WASTE HEAT RECOVERY DESIGN CONSIDERATIONS

Energy Distribution of Grate Cooler

  • The tertiary air flow is used as a source of energy for heating kiln feed at the pre-calciner (Air flow rate for pulverized coal heating can be ignored as low volume required).
  • The secondary air flow is required by the process system, which is high energy bearing air from the Kiln.
  • Total air flow required for cooling of clinker.

DOUBLE PRESSURE TECHNOLOGY

The double pressure technology allows for the generation of electricity using two different pressure lines (rated differently), however application of make-up burning technology has been found to cause disturbance to the cement production Line. Whether this Technology can be adopted or not shall be with the consideration of the price ratio of electricity over coal.

Process:

The make up steam is supplied to the opening in the middle of steam turbine and works together with main steam. In theory if the make up steam is supplied stable, the low temperature waste heat can be utilized as well, which means that the waste heat utilization can be higher and increase efficiency.

FLOW CHART OF DOUBLE PRESSURE SYSTEM

ADVANTAGES / DIS-ADVANTAGES OF DOUBLE PRESSURE TECHNOLOGY

DOUBLE PRESSURE AT OUTLET OF KILN (COOLER)

Parameters

  • Main steam: 7 – 13 kg/cm2
  • Make up steam: 1 – 5 kg/cm2

Features

  • Main steam slightly superheated.
  • There are two openings for steam turbine

Problems

  • Clinker feeding from kiln features the fluctuation and intermittent as well as interruption.
  • Currently there are 50 double pressure lines in China, but only about 30% of operation time requires make-up steam

Disadvantages

  • Frequent operation of make-up steam can cause faults and other problems.
  • Operation always waived for make-up steam.

WASTE HEAT RECOVERY (WHR) DESIGN PRINCIPLES

WHR power plant should not influence the normal operation of the clinker production line, including the output, quality and energy consumption etc.

Chinese systems and equipment used for WHR power plant have been proven to be reliable.

The existing equipment facilities and the waste heat are made full use as much as possible. A turbojet turbine with rated capacity of 7.5MW is designed for the 3100TPD clinker production line.

The waste heat from cooler at kiln outlet and preheat at kiln inlet of the cement production line will be made full use. One extraction duct is designed in the middle section of cooler.

Primary reverse osmosis treatment is used for supplementary water of boilers for good water management. And chemical treatment water workshop is located in the turbojet workshop to save area occupation.

Mechanical cooling tower with steel and concrete structure is installed for circulation water system.

One thermal deaerator is installed for feeding water in the process of deoxidizing with non-adjustable steam.

The 505 micro-electro-hydraulic system is installed for thermodynamic automation section

Ready for the next step?

 

SUBSCRIBE TO NEWSLETTER

 
 
 
 

CONTACT US

+27 (0) 16 421-3720
+27 (0) 16 422-1038
info@dgrp.co.za

 

ADDRESS

10 Smuts Ave, Vereeniging
Gauteng, 1930
South Africa