Showing papers by "P.K. Tewari published in 2016"

Study of Bunsen reaction in agitated reactor operating in counter current mode for iodine-sulphur thermo-chemical process

Abstract: The iodine-sulphur (IS) thermo-chemical process is being studied as a potential process for production of hydrogen by water splitting. It consists of three chemical reactions: 1) Bunsen reaction, which is the acid production step, 2) sulphuric acid decomposition to produce oxygen; 3) hydrogen iodide decomposition to produce hydrogen. In this work, a detailed parametric study of the Bunsen reaction is presented, which was carried out in agitated reactor (ABR) in counter current mode of operation. Experiments have been carried out in the reactor at different temperatures by varying the sulphur dioxide (SO2) flow rate and partial pressure of SO2. Bunsen reaction rate and SO2 conversion are calculated experimentally from feed rate and scrubbing rate of SO2. It has been observed that the reaction rate and SO2 conversion increase with increase in SO2 flow, increase in SO2 partial pressure and decrease in temperature. 'Tanks-in-series' model, one of the non-ideal reactor models, has been proposed to describe the ABR reaction system. The model has been validated with experimental results. This approach can be useful for the design and scaling up of the agitated reactor.

Effect of agitation speed and fluid velocity on heat transfer performance in agitated Bunsen reactor of iodine-sulphur thermo-chemical cycle

Abstract: Agitated Bunsen reactor (ABR) is one of the reactor alternatives to carry out Bunsen reaction of iodine-sulphur thermo-chemical process for hydrogen production. It is a tubular reactor with multiple agitating blades on a common shaft to enhance the radial mixing and with an inside helical coil arrangement to remove the exothermic Bunsen reaction heat. The effective heat removal from the reactor depends on the agitation speed and velocity of fluids flowing inside the reactor and through the helical coil. Experiments are carried out in ABR, for heat transfer study with water as reactor fluid as well as helical coil fluid and also Bunsen reaction heat transfer study, by varying the operating parameters such as agitation speed, velocity of reactor fluid and velocity of helical coil fluid. It has been observed that the overall heat transfer coefficient increases with increase in agitation speed and fluid velocities. Combined effect of agitation speed and fluid velocities on heat transfer rate, in shell side/reactor side of ABR, has been presented in the form of modified correlation.

Modelling of membrane reactor for hydrogen production by HI decomposition: studies on catalyst activity and non-isothermality in packed bed and coated wall configurations

Abstract: The objective of this work was to assess the impact of deviations from isothermality in packed bed and coated wall membrane reactors on the rates of HI decomposition. A two-dimensional modelling was done for a packed bed membrane reactor as well as a coated wall membrane reactor for HI decomposition. The smaller diameter reactor showed higher apparent catalyst activity. The reactivity results showed that the reactors suffered from significant temperature gradients. We estimated the diameter required for packed bed and coated wall membrane reactors to achieve near isothermal operation. The coated wall reactor gives lower conversion than the packed bed reactor. The model confirmed that the measured catalyst activities in different diameter reactors varied due to heat transfer and pressure drop effects.