Effects on sustainability by redesign of a 1° stage gas turbine nozzle ring from investment casting to additive manufacturing: a life cycle environmental impact comparison

Abstract

Energy companies are committing to protect the environment and reducing their product carbon footprint. To accomplish these objectives, they need to establish their baseline, including the life cycle emissions of key products and services. The life cycle emissions assessment will help to support customers and suppliers, many of which have set their own carbon footprint reduction targets, in finding opportunities to reduce their own environmental impact. The purpose of this study is to compare the environmental impact of two manufacturing processes, namely Additive Manufacturing (AM) and Investment Casting (IC), for the production of a 1° stage gas turbine nozzle ring in order to determine which method is the most sustainable on the Life Cycle. AM technologies brought to the world new design possibilities which become very useful for those items whose production rate decreases due to a drop in demand or a suspended production. In this case study, which considers a serviced Gas Turbine, the production volume is very low compared to the standard production of a gas turbine. For this reason, AM revealed to be a key strategy for the investigated product for environmental, cost and lead time sustainability. The LCA is conducted under Cradle-to-Gate boundaries, hence it investigates every energy/material input and output from the raw materials extractions, to the production of the good at the gate of the company ready for shipping. Raw material extraction, powder atomization, machining, finishing, and coating phases are included into the analysis. The choice of the manufacturing strategy requires different materials and different suppliers are involved into the manufacturing chain, which means also differences in transportation and sources for electricity production.