Modeling and Simulation
Malihe Heravi; Mahdi Bayat; Mohammad Reza Rahimpour
Volume 13, Issue 4 , November 2016, , Pages 71-95
Abstract
The main focus of this study is improvement of the steam-methane reforming (SMR) process by in-situ CO2 removal to produce high hydrogen content synthesis gas. Sorption-enhanced (SE) concept is applied to improve process performance. In the proposed structure, the solid phase CO2 adsorbents and pre-reformed ...
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The main focus of this study is improvement of the steam-methane reforming (SMR) process by in-situ CO2 removal to produce high hydrogen content synthesis gas. Sorption-enhanced (SE) concept is applied to improve process performance. In the proposed structure, the solid phase CO2 adsorbents and pre-reformed gas stream are introduced to a gas-flowing solids-fixed bed reactor (GFSFBR). One dimensional mathematical model is developed to evaluate the effect of adsorbents on the efficiency of SMR at steady-state condition. To prove the accuracy of the considered model, simulation results are compared against available industrial plant data. Modeling results represent that application of SE method in SMR enhances syngas production and reduces CO2 content. The reported data indicate that by overcoming thermodynamic limitations and controlling coke formation, CH4 conversion and H2 yield improve about 23% and 29%, respectively. For more investigation, sensitivity analyses of some related parameters of the pre-reformed gas are performed to predict optimum conditions. Finally, the proposed GFSFBR for the SMR process leads to higher hydrogen production and H2/CO ratio. As the last part, non-dominated sorting genetic algorithm-II is applied to perform multi-objective optimization of the SE-SMR.
Reaction Engineering, Kinetics and Catalysts,
Mahdi Bayat; M.R. Rahimpour
Volume 13, Issue 3 , July 2016, , Pages 3-18
Abstract
Nowadays, hydrogen and methanol are attractive prospects because of lower emission compared to the other energy sources and their special application in fuel cell technology, which are now widely regarded as key energy solution for the 21st century. These two chemicals also can be utilized in transportation, ...
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Nowadays, hydrogen and methanol are attractive prospects because of lower emission compared to the other energy sources and their special application in fuel cell technology, which are now widely regarded as key energy solution for the 21st century. These two chemicals also can be utilized in transportation, distributed heat and power generation and energy storage systems. In this study, a novel double fluidized-bed two-membrane reactor (DFTMR) is proposed to produce ultrapure hydrogen and enhance methanol synthesis as environmentally friendly fuels, simultaneously. The fluidization concept is used in both sides to overcome drawbacks such as internal mass transfer limitations, pressure drop, radial gradients of concentration and temperature in thermally coupled membrane reactors. The DFTMR system is modeled based on the two-phase theory of fluidization and then its performance is compared with those of thermally coupled membrane reactor (TCMR) and conventional methanol reactor (CR) under the same operating conditions. The simulation results show 24.69% enhancement in hydrogen production in comparison with TCMR. Furthermore, 14.39% and 15.78% improvement in the methanol yield can be achieved compared with TCMR and CR, respectively.