DDR zeolite membrane reactor for enhanced HI decomposition in IS thermochemical process |
| |
Authors: | Nitesh Goswami Ankita Bose Nandini Das SN Achary AK Sahu V Karki RC Bindal Soumitra Kar |
| |
Affiliation: | 1. Membrane Development Section, Chemical Engineering Group, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India;2. Central Glass & Ceramics Research Institute, CSIR, Kolkata 700 032, India;3. Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India;4. Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India;5. Fuel Chemistry Division, Atomic Research Centre, Trombay, Mumbai 400085, India;6. Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India |
| |
Abstract: | The third section of closed loop Iodine Sulphur (IS) thermochemical cycle, dealing with HIx processing, suffers from low equilibrium decomposition of HI to hydrogen with a conversion value of only ~22% at 700 K. Here, we report a significant enhancement in conversion of HI into hydrogen (up to ~95%) using a zeolite membrane reactor for the first time. The all silica DDR (deca dodecasil rhombohedral) zeolite membrane with dense, interlocked structure was synthesized on the seeded clay alumina substrate by sonication mediated hydrothermal process. The synthesized membranes along with seed crystals were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDX). Corrosion studies were carried out by exposing the membrane samples to simulated HI decomposition reaction environment (at 450 °C) for different durations of time upto 200 h. The FESEM, EDX and XRD analyses indicated that no significant changes occurred in the morphology, composition and structure of the membranes. Iodine adsorption on to the membrane surface was observed which got increased with the exposure duration as confirmed by secondary ion mass spectrometry studies. A packed bed membrane reactor (PBMR) assembly was fabricated with integration of in-house synthesized zeolite membrane and Pt-alumina catalyst for carrying out HI decomposition studies. The tube side was chosen as reaction zone and the shell side as the permeation zone. The HI decomposition experiments were carried out for different values of temperature and feed flow rates. DDR zeolite based PBMR was found to enhance the single-pass conversion of HI up to ~95%. The results indicate that for achieving optimal performance of PBMR, it should be operated with space velocities of 0.2–0.3 s?1 and temperature in the range of 650 K–700 K with permeate side vacuum of 0.12 kg/cm2. It is believed that the in-house developed zeolite PBMR shall be a potential technology augmentation in making the IS thermochemical cycle energy efficient. |
| |
Keywords: | Membrane reactor Hydrogen IS thermochemical cycle DDR zeolite membrane HI decomposition |
本文献已被 ScienceDirect 等数据库收录! |
|