Engineering, 2015, 7, 717-732
Published Online October 2015 in SciRes. http://www.scirp.org/journal/eng
http://dx.doi.org/10.4236/eng.2015.710063
How to cite this paper: Matee, V.E. and Manyele, S.V. (2015) Analysis of Temperature Profiles and Cycle Time in a
Large-Scale Medical Waste Incinerator. Engineering, 7, 717-732. http://dx.doi.org/10.4236/eng.2015.710063
Analysis of Temperature Profiles and Cycle
Time in a Large-Scale Medical Waste
Incinerator
Veilla E. Matee, Samwel V. Manyele
Department of Chemical and Mining Engineering, University of Dar es Salaam, Dar es Salaam, Tanzania
Email: veilla.elisante@mnh.or.tz , smanyele@udsm.ac.tz
Received 29 May 2015; accepted 27 October 2015; published 30 October 2015
Copyright © 2015 by authors and Scientific Research Publishing Inc.
This work is licensed under the Creative Commons Attribution International License (CC BY).
http://creativecommons.org/licenses/by/4.0/
Abstract
Temperature profiles and cycle times in a large-scale medical waste incinerator installed in a re-
ferral hospital were used to assess the performance and functionality of incinerator. The study
was conducted using data collected from 8 cycles per days for 67 days. For proper combustion and
destruction of toxic components in the primary chamber and destruction of pollutants and toxic
components in the flue gas, it is desired to reach the maximum temperature in the chambers faster
and maintain this maximum temperature for an extended time interval. The primary and secon-
dary temperatures T1 and T2, respectively, were recorded at an interval of one minute for different
cycles. Different amounts of wastes with varying proportions of sharps and other wastes were
loaded into the incinerator and temperature profiles recorded. The analysis shows that the incin-
erator works at primary temperature less than the required recommended by manufacturer while
the secondary chamber operates between 600 and above 950˚C, although higher temperatures up
to 1020˚C were observed. The average load preparation time was observed to be 14.6 minutes,
while the chamber preheating time before daily initial loading was 25.45 minutes. Both tempera-
ture profiles were observed to have similar shapes for all combustion cycles studied, except when
incinerator malfunctioning occurred. The average cycle time was established to be 32.7 minutes
and 28.97 minutes based on time to drop to 550˚C after the maximum temperature and loading
time intervals, respectively, although longer cycle times were observed. Temperature drop in both
combustion chambers as a result of waste charging was observed in the interval of 5 minutes. The
chamber heating rate was observed to decrease exponentially with time during both preheating
and incineration operation.
Keywords
Medical Waste Management, Infectious Waste, Pathological Waste, Sharps Waste, Incineration,