Experimental Study On Preparation Of Sulfur Impregnated Porous Activated Carbon And Its Performance On Natural Gas Mercury Removal

Recently,natural gas is used as a renewable energy source in the fields of power generation,chemical,and urban gas.However,the existence of mercury can rise damage to human health,aluminum equipment,and the ecological environment during natural gas extraction and transportation.Mercury is toxic,persistent,bioaccumulative,and long-range transportable.It can deteriorate aluminum equipment and may result into pressure reduction of vessels,leakage of pipelines,and explosions.Therefore,achieving efficient and economical purification of mercury-containing natural gas has turned into one of the urgent problems to be solved in the development of natural gas recycling.In industry,activated carbon is often used as an adsorbent for mercury removal from natural gas.According to porous framework of the activated carbon,the activated carbon was modified by sulfur in the experiment,and the mercury adsorption efficiency of the adsorbent was evaluated by a mercury adsorption device.The experiment in this study mainly consists of high-temperature sulfurization and supercritical fluid deposition to prepare sulfur impregnated porous activated carbon.The main influencing factors for high-temperature sulfurizing experiment are impregnation time,impregnation temperature,and ratio of sulfur to carbon.The latter mainly includes temperature,pressure,impregnation ratio and co-solvent.The results show that:Using high-temperature sulfur impregnation experiment for the synthesis and application of sulfur impregnated in porous activated carbon for elemental mercury removal from natural gas using a fixed-bed reactor.Experimental processes were conducted to investigate the optimization of Hg~0 adsorption.Furthermore,our experimental results about optimum conditions for removing Hg~0 were 1:10 of sulfur to activated carbon impregnation ratio,350°C of impregnation temperature,and 3 hours of impregnation time.The high temperature changes the surface activated carbon properties and forms new active adsorption sites.At first,as the impregnation temperature gradually increases,the adsorption capacity increases,the adsorption capacity decreases when the temperature is higher than 500°C.This research showed that the prepared adsorbents were capable to remove remarkable amount of Hg~0(23.615 mg/g)at high adsorption efficiency.This study may serve as reference on natural gas power plants for the removal of Hg~0 using the same conditions.In the supercritical experiment,both pressure and temperature have a great influence onthe tested samples.Where the optimized prepared adsorbent obtained at 12.5MPa and the temperature is at 40~80°C,and the adsorption capacity is better.The carbon disulfide solution is a co-solvent that promotes sulfur to get doped in the pores of the activated carbon and improves the sulfur loading efficiency.