Quality assurance of refuse derived fuel with machine vision

This thesis studies the use of machine vision in RDF quality assurance and manufacturing. Currently machine vision is used in recycling and material detection and some commer- cial products are available in the market. In this thesis an on-line machine vision system is proposed for characterizing particle size. The proposed machine vision system is based on the mapping between image segmenta- tion and the ground truth of the particle size. The results shows that the implementation of such machine vision system is feasible.

Assessment of bacteria and virus emissions at a refuse derived fuel plant and other waste handling facilities /

Mode of access: Internet.

Viability study of automobile shredder residue as fuel

Car Fluff samples collected from a shredding plant in Italy were classified based on particle size, and three different size fractions were obtained in this way. A comparison between these size fractions and the original light fluff was made from two different points of view: (i) the properties of each size fraction as a fuel were evaluated and (ii) the pollutants evolved when each size fraction was subjected to combustion were studied. The aim was to establish which size fraction would be the most suitable for the purposes of energy recovery. The light fluff analyzed contained up to 50 wt.% fines (particle size < 20 mm). However, its low calorific value and high emissions of polychlorinated dioxins and furans (PCDD/Fs), generated during combustion, make the fines fraction inappropriate for energy recovery, and therefore, landfilling would be the best option. The 50–100 mm fraction exhibited a high calorific value and low PCDD/F emissions were generated when the sample was combusted, making it the most suitable fraction for use as refuse-derived fuel (RDF). Results obtained suggest that removing fines from the original ASR sample would lead to a material product that is more suitable for use as RDF.

European refuse-fired energy systems : evaluation of design practices /

Mode of access: Internet.

San Diego County demonstrates pyrolysis of solid waste : to recover liquid fuel, metals, and glass /

Grant No. S-801588.

Municipal solid waste management system: decision support through systems analysis

Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia for the degree of Doctor of Philosophy in Environmental Engineering

Formation and Control of Trace Metal Emissions in Co-Firing of Biomass, Peat, and Wastes in Fluidised Bed Combustors

Environmentally harmful consequences of fossil fuel utilisation andthe landfilling of wastes have increased the interest among the energy producers to consider the use of alternative fuels like wood fuels and Refuse-Derived Fuels, RDFs. The fluidised bed technology that allows the flexible use of a variety of different fuels is commonly used at small- and medium-sized power plants ofmunicipalities and industry in Finland. Since there is only one mass-burn plantcurrently in operation in the country and no intention to build new ones, the co-firing of pre-processed wastes in fluidised bed boilers has become the most generally applied waste-to-energy concept in Finland. The recently validated EU Directive on Incineration of Wastes aims to mitigate environmentally harmful pollutants of waste incineration and co-incineration of wastes with conventional fuels. Apart from gaseous flue gas pollutants and dust, the emissions of toxic tracemetals are limited. The implementation of the Directive's restrictions in the Finnish legislation is assumed to limit the co-firing of waste fuels, due to the insufficient reduction of the regulated air pollutants in the existing flue gas cleaning devices. Trace metals emission formation and reduction in the ESP, the condensing wet scrubber, the fabric filter, and the humidification reactor were studied, experimentally, in full- and pilot-scale combustors utilising the bubbling fluidised bed technology, and, theoretically, by means of reactor model calculations. The core of the model is a thermodynamic equilibrium analysis. The experiments were carried out with wood chips, sawdust, and peat, and their refuse-derived fuel, RDF, blends. In all, ten different fuels or fuel blends were tested. Relatively high concentrations of trace metals in RDFs compared to the concentrations of these metals in wood fuels increased the trace metal concentrations in the flue gas after the boiler ten- to hundred-folds, when RDF was co-fired with sawdust in a full-scale BFB boiler. In the case of peat, lesser increase in trace metal concentrations was observed, due to the higher initial trace metal concentrations of peat compared to sawdust. Despite the high removal rate of most of the trace metals in the ESP, the Directive emission limits for trace metals were exceeded in each of the RDF co-firing tests. The dominat trace metals in fluegas after the ESP were Cu, Pb and Mn. In the condensing wet scrubber, the flue gas trace metal emissions were reduced below the Directive emission limits, whenRDF pellet was used as a co-firing fuel together with sawdust and peat. High chlorine content of the RDFs enhanced the mercuric chloride formation and hence the mercury removal in the ESP and scrubber. Mercury emissions were lower than theDirective emission limit for total Hg, 0.05 mg/Nm3, in all full-scale co-firingtests already in the flue gas after the ESP. The pilot-scale experiments with aBFB combustor equipped with a fabric filter revealed that the fabric filter alone is able to reduce the trace metal concentrations, including mercury, in the flue gas during the RDF co-firing approximately to the same level as they are during the wood chip firing. Lower trace metal emissions than the Directive limits were easily reached even with a 40% thermal share of RDF co-firing with sawdust.Enrichment of trace metals in the submicron fly ash particle fraction because of RDF co-firing was not observed in the test runs where sawdust was used as the main fuel. The combustion of RDF pellets with peat caused an enrichment of As, Cd, Co, Pb, Sb, and V in the submicron particle mode. Accumulation and release oftrace metals in the bed material was examined by means of a bed material analysis, mass balance calculations and a reactor model. Lead, zinc and copper were found to have a tendency to be accumulated in the bed material but also to have a tendency to be released from the bed material into the combustion gases, if the combustion conditions were changed. The concentration of the trace metal in the combustion gases of the bubbling fluidised bed boiler was found to be a summary of trace metal fluxes from three main sources. They were (1) the trace metal flux from the burning fuel particle (2) the trace metal flux from the ash in the bed, and (3) the trace metal flux from the active alkali metal layer on the sand (and ash) particles in the bed. The amount of chlorine in the system, the combustion temperature, the fuel ash composition and the saturation state of the bed material in regard to trace metals were discovered to be key factors affecting therelease process. During the co-firing of waste fuels with variable amounts of e.g. ash and chlorine, it is extremely important to consider the possible ongoingaccumulation and/or release of the trace metals in the bed, when determining the flue gas trace metal emissions. If the state of the combustion process in regard to trace metals accumulation and/or release in the bed material is not known,it may happen that emissions from the bed material rather than the combustion of the fuel in question are measured and reported.

Jätteenpolttolaitosten nykytilasta ja tulevaisuuden näkymistä viidessä Euroopan maassa

Tutkimuksen tavoitteena oli kartoittaa jätteenpolttolaitosten nykytilannetta ja tulevaisuuden näkymiä aina vuoteen 2015 asti viidessä Euroopan maassa (Saksa, Ranska, Iso-Britannia, Espanja ja Italia). Jätteenpoltolla ja jätteenpolttolaitoksella käsitettiin tässä tutkimuksessa kaikki jätteenpolttodirektiivin 2000/76/EY alaisuuteen kuuluva jätteen polttaminen. Tutkimus oli luonteeltaan kvalitatiivista eli laadullista. Tutkimusmenetelmänä käytettiin asiantuntijahaastatteluita. Asiantuntijat olivat useista Euroopan maista ja edustivat eri organisaatioita. Haastattelut toteutettiin puhelimen ja sähköpostin välityksellä. Tutkimuksen johtopäätöksenä oli, että jätteenpoltto on kasvava ala kaikissa tutkimuksen kohdemaissa ja että uusia jätteenpolttolaitoksia tullaan rakentamaan kaikkiin viiteen maahan. Eräänä tärkeimmistä syistä oli ns. kaatopaikkadirektiivin 1999/31/EY asettamat rajoitukset kaatopaikoille vietävän jätteen määrälle. Jätteiden rinnakkaispoltto ja jätteistä jalostettujen polttoaineiden käyttö tunnistettiin tulevaisuuden kannalta merkittäviksi trendeiksi.

Kierrätyspolttoainemarkkinat Euroopassa

Työn tavoitteena oli selvittää Saksan, Ruotsin ja Suomen kierrätyspolttoaineen valmistusta ja käyttöä sekä kierrätyspolttoainemarkkinoita. Kierrätyspolttoaineiden käyttöä ja valmistusta sekä kierrätyspolttoainemarkkinoita säädellään tarkastelumaissa EU-lainsäädännöllä ja kansallisilla lainsäädännöillä jätteistä, jätteenpoltosta ja materiaalikierrätyksestä sekä CEN/TC 343-toimikunnan standardeilla kiinteille kierrätyspolttoaineille. Työn johtopäätöksenä on, että kierrätyspolttoainemarkkinat ovat tarkastelumaissa hyvin ulkoapäin ohjautuvat ja markkinaehtoista tasapainoa ei ehdi syntyä. Tarkastelumaiden markkinat ovat erilaiset, Saksassa kierrätyspolttoaineiden käyttö ja valmistus on pitkälle kehittynyttä, tiheää ja monipuolista, Ruotsissa yhteisen termistön puuttuminen kertoo alan hajanaisuudesta. Saksassa ja Ruotsissa kierrätyspolttoainemarkkinoiden kasvamiseen ovat vaikuttaneet kaatopaikkakiellot. Suomessa tähän asti pelkkään rinnakkaispolttoon perustuneet kierrätyspolttoainemarkkinat ovat vasta vakiintumassa. Kierrätyspolttoainemarkkinat tulevat kansainvälistymään ja kilpailu materiaalista tulee kovenemaan. Standardien käyttöönotto tulee olemaan helpointa Suomessa, jossa kierrätyspolttoaineen standardisoinnista on kokemusta. Suomen olisi syytä ottaa jäte- ja energiahuollon ratkaisuissa huomioon eri toimintojen aiheuttamat talous- ja ympäristövaikutukset.

Current status of the waste-to-energy chain in the County of North Savo, Finland

The aim of this report is to describe the current status of the waste-to-energy chain in the province of Northern Savonia in Finland. This work is part of the Baltic Sea Region Programme project Remowe-Regional Mobilizing of Sustainable Waste-to-Energy Production (2009-2012). Partnering regions across Baltic Sea countries have parallelly investigated the current status, bottle-necks and needs for development in their regions. Information about the current status is crucial for the further work within the Remowe project, e.g. in investigating the possible future status in target regions. Ultimate result from the Northern Savonia point of view will be a regional model which utilizes all available information and facilitates decision-making concerning energy utilization of waste. The report contains information on among others: - waste management system (sources, amounts, infrastructure) - energy system (use, supply, infrastructure) - administrative structure and legislation - actors and stakeholders in the waste-to-energy field, including interest and development ideas The current status of the regions will be compared in a separate Remowe report, with the focus on finding best practices that could be transferred among the regions. In this report, the current status has been defined as 2006-2009. In 2009, the municipal waste amount per capita was 479 kg/inhabitant in Finland. Industrial waste amounted 3550 kg/inhabitant, respectively. The potential bioenergy from biodegradable waste amounts 1 MWh/inhabitant in Northern Savonia. This figure includes animal manure, crops that would be suitable for energy use, sludge from municipal sewage treatment plants and separately collected biowaste. A key strategy influencing also to Remowe work is the waste plan for Eastern Finland. Currently there operate two digestion plants in Northern Savonia: Lehtoniemi municipal sewage treatment sludge digestion plant of Kuopion Vesi and the farm-scale research biogas plant of Agrifood Research Finland in Maaninka. Moreover, landfill gas is collected to energy use from Heinälamminrinne waste management centre and Silmäsuo closed landfill site, both belonging to Jätekukko Oy. Currently there is no thermal utilization of waste in Northern Savonia region. However, Jätekukko Oy is pretreating mixed waste and delivering refuse derived fuel (RDF) to Southern Finland to combustion. There is a strong willingness among seven regional waste management companies in Eastern Finland to build a waste incineration plant to Riikinneva waste management centre near city of Varkaus. The plant would use circulating fluidized bed (CFB) boiler. This would been a clear boost in waste-to-energy utilization in Northern Savonia and in many surrounding regions.

Characterisation of waste for combustion : with special reference to the role of zinc

Waste combustion has gone from being a volume reducing discarding-method to an energy recovery process for unwanted material that cannot be reused or recycled. Different fractions of waste are used as fuel today, such as; municipal solid waste, refuse derived fuel, and solid recovered fuel. Furthermore, industrial waste, normally a mixture between commercial waste and building and demolition waste, is common, either as separate fuels or mixed with, for example, municipal solid waste. Compared to fossil or biomass fuels, waste mixtures are extremely heterogeneous, making it a complicated fuel. Differences in calorific values, ash content, moisture content, and changing levels of elements, such as Cl and alkali metals, are common in waste fuel. Moreover, waste contains much higher levels of troublesome trace elements, such as Zn, which is thought to accelerate a corrosion process. Varying fuel quality can be strenuous on the boiler system and may cause fouling and corrosion of heat exchanger surfaces. This thesis examines waste fuels and waste combustion from different angles, with the objective of giving a better understanding of waste as an important fuel in today’s fuel economy. Several chemical characterisation campaigns of waste fuels over longer time periods (10-12 months) was used to determine the fossil content of Swedish waste fuels, to investigate possible seasonal variations, and to study the presence of Zn in waste. Data from the characterisation campaigns were used for thermodynamic equilibrium calculations to follow trends and determine the effect of changing concentrations of various elements. The thesis also includes a study of the thermal behaviour of Zn and a full—scale study of how the bed temperature affects the volatilisation of alkali metals and Zn from the fuel. As mixed waste fuel contains considerable amounts of fresh biomass, such as wood, food waste, paper etc. it would be wrong to classify it as a fossil fuel. When Sweden introduced waste combustion as a part of the European Union emission trading system in the beginning of 2013 there was a need for combustion plants to find a usable and reliable method to determine the fossil content. Four different methods were studied in full-scale of seven combustion plants; 14Canalysis of solid waste, 14C-analysis of flue gas, sorting analysis followed by calculations, and a patented balance method that is using a software program to calculate the fossil content based on parameters from the plant. The study showed that approximately one third of the coal in Swedish waste mixtures has fossil origins and presented the plants with information about the four different methods and their advantages and disadvantages. Characterisation campaigns also showed that industrial waste contain higher levels of trace elements, such as Zn. The content of Zn in Swedish waste fuels was determined to be approximately 800 mg kg-1 on average, based on 42 samples of solid waste from seven different plants with varying mixtures between municipal solid waste and industrial waste. A review study of the occurrence of Zn in fuels confirmed that the highest amounts of Zn are present in waste fuels rather than in fossil or biomass fuels. In tires, Zn is used as a vulcanizing agent and can reach concentration values of 9600-16800 mg kg-1. Waste Electrical and Electronic Equipment is the second Zn-richest fuel and even though on average Zn content is around 4000 mg kg-1, the values of over 19000 mg kg-1 were also reported. The increased amounts of Zn, 3000-4000 mg kg-1, are also found in municipal solid waste, sludge with over 2000 mg kg-1 on average (some exceptions up to 49000 mg kg-1), and other waste derived fuels (over 1000 mg kg-1). Zn is also found in fossil fuels. In coal, the average level of Zn is 100 mg kg-1, the higher amount of Zn was only reported for oil shale with values between 20-2680 mg kg-1. The content of Zn in biomass is basically determined by its natural occurrence and it is typically 10-100 mg kg-1. The thermal behaviour of Zn is of importance to understand the possible reactions taking place in the boiler. By using thermal analysis three common Zn-compounds were studied (ZnCl2, ZnSO4, and ZnO) and compared to phase diagrams produced with thermodynamic equilibrium calculations. The results of the study suggest that ZnCl2(s/l) cannot exist readily in the boiler due to its volatility at high temperatures and its conversion to ZnO in oxidising conditions. Also, ZnSO4 decomposes around 680°C, while ZnO is relatively stable in the temperature range prevailing in the boiler. Furthermore, by exposing ZnO to HCl in a hot environment (240-330°C) it was shown that chlorination of ZnO with HCl gas is possible. Waste fuel containing high levels of elements known to be corrosive, for example, Na and K in combination with Cl, and also significant amounts of trace elements, such as Zn, are demanding on the whole boiler system. A full-scale study of how the volatilisation of Na, K, and Zn is affected by the bed temperature in a fluidised bed boiler was performed parallel with a lab-scale study with the same conditions. The study showed that the fouling rate on deposit probes were decreased by 20 % when the bed temperature was decreased from 870°C to below 720°C. In addition, the lab-scale experiments clearly indicated that the amount of alkali metals and Zn volatilised depends on the reactor temperature.

Small modular incinerator systems with heat recovery : a technical, environmental, and economic evaluation /

November 1979.

Markets and technology for recovering energy from solid waste /

Bibliography: p. 30-31.

Baltimore demonstrates gas pyrolysis : resource recovery from solid waste /

Mode of access: Internet.