Vietnam is currently the leading country in cement production in Asia with a cement production output of 63 million tons in 2010 and more than 60 dry kiln cement lines built. However, Vietnam's cement industry is currently facing major challenges such as the price of electricity, coal and oil continuously increasing, affecting the company's production and business efficiency. At the same time, emissions and waste heat are also a concern for industries that cause serious environmental pollution such as cement. Therefore, taking advantage of excess heat in cement kilns to generate electricity is a practical and meaningful job for cement plants.

1. What is a residual heat removal system?
The residual heat removal system is a system that uses the excess heat of the cement plant to generate electricity. The purpose is to save heat loss thanks to this system. This system can be compared basically to a thermal power plant with the initial heat source taking advantage of the residual heat of the cement plant.
In recent years, many cement companies around the world have taken advantage of the waste heat of clinker kilns to generate electricity, self-sufficient in nearly 30% of the electricity demand for cement production, and at the same time have made an important contribution to the minimizing environmental pollution, greenhouse effect, is the optimal solution.

2. Working principle:
- Hot wind with high temperature of 300-500oC comes out of the clinker cooler after passing through the separator, high efficiency is led to the residual heat boiler at the top of the kiln (AQC boiler) and then led into the system. furnace exhaust gas. Dust collected from the dust collector and AQC boiler is put into the kiln head clinker transport system
- High temperature 350 - 380oC flue gas from the furnace tail heat exchanger tower is led to the tail end boiler (SP boiler). The exhaust gas from the boiler at a low temperature of 250oC is directed to the dryer, crushing raw materials. The dust recovered from the furnace tail boiler will be sent to the kiln's dust transmission system
- The heat-receiving surface of the AQC boiler is divided into two stages, phase I is the stage that produces steam, and phase II is the stage that produces hot water. Saturated water at the temperature of 135oC generated by the boiler will be supplied to phase I of AQC boiler and to SP boiler, 1.6 MPa - 300oC superheated steam produced by phase I of AQC boiler will is the main steam, after combining with superheated steam with the same parameters generated by the SP boiler, it will enter the steam turbine.
- Using superheated steam to drive the turbine to drive the generator. The steam then passes through the condenser to condense, the condensate will be pumped back into the hot water stage of the AQC boiler, after heating, the water will be supplied to the boiler.
The generator is a common type of alternator. Through the 6 (10) kV busbar of the total substation, the machine will operate strongly in parallel with the local circuit

3. The main equipment of the exhaust heat recovery system
On the basis of research and analysis, determine the thermal parameters of the clinker kiln, the volume of flue gas at the beginning and the end of the kiln, temperature, pressure, the amount of gas required for drying and grinding raw materials, supplying reliable technical parameters to build a power station, choose a scientific and accurate plan, select appropriate and synchronous equipment with appropriate capacity. Some of the main devices can be mentioned below:
1. AQC kiln head residual heat boiler to use clinker cooling plant exhaust gas
2. SP tail end heat boiler to use waste gas from heat exchange tower
3. Steam turbine suitable for power station.
4. Synchronous generator with steam turbine is an ordinary AC generator
5. Circulating cooling water system, meeting the cooling water demand of power stations
6. Equip with a chemical water treatment system including a series of two-stage filtration equipment to meet the water demand for boilers of the power station
7. Equip with a synchronous DCS computer control system to meet the operating needs of the power station
8. Equip with piping system to convey hot air from heat exchange tower to SP boiler, exhaust gas from clinker cooler to AQC boiler, system to conduct superheated steam to gas turbine, water supply system, road power transmission line
To learn more documents researched by Fortune about the operation of each device, please contact with us.