Integrated refinery processes and systems for generating hydrogen by direct decomposition of hydrocarbons. The integrated processes and systems can be used to capture carbon and sulfur in solid form, reducing carbon dioxide and sulfur oxide emissions. The processes include reacting sour gas with a metal-based sorbent in a reactor to produce sulfur-bearing solids and water, and to partially reform hydrocarbons in the sour gas to produce hydrogen-rich syngas; and cracking remaining hydrocarbons thermally with or without the presence of a catalyst to produce hydrogen and solid carbon.