Effect of operating parameters on the performance of thermally regenerative ammonia-based battery for low-temperature waste heat recovery

This study investigated the important factors that affect the operating parameters of thermally regenerative ammoniabased batteries(TRABs),including the metal electrode type,membrane type,electrode surface area,electrode distance,electrolyte concentration,and ammonia concentration.The experimental results showed that the maximum power density of TRABs with a Cu electrode was 40.0 W·m^(2),which was considerably higher than that with Ni(0.34 W·m^(2))and Co(0.14 W·m^(2))electrodes.TRABs with an anion exchange membrane had a 28.6%higher maximum power density than those with a cation exchange membrane.An increased electrode surface resulted in an increased maximum power but a decreased maximum power density.Within a certain range,TRAB performance was enhanced with decreased electrode distance and increased electrolyte concentration.An increased ammonia concentration resulted in enhanced ammonia transfer and improved the TRAB performance.

Investigation on condensable particulate matter emission characteristics in wet ammonia-based desulfurization system

Particulate matter emissions from ammonia-based wet flue gas desulfurization(AmmoniaWFGD)systems are composed of a filterable particulate matter and a condensable particulate matter(CPM)portion.However,the CPM part has been ignored for a long time,which results in an underestim ation of the aerosol problems caused by Ammonia-WFGD systems.In our research,the characteristics of the CPM that emits from an Ammonia-WFGD system are investigated experimentally for the first time,with the US Environmental Protection Agency Method 202 employed as the primary measurement.The influences of some essential desulfurizing parameters are evaluated based on the experimental data.The results show that CPM contributes about 68.8%to the total particulate matter emission.CPM consists mainly of ammonium sulfates/sulfites,with the organic part accounting for less than 4%.CPM is mostly in the submicron fraction,about 71.1%of which originates from the NH3-H2O-SO2 reactions.The appropriate adjustments for the parameters of the flue gas and the desulfurizing solution can inhibit CPM formation to different extents.This indicates that the parameter optimizations are promising in solving CPM emission problems in Ammonia-WFGD systems,in which the pH adjustment alone can abate CPM emission by around 49%.The opposite variations of the parameters need attention because they can cause tremendous CPM emission increase.

Performance of a thermally regenerative ammonia-based battery using gradient-porous copper foam electrodes

Gradient-porous copper foam electrodes were applied to alleviate the adverse effects of the uneven current distribution of electrodes along the electrolyte flow direction in thermally regenerative ammonia-based batteries(TRABs).The results indicated that gradient-porous copper foam with a decreasing pore size(TRAB-LMS)provided the most uniform current distribution and generated the highest power density(15.5 W/m^(2)),total charge(1800 C)and energy density(1224 W h/m^(3)).With the increase in flow rate,the power density of the TRAB-LMS increased considerably within a certain range and then decreased slightly,with the optimal flowrate at 15 mL/min.Under the optimal flow rate,the performance of TRAB-LMS increased when the ammonia concentration rose from 0.5 to 2 M(1 M=1 mol L^(-1));however,it decreased slightly when the ammonia concentration further increased to 3 M.The slight decrease in the cathode potential suggested that the flow and ammonia concentration beyond the optional values facilitated not only the transfer of ammonia into the porous anode,but also the crossover of ammonia from the anode to the cathode.