🜍 Total sulphur and ash sulphur in solid fuels — automatic analysers — PN-G-04584

Petrochemistry PN-G-04584

Overview

SCOPE FROM THE PKN CATALOGUE CARD, QUOTED VERBATIM (our translation): "A method for the determination of the content of total sulphur and ash sulphur in solid fuels with automatic analysers is given. The principle of the method, reagents and materials used, apparatus, preparation of the test sample and preparation of the analyser, the procedure of determination, the precision of the method and the final result are given."

TWO DETERMINATIONS, NOT ONE — AND THAT IS THE MOST IMPORTANT THING IN THIS STANDARD. Total sulphur is all the sulphur contained in the fuel. Ash sulphur is the part of it that remains bound in the ash after combustion, mainly in the form of sulphates. Both determinations are carried out according to the same standard, but they measure different things and answer different questions. A report that states "sulphur" without indicating which one is meant is ambiguous.

THE DIFFERENCE BETWEEN THEM HAS ENVIRONMENTAL SIGNIFICANCE. Sulphur that is not retained in the ash escapes with the flue gases as sulphur dioxide. That is why comparing both results makes it possible to estimate what part of the fuel sulphur goes into the atmosphere and what part remains in the combustion residue. For the operator of an installation, this information translates directly into the choice of desulphurisation and into emission reporting.

WHAT THIS STANDARD REPLACED. The 2001 edition replaced two parts of an older standard: PN-G-04514-16:1990 and PN-G-04514-17:1993. Citations of both parts are still found in accreditation scopes — they are out of date, and their place has been taken by one document covering both determinations.

WHY SULPHUR IS SOMETIMES DIFFICULT TO DETERMINE. It occurs in coal in several forms — as pyritic sulphur bound in minerals, as organic sulphur built into the coal substance and as sulphate sulphur. Each of them behaves differently on heating, which is why the combustion conditions in the analyser must ensure that all the sulphur is converted into a determinable form. We do not give these conditions — they are in the text of the standard.

STATUS OF THE DOCUMENT. The PKN catalogue card has no "Withdrawn" heading and no "Withdrawal date" line; the standard remains in the collection of Polish Standards and citing it is correct.

THE AUTOMATIC ROUTE IS NOT THE ONLY ONE — AND THIS CAN BE SEEN IN PRACTICE. The Department of Solid Fuels Quality Assessment of the Central Mining Institute (Główny Instytut Górnictwa) lists two ways of determining total sulphur side by side: with TruSpec CHNS and CHNS628 analysers and by the ESCHKA METHOD using muffle furnaces. This standard describes only the automatic route; the Eschka method has its own reference document. The choice of route must be recorded in the report, because citing this standard specifically means determination with an analyser, not "determination of sulphur" in general. The CHNS analyser also covers carbon, hydrogen and nitrogen — the determinations of PN-G-04571 — so one instrument serves two standards. WHAT WE DO NOT GIVE. We did not have the text of the standard. WE DO NOT GIVE: the test portion and particle size of the sample, the combustion and incineration temperatures, the type of detection, the list of reagents, the method of preparing the analyser or precision values. The card lists these clauses as the content of the standard but does not quote them.

SCALE OF CITATIONS — MEASUREMENT IN THE ACCREDITATION SCOPE DATABASE (read on 23-09-2026, matching by the BEGINNING of the notation "PN-G-04584", i.e. the way the "Laboratories" tab of this entry searches): 75 entries at 52 laboratories.

Method principle

The determination of total sulphur consists in burning a weighed sample of fuel under conditions that ensure conversion of all the sulphur — pyritic, organic and sulphate — into a determinable form, and then determining it with the detector of the analyser. Ash sulphur is determined analogously in the ash obtained by incinerating the sample, so it covers only the part of the sulphur that remained bound after combustion. We do not give the conditions of either determination — they are in the text of the standard.

Applications

• Control of the sulphur content of coal supplied to power generation
• Assessment of compliance with quality requirements for solid fuels in trade
• Estimating sulphur dioxide emissions from combustion installations
• Selection and supervision of flue gas desulphurisation installations
• Testing of secondary fuels and coke, if the documentation cites this standard

Key parameters

Standard

Standard number

PN-G-04584:2001 (wersja polska)

Title (PL)

Paliwa stałe — Oznaczanie zawartości siarki całkowitej i popiołowej automatycznymi analizatorami

Title (EN)

Solid fuels — Determination of total and ash sulfur content by automatic analysers

Step-by-step procedure

1. Establishing which determination was ordered

   Total sulphur and ash sulphur are two different quantities. An order for "sulphur" without further specification requires clarification with the client before testing.

2. Checking that the citation is current

   If the documentation cites PN-G-04514-16 or PN-G-04514-17, the citation is out of date — both parts have been replaced by this standard.

3. Sample preparation

   Crushing and dividing in accordance with the standards on the preparation of fuel samples. WE DO NOT GIVE THE PARTICLE SIZE OR TEST PORTION.

4. Incineration of the sample (for ash sulphur)

   Obtaining the ash in which the sulphur remaining after combustion is determined. WE DO NOT GIVE THE INCINERATION CONDITIONS.

5. Determination in the analyser

   Combustion and measurement. WE DO NOT GIVE THE COMBUSTION CONDITIONS OR THE DETECTION METHOD.

6. Quality control

   Reference material in the series; assess discrepancies against the clause of the standard on precision.

7. Recording the result

   State whether total sulphur or ash sulphur is given, and the reference state. Comparing both quantities makes it possible to assess how much sulphur escapes with the flue gases.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Combustion products contain sulphur dioxide — a gas irritating to the respiratory tract; work with an efficient extraction system
• The muffle furnace and the analyser operate at high temperature — risk of burns when removing crucibles
• Oxygen under pressure violently intensifies burning — fittings free of grease and oils
• Coal dust is combustible and explosive in suspension — avoid dust formation when weighing
• Fine-grained ash is easily raised as dust and is sometimes alkaline — eye and respiratory protection

Frequently asked questions