Study On Depth Removal Of H₂S In Gas By High Gravity Method

Coke oven gas(COG)is one kind of the vital gas fuel with high calorific value,which can be used in either civil or industrial fuels,such as synthesis of methanol,ammonia and LNG COG must be purified prior to use and the removal process of H2S is particularly vital.Due to more strict environmental regulations and requirements of raw materials,the H2S content in COG through the traditional wet desulfurization process cannot meet the emission standard and requirements for the further depth processing.Therefore,it is necessary to develop a new technology for depth desulfurization from COGIn this work,Na2C03 solution containing PDS-600 catalyst was adopted as absorbent for H2S removal in a rotating packed bed(RPB).The effects of rotation speed of rotor,Na2CO3 concentration,liquid flow rate,gas flow rate,inlet H2S concentration on H2S removal efficiency were studied,and the operation mode of gas-liquid concurrent contact was explored.In view of the absorption results of Na2CO3 solution and actual plant operating data,simulated lean solution with specific concentration was chosen to remove H2S in the RPB.The overall gas phrase volumetric mass-transfer coefficient(KGa)was also deduced and the effects of various factors,including Na2CO3 concentration,liquid flow ratio,inlet H2S concentration,rotation speed and gas flow,were studied.Furthermore,the regeneration of rich solution in RPB was explored.The results indicated that the H2S removal efficiency can reach above 99%with outlet H2S concentration lower than 5 ppm under the operation conditions of rotation speed of 1400 rpm,Na2CO3 concentration of 6.0 g-L-1,H2S inlet concentration of 300 ppm and liquid gas ratio of 5-7 L-m-3.Additionally,the outlet H2S concentration can be lower than 15 ppm with suitable operation conditions when simulated lean solution was used.Under the similar operation conditions,the pressure drop and desulfurization performance with gas-liquid concurrent operation are lower than that with gas-liquid countercurrent operation,the desulfurization performance can also achieve the similar value when higher rotor speed and liquid flow rate are used.It can be seen that the low pressure drop is the main advantage for gas-liquid concurrent operation.In addition,KGa firstly increased and then keep constant with the increase in liquid flow rate,gas flow rate and Na2C03 concentration,and it firstly increased and then decreased with the increase in rotation speed and inlet H2S concentration.An empirical correlation of KGa was developed on the basis of experimental results and the calculated results agreed with experimental data well with a deviation within 15%.During the regeneration process,the concentration of HS-in the rich liquid was analyzed by Zinc Acetate Heating Method in view of the comparison results of different iodometric methods.The orthogonal experimental results showed that the significance of the factors affecting the regeneration performance was as following:liquid flow>gas flow>rotation speed...