Effect Of Pyrolysis Pressure Research Articles

Effect of pyrolysis pressure on activity of Fe–N–C catalysts for oxygen reduction

In the synthesis of Fe–N–C catalysts by high-pressure pyrolysis, higher precursor loading increases gas-phase pressure and enhances nitrogen retention, active site density and ORR activity.

Experimental study on the effect of pyrolysis pressure, peak temperature, and particle size on the potential stability of vine shoots-derived biochar

This study examines the effect of three key operating factors (peak temperature, particle size and pressure) on the potential stability of the biochar produced by slow pyrolysis of vine shoots. The following response variables were considered as key indicators of the potential stability of biochar in soils: the fixed-carbon yield, the fraction of aromatic carbon, and the molar H:C and O:C ratios. Slow pyrolysis tests were conducted in a laboratory-scale fixed-bed unit and planned according to a 2-level factorial design. The behavior of the product gas yield and composition at the outlet of the secondary cracking reactor (a fixed-bed of activated alumina particles at 700°C) was also evaluated as a function of the three factors. The results from the statistical tests revealed that the particle size is the most significant factor in determining the potential stability of biochars. Using larger particles of biomass and, in a lesser extent, operating at higher peak temperatures leads to the production of more stable materials. Unexpectedly, the absolute pressure only plays a significantly positive role in decreasing the tar content in the producer gas at the outlet of a secondary cracking reactor.

The Physical Properties and Gasification Activities of Pressurized Rapid Pyrolysis Chars from Coal and Petroleum Coke

In the pressurized rapid pyrolysis process, the two kinds of carbonaceous materials (coal and petroleum coke) presented some different pyrolysis behaviors, resulting in some different effects of pyrolysis conditions (thermal history and pyrolysis pressure) on their physical properties (carbon crystalline structure and surface area). The gasification activity of their resultant chars prepared at the ambient pressure was higher than that of their corresponding ones prepared at the pressurized pyrolysis. However, at the pressurized pyrolysis, the effects of pyrolysis pressure on the gasification activity of their resultant chars were obviously discriminated, which was likely to be quite pertinent with that whether the tars were produced or not during the pyrolysis.

3-92-2 バイオマスチャーのCO_2ガス化速度に及ぼす熱分解圧力およびCO_2/O_2濃度の影響(Session3 バイオマス等,ポスター発表)

3-92-2 バイオマスチャーのCO_2ガス化速度に及ぼす熱分解圧力およびCO_2/O_2濃度の影響(Session3 バイオマス等,ポスター発表)

Direct synthesis of highly crystalline transparent conducting oxide nanoparticles by low pressure spray pyrolysis

In this article, we firstly reported a general preparation method for the production of highly crystallized and single crystalline transparent conducting oxide (TCO) nanoparticles: tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), aluminum-doped zinc oxide (AZO), and gallium-doped zinc oxide (GZO). Low-pressure spray pyrolysis was applied by means of a modified-atomizer and preheated carrier gas. The effects of pyrolysis pressure, temperature and carrier gas temperature on the size and morphology of the synthesized TCO nanoparticles were systematically investigated. The synthesized TCO nanoparticles were 17 nm large with crystallite size of 8–11 nm. The resistivities of the formed pellets were measured and compared. These results showed that this method successfully produces various TCO nanoparticles using neither dispersing agents nor post-heating treatments, which allows rapid, continuous, single-step preparation.

06/00846 Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity: Cetin, E. et al. Fuel, 2005, 84, (10), 1328–1334.

06/00846 Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity: Cetin, E. et al. Fuel, 2005, 84, (10), 1328–1334.

BIOMASS GASIFICATION KINETICS: INFLUENCES OF PRESSURE AND CHAR STRUCTURE

ABSTRACT In this study, the gasification kinetics of chars from different biomass species have been investigated within the temperature range 800–950°C, CO2 concentrations of 10 to 100% v/v, and pressures between 1 and 20 bar using thermogravimetric analysis (TGA). The quartz wool matrix (QWM) method was used to simulate circulating fluidized-bed (CFB) conditions. The reactivity results obtained by the QWM method were compared with those extracted using TGA data. Kinetic data from TGA analyses was found to be compatible for predicting CFB gasification reactivity. Effects of pyrolysis pressure on the chemical structure of char and char conversion reactivities were also investigated. Pressure has been found to have no effect on reactivity during char conversion while having a dramatic effect on chemical and physical structure during the pyrolysis process. The Langmuir–Hinshelwood rate equation represents the pressurized radiata pine char gasification kinetics well. The Langmuir–Hinshelwood expression for studied conditions can be described as Kinetic data found in this study are in good agreement with the literature.

Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity

The knowledge of biomass char gasification kinetics has considerable importance in the design of advanced biomass gasifiers, some of which operate at high pressure. The char gasification kinetics themselves are influenced by char structure. In this study, the effects of pyrolysis pressure and heating rate on the char structure were investigated using scanning electron microscopy (SEM) analysis, digital cinematography, and surface area analysis. Char samples were prepared at pressures between 1 and 20 bar, temperatures ranging from 800 to 1000 °C, and heating rates between 20 and 500 °C/s. Our results indicate that pyrolysis conditions have a notable impact on the biomass char morphology. Pyrolysis pressure, in particular, was found to influence the size and the shape of char particles while high heating rates led to plastic deformation of particles (i.e. melting) resulting in smooth surfaces and large cavities. The global gasification reactivities of char samples were also determined using thermogravimetric analysis (TGA) technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure.

Influence of pyrolysis conditions on the structure and gasification reactivity of biomass chars

The physical and chemical structure as well as gasification reactivities of chars generated from several biomass species (i.e. pinus radiata, eucalyptus maculata and sugar cane bagasse) were studied to gain insight into the role of heating rate and pressure on the gasification characteristics of biomass chars. Char samples were generated in a suite of reactors including a wire mesh reactor, a tubular reactor, and a drop tube furnace. Scanning electron microscopy analysis, X-ray diffractometry, digital cinematography and surface area analysis were employed to determine the impact of operating conditions on the char structure. The global gasification reactivities of char samples were also determined for a range of pressures between 1 and 20 bar using pressurised thermogravimetric analysis technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. It was found that under high heating rates the char particles underwent plastic deformation (i.e. melted) developing a structure different to that of the virgin biomass. Pressure was also found to influence the physical and chemical structures of char particles. The difference in the gasification reactivities of biomass chars at pressure was found to correlate well with the effect of pyrolysis pressure on the graphitisation process in the biomass char structure.

On the Effects of High Pressure and Heating Rate during Coal Pyrolysis on Char Gasification Reactivity

Effects of pyrolysis pressure on char reactivity remain a poorly understood aspect of the coal gasification process. In an attempt to address this problem, effects of pyrolysis pressure on char structure and reactivity are being investigated. In this paper, chemical reactivities to O2, CO2, and H2O of chars made from three Australian black coals were measured in a pressurized thermogravimetric analyzer, under conditions where chemical processes alone controlled reaction rates. These chars were prepared at a range of pyrolysis pressures, using pressurized flow reactors and an atmospheric pressure tube furnace, to ascertain any effects of devolatilization pressure and heating rate on the chemical reactivity of the resultant coal chars. It was found that while the apparent (as measured) reaction rate can be affected by pyrolysis pressure, the rate normalized to the char surface area (intrinsic rate) is much less affected, because of large effects of pyrolysis pressure on char micropore surface area. This fin...