Search results

Filters

  • Journals
  • Date

Search results

Number of results: 3
items per page: 25 50 75
Sort by:

Abstract

The research was aimed at examining the impact of the petrographic composition of coal from the Janina mine on the gasification process and petrographic composition of the resulting char. The coal was subjected to fluidized bed gasification at a temperature below 1000°C in oxygen and CO2 atmosphere. The rank of coal is borderline subbituminous to bituminous coal. The petrographic composition is as follows: macerals from the vitrinite (61.0% vol.); liptinite (4.8% vol.) and inertinite groups (29.0% vol.). The petrofactor in coal from the Janina deposit is 6.9. The high content of macerals of the inertinite group, which can be considered inert during the gasification, naturally affects the process. The content of non-reactive macerals is around 27% vol. The petrographic analysis of char was carried out based on the classification of International Committee for Coal and Organic Petrology. Both inertoid (34.7% vol.) and crassinetwork (25.1% vol.) have a dominant share in chars resulting from the above-mentioned process. In addition, the examined char contained 3.1% vol. of mineroids and 4.3% vol. of fusinoids and solids. The calculated aromaticity factor increases from 0.75 in coal to 0.98 in char. The carbon conversion is 30.3%. Approximately 40% vol. of the low porosity components in the residues after the gasification process indicate a low degree of carbon conversion. The ash content in coal amounted to 13.8% and increased to 24.10% in char. Based on the petrographic composition of the starting coal and the degree of conversion of macerals in the char, it can be stated that the coal from the Janina deposit is moderately suitable for the gasification process.
Go to article

Abstract

Activation of tyre pyrolysis char (TPC) can significantly increase its market value. To date, it has been frequently carried out in different reactors. In this work, thermogravimetric analysis was used instead. The performance of activated pyrolysis chars was tested by adsorption of acetone vapour and comparison of the equilibrium adsorption capacities for all samples. The highest equilibrium adsorption capacity was observed for the carbon burn-off of #24; 60%. In addition, the equilibrium adsorption capacity of activated TPC decreases by about 10% after eleven adsorption/desorption cycles. Moreover, activation changed the porous structure of pyrolysis chars from mesoporous to micro-mesoporous.
Go to article

Abstract

cAMP is a second messenger which plays a regulatory role in a wide variety of biological processes in organisms ranging from prokaryotes to higher eukaryotes, but knowledge of its role in macroalgae and vascular plants is limited. We modified cAMP levels in the macroalga Chara vulgaris thallus and studied the effects on thallus growth and gametangia development: db-cAMP (permeable analog of cAMP), adenylate cyclase (AC) activator, forskolin and theophylline (cAMP phosphodiesterase (PDE) inhibitor) were used to elevate cAMP levels, and the AC inhibitors 2'-dAdo and 2'-d3'-AMP were used to decrease them. The results suggest that in Chara vulgaris the cAMP pathway may regulate both vegetative thallus growth and gametangia development, and that these effects may depend on this second-messenger level. Elevated cAMP stimulated thallus growth and delayed gametangia development; decreased cAMP inhibited thallus growth and accelerated maturation of both antheridia and oogonia. These results suggest that the cAMP pathway participates in regulation of developmental processes in Chara vulgaris and that thallus growth and gametangia development require different cAMP levels in cells.
Go to article

This page uses 'cookies'. Learn more