This publication focuses on the health and safety issues of the supply chain of solid Health and Safety Aspects biofuels with the objective to highlight commonly used mitigation methodologies of Solid Biomass Storage, to promote a better working environment when dealing with solid biofuels. It has been compiled as a joint effort by experts active in Transportation and Feeding Tasks 32, 36, 37 and 40 of the IEA Bioenergy Agreement, with their own specifi c fi elds of expertise. Only through this cooperation, it was possible to touch upon the full range of issues in one publication that one may come across when developing projects in which solid biomass fuels are produced, traded or used. The properties of a biomass material and the intended use determine how the material should be safely transported and stored. Self- heating, off-gassing and dust explosions are signifi cant challenges for the industry that have already resulted in signifi cant losses of capital investments and even tragic loss of life. Likewise, exposure to biologically active material, such as moulds and spores may form a serious hazard for the health of workers involved. With the growth of the bioenergy sector, it is important not only that opportunities for bioenergy are implemented in an effi cient and economic manner, but also safely. Produced by IEA Bioenergy Task 32, 36, 37 and 40 May 2013 I HEALTH AND SAFETY ASPECTS OF SOLID BIOMASS STORAGE, TRANSPORTATION AND FEEDING Report prepared by Jaap Koppejan, Procede Biomass BV, The Netherlands Anders Lönnermark, SP Technical Research Institute of Sweden Henry Persson, SP Technical Research Institute of Sweden Ida Larsson, SP Technical Research Institute of Sweden Per Blomqvist, SP Technical Research Institute of Sweden Mehrdad Arshadi, Swedish University of Agricultural Sciences Elizabeth Valencia-Reyes, Swedish University of Agricultural Sciences Staffan Melin, University of British Columbia Pat Howes, AEA Group, UK Patrick Wheeler, Lend Lease, UK David Baxter, Joint Research Institute, European Commission Lars Nikolaisen, Danish Technological Institute, Denmark On behalf of May 2013 Disclaimer: Whilst the information in this publication is derived from reliable sources an reasonable care has been taken in the compilation, IEA Bioenergy, its Tasks, and the authors of the publication cannot make any representation of warranty, expressed or implied, regarding the verity, accuracy, adequacy or completeness of the information contained herein. IEA Bioenergy, Task 32 and the authors do not accept any liability towards the readers and users of the publication for any inaccuracy, error, or omission, regardless of the cause, or any damages resulting therefrom. In no event shall IEA Bioenergy, Task32 or the authors have any liability for loss of profi ts and/or indirect, special, punitive or consequential damages. II PREFACE The rapid increase in the production and use of various types of biomass as energy carrier also leads to an increase in handling and storage activities throughout the supply chain. Biomass is a broad description of many materials with different chemical composition, moisture content and physical characteristics, each requiring special attention in order to comply with safety and health regulations. Some types of biomass used today such as wood pellets) are commercialized as biofuel commodities traded around the globe, while others are under-going intense research to explore the potential for commercial use. The properties of a biomass material and the intended use determine how the material should be safely transported and stored. Self-heating, off-gassing and dust explosions are signifi cant challenges for the industry that have already resulted in signifi cant losses of capital investments and even tragic loss of life. Likewise, exposure to biologically active material, such as moulds and spores may form a serious hazard for the health of workers involved. With the growth of the bioenergy sector, it is important not only that opportunities for bioenergy are implemented in an effi cient and economic manner, but also safely. IEA Bioenergy recognises the importance of safe production, trade and utilisation of a growing amount of biomass fuels. This publication focuses on the health and safety issues of the supply chain of solid biofuels with the objective to highlight commonly used mitigation methodologies to promote a better working environment when dealing with solid biofuels. It has been compiled as a joint effort by experts active in four different Tasks within the IEA Bioenergy Agreement, with their own specifi c fi elds of expertise. Only through this cooperation, it was possible to touch upon the full range of issues in one publication that one may come across when developing projects in which solid biomass fuels are produced, traded or used. Although this publication does provide the reader with signifi cant understanding of the relevant safety issue as well as several guidelines for handling, storage and transportation, it is important to realize that differences in material also lead to differences in risks and needs for safety measures, and every individual situation needs to be carefully assessed. The topic also remains important as new biofuels enter the market. Jaap Koppejan Task leader, IEA Bioenergy Task 32: Biomass Combustion and Cofi ring III EXECUTIVE SUMMARY With the continuous growth in production and utilisation the storage at several different locations in the fuel bulk. of solid biofuels, an increasing number of incidents For detection of any activity of the bulk, CO concentration have taken place related to the handling of the biofuels, should be measured in the air above the pellet surface. resulting in affected personnel due to injuries, infections, The fi rst sign of an on-going self-heating process is often intoxications etc. resulting in illness or tragic loss of a sticky and irritating smell (probably from aldehydes life, or severe material damage due to dust explosions, and low molecular carboxylic acids). If this is sensed, fi res etc. This report has been written by various experts there is already pyrolysis taking place somewhere in the that are active in the IEA Bioenergy agreement, to fuel bulk and a fi re fi ghting operation has to be initiated. provide the reader with an understanding of the causes, Such fi re fi ghting strategy needs to be determined case by effects and mitigation measures overview of the issues. case and requires specialised fi re fi ghting equipment and trained staff. Water should not be used in case of wood The properties of a biomass material and the intended use pellets, due to rapid expansion of the pellets (hindering determine how the material should be safely produced, the extinguishing operation and subsequent unloading of transported, stored and used. While woody biofuels such the silo) and the formation of explosive H2 through water as pellets and chips from fresh or recycled wood dominate gas shift reactions. A silo fi re is usually extinguished the market in terms of volumes, other solid biofuels by inerting the closed silo from the bottom, after which such as straw, biodegradable fuels used for anaerobic fuel is discharged from an opening in the silo wall. digestion and municipal solid waste pose specifi c health and safety challenges that need to be addressed. Off-gassing is the process where volatile organic compounds are released in the logistical chain. One Self-heating processes may be due to biological metabolic mechanism is the initial release of lipophilic compounds, reactions (microbiological growth), exothermic chemical yielding carbonyl compounds (aldehydes and ketones) reactions (chemical oxidation) and heat-producing and also complex terpenes. CO, CO2 and CH4 may also physical processes (e.g. moisture absorption), and it be released. The concentrations of aldehydes found in may occur both for dry and wet biofuels. It may become domestic sites and warehouses constitute a health hazard problematic if a pile or silo is so large that the heat and require attention and preventative measures to be generated cannot be easily dissipated to the surroundings. taken. Hexanal may enter the body by contact with skin While this is not the case for relatively small scale or by inhalation and cause skin irritation, headaches, and installations as e.g. used by households, it needs attention discomfort on the eyes and nose. Other aldehydes such as for larger industrial storages. Several test methods are methanal and ethanal are suspected to be carcinogenic available for determining self-heating potential and self- in high doses and may also have some short time effect ignition of materials on small scale, which can then be on human health. There are several guidelines issued by extrapolated to predict self-heating potential at larger government offi cial institutes that describe the effect scale. Apart from self-heating, biomass stock may be these aldehydes have on human health depending on set on fi re through various external sources such as hot exposure time and level. Monoterpenes (particularly bearings, overheated electric motors, back-fi re, etc. present in fresh raw material) cause eyes and respiratory system irritation. CO may be released from the auto Several conclusions can be drawn from the full scale silo oxidation of lipophilic compounds. Related hazards are fi res that have already taken place. The most important predominantly poisoning, but it may also contribute to prevention measure to take is temperature monitoring of self heating or ignition processes. A combination of proper IV ventilation, gas meters and the use of self-contained natural bodily response and the degree of variation in breathing devices is needed in areas where the levels individual sensitivity makes the determination of dose of CO might increase to poisonous concentrations. response relationships particularly diffi cult. Without this level of understanding it is diffi cult to ascribe defi nite Dust clouds are a major cause of damage in the limits and regulations that are “safe” for the population bioenergy sector.