Waste to Energy Technology

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June 2015 Exchange Issue 16 Waste to Energy Technology Guest Authors: Eng. Maffeo Felice Giovanni and Eng. Amelio Stefano Engineers at IREN Ambiente, felicegiovanni.maffeo@ gruppoiren.it and stefano.

The WtE sector has undergone a rapid technological development over the last 10 to 15 years.

A continual process development is ongoing: at the moment, the sector is exploiting techniques which aim to limit costs and to improve environmental performance.

Incineration processes allow not only recovering energy, but also mineral and/or chemical content from waste.

1 June 2015 Exchange Issue 16 Waste to Energy Technology Guest Authors: Eng. Maffeo Felice Giovanni and Eng. Amelio Stefano Engineers at IREN Ambiente, gruppoiren.it and 1 Introduction Waste to Energy (WtE) is now an available and well-known procedure to treat a very wide range of waste. The WtE sector has undergone a rapid technological development over the last 10 to 15 years. This change has been driven in order to control industries policies, and in particular, imposing limits on pollutants produced by individual installation. A continual process development is ongoing: at the moment, the sector is exploiting techniques which aim to limit costs and to improve environmental performance. The intention of waste incineration is to treat wastes so as to reduce their volume and hazard, destroying potentially harmful substances that are, or may be, released during incineration. Incineration processes allow not only recovering energy, but also mineral and/or chemical content from waste. Basically, waste incineration is the oxidation of the combustible materials contained in the waste. Waste is generally a highly heterogeneous material, consisting essentially of organic substances, minerals, metals and water. The incineration produces flue-gases whose energy is in the form of heat. The organic fuel substances in the waste burns once the necessary ignition temperature is reached and there is enough oxygen. In this condition the combustion process takes place. Referring to 2011, among the 27 European Member States (MS), the amount of Municipal Solid Waste (MSW) suitable for thermal waste treatment is approximately 253 million tons. The scale of use of incineration as a waste management technique (i.e. percent of solid waste treated via incineration) varies significantly from place to place ranging from zero to 65%. The average value in the same year was approximately 20 %. The target of thermal treatment is to provide an overall environmental impact reduction that might arise from the waste. WtE usually includes a complex set of interacting technical components which, when considered together, effect an overall treatment of the waste. Each of these components has a slightly different main purpose, the main ones as below: volume reduction of residues and destruction of organic substances evaporation of water to recover energy evaporation of volatile heavy metals and inorganic salts production of potentially exploitable slag removal and concentration of volatile heavy metals and inorganic matter into solid residues

Page2 residues, sludge from waste water treatment minimizing emissions Basics on the technology and IREN references The structure of a WtE plant may include the following operations.

2 Page2 residues, sludge from waste water treatment minimizing emissions Basics on the technology and IREN references The structure of a WtE plant may include the following operations. Some details of these main operations are described as follows: incoming, waste reception and storage of waste; pretreatment of waste, where required; loading of waste into the process; thermal treatment of the waste; energy recovery; flue-gas cleaning residue management; flue-gas monitoring and stack outlet; waste water control and treatment; ash management and treatment; solid residue discharge/disposal. Figure 1: Waste to Energy plant operations Delivery and bunker Incineration and steam generation: The waste delivery area is the location where the delivery trucks, trains, or containers arrive in order to dump the waste into the bunker. In this phase the waste is usually subject to a visual control, to check for radioactivity followed by the weighing operations. The dumping occurs through openings between the delivery area and the bunker. Tilting and sliding beds may be used to help waste transfer to the bunker. The openings can be locked, and therefore also serve as odor and seal locks, as well as fire and crash-protecting devices. The bunker is a waterproof, concrete bed. The waste is piled and mixed in the bunker using cranes equipped with grapples. The mixing of waste helps to achieve a balanced heat value, size, structure, composition, etc. of the material dumped into the incinerator filling hoppers. The bunker area and the feeds system are equipped with fire protection system. Grate incinerators and recovery boilers usually have the following components: waste feed chute; waste feeder; incineration zone; main incineration zone separator for large kernels; bottom ash discharger; riddling; boiler ash remover; primary air supply; secondary air supply; The incineration grate should guarantee a good distribution of the incineration air into the furnace, according to combustion requirements. A primary air blower forces air through small grate layer openings

3 Page3 into the fuel layer. More air is generally added above the waste bed to complete combustion. The burning waste remains for almost an hour on the incineration grate. Figure 2: WtE combustion and recovery boiler typical diagram Figure 3: Boiler and ash remover WtE Plant (Parma)

4 Page4 Flue Gas Treatment (FGT) - gas cleaning chimney: The FGT is designed to clean the combustion gases coming from grate and boiler to reach the environmental performance stated by the Authority in accordance to the: Incineration Directive 200/76/EC. Individual components of a Flue-Gas Treatment system are combined in different ways to provide an effective overall system for the treatment of the pollutants in flue-gases. Below is a summary of some application in the WtE sector. The applied system exploits different technologies according to the waste streams. For example in the WtE plant in Parma, the flue-gases treatment is designed in five single steps: - First Dry-type reactor for the injection of lime and activated carbon in the flue-gas stream; - Bag filters for the collection of combustion by-products and reaction products from flue-gas treatment reactions; - Second Dry-type reactor for the injection of sodium bicarbonate and activated carbon in the flue-gas stream; - Bag filters for the collection of combustion by-products and reaction products from flue-gas treatment reactions; - DeNox Selective Catalyst Reactor for the reduction of nitrogen oxides concentration. Table 1: Number of MSWT plants withvarious flue - gas treatment systems WtE plants by-products The waste to energy treatment produce refuses, as by product, in consequence of: combustion process (metal debris and scraps); flue-gas treatment FGT (fly ashes and compounds of sodium). The refuses, almost 21% of the inlet waste in weight, are the residual fraction of the waste: once these residuals are dropped from the grate, they are cooled down and transferred to a special waste pit. During the transfer, a set of electromagnets separate the metal debris in order to recycle. The scraps are then treated by experienced companies which are able to recycle the resulting material and transform them into building material. Due to the fact that the residuals from flue-gas treatment (fly ashes and compounds of sodium) are hazardous pollutants according to the European Waste Catalogue (EWC), they are transferred to authorized facilities for disposal. According to the Italian law, these facilities are required to submit an environmental authorization, which in Italy is called AIA Autorizzazione Integrata Ambientale. Energy recovery: The majority of the energy produced during combustion is transferred to the flue-gases which are collected into a recovery boiler, in order to produce superheated steam that is inputted in a steam turbine

Page5 power generator. The characteristics of steam (pressure and temperature) or hot water (district heating DH) are determined by the local energy requirements and operational limitations.

5 Page5 power generator. The characteristics of steam (pressure and temperature) or hot water (district heating DH) are determined by the local energy requirements and operational limitations. The following factors have to be taken into account when determining the local design of an energy recovery system: Electricity national grid or industrial network and plant selfconsumptions; price of electricity significantly influences investment; subsidies or loans at reduced rates can increase investment; technical requirements: voltage, power, availability of distribution; Heat the end-users: to communities (DH) or to private industries; geographical constraints; delivery piping feasibility; duration of the demand, duration of the supply contract; obligations on the availability of the heat supply; steam/hot water conditions: pressure (normal/ minimum), temperature, flowrate; season demand curve; subsidies can influence economics significantly; Figure 4: Steam Turbine Power Generator WtE Plant (Parma) IREN has developed its own practice in WtE plant in northern Italy. The following images show the main references:

6 Page6 Figure 5: Aerial view of Tecnoborgo WtE Plant (Piacenza) Figure 6: Aerial view of PAI WtE Plant (Parma)

Page7 Figure 7: Aerial view of Gerbido WtE Plant (Turin) Key process data: In Europe, the waste treated in WtE plants is mainly the non recyclable share of the separated waste.

In order to set the size of the plant, a key figure is the range of low heating value (LHV) of waste, which is identified through its chemical compounds.

7 Page7 Figure 7: Aerial view of Gerbido WtE Plant (Turin) Key process data: In Europe, the waste treated in WtE plants is mainly the non recyclable share of the separated waste. This amount is usually evaluated in term of tons/year (t/y). In order to set the size of the plant, a key figure is the range of low heating value (LHV) of waste, which is identified through its chemical compounds. LHV is the energy release that is reported in the literature of continental Europe (Niessen, W., 2002). With these characteristics (waste capacity and LHV), it is possible to estimate the electrical and thermal supply in the plant design. It is also important to evaluate environmental benefits in terms of fuel saving, normally expressed in toe (tonne of oil equivalent) per year. The table below shows the design characteristics of three implemented WtE plants in Italy: Table 2: characteristics of three implemented WtE plants in Italy

Page8 Live example from monitoring equipment of air pollutants The updated application in WtE monitoring system at the stack is based on Fourier Transform InfraRed (FT-IR).

8 Page8 Live example from monitoring equipment of air pollutants The updated application in WtE monitoring system at the stack is based on Fourier Transform InfraRed (FT-IR). Some of the infrared radiation is absorbed by the sample and some of it is passed through (transmitted). The resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample. Knowing that each molecular fingerprint is unique, the infrared spectroscopy is useful for several types of analysis. So, the information provided by FT-IR are: the quality or consistency of a sample and the amount of components in a mixture. Check the following links in order to see the real time values of IREN plants: www. irenambiente.it (as an example). These following screenshots present an example of the charts published daily on the IREN website containing the list of information that the end user can find: Table 3: Examples of live monitoring charts of PAI WtE Plant (Parma) Table 4: Examples of live monitoring charts of PAI WtE Plant (Parma) 2

Page9 Table 5: Examples of live monitoring chart of Gerbido WtE Plant (Torino) Table 6: Examples of live monitoring charts of Gerbido WtE Plant (Torino) 2 Benefits in terms of heat and electricity

However, the generation of electricity is limited by: the high-temperature corrosion that may occur in the heat conversion area due to the presence of certain materials, including chlorine, in the

9 Page9 Table 5: Examples of live monitoring chart of Gerbido WtE Plant (Torino) Table 6: Examples of live monitoring charts of Gerbido WtE Plant (Torino) 2 Benefits in terms of heat and electricity The main benefit in WtE is using waste as fuel to produce thermal and electric energy, and consequently a saving of traditional fuel. However, the generation of electricity is limited by: the high-temperature corrosion that may occur in the heat conversion area due to the presence of certain materials, including chlorine, in the waste fouling of the boiler. Above approximately 600 to 800 C the ashes are sticky due to the presence of some smelting substances. The steam generation parameters (and hence electrical efficiency) of incineration plants are therefore limited. A maximum steam pressure of 60 bar and a temperature of 520 C can be considered the maximum at present. These limitations can be dealt with through the adoption of special and expensive measures to limit corrosion. For electricity production from MSW, the typical features of superheated steam conditions are 40 to 45 bar and 380 to 400 C. Only for particular conditions due to the presence of hazardous waste, steam conditions are generally less than 30 bar and 300 C in order to avoid corrosion risk by acid fluegas. Average rates of electricity production and distribution referred to each inlet MW by waste combustion: in case of no District Heating: - from 22% to 28% in case of District Heating - from 15% to 20% Considering that, in both cases, the WtE process electrical self-consumption is approximately 15% of the electricity produced. Average rate of thermal production and distribution, referred to each inlet MW by waste combustion, is estimated between 50% and 55%.

10 Page10 Environmental implications and social acceptability According to the U.S. Environmental Protection Agency, waste-to-energy plants produce electricity with less environmental impact than almost any other source of electricity. Clearly, today s wasteto-energy plants are nothing like those old, polluting incinerators of the past. While the combustion of waste as a method of disposal dates back centuries, it was not until 1975 that the combustion of waste for the purposes of generating energy became commercially available in the U.S.A. In fact, the first commercial waste-to-energy plant opened in 1975 and still operates in Saugus, Massachusetts. It was recently however, updated with stringent emissions control systems in accordance with the most stringent state and federal standards. Waste-to-energy plants today are much more advanced than the incinerators dating years back. First, as their name implies, waste-to-energy facilities extract energy from the trash, whereas incinerators only attempted to reduce the volume of the trash. Waste-to-energy plants use high temperature combustion, as much as possible, to reduce the volume of the trash by 90%, decreasing the need for valuable landfill space. IREN, in its plants implementations has had to ensure the social acceptability of WtE plants. The main aim is to persuade the third party. Therefore, it is very important to meet the people residing in the area and clearly detail the project s characteristics: WtE methods, technologies and processes. It is very important to show the residents the social advantages of WtE. The most important of which: high level of process and environment monitoring,; a really proven worldwide technology,; fuel for energy is obtainable cheaply,; current landfill material used as fuel.; Economics of the technology The economic aspects of WtE change significantly between regions and countries, not only due to technical aspects but also depending on the waste treatment process implemented. The main costs of WtE plants are generally conditioned by the following factors: Scale (disadvantages for small scale operation); Costs of land acquisition; The actual requirements for the treatment of fluegases/effluents, (e.g. emission); Requirements by the local Authorities (usually environmental performances) and energy recovery efficiency (heat and power). The main process data are designed to provide both. Therefore, a particular technology has to be selected. Cost effects are: - the treatment and disposal/recovery of ashes residues are mainly conditioned by: i. the market; ii. the owners of these authorized plants; - the efficiency of energy recovery / benefits received for the energy delivered. The Business Plan has to clarify the trade-off between: iii. the cost to improve the technical choices; iv. the benefits derived by the energy market; The recovery of metals and the revenues received from this operation; Taxes or subsidies received for incineration and/or imposed on emissions - direct and indirect; Taxes and subsidies on waste at check point (gate fees), which range varies from 10% to 75% of the inlet waste price; the pay-back period may be highly influenced. Architectural requirements; the architectural type of the WtE plants mirrors the same architectural characteristics of the area: I. Parma: the WtE plant s architecture is a typical brick factory. II. Turin: the WtE plant s architecture has been designed by Gruppo Bertone, one of the best known company specialized in car styling founded in Turin; Development of the surrounding area for waste delivery access, and other infrastructures; Based on IREN experiences, WtE plants costs are divided into the following phases: engineering constructions, commissioning and start up, and lie in the ranges: thousand /t in the case of large plant size with capacities reaching 421,000 t/y as seen in the WtE plant in Turin s thousand /t in the case of small plant size such as Piacenza and Parma The cost are expressed in thousand /t of MSW inlet.

11 Page11 The European situation 2012). Currently, there is a huge gap in the WtE development in Europe, resulting in several EU countries already experiencing a hold in the expansion of the WtE due to a possible national overcapacity, while the majority of the EU countries still have under-capacities or no waste incineration at all. The result is a significant decrease in the overall investments into the WtE technology in Europe, since the investment into waste in the countries with most developed Waste Management seems to be slowing down (Malek, S. A report made by ISPRA (Istituto Superiore per la Protezione e la Ricerca Ambientale) considers the percentage subdivision of the principle waste management methods for each EU country (Eurostat data). The report underlines that almost 24% of the urban waste is incinerated. During the period , a stringent implementation of European waste management policies intended to reduce the utilization of landfill has influenced the trend of waste disposal methods. Figure 8: Percentage subdivision for MW methods in EU - 28 In 2012, among the European states, almost 57 million tons of waste has been treated by incineration. A percentage of 97.7% of these has been incinerated by the states composing EU 15. Compared to 2011, a reduction of 4.1% on the total amount of MSW treated by incineration is registered. Concerning the data on incineration, it is evident that a heterogeneous situation exists among the European states: almost 28.6 million tons are incinerated in Germany and France (equal to 50.2% of the MSW total amount), (3) whereas for example, 5 member states (Bulgaria, Grecia, Cipro, Lettonia and Romania) do not exploit incineration methods. The situation in kg per capita of MSW treated by incineration during in Europe is described in fig.8.the utilization of WtE method is most common in Denmark (349 kg/ inhabitants per year), Netherlands (270 kg/inhabitants per year) and Sweden (239 kg/inhabitants per year) (ISPRA, 2014).

12 Page12 Figure 9: MSW treated by incineration (in kg per capita) in EU - 28 (Eurostat, 2012) An expansion of WtE is also expected in Eastern Europe. The trend has been set by many announced plans for WtE implementations in the coming years. Since the region has no waste incineration plants, it could represent a big potential market in the next five years. According to the estimations of the Waste-to-Energy Research and Technology Council Germany (WtERT Germany), more than 50 WtE and Refuse-Derived- Fuel projects are in progress and/or planned in Eastern Europe. However the realization of planned capacities is still rather uncertain. Furthermore, some European countries have a policy which limits incineration. This can be related to the countries economic situation, which at the moment is not ready to guarantee a complete chain of waste treatment: separate collection systems, disposal for by-products. It is therefore fair to conclude that, in spite of overall insufficient WtE capacities in Europe, the development of the market is still facing many challenges. Main investing states in WtE are dealing with overcapacities, while the states with under-capacities attempt to deal with the public acceptance of the technology, the lack of a Waste Management strategy or the lack of investment potential. It is therefore difficult to estimate the growth of WtE market as well as its speed. The forecast regarding the expansion of WtE is mostly related to each national waste production trend. Taking into consideration all possible circumstances that can affect waste generation in the future, such estimation is full of uncertainties. References - Saša Malek (2012) Waste to Energy in Eastern and South Eastern Europe. Springer - ISPRA (Istituto Superiore per la Protezione e la Ricerca Ambientale) Rapporto rifiuti urbani Edizione 2014; - Eurostat (2012) Eurostat.ec.europa.eu: municipal waste generated and treated in (Online). Available from IPPC: Integrated Pollution Prevention and Control Waste incineration August 2006

13 Page13 Copyright UNDP/CEDRO The findings, interpretations and conclusions expressed in this report are those of the authors and do not necessarily represent those of the United Nations Development Programme (UNDP). The Consultant does not guarantee the accuracy of the data included in this report. The boundaries, colors, denominations, and other information shown on maps and images in this work do not imply any judgment on the part of the Consultant or UNDP concerning the legal status of any territory or the endorsement or acceptance of such boundaries. The United Nations Development Programme and the Consultant assume no responsibility of any kind for the use that may be made of the information contained in this report. info@cedro-undp.org

Waste to Energy WTERT, N.Y., October 2008

Waste to Energy WTERT, N.Y., October 2008 Waste to Energy MUNICIPAL SOLID WASTE INCINERATION WITH SIMULTANEOUS ENERGY PRODUCTION (WASTE TO ENERGY) MUNICIPAL SOLID WASTE TREATMENT IN THE SURROUNDINGS ATHENS REGION One of the most important political