Characterization and Life Cycle Exergo-Environmental Analysis of Wood Pellet Biofuel Produced in Khyber Pakhtunkhwa, Pakistan

Abstract

Major objectives of this study were to produce low-emitting wood pellet biofuel from selected agro-forest tree species, i.e., Kikar (Acacia nilotica), Oak (Quercus semicarpifolia), and Mesquite (Prosopis juliflora), grown in the southern part of the Khyber Pakhtunkhwa (KP) province of Pakistan using indigenously developed technology (pelletizer machine). Primary raw material, such as sawdust of the selected agro-forest tree species, was obtained from sawmills located in southern part of KP. Life cycle inventory (LCI) was sourced for entire production chain of the wood pellet biofuel by measuring quantities of various inputs consumed and output produced. In addition, the wood pellets were characterized to examine diameter, length, moisture content, ash content, bulk density, high heating value (HHV), low heating value (LHV), as well as nitrogen and sulphur contents. A comprehensive life cycle assessment was performed for wood pellet biofuel production chain using SimaPro v9.1 software. A functional unit of one (01) kilogram (kg) wood pellet biofuel was applied following a gate-to-gate approach. The results of the present study were in accordance with the recommended Italian standard CTI-R except for pellet bulk density and nitrogen content. The bulk density for all wood pellets, manufactured from the saw dust of three different agro-forest tree species, were lower than the recommended Italian standard, while for nitrogen content, the results were higher than the recommended Italian standard. Among the environmental impacts, Kikar (Acacia nilotica) wood pellets were the major contributor to fossil fuel depletion, followed by ecotoxicity, mineral depletion and acidification/eutrophication. This was primarily due to lubricating oil and urea-formaldehyde (UF) resin used as inputs in the wood pellets biofuel manufacture. Likewise, human health and ecosystem quality was also affected by lubricating oil, UF resin, and saw dust, respectively. In cumulative exergy demand of 1 kg wood pellets biofuel, the highest impact was from Kikar wood pellets for non-renewable fossils, mainly due to lubricating oil used. Difference in environmental impacts, damage assessment, and exergy were examined in three different scenarios for major hotspot inputs by reducing 20% lubricating oil in case 1, 20% UF resin in case 2, and without usage of UF resin in case 3, while marked reduction was observed in ecotoxicity, fossil fuel, and mineral depletion, as well as acidification/eutrophication impact category. Moreover, a pronounced reduction was also noted in the non-renewable fossil fuel category of cumulative exergy demand of one kg of wood pellets biofuel produced.

A comprehensive review of the production, adoption and sustained use of biomass pellets in Ghana

“…Though the benefits of pellets outweigh that of LPG, the life cycle of pellet production causes severe environmental issues like increased air pollution and intense land changes [ 188 ]. However, the evaluation of pellet production cost considers only internal costs of materials, labor, energy and equipment and leaves environmental externalities to be borne by third parties in the form of medical expenses, accident compensation and poor environmental quality [ 232 ]. The GoG and the Ghana environmental protection agency must ensure that environmental impact assessments of pellet projects are carried out per the environmental statutes of Ghana [ 233 ].…”

Environmental, Energy, and Water Footprints of Marble Tile Production Chain in a Life Cycle Perspective

“…Our results are in accordance with Refs. [13][14][15], which analyzed the environmental impacts of the marble production chain using LCA; their results revealed that electricity and fossil fuels are responsible for the GWP impact category [21,[32][33][34]. As there is no LCA of the marble production chain in Pakistan, we compared our results with other allied LCA-based studies; however, this is one of the limitations and weaknesses of the present study.…”

“…As there are no wastewater treatment plant facilities in the marble manufacturing units, as a result, the pollution level increases very quickly in water and soil, and consequently, adversely affects the biotic and abiotic components of the environment [7,20]. Environmental deterioration is not only severely affecting flora and fauna, but it can also affect human beings adversely; therefore, an environmental sustainability assessment of the marble tile production chain is imperative to assess and monitor the pollution level in the air, soil, and water from the marble tile production chain [6]; thus, to calculate its environmental impacts, water footprints, and cumulative energy demand, life cycle assessment (LCA) is applied, which is a recognized tool globally to assess the environmental sustainability of a product or process [21][22][23][24]. LCA estimates and assesses top-ten USA EPA most wanted environmental impacts such as global warming potential, acidification potential, eutrophication potential, abiotic depletion, terrestrial ecotoxicity, marine aquatic ecotoxicity, human toxicity, freshwater aquatic eco-toxicity, ozone layer depletion, and photochemical oxidation of a product across its life cycle stages [23][24][25][26].…”

“…LCA estimates and assesses top-ten USA EPA most wanted environmental impacts such as global warming potential, acidification potential, eutrophication potential, abiotic depletion, terrestrial ecotoxicity, marine aquatic ecotoxicity, human toxicity, freshwater aquatic eco-toxicity, ozone layer depletion, and photochemical oxidation of a product across its life cycle stages [23][24][25][26]. While assessing the environmental impacts of a production line, LCA plays an important role in environmental policy and is also helpful in enhancing product efficiency and cost reduction [21][22][23]. Developed countries applied the LCA approach to their industries to green their products and reduce greenhouse gas (GHG) emissions and other environmental burdens [23]; therefore, the present study is the first of its kind in Pakistan which focuses on the LCA of marble production chain in Pakistan's Small Industrial Estate Mardan (SIEM) to calculate environmental impacts, water footprint, and energy demand of one-tonne marble tile production, from its extraction phase, to final store house or factory gate for investigation of emissions hotspots sources and to perform sensitivity analysis for identification of improvement opportunities in the entire marble production chain in Pakistan.…”

Life cycle environmental sustainability and cumulative energy assessment of biomass pellets biofuel derived from agroforest residues

“…One of the most common methodologies for assessing the environmental impacts of products is life cycle assessment (LCA) [20,[25][26][27]. LCA is a method for examining a product's or process's environmental impact from inception through its final disposal.…”