Solar cracking of methane is a promising technology for emission free hydrogen production. One of the major problems affecting methane cracking solar reactors' performance is the carbon particle deposition on the window, walls, and at the exit. In present study, a Lagrangian particle dispersion model has been implemented for predicting the particle deposition on the window of a seeded solar thermal reactor. A three-dimensional Computational Fluid Dynamics (CFD) analysis using Discrete Phase Model (DPM) has been done for qualitative validation of the experimental observations. In order to evaluate the turbulent quantities in the solar reactor; RNG k-ε model has been applied. Species transport has been solved by taking the gas for window screening as different from that used in the main flow. In addition, this paper presents a thorough parametric study predicting the particle deposition on reactor window for various flow configurations and flow conditions, which can be summarized as; (1) when the inlet flow angle is smaller, higher tangential velocities or swirl strength is obtained, (2) higher tangential velocities help in maintaining a stronger swirl, which keeps the screening flow close to the reactor window, (3) by increasing the main flow and the screening flow rates, the particle deposition on window is reduced, (4) when a lower density fluid is used as window screening gas, the particle deposition is reduced because the Taylor instabilities are avoided. The CFD work and the findings presented in this paper would be used as a guide in designing a solar reactor or improving the configuration of existing reactor.
Bibliographical noteFunding Information:
This research has been funded by Texas A&M University at Qatar. We would like to express our deep appreciation to Professor Abraham Kogan of the Weizmann Institute of Science Solar Facilities Unit for his invaluable assistance and constructive feedbacks during the course of this research which was completed during the time of his health. We wish him farewell on his next journey to the world beyond, which he took on September 7, 2009. We would also like to thank to Khalid Warraich and Faisal Chaudhry of TAMU-Q for their assistance with the supercomputing facilities.
- Carbon deposition
- Methane cracking
- Solar reactor