Dear Whereisjackbenny,
Thanks for your clarifying the intention of your original post, and well done on reaching the age of 58.
Note that this is not "Hilbert".
Please refer to page 33 of the 3-year old source you are citing. This is the page where the thermal efficiency parameter is cited. Just an assumption, but I suspect the 2021 Pyrogenesis model may have improved upon that thermal efficency.
"To calculate the flow rate and composition of the process gas in the firing zones, certain parameters for the plasma torches had to be specified. These include torch power, thermal efficiency and working gas flow rate. The parameters used for the plasma case study are based on a 2 MW industrial plasma torch from Westinghouse [32], presented in Table 3.3."