Lignite Dryer for sale

Introduction to Lignite Dryer

Lignite dryer machine is a kind of rotary equipment for dewatering lignite coal. Lignite dryer is brown coal dryer and wood coal drying machine, which can realize continuous, industrial and automatic operation. It comes according to lignite characteristics. Zoneding lignite dryer was born with aim to meet environmental legislation and customers’ need.

To guarantee the quality of lignite and coal slime unchanged after the drying process, Zoneding engineers keep researching and have developed advanced lignite drying technology. Zoneding focuses on controlling the scorching wind temperature and rotating speed to reach higher drying efficiency. Lignite coal dryer machine can dewater the coal slime to the moisture content below 13%, and improve the combustion efficiency.

What is Lignite?

Lignite is a kind of mineral coal with minimum coalification degree. Because it is rich in volatile elements, it is easy to burn and generate smoke. Besides, lignite contains about 6-19% ash, which makes it pollute the environment a lot when burning. Therefore, washing process can improve the purity.

Lignite is a soft, brownish-black coal that represents the youngest stage of coal formation. While abundant worldwide, it includes two key drawbacks:

1. High Moisture Content: Lignite can be more than half water by weight. This “free” and “bound” water does not burn, meaning a significant portion of the energy released when it’s burned is wasted just boiling off the water within the fuel itself.
2. Low Calorific Value: Because of its high water and oxygen content, lignite has the lowest energy density of all coal ranks.

These factors make raw lignite an inefficient, low-value fuel.

Why Dry Lignite?

Drying lignite is not just about removing water; it’s about fundamentally upgrading the material.

• Increase Calorific Value: For every 1% of moisture you remove, the calorific value increases significantly. Drying can often double the energy content per ton. This is the primary answer to how to increase calorific value of lignite.
• Reduce Transportation Costs: You stop paying to transport massive amounts of useless water.
• Create a Stable Product: The drying process, when done correctly, performs a mild torrefaction that makes the lignite hydrophobic (it resists re-absorbing moisture) and stable for long-term storage without degradation.
• Improve Combustion Efficiency: Dried lignite burns cleaner and more efficiently in power plants and industrial boilers.

In addition to this physical characteristic, it is of high moisture and easy to self-ignite, which is a big issue for storage and transportation. Sometimes, good coal cannot meet the fuel requirement, for which lignite is in large demand as an alternative.

In view of the above, lignite drying machine become requisite. Dried lignite is in thermal power plant, chemical industry, metal recycling as well as catalyst supports, adsorbents, sewage purification etc. And the lignite dryer machine can also apply for drying fly ash, coke, coal as well as other granular, paste and powder materials.

What are Applications of Lignite?

The applications for lignite depend entirely on whether it has been dried. Raw, high-moisture lignite is almost exclusively used for one purpose: steam-electric power generation in power plants built directly at the mine site (“mine-mouth” plants). Its high water content makes it uneconomical to transport anywhere else. However, once the lignite is dried and upgraded, its applications expand dramatically. This stable, high-energy product can be sold and transported for use in:

• Co-firing: Blended with higher-rank coals in conventional power plants.
• Industrial Boilers: Used as a primary fuel in energy-intensive industries like cement kilns and paper mills.
• Gasification: Converted into synthesis gas (syngas) for producing chemicals, fertilizers, or liquid fuels.
• Briquette Production: Formed into high-density briquettes for industrial or even domestic heating.

What is the Whole Process of Lignite Drying?

A professional lignite drying system is a carefully staged, closed-loop process focused on safety and efficiency.

1. Crushing & Sizing: Raw lignite is first crushed to a more uniform size (e.g., under 30mm) for consistent drying.
2. Airtight Feeding: The wet lignite is fed into the dryer through a sealed system, typically using a rotary airlock valve to prevent oxygen from entering.
3. Low-Oxygen Drying: Inside the rotary drum, the lignite is tumbled through a hot, inert gas stream (recycled flue gas with <5% O2) to drive off moisture without causing combustion.
4. Cooling & Stabilization: The hot, dry lignite is discharged through another airlock into a sealed cooling conveyor to bring it to a safe temperature before exposure to air.
5. Dust Collection & Safety Monitoring: The entire system is connected to a dust collection unit, with CO and O2 monitors constantly sampling the gas for early fire detection.

What is a Lignite Dryer?

A lignite dryer is a highly specialized piece of industrial equipment, almost always a modified rotary dryer for lignite. It is fundamentally different from a standard dryer because it is engineered as a sealed, oxygen-starved pyrolysis environment. The primary goal is to heat the lignite to drive off water without providing the oxygen needed for it to burn. It is a chemical reactor first and a dryer second. The entire design philosophy revolves around mitigating the extreme fire and explosion risk associated with dried lignite dust.

Applications of Lignite Rotary Dryer

• Coal slime, raw coal, any kinds of fine coal in coal industry;
• Iron powder, copper powder, zinc powder and any other metal granular materials in ore processing and mining;
• Clay, limestone, sand, silica/quartz sand, bentonite, slag, etc. in building materials
• Non-thermal sensitive materials in metallurgy;
• Other kinds of powder and particle that need to be dried specially.

How Lignite Dryer Works

Lignite Dryer adopts the new technology of drying after crushing, which realizes the industrialization, automation and continuous production.  When the lignite dryer machine works, wet lignite is fed into the crushing equipment firstly. Then low-temperature four-stage drying process is introduced and dries the wet lignite to the humidity of 13% or below. 

Working Principle of Lignite Dryer

Structural Functions of the Four Drying Stages of Lignite Dryer

First Level: 400 ℃, high temperature removes most of the moisture and make sure the lignite not change chemically;

Second Level: 300 ℃, strong wind produced works in high efficiency to ensure that the lignite is not coking;

Third Level: 120-210℃, with the crushing function of the cleaning devices inside the cylinder, wet lignite flows in the cylinder and is dried;

Fourth Level: 60-80℃, the removal of water depends on low-temperature current produced by the induced draft system.

Advantages of Zoneding Lignite Drying Machine

• The realization of zero horizontal thrust reduces the bearing of the retaining wheels, so the cylinder rolls stably and reliably;
• High anti-overload capacity of the lignite dryer bears a large production capacity. As a result, the fuel and the cost are saved;
• New structure helps to strengthen the cleaning of lignite and heat transformation, which erases the sticky slime on the inner wall.

Therefore, lignite dryer can take full advantage of the coal resources and reduce the emission concentration, so as to achieve energy-saving emission reduction and environmental protection objectives.

General Specification