4,300 TPD Cement Production Line WHR System

March , 2021 China

1 General Description
1.1 Basic Condition
1.1.1 Basic Condition of Clinker production line
Mechanical
 Preheater
Number of stage in line 4,300 TPD: 6
 Kiln
Line 4,300 TPD:
Type: Rotary kiln
1.2 Design Principle of WHR system
1.2.1 Design Condition
Clinker production line:
Throughput: 4,300 T/D
Exhausted gas parameter (utilized for power generation)
Cooler Exhausted gas volume: 210,000Nm3/h
The designed inlet gas volume of the AQC Boiler: 210,000Nm3/h
Exhausted gas temperature: 450�?br/>The designed inlet gas(used as the waste heat) temperature of the AQC boiler: 450�?br/>Gas temperature at outlet of boiler: 100�?br/>Pre-heater Exhausted gas volume: 280,000 Nm3/h
The designed inlet gas volume of the SP boiler: 280,000 Nm3/h
Exhausted gas temperature: 260�?br/>Designed inlet gas temperature of SP boiler: 260�?br/>Gas temperature at outlet of boiler: 210�?br/>Output of WHR system under above conditions are as follows:
Average gross output: 5.950 MW
The installed capacity is 6MW.
1.2.2 Summary Description Of WHR System And Main Equipment
The WHR system consists of Thermal system, Water supply and drainage system, Chemical water
treatment system, Air cooling system, Electric system, I &C system, MVAC system.
According to the cement line waste heat parameters 4300t/d cement lines based on waste heat
parameters set AQC boiler, SP boiler.
2Main equipment of Thermal system are 2 units of boilers, 1 unit of turbine and 1 unit of generator
(under the design condition):
AQC boiler, 1 unit.
Total flow of vapor 35.2t/h, pressure, 1.25 MPa(a), temperature, 350�?
The AQC boiler’s saturated steam section is 26.4 t/h, pressure, 1.25 MPa(a), temperature,194�?br/>SP boiler, 1 unit.
Flow of vapour,8.8 t/h, pressure, 1.25 MPa(a), temperature,194�?br/>Turbine: 1 unit, model No. N6-1.15(340�?, condensing type, rated output 6MW.
Generator: 1 unit, model No. QF-J6-2, rated output 6MW.
1.2.3 WHR System General Layout Principle and Summary Description
The AQC boilers is designed between the exhausted gas outlet in the tail of cooler and the cooler
ESP ,using cooler duct as gas discharging duct for AQC. When the AQC boiler is running , by
adjusting close-open percent of AQC boiler by-pass valve , to control AQC boiler exhaust
temperature imports. When the AQC boiler in an accident, inlet and outlet valve of AQC boiler are
both closed, AQC boiler by-pass valve open to the biggest degree, the cooler rear waste gas exhaust
all by by-pass valve.
SP boiler take gas from pre-heater rear, the water tower exhaust pipes as a bypass, exhaust duct of
SP boiler have two ways, and the in-out duct of boiler SP set valve (one valve per export branch)
for bypass. When SP boiler normal run ,the bypass valve full off; When the SP boiler in an accident
or SP boiler outlet exhaust temperature need to be adjusted, the bypass valve open. The kiln end
waste gas pass through waste heat boiler, then used for raw material grinding and drying. In SP
boiler failure, waste gas can be directly taken by by-pass way of SP boiler for the raw mill.
After waste gas of kiln head and kiln end heat exchange in waste heat boiler, settling down kiln
dust.
AQC boiler 8t/h
SP boiler 25t/h
The main block consisting of Turbine house, CCR, MV/LV substation, chemical water treatment
system cover area 32×15 m2.
Double-deck layout turbo-generator, ±0.000 plant for auxiliary equipment, boiler feed pumps,
condensers, condensate pumps; for operating layer at 7.500m plant, turbine and generator layout in
this plan, oil supply system at 3.500m plant. For ease of maintenance, the turbine room within the
slow overhead traveling crane 1pes, LK = 13.5m, weights 16t,single supply, rail-to-top height
15.000m.The electrical room is arranged on the side of the turbine room, 0.000m is the electrical
room, and 7.500m is the control room. Deaerator layout above the control room.
The chemical water treatment plant is located near the side of the turbine generator house.
Chemical water treatment plant are close to the turbo-generator room side. Water tanks layout in
the top of chemical water treatment plant.
AQC boiler layout in cement production plant on one side of the kiln head house, the occupying a
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land area of about 20×10m2, boiler adopt the outdoor layout 4.500 plant layout kiln head waste heat
boiler, Dosing device, steam sample system, and so on installment in ±0.000 the plant.
SP boiler arrangement on the side of pre-heater frame of cement production line, SP boiler
occupying land area approximately for 15×12m2, the boiler adopt the outdoor layout. 16.000 plant
layout kiln end waste heat boiler, converting kiln dust system, steam sample system, the pollution
discharge sets, and so on installment in ±0.000 the plant.
Air-cooling island station occupying land area 18×16m2.
2 Code and Standard
Chinese code and standard for design, material, fabrication, test and inspection, packing, erection,
commissioning and performance test shall be applied.
3 System Description
3.1 Thermal System
3.1.1 System Description
According to the temperature distribution of cement production line cooler exhaust emissions meet
the premise of the clinker cooling and process heat, AQC boiler take the tail of the cooler to take wind
increases the heat transfer at the same time to reduce the volume of AQC boiler, and improve the
cycle thermal efficiency of the entire system. Vertical boilers, waste heat boilers reduce floor space,
reduce air leakage, increase heat recovery.
AQC boiler is equipped with steam generate steam superheated and economizer, economizer segment
is divided into two sections with high temperature, low temperature.
Hot water generated in economizer section of AQC boiler is supplied to AQC and SP boilers
respectively, to produces the main steam. SP boiler’s steam return to the AQC boiler to generate
superheat steam.
Superheated steam of cement kiln waste heat boiler come into the steam room as the main steam into
the turbine, power generation is done 5950 kW. The steam after working through the condenser
change into 54�?water, through condensate pumps pump into cement line AQC boiler economizer. It
forms a complete heating cycle.
According to the steam quantity produced, the steam turbine selected type is N6-1.15.
Above these, helping power station operates flexible, reliable, be well and mix cement production.
3.1.2 MVAC System Description
3.1.2.1 Ventilation
Mechanical ventilation shall be adopted in the chemical water treatment workshop, turbine house,
MV/LV substation. Natural ventilation is adopted for other departments.
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3.1.2.2 Air conditioning
The cold/warm air conditioner is adopted in CCR room to satisfy the requirement of room
temperature 20±3�?
3.2 Cooling System
3.2.1 Circulating Water System
3.2.1.1 Cooling Water Flow
The cooling water quantity is as follows:
 Cooling water for oil cooler: 80 m3 /h
 Cooling water for air cooler: 80 m3 /h
 Cooling water for the feeding water pump and boiler sampling: 1 m3 /h
 Total: 161 m3/h
3.2.1.2 Flow Chart of Cooling Water System
Water circulation is adopted for the system. The system consists of circulating water pump, cooling
tower and circulation piping system. Water from collect water dish are transport to every workshop by
water pump for cooling purpose, and after usage return to cooling tower by circulating pump and then
back the water dish. The water is recycled, necessary dosing and waste water discharging is design to
guarantee the operation of the system.
3.2.1.3 Type of Main Equipment
Based on the site condition, the following type of equipment are adopted:
2 sets of single stage centrifugal pump.
1 sets of mechanical ventilation type cooling tower. The temperature difference between inlet and
outlet of the cooling tower is 10�?.
3.2.2 Air Cooling System
3.2.2.1 System Description
In order to solve the problem of water resources shortage, this system use the air cooling condenser to
cool steam turbine exhaust. Air cooling power is not enough in summer,we need to peak cooling
device with cooling.
3.2.2.2 Flow Chart of Air Cooling System
Steam turbine exhaust –Air cooling system - Evaporative condenser (only used in
summer) –Condensate pump –deaerator- Back to the waste heat boiler to use
3.2.2.3 Allocation Plan
Air cooling island is divided into four units, covers an area of 18 mx16 m.
1 set of evaporative condenser, covers an area of 6.5 mx3.5 m.
3.2.3 Water Loss and Supplement Water Quantity
Water loss and supplement water quantity are as follows:
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 Evaporated and leakage quantity: 4 m3 /h
 System drainage: 0.4 m3 /h
 Total loss of water: 4.4 m3 /h
3.3 Chemical Water Treatment System
3.3.1 The Chemical Water Treatment Plan
Water treatment flow sheet is as follows: water from closed pipeline →raw water tank→raw water
pump →multi-mediator filter →active carbon filter �?5μm filter →high pressure pump�?reverse
osmosis device �?Intermediate water tank �?Intermediate water pump→Water softening plant
→demineralized Water Tank �?demineralized Water pump �?user. Outlet water quality attains:
hardness should be less than 2 μmol/L.
To prevent the corrosion to the equipment of thermal system by the dissolved oxygen, oxygen content
of boiler shall be controlled by heating deaerating. There is Vacuum deaerator, after deoxygenize of
the demineralized water, the oxygen content is less than 0.05mg/l. The water quality control of boiler
drum are realized by dosing method by Na3PO4ꞏ12H2O dissolved water by dosing pump.
3.3.2 Arrangement of the System
The system consists of water treatment room and laboratory are located inside the main block with
total area of 7.5×16.5m. Water tanks layout in the top of chemical water treatment plant.
3.4 Electrical System
3.4.1 System Description
The electrical system consists of Power connection system, Substation, Lighting and earthing system.
3.4.1.1 Power Connection System
To guarantee the reliable operation WHR system, the MV/LV substation will be designed along the
side of turbine house.
The voltage of power generated by generator is 6.3KV. The power will be connected to the inlet of
connection cabinet of 6.3KV bus bar by single circuit connection. Synchronizing control is on the
WHR system side, the connection point on the GCB and interconnection tie circuit breaker side. The
power generated by WHR system will not be transported to the grid.
Power connection system shall be design and supply by the Owner based on the requirement of local
authority.
3.4.1.2 Substation
Substation consists of main connection and distribution system,, auxiliary transformer, electrical room
and necessary protection and measurement device.
3.4.1.2.1 Main Connection and Distribution System
For detail, please refer to Single-Line Diagram. The 6.3KV bus bar shall be single line without
separation.
Main power supply: 6.3kV, 50Hz
Emergency power supply: 0.4kV, 50Hz
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MV distribution: 6.3 kV
MV motor: 6.3 kV
DC panel power: 11 0V DC
LV distribution: 0.4kV
LV motor: 0.4kV
Lighting system: 230VAC
Control power: 230 VAC/24VDC
Maintenance lighting system: 24V/12V
3.4.1.2.2 DC and UPS System
The MV service power of the WHR system is DC. The dual loop DC system is designed for a voltage
of 110V.
3.4.1.2.3 Type of Equipment
6.3KV cabinet: indoor, AC, MV Mid type switchgear cabinet.
MV breaker: vacuum breaker
LV MCC: fixed type
Control and protection system: micro-computer multi functional automation system
3.4.1.2.4 The Transformer and Electric Room
Auxiliary transformer is dry type, SCB series. Auxiliary machine power for WHR system will be�?%.
3.4.1.2.4.1 Main load
According to the station electricity load calculation results, taking into account the economic plant
operation and reliability, the substation transformer configuration for transformer power station 6.3
kV bus configuration, the model for the SC(B)10-800-6.3/0.4~0.23.
3.4.1.3 Lighting System
1) Lighting for normal operation
The power supply for lighting system for normal operation of WHR system is from the electric room,
the voltage is 380/220V. The lighting is realized by the combination of completed and part lighting.
There are power leakage protection switch of the light (active current is 30mA)
2) Accident lighting system
Power supply for accident lighting is from DC system automatically when all the AC power
disappears. Subject to the importance of different location, accident lighting are designed at the
entrance of the main block, passage, stair well, MV/LV substation, CCR. Accident lighting system is
separated from lighting for normal operation.
3) Safety lighting system
During the maintenance of boiler and other metal body equipment, safety portable lighting shall be
adopted with 12VAC safety power supply.
3.4.1.4 Lightning and Earthing System
TN-C-S standard is adopted.
The earthing system of boilers is to be connected to the existing earthing system.
DCS system is to be grounded separately and the earthing resistance is less than 1 .
3.5 I & C System
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3.5.1 System Description
3.5.1.1 Principle for Design
Centralized priority control mode (hereinafter called CCR) is adopted for boiler, turbine and generator.
The operation/monitoring/management of boiler, turbine, generator, circulation cooling water system
and chemical water treatment system are realized in CCR.
Local priority is adopted for DCS system. Control cabinet at site has the choice of remote, local and
off. The control box is locked by uniformed key.
When at Remote control, the motor, motorized valve and other equipments will be operated by the
operator in CCR based on the system and equipment operation requirement. The start and stop shall
be operated by the logic order. The ready, run, fault status is showed on the LED display. All
fault/alarm status can also be printed out.
When at Local control, the start and stop can be realized at site, for the individual equipment
commissioning.
When at off, neither CCR nor site can operate the equipment for safety purpose.
When at fault status, both in CCR and at site can stop the equipment for safety purpose.
The function of automatically generation report will be implemented in the DCS system.
3.5.1.2 Type of I & C Equipment
DCS system are adopted for process data collection, monitoring, alarm and control.
Pressure / pressure difference transmitter
Temperature monitor transmitter
Boiler drum water level monitoring system:
3.5.1.3 CCTV industrial monitor system
Video surveillance system needs to consider the second phase video surveillance system.
3.5.1.4 Function of the System
The DCS system is consist of site and CCR control.
Site control
I/O modular unit is designed inside CCR, to collect all the switch and analog signal and send driving
signal.
Site control will carried out motor sequence logical control, process the parameter monitor and control
etc.
CCR
CCR has 1 engineer station and 5 monitor/operation stations, which consisting of monitor/operation
computer, LED and printer. The monitor/operation station has the following faction:
- Dynamic parameter of the thermal system and process flow sheet display
- Motor start / stop operation and working status display
- Stick drawing display
- Historical trend display
- Adjusting loop detailed display and parameter adjustment
- Alarm status display
- Printing of alarm status and working status
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4 Civil Works
4.1 Typical Foundation Type (Underground and Equipment)
4.1.1 Underground Foundation
According to the geographic condition listed, the type of underground foundation are:
Complete concrete foundation for main block, boiler, and circulation cooling water pool.
4.1.2 Equipment Foundation
Reinforced concrete structure for generator and turbine foundation.
Concrete structure for boiler foundation.
4.2 Typical Building and Structure
Structure type
Multiple platform building: reinforced concrete structure for main block (including turbine house
and CCR) and boiler.
Single platform workshop: brick and concrete structure for water pump station.
Description of inside structure
Roof: Reinforced concrete type/ Steel structure, to match the existing building of cement plant, the
roof WHR system building also adopt organized drainage. In case of reinforced concrete roof SBS
water proof material shall be applied outside, in case of steel structure roof shaped steel plate are
applied.
Wall: Framework filling wall adopts local lightweight brick, common brick shall be applied for
load wall with main support of brick and concrete structure. Main block (including turbine house
and CCR) have high requirement of fireproofing, riot proofing, noise proofing. CCR and turbine
house are divided by common fire proof brick or middle-vacuumed fire proof glass. Stairway are
concrete and re separated by common fire proof brick. Ground, floor: cement slurry layer or
concrete or ground brick.
Door and window: steel type, aluminum alloy or plastic material type. Anti noise and/or fire proof
type if necessary. For better lighting, anti-explosive and ventilation, big size steel window are applied
for turbine house. Anti-fire window and door (2Hours resistance) are adopted for CCR.
Stairway and ladder: reinforced concrete or steel stair type. Steel pipe are adopted as protection
handrail.
Surface of inside and outside of wall: The outside wall shall be stuccoed. The inside door can be
stuccoed or printed by slurry.