En Yu Wang

Comparison of De-NOX Performance of Mn/AC and Mn/Bio-Char on Low-Temperature SCR

In low-temperature SCR, corn straws pyrolysis carbon (CS) was prepared as a catalyst support and activated carbon (AC) was a comparison. Manganese (7 wt.%) was loaded respectively on this two supports (Mn/AC and Mn/CS). In 50°C~300°C SCR experiment, the highest NO conversion by using CS is 36.6 Vol.% at 300°C, while AC 37.9 Vol.% at 200°C. After loaded the manganese element, NO conversion increases with the temperature. At 300°C, Mn/AC has the highest NO conversion (81.9 Vol.%), while Mn/AC is 65.3 Vol.%. The sulfur resistance performance test shows that NO conversion decreases with the increasing of SO2 concentration. In the 400ppm SO2 fuel gas at 300°C, using Mn/CS, NO conversion reduces 16.7 Vol.%, however, using Mn/AC, it reduces 22.6 Vol.%. It is promising to apply biomass pyrolysis carbon modified catalyst.

Numerical Simulation on South American Coal Reburning in a Pulverized Coal Combustor

With the increasingly serious impacts of NOx on environment, measures of controlling NOx are extremely necessary. Reburning technology has become a proven and effective method to control the emissions of NOx. In this paper, CFD software has been used to simulate the reburning process of South American coal (SAm) so as to study the effect of the reburning on the combustion in the furnace and NOx reduction. The result shows that, SAm reburning can reduce NOx emissions effectively, and removal rate of NOx reaches 50.63% with respect to the conventional combustion.

Simulation Research about Impacts of Flue Gas on Surrounding Buildings

The revamping project of turning coal-burning boiler into gas-fired boiler for urban heat supply in Tianjin causes high vapor content in flue gas, which has great influences on the day lighting of surrounding buildings. In this paper, CFD software is introduced to simulate the distributions of NOx, SO2 and vapor in space after leaving the chimney and their impacts on surrounding buildings with the effect of the atmosphere. Result shows that flue gas discharged from the chimney with the height of 30 m has significant impacts on the surrounding buildings.

Study on Metal Oxide Catalyst for Selective Catalytic Reduction of NOx at Low Temperature

The method of selective catalytic reduction (SCR) is now one of the mature applications of NOx removal technology, which can meet the practical requirements due to the more stringent laws and regulations on air pollutions. However, the active temperature of traditional SCR catalyst is usually in the temperature range of 300-400°C, which limits the condition of SCR unit. Therefore, low temperature SCR method has caused concern for the scholars in recent years. Catalyst is the key to SCR unit because its performance has a direct influence on the catalytic efficiency. This paper summarizes the research progress of metal oxide catalyst of low temperature SCR. In addition, the future research work is discussed.

Numerical Simulation Research on the Internal Flow of a Heat Exchanger

Spiral tube exchanger is one of the most important heat transfer devices among the electric water boilers. In this paper, CFD software is introduced to simulate the process of the flow of the spiral tube exchanger. Cases with different inlet velocities of the cold water have been conducted and results show that, temperature increment of the cold water reaches 38.87 K, 20.21 K and 12.12 K with the inlet velocity of the cold water set as 0.05 m/s, 0.09 m/s and 0.13 m/s respectively.

Heat Imbalance Analysis of a Hybrid Ground-Source Heat Pump System

Operating data in the last two years of a hybrid ground-source heat pump system (HGSHPS) were analyzed, and were contrasted to TRNSYS simulation results. Heat extraction from the borehole heat exchanger (BHE) of ground-source heat pump system (GSHPS) was too much larger than the heat injection, but heat extraction from the borehole thermal energy storage (BTES) of solar assisted GSHPS (SAGSHPS) was too less than the heat storage, in 2012. Serious problem of heat imbalance of BHE occurred, and the GSHPS almost could not work in the late heating season of 2012. An adjusted operating strategy was utilized in 2013. The ground temperature imbalance for GSHPS and heat excess for SAGSHPS were resolved. It is important to monitor the operation of HGSHPS to resolve the heat imbalance problem.

Effects of Biomass and Crude Oil Co-Combustion on NO and SO2 Emissions

In this paper, a tube electric furnace is used to process the co-combustion of biomass and crude oil in air atmosphere, the influence of the biomass mass fraction and the temperature on NO and SO2 emissions are analysed. Research shows that with the increasing addition ratio of biomass to crude oil, the amount of NO in per unit heat reduces. This tendency is more apparent at high temperatures. Compared with crude oil, the NO emission of 20% biomass mass fraction at 1100°C is reduced by 25.8% while 19.02% at 700°C. SO2 emission in per unit heat decreases with the increasing biomass mass fraction. This tendency is more apparent at low temperatures. Compared with crude oil The generation of SO2 of 20% biomass mass fraction can reduce 91.5% at 700°C while 36.7% at 1100°C.

Numerical Simulation Research on the Heating Process of Air by Waste Heat

Flue gas of boiler is a kind of great potential waste heat resource. Relatively high temperature of exhaust has caused a vast waste of energy and serious environmental thermal pollutions. To make a full and reasonable use of the heat resource, a simplified single-tube heat exchanger is introduced in this paper. Dry air and wet air with different temperatures transfer heat with flue gas in the same model. And the results show that heat near the inner wall exchanges more violently than any other space in the heater. For dry air, the higher temperature of the air enters into the heater, the lower heat transfer effect of the heater. Heat exchange effect of the wet air with 0.03 mole fraction of water is more higher than that of dry air in this model.

Experimental Study on Biomass Char Combustion in O2/CO2 Atmosphere

Experiments of biomass char combustion in 10%O2/90%CO2, 21%O2/79%CO2, 10%O2/90%N2 and 21%O2/79%N2 atmospheres were performed in the fixed-bed reactor system at the temperature of 800°C-1200°C. The results show that at the same temperature, NO emission is higher in O2/N2 atmosphere than that in O2/CO2 atmosphere. The higher the O2 concentration is, the higher the NO yield is. As the temperature rises, the NO yield rises at first and then decreases at the same O2 concentration and atmosphere.

Influence of Jet Angle on Diffusion Flames in Centrifugal Field

Diffusion combustion of propane and air in a rotational combustor was simulated by three-dimensional numerical model based on FLUENT. Influence of centrifugal field on the flame shapes and temperatures were discussed under various jet angles changing in the plane perpendicular to the rotational axis. The flame is compressed when the value of jet angle θ is less 90°, otherwise, the flame is stretched when |θ|>90°. When θ<90°, the deflection of flame becomes larger with an increase of θ. As contrasted to positive θ cases, the zones of high temperature in combustion chamber corresponding to negative are larger, and the maximal flame temperatures are likewise larger. The negative jet angle is useful to flame stability. External fluid is an important factor influence the distribution of temperature in combustion chamber.