Investigation of the Effects of a Large Percentage of Dried Sludge on the Operation of a Coal-Fired Boiler

A 600 MW coal-fired boiler with a four-corner tangential combustion mode is considered here to study the combustion features and pollutant emissions at different loads for large-percentages of blending dried sludges.The influence of the over-fired air(OFA)coefficient is examined and the impact of the blending ratio on the boiler operation is explored.The results show that for low blending ratios,a slight increase in the blending ratio can improve the combustion of bituminite,whereas a further increase leads to the deterioration of the combustion of blended fuels and thus reduces the boiler efficiency.Enhancing the supporting capability of the secondary air effectively reduces the slagging degree in the bottom ash hopper and improves the burnout rate of coals.For a large-percentage blending case at full load,it is found that the OFA coefficient must be reduced appropriately,otherwise,a secondary high-temperature combustion zone can be generated in the vicinity of the furnace arches,causing high temperature slagging and superheater tube bursting.Considering the influences of combustion and pollutant emissions,the recommended OFA coefficient is 0.2.Blending dried sludge under low loads increases the flue gas temperature at the furnace exit.While reducing the flue gas temperature in the main combustion region,which is beneficial to the safe operation of the denitrification system.Increasing the blending ratio and reducing load lead to an increase in NOx concentration at the furnace exit Sludges with low nitrogen content are suggested for the practical operation of boilers.

Highly emissive coordination polymer derived from tetraphenylethylene-tetrazole chromophore:Synthesis,characterization and piezochromic luminescent behavior

Solid-state materials that exhibit pressure stimulus-response characteristics in a manner of emission signal,known as piezochromic luminescence(PCL),demonstrate great potential in photoelectric devices.The weakened luminescence and insignificant color change in the aggregation state,however,hampers their practical applications.Herein,a highly emissive coordination polymer,[Zn2(H4TTPE)(H2O)4]·H2O(CUST-805),is successfully constructed by employing an AIE-active chromophore as the building block.The structural characterization and photophysical properties are systematically studied.Owing to intrinsic twisted conformation and AIE feature of tetraphenylethylene-tetrazole ligand,CUST-805 achieves the visible and reversible PCL from blue to green switched by different external stimuli.The transformation between crystalline and amorphous states is proved to be the origin of present PCL behavior.Moreover,on basis of electron and energy transfer quenching mechanism,the highly selective and sensitive sensor based on CUST-805 is realized,showing the low detection limit of 0.29 ppm towards 2,4,6-trinitrophenol.

Rational design of AIE-active biodegradable polycarbonates for high-performance WLED and selective detection of nitroaromatic explosives

Luminescent polymers have garnered considerable research attention for their excellent properties and wide range of applications in multi-responsive materials,bioimaging,and photoelectric devices.Thereout,various modulations of polymer structure are often the main approach to obtaining materials with different luminescent colors and functions.However,polymers with biodegradability,tunable color,and efficient emission simultaneously remain a challenge.Herein,we report a feasible strategy to achieve degradable and highly emissive polymers by exquisite combination and interplay of aggregation-induced emission(AIE)unit and environmental-friendly epoxide/CO_(2)copolymerization.A series of polycarbonates P-TEP_(x)CN_(y)(x=0,1,2,4,30,120;y=0,1)were prepared,with emission color changed from blue to yellow by controlling the proportion of two designed AIE-active monomers.Among them,Using P-TCN as emitting layer,high performance white light-emitting diode(WLED)device with an external quantum efficiency(EQE)of 26.09%and CIE coordinates of(0.32,0.32)was achieved.In addition,the designed polymers can be used as selective sensors for nitroaromatic compounds in their nanoaggregate states.