Influence of the Gas and Particle Residence Time on Fast Pyrolysis of Lignite

2006 ◽  
Vol 129 (2) ◽  
pp. 152-158 ◽  
Author(s):  
Lijie Cui ◽  
Wenli Song ◽  
Jiayuan Zhang ◽  
Jianzhong Yao ◽  
Weigang Lin
Keyword(s):  
Residence Time ◽  
Circulating Fluidized Bed ◽  
Product Distribution ◽  
Liquid Fuels ◽  
High Yield ◽  
Flash Pyrolysis ◽  
Particle Residence Time ◽  
Coal Particles ◽  
Liquid Products ◽  
Secondary Reactions

Coal resource is abundant in China, while the reserves of natural gas and petroleum are limited. Due to the rapid increase in the number of automobiles, a competitive way to produce liquid fuels from coal is urgently needed in China. A so-called “coal topping process” is under development at the Institute of Process Engineering, Chinese Academy of Sciences, from which liquid products can be obtained by flash pyrolysis in an integrated circulating fluidized bed system. In order to achieve a high yield of liquid products from high volatile coal, controlling the residence time of coal particles and produced gas may be of importance for minimizing the degree of the secondary reactions; i.e., polymerization and cracking of the liquid products. Experiments of the flash pyrolysis of coal have been conducted in an entrained bed reactor, which is especially designed to study the influence of the coal particle residence time on the product distribution. The results show that the gaseous, liquid, and solid product distribution, the gas compositions as well as the liquid compositions depend strongly on the gas and particle residence time.

Product Distribution From Flash Pyrolysis of Coal in a Fast Fluidized Bed

2003 ◽  
Author(s):  
Lijie Cui ◽  
Jianzhong Yao ◽  
Weigang Lin ◽  
Zheng Zhang
Keyword(s):  
Particle Size ◽  
Pyrolysis Temperature ◽  
Pyrolysis Product ◽  
Product Distribution ◽  
Gaseous Product ◽  
Flash Pyrolysis ◽  
Product Distributions ◽  
Liquid Products ◽  
Liquid Yield ◽  
Increasing Temperature

The flash pyrolysis of Huolinhe coal was carried out in a fast-entrained bed reactor. The investigation focuses on the effects of pyrolysis temperature and particle size on pyrolysis product distributions and gas and liquid compositions. Increasing temperature results in an increase of the gaseous product. There is an optimum temperature on the maximum liquid yield, which is around 650°C. An increase in particle size leads to a decrease of liquid products. Some amount of phenol group was found in the liquid products, which may produce the chemicals with high value. The results provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.

Particle Residence Time and Particle Mixing in a Scaled Internal Circulating Fluidized Bed

2002 ◽  
Vol 41 (11) ◽  
pp. 2637-2645 ◽  
Author(s):  
Ralf Kehlenbeck ◽  
John G. Yates ◽  
Renzo Di Felice ◽  
Hermann Hofbauer ◽  
Reinhard Rauch
Keyword(s):  
Fluidized Bed ◽  
Residence Time ◽  
Circulating Fluidized Bed ◽  
Particle Residence Time ◽  
Particle Mixing

scholarly journals Hydrogenolysis of lignin in ZnCl2 and KCl as an inorganic molten salt medium

Holzforschung ◽  
2015 ◽  
Vol 69 (5) ◽  
pp. 523-529
Author(s):  
Jörn Appelt ◽  
Anne Gohrbandt ◽  
Jana Peters ◽  
Martina Bremer ◽  
Steffen Fischer
Keyword(s):  
Molten Salt ◽  
Residence Time ◽  
Reaction Temperature ◽  
Eutectic Mixture ◽  
Gas Chromatography Mass Spectrometry ◽  
Lignin Concentration ◽  
Gaseous Products ◽  
Organosolv Lignin ◽  
Liquid Products ◽  
Secondary Reactions

Abstract Lignin can be converted into monomeric products with the aid of molten salt media. Molten zinc chloride (ZnCl2)/potassium chloride (KCl) mixtures are suitable for this purpose. The application of an eutectic mixture with low melting points leads to similar main products as are obtained by pyrolysis. The hydrogenolysis of an organosolv lignin in molten salts of ZnCl2/KCl was investigated as a function of reaction temperature, residence time, and lignin concentration, and the composition of liquid products and monophenols was analyzed by gas chromatography-mass spectrometry (GC-MS). The yields can be optimized by the proper selection of the reaction temperature. A longer residence time and higher lignin concentrations lead to increased formation of solid residues and gaseous products. The liquid products mainly consist of substituted phenols derived from lignins. Polymeric products are the result of condensation reactions (i.e., the formation of new C-C linkages in the course of secondary reactions).

scholarly journals Plastic waste to fuels by hydrocracking at mild conditions

2021 ◽  
Vol 7 (17) ◽  
pp. eabf8283
Author(s):  
Sibao Liu ◽  
Pavel A. Kots ◽  
Brandon C. Vance ◽  
Andrew Danielson ◽  
Dionisios G. Vlachos
Keyword(s):  
Direct Method ◽  
Acid Sites ◽  
Liquid Fuels ◽  
High Yield ◽  
Tandem Catalysis ◽  
Hy Zeolite ◽  
Environmental Threat ◽  
Single Use ◽  
Initial Activation ◽  
A Direct Method

Single-use plastics impose an enormous environmental threat, but their recycling, especially of polyolefins, has been proven challenging. We report a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons, with high yield up to 85% over Pt/WO3/ZrO2 and HY zeolite in hydrogen at temperatures as low as 225°C. The process proceeds via tandem catalysis with initial activation of the polymer primarily over Pt, with subsequent cracking over the acid sites of WO3/ZrO2 and HY zeolite, isomerization over WO3/ZrO2 sites, and hydrogenation of olefin intermediates over Pt. The process can be tuned to convert different common plastic wastes, including low- and high-density polyethylene, polypropylene, polystyrene, everyday polyethylene bottles and bags, and composite plastics to desirable fuels and light lubricants.

Product distribution for flash pyrolysis of cellulose in a coil pyrolyzer

1987 ◽  
Vol 10 (3) ◽  
pp. 225-249 ◽  
Author(s):  
T. Funazukuri ◽  
R.R. Hudgins ◽  
P.L. Silveston
Keyword(s):  
Product Distribution ◽  
Flash Pyrolysis

Effect of Particle Residence Time on Particle Dispersion in a Plane Mixing Layer

1993 ◽  
Vol 115 (4) ◽  
pp. 751-759 ◽  
Author(s):  
Tsuneaki Ishima ◽  
Koichi Hishida ◽  
Masanobu Maeda
Keyword(s):  
Gas Phase ◽  
Residence Time ◽  
Time Scale ◽  
Characteristic Time ◽  
Mixing Layer ◽  
Particle Dispersion ◽  
Laser Doppler Velocimeter ◽  
Characteristic Time Scale ◽  
Two Phase ◽  
Particle Residence Time

A particle dispersion has been experimentally investigated in a two-dimensional mixing layer with a large relative velocity between particle and gas-phase in order to clarify the effect of particle residence time on particle dispersion. Spherical glass particles 42, 72, and 135 μm in diameter were loaded directly into the origin of the shear layer. Particle number density and the velocities of both particle and gas phase were measured by a laser Doppler velocimeter with modified signal processing for two-phase flow. The results confirmed that the characteristic time scale of the coherent eddy apparently became equivalent to a shorter characteristic time scale due to a less residence time. The particle dispersion coefficients were well correlated to the extended Stokes number defined as the ratio of the particle relaxation time to the substantial eddy characteristic time scale which was evaluated by taking account of the particle residence time.

Sign in / Sign up

Export Citation Format

Share Document