UNIVERSITY OF ZAGREBU FACULTY OF CHEMICAL ENGINEERING AND TECHNOLOGY POLYMER SCIENCE AND TECHNOLOGY Lecturers: Dr. sc. Zlata Hrnjak-Murgić, Full Prof. Zagreb, November 2011
POLYMER MATERIALS Environment Ü Sustainable development Ü Polymer Waste Management ♦ Mechanical Recycling ♦ Chemical Recycling ♦ Energy Recover ♦ Composting Zagreb, November 2011
Environment Sustainable development n It is necessary to enable the development of society, but without the negative and harmful impact on environment, natural resources and society. n SUSTAINABLE DEVELOPMENT In order to realize this idea it is necessary to connect the interests of society, economy and environment Zagreb, November 2011
Environment Sustainable development - history n 1972 – Stockholm declaration q n 1992 - Earth Summit in Rio de Janeiro the UN conference q 1 st global Conference -For the first time environmental protection is defined as a global problem. § n 1987 n 2002 - The UN World Commission on Environment & Development q released the book "Our Common Future“ -Adopted the concept of sustainable development / consumption Specifically devoted to environmental § outcome of the summit was agenda for 21 st century- Agenda 21“ – World Summit on Sustainable Development in Johannesburg adopted the Millennium Development Goals q Zagreb, November 2011
Environment Sustainable development Millennium Development Goals n n n n Eradicate extreme poverty and hunger Achieve universal primary education Promote gender equality & empower women Reduce child mortality Improve maternal health Ensure environmental sustainability Develop a global partnership for development Development of society and impact on the environment: Zagreb, November 2011 Ø Ø Ø Ø Ø Population growth, Urban Planning, Water and air quality, Climate change, Energy use, Human health, Waste management, Food production, Manufacture of chemicals and materials.
Environment Sustainable development n Population Growth is considered one of the biggest problems affecting the stability of the sustainable development / consumption n Total population 2000 – 6. 1 billion Growth of population and level of economic development is equated with the quality of life. n Impact on increased consumption. Figure 1 - Population growth from 1950 to 2005 and growth projections to 2050. (United Nation 2006) Zagreb, November 2011
Environment Sustainable development è Ø Urban Planning in future is expected the growth of cities and the increasing number of mega cities. Impact on increased consumption èIn 2030 it is expected that 60% of the world's population will live in cities. n. It will become a source of health problems, due to: Ø water and air quality, Ø waste management, Ø energy use, Ø human health, Ø climate change Zagreb, November 2011
Environment Sustainable development n Water Quality n Availability of water requires a sufficient amount of water for normal human needs. n The amount of water of at least 20 L/day/person from a source located within 1 km. n The depletion of sources of drinking water: q q Quantity (due to excessive exploitation, drying rivers. . ) Quality as a result of pollution. Figure 2 - Availability of water in regions of the world. (2001. m 3 of water /person/ year) Zagreb, November 2011
Environment Sustainable development n n Human Health According to the World Health Organization (WHO) - polluted environment causes 25% of all diseases in the world. Around 900 million people lack access to clean water or sanitation due to environmental degradation Region % of population lacking improved water supply % of population lacking improved sanitation In 2000 population (in millions) Asia 19 52 3, 683 Africa 38 40 784 Latin America i Caribbean 15 22 519 Oceania 12 7 30 Europe 4 8 729 Zagreb, November 2011
Environment Sustainable development Figure 3 - Major diseases caused by environmental pollution, the total population Ostale bolesti, 34 % Crijevne bolesti, 16 % Infekcije dišnih puteva, 11 % Neuro-psihijatrijski poremećaji, 7 % Perinatalni uvjeti, 3 % Kardiovaskularne bolesti, 7 % COPD, 3 % Ne namjerne povrede, 6 % Ukupno karcinom, 4 % Malarija, 5 % Nesreće u cestovnom prometu, 4 % *COPD= kronične bolesti, dišnih puteva Zagreb, November 2011
Environment Sustainable development n Energy and Climate n High energy consumption in: q q n industry transport, commercial buildings population. Energy consumption is one of the main reasons for the emergence q q of greenhouse gases that cause climate change Figure 4 - Energy consumption from 1973 to 2006 Zagreb, November 2011
Environment Sustainable development Emissions of CO 2 per capita North American Europeans Japanese Indian 8 t. En / year 4 t. En / year 3 t. En / year 0. 4 t. En / year (t. En is equivalent - tonnes of oil) 16 Number of tones of CO 2/year (2002) Figure 2. 5 - World consumption of fuel to Figure 5 - Emissions of CO 2 per capita due to the obtain energy from 1965 - 2005. consumption of fossil fuels and natural gas Zagreb, November 2011
Environment Sustainable development n n Toxic Chemicals n Toxic chemicals – production, use and release into the environment is a global problem -considerably increased the demand with further population growth. n The flow of chemicals - through natural and human systems, represent a risk to ecosystems and human health. Non-renewable resources Solutions: q q use of renewable sources and creating products and processes that reduce the use of materials and energy. Production of toxic chemicals (million tonnes) Oil Coal Zagreb, November 2011 (2011) Europian Commission, 1995 -2009 Nuclear Gas
Environment Sustainable development n n n The Built Environment ØThe built environment require use of very large quantities: is an environment in which we live, work, buy, educate and play. Includes everything is built: q q buildings, houses, playgrounds, street Zagreb, November 2011 Ø Ø Ø water energy and natural resources for its construction and maintenance.
Environment Sustainable development n n n Material Flows Analysis of material flow in the U. S. shows that approximately 85% of the materials used to build are of different structures and infrastructure are: cement, reinforcing steel and wood. Material 12 94 Sand 34 1. 7 Crushed stone 48 5. 9 Water Zagreb, November 2011 % of embodied energy Cement Fig. 6 Analysis of material flow in the U. S. since 1900 – 2000, no oil % material by weight 6 0
Environment Sustainable development n Sustainable consumption includes the consumption of natural resources (water, oil, . . . ) and energy in accordance with the principles of sustainable development n The greatest pressure on the sustainable development have a technological development and population growth because it increases the need for consumption and resulting in increase of quality of life. Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management There are two main problems of the plastic waste: Ø Raw material for plastic production is crude oil (non-renewable). Ø Most plastics do not biodegradate. At the landfilled plastic waste will not degrade for hundreds of years. The motivations of plastics recycling: - Plastics store the energy, which may be recovered, - Raw materials of the recycled plastics are less expensive than virgin raw materials, - Labor cost of recycling is lower than that of primary production, - High landfills expenses (voluminous), - Legislation and government regulations of the waste recycling policy. Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management Recycling of polymer waste n n Mechanical Recycling Chemical Recycling Energy Recover Composting Material recovery Incineration or fuel Biodegradation Types of plastic waste and technology for recycling • THERMOPLASTICS • Mechanical Recycling • THERMOSETS • ELASTOMERS • Chemical Recycling • Energy Recover Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management Category Mechanical Recycling Products of recycling or recovery Plastic row materials Plastic products • Depolymerization - monomers Chemical Recycling • Degradation in the blast furnace • Chemical recycling of raw materials in coke furnace • Conversion into liquid or Chemicals Gaseous state Fuels • Incineration of plastic waste to produce cement in Energy Recover cement furnace • Incineration of plastic waste for production of energy - in thermal power plants - in heating plant Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management Generation and collection of plastic waste n The sources of plastics for recycling: q q q Industrial waste; Agricultural waste (containers, pipes, sheets); Waste of hotels, restaurants, shops; Municipal waste (plastic litter collected from streets, parks, beaches); Household waste - the type of municipal waste collected from householders. Prior to recycling the plastic waste is sorted according to the coding system at the place where waste is generated Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management MECHANICAL RECYCLING of plastic waste mean the reprocessing of plastic waste by extrusion process (in melt) where polymers are melted at elevated temp. in order to obtain a new products. This is the simplest and relatively cheap recycling technology. The steps of mechanical recycling are as follows: ♦ Collecting & Sorting n. Separation u n. Large u at source of waste. Cutting plastic parts are cut by saw or shears for further processing. Shredding n. Plastics are chopped into small flakes Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management u. Contaminants separation (washing) Contaminants (e. g. paper, adhesives) are separated from plastic in cyclone separators or by § Floating Different types of plastics are separated in a floating tank according to their density. The flakes are also washed and dried u. Extrusion The flakes are fed into an extruder where they are heated to melting state and forced through the die converting into a continuous polymer product (strand). u. Pelletizing The strands are cooled by water and cut into pellets, which may be pellets used for new polymer products manufacturing. Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management Generally recycling facilities consist of the following units: - shredder / granulator – 1 - one or more units for washing – 2 - one or more units for drying – 3 - extruder - provides a better homogeneity of the material - 4 2 1 strand 3 4 Zagreb, November 2011
POLYMER MATERIALS INSPECTION Typical plastics recycling plant CHOPPING & WASHING FILTERING TO REMOVE CONTAMINSTES MOLTEN PLASTIC EXTRUDED INTO FINE STRANDS SEPARATION BY FLOTATION DRYING MELTING BY HEAT & PRESSURE PELLETIZING http: //www. maine. gov/spo/recycle/residents/whathappenstorecyclables. htm Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management CHEMICAL RECYCLING of plastic waste is a process, in which a plastic polymer is broken down (degradation) into its constituents – monomers, oligomers. . . This process is called depolymerization. The monomers is then used as raw material for manufacturing a new polymer Chemical recycling is more complex and expensive than mechanical recycling. There is a range of technology of chemical recycling : n Hydrolysis and glycolysis – depolymerization by catalysts (Na. OH, Zn. Ac). Poly(ethylene-terephtalate) (PET) may be converted into dimethyl terephthalate and ethylene glycol, which are used as starting substances to obtain the virgin PET polymer. n Pyrolysis - chemical decomposition of polymers induced by heat in the absence of oxygen n Hydrogenation – is addition of hydrogen on the double C - C bonds of oligomers (formed by degradation of polymer) - resulting in liquid fuels n Gasification - is a process of chemical and thermal degradation of plastics into oligomers (alkanes) at high temperature, where they are converted into synthetic gas during incomplete combustion Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management ENERGY RECOVER of plastic waste is a process of incineration, in which the released heat is used for production electricity or steam and/or production of alternative fuels from plastic waste. Plastics store the energy, which may be recovered by: n Municipal incineration in energy-from-waste incinerators. n Production of alternative fuels from plastic waste. The fuel can be used in various manufacturing processes and in power plant stations. n Incineration of 900 kg of MSW give the same power as the 230 kg of coal 1 lbs=2, 2 kg MSW –municipal solid waste Zagreb, November 2011
POLYMER MATERIALS ENERGY RECOVER – controlled conditions During the Incineration formation of hazardous gases (HCl, NOx…) as well as presence of heavy metals and other hazard compound can be found in ash Incineration temp. in furnaces are 850 °C – 1200 °C, while lower temp. of incineration initiate formation of dioxins and furans. Zagreb, November 2011.
POLYMER MATERIALS Polymer Waste Management COMPOSTING OR BIODEGRADATION of plastic waste is degradation of plastic by microorganisms (bacteria, fungi, …) with or without presence of oxygen (aerobic and anaerobic) on CO 2, H 2 O and compost material. Obtained CO 2 and H 2 O are used in photosynthesis during growing plants, meaning such material does not produce additional waste polymer
POLYMER MATERIALS Polymer Waste Management Source: U. S. Waste Characterization, U. S. EPA, 2007 Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management (MSW) published by the U. S. Environmental Protection Agency (EPA) Zagreb, November 2011
POLYMER MATERIALS Polymer Waste Management http: //blog. uwgb. edu/inside/index. php/log-news/04/22/dumpster-dive-results/ Zagreb, November 2011
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