What are the main utility systems in a chemical plant?

Main utility systems: Steam - multiple pressure levels (HP, MP, LP), used for heating, driving turbines; sized from steam balance. Cooling water - removes process heat, recirculated with cooling towers; sized for total duty. Instrument air - clean, dry air for pneumatic instruments; typically 6-7 barg. Nitrogen - inert blanketing, purging; from plant or cryogenic supply. Plant air - general service, not instrument quality. Fuel gas - fired heaters, flares. Power - purchased or generated; emergency generation for critical loads. Each utility requires: generation/supply capacity, distribution network, control and monitoring, and consumption tracking. Utility balances ensure adequate supply for all operating cases.