Heat Recovery in Coke Batteries

In 2020, a heat recovery project was started for a major producer of special foundry coke, located at its production center in Trubia (Asturias, Spain), with a capacity to produce 125,000 tons/year of coke, with the aim of decarbonizing its production process and reducing its operating costs.

This project consists of recovering the energy contained in the exhaust gases from the coke batteries (where the transformation of coal into coke, fuel and essential reagent in the steel manufacturing process takes place). The potential for energy recovery in these gases is very high as temperatures of upto 900ºC are reached. AITESA’s scope includes: Design, supply, assembly and commissioning of a natural circulation water-tube boiler to generate 17.6 ton/h of superheated steam at 70 bar(g) and 480ºC, which corresponds to a power of 14.3 MWt. This steam feeds a turbine for electric power generation to be consumed within the plant. It also includes a tube cleaning system by steam blowing, as well as all the instrumentation and control valves for the safe operation of the boiler. In parallel to the energy recovery, this project introduces a treatment system for cleaning the gases after passing through the recovery boiler, which eliminates 70% of the SOx content and 86% of the particles present. AITESA commenced the turnkey assembly of the boiler package in November 2020 with plant start up in July 2021.

Thanks to this recovery boiler and its subsequent use in electricity generation, CO2 emissions are reduced by 15,000 tons/year, generating a positive impact on the environment equivalent to planting 750,000 new trees annually.