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Departamento de Ingeniería Química y Tecnología del Medio Ambiente GLASS GROUP 5 Alba Calvo García Javier Caramazana Sánchez Alberto Nicolás Herrero Ricardo.

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Presentation on theme: "Departamento de Ingeniería Química y Tecnología del Medio Ambiente GLASS GROUP 5 Alba Calvo García Javier Caramazana Sánchez Alberto Nicolás Herrero Ricardo."— Presentation transcript:

1 Departamento de Ingeniería Química y Tecnología del Medio Ambiente GLASS GROUP 5 Alba Calvo García Javier Caramazana Sánchez Alberto Nicolás Herrero Ricardo Treviño Mediavilla GLASS MANUFACTURING INDUSTRY EUROPEAN COMMISSION

2 Gestión Ambiental Curso 2007/2008 European Commission 1. GENERAL INFORMATION Glass Industry: extremely diverse (Products & Manufacturing techniques) Major companies: Saint-Gobain, Danone, United Glass, AVIR. - Production EU: 29 million tonnes (1996). - Steady growth in the overall volume of sales over the last decade.

3 Gestión Ambiental Curso 2007/2008 European Commission Glass Industry Spain: Fourth European producer : 3.742.902 Tonnes of glass (2003, FEVE ) Companies: Grupo Vidrala, BA Vidrio, Group Gobain, OI Europe, PPG Industries Most of the companies are integrated in Vidrio España

4 Gestión Ambiental Curso 2007/2008 European Commission The term glass does not have a convenient simple definition. GLASS: is a hard material, transparent and fragile that ordinarily is obteined by melting silica (SiO 2 ), sodium carbonate (Na 2 CO 3 ) and limestone (CaCO 3 ). - Glasses are divided into two categories - Depending on their chemical composition, glasses are clasified in (f = thermal expansion coefficient, α) Hard glasses Soft glasses four main groups: GLASS Soda-lime glasses ( bottles, jars, tableware, window glass… ) Lead crystal and crystal glass ( decorate items, drinking glasses… ) Borosilicate glasses ( laboratory equipment, lighting, cookware… ) Special glasses ( optical glasses, glass solders, electrodes…) Soda-lime glasses, lead crystal and crystal glass, and Borosilicate glasses represent more than 95 % of all the glasses produced.

5 Gestión Ambiental Curso 2007/2008 European Commission 2. APPLIED PROCESS AND TECHNIQUES Wide range of raw materials diversity of the Glass Industry Materials: Silica sand, process cullet, post consumer cullet, sosa ash, colouring agents, feldspar, dolomite, alumina... Melting: is the central phase in the production of glass. There are numerous ways to melt glass depending on the desired product, its end use, the scale of of operation and commercial factors. Melting technique, fuel choice and furnace size will all depend on these factors. Melting techniques: - Regenerative furnaces - Recuperative furnaces - Oxy-fuel melting - Electric melting - Combined fossil fuel and electric melting - Discontinuous batch melting - Special melter desing

6 Gestión Ambiental Curso 2007/2008 European Commission Types of glass Container Glass. Flat Glass. Continuous Filament Glass Fibre. Domestic Glass. Special Glass. Mineral Wool. Ceramic Fibre. Frits.

7 Gestión Ambiental Curso 2007/2008 European Commission Raw materials for the Glass Industry are naturally occurring minerals or manmade inorganic substances. No major environmental issues associated. Emissions to Air. Dust emissions to below 5 mg/m 3. Melting The products of fossil fuel combustion and the high temperature oxidation of nitrogen in the combustion atmosphere. Volatilisation and subsequent condensation of volatile batch materials. Gases emitted from the raw materials and melt during the melting processes. 3. CONSUMPTION AND EMISSION LEVELS

8 Gestión Ambiental Curso 2007/2008 European Commission Emission to Air in the differents types of glass. Container glass. Flat glass Continuous filament glass fibre Domestic glass Special glass The higher temperatures favour higher rates of volatilisation and NO x formation, and the greater use of nitrate refining agents can result in higher NO x, SO 2, and metal emissions. 3. CONSUMPTION AND EMISSION LEVELS

9 Gestión Ambiental Curso 2007/2008 European Commission Emission to Air in the differents types of glass. Mineral wool. Ceramic fibre Emissions from melting are generally very low consisting mainly of dust from raw materials. Dust emissions are generally below 20 mg/m 3. Frits 3. CONSUMPTION AND EMISSION LEVELS

10 Gestión Ambiental Curso 2007/2008 European Commission Emission to water. Water pollution is not a major issue for most installations within the glass industry. Energy. The theoretical energy requirements for : Heat of reaction to form the glass from the raw materials Enthalpy, to raise the glass temperature from 20 °C to 1500 °C. Heat content of the gases (principally CO 2 ). 3. CONSUMPTION AND EMISSION LEVELS

11 Gestión Ambiental Curso 2007/2008 European Commission Energy in the differents types of glass. Container glass 4.5 to 7.0 GJ/tonne of glass melted and 6.5 to 9.0 GJ/tonne of finished products. Flat glass Energy levels for melting are typically 5.5 to 8.0 GJ/tonne of glass melted. Continuous filament glass fibre Energy consumption for melting is usually 18 to 33 GJ/tonne of product. Domestic glass As high as 60 GJ/ tonne of finished product. Mineral wool 3.0 to 5.5 GJ/tonne of finished product. Ceramic fibre The energy consumption ranges from 6.5 - 16.5 GJ/tonne of melt. Frits Approximately 13 GJ/tonne. 3. CONSUMPTION AND EMISSION LEVELS

12 Gestión Ambiental Curso 2007/2008 European Commission 4. TECHNIQUES IN THE DETERMINATION OF BAT The main environmental impact as a whole arises due to emissions to air from melting activities. primary techniques are those which reduce or avoid the formation of the pollutants. secondary techniques are those which act on the pollutants to render them less harmful or collect them in a form that can be reused, recycled or disposed of. Major changes affecting melting technology are usually most economically implemented if coincided with furnace rebuilds. Regenerative Furnaces. Recuperative Furnaces. Combined Fossil Fuel and Electric Melting. Discontinuous Batch Melting. Stone Wool Melting.

13 Gestión Ambiental Curso 2007/2008 European Commission 4. TECHNIQUES IN THE DETERMINATION OF BAT Electric Melting. Electric melting has important effects on pollutant emissions. Complete replacement of fossil fuels Eliminates oxides of sulphur, thermal NO x, and carbon dioxide. Dust emissions can be controlled by extraction to a dust abatement system. Not in use for production (>300 tonnes per day). Techniques for Controlling Emissions to Air from Melting Primary techniques Raw material modifications. Temperature reduction at melt surface. Burner positioning. Conversion to gas firing (or very low sulphur oils).

14 Gestión Ambiental Curso 2007/2008 European Commission Main techniques for controlling each substance emitted from melting activities and from downstream operations. Emissions to air as these are generally the most significant emissions from glass processes. 4. TECHNIQUES IN THE DETERMINATION OF BAT

15 Gestión Ambiental Curso 2007/2008 European Commission MELTING TECHNIQUE SELECTION The environmental performance of a furnace is a result of a combination of the choice of melting technique, the method of operation and the provision of secondary abatement measures. The final choice should be an optimised balance of economic and environmental advantages. Regenerative furnaces Recuperative furnaces Combined Fossil Fuel and Electric Melting Discontinuous Batch Melting Electric Melting

16 Gestión Ambiental Curso 2007/2008 European Commission TECHNIQUES FOR MATERIALS HANDLING Emissions of powder materials can be minimised by using enclosed silos Collected material can be returned to the silo or recycled to the furnace Fine materials can be stored in enclosed containers Dusty materials can be stored under cover Where materials are transported by conveyors, enclosure to provide wind protection is necessary.

17 Gestión Ambiental Curso 2007/2008 European Commission TECHNIQUES FOR CONTROLLING EMISSIONS TO AIR: These techniques include emissions related to each sector in the Glass Industry. Emissions and techniques are: Particulate matter Primary techniques: raw material changes and furnace/firing modifications. Electrostatic Precipitators Bag filters Mechanical Collectors High Temperature Filter Media Wet Scrubbers

18 Gestión Ambiental Curso 2007/2008 European Commission Oxides of Nitrogen (NOx) Combustion Modifications:reduce air/fuel ratio, reduce preheat temperature, staged combustion... Batch Formulation Special furnace Designs The FENIX Process: combustion optimisation package based on primary measures Oxy-Fuel Melting: replacement of the combustion air with oxygen Chemical Reduction by Fuel (CRF): Fuel is added to the waste gas stream to chemically reduce NOx to N 2 Selective Catalytic Reduction (SCR): involves reacting NO with ammonia in a catalytic bed Selective Non-Catalytic Reduction (SNCR): The same basis as SCR but higher temperatures

19 Gestión Ambiental Curso 2007/2008 European Commission Oxides of Sulphur (SOx) Fuel Selection Batch Formulation Dry or Semi-dry Scrubbing Fluorides (HF) and Chlorides (HCl) Reduction at Source Scrubbing Techniques Oxides of Carbon CO is rarely emitted from Glass Industry installations at a level to cause environmental concern Reduction in emission of CO 2 by reducing fuel usage

20 Gestión Ambiental Curso 2007/2008 European Commission TECHNIQUES FOR CONTROLLING EMISSIONS TO WATER Emissions to the water environment are relatively low and not specific to the Glass Industry. Water can be recycled or treated using standard techniques: Physical/Chemical Treatment.Screening Neutralisation.Skimming Aeration.Settlement Precipitation.Centrifuge Coagulation and Flocculation.Filtration Biological Treatment.Activated sludge.Biofiltration

21 Gestión Ambiental Curso 2007/2008 European Commission TECHNIQUES FOR MINIMISING OTHER WASTES Most of the activities in the Glass Industry produce relatively low levels of solid waste. The main process residues are: Unused raw materials, Melt not converted into product Waste product dust collected from waste gas streams Solid waste from waste water system Techniques for minimising wastes are: wherever practicable, prevention, minimisation of waste by primary means and recycling

22 Gestión Ambiental Curso 2007/2008 European Commission ENERGY Glass making is a very energy intensive process The choices of energy source, heating technique and heat recovery method are central to the economic performance, environmental performance and energy efficiency. The main techniques for reducing energy usage are: Melting technique and furnace design Combustion control and fuel choice Cullet usage Waste heat boilers Cullet/batch preheating

23 Gestión Ambiental Curso 2007/2008 European Commission 5. BAT CONCLUSIONS Principal characteristics Periodic rebuild of the furnaces Age of the furnace Principal emissions Dust Oxides of Nitrogen Oxides of Sulphur Other emissions from melting Downstream processes

24 Gestión Ambiental Curso 2007/2008 European Commission DUST Is considered to be the use of an electrostatic precipitator or bag filter operating, in conjunction with a dry or semi-dry acid gas scrubbing system Container glass Less than 0.1 kg/tonne of glass melted Flat glass Continuous filament glass fibre Domestic glass Level associated: 5 – 30 mg/Nm 3 Special glass Level associated: 5 – 30 mg/Nm 3 Mineral wool Level associated: 5 – 30 mg/Nm 3 Frits Less than 0.1 kg/tonne of glass melted

25 Gestión Ambiental Curso 2007/2008 European Commission OXIDES OF NITROGEN Container glass Less than 1000 mg/Nm 3. Generally equates to less than 3.0 kg/tonne of glass melted. Flat glass 500 - 700 mg/Nm 3 which generally equates to 1.25 - 1.75 kg/tonne of glass melted. Continuous Filament Glass Fibre Generally higher than 1000 mg/Nm3 and greater than 4.5 kg/tonne of glass melted. Domestic Glass In air-fuel fired furnaces are generally in the range 1500 - 2000 mg/Nm 3 which generally equates to 3.75 - 5 kg/tonne of glass melted. Special glass 500-700 mg/Nm 3. Mineral Wool 500 - 700 mg/Nm 3 which generally equates to 0.5 - 1.4 kg/tonne of glass melted. Frits 0.5 - 1.5 kg/tonne of glass melted or alternatively 500 - 700 mg/Nm 3.

26 Gestión Ambiental Curso 2007/2008 European Commission OXIDES OF SULPHUR Container glass For natural gas firing up to 800 mg/Nm 3 which generally equates to 1.2 kg/tonne of glass melted. For oil firing up to 1500 mg/Nm 3 which generally equates to 2.25 kg/tonne of glass melted. Flat glass For natural gas firing up to 800 mg/Nm3 which generally equates to 2 kg/tonne of glass melted. For oil firing up to 1500 mg/Nm 3 which generally equates to 3.75 kg/tonne of glass melted. Continuous filament glass fibre For natural gas firing less than 200 mg/Nm 3 which generally equates to less than 0.9 kg/tonne of glass melted. For oil firing 500 - 1000 mg/Nm 3 which generally equates to 2.25 to 4.5 kg/tonne of glass melted. Domestic glass For natural gas firing 200 - 500 mg/Nm3 which generally equates to 0.5 – 1.25 kg/tonne of glass melted. For oil firing 500 - 1300 mg/Nm3 which generally equates to 1.25 – 3.25 kg/tonne of glass melted. Special glass Similar to domestic glass. Mineral wool less than 600 mg/Nm3 which generally equates to less than 1.5 kg/tonne of glass melted. Frits 0.1 - 0.5 kg/tonne of glass melted which generally equates to less than 200 mg/Nm3.

27 Gestión Ambiental Curso 2007/2008 European Commission 6. EMERGING TECHNIQUES 1.Low No x burner systems - The reducing conditions above the melt or batch blanket could affect glass quality and may cause early surface descomposition. Required extra sulfate which may lead to increased SO x emissions. 2.Oxy-fuel melting - The exiting installations are still based on a conventional recuperative style cross-fired furnace. 3.Cullet and batch preheating 4.Batch formulations - Two main air emission components: particulates and fluorides. 5.Integration of frit processes 6.Flue gas recirculation - Synthetic air, based on the combination of flue gas recirculation and the use of oxygen firing.

28 Gestión Ambiental Curso 2007/2008 European Commission 6. EMERGING TECHNIQUES 7.Glasulin research program - Joint project between 17 glass companies and 4 research institutes and has the objetive for developing new methods for the reduction of sulphate levels in the batch. 7.New melter designs 8.1. The seg melter - Batch is charged into an all-electric pre-melting furnace capable of converting 75% of the raw material into glass. 8.2. The advanced glass melter - Potencial for low NO x emissions. 8.3. The plasma melter - The composition and colour of the glass can very rapidly be altered. SO x, NO x and dust emissions are negligible.

29 Gestión Ambiental Curso 2007/2008 European Commission 7. CONCLUDING REMARKS Identify those techniques which are most likely to be appropriate for a given sector. Develop a methodology for assessing the relative effects on the environment taken as a whole of emissions to different media and to the same medium. The application of oxy-fuel firing is at a relatively early stage. Some issues can only be assessed with information from the long-term use of the technique. Also the direct costs of the technique should be reassessed particularly with regard to the balance between energy savings and the cost of oxygen.


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