DIN 54388
Solid recovered fuels - Determination of the water-soluble content of chloride, sodium and potassium using the liquid obtained by the press method
Feste Sekundärbrennstoffe - Bestimmung des wasserlöslichen Gehaltes an Chlorid, Natrium und Kalium über die Pressflüssigkeit nach der Pressmethode
Overview
This document applies to solid substitute fuels, recovered fuels, biofuels and lightweight packaging, light shredder fractions, high-calorific fractions, biologically treated waste or landfills, paper, cardboard, plastics and textiles, and generally to solid materials of low bulk density. The prerequisite is that the materials can be pressed or compacted. The pressing method is intended to enable the determination of the water-soluble content of chloride, sodium and potassium in solid waste-derived materials directly via the pressing liquid according to the pressing method. The laboratory sample is pressed in a press cylinder. In this process the resulting press liquid is subjected to liquid-solid phase separation, followed by dilution of the press liquid with water. The analysis liquid and the reserve sample for the determination of water-soluble chloride, sodium and potassium are taken from this liquid by means of a suitable measuring method (for example IC, ICP OES, ICP MS). If the total water content is less than 25 % by mass, conditioning is necessary to ensure that the press liquid is secured. The main problem in the thermal utilization of waste-derived recovered fuels or high-calorific fractions is the chlorine content and the resulting corrosion processes, especially on the walls of the furnace and the afterburner chamber and on the superheater heating surfaces. Taking into account the many factors influencing the corrosion risk of a fuel, the common practice of singularly specifying a chlorine limit value as a sum parameter is insufficient. A differentiated specification according to the bonding form and thus separate analysis of the organic as well as the inorganically bonded chlorine content is thus required. Among others, there are currently the following methods for quantifying the content of inorganic chlorine load, DIN EN 15410 for determining the content of main elements in the field of recovered fuels, DIN EN 12457-4 for "waste" for elution and DIN EN ISO 16995 for "biogenic solid fuels" for extraction. The methods according to DIN 12457 and DIN EN ISO 16995 are based on the leaching of the soluble chlorine load with water as a suitable differentiation criterion. Accordingly, the water-soluble chlorine load in these methods corresponds in the broadest sense to the inorganic chlorine load. Practice shows that the monetary as well as time expenditure for application of the previous methods is high. Alternatively, if the waste-derived substance to be analyzed is pressed out, then the press liquid obtained can be used directly for analysis, since it is assumed that the soluble chlorine load components are homogeneously distributed in the press liquid. Because the pressing method uses a much larger laboratory sample volume of 1 l, the sampling error is smaller compared to extraction and elution (analytical samples of 1 g and 100 g, respectively). This document is intended as a supplement to the methods according to DIN EN 15410, DIN EN 12457-4 and DIN EN ISO 16995 respectively. This document has been prepared by Working Committee NA 062-05-83 AA "Sekundärbrennstoffe" ("Recovered fuels") of DIN Standards Committee Materials Testing (NMP).
