scholarly journals Stability of pyrolysis condensates during their high-temperature treatment

Paliva ◽  
2021 ◽  
pp. 131-140
Author(s):  
Marek Staf ◽  
Michal Pohořelý ◽  
Siarhei Skoblia ◽  
Zdeněk Beňo ◽  
Vít Šrámek
Keyword(s):  
High Temperature ◽  
Vapour Phase ◽  
Temperature Treatment ◽  
Dew Point ◽  
Laboratory Simulation ◽  
High Temperature Treatment ◽  
Waste Plastics ◽  
Pyrolysis Gas ◽  
In Series ◽  
High Temperature Reactor

As part of a project dealing with the material use of waste plastics processed by pyrolysis, a method for the purification of primary pyrolysis gas at temperatures above the dew point of condensing components was proposed. In order to avoid the loss of liquid products, two procedures have been proposed to study this issue. The first procedure consists in separating the pyrolysis condensate from permanent gases and its subsequent evaporation and introduction into a high-temperature reactor where the purification takes place. The second procedure used the same equipment, but the pyrolyser was connected in series with a high temperature reactor by a heated tube. The function of the device is demonstrated on a pair of pure polymers, namely highdensity polyethylene and polypropylene. In practice, however, the device is used for testing waste plastics. The mass balance of liquid, gaseous and solid products of pyrolysis and subsequent vapour phase conduction through a high-tem-perature reactor was supplemented by data from chromatographic analysis. Experiments have shown that the separation of pyrolysis and subsequent evaporation of the condensate in an independent reactor causes the formation of an undesirable amount of fine aerosol (mist). Pyrolysis without any subsequent high-temperature step produced 85–90 % condensate. The inclusion of a separate high-temperature reactor reduced the yield of condensate to 44.5–47.5 %, at the expense of the above-mentioned mist. Its conver-sion back to liquid is difficult and makes the process inefficient for industry. In tests with the series-connected pyrolyser and the high-temperature reactor, the situation was significantly better. 68.5–73.5 % of condensate was obtained in this case. In addition to the formation of mist, the conduction of steam of condensing components through the high-temperature reactor also caused a slight change in the composition of the liquids obtained. There was a decrease in the proportion of C21–C29 hydrocarbons in products and, conversely, an increase in the concentration of C5–C15 hydrocarbons. Besides verifying a suitable approach to the high-temperature processing of pyrolysis products, the experiments showed that changing a single subparameter (in this case the separation of the two reactors) significantly altered the results of the experiments. During laboratory simulation of industrial processes, it is important not to approach simplifications, but to copy all conditions as much as possible.

An experimental study on the fracture behaviors of marble specimens subjected to high temperature treatment

2020 ◽  
Vol 225 ◽  
pp. 106862 ◽  
Author(s):  
Qingzhen Guo ◽  
Haijian Su ◽  
Jiawei Liu ◽  
Qian Yin ◽  
Hongwen Jing ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Fracture Behaviors

scholarly journals Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1695-1700 ◽  
Author(s):  
A. Murillo-Williams ◽  
G. P. Munkvold
Keyword(s):  
High Temperature ◽  
Environmental Factors ◽  
Fusarium Verticillioides ◽  
Systemic Infection ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Kernel Infection ◽  
Temperature Regimes ◽  
Maize Plants ◽  
Systemic Development

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

Properties of maraging steels after high-temperature treatment

1981 ◽  
Vol 23 (4) ◽  
pp. 265-267
Author(s):  
O. V. Abramov ◽  
A. I. Il'in ◽  
V. M. Kardonskii
Keyword(s):  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Maraging Steels

6H- AND 4H-SiC(0001) Si SURFACE RICHNESS DOSING BY HYDROGEN ETCHING: A WAY TO REDUCE THE FORMATION TEMPERATURE OF RECONSTRUCTIONS

2003 ◽  
Vol 10 (01) ◽  
pp. 55-63 ◽  
Author(s):  
M. DIANI ◽  
J. DIOURI ◽  
L. KUBLER ◽  
L. SIMON ◽  
D. AUBEL ◽  
...  
Keyword(s):  
High Temperature ◽  
Atomic Hydrogen ◽  
Room Temperature ◽  
Binary Systems ◽  
Temperature Treatment ◽  
Heating Time ◽  
High Temperature Treatment ◽  
Formation Temperature ◽  
Hydrogen Etching ◽  
Chemical Surface

In 6H- or 4H-SiC(0001) surface technology, a Si-rich 3 × 3 reconstruction is usually first prepared by heating at 800°C under Si flux, and two other most stable [Formula: see text] or [Formula: see text] reconstructions are obtained by further extensive annealing at higher temperatures ranging between 900 and 1250°C. The 3 × 3 Si excess is thus progressively depleted up to a graphitized C-rich surface. By crystallographic (LEED) and chemical surface characterizations (XPS and UPS), we show that all these reconstructions can be obtained at a unique, low formation temperature of 800°C if the Si richness is controlled before annealing. This control is achieved by exposing the 3 × 3 surface to atomic hydrogen at room temperature. This procedure allows one to etch or partially deplete the (3 × 3)-associated Si excess, and make it more comparable to the final Si coverages, required to form the less Si-rich [Formula: see text] or [Formula: see text] reconstructions. After annealing at 800°C, the latter reconstructions are no longer determined by the heating time or temperature but only by the initial Si coverage set by the H doses inducing the low temperature etching. The high temperature treatment, required to remove by sublimation a significant Si amount associated with the Si-rich 3 × 3 reconstruction, is thus avoided. Such a methodology could be applied to other binary systems in the formation of reconstructions that depends on surface richness.

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