Time-series analysis of pressure fluctuations in gas–solid fluidized beds – A review

Non-intrusive determination of bubble and slug length scales in fluidized beds by decomposition of the power spectral density of pressure time series

A critical review of the complex pressure fluctuation phenomenon in gas–solids fluidized beds

The uses of passive measurement of acoustic emissions from chemical engineering processes

Particle granular temperature in gas fluidized beds

The velocity of sound in fluidised beds

Abstract Using a newly developed experimental setup, the features and advantages of an autothermal single-casing atmospheric subbituminous coal fluidized bed air-blown gasifier, combining a combustion and gasification section, and mixing the dispersed phase (inert material, char) and heat exchange between them through an annular transfer device, have been revealed. To increase the efficiency of the gasifier, an experimental-computational method was developed find the conditions for optimal operation, combining changing the annular flow’s geometry and regulating the primary air for gasification. A simple and reliable multizone thermodynamic calculation model makes it possible to predict the composition of char and syngas in the gasification section with acceptable accuracy. This method confirmed that a two-section fluidized bed gasifier can provide efficient gasification of solid fuels and is suitable for use in small-scale cogeneration plants. Syngas with a heating value of 3.6–4.5 MJ/m 3 and CGE of 38.2%–42.3% was obtained in the experimental setup without optimizing the primary air flow rate. With optimization, the indicators increased to the heating value of syngas of 5.20–5.34 MJ/m 3 and CGE of 42.5%–50.0%. With heat regeneration of 0.8, CGE increases to 70%. 

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Investigation into the operation of an autothermal two-section subbituminous coal fluidized bed gasifier

Regarding medium- and low-temperature processes of heterogeneous heterophase interaction in the units for cleaning from pollutants and trapping CO2, the analogy of the behavior of standing surface waves of an ideal liquid with oscillations of the surface of a fluidized bed is considered. Waves on the surface of a fluidized bed are formed when gas bubbles leave it and are one of the elements of the mechanism of self-sustained fluctuations of the entire mass of the bed. The frequency modes of the surface waves correspond to the main modes in the spectra of pressure fluctuations in the bed and depend on its geometry. The fluctuations of a bubble three-dimensional fluidized bed in apparatuses of different sizes are numerically simulated in a high-performance parallel computing mode using the Ansys Fluent program. Comparison of analytical calculations for fluid oscillations in a vessel with the results of numerical simulation of a fluidized bed and experimental data on the frequency of the emergence of bubbles and modes of surface waves is carried out.

Parameters of surface standing waves in fluidized bed apparat with different diameter

The aim of this work is to study coal steam gasification with various methods of coal in-core treatment in FB using a newly developed thermodynamic calculation method. A calculational study of subbituminous coal steam non-catalytic gasification was carried out using four different methods of coal in-core treatment in single-vessel multisectional fluidized-bed gasifiers. A semi-empirical model based on the entropy maximization thermodynamic method and “restricted equilibria” based on previously obtained experimental data has been developed. Based on thermodynamic calculations, the effect of the leading thermochemical processes and operating parameters of the fluidized bed (temperature, fluidization number, steam/coal ratio feed rate) was revealed. New information was obtained regarding the composition of char and syngas at the gasifier outlet, the syngas heating value, and the cold gas efficiency of the steam gasification of Borodinskiy subbituminous coal char. The results indicate the possibility of significantly accelerating and improving non-catalytic steam gasification in fluidized bed gasifiers through the appropriate organization of in-core coal treatment. Based on the results obtained, the following recommendation is made—when designing multi-section and multi-vessel steam-blown gasifiers, the ratio of residence times should be set in favor of increasing the coal residence time in the steam-blown carbonization zone. Structurally, this can be achieved by increasing the volume and/or area of the steam-blown carbonization section (vessel).

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V.G. Tuponogov

Papers

The velocity of sound in fluidised beds

Investigation into the operation of an autothermal two-section subbituminous coal fluidized bed gasifier

Parameters of surface standing waves in fluidized bed apparat with different diameter

Steam Gasification in a Fluidized Bed with Various Methods of In-Core Coal Treatment

Modeling of a syngas solid-sorbent desulfurization reactor