8/10/2019 Cement Kiln Cogeneration

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Cement kiln cogeneration

Some of the waste heat generated in rotary kilns may bereused to preheat raw materials but a significant quantity is

lost. To reduce the amount of heat loss and maximise the

energy potential of the fuel used in kilns, the excess waste

heat can be redirected into a generation plant to produce

electricity for reuse within the plant.

Cogeneration in cement plants

The installation of electricity generation facilities in cement

plants is not a new practice. Asia–Pacific Partnership

(APP) countries such as Japan, China and India areinstalling these units in greater numbers to improve the

overall efficiency in energy conversion and to capitalise on

potential cost and energy savings and (for China and India

in particular) clean development incentives.

China in particular is installing smaller scale plants

to capitalise on the waste heat potential. Unlike other

cogeneration systems in which process steam and

electricity are produced simultaneously, these plants are

commonly referred as ‘bottoming cycle’ plants in that they

scavenge the available waste heat to produce electricity.

Cogeneration demonstration project

The demonstration project is designed to test the feasibility

of installing suitable cogeneration technologies in cement

plants in Australia.

An Australian company, Boral Limited, volunteered one of

its plants in Berrima NSW to be the test site for the project.

A feasibility study will examine the technical and financial

options for installing a plant including such considerations

as connection to existing plant, energy and greenhouse gas

savings and the implications on other factors such as water

use. If the project appears feasible, the study will also carry

out preliminary scoping for a business case to assist the

company in the implementation of the project.

At the time of writing (August 2007), a consultant has been

appointed to carry out the feasibility study.

Project support

The project is jointly supported by Boral Pty Ltd and the

Australian Government. The project is a demonstration project

for the Asia–Pacific Partnership on Clean Development andClimate (AP6).

AP6 is a ground-breaking climate change approach

bringing together key developed and developing countries

on practical, pro-growth, technology-driven efforts.

The Australian Government has committed

$100 million to support projects within the

AP6 framework.

Cement production is an energy intensive process. Energy in the form of electricity is used

to power various drive motors to run various systems such as mills, crushers, fans and

conveyors. However, the greatest energy use is in the production of heat for the pre-treatment

of raw materials and the combining of raw materials into clinker in the kiln section of the

cement plant. Kiln temperatures in rotary kilns, for example, may be 1500°C or higher and

fossil fuels such as coal, gas or oil are typically burnt to achieve those temperatures.

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