Effect of the Moisture Content in Coal on the Pyrolysis Behavior in an Indirectly Heated Fixed-Bed Reactor with Internals

Abstract

The fixed-bed reactor with internals has been proposed to enhance the pyrolysis performance for coal. In this study, the pyrolysis behavior of different coal moisture contents and the reaction mechanism were investigated in an indirectly heated fixed-bed reactor with internals. The results showed that, at a furnace temperature of 900 °C, the increased coal moisture content went from 0.41 to 11.68 wt % and significantly modified the temperature fields, thereby prolonging the pyrolysis time to reach 500 °C and then enhancing the condensation and trapping of the coal at the bed center. Therefore, the tar yield and light tar content were raised from 9.21 and 63.7 wt % to 10.74 and 64.5 wt %, respectively. However, when the coal moisture content exceeded 16.77 wt %, the tar yield and light tar content decreased to 8.55 and 62.0 wt %, respectively. In addition, the higher heating value (HHV) of char with internals was dramatically higher than that without internals, and the char HHV in the reactor with internals rose primarily and then decreased with the increase in the coal moisture; meanwhile, its fixed carbon content of char showed an increase, followed by a decline. In contrast, the pyrolysis products varied slightly in the reactor without internals.

Effects of water on pyridine pyrolysis: A reactive force field molecular dynamics study

“…When a is 25, few C 5 þ compounds are formed during pyridine pyrolysis. This phenomenon is in agreement with previous experimental studies [7,8]. Results show that water molecules greatly inhibit polycondensation reactions and modify pathways to char, tar and gas, which is of great significance to control nitrogen migration during coal pyrolysis.…”

“…According to previous studies [8,9], pyridine molecules undergo ring opening reactions firstly during pyrolysis. Fig.…”

“…They proposed that H 2 O reduced the char generation, stabilized the char structure and increased the char reaction rate. Hu and co-workers investigated the effects of H 2 O on the pyrolysis of coal [8]. Results showed that the yield of tar and light tar decreased with water content increasing during the coal pyrolysis.…”

Slow Pyrolysis Performance and Energy Balance of Corn Stover in Continuous Pyrolysis-Based Poly-Generation Systems

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Theoretical Investigation of the Formation Mechanism of NH3 and HCN during Pyrrole Pyrolysis: The Effect of H2O

“…Hu et al [22] investigated the pyrolysis behavior and reaction mechanisms of coal samples containing different moisture contents. They found that the moisture content had a significant influence on the tar yield and light tar content, and H 2 O could upgrade the low-rank coal during pyrolysis [23].…”