Natural Gas Odorization

Non

Enrichment of Limestone Used in the Desulphurisation of Fluidised-Bed-Boiler Flue Gases

In this work, we analysed the impact of adding several previously untested Sorbacal calcium-based substances to the raw limestone that is currently used for dry desulphurisation of brown-coal fluidised-bed boilers. Our focus was to examine whether these additives could potentially improve the limestone SO2 adsorption capacity. The main criterion was the time period for which each enriched limestone was able to keep its desulphurisation ability, i.e., time for which the SO2 concentration in the heated model flue gas was kept below 200 mg/m3 (current legal limit for the technology in our scope). The analysis showed that the limestone desulphurisation ability increased when 20% of Sorbacal SP was added to the calcined limestone. The overall desulphurisation capacity of this enriched mass was even higher than what would be proportional to the isolated capacity of the additive itself. On the other hand, the enrichment of raw limestone with Sorbacal H 90 proved to be unpromising for the technology of brown-coal fluidised-bed boilers as the fine particles of the additive were carried away, and fluidised bed was inhomogeneous with ducts forming in it

EFFECT OF HIGH-TEMPERATURE INERT GAS ATMOSPHERE ON THE THERMAL STABILITY OF ADVANCED REFRACTORY MATERIALS

The effect of long-term exposure to a high-temperature gas atmosphere on the stability of ceramic materials has been investigated. Material samples based on ZrO₂ (Zr85, Zr95), Al₂O₃ (Al100), Al₂O₃-SiO₂ (Al63, Al70, Al76, Al96) and SiC (Si100) were exposed to an atmosphere of dry helium and nitrogen (the dew point of water was approximately −70 °C) at a temperature of 900 °C for 1000 hours. Bending-strength tests at 20 °C and Hot modulus of rupture (HMOR) tests at 900 °C were performed on the exposed and unexposed samples. In addition, the chemical composition of the materials tested and their criteria of relative density, i.e., bulk density, apparent porosity and water absorption, were determined together with their changes after the material exposure. The most pronounced change in the bending strength at 20 °C was observed after the Zr95 exposure to nitrogen, with an increase of up to approximately 25 % from the initial state. At 900 °C, the bending strength increased by about 15-20 % for Zr95 and Zr85 after exposure to helium and nitrogen. On the other hand, when Al63 was exposed to helium and nitrogen at 900 °C, its bending strength decreased. There were no substantial changes in the bending strength of the other materials tested after the exposure. Also, the exposure did not have a significant effect on the change in the criteria of relative density or chemical composition of any of the tested materials. Keywords: high-temperature ceramics; mullite ceramics; helium; nitroge