Environmental performance of straw-based pulp making: A life cycle perspective

摘要

Highlights•Environmental performance of straw-based pulp making was evaluated through LCA.•Energy production and chemical inputs are the main contributors to environmental impacts.•Straw-based pulp making causes higher environmental impacts than wood-based pulp.•Bio-based carbon emissions should not be overlooked in pulp making industry.Graphical abstractDisplay OmittedAbstractAgricultural straw-based pulp making plays a vital role in pulp and paper industry, especially in forest deficient countries such as China. However, the environmental performance of straw-based pulp has scarcely been studied. A life cycle assessment on wheat straw-based pulp making in China was conducted to fill of the gaps in comprehensive environmental assessments of agricultural straw-based pulp making. On average, the global warming potential (GWP), GWP excluding biogenic carbon, acidification potential and eutrophication potential of wheat straw based pulp making are 2299kg CO2-eq, 4550kg CO2-eq, 16.43kg SO2-eq and 2.56kg Phosphate-eq respectively. The dominant factors contributing to environmental impacts are coal consumption, electricity consumption, and chemical (NaOH, ClO2) input. Chemical input decrease and energy recovery increase reduce the total environmental impacts dramatically. Compared with wood-based and recycled pulp making, wheat straw-based pulp making has higher environmental impacts, which are mainly due to higher energy and chemical requirements. However, the environmental impacts of wheat straw-based pulp making are lower than hemp and flax based pulp making from previous studies. It is also noteworthy that biogenic carbon emission is significant in bio industries. If carbon sequestration is taken into account in pulp making industry, wheat straw-based pulp making is a net emitter rather than a net absorber of carbon dioxide. Since wheat straw-based pulp making provides an alternative for agricultural residue management, its evaluation framework should be expanded to further reveal its environmental benefits.