Enriched‐Air Gasification of Refuse‐Derived Fuel in a Fluidized Bed: Effect of Gasifying Conditions and Bed Materials

Abstract

Enriched-air gasification of refuse-derived fuel (RDF) was carried out in a fluidized bed, investigating the effects of temperature, equivalence ratio (ER), oxygen percentage of enriched air (OP), and bed materials. For the bed material effect, calcined dolomite proved to be more effective for tar decomposition and resulted in higher CO and H 2 contents. In a bed of high-alumina bauxite, an increased ER tended to cause a greater decrease in syngas quality. For both bed materials, a higher temperature and OP favored the production of combustible gas and led to higher cold gas efficiency. Increasing the ER resulted in higher gas yields and carbon conversion but lowered the concentration of the combustible component. The ash content of the char increased with temperature and OP, while the volatile and fixed carbon contents were decreased. The optimum conditions suggested in this study were an ER of 0.22 and an OP of 44.7 % at 750-800°C in a bed of calcined dolomite.

Steam/oxygen biomass gasification at pilot scale in an internally circulating bubbling fluidized bed reactor

“…In fact, the availability of such a fuel gas can enable the use of smaller and cheaper internal combustion engines. Moreover, the availability of a technology based on enriched-air gasification can make it suitable for RDF gasification [37,38], thus expanding the fields of its applicability. Studies on low cost technology for oxygen-enriched air production are giving an important sustenance to the feasibility of such applications [39][40][41][42].…”

Oxygen-Enriched Gasification of Dried Sewage Sludge, Refuse-Derived Fuel, and Their Cogasification in a Laboratory-Scale Fluidized Bed

“…For both RDF and DSS, Figures 2a and b show that the CO and H 2 levels in syngas exhibited the same trends, i.e., continuous increases as the temperature rose from 650 to 800 °C; the CO 2 level trended in the opposite direction. Thus, following Le Chatelier's principle, a temperature increase enhanced endothermic reactions, including pyrolysis, oxidation, and the Boudouard, water−gas shift, and tar thermal cracking reactions; 16 thus, more CO and H 2 were generated. The CH 4 concentrations in producer gas from both RDF and DSS were maximal (7.59% for RDF and 8.56% for SDD) at 750 °C, perhaps reflecting the balance between CH 4 consumption via the steam−methane reforming reaction and oxidation and CH 4 generation via pyrolysis and tar thermal cracking.…”

“…27−30 Bed material enriching Al 2 O 3 may decompose tar, prevent slagging, and improve gas quality. 16 What's more, compared with calcined dolomite and olivine, high alumina bauxite was the best bed material for enriched-oxygen gasification due to its highest low heating value, gas yield, and gasification efficiency. 31 Therefore, in this study, the bed material is high-alumina bauxite, and its physical characteristics and chemical composition are shown in Table S1.…”

“…However, the dilution effect of nitrogen results in the production of a syngas with a low heating value (LHV) (about 4–6 MJ/Nm 3 ). , Using oxygen as the gasification agent not only increases the syngas LHV, to about 10–18 MJ/Nm 3 , but also the H 2 /CO ratio, which is important for producing liquid fuels via Fischer–Tropsch synthesis or when H 2 is required . However, the use of pure oxygen requires a complex system associated with a high capital cost; therefore, oxygen-enriched gasification (use of a gaseous mixture with a higher oxygen content than air as the gasification agent) has attracted a good deal of interest. − …”

Characterization of ash melting behaviour at high temperatures under conditions simulating combustible solid waste gasification

“…Enriched air with oxygen concentration of 44.7% was used as the gasifying agent and the gasification temperature was 800°C with an equivalence ratio of 0.2. The fluidized bed gasifier has been introduced in our previous work (Niu et al, 2014). GA collected from CSW gasification was stored in a drying vessel and then dried at 105°C for melting tests.…”