Experimental Study on Ammonia Co-Firing with Coal for Carbon Reduction in the Boiler of a 300-MW Coal-Fired Power Station

To reduce CO_(2) emissions from coal-fired power plants,the development of low-carbon or carbon-free fuel combustion technologies has become urgent.As a new zero-carbon fuel,ammonia(NH_(3))can be used to address the storage and transportation issues of hydrogen energy.Since it is not feasible to completely replace coal with ammonia in the short term,the development of ammonia-coal co-combustion technology at the current stage is a fast and feasible approach to reduce CO_(2) emissions from coal-fired power plants.This study focuses on modifying the boiler and installing two layers of eight pure-ammonia burners in a 300-MW coal-fired power plant to achieve ammonia-coal co-combustion at proportions ranging from 20%to 10%(by heat ratio)at loads of 180-to 300-MW,respectively.The results show that,during ammonia-coal co-combustion in a 300-MW coal-fired power plant,there was a more significant change in NO_(x) emissions at the furnace outlet compared with that under pure-coal combustion as the boiler oxygen levels varied.Moreover,ammonia burners located in the middle part of the main combustion zone exhibited a better high-temperature reduction performance than those located in the upper part of the main combustion zone.Under all ammonia co-combustion conditions,the NH_(3) concentration at the furnace outlet remained below 1 parts per million(ppm).Compared with that under pure-coal conditions,the thermal efficiency of the boiler slightly decreased(by 0.12%-0.38%)under different loads when ammonia co-combustion reached 15 t·h^(-1).Ammonia co-combustion in coal-fired power plants is a potentially feasible technology route for carbon reduction.

Mechanistic study on 4,4'-sulfonylbis removal with CO_(2)/Ar gas-liquid DBD plasma

In this study,a single dielectric barrier discharge(DBD)coaxial reactor was used to degrade 4,4'-sulfonylbis(TBBPS)in water using greenhouse gas(CO_(2))and argon as the carrier gases.The investigation focused on CO_(2)conversion,reactive species formation,gas-liquid mass transfer mechanism,and degradation mechanism of TBBPS during the discharge plasma process.With the decrease of CO_(2)/Ar ratio in the process of plasma discharge,the emission spectrum intensity of Ar,CO_(2)and excited reactive species was enhanced.This increase promoted collision and dissociation of CO_(2),resulting in a series of chemical reactions that improved the production of reactive species such as·OH,^(1)O_(2),H_(2)O_(2)and O_(3).These reactive species initiated a sequence of reactions with TBBPS.Results indicated that at a gas flow rate of 240 mL/min with a CO_(2)/Ar ratio of 1:5,both the highest CO_(2)conversion rate(17.76%)and TBBPS degradation rate(94.24%)were achieved.The degradation mechanism was elucidated by determining types and contents of reactive species present in treatment liquid along with analysis of intermediate products using liquid chromatography-mass spectrometry techniques.This research provides novel insights into carbon dioxide utilization and water pollution control through dielectric barrier discharge plasma technology.