Mathematical Model for Alternative Fuel Combustion in a Rotary Cement Kiln Burner

Abstract

Abstract-Increased use of alternative fuels in cement kilns is a trend in the world. However, replacing fossil fuels like coal with different alternative fuels will give various impacts on the overall kiln process due to the inherent fuel characteristics. Hence, it is important to know to what extent the fossil fuels can be replaced by different alternative fuels without severely changing process conditions, product quality or emissions. In the present study, a mathematical model based on a mass and energy balance for the combustion of different alternative fuels in a cement rotary kiln was developed. First, the impact of different fuel characteristics on kiln gas temperature, kiln gas flow rate and air requirement were observed by using coal (reference case), meat and bone meal (MBM), two different wood types, refuse derived fuel (RDF) and a mixture of saw dust and solid hazardous waste as the primary fuel. It was found that the key process parameters depend largely on the chemical characteristics of the fuel. It appears that MBM shows quite different results from other alternative fuels investigated. Next, simulation of combustion of a mixture of coal and MBM in the rotary kiln burner was carried out in three steps in order to find the reduction in production capacity compared to the reference case. Around 9% of reduction in clinker production rate could be observed when replacing 59% of the coal energy input. Results from a full-scale test using the same mixture of coal and MBM verified the simulation results.Index Terms-Air requirement, alternative fuels, production capacity, rotary cement kiln burner.

Industrial Wastes and By‐products as Alternative Fuels in Cement Plants: Evaluation of an Industrial Symbiosis Option

“…, Ariyaratne et al. ), the multidimensional representation (tables , , and appendices A and B in the supporting information available on the Journal's website), without being case specific, enables simultaneous consideration of any number and type of AFs and decouples the impact of AF composition and feed‐rate uncertainty. It allows peer comparative assessment of various AF scenaria under the same kiln/precalciner/preheater conditions (e.g., temperature).…”

“…The enthalpy balance, hardly considered in LCI assessments, and variations in flue gas and stack (offgas) volumes and composition play a key role in plant operability (Tsiliyannis ; Ariyaratne et al. ) and emissions compliance, often under stricter limits than baseline. Capacity constraints and operability are also rarely considered in life cycle assessment (LCA) studies.…”

Improve the Compressive Strength Using a Strength Improver Agent (Sia) in the Cement Industry in Indonesia

“…However, clinker production involves burning limestone at high temperatures, which requires a significant amount of fuel [7,8]. This process leads to carbon emissions not only from the calcination reaction but also from the fuel combustion reaction in the kiln [9,10]. To address his issue, cement producers have been making efforts to reduce clinker by using alternative materials such as trass, slag, fly ash, etc.…”

CFD Modeling of Multi-fuel Combustion of Coal and Meat and Bone Meal (MBM) in a Cement Rotary Kiln

“…This is a pure biofuel and hence more attractive as an environmentally friendly fuel. In a previous modeling study carried out by the authors of the current study, it was found that the kiln gas flow rate is higher and the kiln gas temperature is lower for MBM than for several other solid waste-derived fuels, when replacing 100% of the coal energy in the cement rotary kiln [3], [8]. A full-scale cement kiln test also demonstrated the negative effects of burning high amounts of MBM [9].…”

“…This fuel is prepared by grinding and sterilizing slaughter house wastes [8]. This is a pure biofuel and hence more attractive as an environmentally friendly fuel.…”