Biofuel Production from Waste Wood - Product Life Cycle Assessment - Coursework Example

Biofuel production from waste wood - (Product Life Cycle Assessment (PLCA) Table of Contents Table of Contents 2 Chapter 3 Introduction 3 Aim and Objectives 3 Chapter 2: Literature Review 4 Life cycle assessment 4 Chapter 3: Methodology 5 Life Cycle Assessment of Wood Pellets process and Principles 5 Chapter 4 7 Results: Inventory Analysis 7 Impact Assessment and Interpretation 8 Chapter 5 10 Discussion 10 Chapter 6 10 Conclusion and Recommendation 10 Bibliography 12 Chapter 1 Introduction Wood pellets relate to a type of processed biomass fuel that offers various significant advantages over unprocessed biomass. For instance, wood pellets normally contain relatively low moisture content that contributes to its significance resistance to microbial degeneration. Moreover, wood pellets provide better combustion properties and higher energy density besides being a renewable source of energy and consequently having insignificant contribution to green house effect compared to fossil fuels. Furthermore, wood pellets remains as the cheapest source of energy compared to petroleum oil. However, wood pellets have drawbacks including requirement for large storage facilities and continuous removal and control of ashes (Chen, 2009, p 2). It is indispensable to comprehend that use of wood pellets as a substitute energy source to fossil fuels remains essential in significant reduction of global warming effects and minimal emissions of green gases. Aim and Objectives The report aims at understanding the life cycle of wood pellets and its contribution to environmental degradations. In addition, the report provides an assessment of wood pellets life cycle in relation to its human effects. Besides, the fundamental objective of the report is to assist wood pellets producers in communicating with customers. Moreover, the producers would also ensure better environmental management. Chapter 2: Literature Review Life cycle assessment Life cycle assessment (LCA) relates to an environmental evaluation device that focuses on analyzing environmental impacts associated with use of a process or product within its entire duration or life. The inherent assessment remains achievable through creation of a systematic model that can carry out quantification of energy and materials consumption and calculation of released wastes and emissions (Manyele, 2007, p 142). Such computation of effects occurs of life cycle of the process or product from raw materials extraction, production, transportation, reuse and use phases, and consequent recycling stage. Therefore, there exist four significant steps in performing LCA including last step called interpretation, life cycle impact assessment, inventory analysis, and the first step being goal and scope definition. Assessment of wood pellets life cycle is domineering in quantifying and analyzing its global warming potentials in comparison to fossil fuels. Moreover, the assessment remains vital in communicating with customers that constantly uses fuels and more importantly to investigate impacts of the energy on the environment. The diagram below illustrates the stages of wood pellets life cycle as aforementioned. It is imperative to note that interpretation is fundamental at every stage for comprehensive analysis and results. (Source: Stano, 2013) Chapter 3: Methodology Life Cycle Assessment of Wood Pellets process and Principles In initiating a comprehensive LCA of wood pellets, there must exist a vividly determined goal that states intended reasons and applications for conducting the assessment. Thereafter, the researcher can use the goals to determine scope of the study based on technological, temporal and geographical coverage. The intended application of the assessment relies on gaining a comprehension of the environmental issues in association with using wood pellets as source of fuel relative to other available sources of energy including fossil fuels. Assessment results would be imperative in communicating with future customers and facilitating better environmental management initiatives. Concerning functional unit, wood pellets remains indispensable in energy provision as either electricity or heat (Börjesson et al., 2010, p 2). In addition, the study would exist as accounting LCA with impact categories being human health, ecological consequences, and resource depletion (Chen, 2009, p 8). The next imperative step in assessment of wood pellets life cycle entails inventory analysis. Based on inventory analysis, the entire life cycle relating to wood pellet significantly have eight (8) processes. The eight processes starts from Silviculture and ends with waste management through wood transportation, sawmilling, raw materials transportation, and finally pellet production and distribution. Inventory analysis aims at gathering all the fundamental data that have relation to environmental impacts during use of wood pellets as source of energy. Generation of the aforementioned data must follow the requirements outlined within the goal and scope definition based on a system model of operation. The inventory results obtained from the aforementioned analysis is imperative in assessment of energy usage, emissions, and use of resources within each process of wood pellets life cycle. During inventory analysis that helps in evaluating environmental performance of the life cycles processes, the analytic tool uses collected inventory data in calculation of materials flow and energy. During calculation processes, the assessment examines functional units with consideration of system boundary. Calculations methods assist in establishing energy and material flow across the systems boundaries and life cycle processes. In generating energy and material flow for wood pellets life cycle, the assessment uses three fundamental calculation methods. The first method entails initial generation of mass balance followed by material flow across the systems boundary in reference to functional unit. The second step entails calculation of each system’s process energy. The last calculation method involves obtaining emissions systems related to each system and conversion of energy in all the processes. Establishing functional unit and mass balance of all the process and consequent material flows formulation is imperative in conducting life cycle inventory analysis. The most fundamental energy sources in life cycle of wood pellets include biofuels, electricity, and fossil fuels. During inventory analysis, the assessment accounts for emissions from each source of energy in all the processes. Chapter 4 Results: Inventory Analysis Based on the inventory results in relation to energy use, emissions, and use of resources for the entire life cycle of wood pellets, only three processes requires use of electricity. The processes include pellet combustion, production, and sawmill operations. Moreover, energy use indicates that Silviculture process acts as the most significant fossil fuel dependant. Intense energy use during pellet production results from significant steps within the pellet plant including pelleting, drying, and grinding of wood. It is indispensable to note that the aforementioned steps require consumption of large quantities of energy. Electricity acts as the highest source of energy consumed during pellet production mainly during ignition and automatic feeding pellet burners with wood pellets. Pellet production defines the most-energy intense process in the life cycle of wood pellets. Concerning emissions, the final combustion of wood pellets process results into the most air emissions throughout the entire life cycle. However, pellet production process has the highest hydrocarbon emissions mainly due to incomplete bio-fuel mass combustion. Pellet combustion process acts the largest contributor to emission of nitrogenous gases, carbon monoxide, methane, and phosphorous gases. The assessment indicates that emission of carbon dioxide originates from electricity production mainly because combustion of wood pellets does not result into release of the gas. In addition, during the entire life cycle of wood pellets, pellet production process contributes to the highest emission of hydrocarbons in comparison to other stages. The diagram below illustrates the stages involved in pellet production and subsequent storage. It is observable that there exists inherent consumption of fossil energy by the machines involved at every stage. The comprehensive stages involved define intense energy usage of pellet production process and its contribution to gas emissions. (Source: Wood Pellet Machines, 2011) Impact Assessment and Interpretation Impact assessment helps in determining impact category association to specific processes or products. Such assessments remains essential in broadening information obtained from inventory analysis. In impact assessment, the fundamental categories of consideration include ecological consequence, resource depletion, and human health. Based on inventory analysis of wood pellets each of the aforementioned impact categories has sub-sections that require assessment. For instance, ecological consequence has sections such as eutrophication, global warming, acidification, and photo-oxidant formation. On the contrary, human health contributes to toxicological impacts while resource depletion defines material and energy depletion. Impact assessments and interpretation analysis at characterization level indicates that there exists six potential environmental effects associated with wood pellets production. In summary as aforementioned, the environmental impacts include acidification, global warming, eutrophication, resource depletion, human toxicity and photochemical oxidant formation. The environmental impacts results from green house gas emissions such as sulfur gases, nitrogen oxides, carbon dioxide, depletion of fossil fuels and emission of methane. The inventory analysis results also indicate that silviculture acts as the largest contributor of carbon (IV) oxide due to the largest consumption of fossil fuels. Moreover, silviculture process contributes to the significant high emission of sulfur (IV) oxide. However, in relation to resource depletion, sawmill operations have the largest potential. High resource depletion potential of process results from use of fossil fuels and high demand of timber (Chen, 2009.p, 33). It is essential to understand that transportation process have insignificant contribution of environmental impacts within the entire life cycle of wood pellets. The diagram below explains the interplay of nature and carbon gases emitted during combustion of wood pellets. (Source: Green Gaya, 2015) Chapter 5 Discussion Pellet combustion acts as the largest contributor of human toxicity with photochemical oxidant and eutrophication potential. In consideration to global warming potentials, wood pellets have a variety of environmental advantages. The advantages include lower production of carbon dioxide, efficient combustion, and minimal release of particulate matter emissions. On the contrary, Silviculture process within the lifecycle of wood pellets acts as the main contributor of global warming. Moreover, it is imperative to note that depletion of fossil fuels acts as the most fundamental parameter according to valuation methods of wood pellets life cycle. Furthermore, the inventory analysis results of wood pellets indicates that the fossil fuels acts as the most fundamental contributor of carbon dioxide emission compared to emission free biofuel. Significant reduction of fossil fuels usage would be essential in improvement of wood pellets environmental performance. Chapter 6 Conclusion and Recommendation In conclusion, wood pellets production remains as the less complicated industrial process mainly due to its straightforwardness and simplicity. Moreover, the required raw materials including wood chips and sawdust that are sawn wood byproducts remain easily and inexpensively obtainable. Assessment results from inventory analysis indicate that the largest contributor of carbon (IV) oxide remains as Silviculture process. Highest emission of carbon (IV) oxide during Silviculture process results from extensive use fossil fuels by the machines involved in the stage. In addition, process of pellet combustion acts as the least-environmental friendly mainly due to its emissions to water and air. Incomplete combustion of biofuels contributes to the largest emission of hydrocarbons during pellet production and consequent extensive use of energy by the process. Wood pellets production and use remains as the most effective strategy of implementing and realizing green revolution and minimizing contribution to climate change. However, realization of significant results requires reduction of fossil fuel consumption during wood pellets production life cycle. Bibliography Börjesson, Pål, Tufvesson, Linda and Lantz, Mikael (2010). Life Cycle Assessment of Biofuels in Sweden. Lund, Sweden. Lund University. Chen, Siyu. (2009). Life Cycle Assessment of Wood Pellet. Master of Science Thesis in the Master Degree Program, Environmental Measurements and Assessment. Chalmers University of Technology. Göteborg, Sweden: Green Gaya. (January 16, 2015). Wood Pellet Sustainability. Web. January 24, 2015. Retrieved from http://www.greengaya.com/publication/wood-pellet-sustainability Manyele, S, V. (2007). Lifecycle assessment of biofuel production from wood pyrolysis technology. Education research and review Vol 2 (6) pp 141-150. Stano, Števo. (January 18, 2013). Zero House? Reality or fiction. Posterus. Sk. Web. January 24, 2015. Retrieved from http://www.posterus.sk/?p=14455&output=pdf Wood Pellet Machines. (July 27, 2011). The pellet making process. Web. January 24, 2015. Retrieved from http://www.wood-pellet-machines.com/the-pellet-making-process.html Read More