Decarbonisation Technology - February 2022 Issue

Energy-intensive industries

Each of the main industries – cement, glass, steel, aluminum – has its own challenges and solutions.

The steel industry appears to have a clearer pathways, more scrap recycling, blast furnace/ basic oxygen furnace to direct reduced iron and electric arc furnace with decarbonated electricity and hydrogen as a reducing agent. For the aluminum industry , which uses an electrolytic process, it is by recycling, using carbon neutral (inert) anodes and decarbonated electricity. The glass industry offers some similarities with cement and lime in that the process itself releases CO 2 , not just from carbon-based fuels combustion. However, the ratio is opposite. Use of recycled glass, energy efficiency, (recuperators), regenerative furnaces, hydrogen substitution to natural gas, oxycombustion, electric furnaces, and down the road also CO 2 capture and utilisation are the various pathways. The cement industry is following many pathways that can be summarised as: fewer fossil fuels, less clinker in cement, less cement in concrete, less concrete in construction and accelerated carbonation. electrification.

Iron ore

H storage

Electricity

HBI storage

HBI

EAF

Grid integration

DRI/HBI

Scrap/lime/ carbon

Electrolyser

Scrap/steel/ Fe+FeOx

Source: DOE Technology Acceleration Overview 2021

Electric power

Residual gas

Electric power

Cleaning and separation

Dust

Fuel

Waste gas

(Hybride) furnace (oxy-fuel, air-fuel)

Water

Air/oxygen

Heat

Storage

Water electrolysis

Water

Methanation (CH, CHOH,...)

Fuel

Storage

Electric power

Local gas grid

District heat

Source: SynErgie project - JARA

Clinker

Cement

Concrete

Carbonation

Construction

at the clinker cooler exhaust) are combined and go through another heat exchanger to vaporise the working fluid that will drive the turbine, which in turn powers the generator. The vapour is then condensed and returned to close the cycle. A benefit of this arrangement is that other sources of heat can be used and combined to generate

more electricity – for instance, thermal solar plant with parabolic trough collectors or geothermal sources. So, multiple sources of heat could drive a single generator. This is a perfect example that shows decarbonisation does not necessarily mean wasted cost. CO 2 reduction cannot be compared directly to