The Simulation Of Utilization Of Low Rank Coal By TBCFB Technology And Recovery Of Phenol From Wastewater

Triple-bed circulating fluidized bed(TBCFB)as a new type of fluidized bed unit,which is composed of a downer,bubbling fluidized bed,a riser.The three parts completed the process of pyrolysis,gasification and combustion.The biggest characteristic of this technology is combined endothermic reaction(pyrolysis and gasification)and exothermic reaction(burning),and solid heat carrier is used to transport the heat generated by the endothermic reaction to the downer and gasifier to support the exothermic reaction.This thesis use Aspen plus software,which provides powerful material database and the thermodynamic model,to analysis the heat balance and material balance of Triple-bed circulating fluidized bedprocess.Because of the lack of related hot state experimental data,it is necessary to assume that the reactor temperature,specific as follows:1.In downer reactor,the temperature of heat carrier is 1100 ? near the inlet,which is 900 ? near the outlet.the temperature of feedstock is 200? near the inlet,the temperature of char is 650 ?;2.In bubbling fluidized bed reactor,the temperature of heat carrier is 900? near the inlet,which is 850? near the outlet,the temperature of char is 850 ? near the outlet,the temperature of steam is 800 ?;3.In combustion reactor,the temperature of heat carrier and char near the inlet is 850 ?,the oxygen temperature is 100 ?,the temperature of heat carrier is 1100 ? near the outlet.The results show that when char is circulating heat carrier,the optimal mass ratio of char to coal is 6.5:1.When the quartz sand is circulating heat carrier,the optimal mass ratio of quartz sand to coal is 12.5:1.When the feedstock is 100 kg/h of low rank coal,bubbling fluidized bed gasifier need 5.4 kg/h of steam,combustion process need 50 kg/h of oxygen.According to simulation,the yield of the tar was 20.5%,the yield of gas was 52.8%,the yield of char is 26.7%.At the same tiome,7% of char is used for gasification,93% of char is used for combustion.The follow-up of Triple-bed circulating fluidized bed process inevitably need to purify phenol wastewater.in This thesis,Aspen plus V7.3 software is used to simulate pervaporation-fractional condensation(PVFC)technology treatment process of phenol waste water.The results shows that at-8 ? of condensing temperature,97.23% of phenol with 80.6% of purity can be recovered Property analysis tools are used to draw phase diagram of phenol/water.It is found that the phase diagram is almost "right triangle" at 280 Pa of pressure.According to the Antoine equation calculation,,phenol and water' saturated vapor pressure in this low pressure are 3.16 Pa and 3.16 Pa respectively,while the actual pressure of phenol and water is 23.24 Pa(> 3.16 Pa)and 3.16 Pa(< 334.8 Pa)respectively.Thus,only phenol can be condensed.This is the reason that PVFC process can obtain high purity phenol.