Energy Balance, Capacity Sizing Verification, and Dioxin Risk Screening of a Titanium Structured Waste-to-Energy Incinerator: A Techno Thermal Case Study of PLTSa 10 MW Cirebon

Abstract

As Indonesia accelerates its Waste-to-Energy (WtE) program through the Pembangkit Listrik Tenaga Sampah (PLTSa) initiative, independent technical verification of proposed projects is critical to avoid costly design miscalculations. This study presents a techno-thermal simulation and independent verification of a proposed titanium-structured incinerator for the 10 MW, 600 ton/day facility under feasibility study in Cirebon, covering (i) process temperature profiling and dioxin (PCDD/F) formation-risk zoning, (ii) a first-order energy balance from feedstock lower heating value (LHV) to net electrical output, and (iii) post-air-pollution-control (APC) emission compliance. The verification reveals three critical discrepancies. First, the assumed feedstock LHV of 3,363 kcal/kg is 1.5–2.6 times higher than the 1,290–2,270 kcal/kg range typically reported for raw, high-moisture Indonesian municipal solid waste. Second, the combined conversion efficiency of 18% is markedly lower than the 28–35% efficiency reported for modern WtE plants; these two assumptions act in partly offsetting directions, meaning their net effect on the reported 76% capacity mismatch cannot be resolved without plant-specific data. Third, a specific internal inconsistency was identified: the model's net-power formula is not capped at nameplate capacity, producing a physically impossible capacity factor of 135%. Benchmarking against five comparable Indonesian PLTSa projects (Surakarta, Surabaya–Benowo, Semarang, Palembang, and Cirebon itself) shows specific electricity yields of 220–527 kWh per ton of waste, within which the Cirebon plant's planned 10 MW/600 tpd (400 kWh/ton) falls squarely, suggesting the nameplate rating itself is a defensible design choice rather than an undersizing error. Dioxin-risk zoning, using a 400–650 °C de novo formation window, identifies the superheater, economizer, and air-heater zones as high risk; however, the 325 °C APC-inlet zone sits within the 250–350 °C peak de novo window reported in the literature, indicating the model's 400 °C lower bound may understate risk. Emission compliance analysis, cross-checked against the actual Indonesian thermal-waste-treatment standard (Permen LHK No. P.70/2016), shows that the model's sole reported "failure" (particulate matter) does not constitute regulatory non-compliance, as the modeled concentration of 25 mg/Nm³ is well within the national limit of 120 mg/Nm³. Consequently, the reported 76% capacity mismatch, while indicative, is not a validated design flaw. This finding underscores the necessity of grounding screening-level simulations in plant-specific data and verified local regulations to inform sound engineering, policy, and investment decisions in Indonesia's emerging WtE sector.