| With the sustainable and rapid development of national economy, oil security is being on the core position of Chinese energy strategy because of the shortage of petroleum resources in China and the abundance of low-rank coal resources, So the hydropyrolysis of coal will become a viable option for the production of fuel with abundant low-rank coals in China which products large amounts of coal tar,One of the most important pyrolysis products is phenols.Therefore, study on phenols yield and composition is of great significance for understanding the phenols mechanism.Effects of some conditions (such as pyrolytic temperature, reaction retention time, flow velocity of carrier gas, carrier gas pressuer and heating rate) on the yields and properties of hydropyrolysis products were systematically studied. Pingzhuang lignite was pyrolyzed first in fixed-bed equipment with hydrogen as carrier gas. The highest yield of tar under the optimum pyrolysis conditions is at 560℃, flow velocity of carrier gas 200SCCM,heating rate 6℃/min,gas presuer 2MPa, retention time 20min. the yield of tar reach 10.26wt%. The yield of total phenols has the maximum of 2.65wt% at 520℃. simple phenols have the higher yield than Complicated phenols when the temperature above520℃. However, the yield of Complicated phenols declined at the while temperature. Phenols are rich in tar, accounting for 17-26wt%.Pyrolytic temperature was studied on the composition of phenols in lignite tar obtained by DG process. The results show Phenols and tar have the maximum yield of 1.82wt%(d) and 7.58wt%(d) both at 510℃. Phenols are rich in tar, accounting for 20-35wt%, and among which simple phenols account for approximately 70wt%. The content of phenol accounts for approximately 30wt% of total phenols, Therefore, phenols will become one of the highly profitable products in DG process.Compared the two pyrolysis process, it shows that phenols from DG process have the higher economic results, though phenols from fixed-bed have the higher yield, phenols are richer in tar and simple phenols account for 70wt%from DG process which are much more useful than complicated phenols,it is worthy for extracting the simple phenols which are rich in the tar from pingzhuang lignite pyrolysis. |
