Laboratory for power plant chemistry
Walther-Pauer-Bau
Chief: Dr. rer. nat. K. Gebauer
Laboratory assistant: Romy Fischer
|
Visitors address: |
Walther-Pauer-Bau, room 112/113 |
Basic investigations on fuel analysis and ash and ablation behavior are performed according to DIN or DIN conforms. A fuel analysis includes among others a brief analysis, elementary analysis, determination of calorific and heating value and sieve analysis. The melting behavior and chemical composition of fuel ash, as well as of base samples e. g. of combustion experiments, are being examined in ash and slag analyses.
Furthermore, kinetic data for ignition and ablation behavior of fuels in the field pipe, Ignition reactor and batch-reaktor are determined.
An overview of technical devices available is given under technical equipment.
Laboratory
Laboratory
Technical equipment
• analysis mill (Retsch)
• moisture analyzer HR 73 (Mettler Toledo)
• muffle furnace
• device for elementary analysis Vario el (elementary Hanau)
• carbon / sulphur-analyzer Eltra CS 500
• calorimeter C4000 (Janke & Kunkel); calorimeter C200
• vibratory screening machine AS 200 control (Retsch)
• melting microscope Jena, melting microscope Leitz
• ion chromatograph (Dionex) with suppressor technology
• thermo balance (TGA/DSC) (Mettler Toledo)
• FTIR-gas analyzer CX-4000 (Ansyco)
Laboratory
Laboratory
Chemical, calorific and mechanical fuel characteristics
Brief analysis
Water content according to DIN 51718 with HR 73 by Mettler Toledo (drying of a defined test sample to constant mass at 105 °C)
moisture analyzer HR 73
Ash content according to DIN 51719 (Combustion of a fuel sample in the muffle furnace 2 h at 815 °C)
Volatile ingredients according to DIN 51720 (coking of the fuel sample 7 minutes at 900 °C in the muffle furnace)
muffle furnace
Percentage of solid fuel (can be determined by the weight of the original sample and the total share of fluid components, water and ash)
Elementary analysis
The organic substance of the fuel is investigated for its elementary components with the help of elementary analysis. This analysis includes the determination of weight proportions of carbon, hydrogen, nitrogen and sulphur.
The proportions of the elements carbon, hydrogen and nitrogen determined with the help of an automatic elementary analysis facility (Elementar vario EL). Thereby, samples are completely burnt oxidatively at 950 - 1.000 °C in an oxygen-enriched He-atmosphere in a furnace pipe filled with CuO.
Elementary analysis facility Vario El
Sulphur analyzer Eltra CS 500
The determination of sulphur is possible with the help of an ELTRA CS 500-carbon/sulphur-analyzer. Thereby, samples are burnt and, subsequently, the flue gas is analyzed by infra-red absorption.
The percentage of oxygen is calculated as a difference to 100 %, for there is no corresponding test rig available.
Other fuel analyses
The calorific value of fuels is determined in an adiabatic bomb calorimeter by the company Janke & Kunkel (type C4000) according to DIN 51900.
Adiabatic bomb calorimeter type C4000
The ash melting behavior is determined at a hot stage microscope according to DIN 51730. The ashed sample, in accordance with DIN 51719, is grouted to a cylindric test piece which is subsequently heated in a furnace with oxidating atmosphere. Thereby, the different shapes of the ash test piece are observed and determined at their characteristic points of temperature.
Melting-microscope (Zeiss-Jena)
Initial shape
[Removed image: /die_tu_dresden/fakultaeten/fakultaet_maschinenwesen/ifvu/evt/Lehre/Ascheschmelzverhalten1.jpg Alternative text: Image caption: ]
Cylindric compact with a diameter and height of 3mm
Sintering point
[Removed image: /die_tu_dresden/fakultaeten/fakultaet_maschinenwesen/ifvu/evt/Lehre/Ascheschmelzverhalten2.jpg Alternative text: Image caption: ]
Temperature, at which agglutination of ash particles at their interfaces occurs
Softening point
[Removed image: /die_tu_dresden/fakultaeten/fakultaet_maschinenwesen/ifvu/evt/Lehre/Ascheschmelzverhalten3.jpg Alternative text: Image caption: ]
First signs of softening (changes of surface, round edges, swelling)
Hemisphere point
[Removed image: /die_tu_dresden/fakultaeten/fakultaet_maschinenwesen/ifvu/evt/Lehre/Ascheschmelzverhalten4.jpg Alternative text: Image caption: ]
Compact almost takes shape of a hemisphere and is half as high as its baseline
Flow point
[Removed image: /die_tu_dresden/fakultaeten/fakultaet_maschinenwesen/ifvu/evt/Lehre/Ascheschmelzverhalten5.jpg Alternative text: Image caption: ]
Compact dissolved to a third of its initial height
Characteristic points of temperature for determination of ash melting behavior
The grain size distribution of solid fuels is determined with the help of an automatic sieving machine in accordance with DIN 66165.
When sieving with a sieve column, several screens are laid on top of each other and tensioned to a screening machine. The sample to be analyzed is put onto the top screen and the fuel is separated into its different material sizes by the swinging horizontal movement of the screening machine.
Vibratory screening machine AS 200 "control"
The annealing loss of ash samples is determined analogous to the determination of ash percentage according to DIN 51719.
Besides the fuel parameters, the chemical composition of fuel ash according to DIN 51729 is investigated for oxides of the elements silicon, iron, aluminium, calcium, magnesium, sodium, potassium and sulphur.
An ion chromatograph ICS 1000 by Dionex is available for the general investigation of anions and cations in aqueous solutions.
Ion chromatograph ICS1000
Separation column for anions: AS9-HC, AG9-HC
Separation column for cations: CS12A CG12A
The thermal behavior of fuels and other solid materials at different thermal and atmospheric conditions can be examined with the thermo balance TGA/DSC 1. Reaction kinetics can be derived from the data gathered.
Thermo balance TGA/DSC 1
The concentration of single gases (which e. g. occur during combustion, pyrolysis etc.) in gaseous mixtures can be determined with the help of a FT-IR gas. The analysis is based on the measure of IR-spectra.
FT-IR gas analyzer
| Kinetic fuel properties: | Drop tube reactor Ignition reactor Batch-reactor |