The manufacturing of clinker and cement is – like other industrial activities – a resource and energy-intensive process. The substitution of primary resources by suitable alternative materials (fuels and raw materials) is therefore an issue of growing concern for cement manufacturers. The ecologically and economically driven increase in the use of alternative materials comes with a continuous development in the respective environmental and technical requirements. In this context, the European Waste Framework Directive (2008/98/EC) and the Industrial Emissions Directive (2010/75/EU) play a decisive role. Moreover, the recently published legally binding conclusions on the Best Available Techniques (BAT, decision 2013/163/EU) are worth mentioning in this context. This document clearly names the use of suitable alternative materials as a BAT procedure for the cement industry.
Use of waste as alternative fuels
The major fossil fuel used in the European cement industry is still petcoke. However, by 2009 some 28% of the overall thermal energy demand of the European cement industry was gained from suitable alternative materials.
Some member states have reached substitution rates above 60%. The current situation in the European cement industry already leads to a replacement of about 6.6 million t of coal each year.
Taking into consideration the fact that a remarkable amount of waste is still landfilled in the EU, the fractions from mixed industrial and municipal waste in particular can be seen as a potential resource for increasing the overall substitution rate in the European cement industry. However, before these materials can be used as alternative fuels in cement kilns, they usually have to be processed and pre-treated. Unprocessed mixed municipal waste is not a suitable material for the clinker manufacturing process.
European cement kilns that utilise waste as a fuel are subject to the European Directive on Industrial Emissions (2010/75/EU). This directive was published in the official journal of the EU on 17 December 2010. It had to be implemented by all member states of the EU into the respective national law by 7 January 2013.
Besides the general requirements on the environmentally safe and sound operation of industrial facilities, annex VI of the Industrial Emissions Directive (IED) covers the requirements of dedicated waste incinerators as well as the so called co-incineration plants (i.e. industrial facilities such as cement kilns using waste fuels). In so doing, the IED harmonises the European legislation for the incineration of waste. The co-incineration plants have to be operated according to the same environmental standards as the incinerators.
The major idea of the IED and its annex VI is based upon the regular control and monitoring of the emissions of the respective industrial facilities (incineration and co-incineration plants).
The idea of co-processing and the European waste hierarchy
A further important legal document concerning the use of alternative materials in the cement industry is the European Directive on Waste (Waste Framework Directive, 2008/98/EC). Article 4 of this directive lays down the five-step waste hierarchy, which has to be applied as a priority order as follows:
- Preparing for re-use.
- Other recovery, e.g. energy recovery.
In principle, this waste hierarchy has to be taken as a priority order for all constituents and the best environmental option in waste legislation and policy. Simultaneously, it is mandatory for the member states to take measures that encourage the options that deliver the best overall environmental outcome.
Using alternative materials in the clinker burning process offers the unique opportunity of a simultaneous energy and material recovery of the complete intake material. In order to distinguish these specific characteristics of the clinker burning process from co-incineration in a normal boiler, the cement industry has developed the idea of co-processing. This specific term is targeted at describing the simultaneous use of waste as a raw material and as a source of energy to replace natural resources (material recycling) and primary fossil fuels (energy recovery) in the clinker burning process. Based upon this idea, it is justified from the cement industry’s point of view to move co-processing into a higher position in comparison to the classic co-incineration where usually slags, ashes or other waste constituents are generated.
Co-processing as a BAT-procedure
As an almost waste-free industrial process, clinker burning is highly suitable for applying the idea of co-processing. By doing so, the demand for natural resources is reduced, overall pollution is minimised and additional efforts for optional after-treatment of waste or the necessity of landfilling are avoided. Thus, co-processing is fully in line with the subject matter in the scope of the European Waste Framework Directive: it preserves natural resources, reduces emissions, uses the intake material in the product and recovers more than 80% of the energy in the fuels.
The careful selection and – if necessary – pre-treatment of alternative materials ensures that the co-processing of waste does not result in any harmful emissions to the environment. This is also safeguarded by the strict emission limits as they are laid down in the IED. In addition to these strict legal requirements, quality control schemes are implemented onsite in order to monitor in particular the intake of trace elements into the system. By doing so, unsuitable materials can be prevented from entering into the clinker burning process.
Based upon this positive impact, the co-processing of alternative fuels in the clinker burning process has been considered to be BAT for the cement industry in Europe. This is clearly stated in the legally binding BAT conclusions that were published recently by the European Commission (Decision 2013/163/EU).
This positive assessment encourages the European cement industry to continue its efforts to further increase the share of suitable alternative fuels. Thus, besides all other advantages, the industry can also deliver a valuable contribution to environmentally sound waste management.
This article is based on a presentation held at the ECRA seminar ‘Fuels of the Future’ on 11 – 12 May 2013 in Split.
Written by Martin Oerter, VDZ, Research Institute of the Cement Industry. This is an abridged version of the full article, which appeared in the June 2013 issue of World Cement. Subscribers can view the full article by logging in.
Read the article online at: https://www.worldcement.com/europe-cis/28052013/legal_background_alternative_fuel_use_cement_industry_194/