Coal — Determination of carboxyreactivity

This document specifies the method for determining the reactivity of coal with carbon dioxide (carboxyreactivity). It can be applied to determine the reactivity of coke for the purpose of gasification and combustion.

Charbon — Détermination de la carboxyréactivité

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ISO/TS 4676:2022 - Coal — Determination of carboxyreactivity Released:15. 07. 2022
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Coal — Determination of
Charbon — Détermination de la carboxyréactivité
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ISO/TS 4676:2022(E)
© ISO 2022

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ISO/TS 4676:2022(E)
© ISO 2022
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ISO/TS 4676:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Preparation of test sample . 3
8 Procedure .4
9 Expression of result . 4
10 Precision . 5
10.1 Repeatability limit . 5
10.2 Reproducibility limit . 5
11 Test report . 5
Annex A (normative) Correction of the flow rate of CO . 6
Annex B (informative) Example for report of carboxyreactivity determination .7
Bibliography . 8
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ISO/TS 4676:2022(E)
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This document was prepared by Technical Committee ISO/TC 27, Coal and Coke, Subcommittee SC 5,
Methods of analysis.
  © ISO 2022 – All rights reserved

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ISO/TS 4676:2022(E)
Coal gasification is an important technology for clean coal conversion, which involves many factors.
The chemical reactivity of coal is one of the essential parameters for the gasification industry and its
relevant coal trade.
The chemical reactivity of coal with CO (carboxyreactivity of coal) is a measurement of the coal’s ability
to reduce CO to CO, which is an important parameter of evaluating the coal quality for gasification and
combustion industry. The level of carboxyreactivity of coal is directly related to other characteristics
of the coal in the gasification or combustion furnace like the reactive extent, the reaction speed and
efficiency, the consumption of coal and oxygen, the effective compositions of the coal gas, so it is not
only used for evaluating the applicability of coal for gasification, combustion, indirect liquefaction, etc.,
but also for guiding users to select coal used for above technologies.
This document integrates and modifies GB/T 220 to specify a method for determining the reactivity
of coal with carbon dioxide (carboxyreactivity). It can also be applied to determine the reactivity of
coke for the purpose of gasification and combustion.
© ISO 2022 – All rights reserved

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Coal — Determination of carboxyreactivity
1 Scope
This document specifies the method for determining the reactivity of coal with carbon dioxide
(carboxyreactivity). It can be applied to determine the reactivity of coke for the purpose of gasification
and combustion.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 18283, Coal and coke — Manual sampling
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-2 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
A coal sample with the size fraction of 3 mm to 6 mm is carbonized in a dry distillation furnace to
remove the volatile matter (this is not necessary for coke samples). Sieve and collect a portion of the
carbonized products (coke residue) with the designated size. Put them into the reaction tube and heat
to the specified rates. When the required temperature is achieved, pass CO gas through the reaction
tube at a uniform flow rate. Determine the volume fraction of residual CO in the gases by a gas analyser
at the specified time of passing CO gas. Calculate the ratio α (%) of CO gas being reduced to CO and
2 2
take it as the index of the carboxyreactivity at the specified temperature.
5 Reagents
Unless otherwise specified, all reagents shall be of analytical reagent grade, and only distilled water, or
water of equivalent purity, shall be used.
5.1 Anhydrous calcium chloride.
5.2 Sulfuric acid, relative density, ρ = 1,84.
5.3 Potassium hydroxide or sodium hydroxide solution, 500 g/l.
Dissolve 50 g of potassium hydroxide or sodium hydroxide in 100 ml of distilled water.
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