| Asphalt has a wide range of sources,high carbon content,low price,and a wide range of uses.It is often used in the preparation of mesophases,electrode materials,carbon fibers,activated carbon adsorbents,etc.The composition of asphalt is complex,and the analysis and separation of its different components can realize the refined utilization of asphalt.The separation of different components of asphalt is usually carried out according to the GB/T2292-2018 standard for the determination of toluene insoluble content in coking products and the GB/T2293-2008 standard for the test method for quinoline insolubles in coking asphalt products,but the solvent toluene used has toxic,easy to make poison,harmful to the environment,flammable and irritating,if used in large quantities in the extracted soluble matter,it is easy to cause harm to the environment.Therefore,it is necessary to find a solvent that can replace toluene to measure or extract the insoluble content of asphalt.Therefore,this project intends to use o-xylene instead of toluene as the solvent for the extraction of asphalt solubles.Preparation of mesophase and porous carbon materials.In this paper,coal tar pitch is used as the raw material,and various solvents such as toluene,o-xylene,and quinoline are used to separate their groups by dissolving and filtering.And use the obtained ortho-xylene soluble matter,quinoline insoluble matter and raw pitch to prepare mesophase pitch at different preparation temperatures and different holding times.Finally,using the obtained mesophase pitch as the precursor,potassium chloride as the template,and potassium hydroxide as the activator,the porous carbon was prepared by the template method,and its electrochemical properties were studied.The main conclusions are as follows:The coal pitch family fractions were first separated using toluene,o-xylene and quinoline and the results showed that both toluene soluble and o-xylene soluble contained more aliphatic compounds with more alkyl side chains,while quinoline soluble had a greater proportion of aromatic compounds;quinoline insoluble compounds contain more inert large particle impurities.The substitution of o-xylene for toluene in the separation of pitch family fractions is an effective and environmentally friendly method.The mesophase pitch was successfully prepared using o-xylene soluble and coal tar pitch.The results show that:increasing the thermal polymerisation temperature can effectively shorten the preparation time of mesophase pitch;at a certain temperature,extending the holding time can effectively improve the degree of thermal polycondensation reaction of mesophase pitch.The optimum processing temperature and time for the preparation of original mesophase carbon microspheres is 430℃ and 6 h.The optimum processing temperature and time for the preparation of mesophase carbon microspheres using o-xylene soluble material is 330℃ and 6 h.The use of o-xylene soluble material for the preparation of mesophase pitch can effectively shorten the mesophase pitch preparation temperature.Preparation of mesophase pitch into porous carbon materials using the template method.Electrochemical performance testing of prepared mesophase porous carbon materials,the results show that the electrochemical properties are related to the asphalt precursor.The porous carbon obtained from the mesophase prepared by holding the oxylene soluble material at 330℃ for 3 h had a specific capacitance of 102.5 F/g at a charge/discharge rate of 80 mA/g and 82.5 F/g at a charge/discharge rate of 800 mA/g,with maximum specific capacitance at different current densities,demonstrating good multiplicative performance.In addition,the specific capacitance of the o-xylene soluble mesophase porous carbon material was better than that of the unseparated mesophase asphalt porous carbon material at all current densities.The porous carbon obtained from the mesophase of o-xylene soluble material held at 330℃ for 3 h was prepared as a doublelayer capacitor and showed a very stable performance,with a retention rate of 99.7%of the initial specific capacitance after 500 cycles,but the power density and other properties were smaller and need further investigation. |
