What is a dryer hot air furnace

Dryer hot air furnace is the core component of drying equipment, responsible for providing stable hot air for drying materials (e.g. grain, wood, chemical products, etc.). The following is a detailed introduction about dryer hot air furnace:

1. Working principle of dryer hot air furnace

The hot air furnace generates heat by burning fuel (coal, natural gas, biomass, etc.) or electric heating, and then passes the heat to the air through the heat exchanger to form high-temperature clean hot air, which is sent into the dryer by the fan to dry the materials.

Basic workflow:

Fuel combustion (or electric heating) produces high temperature flue gas.

Heat exchange: high temperature flue gas passes through heat exchanger (indirect heating) or mixes directly with air (direct heating).

Hot air conveying: clean hot air is sent into the dryer by the fan to dry the materials.

Exhaust emission: part of the hot and humid air is discharged and part of it can be recycled to improve energy efficiency.

2. Common types of dryer hot air furnace

Coal-fired Hot Air furnace/Gas-fired Hot Air furnace/Biomass Hot Air furnace/Electrically Heated Hot Air furnace/Oil-fired Hot Air furnace

3. The main points of the selection of dryer hot air furnace

(1) According to the drying material selection

Food, medicine: need clean hot air (indirect heating, to avoid smoke pollution).

Chemical industry, minerals: high temperature, corrosion-resistant materials (such as stainless steel heat exchanger).

Wood, agricultural products: biomass furnace can be used to reduce fuel costs.

(2) According to the hot air temperature demand

Low temperature drying (<100℃): electric heating or steam heat exchange.

Medium temperature drying (100~300℃): gas, oil or biomass furnace.

High temperature drying (>300℃): coal-fired or special high temperature resistant design.

(3) Calculation according to capacity (air volume & air temperature)

Thermal power (kW) = air volume (m³/h) × temperature rise (℃) × specific heat capacity of air (0.34) ÷ thermal efficiency (80~95%).

Example: the dryer needs 5000m³/h of hot air and the temperature rise is 100℃, then the thermal power ≈ 5000×100×0.34÷0.9 ≈ 189 kW.

(4) Environmental requirements

Coal/biomass-fired furnace needs to be matched with dust removal (bag dust removal, cyclone dust removal).

Gas/electric heating furnace is more in line with strict emission standards.

4. Common Problems and Maintenance

(1) Unstable hot air temperature?

Check the combustion system (gas pressure, coal supply).

Clean the heat exchanger of accumulated ash to improve the efficiency of heat exchange.

(2) Black smoke from hot air furnace?

Coal / biomass furnace combustion is not sufficient, adjust the air intake or fuel particle size.

Check whether the dust removal system is clogged.

(3) How to save energy?

Install waste heat recovery device (such as heat pipe heat exchanger).

Adopt automatic temperature control system to avoid waste of overheating.

5. Recommended mainstream brands in the market

Domestic brands: Zheng pot, Zoomlion Thermal Technology, Zhengzhou Bona (cost-effective).

International brands: BALTUR (Italy), Weishaupt (Germany) (high-end precision temperature control).

Summarise

The choice of dryer hot air furnace needs to be considered comprehensively Fuel costs, environmental requirements, drying temperature and air volume requirements. Coal-fired furnace is economical but polluting, gas furnace is clean and efficient, electric heating furnace is accurate but high power consumption. It is recommended to match the model according to the actual production demand, and regular maintenance to ensure thermal efficiency and life.

If you need more specific selection programme, you can provide drying materials, capacity and temperature requirements, I can help you calculate the recommended model!