Lian Sheng Liu

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.

Experimental Research on Catalysts of V2O5/AC and V2O5/CNTs for Low Temperature SCR Denitrification

Two catalysts (V2O5/AC and V2O5/CNTs) with different loadings, prepared by impregnation method, were used to research the DeNOx activity under N2 and CO2 atmospheres respecitively at the temperature range from 100°C to 300°C using a fixed bed reactor. Effects of temperature, loading and support on the DeNOx activity were studied. The results show that the NO conversion of the both catalysts increases with the reaction temperature. The loading and support have significant effects on the activities. 9%V2O5/AC and 9%V2O5/CNTs yielded 80% and 66.6% NO conversion at 250°C respectively under N2 atmosphere, however, they yielded 78.1% and 75.1% respectively under CO2 atmosphere.

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.

Numerical Study on Supersonic Combustor with an Allotype Cavity

The three-dimensional coupled explicit Reynolds Averaged Navier–Stokes (RANS) equations and the two equation shear-stress transport k-w (SST k-w) model has been employed to numerically simulate the cold flow field in a special-shaped cavity-based supersonic combustor. In a cross-section shaped rectangular, hypersonic inlet with airflow at Mach 2.0 chamber, shock structures and flow characteristics of a herringbone-shaped boss and a herringbone-shaped cavity models were discussed, respectively. The results indicate: Firstly, according to the similarities of bevel-cutting shock characteristics between the boss case and the cavity case, the boss structure can serve as an ideal alternative model for shear-layer. Secondly, the eddies within cavity are composed of herringbone-spanwise vortexes, columnar vortices in the front and main-spanwise vortexes in the rear, featuring tilting, twisting and stretching. Thirdly, the simulated bottom-flow of cavity is in good agreement with experimental result, while the reverse flow-entrainment resulting from herringbone geometry and pressure gradient. However, the herringbone-shaped cavity has a better performance in fuel-mixing.

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.

Experimental Study and Mechanism Analysis of Effervescent Atomization

T he flow and spray characteristic of effervescent atomization nozzle has been studied experimentally and the i nner flow field was analyzed with numerical method. Experiments show that the injection pressure and air/liquid ratio (ALR) are the major factors impacting the atomization stability, and the flow coefficient of the nozzle ranged in 0.1-0.15. The VOF simulation of the inner flow field of the nozzle reveals the general transformation process of the bubble, and the region near the exit orifice plays the dominant role during the atomization proces s where miniature bubbles are generated, expanded in size and accelerated and interacting with the local flow field.

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.

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.