Research On The Process Of Removing Low-concentration H₂S From Natural Gas By Modified Activated Carbon

With the development of the technology of removing hydrogen sulfide from natural gas,Purification treatment of natural gas with high content of hydrogen sulfide has been relatively mature.For the purification of natural gas with low hydrogen sulfide content,there are various problems in the existing desulfurization technology.Therefore,it is very important to find a new and renewable dry desulfurization technology to solve the low gas content,low H2S content and the remote natural gas.Activated carbon is a kind of artificial porous materials.Characteristic of high specific surface area,pore structure and crystallite structure make it have better adsorption performance.It is not pulverized when encountering water,cheap and easy to regenerate and so on,has been widely used in the field of sewage and waste gas treatment.However,the adsorption capacity of activated carbon to H2S is weak,therefore,it is needed to load some catalysts to improve the catalytic activity of activated carbon.This paper examines performance of the activated carbon on the adsorption of H2S,Using activated carbon as the carrier,it were individually loaded with NaOH,CoPC,CoPcS and at the same time by impregnation method,through the experiment we obtained the saturation sulfur capacity and breakthrough time of each desulfurization sorbents.The experimental results show that the breakthrough time is 180min when loading NaOH,while the CoPc and CoPcS can promote the removal of H2S,but the difference between saturated sulfur content and unmodified activated carbon is not quite different.When loaded with 10%NaOH and 0.3%of CoPcS,the maximum penetration time was 280min,When loaded with 10%NaOH and 0.25%CoPc,the maximum penetration time of removal of H2S is 240 min,which can see the catalytic effect of CoPcS is better than CoPc.the blank activated carbon,activated carbon and sulfur saturated activated carbon went through the scanning electron microscope and EDS elemental analysis,got the result that the final desulfurization products of activated carbon is sulfur.Experiment research four influencing factors of relative humidity,temperature,oxygen and sulfur ratio and gas velocity on activated carbon desulfurization process,it is concluded that when relative humidity of activated carbon is 10%,the temperature is 333k and the ratio of oxygen and hydrogen sulfide is 3:1,volume space velocity is 1274h-1,the saturated sulfur capacity of the activated carbon is up to the maximum,the maximum saturated sulfur content is 32mg/g.According to the experimental results,when the flow rate of raw material gas is 10×104sm3/d,the temperature is 30? and the pressure is 4.2Mpa,cycle operation is 8h,each cycle need the volume of the activated carbon is 4.84m3,the area of the fixed bed is 1.12m2 and the bed layer height is 4.84 meters,pressure drop of fixed adsorption bed is 766.16Pa.