Chengrui Qu

Effect of CaO additive on formation of PM 2.5 under O 2 /CO 2 atmosphere during coal combustion

The influence of CaO additive on the emission characteristics of PM<inf>2.5</inf> (particulates with aerodynamic diameter less than 2.5µm) was studied with a tube furnace. The combustion tests were carried out at 1123K under O<inf>2</inf>/CO<inf>2</inf> atmosphere. The PM<inf>2.5</inf> generated from coal combustion was collected and analyzed with an Electrical Low Pressure Impactor (ELPI). The results indicate that CaO is an important factor for the formation of PM<inf>2.5</inf> during coal combustion under O<inf>2</inf>/CO<inf>2</inf> atmosphere. The number and mass concentrations of PM1 diminish, but the number and mass concentrations of PM<inf>1–2.5</inf> enhance slightly after CaO is added. The size distributions of PM<inf>2.5</inf> are similar, which display two peaks around 0.2µm and 2.0µm, respectively. With increasing the additive weight ratio of CaO, the concentrations of S, Pb, Cu, Na and K decrease. The submicron-size ash particles smaller than 0.317µm are formed via nucleation of vaporized ash components, and the supermicron-size ash particles are formed by coagulation and coalescence of the submicron-size ash, and fragmentation and coalescence of mineral matter.

Characteristics of Pd-Rh/CeO 2 /Al 2 O 3 TWC for NO x and PAHs removal in flue gas of MSWI

Pd-Rh/CeO<inf>2</inf>/Al<inf>2</inf>O<inf>3</inf> three-way catalysts by sol-gel method were investigated by catalytic performance test for simultaneous removals NO<inf>x</inf> and PAHs. The experiments were carried out in a laboratory scale incineration system equipped with a catalyst reactor. The catalysts were characterized with BET, SEM, and XRD. The sol-gel way prepared carrier CeO<inf>2</inf>/Al<inf>2</inf>O<inf>3</inf>, characterization results showed that, CeO<inf>2</inf>/Al<inf>2</inf>O<inf>3</inf> the specific surface area is 207m²/g, average pore size is 88.76 Å, pores volume is 0.67 cm³/g. In addition to surface roughness, the surface also appeared in many small crystal particles, suggesting that these small crystals may be Pd crystals. Experimental results showed that the removal efficiency of NO<inf>x</inf>, and PAHs in Pd-Rh/CeO<inf>2</inf>/Al<inf>2</inf>O<inf>3</inf> TWC was generally greater than 80%. The bimetallic catalyst with a Pd/Rh ratio of 1/0.10 was found to have a best activity for highest removal efficiency.

Effect of Al 2 O 3 additive on formation of PM 2.5 in O 2 /CO 2 atmosphere during coal combustion

The influence of Al<inf>2</inf>O<inf>3</inf> additive on the emission characteristics of inhalable particles has been studied with a tube furnace. The combustion tests were carried out at 1123K under O<inf>2</inf>/CO<inf>2</inf> conditions. The inhalable particulates after combustion were collected into an Electrical Low Pressure-Impactor (ELPI). Results indicate that Al<inf>2</inf>O<inf>3</inf> additive is an important factor for the formation of PM<inf>2.5</inf> (particulates with diameters less than 2.5µm) during coal combustion under O<inf>2</inf>/CO<inf>2</inf> atmosphere. The number and mass concentrations of PM<inf>1</inf> diminish, but the number and mass concentrations of PM<inf>1–2.5</inf> enhance slightly after Al<inf>2</inf>O<inf>3</inf> is added. The size distributions of PM<inf>2.5</inf> are similar, displaying two peaks around 0.2µm and 2.0µm, respectively. With increasing the additive weight ratio of Al<inf>2</inf>O<inf>3</inf>, the concentrations of Na, K, Cu and Pb decrease.

Modeling of heavy metals behavior based on fly ash from MSWI in a swirling furnace

Based on the experimental results and existent states of heavy metals in fly ashes and slag, the gas-solid reaction theory during the melting process, heat and mass transfer of particles in fly ashes, chemical dynamics theory such as volatile heavy metals diffuseness, the plentiful experimental datum were analyzed. Theoretical simulated results from the predicted model are basically consistent with experimental data concerning Co, Cu, Ni, Cr, and Mn fixed rates from in swirling furnace. Results indicate that this approach permits to predict the extent of heavy metals vaporization from a glassy matrix, such as As, Cd, Pb, Zn, and Hg, when heavy metals in swirling melting. The model of heavy metals melting reaction and the volatility in particles during fly ashes melting process has been constructed.