Highly efficient and sustainable decarbonisation of bright annealing process by recovery and reuse of H2

Introduction

Bright annealing is an annealing process performed in a vacuum or controlled atmosphere containing inert gases, which reduces the surface oxidation to a minimum. This results in a brighter surface, a much thinner oxide layer, reduced hardness, increased ductility, and no internal stresses. It also reduces the risk of corrosion, material fracture, cracking, and distortion.

Process Description

Bright annealing is carried out in a furnace full of hydrogen (100% H2) at temperatures ranging between 1,040°C and 1,100°C, followed by rapid cooling. In the case of fully continuous plants, such as the one of SMSTI, which serves as both the coordinator and end user, this hydrogen flow is fully volatile and dispersed after its use in the process.

Project Objectives

The main objective of LIFE H2Reuse is to mitigate the effect on climate change of the bright annealing process for tubes in the steel industry by proposing two innovative technical solutions:

1. Recovery of the wasted H2 from the annealing process.
2. Reuse of H2 as fuel in the H2 burners.

Specific objectives include:

• Reduction of CO2 emissions.
• H2 recovery, avoiding waste of resources.
• Reduction of energy consumption.
• Demonstration of the new process.
• Assessment of economic savings and business opportunities.

Innovation and Development

The idea of recovering the atmospheric gas for use as fuel gas is an innovation that is not yet available on the market. Additionally, while H2 burners are already present on the market, they are still in the development phase to increase their effectiveness and mitigation effects.

The innovations will be developed and tested in a real environment to demonstrate the achievement of the technical, environmental, and socio-economic expected KPIs.

Market Exploitation

This process will then be exploited in the market, targeting, among others, Tenova's numerous roller hearth furnace plants, which also use an atmospheric gas with a high hydrogen content (up to 100%). These plants could benefit from the project results to reduce carbon footprint, avoid waste of resources, and reduce costs.