China National Electric Wire & Cable Imp./Exp. Corp.

The Technical Solution Of Low Temperature Waste Heat Power Plant of 7.5MW

 For 2x2500t/d Cement Production Line

 

Take consideration of the process flow, layout, power supply and distribution, and water supply of the clinker production lines, by utilizing the heat resource exhausted from the pre heater and cooler, one 7500kw pure low temperature waste heat power station is appropriate for the 2*2500t/d clinker production line.

 

1. Waste heat resource

The waste heat source of the cement line can be utilized as follows:

2*2500t/d cement production lines kiln outlet cooler waste heat condition after reformation will be 2*65000Nm³/h-350 C. Degree .The waste gas will be introduced into the kiln outlet waste heat boiler(AQC boiler) for power generation; Outlet waste gas of the AQC boiler will be introduced into the existing kiln outlet EP.

Kiln inlet five-stage pre heater waste gas condition will be 2*150000Nm³/h-340 C Degree

The waste gas will be introduced into the kiln inlet waste heat boiler (SP boiler) for power generation and the exhausted gas temperature should be higher than 220℃for raw mill or coal mill drying.

 

2. Power supply and connection system solution

At the beginning of the power station putting into production, 300~500kw start-up power supply is necessary which will be supplied by the general substation. After the generation putting into production, the generator will be connected to outside power network by general substation 6(10) kV. The power station and the existing system will be connected to the outside power network, but not feed power to it. The power consumption of the station will be supplied general substation or generator.

 

In order to make sure the power station run in reason and smoothly, a high & low voltage distribution room should be plotted on the side of the main building.

As the waste heat power station of the company, the generation power should be fed to the cement production line. The power station and the existing system will be connected to outside power network, but not feed power to it. Connection synchronous points will be set at generation liaison switch and generator outlet switch.

 

3. Water supply

Since the average production and domestic water consumption will be about 1800m³/d, the water supply capacity should be 2200m³/d.

 

Technical safeguard condition

 

Thermodynamic system

According to the process flow and design parameter of 2*2500t/d cement production lines, adopting China institutes and manufacturers pure low temperature waste heat recovery technique and Chinese made equipments, the power generation amount per ton clinker can achieve 36~38kwh..

 

Brief introduction of technical solution

 

Two kiln outlet waste heat boilers-AQC boilers

The AQC boiler is arranged between cooler middle stage and the existing kiln outlet EP. The heat-receiving surface of the AQC boiler is divided into two stages: the first stage produces steam, and the second stage produces hot water. The saturation water of 135ℿwill be feed to the AQC boiler steam stage and kiln inlet waste heat boiler(hereinafter called SP boiler); 1.6 MPa superheated steam produced in AQC boiler steam stage and SP boiler merges together and is introduced to a turbine for power generation. Condensing water of the turbine is pumped to AQC boiler hot water stage..

 

Two kiln inlet waste heat boilers-SP boilers

The SP boiler is at the outlet of pre heater. The superheated steam produced in SP boiler and AQC boiler steam stage merges together and is introduced to a turbine foe power generation.

 

One condensing steam turbine is adopted to match the low temperature waste heat power station

A Chinese-made condensing steam turbine is adopted, rated power is 4500kw, and initial steam parameter is 1.27Mpa-290 C. Degree

 

One generator os selected to match the condensing turbine

One normal 6(10)kv AC generator with 7500kw rated power is adopted, which will be connected to outside power network by general substation 6(10)kv.

 

Circulation cooling water system will be adopted for meeting the cooling water demand of the power station.

 

4.2.6A"Filter+demineralizing" system is adopted as chemical water treatment for meeting the boiler water criterion.

 

DCS computer control system is adopted for monitoring the power station sunning.

 

4.3 Main equipment

No	Equipment name and model	Quantity	Main technical spec.
1	Condensing steam turbine	1	Rated power: 7.5MW Initial steam pressure: 1.27MPa Initial steam temperature: 290
2	generator	1	Rated power: 7.5MW Outgoing voltage: 6300V(10500V)
3	Kiln inlet waste heat boiler(P boiler)	2	Inlet gas amount: 150000Nm3/h Inlet gas temperature: 340 Outlet gas temperature: 250
4	Kiln outlet waste heat boiler(AQC boiler)	2	Inlet gas amount: 65000Nm3/h Inlet gas temperature: 350> Outlet gas temperature: 100

Main Economical Data and Index

No.	Technical designation	Unit	Indexes	Remarks
1	Installed capacity	MW	7.5
2	Average generation power	MW	8.0
3	Annual power generation	103kwh	58000
4	Annual water consumption	103t/a	About300
5	Per ton clinker waste heat power generation amount	Kwh/t	36~38
6	Average generation power cost	RMB/kwh	0.10~0.15
7	Total investment	Million RMB	55-60
8	Investment recovery period	Year	2.5~3

Investment is only for theoritical calculation, quotation will be to individual project.