What is a Circular Cooler?

A Circular Cooler is a key piece of equipment in the sintering process of the steel industry. Its primary function is to rapidly cool down hot sinter to a temperature suitable for transportation and further use in the blast furnace. By using ring-shaped cooling fans to blow air evenly through the sinter bed, the circular cooler ensures the strength and quality of the sinter.

During this cooling process, however, a large amount of low-temperature flue gas (120℃–180℃) is generated. If released directly into the atmosphere, it leads to significant energy waste and increased environmental burden. Therefore, recovering and utilizing the waste heat from circular coolers has become an urgent requirement for steel plants aiming to save energy and reduce emissions.

Why Waste Heat Recovery is Essential

Traditionally, waste heat recovery in sinter plants has focused on high-temperature sections (such as steam recovery). However, utilization of low-temperature flue gas remains limited, keeping the overall recovery rate at only about 50%.

With the global carbon neutrality (“dual carbon”) goals, improving the efficiency of low-temperature waste heat recovery is now a crucial step for the sustainable development of the steel industry.

BOOYO' s Technology: Power-Free Low-Temperature Flue Gas Recovery

Shandong BOOYO Heavy Industry has developed a power-free low-temperature flue gas recovery system for circular coolers. This innovative system uses the residual pressure of the circular cooler cooling fans to drive flue gas through waste heat boilers and economizers, thereby heating circulating or process water. The system requires no additional power supply, ensuring stable and reliable operation.

Typical parameters:

• Flue gas temperature range: 120℃ – 180℃

• Hot water outlet temperature: 90℃

• Flue gas handling capacity: 2.3 million Nm³/h

• Heat recovery capacity: 40.6 million kcal/h

• Annual coal savings: over 3,000 tons

• Annual economic benefits: approx. RMB 30 million

Key Advantages

1. Outstanding Energy Savings – Utilizes residual pressure, no extra power consumption.

2. Environmental Protection – Reduces flue gas outlet temperature and lowers pollutant emissions.

3. Strong Economic Benefits – Cuts down on fuel costs, delivering remarkable annual savings.

4. Proven Reliability – Successfully applied in large-scale steel plants, stable with low maintenance.

5. Sustainability-Oriented – Supports steel plants in achieving green and low-carbon development goals.

Case Study – Shandong Iron & Steel Group Rizhao Base

At the Rizhao Steel Base of Shandong Iron & Steel Group, two 500m² sinter machines were equipped with circular coolers. Each cooler was fitted with a three-stage flue gas hot water recovery unit to produce network circulating water (supply temperature: 110℃, return: 80℃), providing heat for absorption chillers.

• Inlet flue gas temperature: 230℃

• Outlet flue gas temperature: 120℃

• Flue gas flow rate: 420,000 m³/h (up to 406,000 m³/h steady operation)

• Hot water parameters: Inlet 80℃ → Outlet 110℃

• Operation status: Stable and reliable since commissioning, essentially maintenance-free aside from expansion modifications

• Economic benefits: Over RMB 30 million annually

This case demonstrates that BOOYO' s circular cooler waste heat recovery technology is not only technically feasible but also delivers outstanding results in large-scale steel bases.

About Shandong BOOYO Heavy Industry Group

Shandong BOOYO Heavy Industry Group is a leading enterprise dedicated to efficient energy utilization. The company integrates design, R&D, manufacturing, sales, and installation, serving industries such as metallurgy, power generation, petrochemicals, and energy.

• Scale: 4,400 mu land area, 160,000 m² workshops, 1,760 employees, including over 110 engineers.

• Production capacity: More than 5,000 heat exchangers annually, total capacity exceeding 500,000 tons.

• Product portfolio: Heat exchangers, pressure vessels, waste heat boilers, condensers, evaporators, and towers.

• Technical strength: Equipped with advanced automatic welding lines, CNC cutting machines, and laser systems, adopting cutting-edge KD-TIG welding technology to ensure product quality.

• Market presence: Widely applied in steel, petrochemical, power, coking, and coal chemical industries, with products exported worldwide.

• Innovation: Undertakes major national and provincial energy-saving projects, pioneering in low-temperature flue gas recovery and circular cooler energy-saving solutions.

Guided by the philosophy of professionalization, integration, and internationalization, BOOYO is committed to becoming a world-class supplier of waste heat recovery and energy-saving equipment.