No abstract

Pyrolysis of wet sewage sludge with a moisture of 86.47 wt % was conducted using electric heating (conventional pyrolysis, CP) and microwave heating (microwave pyrolysis, MWP) separately on two sets of batch reactors. Sixteen polycyclic aromatic hydrocarbons (PAHs) characterized by United States Environmental Protection Agency (U. S. EPA) as priority pollutants were determined by gas chromatography/mass spectroscopy (GC/MS) in gas, liquid, and solid phases of pyrolysis products to get detailed transmission characteristics of PAHs in sewage sludge pyrolysis. Temperatures of 400−900 °C and microwave power of 400−900 W were investigated. Production yields in MWP and CP behaved similarly for different power in MWP and for different temperatures in CP, whereas liquid yielded more than 75% of the total weight for the high content of water in wet sewage sludge. Liquid yield went through a high peak at 500 W for MWP and 700 °C for CP. Total yield of PAHs had trend of increase in MWP, whereas it peaked at 700 °C in CP. Naphthalene, fluorene, phenanthrene, and anthracene contributed most of the yield change, which can be explained by integration of the secondary pyrolysis of solid, decomposition of PAHs and synthesis of gas in different temperature. CP yielded more PAHs than MWP, which is more obvious in gas fraction than oil fraction. Distillation effect had great influence on PAHs distribution between gas and oil fraction. PAHs yield in solid for MWP decreased with increase of power, which might be attributed to the special effect of microwave on the microscope characteristic of solid, whereas PAHs in solid for CP were even lower and would cause fewer environmental problems. The results also indicated "nonthermal" impacts of microwave on the process.

Phonon depletion in the indirect recombination process of bilayer WS2 has been proposed to unveil exceptionally robust valley polarization.

No abstract

No abstract

Activated carbon injection is widely used to control dioxins and mercury emissions. Surprisingly little attention has been paid to its modelling. This paper proposes an expansion of the classical Everaerts-Baeyens model, introducing the expression of fraction of free adsorption sites, f (s), and asserting the significant contribution of fly ash to dioxins removal. Moreover, the model monitors dioxins partitioning between vapour and particulate phase, as well as removal efficiency for each congener separately. The effects of the principal parameters affecting adsorption are analysed according to a semi-analytical, semi-empirical model. These parameters include temperature, contact time during entrained-flow, characteristics (grain-size, pore structure, specific surface area) and dosage of activated carbon, lignite cokes or mineral adsorbent, fly ash characteristics and concentration, and type of incinerator plant.

No abstract

No abstract