The feasibility of torrefaction for the co-firing of wood in pulverised-fuel boilers

Torrefaction is the partial pyrolysis of wood characterised by thermal degradation of predominantly hemicellulose under inert atmosphere. Torrefaction can be likened to coffee roasting but with wood in place of beans. This relatively new process concept makes wood more like coal. Torrefaction has attracted interest because it potentially enables higher rates of co-firing in existing pulverised-coal power plants and hence greater net CO2 emission reductions. Academic and entrepreneurial interest in torrefaction has sky rocketed in the last decade. Research output has focused on the many aspects of torrefaction – from detailed chemical changes in feedstock to globally-optimised production and supply scenarios with which to sustain EU emission-cutting directives. However, despite its seemingly simple concept, torrefaction has retained a somewhat mysterious standing. Why hasn’t torrefied pellet production become fully commercialised? The question is one of feasibility. This thesis addresses this question. Herein, the feasibility of torrefaction in co-firing applications is approached from three directions. Firstly, the natural limitations imposed by the structure of wood are assessed. Secondly, the environmental impact of production and use of torrefied fuel is evaluated and thirdly, economic feasibility is assessed based on the state of the art of pellet making. The conclusions reached in these domains are as follows. Modification of wood’s chemical structure is limited by its naturally existing constituents. Consequently, key properties of wood with regards to its potential as a co-firing fuel have a finite range. The most ideal benefits gained from wood torrefaction cannot all be realised simultaneously in a single process or product. Although torrefaction at elevated pressure may enhance some properties of torrefied wood, high-energy torrefaction yields are achieved at the expense of other key properties such as heating value, grindability, equilibrium moisture content and the ability to pelletise torrefied wood. Moreover, pelletisation of even moderately torrefied fuels is challenging and achieving a standard level of pellet durability, as required by international standards, is not trivial. Despite a reduced moisture content, brief exposure of torrefied pellets to water from rainfall or emersion results in a high level of moisture retention. Based on the above findings, torrefied pellets are an optimised product. Assessment of energy and CO2-equivalent emission balance indicates that there is no environmental barrier to production and use of torrefied pellets in co-firing. A long product transport distance, however, is necessary in order for emission benefits to exceed those of conventional pellets. Substantial CO2 emission reductions appear possible with this fuel if laboratory milling results carry over to industrial scales for direct co-firing. From demonstrated state-of-the-art pellet properties, however, the economic feasibility of torrefied pellet production falls short of conventional pellets primarily due to the larger capital investment required for production. If the capital investment for torrefied pellet production can be reduced significantly or if the pellet-making issues can be resolved, the two production processes could be economically comparable. In this scenario, however, transatlantic shipping distances and a dry fuel are likely necessary for production to be viable. Based on demonstrated pellet properties to date, environmental aspects and production economics, it is concluded that torrefied pellets do not warrant investment at this time. However, from the presented results, the course of future research in this field is clear.

Ympäristöjohtaminen tienrakennushankkeessa

Tässä diplomityössä tutkittiin tienrakentamisen aikaista ympäristöjohtamista. Työn tavoitteena oli arvioida jo toteutuneen infrastruktuuriprojektin rakentamisen aikaisen ympäristöjohtamisen onnistumista, verrata toteutunutta ympäristöjohtamista standardiin SFS-EN ISO 14001 ja löytää standardin avulla kehitysehdotukset vastaavanlaisten projektien toteuttamisen aikaiseen ympäristöjohtamiseen tulevaisuudessa. Työ toteutettiin tutkimalla esimerkkiprojektin ympäristönsuojelulle ja ympäristövaikutusten seurannalle tehtyjä suunnitelmia, projektin rakentamisen aikana koottua laatuaineistoa, projektin aikana pidettyjä kokouksia ja tiedotustilaisuuksia sekä haastattelemalla projektin ympäristöjohtamisen toteutuksen kannalta avainhenkilöitä. Tutkimuksessa havaittiin, että jos projektijohto hyödyntäisi ISO 14001 standardia ym-päristöjohtamisensa perustana vastaavanlaisissa tienrakennusprojekteissa, pystyisi se kehittämään projektin urakoitsijoiden hankintavaihetta, projektin aikaista sisäistä ja ulkoista viestintää sekä projektinjohdon toteuttamaa laadunvalvontaa projektin aikana. ISO 14001 standardin hyödyntäminen projektin toteuttamisen aikaisessa ympäristöjoh-tamisessa vaatisi projektin ylimmän johdon sitoutumista standardin noudattamiseen. Ympäristöjohtaminen tulee implementoida osaksi projektijohtamista ja sen toimijoilla tulee olla konkreettista vaikutusvaltaa projektin toimintaan. Projektijohdon sitoutuminen standardin mukaisuuteen antaa puitteet ja käytännöt sekä vaatia että valvoa projektin toimijoiden ympäristönsuojelun toteutumista, raportointia ja viestintää.

Ekologisuuden merkitys julkisissa hankinnoissa

Ilmastonmuutos, ympäristön saastuminen sekä luonnonvarojen ehtyminen lukeutuvat voimakkaimpiin taustalla vaikuttaviin tekijöihin, joiden vuoksi ympäristönäkökohdat ovat nousseet yhä voimakkaammin esille julkisissa hankinnoissa. Julkisten hankintojen tekijät ovat velvoitettuja huomioimaan talouden ohella myös ympäristönäkökohdat. Suuren ostovolyyminsa vuoksi julkinen sektori voi toimia suunnannäyttäjänä ympäristöä säästävien hankintojen toteuttajana. Tämä Pro gradu –tutkielma kartoittaa ekologisten hankintojen merkitystä suomalaisissa kunnissa vuonna 2016. Tavoitteena on selvittää mitä julkisten hankintojen ekologisuus kunnille merkitsee, miten ekologisuus näkyy hankintaprosessissa sekä mitkä tekijät ovat ekologisten hankintojen esteenä ja mitkä tekijät puolestaan kannustavat kuntia tekemään ekologisia hankintoja. Tutkimuksen tuloksena selvisi, että kunnat suhtautuvat ekologisuuteen hankinnoissa varsin positiivisesti ja ennen kaikkea ympäristönäkökohdat koetaan tärkeänä osana hankintoja. Ympäristönäkökohtien huomioiminen hankintaprosessissa koetaan kuitenkin melko vaikeaksi. Erityisesti tiedon puute, hinta ja taloudelliset resurssit vaikeuttavat ekologisten hankintojen toteutusta. Positiivisesti ympäristönäkökohtien huomioimiseen hankinnoissa puolestaan vaikuttavat henkilöstön osaaminen, taloudellisuus ja lainsäädäntö.

Spatiotemporal Aspects of Environmental Monitoring in the Complex Coastal Region of Southwest Finland

The management and conservation of coastal waters in the Baltic is challenged by a number of complex environmental problems, including eutrophication and habitat degradation. Demands for a more holistic, integrated and adaptive framework of ecosystem-based management emphasize the importance of appropriate information on the status and changes of the aquatic ecosystems. The thesis focuses on the spatiotemporal aspects of environmental monitoring in the extensive and geomorphologically complex coastal region of SW Finland, where the acquisition of spatially and temporally representative monitoring data is inherently challenging. Furthermore, the region is subject to multiple human interests and uses. A holistic geographical approach is emphasized, as it is ultimately the physical conditions that set the frame for any human activity. Characteristics of the coastal environment were examined using water quality data from the database of the Finnish environmental administration and Landsat TM/ETM+ images. A basic feature of the complex aquatic environment in the Archipelago Sea is its high spatial and temporal variability; this foregrounds the importance of geographical information as a basis of environmental assessments. While evidence of a consistent water turbidity pattern was observed, the coastal hydrodynamic realm is also characterized by high spatial and temporal variability. It is therefore also crucial to consider the spatial and temporal representativeness of field monitoring data. Remote sensing may facilitate evaluation of hydrodynamic conditions in the coastal region and the spatial extrapolation of in situ data despite their restrictions. Additionally, remotely sensed images can be used in the mapping of many of those coastal habitats that need to be considered in environmental management. With regard to surface water monitoring, only a small fraction of the currently available data stored in the Hertta-PIVET register can be used effectively in scientific studies and environmental assessments. Long-term consistent data collection from established sampling stations should be emphasized but research-type seasonal assessments producing abundant data should also be encouraged. Thus a more comprehensive coordination of field work efforts is called for. The integration of remote sensing and various field measurement techniques would be especially useful in the complex coastal waters. The integration and development of monitoring system in Finnish coastal areas also requires further scientific assesement of monitoring practices. A holistic approach to the gathering and management of environmental monitoring data could be a cost-effective way of serving a multitude of information needs, and would fit the holistic, ecosystem-based management regimes that are currently being strongly promoted in Europe.

Assessing the Environmental Value of Water Treatment Solutions in the Mining Industry

Environmental accountability has become a major source of competitive advantage for industrial companies, because customers consider it as relevant buying criterion. However, in order to leverage their environmental responsibility, industrial suppliers have to be able to demonstrate the environmental value of their products and services, which is also the aim of Kemira, a global water chemistry company considered in this study. The aim of this thesis is to develop a tool which Kemira can use to assess the environmental value of their solutions for the customer companies in mining industry. This study answers to questions on what kinds of methods to assess environmental impacts exist, and what kind of tool could be used to assess the environmental value of Kemira’s water treatment solutions. The environmental impacts of mining activities vary greatly between different mines. Generally the major impacts include the water related issues and wastes. Energy consumption is also a significant environmental aspect. Water related issues include water consumption and impacts in water quality. There are several methods to assess environmental impacts, for example life cycle assessment, eco-efficiency tools, footprint calculations and process simulation. In addition the corresponding financial value may be estimated utilizing monetary assessment methods. Some of the industrial companies considered in the analysis of industry best practices use environmental and sustainability assessments. Based on the theoretical research and conducted interviews, an Excel based tool utilizing reference data on previous customer cases and customer specific test results was considered to be most suitable to assess the environmental value of Kemira’s solutions. The tool can be used to demonstrate the functionality of Kemira’s solutions in customers’ processes, their impacts in other process parameters and their environmental and financial aspects. In the future, the tool may be applied to fit also Kemira’s other segments, not only mining industry.