Thermodynamic modelling and optimization of oxy-reforming and oxy-steam reforming of biogas by RSM

In this study, a comparative thermodynamic equilibrium calculation of biogas oxy-reforming and oxy-steam reforming processes to produce syngas has been conducted by Aspen Plus simulation software. The effects of temperature (600-800°C), pressure (1-20 atm), and inlet O₂/CH₄ (0-1.0), H₂O/CH₄ (0-3.0), and CO₂/CH₄ (0.3-1.0) mole ratios on the equilibrium compositions of products were determined. The operation of the process was optimized using Gibbs free energy minimization method and statistical approach: response surface methodology (RSM). Optimum operating conditions CH₄/CO₂/O₂= 1:0.51:0.12 at 788°C and 1 atm for oxy-reforming and CH₄/CO₂/H₂O/O₂= 1:0.63:0.19:0.07 at 780°C and 1 atm for oxy-steam reforming were obtained to reach maximum H₂ yield, CH₄ and CO₂ conversions by minimizing carbon selectivity to produce syngas for methanol production.

A novel process for CO2 capture by using sodium metaborate. Part I: effects of calcination

This paper presents a comprehensive study on the carbonation of sodium metaborate (NaBO₂) and the synthesis of high added value chemicals via NaBO₂ and carbon dioxide (CO₂). Carbon dioxide (CO₂) is a greenhouse gas and NaBO₂ is a by-product of sodium borohydride (NaBH₄) hydrolysis reaction to produce H₂. Therefore their transformation into commercial chemicals is quite important in order to provide a mutual benefit to global warming issue and hydrogen economy. In the presented study, reaction parameters such as hydration factor, furnace type, calcination temperature, and environment are investigated at different levels and optimized. The effects of those key parameters on CO₂ fixation yield are discussed. It is found that 400 °C is a key temperature for dehydration and reaction steps. Both dehydrated NaBO₂ is obtained and maximum carbonation conversion is reached at 400 °C. Moreover, at relatively low temperatures (below 400 °C), a new reaction pathway is proposed and proved by thermodynamic calculations. Structural properties of NaBO₂ are exhibited differences regard to thermal exposure and the conversion is strictly related to the structural properties.