Understanding and Improving Thermochemical Processes

Analysis: Fossil Fuels

Many of CheMin’s senior staff completed geo-scientific training (geology, mineralogy, economic geology). Combined with our competence in the fields of corrosion and soiling in power plants, CheMin’s scope of action regarding fossil fuels (peat, brown coal, black coal) comprises all process steps, from the coal deposit to the chemical side effects in boilers and flue gas cleaning, as well as the properties of residues such as slag, ash, dusts.

Against the background of ever more complex sources and routes of fossil fuels, and the growing tendency towards co-firing and permanently increasing demands on environmental standards (NOx), fossil-fired power plants are exposed to such high levels of soiling and corrosion that have been unknown so far. The often delicate adjustments, which had been developed over decades and made specifically for the fuels from a certain deposit and the corresponding firing conditions in the boiler, are no longer applicable or need to be revised.

Soiling and corrosion are, to a large extent, independent of the “combustible” proportion of coal, but are determined by its minor mineral constituents. In this sense, boilers are chemical reactors in which these minor constituents are opened up thermally, thus made reactive. This is why the type and proportion of minor constituents in fossil fuels are of major importance.

The chemical and mineralogical analysis of the chemical reactivity of minor constituents, with their negative effect on the boiler, can be carried out at several process steps:
  • coal deposit,
  • raw fuel,
  • processed (or mixed, if necessary) fuel and
  • flue gas passage of the boiler.

Here, the classic methods of economic geology are applied to fuels (preparation of metallographic sections, reflected-light microscopy, space-resolved chemical analysis based on SEM-EDX).

Inside the boiler CheMin uses sensors in the form of probes (CheMin Probes) which are inserted into special openings during operation in order to detect and document the relevant properties of reactive minor constituents at specific positions along the flue gas stream. Firstly, this allows to make a first analysis on the causes of any existing soiling or corrosion and, secondly, to quickly assess the effectiveness of taken measures accompanying optimisation tests (fuels, firing).

CheMin offers these services tailored to the individual case so that the customer’s interests are specifically supported and promoted. Our CheMin experience shows that any standardised procedures are not helpful.

CheMin GmbH | Am Mittleren Moos 46 A | 86167 Augsburg | Germany
Phone +49 821 748 39 0 | Fax +49 821 748 39 39
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Last updated: 29.01.2019
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