Catalytic Pyrolysis of Pinyon–Juniper Using Red Mud and HZSM-5

Abstract

Pinyon and juniper are invasive woody species in the western United States that occupy over 30 million hectares of land. The U.S. Bureau of Land Management (BLM) has embarked on harvesting these woody species to make room for range grasses for grazing. The major application of harvested pinyon–juniper (PJ) is low-value firewood. Thus, there is a need to develop new high value products from this woody biomass to reduce the cost of harvesting. We investigated the fractional catalytic pyrolysis of PJ using both HZSM-5 catalyst and red mud at 475 °C in a fluidized bed reactor at atmospheric pressure. Both the HZSM-5 and the red mud were effective catalysts for producing low-viscosity pyrolysis oils. Oils that were catalyzed with red mud had a lower viscosity (96 cP @40 °C) than oils that were catalyzed with HZSM-5 (213 cP @40 °C). In both cases, the yields of liquids ranged from 42 wt % to 49 wt %. The mechanisms of catalysis by the two catalysts were quite different. The HZSM-5 rejected oxygen mostly as carbon monoxide (CO) and produced lower amounts of carbon dioxide (CO2); in contrast, the red mud produced more CO2 and less CO. However, both catalysts produced similar amounts of water. The char/coke yields from both catalysts were similar but the total gas yields were slightly different. The higher heating value of the red mud catalyzed oil (HHV = 29.46 MJ/kg) was slightly higher than that catalyzed by HZSM-5 (HHV = 28.55 MJ/kg). Thus, red mud can be used to achieve similar catalytic pyrolysis results as HZSM-5 catalysts.

Pyrolytic Conversion of Olive Mill Wastewater Sludge to Biofuels Using Red Mud as Catalyst

“…The change in properties of the red mud was attributed to the conversion of hematite (Fe 2 O 3 ) to magnetite (Fe 3 O 4 ) under the reducing pyrolysis conditions. This transformation of red mud after pyrolysis was described in detail in Yathavan and Agblevor [35].…”

“…[13]The red mud water slurry had a pH 9 and the dry ground material used for the experiments had a BET specific surface area 30 [35]. The presence of these oxides was further confirmed with XRD analysis.…”

“…The mechanism of liquid formation using the red mud was quite different from that due to the thermal process on the silica sand. Whereas the silica sand cracked the organic liquids to gases with minimal dehydration of the oxygenated compounds, in contrast, the red mud appeared to produce both pyrolytic water and gases from the cracking of the organic liquid through decarboxylation, ketonization, and decarbonylation reactions Yathavan and Agblevor [35].…”

“…In general catalytic pyrolysis tends to decrease the yield of liquid products because of cracking of the organic fraction [35][36][37][38][39], the same decrease in liquid yield was observed in these studies, but the decrease appeared to be less severe compared to woody biomass pyrolysis using HZSM-5 zeolite and red mud catalysts Yathavan and Agblevor [35] The temperature increase appeared to have minimal effect on the production of pyrolytic water from the organic liquids by the sand, instead it produced some gases. In contrast, the red mud pyrolysis converted a large fraction of the organic liquid products into pyrolytic water and thus reducing the organic liquid yield.…”

Production of Pyrolysis Oil with Low Bromine and Antimony Contents from Plastic Material Containing Brominated Flame Retardants and Antimony Trioxide

“…RM, CL and NZ were industrial solid wastes or natural mineral. Because of their low-cost, high metal oxides content and catalytic cracking properties, they were frequently applied as catalysts or additives for the pyrolysis of biomass and plastics (Yathavan & Agblevor, 2013;Lópeza et al, 2011;Lee, 2001;Zhang, Zhang, Yang & Yan, 2014). In this study, in order to investigate the effect of RM, CL and NZ additives on the degradation of Br-HIPS and the debromination characteristic, the pyrolysis experiments were carried out in presence of each additive at the pyrolysis temperature of 500℃.…”