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Attrition Behavior of Oxygen Carrier Particles and Pressure Fluctuations in Chemical Looping Systems

Shah, Vedant Ravindra

Abstract Details

2018, Master of Science, Ohio State University, Chemical Engineering.
Chemical looping process deals with conversion of fossil fuels into desired products by making use of oxygen carrier particles. These particles transfer their oxygen to the fuel in reducer reactor and themselves get reduced. The reduced particles are sent to the combustor reactor where they are re-oxidized using air. Thus, the oxygen carrier particles are subjected to multiple redox cycles. Oxygen carrier particles are subjected to high stress, which originates from harsh operating conditions like elevated temperatures, high pressure and chemical reactions. After multiple cycles, the particles tend to lose their strength and become more susceptible to breaking. This phenomenon is known as attrition. Apart from operating conditions and chemical reactions, process conditions such as presence of cyclones, gas jets in combustor reactor, etc. also contribute to attrition of oxygen carrier particles. This work deals with study of attrition behavior of oxygen carrier particles developed by OSU which presented excellent resistance towards attrition. To characterize the tendency of particle to undergo attrition, jet cup test rig was used to quantify attrition. Jet cup studies were used to compare the attrition behavior of oxygen carrier particles before and after chemical reactions. Various parameters affecting jet cup attrition like jet velocity, particle loading in the jet cup, dimeter of particles were studied. Also, jet cup was used to analyze the attrition behavior of particles that were sampled from different locations along the moving bed reducer reactor. This helped to analyze the strength of particles as they went under different extents of IV reduction in the moving bed reducer reactor. As combustor reactor forms an essential part of chemical looping processes, this work also focused on understanding the effect of various parameters on pressure fluctuations that occurred in the combustor reactor. Effect of different parameters like aspect ratio of fluidized bed, column diameter, gas velocity, etc. on pressure fluctuation amplitude and frequency was studied. This study helped to understand the role of aspect ratios on various regimes of fluidization. Aspect ratio, which is defined as the ratio of height of particle bed at minimum fluidization to column diameter significantly affects the performance of combustor reactor as well as the economics associated with it. Experiments were done to understand pressure fluctuations that are associated with different regimes of fluidization. It was found out that the frequency of fluctuations increased with increase in superficial gas velocity. Also, fluctuation frequency was found to be dependent on aspect ratio of the fluidization column. All these observations were consistent with data reported in literature. Conclusions were drawn based on the findings and mechanistic approach was used to propose suitable reasoning. Future work regarding these experiments would include use of Electrical capacitance volumetric tomography (ECVT) to correlate the pressure fluctuation data with capacitance data to image the fluidized bed.
Liang-Shih Fan (Advisor)
Andre Palmer (Committee Member)
74 p.

Recommended Citations

Citations

  • Shah, V. R. (2018). Attrition Behavior of Oxygen Carrier Particles and Pressure Fluctuations in Chemical Looping Systems [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523455164766952

    APA Style (7th edition)

  • Shah, Vedant. Attrition Behavior of Oxygen Carrier Particles and Pressure Fluctuations in Chemical Looping Systems. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1523455164766952.

    MLA Style (8th edition)

  • Shah, Vedant. "Attrition Behavior of Oxygen Carrier Particles and Pressure Fluctuations in Chemical Looping Systems." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523455164766952

    Chicago Manual of Style (17th edition)