Completed a 72-hour run on a 1 t/h H2-DRI pilot at 700°C: 94% metallization on 10–12 mm pellets, about 60–65 kg H2/t Fe net make-up, and about 0.5 MWh/t recovered via off-gas heat. Biggest snag remains recycle compression parasitics and occasional sticking unless we hold about 2 vol% H2O in the make-up — has anyone optimized heat integration on the H2 loop (steam ejector vs mechanical compression) to shave kWh/t and keep the footprint under 100 kg CO2/t?
We ran a 1.2 t/h skid around 700°C and the sticking was killing us, . > and occasional sticking unless we hold about 2 vol% H2O in the make-up — has anyone optimized heat integration We tied a steam ejector to the off-gas WHRU using 3–4 bar steam to pull about 15% of the recycle; that cut compressor power about 20% and let us hold about 2% H2O without extra injection. Small caveat: once make-up dipped near 60–65 kg H2/t Fe the ejector lost lift, so a tiny purge plus an intercooler before the blower kept the dew point in check.
We cut recycle parasitics and kept the ejector out of surge by intercooling the loop to about 35°C before the blower, then reheating with off‑gas; sticking also eased because dew point control got tighter — @n_harper22 did you add a small knock-out before the ejector?