Waste Incineration Rotary Kiln

Waste Incineration Rotary Kiln

A waste incineration rotary kiln is a piece of equipment used for incinerating solid waste. Its core structure consists of an inclined, cylindrical steel body lined with refractory material. The rotation of the kiln achieves continuous transfer and agitation of the waste, which, combined with an air supply system, completes the combustion process.

Working Principle and System Composition: The equipment operates by rotating the kiln body, causing the waste to tumble and move within the inclined furnace. The flue gas generated after high-temperature combustion enters a secondary combustion chamber to ensure complete oxidation of harmful gases. The system typically includes a feeding device, primary combustion chamber, secondary combustion chamber, waste heat boiler, wet scrubber, bag filter, and activated carbon adsorption unit, forming a complete flue gas purification chain.

Rotary kiln incinerators possess unique technical characteristics in the field of waste incineration, mainly reflected in structural design, process adaptability, operational efficiency, and environmental performance.

1.Advanced and Adaptable Structural Design: The main body of the rotary kiln is an inclined, rotating cylindrical shell. Slow rotation enables the tumbling and forward movement of the material, ensuring full contact between the waste and the high-temperature environment. The kiln interior is lined with refractory materials (such as high-alumina bricks or silicon carbide bricks) capable of withstanding temperatures above 1200°C and resisting corrosion. It is also equipped with a composite sealing system (e.g., a combination of graphite blocks and fish-scale plates) and hydraulic thrust devices, effectively controlling gas leakage and axial displacement of the kiln body. This structure allows it to handle various forms of waste, including solid refuse, liquid waste, and gaseous waste. Safety is enhanced through an inert gas (e.g., nitrogen) protection system and rapid shut-off valves in the feeding system.

2.Flexible Process Control and High Combustion Efficiency: The rotary kiln employs a three-stage temperature zone control (drying zone: 400-600°C, pyrolysis zone: 600-850°C, combustion zone: 850-1000°C). Precise temperature control is achieved by adjusting the ratio of primary to secondary air (typically 1:2) and the flow rate of auxiliary fuel. The residence time of material within the kiln can be co-adjusted by altering the kiln's inclination angle and rotation speed, adapting to different waste characteristics. Variable oxygen combustion technology automatically adjusts oxygen concentration based on load, improving combustion efficiency and reducing CO emissions.

3.Outstanding Environmental Performance and Efficient Flue Gas Purification: The flue gas post-incineration passes through the secondary combustion chamber to ensure complete combustion. It is then purified using a combined process of "SNCR denitrification + activated carbon adsorption + bag filtration + wet desulfurization/acid removal," achieving a denitrification efficiency of over 90%.

4.Balance of Economy and Applicability: Rotary kiln technology exhibits strong adaptability to waste properties and can process complex waste compositions such as hazardous waste, medical waste, and industrial waste. However, the equipment investment and operational costs are relatively high, particularly when treating waste with low calorific value and high moisture content.

In waste incineration, the rotary kiln serves as a core piece of equipment, enabling efficient incineration and treatment of waste through its rotating cylinder. Its functions are primarily reflected in the following aspects:

1.High-Temperature Incineration and Harmful Substance Decomposition: The inclined rotation of the rotary kiln causes waste to tumble and move within it. Combined with high temperatures (up to 1150°C) and air supply, combustion is completed. The secondary combustion chamber configured after the kiln ensures a flue gas residence time exceeding 2 seconds, allowing for full oxidation and decomposition of harmful gases such as dioxins, achieving waste reduction and harmless treatment.

2.Strong Adaptability: The equipment can handle various forms of waste, including solid, liquid, semi-solid, and waste containing high glass/silicon content. It demonstrates strong adaptability to changes in material composition and calorific value, making it particularly suitable for complex industrial hazardous waste and medical waste.

3.Resource Utilization: The waste heat generated during incineration can be recovered via a waste heat boiler for power generation or heating. Simultaneously, the ash and slag can be processed into raw materials for construction, promoting the transformation of waste into resources and aligning with the requirements of a circular economy.

4.Environmental Emission Control: The system is equipped with dust removal equipment, activated carbon adsorption, and a rapid quench system, enabling effective control of dust and harmful gas emissions and ensuring that flue gas indicators meet environmental standards.