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Aim

The working group on Gasification Chars was proposed at the Victoria meeting in 2007, and established at the Oviedo meeting in 2008. The reason for the establishment was based on a question: can gasification chars be classified in the same manner as combustion chars? The aim is to determine if the ICCP proposed classification scheme for combustion chars and the classification scheme for fly ash are applicable to gasification chars. Links to the Combustion and Identification and Petrographic Classification of components in fly ashes Working Groups can be found on the ICCP webpage under the Working Groups tab.

Overview coal gasification

Overview coal gasification

Coal gasification is a process that converts carbonaceous materials into carbon monoxide and hydrogen. These gases can be further processed into a variety of chemicals and liquid fuels, or used as an energy source. There are many different gasification technologies, although they can all essentially be grouped into 3 categories: fixed / moving bed gasification, fluidized bed gasification, and entrained bed gasification. Each gasification technology has a different particle feed size, agent composition, agent and carbon feed rate and direction, which all influence raw syngas compositions. An understanding of the gasification chars can determine process efficiency, carbon conversion rates, fuel consumption, temperatures attained in the gasifier, and so on. Gasification performance is dependent on coal type and gasifier configuration. Further information can be found in: Wagner, Chapter 5, Coal Gasification, in Applied Coal Petrology edited by Suarez-Ruiz and Crelling, 2008.

Activities

A trail image based exercise was conducted in 2011 / 2012 using images obtained from entrained flow gasification samples. Only 4 people attempted the exercise, 3 of which participated for learning purposes. This raised the issue that not many people are actively working in the field of gasification petrography; but the ICCP requested the working group to continue, and many more participants joined, mostly to learn more about the material. Refer to presentation made in Poland 2013 for images and details.

In 2015 a second image based exercise has been developed, and will be released to participants shortly. The exercise was presented at the Potsdam meeting in 2015. The aim of the working group exercise is for members to consider a variety of petrographic images of gasification chars from different gasifiers, working towards a gasification char classification scheme. Images are from fixed / moving bed, fluidised bed and entrained flow gasifiers. Each gasifier is fed with different coal, with varying rank, type, grade, and particle size (slurry or larger). Each gasifier has different gasifying agents, pressures and products.

New participants are always welcome.

Introduction

The Micro-FTIR WG was established in 2012 in Beijing with the objective to apply Micro-FTIR measurements on coal macerals. The aim is to analyze various macerals in coals of different ranks and determine coalification parameters.

Comparative results from several labs will provide data towards a standardization of the process.

Current activities

During the Bandung Meeting 2006 the convenor presented the activities of 2005-2006 and gave new guidelines of the exercise which will be repeated next year because in 2005-2006 only one participant responded. In 2007 the convenor will provide more pictures from different samples in order to study the four parameters that the convenor proposed in 2005-2006.

Minutes

Minutes of the 55th Meeting of the ICCP. Commission III, ICCP News, 30, pp.28, (2003)

Minutes of the 57th Meeting of the ICCP. Commission III, ICCP News, 36, pp.37, (2005)

Minutes of the 58th Meeting of the ICCP. Commission III, ICCP News, 39, pp??.(2006

Objectives

The WG was created in 2005 (Patras, Greece) to identify all the organic and inorganic components in fly ashes by using optical microscopy and to establish an ICCP classification that can be accepted internationally.

Activities

Further activity

During the round robin exercises the fly ash components will be classified following the main criteria:

i)- To differentiate Organic and Inorganic Components.

ii)- For the organic components it is necessary to take into account their optical texture, their fused or un-fused character, their structure and morphology, and their origin (coal, others) and in this specific order.

iii)- For the inorganic components, these should be classified into two categories: metallic and non-metallic components.

It is agreed that the participants will provide a description of the particles included in the exercise. The convenor should send out two pictures of each fly ash component included in the exercise, recording the anisotropy/isotropy of the particle.

The inertinite in combustion W.G. was established in 1995 at the Krakow Meeting as the natural evolution of the former Reactive Inertinite W.G., which mainly dealt with the behaviour of inertinite under the conditions prevailing in coke ovens. Once that W.G. accomplished the objectives pursued, it was decided to redirect it to the study of the transformations undergone by inertinite in conditions similar to those occurring in pulverised fuel (p.f.) boilers, taking advantage of the expertise acquired, but also bearing in mind that the conditions at which both processes operate strongly differ from each other, in heating rates, atmosphere, particle size, etc.

The combustion reactivity of inertinite has been the subject of a number of studies, most of which made use of the experience achieved from the coking industry. These studies coincide in that the plasticity of inertinite when submitted to p.f. conditions is enhanced compared to carbonisation, and that most of the inertinite undergoes changes which are identifiable with the aid of an optical microscope. Experience has also shown that the inertinite-rich coals may burn as efficiently as vitrinite-rich ones and therefore the concept of reactivity is not necessarily linked to that of fusibility. On the other hand, inertinite behaves in a variable way, due to its inherent heterogeneity, that is difficult to systematise, whereas the behaviour of vitrinite follows rather defined trends depending on the rank of the coal. Although the subject “reactivity of inertinite” may be well beyond the scope of an ICCP W.G., there are a number of points where petrology may make a contribution to the understanding of inertinite behaviour in the boilers, provided that we are able to establish the relevant features to be considered.

It is generally accepted that combustion proceeds through two main steps. The first one is the devolatilisation of the particle, which yields a solid residue commonly referred to as char, and the second one is the combustion of the char. As the second step is more time consuming than the first one, it might be considered that the combustion behaviour of the inertinite would depend on the structural rearrangements taking place during the first short pyrolysis stage. The chars will therefore provide an excellent starting point to describe the behaviour of inertinite during combustion.

Objectives

The objectives of this working group can be then summarised as:

Description of the optical appearance of the inertinite in chars
Establishment of petrographic criteria able to group those materials which are likely to behave in a similar manner during combustion
Determination of the relationships between the optical properties of inertinite in coals and chars

Activities

The Automation Working Group uses programmable devices to automatically collect data on coal. Originally, these data were generated by photometers and gathered from DVM?s (digital volt meters), but now they are likely to be digital images from CCD (charge couple device) cameras. Usually, there is no attempt to identify the maceral source of the measured response, and so novel ways of interpreting reflectance profiles, using probability plots for example, have emerged.

Two laboratories have legitimized their automated devices by successfully completing the ICCP Accreditation exercise. This implies that the methods used to interpret automatically collected reflectance data, when applied to a suite of single-coal-samples of known random reflectances and group maceral contents, give results that are similar to the results of the Accredited Petrographers. In other words, automated petrographic systems can characterize coals using criteria and terminology similar to manual petrography.

Participation by Automation Working Group members using their automated devices in the analytical activities of the Blends WG has been encouraged, to not only generate unique data for that WG, but to also hone our skills in the interpretation of automated data of blend composition.