Investigation of using kalian cycle for waste heat recovery in a cement plant

Abstract EN

The cement industry is considered one of the most energy intensive industrial processes in the world.

The energy cost average is about 55% of the total cost of cement production.

Massive energy cost is due to both heat consumption in kiln operations and electrical power consumption for different operations of grinding mills, fans, and motors.

Waste heat recovery is a way to reduce the total power consumption for the cement production process by using a heat recovery system to generate electrical energy with no more fuel or electrical power consumption.

In a typical cement plant, 25% of the total energy is electrical energy, and 75% is thermal energy.

About 35-40% of the total process heat is lost through waste heat streams.

In a cement plant, 26% of heat input is lost through the kiln, preheater surfaces, convection from the kiln, and preheaters.

This article reports on waste heat recovery from a typical cement plant in Egypt.

Measurements and analyses have been performed to determine the waste heat from different stages of the cement manufacturing lines.

The annual heat losses from the kiln surface, preheater, and the cooler are estimated as 79.23, 44.32, and 43.6 GWh at average temperatures of about 314, 314, and 254℃, respectively.

Analysis and optimization of using the Kalina cycle for Waste Heat Recovery (WHR) from the kiln shell, cooler, and preheater to produce electricity have been carried out using ASPEN software.

A parametric study has been carried out to determine the design parameters for the Kalina cycle including turbine inlet pressure, mass flow rate, and ammonia water concentration.

Two design alternatives have been investigated using separate and combined WHR from the kiln, cooler, and preheater.

The value of net power output using combined WHR is about 7.35 MW as compared to 6.86 using a separate WHR design with a total cost saving of about 23% .