Lime Kiln

Used to produce quicklime by the calcination of limestone (calcium carbonate)

The chemical equation for this reaction is: CaCO3 + heat → CaO + CO2

This reaction takes place at 900°C (at which temperature the partial pressure of CO2 is 1 atmosphere), but a temperature around 1000°C (at which temperature the partial pressure of CO2 is 3.8 atmospheres) is usually used to make the reaction proceed quickly

Excessive temperature is avoided because it produces unreactive, dead-burned lime

Rotary kilns started to be used for lime manufacture at the start of the 20th century and now account for a large proportion of new installations

The early use of simple rotary kilns had the advantages that a much wider range of limestone size could be used, from fines upwards, and undesirable elements such as sulfur can be removed

Our lime kiln features in, convenient and reliable control of the production process, less wearing parts, high rates of operation, the Lime kiln also has strong structure, stable operation, low energy consumption, high-quality products,large capability from the kiln and so on advantages, we can also offer advanced efficient shaft preheater, five grade cyclone preheater

Technical features:

Take the 300T/d kiln as example, it can be regulated within 180 to 300T/d range without influencing quality and consumption targets

Chalk size: 400mm to 80mm

Size range ratio: 1:2

Kinds of fuel: natural gas, oil, cola dust, coke oven gas, coal gas of low heat value, and mixed fuel of all kinds of fuel (gas and gas, gas and liquid, gas and solid, liquid and solid, and more)

Lime products: fine lime and high activity (reaching 360mL, 4N HCL 10 minutes)

The ratio of lime stone under-firing and over-baking is 5 to 8%

Low heat wastage: they can make full use of heat energy when primary air passes, fuel gas is preheated when secondary air passes, cooled lime is preheated, fuel is burned completely

Structure features and process instruction

Kiln body: rectangular or cylindrical

With double-deck burner girders in the kiln body with periphery burners in the middle kiln body

Waste gas drawing-out girder is set on the kiln top

Divided into five parts: material storage zone, preheated zone, calcining zone, posterior calcining zone,cooling zone

Storage zone: a part between kiln gas drawing-out device and crown, it is used for storing adequate lime stone in order not to stop producing when the crown feed device needs short-term maintenance

Preheating zone: a part between kiln gas drawing-out device and upper burner girder, used to preheat lime stone

Calcining zone: a part between upper burner girder and lower girder, where lime stone is calcined into fine lime, it's height can be regulated according to requirement of quality or lime stone physical property

Posterior calcining zone: a part between lower burner girder and lower gas drawing-out girder, the lime that was calcined will gain the even and refine quality and raise the activity, when through this zone that has the high temperature and no pressure

Cooling zone: a part between lower burner and lime output, cooling air comes into the kiln from the bottom cools lime stone to 75c and comes out of the kiln, heated secondary air comes into calcining zone to help burn

Tow-girder burning device is central part of the kiln

Some fuel (such as gas, liquid, and solid) feed pipes are placed into the girder the burner mixes fuel with the combustion air even

In order to protect the burner girder working at high temperature in the calcining zone, medium (water or heat oil) enters the burner girder sandwich and circulates to cool

Medium (water or heat oil) passes the cooler to cool

Primary air preheated by waste air, passes the burner girder and enters the kiln

Safely when medium (water or heat oil) temperature rises above certain temperature

The stand-by pump makes surn medium (water or heat oil)can keep circulating)

Gas extracing girder is on the kiln top

The quantity of pipes is decided by the kiln size

There are many evenly-distributed opens downside of the pipes kiln gas is extracted by the gas extracing girder through the opens to ensure negative pressure of the kiln section is evenly distributed

The kiln has dual-pressure system

The small blower blows secondary air.Secondary air comer into the cooling zone to cool line even

This makes the part under the calcining zone keep positive pressure

Dual-pressure system controls the quantity of primary air and secondary air more precisely than all negative pressure system

Waste air of the kiln top is extracted by the run-off regulator device to keep negative in the zones above the calcining zone and make heat temperature enen on the kiln section

The regulating range of air quantity is 10 to 100%

Regulating burning air quantity makes the kiln working under the best operating condition, saves energy and cuts down production cost