CO-GASIFICATION OF BLACK LIQUOR AND PULP SLUDGE FOR FUEL PRODUCTION

摘要

In this research, product distribution and energy efficiency from co-gasification of pulp sludge mixedwith black liquor has been suggested as a relatively new technology that can be used in addition to recovery boiler inthe chemical recovery process. This research was carried out in a fixed bed reactor. The operating parametersincluding temperature of 700, 800 and 900°C, equivalence ratio (ER) of 0.2, 0.4 and 0.6 and ratio of pulp sludge toblack liquor of 50:50 and 40:60 at feeding rate of 5 g/min were examined. In addition, Ni-La-Mg/Al_2O_3 catalyst wasprepared by co-impregnation method and mixed with raw material before feeding into system to study its effect onthermochemical conversion reaction. Major gaseous products such as CO, CO_2, H_2 and CH_4 were analyzed by TCDNDIRanalyzer. Char and tar residue were collected and calculated by measured weight. The results of non-catalyticcases indicated that the optimal condition was temperature of 900°C, ER of 0.2 and raw material ratio 40:60 with gasyield of 69.18%, H_2 to CO ratio of 0.96, lower heating value of 5.91 MJ/m~3 and cold gas efficiency of 79.55%. Forcatalytic cases, it was found that the catalyst can improve the percentage of gas yield around 10 wt%. Lower heatingvalue and cold gas efficiency of catalytic cases were 3.78-6.73 MJ/m3 and 46.02-90.13% while those obtained fromnon catalytic trials were 3.37-5.91 MJ/m3 and 34.63-79.55%, respectively. From these results, co-gasificationprocess can be considered as alternative option for conversion pulp sludge mixed with black liquor to usable fuelproducts.