Chi Yong

Simulation study on reconstruction model of three-dimensional temperature distribution within visible range in furnace

This paper presents a reconstruction model of three-dimensional temperature distribution in furnace based on radiative energy images captured by charge-coupled device (CCD) cameras within the visible wavelength range. Numerical simulation case was used in this study and a zigzag eccentric temperature distribution was assumed to verify the model. Least square QR-factorization (LSQR) method was introduced to deal with reconstruction equation. It is found that the reconstructed temperature distributions in low-temperature areas had some fluctuations and high-temperature areas were reconstructed well. The whole reconstruction relative error was mainly due to errors in low-temperature areas and the relative error for highest-temperature reconstruction was quite small.

PCDD/FS emission in a 150T/D MSW and coal co-firing fluidized bed incinerator

Incineration as a method of reducing Municipal Solid Waste (MSW) volume and recovery of energy has been developed gradually in China. More attention is paid on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, (PCDD/Fs) formed in MSW incineration process. This paper presents results of the analysis of PCDD/Fs in the residues of a fluidized bed incinerator co-firing MSW and coal in the Yuhang Thermal Power Plant. The effects of operation conditions and the wet scrubber system on PCDD/Fs formation were also analyzed. PCDD/Fs emitting from the smoke stack was 0.92 I-TEQ ng/Nm3. After the wet scrubber emission of dioxins increased and the shifting of homologue profiles in flue gas was also observed, PCDFs were not detected in the incinerator residues. From this, we can see that in the MSW incineration process, the formation mechanism of PCDFs was different from that of PCDDs. The results will benefit further research on the optimal operation of incinerator and control of PCDD/Fs emission from the MSW incinerator.

Combustion of electronic wastes using a drop tube furnace

High temperature combustion is a key during the pyrometallurgical recycling for electronic wastes. Former researches relating to thermal treatment concentrated on thermal decomposition during electronic wastes pyrolysis and oxidation, using e.g. thermogravimetric analysis (TGA) or lab-scale batch-feeding furnace. In the present research, a bench-scale incineration system was developed to study the combustion of electronic wastes and the emission characteristics. The system features a continuously-fed drop tube furnace. By using it, the combustion proceeds under comparable conditions and the emitted flue gas is steady & uniform, the thermodynamic equilibrium approach for conversions of inorganic halogen could be investigated. It also equips with a cooling & sampling unit for investigating the emission of post-combustion area. The effects of operating conditions on the completeness of combustion and the emission of inorganic Br for waste printed circuit boards were investigated systematically by using this furnace. Under the proposed conditions, the combustion is quiet complete and more than 99.89% organobrominated compounds contained in raw materials are destroyed and convert to HBr & Br2 in flue gas. The two forms of inorganic bromine seem reach thermodynamic equilibrium within 0.25 s. Further experiments could provide the datum for analyzing the combustion performance, the emission characteristics of organic pollutants and the mechanism of chlorinated dioxins (PCDD/Fs) & brominated dioxins (PBDD/Fs) formation by fly ash catalyzed de novo synthesis.

Partitioning of heavy metals during municipal solid waste incineration on a laboratory fluid bed furnace

The content of heavy metals in the main physical compositions of municipal solid waste (MSW) is analyzed. The effects of temperature, chlorine and water on the partitioning of heavy metals are studied using a laboratory fluidized-bed (FB) furnace with simulated MSW composition. The experimental results show that temperature and chloride content in the feed have significant influence on the volatility of heavy metals, especially those of lower boiling point such as Hg, Cd and Zn. The influence of water is slight.