Ökologische Auswirkungen einer Vortrocknung von Kohle zum Einsatz in der indonesischen Textilindustrie

Published as part of the project EnaTex

Authors: Sven Gärtner, Guido Reinhardt, Maximilian Breyer

The joint project ‘Energy and Sustainability in the Textile Industry: Energy Efficiency and Renewable Energies in Partnership for Climate Protection’, funded by the Federal Ministry of Education and Research (BMBF) from 2021 to 2025, aims, among other things, to support the Indonesian textile industry on its path to a sustainable future. As part of this project, ifeu is responsible for the ecological assessment of current processes in the Indonesian textile industry and measures to increase sustainability. This includes, among other things, the optimisation of processes, the substitution of technologies and the comparison of textile products. The questions included in the ecological assessment were defined by the project partners.

One of these questions was formulated by the Institute for Future Energy and Material Flow Systems (IZES) and deals with the environmental impact that waste heat-based pre-drying of coal as an energy source could have before its use in the Indonesian textile industry. The background to this is that heat generation in Indonesian textile factories is currently often achieved by directly burning Indonesian coal in heating plants. Depending on the deposit, Indonesian coal has properties that range widely between lean coal (semi-anthracite according to the ASTM International classification) and soft lignite [Belkin & Tewalt 2007; BGR 2009]. The coal used domestically has a rather low calorific value, which is similar to that of lignite. Accordingly, it is often characterised by a fairly high water content, which is further increased in some cases by the coal being exposed to the weather during transport and storage. At the same time, the textile industry generates a large amount of waste heat that has not been used or has been used very little to date. In future, this waste heat could be used to pre-dry the coal, which would increase its calorific value and enable more efficient combustion, potentially leading to fuel savings.

The aim of the study is therefore to investigate the extent to which pre-drying coal using waste heat (before it is used for energy in the Indonesian textile industry) can help to save fuel and reduce environmental impact. The main focus is on estimating the potential coal savings and their effects on the environment for different initial water contents and degrees of drying, i.e. independently of company-specific processes.