Life cycle assessment (cradle to gate) of a Portuguese brick

Transcription

1 Chapter 5: Monitoring and evaluation Life cycle assessment (cradle to gate) of a Portuguese brick M.I. Almeida Centro Tecnológico Cerâmica e Vidro, Coimbra, Portugal A.C. Dias & L.M. Arroja University of Aveiro, Aveiro, Portugal Baio Dias Centro Tecnológico Cerâmica e Vidro, Coimbra, Portugal ABSTRACT: The ceramic industry is a traditional sector in Portugal, with a typology of products adapted to the diverse habitat requirements. Brick is one of the most widely used materials in construction. The ceramic industry, like other sectors, generates impacts over its life cycle (from the extraction of resources until the final disposal of waste ceramics, ie from "cradle to grave"), such as consumption of resources, water and energy, air emissions, emissions to water, waste, noise, etc.. This Life Cycle Assessment (LCA) examines the stages of the brick from cradle to the customer's gate, including the process of mining and mining facilities, transport, production in factory and its later distribution to end users (base on scenarios). The methodology takes into account the ISO14040, ISO and the EPD (environmental product declaration) rules. In general, the impacts are mostly focused on air quality, particularly at the production level in the firing operation. 1 INTRODUCTION Building materials represent an important research field in the context the sustainability of construction works. Nowadays is important to know the environmental behaviour of building materials that plays an important role on the environmental responsible architecture and design of a building. The Green Paper on Integrated Product Policy (2001) proposes the use of methodologies for assessing the environmental behaviour of products that take into account their life cycle (from the mining of the raw materials, production, distribution utilisation and the management of waste). Also the CEN TC 350 is working in the development of the methodology for calculation of the sustainability of the buildings, based, in the environmental performance of the buildings, and in the EPD. The ceramic industry is a traditional sector with a significant contribution to the national economy, and a typology of products adapted to more diverse habitat requirements. Given its geological characteristics of Portugal, a soil rich in quantity and quality of raw materials, as clays and fluxes, the industrial ceramic activity was developed with many valences and diverse products, covering and flooring tiles, giving acoustic and thermal comfort inside the house. Recent developments transformed old products in multifunctional products that can incorporate other resources as organic wastes or incorporate nanomaterials so called "advanced materials". Brick is the basic ceramic product most used in the Portuguese masonry construction of buildings. 477

2 Portugal SB10: Sustainable Building Affordable to All The life cycle of ceramic construction products is long, due to the high durability of the products, and suitable for recycling. The Life Cycle Assessment (LCA) consists in the systematic analysis of the environmental impacts of products (any change in the environment, both adverse and benefic, overall or in part resulting from the product) at all stages of their life cycle, from extraction or synthesis of natural resources, through production, transportation, use and disposal of products (ie "cradle to grave"). In this paper the LCA methodology is applied to examine the environmental impacts associated to the brick production chain from cradle to the customer's gate, including the process of mining and the mining facilities, transport, brick production in factory and its later distribution to end users (base on scenarios) ie cradle to gate. The methodology takes into account the ISO14040, ISO and the EPD (environmental product declaration) rules and some databases like Ecoinvent [6], and the SimaPro software (Preconsultants, 2009). The brick selected is produced in Central region of Portugal. The ceramic industry, like many other sectors, generates over its life cycle, a series of environmental impacts (Almeida et al, 2004, 2009, Bovea et al, 2007; Timellini et al, 1998, BREF, 2008). The impacts in the production phase are related to: Emissions to air resultant from the thermal processes (drying and firing) and colt emission; Consumption of natural resources and others, energy and water; Emissions of industrial and domestic effluents; Production of waste; Noise. At the same time, the goal is to use this LCA study (cradle to gate), as the basis to obtain the Environmental Product Declaration (EPD) (ISO 14025) for this brick. The EPDs are intended to provide information for planning and assessing the sustainability ofbuildings. The declarations can also be used by the user/purchaser to compare the environmental impacts of products under certain conditions. 2 CERAMIC BRICK PRODUCTION The manufacture of bricks process goes through several stages: The first one is the mining/quarrying of raw materials, followed by the storage of raw materials, raw materials preparation, shaping, drying, firing, packing and subsequent treatment. Dry preparation and semi-wet preparation are used in the manufacture of bricks. The combined processes of mixing and kneading bring about a homogenisation of the mass to obtain a good plasticity. The prepared mixed clay are stored in large volume facilities, ageing and souring for further homogenisation. Water may be added in this stage. Then the mixed clay is submitted to a shaping process such as, extrusion, and soft-mud moulding, depending on the kind of clay, the water content and the desired product. After this stage, the green brick goes to the drying process. This operation occurs in tunnel and fast dryers, during 8 up to 72 hours at a temperature of 75 up to 90 ºC. One of the most important operations of the brick making process is the firing. This operation is done in tunnel kilns mainly in an oxidising atmosphere. The ware to be fired passes through the kiln on a series of kiln cars. Dried bricks are placed directly on the tunnel kiln car. The ware to be fired is heated up to a maturing temperature of between 800 and 900 ºC. Following the necessary body formation time of between two and five hours at maturing temperature, the ware is cooled down according to a plan to 50 ºC. The firing time of brick is 17 to 25 hours. In the final stage the bricks are sorted during the unloading of the kiln or the tunnel kiln car automatically or manually, packed and palletised for transportation to a shipping unit. 478

3 Chapter 5: Monitoring and evaluation 3 LCA METHODOLOGY AND RESULTS 3.1 Goal and scope definition The aim of this work was to identify and assess the environmental impacts associated with extraction, production, and distribution (based in scenarios) of ceramic brick produced in Portugal (from cradle to gate). All inputs to the system related with energy consumption (fuel and electrical power) and natural resources (clay and water) were included. The system outputs comprise emissions into the atmosphere and into water and the generation of waste (hazardous and non hazardous waste) from the processes (extraction, transport and production). The end of life and the impacts of the waste management transport and treatment were not in the scope of this study. 3.2 Functional Unit and system boundaries The functional unit used was 1 kg of brick ready to be sold (for a brick 11 (dimensions 30*20*09 cm), 1000 kg is equivalent to 14,6 m 2 ). The phases included in the system are the extraction of raw materials, brick production and distribution of the final product to customers (scenario 100 km). A cut-off rule was established in order to decide which materials associated to these phases should be included within the boundaries. Thus, the materials that represented less than 0.5% of the functional unit were left outside the boundaries. The phases corresponding to consumer use and final disposal of the product were also excluded, as well as transport and final disposal of industrial waste. The construction phases of the plant and remaining infrastructure, production of manufacturing equipment, personal activities were also excluded. The figure 1 represents the life cycle phases and system boundaries of the Portuguese brick material under study (the dashed boxes were not included in the study). Extraction Phase Raw Materials Clay Extraction Additives and Auxiliaries Manufacturing Production Phase INPUT Natural Resources Energy Brick Production Earths Grinding and Mixing Extrusion Drying Firing in Tunnel Kiln Handing and Sorting Packaging and Storage OUTPUT Waste Emissions to Air Waste Water Soil Contamination Maintenance and Services Use Phase Transportation to the Customers Leaching End of Life Phase Landfill, Recycling, etc. Figure 1. The life cycle phases and system boundaries of the brick material 479

4 Portugal SB10: Sustainable Building Affordable to All 3.3 Quality of the data Data for the brick production process refer to the year 2008 and were collected by the Technological Center of Ceramic and Glass (CTCV) from industrial companies located in central Portugal. Data from literature sources and from the database "ecoinvent were used for the remaining processes included in the boundaries. The "cut-off rules" were also used for the processes and activities that don t contribute more than 0.5% for the environmental impact. 3.4 Inventory analysis The parameters used to describe the environmental burdens of the processes were divided into inputs and outputs. Inputs include materials/products, chemical substances and preparations, fuels, resources (used as raw material or energy) and electricity. The outputs include materials/products, energy, air emissions, waste water emissions and waste. The processes, inputs and outputs had been modelled with the SimaPro software application following the guidelines set out in the ISO and ISO standards. The environmental burdens during the stages (extraction, manufacturing and transport) vary depending on the type of material production, and are generally distributed as shown in Table 2 and 3, which present respectively the inputs and the outputs for the production of 1 kg of brick. Table 2. Primary LCI data in terms of inputs (data for the functional unit: 1 kg of brick) Units Inputs Clays 1.22 kg Water (well) 9.55E-05 m 3 Domestic water 2.25E-06 m 3 Electricity 3.38E-02 kwh Natural gas 1.10 MJ Diesel 2.14E-02 MJ Lubricating oils 2.92E-06 kg Packing film 1.14E-04 kg EUR pallet 1.61E-05 p Steel castings 9.55E-06 kg Product transport 100 km 480

5 Chapter 5: Monitoring and evaluation Table 3. Primary LCI data in terms of outputs (data for the functional unit: 1 kg of brick).. Units Outputs CO 5.71E-04 kg CO2 6.50E-02 kg NO 4.35E-05 kg SO2 3.56E-05 kg F 7.67E-07 kg As 1.55E-08 kg Cd 7.51E-09 kg Cr 2.55E-08 kg Cu 4.21E-10 kg Hg 3.75E-09 kg Ni 3.60E-08 kg Pb 7.50E-08 kg Zn 1.44E-08 kg HCl 7.49E-07 kg PM E-05 kg NMVOC 1.97E-05 kg CQO 5.31E-09 kg SST 1.81E-08 kg Oils 1.38E-09 kg The full inventory also includes the transport of the final product brick to consumer consider a scenario of 100 km. 3.5 Life cycle impact assessment Environmental indicators were obtained for the impact categories shown in Table 4, together with the indicator that quantifies them. The impact categories correspond to the proposals of the EPD ( and the characterization factors were those suggested by CML method [ Table 4. Impact categories and units considered in the study (data for the functional unit: 1 kg, including 100 km distribution to the customer) Impact category Unit Total Global warming (GWP100) kg CO2 eq 1.41E-01 Ozone layer depletion (ODP) kg CFC-11 eq 1.67E-08 Photochemical oxidation kg C2H4 7.50E-05 Acidification kg SO2 eq 5.44E-04 Eutrophication kg PO4--- eq 7.24E Interpretation In the category global warming, the main contribution comes from the production phase namely the burning of natural gas in the stage of drying and firing. Transport and the clay mine process are less relevant. In the category of the ozone layer depletion, the profile of contributions seem to be mainly due to the emissions from the combustion of diesel in the transports associated to clay consumption, brick storage and brick distribution. The category photochemical oxidation is predominated by drying and firing processes in brick production that emit nitrogen oxides (NOx), sulphur oxides (SOx), carbon oxides (COx) and hydrocarbons during the combustion of natural gas and also by combustion of diesel in the 481

6 Portugal SB10: Sustainable Building Affordable to All transport. The emissions of SOx given off during the production of the electrical power used by the machinery in brick production play also an important role for this impact category. Acidification is mainly due to NOx and SO2 emitted during the drying and firing of the ceramic brick and in the combustion of fuels in transports. Eutrophication is mainly due to NOx emitted during the combustion of the natural gas used in drying and firing of the ceramic brick and in the combustion of fuels in transports. 4 CONCLUSIONS This LCA study reports inventory data and impact assessment associated with the manufacture of ceramic bricks from cradle to gate, including ceramic brick distribution. (with a scenario of 100 km). Many of the impacts of the brick manufacture are associated to the air emissions in the production stage. The reduction of mass and the temperature of firing of ceramic bricks, using specific clays and organic mass additives, is one possibility to reduce the environmental impacts and improve the sustainability of the ceramic bricks. The building construction industry will be, in the next future, focused on the Environmental Product Declaration (ISO 14025) for the different materials used in building. This is the case of the Portuguese Ceramic Industry Association, promoting decisions based in the life cycle of products, in order to build more environmental friendly constructions. 5 ACKNOWELEGEMENTS The authors which to tank to APICER and QREN (National Strategic Reference Framework) for the financial support. REFERENCES Almeida M.; Vaz S.; Baio Dias [et al]; Dezembro de 2004, Impactes Ambientais e Comércio de Emissões, Indústria Cerâmica- Um caso de estudo, ed. APICER - Associação Portuguesa da Indústria Cerâmica, Coimbra, Almeida, M.; Machado, S., 2009, Novos Critérios Propostos para atribuição do Rótulo Ecológico a Produtos de Pavimento e Revestimento, Revista KÉRAMICA nº 294, págs Bovea MD, Saura U, Ferrero JL, Giner J., 2007, Cradle-to-gate study of red clay for use in the ceramic industry. Int J LCA 2007;12(6): Ecoinvent. 2009, The life cycle inventory. Data V. Switzerland: Swiss Centre for Life Cycle Inventories;. European Commission, Institute for Prospective Technological Studies, 2008, BREF: Reference document on best available techniques in the ceramic manufacturing industry., Sevilla, Spain; SimaPro , software. Pre consultants, Amersfoort, The Netherlands. Timellini, G. Palmonari, C., cremonini, 1998, Life cycle assessment of ceramic tiles. General Considerations, Ceram Acta vol. 10 nº 1, pp