Numerical Simulation Of Chemical Looping Combustion Using An Iron Ore As Oxygen Carrier In A Pilot Scale Unit

As a new type of carbon capture technology,chemical looping combustion has the advantages of low energy consumption and inherent separation of CO₂,so it has a wide development prospect.In this paper,the characteristics of gas solid flow and the chemical reaction in the fuel reactor and air reactor are simulated.The results are as follows.The effects of the gas velocity at the inlet and the diameter of oxygen carrier particle on the characteristics of cold fluidization in the fuel reactor and air reactor are simulated.The results are as follow:in the fuel reactor,with the increase of gas velocity at the inlet,both of the volume of bubble and the height of bed will increase,and the change of pressure drop of gas has no obvious rule,but the fluctuation of pressure drop of gas will increase,also the velocity of gas and oxygen carrier particles will increase slightly;with the increase of particle diameter,all of the volume of bubble,the pressure drop of gas,the velocity of gas and oxygen carrier particles will decrease.In the air reactor,with the increase of gas velocity at the inlet,the oxygen carrier particles will fly out of the reactor quickly so that the concentration of oxygen carrier particles in the reactor will decrease,so the pressure drop of gas will decrease and the gas velocity will increase;with the increase of particle diameter,the oxygen carrier particles are easy to aggregate,and the pressure drop of gas will increase,but the change rule of gas velocity in different regions is different,also the velocity of oxygen carrier particles will increase in some regions due to the collision between particles.The effects of temperature,gas velocity at the inlet,and the concentration of fuel gas on the chemical looping combustion process in fuel reactor and the effects of temperature and gas velocity at the inlet on chemical looping combustion process in the air reactor are simulated.The results are as follow:in the fuel reactor,high temperature will accelerate the reaction rate,so the fuel conversion rate will increase;when the gas velocity at the inlet increase,the volume of bubble will increase,and the fuel conversion rate will reduce;when the fuel gas concentration change,the fluidization characteristics will be different,and changing the concentration of H₂ has less effect on the conversion of H₂,but while increasing the concentration of CO,some CO may not be consumed completely,so it will flow out of the reactor,then the conversion rate of fuel will decrease.In the air reactor,increasing the temperature can increase the oxidation rate of the oxygen carrier and make the oxygen carrier carry more oxygen in the same time.And with increasing the gas velocity at the inlet,the time for the oxygen carrier particles flying out of the reactor is shorter,and the change of the gas velocity at the inlet has little effect on the consumption rate of oxygen.