How much natural gas is needed to burn one ton of lime in a lime vertical kiln
In the field of lime production, lime shaft kiln has become the choice of many enterprises due to its compact structure and small footprint. With increasingly strict environmental requirements, the application of natural gas as a clean energy source in lime calcination is becoming more and more widespread. So, how much natural gas does it take to burn one ton of lime?
Theoretical basis for natural gas consumption
The essence of lime calcination is the chemical reaction of calcium carbonate decomposing into calcium oxide and carbon dioxide, which requires the absorption of a large amount of heat. In theory, the firing of one ton of lime requires 890000 to 1250000 kilocalories of heat, which depends on the kiln type, design parameters, and production process. Natural gas, as an efficient and clean fuel, typically has a calorific value between 8000 and 11000 kcal/m3, providing a stable heat source for lime calcination.
Natural gas consumption in actual production
In actual production, the natural gas consumption for burning one ton of lime in a lime kiln is not a fixed value, but is influenced by multiple factors. Based on industry data and typical cases, the natural gas consumption per ton of lime is usually between 110 and 140 cubic meters. Taking the third-generation energy-saving lime shaft kiln operated by a certain enterprise as an example, its natural gas consumption remains stable at around 110 cubic meters per ton, which is in line with the industry's advanced level.
The impact of different kiln types and processes on natural gas consumption is significant. For example, by optimizing the heat exchange system, the double chamber lime kiln can increase the heat utilization rate to an extremely high level, and the natural gas consumption can be controlled within a low range; However, traditional single chamber kilns may have higher consumption due to significant heat loss. In addition, the quality of limestone (such as purity, particle size distribution) and the control of calcination temperature (usually not exceeding 950 ℃) also directly affect energy consumption. If the impurity content in limestone is too high or the calcination temperature deviates from the optimal range, it may lead to heat waste or a decrease in product quality.
Cost composition of natural gas consumption
The price of natural gas is a key factor affecting the production cost of lime. Taking the current market situation as an example, natural gas prices fluctuate between 1.2 and 2.5 yuan per cubic meter. Based on the consumption of 110 cubic meters of natural gas per ton of lime, the fuel cost is approximately 132 to 275 yuan/ton. It is worth noting that if enterprises use self-produced gas (such as blast furnace gas, coke oven gas) or by-product gases such as calcium carbide tail gas, the cost can be further reduced. For example, when using coke oven gas to calcine lime, the consumption per ton is about 260 to 330 cubic meters, but if the enterprise has its own gas source, the cost may be lower than the natural gas solution.
Energy saving technology and optimization direction
To reduce natural gas consumption, enterprises can start from the following aspects:
Kiln type upgrade: High efficiency kiln types such as double chamber kiln and sleeve kiln are adopted, and heat loss is reduced by optimizing the heat exchange structure.
Waste heat recovery: Utilizing flue gas waste heat to preheat combustion air or limestone raw materials, improving energy utilization efficiency.
Intelligent control: Accurately adjust fuel supply and calcination temperature through automated systems to avoid excessive combustion or insufficient heat.
Raw material pretreatment: Screening, crushing, and pre drying limestone to reduce calcination difficulty and energy consumption.
The natural gas consumption for burning one ton of lime in a lime shaft kiln is influenced by multiple factors such as kiln type, process, and raw materials, with an industry average of about 110 to 140 cubic meters per ton. Enterprises need to choose suitable kiln types and fuel schemes based on their own conditions, and reduce production costs through energy-saving technology upgrades to adapt to market changes and environmental requirements.
