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

Area of Science:

• Environmental Science
• Industrial Ecology
• Pulp and Paper Engineering

Background:

• Agricultural straw pulp production is crucial for countries with limited forest resources, like China.
• The environmental performance of straw-based pulp manufacturing remains understudied.
• This research addresses the need for comprehensive environmental assessments of agricultural straw-based pulp production.

Purpose of the Study:

• To conduct a life cycle assessment (LCA) of wheat straw-based pulp production in China.
• To identify key environmental impacts and their contributing factors.
• To compare the environmental performance of wheat straw pulp with other pulp types.

Main Methods:

• Life Cycle Assessment (LCA) methodology applied to wheat straw pulp production in China.
• Quantification of environmental impact potentials: global warming potential (GWP), GWP excluding biogenic carbon, acidification potential, and eutrophication potential.
• Analysis of dominant factors contributing to environmental impacts, including energy and chemical inputs.

Main Results:

• Average environmental impacts: GWP of 2299 kg CO2-eq, GWP excluding biogenic carbon of 4550 kg CO2-eq, acidification potential of 16.43 kg SO2-eq, and eutrophication potential of 2.56 kg Phosphate-eq.
• Key impact contributors: coal and electricity consumption, and chemical inputs (NaOH, ClO2).
• Wheat straw pulp production shows higher environmental impacts than wood and recycled pulp, but lower than hemp and flax pulp.

Conclusions:

• Reducing chemical input and increasing energy recovery significantly mitigate environmental impacts.
• Wheat straw pulp production is a net emitter of carbon dioxide when carbon sequestration is considered.
• Further evaluation frameworks are needed to fully understand the environmental benefits of wheat straw pulp production as agricultural residue management.