Gasification of Natural and Waste Biomass in a Pilot Scale Fluidized Bed Reactor

Abstract

Three commercially available biomass fuels, made of natural and waste wood, were fed in a pilot scale bubbling fluidized bed gasifier having an internal diameter of 0.381 m and a maximum feeding capacity of 100 kg/h. The experimental runs were carried out at about 850 C and under values of the equivalence ratio between 0.20 and 0.30. The fluidized bed was generally made of natural olivine even though some runs utilized beds of dolomite or quartz sand. Measurements taken during each run include the gas composition, the content of tar in the syngas, the mass flow rate and composition of entrained fines collected at the cyclone and the characterization of bed material. The results indicate that the air gasification process is technically feasible with all the biomass tested. The olivine as tar removal bed catalyst provides for different results with waste and natural biomass fuels.

Olivine as a tar removal catalyst during fluidized bed gasification of plastic waste

“…21 On the other hand, an increase in equivalence ratio is obviously limited by the need to obtain a sufficiently large heating value of the gas: the possible strong decrease in total tar content (see runs 5, 6, and 7 in Table 1) is, however, accompanied by an increase in tar dewpoint, related to the increase in heavy PAH compounds. 12,28 The use of olivine as an active bed additive inside the gasifier was suggested by the promising results obtained in fluidized bed biomass gasifiers operated with a bed of natural olivine. 12,14,15,20,32 The measurements made in air-gasification runs with recycled PE injected in a bed of olivine particles indicated a high quality of the produced gas, in terms of low tar content, large syngas yield and high hydrogen volume fraction (Table 1).…”

Fluidized-Bed Gasification of Plastic Waste, Wood, and Their Blends with Coal

“…Gasification is a viable technology for the thermo-chemical conversion of biomass and wastes due to its greater environmental sustainability and to the production of valuable products from different fuels. Among all gasification technologies, fluidization is often chosen as a reference for its great operating flexibility: the good mixing properties that ensure uniform process conditions, while also simultaneously feeding different fuels; the possibility to utilize various fluidizing agents [1][2][3][4]; to operate with or without a specific bed catalyst [5][6][7][8][9][10]; to add reagents along the reactor height [11][12][13][14], and to feed fuels in different positions of the reactor [15][16][17]. On the other hand, during the gasification process, the unavoidable formation of contaminants such as tar, carbonaceous particles, and inorganics leads to an increase in operating costs and efficiency loss.…”

Energy recovery from plastic and biomass waste by means of fluidized bed gasification: A life cycle inventory model

“…These data derive from hundreds of hours of operation of the FBG over 10 years, by feeding 10 different waste and biomass fuels [32][33][34][35][36][37][38]. The inventory model has been implemented in the EASETECH LCA model and applied to selected case-studies scenarios to illustrate applicability.…”