Abstract
In energy-intensive industrial processes such as cement, steel, and glass production, only a portion of the generated heat is used directly in the process, while the remainder is typically released into the atmosphere via flue gases. Waste Heat Recovery (WHR) systems utilize this waste heat to generate electricity, offering both economic benefits and environmental gains. This article outlines the operating principles of WHR systems, their implementation in the cement industry, and the technical and economic advantages of sonic soot blower systems as an alternative to conventional mechanical cleaning methods.
1. Basic Principle of WHR Systems and Industrial Applications
The cement industry is one of the most energy-intensive industrial sectors in terms of thermal and electrical energy consumption. Energy costs can account for 60–70% of total production expenses. Therefore, heat recovery is of critical importance. WHR systems direct the flue gas discharged from preheaters and clinker coolers to boilers known as SP (Suspension Preheater) and AQC (Air Quenching Cooler) Boilers, where steam is produced. This steam is sent to a turbine to generate electricity using a generator.
The steam generated in the SP Boiler is redirected to the raw mill through the ID fan, while in the AQC Boiler, the steam enters the turbine system directly, and the exhaust gas is released into the atmosphere via electrostatic precipitators.
2. Fouling and Cleaning Issues in WHR Systems
Heat exchanger tubes in WHR boilers are exposed to powdery clinker and micronized particulate deposits carried by the flue gas. These deposits lead to:
- Reduced heat transfer efficiency,
- Decreased steam generation capacity,
- Increased flue gas temperature,
- Clogging and unplanned shutdowns.
Cleaning is typically performed during annual overhauls, often manually, resulting in prolonged downtime and labor-intensive maintenance.
3. Limitations of Conventional Cleaning Systems: Mechanical Hammering
Some boiler manufacturers integrate mechanical hammering systems into the piping network. These systems:
- Apply timed mechanical impacts to the pipes to dislodge deposits,
- Provide insufficient cleaning for long tube bundles,
- Cause tube erosion, perforation, and steam leaks over time,
- Lead to clinker dust hardening in bunkers upon contact with steam, resulting in blockages,
- May cause forced outages lasting 7–10 days in severe cases.
4. Advantages of Sonic Horn Cleaning Systems
Sonic horn systems are particularly well-suited for WHR boilers due to the following reasons:
- Relatively low internal boiler temperatures,
- Deposits are typically micron-sized and powdery,
- Sound waves effectively penetrate between finned tubes,
- Regular acoustic pulses enable in-process deposit removal.
Technical parameters:
- Frequency: 75–300 Hz
- Pulse duration: 5–15 seconds
- Interval: Every 7–12 minutes
These systems loosen deposits through resonance without physical contact, maintaining the mechanical integrity of the tubes.
5. Economic Evaluation and Return on Investment
- Sonic systems have low installation costs,
- Cleaning occurs during operation, avoiding production loss,
- Reduces labor required for cleaning and maintenance,
- Payback period is typically 6–10 months,
- CO₂ emission reduction provides potential carbon credit income.
6. Conclusions and Recommendations
In WHR systems, acoustic cleaning technologies offer contemporary and economical solutions for energy-intensive industries such as cement production, contributing to:
- Improved energy efficiency,
- Enhanced emission control,
- Process reliability and continuity,
- Reduced maintenance costs
Alanlarında çimento ve benzeri enerji yoğun sanayiler için çağdaş ve ekonomik çözümler sunar.
References
- Hasanbeigi, A., Price, L., Lin, E. (2012). Emerging Energy-efficiency and CO₂ Emission-reduction Technologies for Cement and Concrete Production: A Technical Review. Renewable and Sustainable Energy Reviews.
- KEMA. (2010). Waste Heat Recovery in Industrial Facilities. European Commission Report.
- USER Mühendislik. (2023). Sonic Soot Cleaning Systems Catalog.
- International Finance Corporation (IFC). (2014). Waste Heat Recovery for the Cement Sector: Market and Supplier Analysis.
