Research on prediction model of formation temperature of ammonium bisulfate in air preheater of coal-fired power plant

Ammonium bisulfate(ABS)is a viscous compound produced by the escape NH_(3) in the NO reduction process and SO_(3) in the flue gas at a certain temperature,which can cause the ash corrosion of the air preheater in coal-fired power plants.Therefore,it is essential to study the formation temperature of ABS to prevent the deposition of ABS in air preheaters.In this paper,the SO_(3) reaction kinetic model is used to analyze the SO_(3) generation process from coal combustion to the selective catalytic reduction(SCR)exit stage,and the kinetic model of NO reduction is used to analyze the NH_(3) escape process.A prediction model for calculating the ABS formation temperature based on the S content in coal and NO reduction parameters of the SCR is proposed,solving the difficulty of measuring SO_(3) concentration and NH_(3) concentration in the previous calculation equation of ABS formation temperature.And the reliability of the model is verified by the actual data of the power plant.Then the influence of S content in coal,NH_(3)/NO_(x) molar ratio,different NO_(x) concentrations at SCR inlet,and NO removal efficiency on the formation temperature of ABS are analyzed.

Electronically Controlling the System of Preheating Intake Air by Flame for Diesel Engine Cold-Start

In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self ignite at the end of compression process at different temperatures of coolant and intake air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro controller unit (MCS 8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.

Experimental investigation and optimization of the gasification parameters of macadamia nutshells in a batch-fed bubbling fluidized bed gasifier with air preheating

Gasification of biomass waste has a significant potential to reduce environmental impact and promote sustainability by producing syngas,which is considered as renewable energy.This work investigated the gasification of macadamia nutshells in air-preheated,batch-fed fluidized bed gasifier.The study conducted a parametric analysis to assess the effect of equivalence ratio(ER)and air temperature on the gasifier temperature profile and its performance based on gas composition,higher heating value(HHV),and gas yield.The research was conducted within the range of 0.15-0.35 for the ER and 25-825℃ for the air temperature.Multi-objective numerical optimization was conducted using response surface methodology(RSM).From the parametric study,a distinct temperature profile was observed along the gasifier height,with the peak temperature near the top of the fluidized bed section and the lowest temperature at the top of the gasifier.Air preheating mostly favored gasification temperature at the lower part of the gasifier and showed rare significance at the top.No improvement in gasifier performance was observed beyond an air temperature of 620℃,which was identified as the ideal air-preheating temperature.Analysis of variance(ANOVA)revealed that the ER was the most influential parameter in the production of combustible gasses,syngas HHV and gas yield.Air preheating did not have a significant effect on methane production and gas yield.The most optimal values for ER and air temperature were obtained as 0.195℃ and 620℃,respectively,producing optimal values of 9.54,14.65%,2.03,4.02 MJ⋅Nm^(-3),and 1.82 Nm^(3)⋅kg^(-1) for hydrogen,carbon monoxide,methane,HHV,and gas yield,respectively.

Lowering the cost of large-scale energy storage:High temperature adiabatic compressed air energy storage

Compressed air energy storage is an energy storage technology with strong potential to play a significant role in balancing energy on transmission networks,owing to its use of mature technologies and low cost per unit of storage capacity.Adiabatic compressed air energy storage(A-CAES)systems typically compress air from ambient temperature in the charge phase and expand the air back to ambient temperature in the discharge phase.This papers explores the use of an innovative operating scheme for an A-CAES system aimed at lowering the total cost of the system for a given exergy storage capacity.The configuration proposed considers preheating of the air before compression which increases the fraction of the total exergy that is stored in the fom of high-grade heat in comparison to existing designs in which the main exergy storage medium is the compressed air itself.Storing a high fraction of the total exergy as heat allows reducing the capacity of costly pressure stores in the system and replacing it with cheaper thermal energy stores.Additionally,a configuration that integrates a system based on the aforementioned concept with solar thermal power or low-medium grade waste heat is introduced and thoroughly discussed.

Dome Combustion Hot Blast Stove for Huge Blast Furnace

In Shougang Jingtang 5 500m 3 huge blast furnace ( BF ) design , dome combustion hot blast stove ( DCHBS ) technology is developed.DCHBS process is optimized and integrated , and reasonable hot blast stove ( HBS ) technical parameters are determined.Mathematic model is established and adopted by computational fluid dynamics ( CFD ) .The transmission theory is studied for hot blast stove combustion and gas flow , and distribution results of HBS velocity field , CO density field and temperature field are achieved.Physical test model and hot trail unit are established , and the numeral calculation result is verified through test and investigation.3-D simulation design is adopted.HBS process flow and process layout are optimized and designed.Combustion air two-stage high temperature preheating technology is designed and developed.Two sets of small size DCHBSs are adopted to preheat the combustion air to 520-600℃.With the precondition of BF gas combustion , the hot blast stove dome temperature can exceed 1 420 ℃. According to DCHBS technical features , reasonable refractory structure is designed.Effective technical measures are adopted to prevent hot blast stove shell intercrystalline stress corrosion.Hot blast stove hot pipe and lining system are optimized and designed.After blowing in , the blast temperature keeps increasing , and the monthly average blast temperature reaches 1 300℃ when burning single BF gas.