| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程所 === 94 === Abstract
Hydrogen fuel is a very clean alternative fuel which can be used to replace
fossil fuel and reduce the air emission when being used in the industrial boilers
and gas turbines. In this study, the hydrogen-rich processed flare gas originally
planned to be delivered to the flares was recycled into the boiler fuel gas
system for reuse. By doing that, the hydrogen-rich fuel became a viable
alternative fuel and could partially reduce the consumption of natural gas.
The study carried out an on-site test with cogeneration high-pressure steam
boilers in function in refineries. The chosen hydrogen-rich residual-gas
contained 50mole%-80mole% hydrogen in average. The increased amount of
hydrogen decreased C/H proportion of the fuel as well as the generation of
CH，consequently lessened the formation of Prompt NOx、N2O。Increasing
hydrogen considerably reduce the amount of gas after burning, and slowed
down the gas flowing speed in the flares, so that the gas stayed in flares longer,
which was favorable to reduce the amount of Prompt NOx.
The results indicated that in addition to improving the efficiency of
high-pressure steam and electricity-cogenerating boilers and outstanding
material benefits for environment improvement, as to the economic benefit, it
can create a nature gas saving of 7,700,000 m3 per year. As to the
environmental benefit, it can reduce the nitrogen oxides emission by 4.3%, and
carbon dioxide by 20,200 tones annually.
The composition of hydrogen-rich gas was complicated. In view of factors of
safety, stabilization of pressure and so on, the optimized operation mode was
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NG/RG (NG: nature gas; RG: hydrogen-rich refinery gas) with volume flow rate
of 1.8. Under this condition of optimized operation mode, effectiveness of
high-pressure boilers and the effectiveness in reducing the discharged greenhouse
gas were both significantly improved.
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