| In order to achieve hydrogen(H2)and energy storage with ammonia(NH3)and reduce carbon emissions,this paper focuses on the difference of operating conditions,energy efficiency and emissions with ammonia application to fossil fuel based boilers.Ammonia is used as the substitute of fossil fuels such as C3H8 and CH4.Combustion schemes include fossil fuel-NH3/H2 carbon-reduced combustion,and NH3-H2 zero-carbon combustion.The differences in feedstock,flue gas characteristics and environmental benefits of C3H8/CH4-NH3 fuel,C3H8/CH4-H2(from NH3)fuel at various fuel ratios were studied to support equipment transformation.The results show that the combustion of C3H8/CH4 mixed with NH3/H2 needs bigger fuel intake channel;the adaptability of ammonia fuel to the exhaust pipe of the existing methane boiler is higher than that of the propane boiler;the air supply capacity of the existing equipment is sufficient to ensure the mixing of C3H8/CH4-NH3/H2 fuel has a larger adjustment range for excess air.In terms of environmental benefits,C3H8/CH4-NH3 fuel does better in carbon reduction than C3H8/CH4-H2.Experimental research on C3H8-NH3 combustion was also conducted,with achieved stable combustion in a gas boiler.Results show that using ammonia fuel as a supplement to propane can reduce carbon emissions of the boiler system,but it is difficult to meet the energy utilization efficiency and NO standards at the same time.Thus,the existing equipment needs to be modified.In addition,a carbon-free combustion scheme with NH3 is proposed for cold-heat-water supply.The overall energy utilization efficiency of the system is increased by 12.7%and 95%of the water vapor in the flue gas can be recovered.In summary,this study demonstrstes that application of ammonia as a hydrogen carrier to fossil fuel based boilers is technically feasible both through ammonia-fossil fuel carbon-reduced combustion and ammonia-hydrogen carbon-free combustion. |
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