Reduction of energy cost and CO₂ emission for the boilers in a full-scale refinery plant by adding waste hydrogen-rich fuel gas

The use of hydrogen-containing fuel in gas turbines and industrial burners can benefit both losses of radiative heat and emission of pollutants. In this study, worthless waste hydrogen-rich fuel gas (RG) was led into a high-pressure boiler or a medium-pressure boiler in the fuel system to partially replace fuel oil (FO) and/or natural gas (NG) in a full-scale petrochettristry plant. Two sets of inlet fuel flow rate ratios were examined to evaluate the reductions of boiler energy consumption and CO₂ emission. The result showed that for the high-pressure boiler at a loading of 75%, the usage of NG can be 13 × 10⁶ m³/y less and the CO'2 emission can be 2.2 × 10⁴ tons/y lower by changing the inlet FO:NG:RG ratio from 1:1:0 to 1:0.65:0.35. Meanwhile, for the medium-pressure boiler at a loading of 70%, the usage of NG can be cut by 8 × 10⁶ m³/y and the CO₂ emission can be 3.0 × 10⁴ tons/y lower by changing the inlet FO:RG ratio from 1:0.2 to 1:0.7. Therefore, the addition of RG has practical benefits on both energy saving and the reduction of greenhouse gas emission.