Catalytic Steam Gasification of Pine Sawdust. Effect of Catalyst Weight/Biomass Flow Rate and Steam/Biomass Ratios on Gas Production and Composition

Abstract

Pine sawdust catalytic steam gasification has been studied in a fluidized bed at a relatively low temperature, 700°C. The Ni-Al catalyst used was prepared by coprecipitation and calcined at 750°C for 3 h. The influence of the catalyst weight/biomass flow rate (W/mb) and steam/ biomass (S/B) ratios on the product distribution and on the quality of the gas product obtained was analyzed. An increase of the W/mb ratio increases the total gas, H 2 , CO, and CO 2 yields, while CH 4 and C 2 yields decrease. An increase of the S/B ratio increases H 2 and CO 2 yields while CO and CH 4 yields decrease. This fact can be explained by steam reforming and water-gas shift reactions. The increase of the S/B ratio also has a positive effect on the life of the catalyst. The gas composition and gas yields at initial time have also been studied. For W/mb ratios > 0.5 h, the gas composition at initial time is similar to that for thermodynamic equilibrium for different S/B ratios. The influence of the S/B ratio on gas yield at initial time is more marked, up to a ratio of 1.5.

Promotion of Coconut Shell Gasification by Steam Reforming on Nickel-Dolomite

“…As temperature increased, more carbon and steam can be converted and favor the products in endothermic reactions (4). Therefore, a higher reforming temperature favor the conversion of tar and CH 4 into H 2 and CO and elimination of coke on catalyst decreased in CO 2 (5) and (6).…”

“…Steam is one of the most commonly used gasification agents because a high percentage of hydrogen can be obtained during the process. Many researchers have proved the usefulness and effectiveness of calcined dolomite and nickel based steam reforming catalysts on decreasing tar yield [3][4][5][6][7][8][9][10][11][12] . The catalyst can increase the reaction rate of the steam and can participate in the secondary reactions.…”

“…The catalyst can increase the reaction rate of the steam and can participate in the secondary reactions. Therefore, the catalyst improves the quality of the gas product and reduces tar content in the process [6] . Besides adding active bed materials also prevents agglomeration tendencies and subsequent coking of the bed.…”

Steam-Reforming Characteristics of Heavy and Light Tars Derived from Cellulose

“…Therefore, numerous investigations of tar formation, reforming, and cracking have been conducted. There is a substantial amount of literature that discusses tar characteristics by defining tar as the sole condensable matter collected in the tar trap (2)(3)(4)(5)(6)(7) ; however, the complex composition of biomass tars makes it difficult to understand the tar reaction mechanisms when tar is considered as the sole condensable matter. Therefore, some studies have used model tar compounds such as benzene (8) , toluene (9)(10) , and naphthalene (11) to clarify the tar decomposition mechanism.…”

“…Therefore, the formation characteristics of tars classified by condensing temperatures are also useful for developing a biomass gasifier. Steam gasification of biomass has been extensively studied in various reactors (2,5,10,15) ; however, the steam-reforming characteristics of heavy tar have not been clarified. Therefore, to better understand the mechanism of tar formation and steam reforming, the characteristics of heavy tar should be studied.…”