508 / 2018-12-31 22:46:12

Thermodynamic simulation and kinetic analysis on chemical looping with oxygen uncoupling (CLOU) of lignocellulosic biomass main compound: cellulose

Thermodynamic simulation; kinetic analysis; lignocellulosic biomass;chemical looping with oxygen uncoupling (CLOU)

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Chemical looping with oxygen uncoupling (CLOU) can burn biomass in an efficient method with CO2 capture[1]. During the CLOU process, the oxygen carrier transferred molecular oxygen in the fuel reactor and regenerated in the air reactor at high temperature, as shown in equation (1) and (2). Cu-based and Mn-based materials have been selected as oxygen carriers[2-4]. Pinewood chips and other kind of biomass was tested in bubbling fluidized bed via CLOU. The main organic compounds of wood and other lignocellulosic biomass are cellulose, hemicellulose, and lignin. Thus, investigation of the main organic compounds of biomass can provide basic information about the behavior during CLOU process.
4CuO→2Cu2O＋O2(g) ΔH850＝263.2 kJ·mol-1 (1)
2Cu2O＋O2(g)→4CuO ΔH850＝-263.2 kJ·mol-1 (2)
In this research, cellulose was selected one of the typical organic compound and CuO was selected as the oxygen carrier. Products distribution under different reaction temperature (from 700 oC to 850 oC) and mixing ratio of CuO (10 wt.%, 30 wt.%, 50 wt.%)) were explored in a fixed-bed reactor combined with an on-line mass spectrometer. Isothermal conversion method was used to calculate the kinetic parameters. The results indicated that main gaseous products from CLOU of cellulose was CO2 and CO. As can be seen from Figure 1, the highest yield of H2 and CH4 was obtained at 10 wt.% of CuO under 850 oC, while the highest yield of CO was obtained at 10 wt.% of CuO under 700 oC. Conversion of the CO2 from CLOU of cellulose with 10 wt.% CuO from 700 oC to 850 oC is shown in Figure 2. The releasing characters of the gaseous products were tracked by the on-line mass spectrometer.