| Abstrak/Abstract |
The development of Pneumatic Conveying Dryer (PCD) or flash dryer for drying aut high water- containing flour materials can be Implemented by continuously recycling the materials. The recirculation process may increase the residence time of the materials, and reduce the length of drying pipes (the dryer's height) on PCD machine. In this research, the PCD machine had been developed into Pneumatic Conveying Recirculated Dryer (PCRD) with LPG fuel. The objective of this research was to evaluate the performance of PCRD machine in order to determine effects of drying process variable variations on values of Effective Heat Efficiency (EHE), Heat Utilization Factor (HUF), and Coefficient of Performance (COP) using mathematical and statistical analysis. The mathematical analysis result from variation of drying process variable obtains HUF value of 70.383%, EHE at 78.819% and COP at 29.617%. The mathematical analysis result suggests that HUF value is greater than COP's. It shows that the use of heat in the dryer is considerably effective. The smaller the COP value, the better the dryer's performance. The results of statistical analysis with one-way anova test show that variable variations significantly affecting EHE are drying air temperature (Tu3), the length of the recirculation or drying pipes (L,), the diameter of outlet pipe on recirculation cyclone (DAab), and the blower's air velocity on recirculation cyclone (Vucrb). Meanwhile, the variable variations significantly affecting HUF and COP are Vu, L, and DAct, It demonstrates that PCRD machine has a good performance, making it suitable for use in the drying process of flour materials with high moisture content. |
