Huazhong University of Science and Technology — Publications

Ash Formation and Fouling during Combustion of Rice Husk and Its Blends with a High Alkali Xinjiang Coal

Article

Limited data from fluidized bed combustion tests have shown that rice husk, a silicon-rich residual biomass, has the potential to be cofired with coal while not inducing unacceptable ash-related problems. However, there is great concern regarding the behavior of rice husk ash under pulverized fuel combustion conditions, where the temperatures are much higher and expected to facilitate fuel interactions. This work, to the authors' knowledge, is the first to investigate both ash formation and fouling behavior in rice husk firing and its cofiring with coal at a high temperature relevant to pulverized fuel combustion. A Chinese rice husk and a high alkali Xinjiang coal were selected. Combustion tests of individual fuels and their blends (with the share of rice husk being 10% and 20%, respectively) were performed at 1573 K on a laboratory drop tube furnace. Both bulk ash and fouling deposit samples were collected in each test. Techniques including X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), and ash fusion temperature testing were used for sample characterization. The results show that the rice husk ash generated at 1573 K is dominated by amorphous silica with only a trace amount of quartz. Partial melting of ash particles is observed and attributed to enhanced formation of potassium silicates, which were not found in fluidized bed combustion. Nevertheless, such differences do not seem to change the nonfouling nature of rice husk ash. The ash from cofiring rice husk and coal possesses similar crystalline structures to the coal ash, but extensive fuel interactions are observed. The high fouling tendency of the coal ash is greatly reduced by cofiring with rice husk. The effects of rice husk are both physical and chemical in nature. The presence of high-fusion-temperature, nonsticky rice husk ash in the deposits and the capture of fouling-inducing species from coal by rich husk ash are considered to play important roles in reducing ash fouling. The nonlinear dependence of ash fouling tendency on the rice husk ratio, as found in fluidized bed combustion, is also observed. This work suggests that rice husk may also be cofired with coal in pulverized fuel boilers while not causing significant ash-related problems, though further investigations are still necessary.

Jianqun Wu, Dunxi Yu, Xianpeng Zeng et al. 2017

Publications

Laser polishing of additive manufactured tool steel components using pulsed or continuous-wave lasers

PEELING FAILURE OF REINFORCED CONCRETE BEAMS WITH EXTERNALLY BONDED STEEL PLATES

Reactivation of CaO-based sorbents via multi-acidification under N2 or oxy-fuel (with and without SO2) calcination conditions

Application of visbreaking technology in quench system of Daqing ethylene device

Experimental study on T-shaped reinforced concrete beams with locally reduced cross-sections

Novel multi-dimensional evaluation for rural integrated energy systems based on combined weighting method-cloud model

Adjunctive 980-nm Diode Laser Therapy in the Management of Acute Pericoronitis: A Prospective Randomized Controlled Trial

Behavior of FRP spiral-confined concrete under concentric compression

Shear strengthening of RC beams with NSM FRP strips: Concept and behaviour of novel FRP anchors

Compressive behavior and strength model of novel FRP-UHPC strengthened RC columns

Chloride-binding capacity of cement-GGBFS-nanosilica composites under seawater chloride-rich environment

Sustainable eutectic mixture strategy of molten salts for preparing biochar with interconnected pore structure from algal residue and its performance in aqueous supercapacitor

Ash Formation and Fouling during Combustion of Rice Husk and Its Blends with a High Alkali Xinjiang Coal

End cover separation in RC beams strengthened in flexure with bonded FRP reinforcement: simplified finite element approach

Circular hybrid double-skin tubular columns with a stiffener-reinforced steel inner tube and a large-rupture-strain FRP outer tube: Compressive behavior

Study of Station Blackout Caused Severe Accident Process in Daya Bay Nuclear Power Station

Effect of carbon dioxide on the high temperature transformation of siderite under low oxygen conditions

Finite element modelling of RC beams strengthened in flexure with NSM FRP and anchored with FRP U-jackets

Study on simplified calculation method for the vibration characters of frame-shear wall structures

Strength Model for Debonding Failure in RC Beams Flexurally Strengthened with NSM FRP and Anchored with FRP U-Jackets