Preparation Of Coconut Shell-based Carbon Molecular Sieve For Air Separation

Carbon molecular sieve(CMS)is a porous carbon adsorbent,which is suitable for separating gases with different molecular sizes.The most common one is CMS for air separation.Therefore,the development of CMS production process is an important part in air separation field.Coconut shell is a raw material of biomass,which is cheap and easy to get.It is suitable to be used as the raw material of CMS.At present,there is no mature coconut shell-based CMS production technology at home.Therefore,it is urgent to develop CMS production technology which coconut shell is used as raw material.In this paper,three main processes(carbonization,activation and deposition)of coconut shell-based CMS production process were studied experimentally.In the two stages of carbonization and activation,comprehensive pore structure test and PSA test are used to explore the change law of the pore structure.It aims to provide a certain theoretical basis for the adjustment of the process parameters in the two stages of CMS production.In the carbon deposition stage,the two step method is used to prepare CMS by adjust pore structure.Besides,scientific and reasonable plans are proposed for the initial deposition and the second step.Two long time deposition plans(constant deposition agent dosage and constant deposition time)are proposed in the initial deposition stage for sedimentary adjustment.The performance of the two long time deposition plans is better than short time deposition plans,because the orifice scale can be more accurately regulated.Three kinds of scientific plans are put forward in the second adjustment process.By the low dose redeposition,the nitrogen production increased by 0.64 % and the nitrogen recovery increased by 5.47 %;by reactivating the hole,the nitrogen production increased by 9.10 % and the desorption gas increased by 3.42 L;by mixed deposition,the nitrogen production increased by 0.56 % and the nitrogen recovery increased by 6.83 %.