Generate hydrogen as fuel at natural gas processing plant to reduce carbon dioxide emissions

A method of operating a natural gas (NG) processing plant, comprising:

• receiving feed natural gas from a wellhead;
• removing impurities comprising acid gas, water, and hydrocarbons from the feed natural gas to give product natural gas;
• providing fuel to a burner;
• combusting the fuel via the burner to provide heat for a boiler or a heat recovery steam generator (HRSG), or both, to generate high pressure (HP) steam comprising a pressure in a range of 600 pounds per square inch gauge (psig) to 1500 psig;
• flowing the HP steam across a first turbine to drive the first turbine to generate electricity, wherein flowing the HP steam across the first turbine converts the HP steam to low pressure (LP) steam comprising a pressure less than 150 psig;
• providing the LP steam to users in the NG processing plant, wherein a portion of the LP steam not utilized by the users is excess LP steam in the NG processing plant that exceeds demand of LP steam by the users;
• flowing the excess LP steam across a second turbine to generate electricity;
• electrolyzing steam condensate from the excess LP steam via a water electrolysis unit, thereby generating hydrogen gas, wherein the water electrolysis unit comprises an electrochemical cell comprising a cathode, an anode, and an electrolyte;
• and
• combining a first portion of the hydrogen gas with the fuel provided to the burner.

A method of operating a natural gas (NG) processing plant, comprising:

• receiving feed natural gas from a wellhead system comprising a wellhead;
• processing the feed natural gas for provision of natural gas as product, wherein the processing comprises removing acid gas, water, and hydrocarbons having a greater molecular mass than methane from the feed natural gas;
• discharging steam from a boiler and a heat recovery steam generator (HRSG) to a steam header conduit;
• driving a first turbine with the steam from the steam header conduit to generate electricity, wherein driving the first turbine with the steam lowers pressure of the steam to give low pressure (LP) steam comprising a pressure less than 150 psig;
• providing the LP steam to users in the NG processing plant, wherein a portion of the LP steam provided exceeds demand of LP steam by the users giving the portion as excess LP steam in the NG processing plant;
• driving a second turbine with the excess LP steam to generate electricity, wherein the excess LP steam is condensed into steam condensate by the second turbine or by a condenser heat exchanger downstream of the second turbine, or a combination thereof;
• subjecting the steam condensate to electrolysis, thereby generating hydrogen gas;
• and
• combusting fuel and a first portion of the hydrogen gas in a furnace associated with the boiler or the HRSG, or both, to generate the steam.