IJE TRANSACTIONS B: Applications Vol. 24, No. 2 (July 2011) 119-126   

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I. Hamawand*

Department of Chemical Engineering, Koya University, Koya 47015, Erbil, Iraq


*Corresponding Author

( Received: October 11, 2010 – Accepted in Revised Form: April 23, 2011 )

Abstract    It is very important in the design of a drying system is to evaluate sticking behaviour of the materials goes under drying. A new approach to the sticking issue is applied in this study by carrying out a sticking test for the liquid associated with the materials under study. It was found that the liquid bridge is responsible of the initial sticking of the materials to the contact surface and the colloidal material in this liquid is eventually responsible of building a sticky solid bridge during drying. The glass transition temperature for the Brewers Spent Grain (BSG) particles and the colloidal solution that expelled from these particles is tested using Differential Scanning Calorimetric (DSC). However that the chopped BSG particles showed no glass transition temperature there was a marked amount of it that sticked to the rotary drum dryer and the sample holders during drying. The sticking behaviour may be regarded to the colloidal particles in the liquid associated with the grain. The colloidal particles in this liquid is filtered and concentrated through evaporation and then tested by the (DSC) where it showed a glass transition temperature at (-23) and (-33) C. In addition, the associated liquid has a honey shape and a sticky touch when concentrated. These two properties are an indication that this colloidal material may be responsible of sticking the BSG to the steel surfaces during drying.


Keywords    colloidal particles, sticking, liquid bridge, rotary drum, superheated steam drying.


چکیده    چكيده در طراحي يك سيستم خشك كن، ارزيابي رفتار چسبندگي موادي كه خشك مي شوند پارامتر مهمي است . در اين مطالعه با انجام تست چسبندگي براي مايع مربوط با مواد مورد بررسي، راهكار نويني در ارتباط با اين موضوع به كار گرفته شده است . بررسي ها نشان داده است كه پل مايع، عامل چسبندگي اوليه مواد به سطح تماس بوده و همچنين ماده كلوئيدي موجود در اين مايع عامل ايجاد يك پل جامد چسبنده در طي فرآيند خشك كردن مي باشد. دماي گذار شيشه اي براي ذرات دانه اي مورد استفاده در آبجو سازي(BSG) و محلول كلوئيدي حاصل از آن با استفاده از آزمايش هاي اختلاف كالريمتري (DSC) مورد بررسي قرار گرفته است. اگر چه ذرات خرد شده(BSG) دماي گذار شيشه اي را نشان نداده اند اما تعداد قابل ملاحظه اي از آن ها به خشك كن دوار و نگه دارنده هاي نمونه در حين خشك كردن چسبيدند. ذرات كلوئيدي در پل مايع فيلتر و با استفاده از روش تبخير تغليظ شد. همچنين با بهره گيري از آناليز (DSD) دماي گذار شيشه اي در دماهاي oC 23- و 33- نشان داده شده است. علاوه بر آن مايع آماده شده با روش بالا قوام و چسبندگي در حين تغليظ از خود نشان داد. اين دو پارامترمويد اين مطلب بوده كه مواد كلوئيدي عامل اصلي چسبندگي ذرات BSG به سطوح استيل در حين خشك كردن مي باشند


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