Industrial Application of a Deep Purification Technology for Flue Gas Involving Phase-Transition Agglomeration and Dehumidification

A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambient air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide (SO3), water with dissolved salts, and particles in the wet flue gas form secondary pollution in the surrounding atmosphere. In this study, a deep purification technology for flue gas involving phase-transition agglomeration and dehumidification (PAD) is proposed. This deep purification technology includes two technical routes: the integrated technology of phase-transition agglomeration and a wet electrostatic precipitator (PAW); and the integrated technology of phase-transition agglomeration and a mist eliminator (PAM). Industrial applications of PAW and PAM were carried out on 630 and 1000 MW coal-fired units, respectively. The results show that the average amount of recycled water obtained from wet flue gas by means of PAD is more than 4 g·(kg·°C)−1. Decreasing the wet flue gas temperature by 1.5–5.3 °C allows 5%–20% of the moisture in the flue gas to be recycled; therefore, this process could effectively save water resources and significantly reduce water vapor emissions. In addition, the moist plume is effectively eliminated. With the use of this process, the ion concentration in droplets of flue gas is decreased by more than 65%, the SO3 removal efficiency from flue gas is greater than 75%, and the removal efficiency of particulate matter is 92.53%. Keywords: Moist plume, Phase-transition agglomeration, Dehumidification, Dissolved salts, SO3, Particulate matte

An innovative alcohol-solution combustion-calcination process for the fabrication of NiFe2O4 nanorods and their adsorption characteristics of methyl blue in aqueous solution

Magnetic nickel ferrite (NiFe _2 O _4 ) nanorods were prepared via an innovative alcohol-solution combustion-calcination technique and evaluated for removing methyl blue (MB), which may greatly benefit for dye-polluted water treatment. The magnetic nanorods were characterized by TEM, EDS, XRD, VSM, SAED, FTIR, XPS and BET, the results showed that the NiFe _2 O _4 sample has high magnetic saturation (Ms) and soft superparamagnetic behavior, and these properties accounted for their facile separation from the aqueous solution when an external magnetic field was applied. To understand the adsorption mechanism, adsorption experiments were performed using adsorption kinetics and adsorption isotherms. The Temkin model and the pseudo-second-order kinetic model best described the adsorption characteristics of MB onto NiFe _2 O _4 nanorods. The effect of pH on the adsorption process was investigated, when pH was 3–7, the maximum adsorption capacity was reached, which was about 62 mg·g ^−1 . The recycling efficiency was also estimated, after 10 runs of regeneration, it remained 70.1% initial adsorption capacity, indicating the adsorbent could be efficiently reused for the adsorption of MB

Preparation and characterization of magnetic α-Fe2O3/Fe3O4 heteroplasmon nanorods via the ethanol solution combustion process of ferric nitrate

An ethanol solution combustion process of ferric nitrate for preparing magnetic α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods was introduced. The influencing factors, including the solvent type and the calcination conditions, were discussed. Anhydrous ethanol was considered to be the most suitable solvent for the preparation of α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods, and the optimal calcination time was determined to be 2 h. By changing the calcination temperature, α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods with different phase compositions could be obtained, and the mechanism was explained in detail. The results indicated that the rapid combustion method could achieve the controlled preparation of α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods, which provided a general preparation approach for α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanomaterials