This paper presents findings on heat recovered from a batch-operated double-chamber healthcare waste incineration plant using two double-pipe heat exchangers (DPHEs) in series. The research was carried out at Tumbi Regional Referral Hospital (TRRH) located in Coast Region, Tanzania. The chambers were fitted with diesel burners (model Riello G20). The air blower (1.1 kW) was used to supply air in the chambers. The inlet and outlet fluid temperatures for both flue gas (FG) and cooling water (CW) across the heat exchangers (HXs) were recorded for 3-hour incineration cycles. For each cycle, set values of CW flow rates, waste load (of known composition) were used. One cycle was completed per day for 12 cycles. The total waste loaded ranged between 110 and 183 kg per cycle, while the ash collected after cooling ranged from 8.0 to 21.8% by weight. The weight reduction ranged from 84.6 to 91.3%. The FG temperature at the four measurement locations increased initially to the maximum within 40 minutes before decreasing again. The CW temperature increased from room temperature to a maximum of 75?C (for a volume of 1,500 L). The maximum total heat energy recovered per cycle was 44.3 MW. The HX1 (with countercurrent flow arrangement) recovered more heat energy than the HX2 (with co-current flow) similar to literature reports. It was concluded that heat recovery from the incineration of HCW is significant. The hospitals are recommended to adopt heat recovery practices from the incineration of HCW.
Keywords: Waste composition, double pipe heat exchanger, healthcare waste incineration, flue gas, temperature profiles, cooling water flow rate, temperature drop and gain.