Chemical looping conversion characteristics and kinetic behavior of main components in microalgae biomass:Glycine and starch

Biomass chemical looping process (BCLP) could realize the in-situ separation of carbon dioxide with nearly zero energy consumption, making the entire conversion process carbon negative. In this paper, thermal behavior from BCLP of the main components of microalgae was investigated. Glycine (GE) and starch (ST) were selected as the main compounds of protein and carbohydrate of the main organic components of microalga. Using Fe2O3 as the oxygen carrier, thermal behavior and kinetic characteristics of main compounds under different oxygen carrier ratios and different heating rates were studied. The results showed that the chemical looping conversion behavior of GE and ST changed with the change of oxygen carrier ratio and heating rate. By studying the distribution of the main gaseous products and the low calorific value of the sample, it was found that when the mass fraction of Fe2O3 in GE reached 30 %, the low calorific value of the main gaseous products reached the maximum. Under the three heating rates of 10, 20, and 40./min, the maximum low calorific value was 8.98, 9.36 and 10.08 MJ m 3, respectively. When the mass fraction of Fe2O3 in ST reached 30 %, the low heating value of the main gaseous products at the three heating rates reached the minimum, and when Fe2O3 increased to 50 %, the low heating value suddenly rose to the maximum. The kinetic parameters of the main gaseous products showed that the activation energy required for the three gaseous products of CO, CO2 and H-2 released by GE thermal interpretation were all the smallest, which were 6.227 kJ mol(-1).2.645 kJ mol(-1).19.447 kJ mol(-1), respectively. The activation energy required for ST thermal release of CO was the smallest. Besides, ST-Fe-50 needed the least activation energy to release CH4, CO2 and H-2 through chemical looping conversion, which were 13.704 kJ mol(-1).1.824 kJ mol(-1).33.191 kJ mol-1, respectively. The research results in this paper provide references for guiding the selection of microalgae raw materials and the development of chemical looping conversion equipment.

Automated summary

The study investigated the thermal behavior and kinetic characteristics of the main components of microalgae in the biomass chemical looping process. It was found that the chemical looping conversion behavior of the main compounds changed with different oxygen carrier ratios and heating rates. The research results provide references for guiding the selection of microalgae raw materials and the development of chemical looping conversion equipment.