Einbindung von Alkalimetallen bei der Druckkohlensstaubfeuerung

The pressurized pulverized coal combustion (PPCC) is a concept for coal-based combined cycles with efficiencies > 50%, in which the gases from the coal combustion are used to drive a gas turbine. A mayor problem of the PPCC is the high alkali content of the hot flue gases. The alkalis released during coal combustion can react with gaseous sulphur to alkali sulphates. These compounds cause high temperature corrosion of the Ni-base alloys of the turbine bladings. For this reason, the present specification of the turbine manufacturers for the required flue gas quality is a maximum alkali content of 0.01 mg/m3 (STP). The investigations described in this thesis were performed to determine the sorption behaviour of aluminosilicates to remove alkalis from hot flue gases at 1400°C. The sorption experiments were performed in a flow channel reactor, in which an alkalichloride laden gas was passed through a sorbent bed. The alkali concentration in the flue gas downstream of the sorbent bed was determined using High Pressure Mass Spectrometry (HPMS). With this method suitable sorbents for the gas clean up from alkalis at 1400°C could be identified. The alkali laden sorbents were characterized using XRD, SEM, EDX and chemical analysis to determine the phases formed inside of the tested materials, as well as the maximum loading capacity of the sorbents. The sorption experiments showed that the alkali concentration in the hot flue gas can be reduced to values below 100 ppbVol using sorbent beds consisting of aluminosilicates. The mechanism and the kinetic of the alkalisorption were additionally investigated using impedance spectroscopy and thermogravimetry. Finally, thermodynamic calculations were performed to scale up the results of the laboratory experiments to PPCC conditions.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2007

Author dc:creator

• Escobar Muñoz, Isabel Cristina

Contributors dc:contributor

• Schneider, Jochen M.

• info:eu-repo/classification/ddc/620
• Alkalieinbindung
• Sorbentien
• Heissgasreinigung
• DKSF
• Hochtemperaturkorrosion
• Ingenieurwissenschaften
• Alkali Sorption
• Hot gas cleaning
• PPCC
• Sorbent
• Hot Corrosion

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123988%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:62417