Dry dechlorination of solid-derived fuels obtained from food waste and polyvinyl chloride

Abstract

Solid-recovered fuels (SRFs) with low chlorine (Cl) contents are urgently needed, particularly considering the limited availability of energy resources globally. Two main sources of chlorinated pollution in municipal solid wastes, namely food waste and polyvinyl chloride (PVC), were used as raw materials for SRF production. These materials were dechlorinated using alkaline adsorbents (calcium hydroxide (Ca(OH)2) and sodium bicarbonate (NaHCO3)), yielding five sample SRFs. The SRFs had low heating values (LHVs) of 14.10–15.12 MJ/kg. The alkaline adsorbents were introduced during dry dechlorination, which increased the LHVs by 8.4 MJ/g. Approximately 50 % of the total Cl content was transformed into the liquid and gaseous phases after incineration of the SRF. The PVC content was increased to increase the amount of gaseous Cl produced. Conversely, the yields of liquid and solid Cl increased when the FW content was increased. Among alkaline adsorbents, Ca(OH)2 exhibited better adsorption performance than NaHCO3. Upon mixing ~15 wt% of Ca(OH)2 with the SRFs, the highest Cl removal efficiency (77 %) in the gaseous phase was achieved. Over 90 % of the total Cl content was converted into solid-phase calcium chloride and sodium chloride by the alkaline adsorbents. The total cost of the SRF was US$85.48/t, of which labor and electricity costs accounted for 50 % and 25 %, respectively.