Waste Treatment Costs for Non-Phosgenation Based Polycarbonate Production

Published January 2020

This review provides definition and detailed analysis of waste treatment operations required to meet environmental discharge requirements for Asahi Kasei’s non-phosgenation based polycarbonate (PC) process. The amount and compositions of all waste streams potentially generated by the PC process are considered with sizing and costing of treatment units for liquid, gaseous, and solid waste.

Wastewater treatment (WWT) typically accounts for 60–80% of total waste treatment capital requirements in most petrochemical conversion processes. In the present case, WWT costs amount to 71% of total fixed capital (TFC). While most of the liquid and gaseous waste chemicals are incinerated in this process, we find that the simple incineration system is inexpensive compared to the multi-section process required for WWT.

The waste treatment costs estimated herein are compared with the capital costs estimated for a PC process using Asahi Kasei’s technology at a plant capacity of 260 ktpa. In this explicit analysis, we find that waste treatment accounts for 16% of total TFC for the PC plant. This result is within our less rigorous but traditional estimation guidelines, which have ranged from about 5 to 30% of TFC. But the waste treatment costs estimated in this explicit analysis are much higher than the traditional default estimate, which typically amounts to 5% of BLI and is often taken as the combined costs of liquid, gas, and solid waste treatment facilities for petrochemical plants.