Characteristics of Coal Partial Gasification on a Circulating Fluidized Bed Reactor

Abstract

Experiments of coal partial gasification are conducted on a self-designed circulating fluidized bed (CFB) gasifier. The CFB gasifier system consists of a furnace, coal-feed system, air-feed system, steam generation system, gas–solid separation system, temperature- and pressure-measuring system, and material-returning system. The furnace is surrounded with electric heating wires, and the height and diameter of the furnace are 2600 and 120 mm, respectively. The experiments are conducted at temperatures between 885 and 980 °C. The coal particle size of 0.35–0.9 mm is chosen for experiments. The coal particle is gasified in the mixture of O2 and steam. The effects of different oxygen/coal ratios and steam/coal ratios on the performance of coal partial gasification are studied. As the results show, a higher oxygen/coal ratio leads to a higher gasification temperature and carbon conversion, while a slightly higher steam/coal ratio is better for the quality of syngas. The results show that the volume fraction of combustible gas and the lower calorific value reach as high as 70% and 9.1 MJ/Nm3, respectively. It can be obtained from the results of Raman and Fourier transform infrared spectra that the structure of chars becomes higher ordered as the different functional groups are gradually consumed. The chars become less reactive because higher ordered results in less reactivity.

Distribution Characteristics of Coking Products and Mechanism of Tar Lightening in Preparation of High-Strength Gasification-Coke with Low-Rank Coal Blending

“…Staged conversion of low-rank coal has attracted significant interest to improve the efficiency of energy utilization; one of the approaches is to enhance the quality of pyrolysis gas and tar, as well as the commercial value of coke. , In general, solid products (coke) produced during pyrolysis are used to generate electricity by combustion due to their low strength and easy pulverization . Thus, the formation of value-added chemicals and coke has become the focus during the staged conversion of low-rank coal.…”

Unique Advantages of Gasification-Coke Prepared with Low-Rank Coal Blends via Reasonable Granularity Control

“…Blending much low-rank coal with little caking coals to produce lump gasification-coke is a feasible approach to solve it and can realize the utilization of low-rank coal resources. 2 The conventional blending coking method failed to produce qualified gasification-coke when blending more than 40% low-rank coal with a little amount of caking coal in our previous work. 3 Moreover, the briquette from pulverized lowrank coal by adding coal-tar pitch or other binders often faces a pulverization problem in the moving bed gasification.…”

“…However, shortage of lump feedstock restrains the development of pressured moving bed gasification. Blending much low-rank coal with little caking coals to produce lump gasification-coke is a feasible approach to solve it and can realize the utilization of low-rank coal resources . The conventional blending coking method failed to produce qualified gasification-coke when blending more than 40% low-rank coal with a little amount of caking coal in our previous work .…”

Techno‐Economic Analysis of a Coal Staged Conversion Polygeneration System for Power and Chemicals Production

“…With a history of around 60 years, CFB combustion technology is one of the most promising commercial clean coal utilization technologies, with the advantages of good adaptability to coal types , strong load regulation capacity, and low pollutant emission. A 2 × 660 MW SCCFB power plant is selected as the configured power plant and for comparison.…”