Enhancing Energy Efficiency in the Steel Industry

Temperature of Stainless Steel Plates

Current Challenges in Energy-Saving Projects

Despite advances in energy-saving technologies, small energy-saving projects face obstacles. The long investment recovery period and underdeveloped market mechanisms discourage companies from investing. Major energy-saving measures with clear benefits have been widely adopted, but smaller projects are often overlooked due to limited resources. Utilizing the energy-saving service market and contract energy management can help address these challenges, ensuring technology, capital, and operational management are effectively managed for mutual benefit.

Achievements in Energy Conservation

Over the past decade, energy consumption per ton of steel has consistently decreased. However, challenges remain, particularly in waste heat and energy utilization. The steel industry involves complex energy consumption, conversion, regeneration, and transportation processes, characterized by high temperatures reaching 1500°C. About 40% of primary energy in steel production is released as heat. The waste heat generated per ton of steel is approximately 8-9 GJ, categorized into by-product gas, exhaust waste heat, solid waste heat, and waste steam and water heat.

Progress in Waste Heat and Energy Utilization

Significant advancements have been made in waste heat and energy utilization technologies. The dry PT deployment rate in large enterprises exceeds 90%, and the dry quenching ratio is 42.3%. Key enterprises have adopted efficient technologies like gas-steam combined cycle generator sets (CCPP), enhancing energy conversion. Technologies such as saturated steam power generation, blast furnace gas burning, and waste heat utilization in various processes have been widely implemented, resulting in improved energy efficiency and reduced gas loss rates.

Issues in Waste Heat and Energy Recycling

Waste heat and energy face issues like scattered distribution and uneven quality, leading to inefficient recycling. For example, by-product gas recovery involves significant capital but may result in ineffective recycling if suitable users are not found. Long-distance transportation of medium and low-temperature steam causes high energy consumption and heat loss. Additionally, steam systems often release large amounts of steam without efficient utilization, especially in summer.

Addressing Energy Management Challenges

To improve energy efficiency, enterprises need to adopt unified energy management and economic adjustment measures. Media use in energy-consuming equipment must be optimized to prevent competition for high-quality energy, which leads to low overall energy efficiency. Furthermore, the energy level and temperature matching should be achieved to enhance the utilization of waste heat and energy.

Coping with New Challenges

The steel industry faces new challenges as it scales up production. Although gas emission rates are declining, gas loss remains significant. Effective allocation and use of gas resources, improved gas buffer systems, and reduced gas emission loss rates are essential. Enterprises must transition from converting waste heat solely into electricity to comprehensive utilization methods, such as producing hydrogen and methanol from coke oven gas.

Future Directions

Enterprises should develop high-temperature, high-pressure parameter units to improve thermoelectric conversion efficiency and phase out small-scale units. Low-temperature waste heat resources, including blast furnace slag washing water and turbine cooling water, offer significant energy-saving potential. Energy-saving efforts should focus on enhancing waste heat quality through cascade utilization and developing regional thermal energy systems.

Harmonious Development with Rural Areas

Steel companies, traditionally seen as high energy consumers and polluters, must promote green transformation and harmonize with rural development. By building circular economy industrial chains and utilizing waste heat for rural heating and other purposes, steel companies can achieve sustainable growth and contribute to rural development.

Policy Improvements Needed

Policy obstacles, such as difficulties in obtaining grid connection approval and high grid-connection costs, hinder waste heat and energy utilization. Policymakers should develop reasonable policies and pricing systems to encourage steel mills to build self-contained power plants. Financial incentives for waste heat and energy utilization projects must also be increased to support the industry’s energy-saving initiatives.