Ÿµ√ «».¡. “¢“«‘»«°√√¡‡§¡’
3Ph.D. (Chemical
Engineering) ºŸâ™à«¬»“ µ√“®“√¬å ¿“§«‘™“«‘»«°√√¡‡§¡’ §≥–«‘»«°√√¡»“ µ√å 4ª√.¥. (‡∑§‚π‚≈¬’æ≈—ßß“π) ºŸâ™à«¬»“ µ√“®“√¬å
¿“§«‘™“øî ‘° å §≥–«‘∑¬“»“ µ√å ¡À“«‘∑¬“≈—¬ ߢ≈“π§√‘π∑√å Õ”‡¿ÕÀ“¥„À≠à ®—ßÀ«—¥ ߢ≈“ 90112
Corresponding e-mail : [email protected]
√—∫µâπ©∫—∫ 21 ‡¡…“¬π 2549 √—∫≈ßæ‘¡æå 27 °—𬓬π 2549
Songklanakarin J. Sci. Technol.
Vol. 29 (Suppl.2) May 2007: Grad. Res. 336
Parameters for the analysis of natural rubber drying
Tirawanichakul, S., et al.
drying time, were in range of 10-6-10-7 m2/hr. However, prediction of the evolution of moisture content of
thin-layer drying under the condition of drying temperatures of 40-70oC (rubber stick and rubber sheet) and
100-130oC (crumb rubber) could be explained by the empirical model, which was the function of drying
temperature and drying time.
Key words : effective diffusion coefficient, equilibrium moisture content, mathematical model,natural rubber
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Cousin ·≈–§≥– (1993) ‰¥â∑”°“√»÷°…“°“√Õ∫·Àâ߇»…¬“ß∏√√¡™“µ‘ (Natural Crumb Rubber) æ∫«à“™à«ß
°“√Õ∫·Àâß¡’ 3 ™à«ß ™à«ß·√°™—Èπ¬“ß®–Õ‘Ë¡µ—«¥â«¬πÈ” Õÿ≥À¿Ÿ¡‘¢ÕßÕ“°“»·≈–‡¡Á¥¬“ß®–‡∑à“°—∫Õÿ≥À¿Ÿ¡‘¢Õß°√–‡ª“–‡ªï¬°„π™à«ß∑’Ë 2 ‡°‘¥°“√Õ∫·Àâß·∫∫Õ—µ√“§ß∑’Ë (constant rate)Õÿ≥À¿Ÿ¡‘ §«“¡™◊Èπ —¡æ—∑∏å¢ÕßÕ“°“»·≈–ª√‘¡“≥πÈ”„π¬“ß≈¥≈ßÕ¬à“ß√«¥‡√Á« ™à«ß∑’Ë 3 ®–‡ªìπ™à«ßÕ—µ√“Õ∫·Àâß≈¥≈ß(Falling rate)
Naon ·≈–§≥– (1993) ∑”°“√∑¥≈ÕßÕ∫·Àâ߬“ß∏√√¡™“µ‘·≈–æ—≤π“·∫∫®”≈Õß∑“ߧ≥‘µ»“ µ√å‡æ◊ËÕÀ“ ¿“«–∑’ˇÀ¡“– ¡ ”À√—∫Õ∫·Àâ߬“ß∏√√¡™“µ‘ ‚¥¬„™â‡§√◊ËÕßÕ∫·Àâß¢π“¥ 3x1x2 ≈∫.‡¡µ√ §«“¡‡√Á«≈¡ 0-5 ‡¡µ√/«‘π“∑’Õÿ≥À¿Ÿ¡‘Õ“°“» 20-150oC §«“¡™◊Èπ —¡æ—∑∏å 0-100% ®“°º≈°“√∑¥≈Õß æ∫«à“ Õ—µ√“°“√Õ∫·Àâß®–¢÷ÈπÕ¬Ÿà°—∫Õÿ≥À¿Ÿ¡‘‡«≈“°“√Õ∫·Àâß ·≈–§à“§«“¡™◊Èπ —¡æ—∑∏å §à“ —¡ª√– ‘∑∏‘Ï°“√∂à“¬‚Õ𧫓¡√âÕπ (h) ®–¢÷ÈπÕ¬Ÿà°—∫Õÿ≥À¿Ÿ¡‘¢Õß«— ¥ÿ·≈–Õÿ≥À¿Ÿ¡‘¢ÕßÕ“°“»‡¡◊ËÕ‰¥â§à“æ“√“¡‘‡µÕ√åµà“ßÊ ®“°°“√Õ∫·Àâß™—Èπ∫“ß ·≈–π”§à“æ“√“¡‘‡µÕ√å‡À≈à“π—Èπ‰ª∑”π“¬Õ—µ√“°“√Õ∫·Àâß™—ÈπÀπ“¥â«¬·∫∫®”≈Õß∑“ߧ≥‘µ»“ µ√å æ∫«à“º≈®“°·∫∫®”≈Õß„°≈⇧’¬ß°—∫º≈°“√∑¥≈Õß ‚¥¬°”À𥧫“¡™◊Èπ ÿ¥∑⓬À≈—ß°“√Õ∫·Àâ߇∑à“°—∫ 0.8% ·≈–®“°°“√π”·∫∫®”≈Õ߉ª„™â‡ª√’¬∫‡∑’¬∫‡§√◊ËÕßÕ∫·Àâß Trolley ·∫∫°÷ËßÕ—µ‚π¡—µ‘∑’Ë„™â„πÕÿµ “À°√√¡æ∫«à“„Àâº≈„°≈⇧’¬ß°—π∑—Èߥâ“𧫓¡™◊Èπ Õÿ≥À¿Ÿ¡‘ §«“¡™◊Èπ —¡æ—∑∏å ·≈–æ≈—ßß“π∑’Ë„™â„π°“√Õ∫·Àâß
∏π‘µ ·≈–§≥– (2542) ‰¥â»÷°…“·≈–À“·π«∑“ß°“√Õ∫·Àâß∑’ˇÀ¡“– ¡¢Õ߇¡≈Á¥„π¡–¡à«ßÀ‘¡æ“πµå·∫∫∂“¥À¡ÿπ‚¥¬ √â“߇§√◊ËÕßÕ∫·Àâ߇¡≈Á¥„π‡¡≈Á¥¡–¡à«ßÀ‘¡æ“πµå·∫∫∂“¥À¡ÿπ·≈–æ—≤π“·∫∫®”≈Õß∑“ߧ≥‘µ»“ µ√å º≈°“√‡ª√’¬∫‡∑’¬∫°“√∑¥≈Õß·≈–·∫∫®”≈Õß æ∫«à“ ·∫∫®”≈Õß “¡“√∂∑”𓬰“√Õ∫·Àâ߉¥â¥’ ‚¥¬∑’ËÕ—µ√“°“√Õ∫·Àâß®–„°≈⇧’¬ß°—∫°“√∑¥≈Õß ·≈–„π°“√Õ∫·Àâߧ«√§”π÷ß∂÷ߧÿ≥¿“æ¢Õߺ≈‘µ¿—≥±å ‡«≈“∑’Ë„™â„π°“√Õ∫·Àâß·≈–æ≈—ßß“π∑’Ë„™â„π°“√Õ∫·Àâß
Wetchacama ·≈–§≥– (2002) ‰¥â∑”°“√»÷°…“À“·∫∫®”≈Õßæ“√“¡‘‡µÕ√åÕ∫·ÀâߢÕß¡–¡à«ß·™àÕ‘Ë¡ æ∫«à“§«“¡™◊Èπ ¡¥ÿ≈≈¥≈ßµ“¡Õÿ≥À¿Ÿ¡‘ ¡°“√¢Õß BET (1938)Õ∏‘∫“¬º≈°“√∑¥≈Õ߉¥â¥’∑’Ë ÿ¥ º≈°“√∑¥≈ÕßÕ∫·Àâß¡–¡à«ß·™àÕ‘Ë¡· ¥ß„Àâ‡ÀÁπ«à“ —¡ª√– ‘∑∏‘Ï°“√·æ√à‡æ‘Ë¡¢÷Èπµ“¡Õÿ≥À¿Ÿ¡‘¢Õß°“√Õ∫·Àâß §«“¡Àπ“·πàπ≈¥≈ßµ“¡§«“¡™◊Èπ‡√‘Ë¡µâπ
Songklanakarin J. Sci. Technol.
Vol. 29 (Suppl.2) May 2007: Grad. Res. 338
Parameters for the analysis of natural rubber drying
Tirawanichakul, S., et al.
·≈–§«“¡√âÕπ®”‡æ“–‡æ‘Ë¡¢÷Èπµ“¡ª√‘¡“≥§«“¡™◊Èπ‡√‘Ë¡µâπ¥â«¬Tabatabaee ·≈–§≥– (2004) ‰¥â∑”°“√»÷°…“°“√
Õ∫·Àâß™—Èπ∫“ß·≈–≈—°…≥–‡©æ“–¢Õß°“√ rewetting ‡¡≈Á¥¢â“« “≈’ æ∫«à“ ¡°“√¢Õß Page (1949) “¡“√∂Õ∏‘∫“¬°“√Õ∫·Àâß™—Èπ∫“ß·≈–°“√ rewetting ¢â“«‰¥â¥’∑’Ë ÿ¥
Tirawanichakul ·≈– Tirawanichakul (2004)‰¥â»÷°…“ª√‘¡“≥§«“¡™◊Èπ ¡¥ÿ≈¢Õ߇»…¬“ß´÷Ë߇ªìπ«—µ∂ÿ¥‘∫„π°“√º≈‘µ¬“ß·∑àß‡Õ ∑’Õ“√å ¿“¬„µâ ¿“«–§ß∑’Ë∑’ËÕÿ≥À¿Ÿ¡‘ 35-60oC §«“¡™◊Èπ —¡æ—∑∏å 10-90% ®“°º≈°“√∑¥≈Õ߉¥âπ” ¡°“√À“§à“§«“¡™◊Èπ ¡¥ÿ≈ 4 ¡°“√ ∑”°“√‡ª√’¬∫‡∑’¬∫‚¥¬æ‘®“√≥“§à“§«“¡·ª√ª√«π 2 µ—« §◊Õ SSE (sum ofsquares error) ·≈– SD (Standard deviation) æ∫«à“ ¡°“√¢Õß Halsey (1948) ‡ªìπ ¡°“√∑’ˇÀ¡“– ¡∑’Ë ÿ¥∑’Ë®–„™â„π°“√∑”π“¬§à“§«“¡™◊Èπ ¡¥ÿ≈¢Õ߬“ß ´÷Ëßæ∫«à“°“√§“¬§«“¡™◊Èπ¢Õ߬“ß —¡æ—π∏å°—∫Õÿ≥À¿Ÿ¡‘·«¥≈âÕ¡∑’˧«“¡™◊Èπ —¡æ—∑∏å§ß∑’Ë πÕ°®“°π’Ȭ—ßæ∫«à“Õ—µ√“°“√Õ∫·Àâߢ÷Èπ°—∫√–¬–‡«≈“·≈–Õÿ≥À¿Ÿ¡‘Õ∫·Àâß
®“°º≈ß“π«‘®—¬∑’Ë°≈à“«¡“¢â“ßµâπ √ÿª‰¥â«à“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ‰¥â·°à §à“§«“¡™◊Èπ ¡¥ÿ≈ §à“§«“¡Àπ“·πàπª√“°Ø‡ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“» §à“§«“¡√âÕπ®”‡æ“– ·≈–§à“ —¡ª√– ‘∑∏‘Ï°“√·æ√৫“¡™◊È𠇪ìπµâ𠇪ìπæ“√“¡‘‡µÕ√å∑’Ë„™â ”À√—∫°“√«‘‡§√“–Àå°“√Õ∫·Àâß ‡æ◊ËÕ„™â»÷°…“À“·π«∑“ß°“√Õ∫·Àâß∑’ˇÀ¡“– ¡∑—Èß„π¥â“πæ≈—ßß“π §ÿ≥¿“æ∑—Èß∑“ß°“¬¿“æ·≈–∑“߇§¡’ ”À√—∫º≈‘µ¿—≥±åπ—ÈπÊ ‰¥â¥’ Õ¬à“߉√°Áµ“¡°“√»÷°…“À“æ“√“¡‘‡µÕ√åæ◊Èπ∞“π ”À√—∫°“√Õ∫·Àâ߬“߇™à𠇻…¬“ß°âÕπ ¬“ß·ºàπ¥‘∫ √«¡∑—Èߺ≈‘µ¿—≥±å¬“ß∏√√¡™“µ‘‡™à𠬓ß∂⫬ ¬“߇ âπ ‡À≈à“π’Ȭ—߉¡à¡’√“¬ß“π‰«â ¥—ßπ—Èπß“π«‘®—¬π’È®÷ß¡’«—µ∂ÿª√– ߧå‡æ◊ËÕ»÷°…“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ”À√—∫«‘‡§√“–Àå°“√Õ∫·Àâ߬“ß∏√√¡™“µ‘ ‰¥â·°à §à“§«“¡™◊Èπ ¡¥ÿ≈§à“§«“¡Àπ“·πàπª√“°Ø ‡ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“» §à“§«“¡√âÕπ®”‡æ“– ·≈–§à“ —¡ª√– ‘∑∏‘Ï°“√·æ√à ·≈–æ—≤π“·∫∫®”≈Õß∑“ߧ≥‘µ»“ µ√å¢Õß ¡°“√Õ∫·Àâß™—Èπ∫“ß ”À√—∫¬“ß·µà≈–™π‘¥ ‡æ◊ËÕ„™âÀ“·π«∑“ß°“√Õ∫·Àâß∑’ˇÀ¡“– ¡¿“¬„µâ ¿“«–¢ÕßÕ“°“»·«¥≈âÕ¡Àπ÷ËßÊ µàÕ‰ª
«‘∏’°“√«‘®—¬
·∫àßÕÕ°‡ªìπ¢—ÈπµÕπ ¥—ßπ’È
1. °“√‡µ√’¬¡§«“¡™◊Èπ∑’Ë„™â„π°“√∑¥≈Õß
¬“ß∏√√¡™“µ‘∑’Ëπ”¡“∑¥≈Õß ‰¥â·°à ‡»…¬“ß°âÕπ ¬“ß·ºàπ ¬“ß‡ âπ µ—¥‡ªìπ™‘Èπ‡≈Á°Ê „Àâ¡’¢π“¥„°≈⇧’¬ß°—∫‚√ßß“ππ”¡“‡µ√’¬¡§«“¡™◊Èπ¢Õ߬“ß‚¥¬°“√æàπ≈–ÕÕßπÈ” ‡°Á∫‰«â„π¿“™π–ªî¥ ·™à§â“ߧ◊π‰«â 1-2 «—π ‡æ◊ËÕ„À≥⧫“¡™◊Èπª√–¡“≥20-65% ¡“µ√∞“π·Àâß ·≈â«®÷ßπ”ÕÕ°¡“∑¥≈Õß
°àÕπ∑”°“√∑¥≈Õßπ”¡“À“§«“¡™◊Èπµ“¡¡“µ√∞“π¢Õß AOAC (1995)
2. °“√∑¥≈ÕßÀ“§«“¡™◊Èπ ¡¥ÿ≈·∫∫§“¬§«“¡™◊Èπ
𔇻…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ ª√–¡“≥ 30-50 °√—¡ ‰ª∫√√®ÿ„πµ–·°√ß√Ÿª∑√ß°√–∫Õ° ·≈â«π”‰ª·¢«π‰«â„π¢«¥ ∫√√®ÿ “√≈–≈“¬‡°≈◊ÕÕ‘Ë¡µ—«µà“ßÊ §◊Õ LiCl, NaCl,KNO
3, MgCl
2.6H
2O, Mg(NO
3)2.6H
2O, (NH
4)2.SO
4
ªî¥Ω“¢«¥„Àâ·πàπ ∑”Õ¬à“ß≈– 2 ¢«¥ ‚¥¬µâÕß√–«—߉¡à„Àâ “√≈–≈“¬‡°≈◊Õ —¡º— °—∫µ–·°√ß ªî¥Ω“¢«¥„Àâ·πàπ π‘∑𔉪„ à„πµŸâÕ∫´÷Ëߧ«∫§ÿ¡Õÿ≥À¿Ÿ¡‘‰¥â ‚¥¬„™âÕÿ≥À¿Ÿ¡‘ 30oC‡ªìπ‡«≈“ 10-30 «—π ‡æ◊ËÕ√Õ„Àâ√–∫∫‡¢â“ Ÿà ¡¥ÿ≈∑“ߧ«“¡™◊Èπ√–À«à“߬“ß°—∫ “√≈–≈“¬‡°≈◊ÕÕ‘Ë¡µ—« ·≈â«®÷ß𔉪À“§à“§«“¡™◊Èπ ¡¥ÿ≈ À≈—ß®“°π—Èπ∑”°“√∑¥≈Õ߇™àπ‡¥‘¡·µà‡ª≈’ˬπÕÿ≥À¿Ÿ¡‘‡ªìπ 35, 40, 45, 50, 55 ·≈– 60oC µ“¡≈”¥—∫
3. °“√À“§«“¡Àπ“·πàπª√“°Ø
∑¥≈Õß‚¥¬π”µ—«Õ¬à“ß∑’ˇµ√’¬¡‰¥â®“°À—«¢âÕ 1 ∑’褈Ҥ«“¡™◊Èπµà“ßÊ ¡“„ à„π¿“™π–√Ÿª∑√ß°√–∫Õ°∑’Ë¡’ª√‘¡“µ√250 ≈∫.´¡. ‚¥¬§àÕ¬Ê „ à®π‡µÁ¡¿“™π– ·≈â«π”‰ª™—ËßπÈ”Àπ—° ·≈–§”π«≥À“§«“¡Àπ“·πàπª√“°Ø‡©≈’ˬ¢Õß·µà≈–§à“§«“¡™◊Èπ¢Õßµ—«Õ¬à“ß ·≈–∑”°“√∑¥≈Õß´È”∑’Ë·µà≈–§«“¡™◊Èπ 3 §√—Èß
§”π«≥§à“§«“¡Àπ“·πàπª√“°Øµ“¡ ¡°“√ (1)
ρ = mVb
(1)
‡¡◊ËÕ ρ §◊Õ §«“¡Àπ“·πàπª√“°Ø¢Õߢ⓫‡ª≈◊Õ°,°°./≈∫.‡¡µ√
m §◊Õ §«“¡™◊Èπ‡√‘Ë¡µâπ¢Õߢ⓫‡ª≈◊Õ°,% ¡“µ√∞“π·Àâß
Vb§◊Õ ª√‘¡“µ√¿“™π–, ≈∫.‡¡µ√
«. ߢ≈“π§√‘π∑√å «∑∑.
ªï∑’Ë 29 (©∫—∫摇»… 2) æ.§. 2550 : ∫—≥±‘µ»÷°…“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ”À√—∫°“√«‘‡§√“–Àå°“√Õ∫·Àâ߬“ß∏√√¡™“µ‘
ÿ¿«√√≥ Ø‘√–«≥‘™¬å°ÿ≈ ·≈–§≥–339
4. °“√À“√âÕ¬≈–™àÕß«à“ߢÕßÕ“°“»
π”µ—«Õ¬à“ß∑’ˇµ√’¬¡‰¥â®“°À—«¢âÕ 1 ∑’褈Ҥ«“¡™◊Èπµà“ßÊ¡“„ à„π¿“™π–√Ÿª∑√ß°√–∫Õ°∑’Ë¡’ª√‘¡“µ√ 250 ≈∫.´¡.‚¥¬§àÕ¬Ê „ à®π‡µÁ¡¿“™π–·≈–‡µ‘¡πÈ”≈ß„π¿“™π–®π‡µÁ¡∫—π∑÷°ª√‘¡“µ√πÈ”∑’Ë„™â‰ª ·≈–∑”°“√∑¥≈Õ߇™àπ‡¥’¬«°—ππ’È°—∫µ—«Õ¬à“߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ ∑ÿ°Ê §à“§«“¡™◊Èπ∑’ˇµ√’¬¡‰«â„π¢âÕ 1 ·≈â«π”º≈∑’ˉ¥â§”π«≥À“√âÕ¬≈–™àÕß«à“ߢÕßÕ“°“» ·≈–∑”°“√∑¥≈Õß´È”∑’Ë·µà≈–§«“¡™◊Èπ 3§√—Èß
§”π«≥§à“√âÕ¬≈–™àÕß«à“ߢÕßÕ“°“»µ“¡ ¡°“√ (2)
ε = VOil
Vb
×100 (2)
‡¡◊ËÕε §◊Õ §à“ —¥ à«π™àÕß«à“ߢÕßÕ“°“», %V
oil§◊Õ ª√‘¡“µ√πÈ”¡—π, ≈∫.‡¡µ√
Vb
§◊Õ ª√‘¡“µ√¿“™π–, ≈∫.‡¡µ√
5. °“√∑¥≈ÕßÀ“§à“§«“¡√âÕπ®”‡æ“–
𔇻…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ ®“°¢âÕ 1 π”¡“À“πÈ”Àπ—°·Àâß ·≈–„ ൗ«Õ¬à“ß≈ß„π·§≈Õ√’¡‘‡µÕ√å∑’Ë∑√“∫πÈ”Àπ—°·πàπÕπ ·≈–„™âπÈ”°≈—ËπÕÿ≥À¿Ÿ¡‘‡√‘Ë¡µâπ 65oC πÈ”Àπ—°40 °√—¡ „ à≈߉ª„π·§≈Õ√’¡‘‡µÕ√å ªî¥Ω“ °«π„À⇢⓰—π„À⥒ —߇°µ§à“Õÿ≥À¿Ÿ¡‘∑’Ë®ÿ¥ ¡¥ÿ≈ ∫—π∑÷°º≈ ·≈–∑”°“√∑¥≈Õß´È”∑’Ë·µà≈–§«“¡™◊Èπ 3 §√—Èß
∑”°“√§”π«≥À“§à“§«“¡√âÕπ®”‡æ“–¥â«¬ ¡°“√∑’Ë (3)
cp = −[mccc (Teq − Tci ) + mwcw (Teq − Twi )]
mp (Teq − Tpi )(3)
‡¡◊ËÕ cp
§◊Õ §«“¡√âÕπ®”‡æ“–¢Õߢ⓫‡ª≈◊Õ°, kJ/kgoCcc
§◊Õ §à“§«“¡®ÿ§«“¡√âÕπ®”‡æ“–¢Õß·§≈Õ√’¡‘‡µÕ√å,kJ/kgoC
cw
§◊Õ §à“§«“¡®ÿ§«“¡√âÕπ®”‡æ“–¢ÕßπÈ”, kJ/kgoCm
c§◊Õ ¡«≈¢Õß·§≈Õ√’¡‘‡µÕ√å, °°.
mp§◊Õ ¡«≈¢Õß«— ¥ÿ, °°.
mw§◊Õ ¡«≈¢ÕßπÈ”, °°.
Teq
§◊Õ Õÿ≥À¿Ÿ¡‘∑’Ë ¿“«– ¡¥ÿ≈, oC
Tci
§◊Õ Õÿ≥À¿Ÿ¡‘¢Õß·§≈Õ√’¡‘‡µÕ√å∑’Ë ¿“«–‡√‘Ë¡µâπ,oC
Twi
§◊Õ Õÿ≥À¿Ÿ¡‘¢ÕßπÈ”∑’Ë ¿“«–‡√‘Ë¡µâπ, oCT
pi§◊Õ Õÿ≥À¿Ÿ¡‘¢Õß«— ¥ÿ∑’Ë ¿“«–‡√‘Ë¡µâπ, oC
6. °“√∑¥≈ÕßÕ∫·Àâß™—Èπ∫“ß
∑”°“√∑¥≈ÕßÕ∫·Àâßµ—«Õ¬à“ß∑’ˇµ√’¬¡§«“¡™◊Èπ‰«â„π¢âÕ 1 ¡“∑¥≈ÕßÕ∫·Àâߥ⫬Õÿª°√≥åÕ∫·Àâß∑’Ëæ—≤π“‚¥¬ ÿ¿«√√≥ ·≈–§≥– (2537) §«“¡™◊Èπ‡√‘Ë¡µâπ¢Õßµ—«Õ¬à“ßÕ¬Ÿà„π™à«ß 30-65% ¡“µ√∞“π·Àâß ”À√—∫‡»…¬“ß°âÕπ „™âÕÿ≥À¿Ÿ¡‘Õ∫·Àâß 100-130oC §«“¡‡√Á«≈¡ 1.5-2.5 ‡¡µ√/«‘π“∑’ ·≈– ”À√—∫¬“ß·ºàπ ¬“ß‡ âπ „™âÕÿ≥À¿Ÿ¡‘Õ∫·Àâß 40-70oC §«“¡‡√Á«≈¡ 1.5-2 ‡¡µ√/«‘π“∑’ ¢âÕ¡Ÿ≈∑’˵âÕß∫—π∑÷°§◊Õ πÈ”Àπ—°¢Õßµ—«Õ¬à“ßæ√âÕ¡µ–·°√ßÕ∫·Àâß Õÿ≥À¿Ÿ¡‘Õ“°“»√âÕπ Õÿ≥À¿Ÿ¡‘Õ“°“»·«¥≈âÕ¡°√–‡ª“–‡ªï¬° ·≈–°√–‡ª“–·Àâß ∫—π∑÷°º≈°“√∑¥≈Õß∑ÿ°Ê 5 π“∑’ „π™—Ë«‚¡ß·√° ∑ÿ° 10 π“∑’ „π§√÷Ëß™—Ë«‚¡ß∂—¥‰ª ·≈–∑ÿ°§√÷Ëß™—Ë«‚¡ß„π™—Ë«‚¡ßµàÕÊ ‰ª ®π°√–∑—Ë߉¥â§à“§«“¡™◊Èπ ÿ¥∑⓬ª√–¡“≥4% ¡“µ√∞“π·Àâß ®÷ßÀ¬ÿ¥°“√∑¥≈Õß
∑ƒ…Æ’
§«“¡™◊Èπ ¡¥ÿ≈ §◊Õ ‡¡◊ËÕπ”‡Õ“«— ¥ÿ∑’Ë¡’‚§√ß √â“ß¿“¬„π‡ªìπ√Ÿæ√ÿ𠇙àπ π”‡¡≈Á¥æ◊™‰ª«“߉«â„πÕ“°“» «— ¥ÿπ—ÈπÕ“®®–§“¬ (desorption) §«“¡™◊Èπ„Àâ°—∫Õ“°“» À√◊Õ¥Ÿ¥´—∫(adsorption) §«“¡™◊Èπ®“°Õ“°“» ·≈–‡¡◊ËÕ«“߉«â‡ªìπ‡«≈“π“πÊ «— ¥ÿπ’È®–¡’§«“¡™◊Èπ§ß∑’˧à“Àπ÷Ë߇√’¬°«à“§«“¡™◊Èπ ¡¥ÿ≈(Equilibrium Moisture Content, EMC) √Ÿª·∫∫ ¡°“√§«“¡™◊Èπ ¡¥ÿ≈∑’ˇ≈◊Õ°„™â‡æ◊ËÕÕ∏‘∫“¬§«“¡™◊Èπ ¡¥ÿ≈¢Õß«— ¥ÿ „π™à«ß§«“¡™◊Èπ —¡æ—∑∏å 0-100% ∑’ËÕÿ≥À¿Ÿ¡‘µà“ßÊ ”À√—∫„πß“π«‘®—¬π’È¡’¥—ßπ’È
¡°“√¢Õß Chung and Pfost (1967)
ln RH = (A
RTabs
)exp(−BMeq ) (4)
¡°“√¢Õß Henderson (1952)
1− RH = exp(−ATabs MeqB ) (5)
Songklanakarin J. Sci. Technol.
Vol. 29 (Suppl.2) May 2007: Grad. Res. 340
Parameters for the analysis of natural rubber drying
Tirawanichakul, S., et al.
¡°“√¢Õß Halsey (1948)
RH = exp(−A
RTabs
Meq )B(6)
‡¡◊ËÕ A, B, C, D §◊Õ §à“§ßµ—«„π ¡°“√ ´÷Ëߢ÷Èπ°—∫Õÿ≥À¿Ÿ¡‘·≈–™π‘¥¢Õß«— ¥ÿ
Meq
§◊Õ §«“¡™◊Èπ ¡¥ÿ≈, ‡»… à«π À√◊Õ% ¡“µ√∞“π·Àâß
R §◊Õ §à“§ßµ—«¢Õß°ä“´ ‡∑à“°—∫ 8.314kJ/kmol-K
RH §◊Õ §«“¡™◊Èπ —¡æ—∑∏å¢ÕßÕ“°“»,‡»… à«π
Tabs
§◊Õ Õÿ≥À¿Ÿ¡‘ —¡∫Ÿ√≥å, K
¡°“√Õ∫·Àâß §◊Õ ¡°“√∑’ËÕ“®‡¢’¬π¢÷Èπ‚¥¬„™â∑ƒ…Æ’À√◊Õº≈°“√∑¥≈ÕßÀ√◊Õ∑—Èß ÕßÕ¬à“ߪ√–°Õ∫°—π ‡æ◊ËÕπ”¡“„™â∑”π“¬Õ—µ√“°“√Õ∫·Àâßµ≈Õ¥®π∂÷ߺ≈¢Õßµ—«·ª√µà“ßÊ ∑’Ë¡’º≈µàÕ°“√Õ∫·Àâߺ≈‘µ¿—≥±åπ—ÈπÊ ¡°“√Õ∫·Àâß∑’Ëπ‘¬¡„™â°—π ‰¥â·°à ¡°“√Õ∫·Àâß∑“ß∑ƒ…Æ’ (Theoreticaldrying equation) ¡°“√Õ∫·Àâß°÷Ëß∑ƒ…Æ’ ·≈– ¡°“√Õ∫·Àâß·∫∫‡Õ¡æ‘√‘§—≈
¡°“√Õ∫·Àâß∑“ß∑ƒ…Æ’ ®–æ‘®“√≥“ Õß√Ÿª∑√ߧ◊Õæ‘®“√≥“‡ªìπ√Ÿª∑√ß°≈¡·≈–·ºàπ·∫π°«â“ß ‚¥¬®–„™â‡æ’¬ß “¡‡∑Õ¡·√°¢Õß ¡°“√°“√Õ∫·Àâß ¥—ßπ’È
√Ÿª∑√ß°≈¡
MR = 6π 2
exp−π 2 Dt
r02
+ 14
exp
−4π 2 Dtr0
2
+ 19
exp
−9π 2 Dtr0
2
(7)√Ÿª∑√ß·ºàπ·∫π°«â“ß
MR = 8π 2
exp−π 2 Dt
12
+ 19
exp
−9π 2 Dt12
+ 125
exp
−25π 2 Dt12
(8)‡¡◊ËÕ r
0§◊Õ √—»¡’¢Õ߬“ß∑¥≈Õß = 0.0025 ‡¡µ√
l §◊Õ §«“¡Àπ“§√÷ËßÀπ÷ËߢÕ߬“ß∑¥≈Õß =0.00325 ‡¡µ√
D §◊Õ §à“ —¡ª√– ‘∑∏‘Ï°“√·æ√ଗߺ≈, µ√.‡¡µ√/™¡.
MR §◊Õ Õ—µ√“ à«π§«“¡™◊Èπ, ‰√âÀπ૬ ‡¢’¬π‡ªì𧫓¡ —¡æ—π∏å√–À«à“ߧ«“¡™◊Èπ‰¥â«à“
MR =M − Meq
Min − Meq
‡¡◊ËÕ M §◊Õ §«“¡™◊Èπ„π°“√∑¥≈Õß, ‡»… à«π¡“µ√∞“π·Àâß
Min
§◊Õ §«“¡™◊Èπ‡√‘Ë¡µâπ, ‡»… à«π¡“µ√∞“π·ÀâßM
eq§◊Õ §«“¡™◊Èπ ¡¥ÿ≈, ‡»… à«π¡“µ√∞“π·Àâß
¡°“√Õ∫·Àâß°÷Ëß∑ƒ…Æ’ (Semi-theoretical dryingequation)
¡°“√∑’Ëπ‘¬¡„™â°—π¡’√Ÿª·∫∫¥—ßπ’È§à“ —¡ª√– ‘∑∏‘Ï°“√·æ√à (D) ·≈–§à“§ßµ—«¢Õß°“√Õ∫
·Àâß (k) ‡ªìπ§à“§ß∑’Ë¢Õß ¡°“√·µà≈– ¡°“√¥—ß°≈à“«®–‡ªìπ ¡∫—µ‘‡©æ“–¢Õߺ≈‘µ¿—≥±åÀπ÷ËßÊ ¿“¬„π™à«ß ¿“«–Õ“°“»Õ∫·Àâß∑’Ë∑”°“√∑¥≈Õ߇∑à“π—È𠧫“¡ —¡æ—π∏å¢Õß§à“§ß∑’ËÕ∫·Àâßπ’È¡—°π‘¬¡„™â ¡°“√Õ“√å√’‡π’¬ ‡™àπ‡¥’¬«°—∫§à“ —¡ª√– ‘∑∏‘Ï°“√·æ√ଗߺ≈ ¥—ßµàÕ‰ªπ’È
MR = exp(−kt)
‡¡◊ËÕ A ·≈– B §◊Õ §à“§ßµ—«¢Õß ¡°“√, ¢÷ÈπÕ¬Ÿà°—∫™π‘¥¢Õߺ≈‘µ¿—≥±å
k §◊Õ §à“§ßµ—«¢Õß ¡°“√, s-1
Tabs
§◊Õ Õÿ≥À¿Ÿ¡‘Õ∫·Àâß, K
¡°“√Õ∫·Àâ߇աæ‘√‘§—≈ (Empirical drying equa-tion)
¡°“√Õ∫·Àâ߇աæ‘√‘§—≈ §◊Õ ¡°“√∑’Ë √â“ß®“°¢âÕ¡Ÿ≈°“√∑¥≈Õß ”À√—∫º≈‘µ¿—≥±å „π™à«ßÕÿ≥À¿Ÿ¡‘™à«ß§«“¡™◊Èπ —¡æ—∑∏å ·≈–§«“¡‡√Á«¢ÕßÕ“°“»Õ∫·ÀâßÀπ÷ËßÊ æ∫«à“ “¡“√∂„™â∑”π“¬Õ—µ√“°“√Õ∫·Àâ߉¥â¥’ ·µà¡’¢âÕ®”°—¥„π‡ß◊ËÕπ‰¢°“√Õ∫·Àâß∑’˵âÕß°“√µâÕßµ√ß°—∫ ¿“«–°“√∑¥≈Õß
”À√—∫„πß“π«‘®—¬π’È ®“°º≈°“√∑¥≈ÕßÕ∫·Àâß™—Èπ∫“ß “¡“√∂π”¢âÕ¡Ÿ≈°“√∑¥≈Õ߉ª √â“ߧ«“¡ —¡æ—π∏å„π‡™‘ß§≥‘µ»“ µ√å„π√Ÿª·∫∫ ¡°“√Õ∫·Àâß°÷Ëß∑ƒ…Æ’ ·≈– ¡°“√Õ∫·Àâ߇աæ‘√‘§—≈
«. ߢ≈“π§√‘π∑√å «∑∑.
ªï∑’Ë 29 (©∫—∫摇»… 2) æ.§. 2550 : ∫—≥±‘µ»÷°…“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ”À√—∫°“√«‘‡§√“–Àå°“√Õ∫·Àâ߬“ß∏√√¡™“µ‘
ÿ¿«√√≥ Ø‘√–«≥‘™¬å°ÿ≈ ·≈–§≥–341
º≈°“√∑¥≈Õß·≈–«‘®“√≥å
1. °“√À“§«“¡™◊Èπ ¡¥ÿ≈·∫∫§“¬§«“¡™◊Èπ
®“°º≈°“√∑¥≈ÕßÀ“§«“¡™◊Èπ ¡¥ÿ≈¢Õ߇»…¬“ß°âÕπ„π™à«ßÕÿ≥À¿Ÿ¡‘ 30-60C ·≈–°“√‡¢’¬π‚ª√·°√¡«‘‡§√“–Àå ¡°“√∂¥∂Õ¬‚¥¬«‘∏’°”≈—ß ÕßπâÕ¬∑’Ë ÿ¥ ‚¥¬„™â√Ÿª·∫∫ ¡°“√§«“¡™◊Èπ ¡¥ÿ≈¢Õß Henderson (1952) ¡°“√Halsey (1948) ¡°“√¢Õß Chung ·≈– Pfost (1967)·≈– ¡°“√¥—¥·ª≈ߢÕß Kaleemullah (1952) º≈∑’ˉ¥âπ”· ¥ß‰«â„π√“¬ß“ππ’È ®–‡ª√’¬∫‡∑’¬∫√Ÿª·∫∫ ¡°“√§«“¡ ¡¥ÿ≈ 3 √Ÿª·∫∫ ¡°“√∑’Ë„°≈⇧’¬ß‡∑à“π—Èπ
®“°°“√∑¥≈Õ߇¡◊ËÕπ”¢âÕ¡Ÿ≈¡“À“§à“§ß∑’Ë„π ¡°“√µà“ßÊ ¥â«¬«‘∏’∑“ߧ≥‘µ»“ µ√å æ∫«à“ ·∫∫®”≈Õß∑“ߧ≥‘µ»“ µ√å¢Õß Henderson (1952) „Àâº≈°“√§”π«≥„°≈⇧’¬ß°—∫º≈°“√∑¥≈ÕߢÕ߇»…¬“ß°âÕπ ·≈–¬“߇ âπ¡“°∑’Ë ÿ¥ · ¥ß¥—ß Figure 1 ·≈– 2 ·≈–‰¥â ¡°“√· ¥ß§«“¡ —¡æ—π∏å√–À«à“ߧ«“¡™◊Èπ ¡¥ÿ≈ §«“¡™◊Èπ —¡æ—∑∏å·≈–Õÿ≥À¿Ÿ¡‘¥—ßπ’È
‡»…¬“ß°âÕπ
1− RH = exp(−0.002936 74 Tabs Meq0.775623 )
R2 = 0.8663 MRS = 0.0280
¬“߇ âπ
1− RH = exp(−0.069350 Tabs Meq0.736921 )
R2 = 0.8907 MRS = 0.0033
”À√—∫¬“ß·ºàπ ¡°“√·∫∫®”≈Õߧ«“¡™◊Èπ ¡¥ÿ≈∑“ߧ≥‘µ»“ µ√å¢Õß Halsey (1948) „Àâº≈°“√§”π«≥„°≈⇧’¬ß°—∫º≈°“√∑¥≈ÕߢÕß¡“°∑’Ë ÿ¥ · ¥ß¥—ß Figure 3 ·≈–‰¥â ¡°“√· ¥ß§«“¡ —¡æ—π∏å¢Õߧ«“¡™◊Èπ —¡æ—∑∏å¢ÕßÕ“°“»Õÿ≥À¿Ÿ¡‘·≈–§«“¡™◊Èπ ¡¥ÿ≈ ¥—ßπ’È
¬“ß·ºàπ
RH = exp(−11.08492
RTabs
)Meq−0.886330 )
R2 = 0.8827 MRS = 0.1027
‡¡◊ËÕ Tabs
§◊Õ Õÿ≥À¿Ÿ¡‘Õ“°“»Õ∫·Àâß, Kt §◊Õ √–¬–‡«≈“, ™—Ë«‚¡ßk, n §◊Õ §à“§ßµ—«MRS §◊Õ Mean residue square value
MRS =(MRpredicted,i − MRobserved,i )
2
i=1
N
∑N
2. §«“¡Àπ“·πàπª√“°Ø¢Õ߬“ß∏√√¡™“µ‘
®“°º≈°“√∑¥≈Õߧ«“¡Àπ“·πàπª√“°Ø ·≈–
Figure 1. Comparison of equilibrium moisture
content at relative humidity 10-95%
between experimental data and model
of crumb rubber at temperature 30oC
Figure 2. Comparison of equilibrium moisture
content at relative humidity 10-95%
between experimental data and model
of rubber stick at temperature 45oC
Songklanakarin J. Sci. Technol.
Vol. 29 (Suppl.2) May 2007: Grad. Res. 342
Parameters for the analysis of natural rubber drying
Tirawanichakul, S., et al.
«‘‡§√“–Àå ¡°“√∂¥∂Õ¬‚¥¬«‘∏’°”≈—ß ÕßπâÕ¬∑’Ë ÿ¥ “¡“√∂À“§«“¡ —¡æ—π∏å√–À«à“ߧ«“¡Àπ“·πàπª√“°Ø°—∫§«“¡™◊Èπ¢Õ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ‰¥â¥—ßπ’È
§«“¡™◊ÈπÕ¬Ÿà„π™à«ß 20-65% ¡“µ√∞“π·Àâßρ
‡»…¬“ß°âÕπ = 250.79+2.0892 M R2 = 0.9839 MRS = 0.0012
ρ¬“ß·ºàπ
= 274.20+2.6535 M R2 = 0.9262 MRS = 0.007
ρ¬“߇ âπ
= 256.48+2.5710 M R2 = 0.9637 MRS = 0.017
‡¡◊ËÕ ρ §◊Õ §«“¡Àπ“·πàπª√“°Ø¢Õß, °°./≈∫.‡¡µ√
M §◊Õ §«“¡™◊Èπ‡√‘Ë¡µâπ¢Õ߬“ß∏√√¡™“µ‘,% ¡“µ√∞“π·Àâß
æ∫«à“ §«“¡Àπ“·πàπª√“°Ø°—∫§«“¡™◊Èπ¢Õ߬“ß∏√√¡™“µ‘®–¡’§à“‡æ‘Ë¡¢÷Èπ„π≈—°…≥–‡™‘߇ âπ ÷Ëß¡’√Ÿª·∫∫ ¡°“√‡™àπ‡¥’¬«°—∫√Ÿª·∫∫ ¡°“√¢Õßß“π«‘®—¬∑’Ë¡’°“√»÷°…“¡“·≈â« (Wetchacama et al., 2000; ÿ¿«√√≥ ·≈–§≥–,2537; Õ√ÿ≥’ ·≈–§≥–, 2533)
3. ‡ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“»¢Õ߬“ß∏√√¡™“µ‘
µ“¡∑’ˉ¥â«‘‡§√“–Àå„πÀ—«¢âÕ 2 ‡ªìπ°“√æ‘®“√≥“ª√‘¡“µ√√«¡∑—ÈߢÕ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ ·≈–ª√‘¡“µ√¢ÕßÕ“°“»∑’Ë·∑√°µ—«Õ¬Ÿà ¥—ßπ—Èπ‡ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“»°Á®–·ª√º—π°—∫§«“¡™◊Èπ¢Õ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ â𠇙àπ°—π ®“°°“√«‘‡§√“–Àå ¡°“√∂¥∂Õ¬‡æ◊ËÕÀ“§«“¡ —¡æ—π∏å√–À«à“߇ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“»°—∫§«“¡™◊Èπ‡√‘Ë¡µâπ¢Õ߬“ß∏√√¡™“µ‘ ‰¥âº≈¥—ßπ’ȧ◊Õ
§«“¡™◊ÈπÕ¬Ÿà„π™à«ß 20-65% ¡“µ√∞“π·Àâßε
‡»…¬“ß°âÕπ = 100.40-0.3168 M R2 = 0.9819 MRS = 0.005
ε¬“ß·ºàπ
= 103.55-0.7097 M R2 = 0.9518 MRS = 0.007
ε¬“ß‡ âπ
= 93.953-0.3555 M R2 = 0.9197 MRS = 0.004
‡¡◊ËÕ ε §◊Õ §«“¡Àπ“·πàπª√“°Ø¢Õ߬“ß, °°./≈∫.‡¡µ√M §◊Õ §«“¡™◊Èπ‡√‘Ë¡µâπ¢Õ߬“ß∏√√¡™“µ‘,
% ¡“µ√∞“π·Àâß
®“°°“√»÷°…“ æ∫«à“ ‡¡◊ËÕ§«“¡™◊Èπ¢Õ߇»…¬“ß°âÕπ¬“ß·ºàπ ·≈–¬“߇ âπ ‡æ‘Ë¡¢÷È𠇪Õ√凴Áπµå™àÕß«à“ߢÕßÕ“°“»®–¡’§à“≈¥≈ß„π≈—°…≥–‡™‘߇ âπ · ¥ß¥—ß Figure 5 µ“¡≈”¥—∫ ´÷Ëß¡’√Ÿª·∫∫ ¡°“√‡™àπ‡¥’¬«°—∫√Ÿª·∫∫ ¡°“√¢Õßß“π«‘®—¬∑’Ë¡’°“√»÷°…“¡“·≈â« ( ÿ¿«√√≥ ·≈–§≥–, 2537;Õ√ÿ≥’ ·≈–§≥–, 2533)
4. §à“§«“¡√âÕπ®”‡æ“–¢Õ߬“ß∏√√¡™“µ‘
®“°°“√»÷°…“æ∫«à“ ‡¡◊ËÕ§«“¡™◊Èπ¢Õ߇»…¬“ß°âÕπ ¬“ß·ºàπ ¬“ß‡ âπ ·≈–¬“ß∂⫬ ‡æ‘Ë¡¢÷È𠧫“¡√âÕπ®”‡æ“–®–¡’§à“‡æ‘Ë¡¢÷Èπ„π≈—°…≥–‡™‘߇ âπ · ¥ß¥—ß Figure 6 ®“°°“√
Figure 3. Comparison of equilibrium moisture
content between experimental data and
expected data of rubber sheet at rela-
tive humidity of 10-95% and temper-
ature of 37.5oC
Figure 4. Comparison of apparent density of
natural rubber at various moisture
contents.
«. ߢ≈“π§√‘π∑√å «∑∑.
ªï∑’Ë 29 (©∫—∫摇»… 2) æ.§. 2550 : ∫—≥±‘µ»÷°…“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ”À√—∫°“√«‘‡§√“–Àå°“√Õ∫·Àâ߬“ß∏√√¡™“µ‘
ÿ¿«√√≥ Ø‘√–«≥‘™¬å°ÿ≈ ·≈–§≥–343
«‘‡§√“–Àå ¡°“√∂¥∂Õ¬‡æ◊ËÕÀ“§«“¡ —¡æ—π∏å√–À«à“ߧ«“¡√âÕπ®”‡æ“–°—∫§«“¡™◊Èπ‡√‘Ë¡µâπ¢Õ߬“ß∏√√¡™“µ‘ ‰¥âº≈¥—ßπ’ȧ◊Õ
§«“¡™◊ÈπÕ¬Ÿà„π™à«ß 20-65% ¡“µ√∞“π·Àâßcp‡»…¬“ß°âÕπ
= 3.3808+0.0993M R2 = 0.9633 MRS = 0.009
cp¬“ß·ºàπ
= 0.3905+0.0570M R2 = 0.9585 MRS = 0.015
cp¬“߇ âπ
= 1.9500+0.0171M R2 = 0.8153 MRS = 0.004
‡¡◊ËÕ cp
§◊Õ §«“¡√âÕπ®”‡æ“–¢Õ߬“ß, kJ/kgoC
M §◊Õ §«“¡™◊Èπ‡√‘Ë¡µâπ¢Õ߬“ß∏√√¡™“µ‘,% ¡“µ√∞“π·Àâß
´÷Ëß ¡°“√§à“§«“¡√âÕπ®”‡æ“–π’È ®–™à«¬„Àâ∑√“∫∂÷ߧ«“¡ “¡“√∂„π°“√®ÿ§«“¡√âÕπ¢Õ߬“ß∏√√¡™“µ‘∑’褈Ҥ«“¡™◊Èπµà“ßÊ ·≈–¡’ª√–‚¬™πåµàÕ°“√«‘‡§√“–Àå∂÷ß°√–∫«π°“√∂à“¬‚Õ𧫓¡√âÕπ„À⬓ß∏√√¡™“µ‘ ´÷Ëß¡’√Ÿª·∫∫ ¡°“√‡™àπ‡¥’¬«°—∫√Ÿª·∫∫ ¡°“√¢Õßß“π«‘®—¬∑’Ë¡’°“√»÷°…“¡“·≈â«(Wetchacama et al., 2000; ÿ¿«√√≥ ·≈–§≥–, 2537;Õ√ÿ≥’ ·≈–§≥–, 2533)
5. ¡°“√Õ∫·Àâß
®“°°“√∑¥≈ÕßÕ∫·Àâß™—Èπ∫“ߢÕ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ „π™à«ß§«“¡™◊Èπ‡√‘Ë¡µâπ 30-65% ¡“µ√∞“π·Àâß ”À√—∫‡»…¬“ß°âÕπ „™âÕÿ≥À¿Ÿ¡‘Õ∫·Àâß 100-130C§«“¡‡√Á«≈¡ 1.5-2.5 ‡¡µ√/«‘π“∑’ ·≈– ”À√—∫¬“ß·ºàπ ¬“ß‡ âπ „™âÕÿ≥À¿Ÿ¡‘Õ∫·Àâß 40-70C §«“¡‡√Á«≈¡ 1.5-2 ‡¡µ√/«‘π“∑’ æ∫«à“ §«“¡™◊Èπ≈¥≈߇¡◊ËÕ‡«≈“°“√Õ∫·Àâ߇æ‘Ë¡¢÷Èπ‡¡◊ËÕπ”¡“§”π«≥À“Õ—µ√“ à«π§«“¡™◊Èπ “¡“√∂· ¥ß§«“¡ —¡æ—π∏å√–À«à“ßÕ—µ√“ à«π§«“¡™◊Èπ°—∫‡«≈“ ‡¡◊ËÕ«‘‡§√“–À姫“¡ —¡æ—π∏å√–À«à“ßÕ—µ√“ à«π§«“¡™◊Èπ°—∫‡«≈“ æ∫«à“√Ÿª·∫∫ ¡°“√‡Õ¡æ‘√‘§—≈ “¡“√∂Õ∏‘∫“¬º≈°“√∑¥≈Õ߉¥â¥’∑’Ë ÿ¥
”À√—∫‡»…¬“ß°âÕπ ¡°“√¥—¥·ª≈ߢÕß Hendersonand Pabis (1961) · ¥ß¥—ß Figure 7 “¡“√∂Õ∏‘∫“¬º≈°“√∑¥≈Õ߉¥â¥’ ¥—ß ¡°“√
MR = a exp(−kt)
‡¡◊ËÕ k = 0.0021T2 - 0.4504T + 25.489R2 = 0.9606
a = -0.0001T2 + 0.0204T + 0.0197R2 = 0.9583
MRS = 1.22
”À√—∫¬“ß·ºàπ ·≈–¬“߇ âπ ¡°“√¢Õß Page(1949) “¡“√∂Õ∏‘∫“¬º≈°“√∑¥≈Õ߉¥â¥’· ¥ß¥—ß Figure 8·≈– 9 ·≈–¥—ß ¡°“√
MR = exp(−ktn )
Figure 5. Comparison of percentage of void
fraction in the bed of natural rubber at
various moisture contents.
Figure 6. Comparison of specific heat of natural
rubber at various moisture contents
Songklanakarin J. Sci. Technol.
Vol. 29 (Suppl.2) May 2007: Grad. Res. 344
Parameters for the analysis of natural rubber drying
Tirawanichakul, S., et al.
”À√—∫¬“ß·ºàπk = -0.00563T + 2.17806 R2 = 0.9997n = 0.00384T - 1.00227 R2 = 0.9971MRS = 0.877
”À√—∫¬“߇ âπk = -4.499x10-5T2 + 0.0345T-6.3161
R2 = 0.9967n = -8.848x10-5T2 + 0.0606T-9.9479
R2 = 0.9986MRS = 0.737
Figure 7. Relationship between moisture ratio and drying time of crumb rubber at initial
moisture content of 30-65% dry-basis for drying temperatures of 100-130oC.
‡¡◊ËÕ T §◊Õ Õÿ≥À¿Ÿ¡‘Õ“°“»Õ∫·Àâß, Ct §◊Õ √–¬–‡«≈“, ™—Ë«‚¡ßk,n §◊Õ §à“§ßµ—«
6. §à“ —¡ª√– ‘∑∏‘Ï°“√·æ√৫“¡™◊Èπ
®“°°“√∑¥≈ÕßÕ∫·Àâß™—Èπ∫“ߢÕ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ „π™à«ß§«“¡™◊Èπ‡√‘Ë¡µâπ 30-65% ¡“µ√∞“π·Àâß ”À√—∫‡»…¬“ß°âÕπ „™âÕÿ≥À¿Ÿ¡‘Õ∫·Àâß 100-130C§«“¡‡√Á«≈¡ 1.5-2.5 ‡¡µ√/«‘π“∑’ ·≈– ”À√—∫¬“ß·ºàπ ¬“ß‡ âπ „™âÕÿ≥À¿Ÿ¡‘Õ∫·Àâß 40-70C §«“¡‡√Á«≈¡ 1.5-2 ‡¡µ√/«‘π“∑’ ‚¥¬°“√„™â√Ÿª·∫∫ ¡°“√Õ“√å‡√‡π’¬ ‰¥âº≈¥—ßπ’È
Figure 8. Relationship between moisture ratio
and drying time of rubber sheet at initial
moisture content of 30-65% dry-basis
for drying temperatures of 50 and 70oC.
Figure 9. Relationship between moisture ratio
and drying time of rubber stick at initial
moisture content of 30-65% dry-basis
for drying temperatures of 50-70oC.
«. ߢ≈“π§√‘π∑√å «∑∑.
ªï∑’Ë 29 (©∫—∫摇»… 2) æ.§. 2550 : ∫—≥±‘µ»÷°…“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ ”À√—∫°“√«‘‡§√“–Àå°“√Õ∫·Àâ߬“ß∏√√¡™“µ‘
ÿ¿«√√≥ Ø‘√–«≥‘™¬å°ÿ≈ ·≈–§≥–345
‡»…¬“ß°âÕπ
D = 41.3857exp−6158.473T + 273.15
R2 = 0.971 MRS = 0.037
¬“ß·ºàπ
D = 4 ×10−5 exp−1192.368T + 273.15
R2 = 0.923 MRS = 0.044
¬“߇ âπ
D = 52.96805exp−6078.694T + 273.15
R2 = 0.913 MRS = 0.015
‚¥¬§à“ —¡ª√– ‘∑∏‘Ï°“√·æ√ଗߺ≈ (D) ¢Õ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ â𠇪ìπøíß°å™—π°—∫Õÿ≥À¿Ÿ¡‘ ·≈–¡’§à“‡æ‘Ë¡¢÷Èπ‡ªìπ·∫∫‡Õ°´å‚ª‡ππ‡™’¬≈
√ÿªº≈°“√∑¥≈Õß
1. §«“¡™◊Èπ ¡¥ÿ≈¢Õ߇»…¬“ß°âÕπ ¬“ß·ºàπ ·≈–¬“߇ âπ ®–¡’§à“‡æ‘Ë¡¢÷Èπ ‡¡◊ËÕ§«“¡™◊Èπ —¡æ—∑∏å‡æ‘Ë¡¢÷Èπ„π™à«ßÕÿ≥À¿Ÿ¡‘ 35-60C ‡¡◊ËÕπ”¡“«‘‡§√“–ÀåÀ“√Ÿª·∫∫ ¡°“√∑’ˇÀ¡“– ¡ æ∫«à“ ¡°“√¢Õß Henderson (1952) Õ∏‘∫“¬º≈°“√∑¥≈ÕߢÕ߇»…¬“ß°âÕπ·≈–¬“߇ âπ ‰¥â¥’∑’Ë ÿ¥ à«π¬“ß·ºàπ ¡°“√¢Õß Halsey (1948) “¡“√∂Õ∏‘∫“¬º≈°“√∑¥≈Õ߉¥â¥’∑’Ë ÿ¥
2. §«“¡Àπ“·πàπª√“°Ø¢Õ߬“ßµ—«Õ¬à“ß∑—Èß 3 ™π‘¥¡’§à“‡æ‘Ë¡¢÷Èπµ“¡§«“¡™◊Èπ‡√‘Ë¡µâπ „π™à«ß§«“¡™◊Èπ 20-65%¡“µ√∞“π·Àâß ¡°“√§«“¡ —¡æ—π∏å°—∫§«“¡™◊Èπ‡ªìπ≈—°…≥–‡™‘߇ âπ
3. ‡ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“»¢Õ߬“ßµ—«Õ¬à“ß∑—Èß3 ™π‘¥ ¡’§à“≈¥≈ßµ“¡ª√‘¡“≥§«“¡™◊Èπ‡√‘Ë¡µâπ „π™à«ß§«“¡™◊Èπ 20-65% ¡“µ√∞“π·Àâß ¡°“√§«“¡ —¡æ—π∏å°—∫§«“¡™◊Èπ‡ªìπ≈—°…≥–‡™‘߇ âπ
4. §«“¡√âÕπ®”‡æ“–¢Õ߬“ßµ—«Õ¬à“ß∑—Èß 3 ™π‘¥ ¡’
§à“‡æ‘Ë¡¢÷Èπµ“¡§«“¡™◊Èπ‡√‘Ë¡µâπ „π™à«ß§«“¡™◊Èπ 20-65%¡“µ√∞“π·Àâß ¡°“√§«“¡ —¡æ—π∏å°—∫§«“¡™◊Èπ‡ªìπ≈—°…≥–‡™‘߇ âπ
5. Õ—µ√“ à«π§«“¡™◊Èπ ”À√—∫‡»…¬“ß°âÕπ ®–¡’§à“≈¥≈߇¡◊ËÕ‡«≈“·≈–Õÿ≥À¿Ÿ¡‘¢Õß°“√Õ∫·Àâ߇æ‘Ë¡¢÷Èπ √Ÿª·∫∫ ¡°“√Õ∫·Àâß™—Èπ∫“ß∑’Ëπ”¡“„™â„π°“√Õ∏‘∫“¬º≈°“√∑¥≈Õß· ¥ß„π√Ÿª·∫∫¢Õß ¡°“√‡Õ¡æ‘√‘§—≈ ·≈– ¡°“√°÷Ëß∑ƒ…Æ’
6. §à“ —¡ª√– ‘∑∏‘Ï°“√·æ√৫“¡™◊Èπ ”À√—∫‡»…¬“ß°âÕπ ¬“ß·ºàπ ¬“ß‡ âπ · ¥ß„π√Ÿª·∫∫ ¡°“√Õ“√å‡√‡π’¬ ·≈–‡ªìπ§à“ —¡ª√– ‘∑∏‘Ï°“√·æ√ଗߺ≈®–‡ªìπøíß°å™—π°—∫Õÿ≥À¿Ÿ¡‘ ·≈–¡’§à“‡æ‘Ë¡¢÷Èπ‡ªìπ·∫∫‡Õ°´å‚ª‡ππ‡™’¬≈
ß“π«‘®—¬π’ȇªìπ°“√»÷°…“À“æ“√“¡‘‡µÕ√å∑’Ë®”‡ªìπ„π°“√«‘‡§√“–Àå°“√Õ∫·ÀâߢÕ߬“ß∏√√¡™“µ‘ ¿“¬„µâ‡ß◊ËÕπ‰¢°“√Õ∫·Àâß∑’ËÕÿ≥À¿Ÿ¡‘µà“ßÊ º≈°“√∑¥≈Õß·≈– ¡°“√·∫∫®”≈Õß∑“ߧ≥‘µ»“ µ√å “¡“√∂𔉪„™âª√–‚¬™πå„π°“√∑”𓬰“√Õ∫·ÀâߢÕ߬“ߥ‘∫∏√√¡™“µ‘ ‰¥â·°à ‡»…¬“ß°âÕπ ¬“ß·ºàπ¥‘∫ ¬“ß·ºàπ√¡§«—𠇪ìπµâπ º≈°“√∑¥≈Õ߉¥â∑”°“√∑¥≈Õߧ√Õ∫§≈ÿ¡™à«ß§«“¡™◊Èπ‡√‘Ë¡µâπ¢Õ߬“ß∏√√¡™“µ‘„π™à«ß∑’Ë¡’°“√„™âß“π®√‘ß (§«“¡™◊Èπ‡√‘Ë¡µâπ 20-65% ¡“µ√∞“π·Àâß) ·≈–Õÿ≥À¿Ÿ¡‘∑’Ë„™â„π°“√Õ∫·Àâߧ√Õ∫§≈ÿ¡∑—È߬“ß·ºà𵓰·Àâß (Õÿ≥À¿Ÿ¡‘µË”°«à“ 70oC) ¬“ß·ºàπ√¡§«—π (Õÿ≥À¿Ÿ¡‘40-60oC) ·≈–°“√Õ∫·Àâ߬“ß·∑àß¡“µ√∞“π‡Õ ∑’Õ“√å(Õÿ≥À¿Ÿ¡‘ Ÿß°«à“ 100oC) ´÷Ëß®—¥‡ªìπ ‘π§â“ÕÕ°∑’Ë ”§—≠¢Õߪ√–‡∑»‰∑¬Õ¬à“ßÀπ÷Ëߥ⫬ æ∫«à“ æ“√“¡‘‡µÕ√åµà“ßÊ ‰¥â·°à§à“§«“¡™◊Èπ ¡¥ÿ≈ §à“§«“¡Àπ“·πàπª√“°Ø ‡ªÕ√凴Áπµå™àÕß«à“ߢÕßÕ“°“» §à“§«“¡√âÕπ®”‡æ“– ¡°“√Õ∫·Àâß™—Èπ∫“ß ”À√—∫¬“ß·µà≈–™π‘¥ “¡“√∂𔉪„™â‡ªìπ¢âÕ¡Ÿ≈æ◊Èπ∞“π„π°“√æ—≤π“·≈–®”≈Õß√–∫∫Õ∫·ÀâߢÕ߬“ß·µà≈–™π‘¥ ‡æ◊ËÕ„À≥â·π«∑“ß°“√Õ∫·Àâß∑’ˇÀ¡“– ¡¿“¬„µâ ¿“«–¢ÕßÕ“°“»·«¥≈âÕ¡Àπ÷ËßÊ ‚¥¬∑“ߧ≥–ºŸâ«‘®—¬‡Õ߉¥â¡’‚§√ß°“√«‘®—¬∑’˵àÕ‡π◊ËÕß®“°ß“π™ÿ¥π’ȧ◊Õ °“√»÷°…“§«“¡‡ªìπ‰ª‰¥â¢Õß°“√Õ∫·Àâ߬“ß·ºàπ¥â«¬≈¡√âÕπ√à«¡°—∫Õ‘πø√“‡√¥ (ß∫ª√–¡“≥·ºàπ¥‘π ªï æ.». 2549) ·≈–‚§√ß°“√«‘®—¬ °“√Õ∫·Àâß∑’ˇÀ¡“– ¡¢ÕßÕÿµ “À°√√¡º≈‘µ¬“ß·∑àß‡Õ ∑’Õ“√å ( ”π—°ß“π°Õß∑ÿπ«‘®—¬·Ààß™“µ‘ ( °«.) ªï æ.». 2548-2549) ´÷Ëß∑—Èß Õß‚§√ß°“√«‘®—¬π’È®”‡ªìπµâÕßÕ“»—¬æ“√“¡‘‡µÕ√å‡À≈à“π’È„π°“√À“·π«∑“ß°“√Õ∫·Àâß∑’ˇÀ¡“– ¡µàÕ‰ª
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Parameters for the analysis of natural rubber drying
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°‘µµ‘°√√¡ª√–°“»
„π°“√«‘®—¬§√—Èßπ’ȉ¥â√—∫∑ÿπÕÿ¥Àπÿπ°“√«‘®—¬·≈–«‘∑¬“-π‘æπ∏å√–¥—∫∫—≥±‘µ»÷°…“ ¡À“«‘∑¬“≈—¬ ߢ≈“π§√‘π∑√åª√–®”ªïß∫ª√–¡“≥ 2548 ·≈–∑ÿπ®“° ”π—°ß“π π—∫ πÿπ°Õß∑ÿπ«‘®—¬ ª√–®”ªï 2548 µ≈Õ¥®π‡§√◊ËÕß¡◊Õ·≈–Õÿª°√≥å„π°“√∑¥≈Õßµà“ßÊ ¢Õß¿“§«‘™“«‘»«°√√¡‡§¡’ ¿“§«‘™“«‘»«°√√¡‡§√◊ËÕß°≈ ·≈–¿“§«‘™“øî ‘° å ¡À“«‘∑¬“≈—¬ ߢ≈“-π§√‘π∑√å «‘∑¬“‡¢µÀ“¥„À≠à ·≈–∫ÿ§≈“°√∑à“πµà“ßÊ ∑’ˇ°’ˬ«¢âÕß ‰¥â·°à ºŸâ™à«¬»“ µ√“®“√¬å‰æ‚√®πå §’√’√—µπå ”π—°ª√– “πß“π™ÿ¥‚§√ß°“√«‘®—¬ "°“√æ—≤π“Õÿµ “À°√√¡¬“ßæ“√“" §ÿ≥ ¡æ√ æ߻墮√ ∑à“πºŸâ®—¥°“√∫√‘…—∑Õ—≈≈“¬¥å‡∑§‡ÕÁ𮑇π’¬√‘ß ®”°—¥ ‡¢µ∫÷ß°ÿà¡ °√ÿ߇∑æ¡À“π§√ ·≈–§ÿ≥∑πß»—°¥å ‡ π“ߧπ‘°√ ∑à“πºŸâ®—¥°“√‚√ßß“π¬“ß·∑àß∫√‘…—∑‡´“∑å·≈π¥å√’´Õ√å´ ®”°—¥ “¢“∂È”æ√√≥√“¬ ®—ßÀ«—¥π§√»√’-∏√√¡√“™ ®π∑”„Àâ°“√¥”‡π‘πß“π«‘®—¬§√—Èßπ’È ”‡√Á®≈ÿ≈à«ß‰ª‰¥â¥â«¬¥’ §≥–ºŸâ«‘®—¬¢Õ¢Õ∫§ÿ≥¡“ ≥ ∑’Ëπ’È
‡Õ° “√Õâ“ßÕ‘ß
°√¡«‘™“°“√‡°…µ√. 2547. ∂“π°“√≥å°“√º≈‘µ·≈–°“√µ≈“¥¬“ß. ‡Õ° “√«‘™“°“√¬“ßæ“√“ ª√–®”ªï 2547 ‡≈à¡∑’Ë20. °√¡«‘™“°“√‡°…µ√ °√–∑√«ß‡°…µ√·≈– À°√≥å.
∏π‘µ «— ¥‘χ «’ ¡™“µ‘ ‚ ¿≥√≥ƒ∑∏‘Ï Õ¥‘»—°¥‘Ï π“∂°√≥°ÿ≈·≈–‡ªïò¬¡»‘≈ªá ∑Õß∑‘æ¬å. 2542. °“√Õ∫·Àâ߇¡≈Á¥„π¡–¡à«ßÀ‘¡æ“πµå¥â«¬‡§√◊ËÕßÕ∫·Àâß·∫∫À¡ÿπ. «.‡°…µ√-»“ µ√å («‘∑¬.). 33: 159-169.
¡™“µ‘ ‚ ¿≥√≥ƒ∑∏‘Ï. 2540. °“√Õ∫·Àâ߇¡≈Á¥æ◊™·≈–Õ“À“√∫“ߪ√–‡¿∑. §≥–æ≈—ßß“π·≈–«— ¥ÿ ¡À“«‘∑¬“≈—¬‡∑§‚π‚≈¬’æ√–®Õ¡‡°≈â“∏π∫ÿ√’.
ÿ¿«√√≥ Ø‘√–«≥‘™¬å°ÿ≈ ·≈–¬ÿ∑∏π“ Ø‘√–«≥‘™¬å°ÿ≈. 2537.Õÿª°√≥åÕ∫·Àâ߇¡≈Á¥æ◊™™—Èπ∫“ß: æ“√“¡‘‡µÕ√å¢Õß°“√Õ∫·Àâß™—Èπ∫“߇π◊ÈÕ„π‡¡≈Á¥¡–¡à«ßÀ‘¡æ“πµå. «. ߢ≈“-π§√‘π∑√å. «∑∑. 16(4): 381-392.
Õ√ÿ≥’ ºÿ¥ºàÕß ¡™“µ‘ ‚ ¿≥√≥ƒ∑∏‘Ï ·≈–«“√ÿ≥’ ‡µ’¬. 2533.°“√»÷°…“§à“æ“√“¡‘‡µÕ√å ”À√—∫«‘‡§√“–Àå°“√Õ∫·Àâ߇¡≈Á¥¢â“«‚æ¥. «‘»«°√√¡ “√. 4: 95-101.
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