• Energy Research

Chemical looping steam reforming (CL-SMR) thermodynamic analysis and process simulation using Fe2MnO4 as an oxygen carrier.

This study is aimed at the analysis of the pyrolysis kinetics of Nanche stone BSC (Byrsonima crassifolia) as an agro-industrial waste using non-isothermal thermogravimetric experiments by determination of triplet kinetics; apparent activation energy, pre-exponential factor, and reaction model, as well as thermodynamic parameters to gather the required fundamental information for the design, construction, and operation of a pilot-scale reactor for the pyrolysis this lignocellulosic residue. Results indicate a biomass of low moisture and ash content and a high volatile matter content (≥70%), making BCS a potential candidate for obtaining various bioenergy products. Average apparent activation energies obtained from different methods (KAS, FWO and SK) were consistent in value (~123.8 kJ/mol). The pre-exponential factor from the Kissinger method ranged from 105 to 1014 min−1 for the highest pyrolytic activity stage, indicating a high-temperature reactive system. The thermodynamic parameters revealed a small difference between EA and ∆H (5.2 kJ/mol), which favors the pyrolysis reaction and indicates the feasibility of the energetic process. According to the analysis of the reaction models (master plot method), the pyrolytic degradation was dominated by a decreasing reaction order as a function of the degree of conversion. Moreover, BCS has a relatively high calorific value (14.9 MJ/kg) and a relatively low average apparent activation energy (122.7 kJ/mol) from the Starink method, which makes this biomass very suitable to be exploited for value-added energy production.

Abstract This research explores optimal reaction conditions for the generation of gas products, through the slow pyrolysis of apple pomace, to be used as a feedstock for the production of H 2 by the absorption enhanced reforming of methane (AER). Pyrolysis was performed at 300–450 °C and heating rates 5–20 °C/min. Gases, tars and chars were quantified at different heating rates and isothermal conditions. Results indicate that at 400 °C a maximum of 71.5% W of non-condensable volatile matter (NCVM) can be obtained along with 25.4% W of condensable volatile matter (CVM), while only 3% W of residual matter (RM). At these conditions (NCVM) a gas composition of 49.8% CO, 26.8% CO 2 and 23.4% CH 4 (Vol) was generated. A thermodynamic analysis of this product gas was performed under AER through CO 2 absorption by CaO. Calculations using a steam to methane ratio of 3.5 and 3.5 mol of CaO/mol of CH 4 indicate that a maximum H 2 production is achieved at 715 °C containing 73.0% H 2 , 19.1% CO, 5.3% CO 2 and 2.5% CH 4 with no carbon formation.

Abstract Biomass waste-to-energy is an attractive alternative to fossil feedstocks because of essentially zero net CO 2 impact. A viable option consists in an integrated process, in which biomass is partly used to produce valuable chemicals with residual fractions employed for hydrogen production. One example of a biomass waste is the apple pomace, which is the residue generated in the process of extraction of apple juice. In this research, a kinetic study of the pyrolysis of apple pomace biomass (APB) was performed by TGA aiming its liquid and gaseous products be utilized for the production of valuable chemicals and hydrogen. Characterization of APB consisted in calorific value, compositional, proximal and elemental analyzes. Kinetics were evaluated using three iso-conversional TGA models at 5, 10, 15 and 20 °C/min. Activation energy values of 213.0 and 201.7 kJ/mol were within the range for hemicellulose and cellulose, respectively, which are the main components of biomass.