-Henan Zhengzhou Mining Machinery

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Introduction

The double-chamber heat storage shaft kiln is commonly called Maerz kiln. Compared with other lime kilns, it has the lowest heat consumption, high activity of calcined lime and low residual carbon dioxide.

Process characteristics of double chamber shaft kiln:

The stone is loaded from the top of the kiln, and the fuel is fed into the upper part of the kiln. The spray guns located at the bottom of the pre-tropical zone are evenly distributed across the section of the kiln. The combustion-supporting air is fed from the upper part of the shaft kiln. The combustion-supporting air is preheated in the preheating zone before mixing with the fuel, and then the calcining flame gas flows through the calcining zone and flows co-currently with the ore to obtain the ore. The calcined waste gas is discharged to the top of the kiln along the preheating belt of the other kiln through the passage connecting the two kilns. Due to the long process of parallel calcination, the lime quality is very good, and due to the alternate operation of the two kilns, the waste gas directly preheats the ore, and the heat is fully utilized, so the unit heat consumption is lower in various kilns.

Features

1. Parallel calcination: This is the technical feature of the double-chamber shaft kiln. Because the high temperature flame contacts the lower temperature material, the heat exchange rate is very high, and the relatively low temperature hot gas contacts the material to be burned. Avoiding over-firing and under-firing, the roasted product has better quality, higher activity, up to 360ml or more, and less residual CO2, generally not higher than 2.5%;

2. High heat utilization rate: Due to the heat storage heat exchange system, high-temperature exhaust gas is discharged through the preheated kiln, and after a long time of heat exchange, the heat is transferred to the material, and the waste heat is fully utilized, thus achieving the purpose of energy saving . The heat consumption per unit product can reach 850kcal/kg, which is relatively low among all existing kiln types;

3. The exhaust gas temperature and dust content are low: the exhaust gas temperature is very low due to the sufficient heat exchange between the exhaust gas and the material, the exhaust gas temperature is 90-130°C under normal conditions, and the dust concentration in the exhaust gas is generally 5-8g/m³ , It is easy to take waste gas purification treatment measures, which is beneficial to reduce environmental pollution;

4. Uniform heat supply: 2×33 burners are evenly distributed inside the kiln, each burner provides heat to the same range of the kiln space, so that the heat supply on the kiln section is even, which is conducive to the uniform and stable roasting of the product;

5. Convenient quality inspection: There are 2×8 quality inspection doors under the kiln, and the fuel supply of the corresponding burner can be adjusted to ensure the quality by checking the product quality of each part;

6. Reliable equipment: Most of the equipment on the shaft kiln adopts hydraulic operation, and the operation is stable and reliable. These equipments include: air and exhaust gas reversing gate, chimney exhaust gas reversing gate, kiln closing gate, feeding hopper gate, discharge device, discharge hopper sealing gate and material level indicator, etc.;

Technical Parameter

Compare items	Sleeve kiln	Double chamber kiln	Double beam kiln
VSK type	BASK	MAERZ	FERCALX
Daily production capacity of single kiln	150—600T/D	300—600T/D	150—500T/D
Fuel calorific value	≥1500Kcal/Nm3	≥800Kcal/Nm3	≥1500Kcal/Nm3
Fuel calorific value	≥2400Kcal/Nm3	≥2400Kcal/Nm3	≥2400Kcal/Nm3
Fuel type	Solid, liquid, gas	Solid, liquid, gas	Solid, liquid, gas
Gas pressure requirements	～17 KPa	～50KPa	～17 KPa
Minimum particle size of raw material	30mm	15mm	15mm
Particle size ratio	1:2	1:2	1:2
Principle of calcination	Partly cocurrent, partly countercurrent	Full-process parallel calcination	Full countercurrent calcination
Lime activity	≥350mL	≥350mL	≥300mL
Light and over burnt rate	≤5%	≤4%	6～8%
Residual CO2 content in lime	≤1.5 %	≤1.5 %	～2%
Enery consumption index（Kcal/kg lime）	900～950×4.18	850～900×4.18	1050～1250×4.18
Power consumption index（Kcal/kg lime）	30～35	22～28	34～40
Annual operating rate	～96%	92～96%	～96%
Total weight	～2800 ton/set	～3200 ton/set	～2600 ton/set
Single kiln investment	～55,000,000 RMB	～50,000,000 RMB	～30,000,000 RMB
Exhaust CO2 concentration	≥32%	≥28%	≥32%