How do you manage hydrogen balance in a refinery?

Hydrogen balance matches supply with demand. Supply sources: catalytic reformer (main source, ~60%), steam methane reforming (SMR) units, electrolysis (emerging). Demand: hydrotreaters (largest consumer), hydrocracker, other hydroprocessing. Balance management: reformer severity affects hydrogen yield, import hydrogen from merchant suppliers if deficit, export excess (rare). Quality considerations: reformer hydrogen contains light hydrocarbons, requires purification (PSA) for sensitive consumers like hydrocracker. Network optimization: cascade hydrogen from high-purity to lower-purity users, recover hydrogen from purge streams, compress and recycle where economic. Increasing clean fuel requirements have raised hydrogen demand significantly. Many refineries now hydrogen-limited, requiring SMR or imports.