Study On Flow Characteristic And Natural Gas Decarbonization In Rotating Packed Bed With Split Packing

Rotating packed bed is a new gas-liquid contacting reaction equipment.The internal packing of high rotational speed could produce centrifugal force field,which strengthened the gas-liquid mixing and accelerated the speed of interface between gas and liquid update to greatly enhance gas-liquid mass transfer.Rotating packed bed has the advantages of small equipment size,high treating efficiency,wide operational flexibility,low energy consumption and easy moving.It is widely applied and studied in chemical,environmental protection and energy sources field.Natural gas act as a clean,safety and high calorific fossil energy,its traditional purification process was generally carried out in the tower.But the huge equipment brought much inconvenience to the purification process.A lot of advantages of rotating packed bed made it more promising in natural gas purification process.In this paper,a set of rotating packed bed of natural gas decarbonization was designed and constructed.And the experiment with rotating packed bed and its application of natural gas decarburization was carried out to study the characteristic of equipment and the effect of technological parameters on decarburization.The experiment of gas pressure drop in rotating packed bed with split packing was carried out with air-water system.The effects of rotational speed,gas flow rate,liquid flow rate and different packing structure on the pressure drop of dry bed and wet bed were studied.The results showed that the gas pressure drop of dry bed and wet bed increased with increasing the rotational speed and the gas flow rate.The effect of liquid flow rate on pressure drop of wet bed was quite modest.The influence degree of three experimental factors on pressure drop of wet bed was,in order,gas flow rate,rotational speed and liquid flow rate.The flow characteristic of rotating packed bed with split packing was simulated by establishing a two dimensional model.And the numerical simulated values of gas pressure drop was in good agreement with experimental datas.At the same time,the liquid distribution in rotating packed bed with split packing was simulated by self-built geometrical model of porous packing.The effects of rotational speed and liquid flow rate on liquid distribution and liquid rending effect were studied.The simulated results showed that the liquid had better rending effect and more uniform distribution in high rotational speed.The absorption characteristic of carbon dioxide in ethanolamine,diethanolamine and N-methyldiethanolamine aqueous solution were tested by using the static absorption method.Which acted as a reference for selecting the absorbent for natural gas decarburization in rotating packed bed with split packing.The effects of the concentration and temperature of absorbent and initial pressure of reation system on absorption capacity and absorption rate of carbon dioxide were measured.The experimental results showed that the absorption capacity of N-methyldiethanolamine was the largest and the absorption rate of ethanolamine was the fastest in three kinds of absorbent.The high rotational speed of rotating packed bed shortened the residence time of the liquid,so the ethanolamine with faster absorption rate was more suitable for the decarburization process in rotating packed bed.The effects of rotational speed,gas-liquid ratio,temperature and concentration of absorbent on removal efficiency of carbon dioxide and gas volumetric mass transfer coefficient were measured by using ethanolamine as absorbent for natural gas decarburization in rotating packed bed with split packing.The experimental results showed that the removal efficiency of carbon dioxide and gas volumetric mass transfer coefficient increased with increasing the rotational speed and then remained unchanged.The optimum rotational speed was in the range of 1000~1200 r/min.The removal efficiency of carbon dioxide decreased with increasing the gas-liquid ratio and the gas volumetric mass transfer coefficient increased firstly and then decreased with increasing the gas-liquid ratio.The temperature of absorbent had little influence on removal efficiency of carbon dioxide and gas volumetric mass transfer coefficient in the experimental rang.The removal efficiency of carbon dioxide increased firstly with increasing the amount of substance concentration of ethanolamine and then remained unchanged.The gas volumetric mass transfer coefficient increased with increasing the amount of substance concentration of ethanolamine.The 1.5 mol/L ethanolamine was more suitable for this decarburization process.