Raw Grinding Ball Mill Interlocks-v0.0.xls

RAW GRINDING BALL MILL - CONTROL LOOPS V0.0 Controlled Parameter

Actuator

Target

DATA TO BE FILLED BY PLANTS Comments

Total mill feed (Fresh feed + separator rejects) or elevator power

Fresh Feed Weigh feeders

Optimized production and power consumption

To provide constant material flow through the mill, target mill throughput is given by operator in t/h

Separator Gas Flow

Raw Mill fan Variable Speed Drive or adjustable Damper

Consistent particle size distribution

Constant gas flow through the separator ensures constant lift of material and separator performance constant, gas flow measurement by venturi before mill fan, pressure loss across the mill cyclones can also be used.

Mill Outlet Gas Temperature

Inlet damper, bypass damper, second Adequate drying of raw material and to compartment water injection or Hot protect mill bearing and separator gas generator damper/fan speed

Mill Inlet static Pressure

Recirculation Damper

Optimization of pressure load on fan

Fineness Final Product

Separator Variable Speed Drive

Constant product fineness

Air flow through the separator must be maintained constant to achieve constant product fineness at the same speed

Raw Meal Chemistry

Proportions of Raw Mill Feed and corrective material

Consistent quality results

QMC can be used to control the proportions of corrective material according to quality results

Hot Gas Generator Outlet Gas Temperature

Fuel Amount

To maintain the target HAG

Outlet gas temperature is automatically controlled by controlling the fuel flow rate.

Excessively high temperatures affect bearings of mill & separator and performance of a downstream electro-static precipitator (if fitted). Outlet temperature should be controlled by hot gas/ recycle gas flow.

Control Loop Available in PCS (Y/N)

Control Loop in Auto/Manual

Reason for run in Manual Mode

Comments [if any]

RAW GRINDING BALL MILL - ESSENTIAL PROCESS INTERLOCKS V0.0 Process Group

Hoppers Feeding

Mill Inlet Damper

Raw Mill Feed

Source of condition

Stop Condition

Delay for stop [seconds]*

Raw Meal Feed Bin Level Corrective Material 1 Feed Bin Level Corrective Material 2 Feed Bin Level Raw Meal Feed Bin digital Level Sensor


> HH > HH > HH Activated

3 3 3 3

Avoid overfilling Avoid overfilling Avoid overfilling Avoid overfilling

Corrective Material 1 Feed Bin digital Level Sensor

Not activated

Activated

3

Avoid overfilling

Corrective Material 2 Feed Bin digital Level Sensor

Not activated

Activated

3

Avoid overfilling

> HH

5*60

< LL < LL > HH HH OFF

N/A 3 3 3 3 3 5*60

Deviation

5*60

Raw Mill Outlet Gas Temperature Raw Mill Outlet Gas Temperature Raw Mill Sound Level Raw Mill Power Homo Silo Level Hopper Level Elevator boot level Weigh Feeders

>L

>L
Weigh Feeder's Deviation Raw Mill Main Drive

Mill Outlet Elevator power

Mill Filter Hopper Level Sensor

Hot Gas Generator Outlet pressure

Note:-

Avoid overfilling of mill 1st chamber. (Raw mill main drive stops mill feeding stop) >10 mbar

3 60

>H >H Not activated

Activated

5*60

Trip Mill Filter Fan. If the mill has its own filter

>HH

3

Trip Mill Filter Fan. If the mill has its own filter

>HH

3

Trip Mill Filter Fan. If the mill has its own filter

OFF
Enabled Temperature Deadband to be fixed by plant Ensure correct silo is selected Avoid overfilling of homo silo For protecting the mill bearing and separator

To avoid HGG backfiring

Mill filter outlet pressure

*Delay for stop:-

Avoid empty running of mill and damage to liners 5% Deviation in weigh feeders. To avoid quality deviations and empty run of mill. Need to to be set in weigh feeder controller

>HH Stopped or Minimum Speed Closed OFF
Mill Filter & Fan (Normally with Mill Filter DP/Filter Outlet Pressure Pyro system)

Mill Second Compartment Water Mill feed Spraying Mill Outlet Gas Temperature Silo Selection for Product Raw Meal Transport/Others Homo Silo Level Hot Gas Generator Outlet Gas Temperature Raw Mill Outlet Gas Temperature Hot Gas Generator Control Unit Raw Mill Inlet Gas Temperature

Close damper for separator and mill bearing protection, Mill must be heated up properly before giving feed Avoid overfilling of the mill. Avoid overfilling of the mill. Avoid overfilling of homo silo

>HH

Kiln ID Fan Kiln ID fan Damper Kiln Filter Fan Raw Mill Outlet Gas Temperature Raw Mill Inlet Gas Temperature

Comments


Kiln Fan Outlet Pressure

Inlet Fresh Air Damper

DATA TO BE FILLED BY PLANT

Start Condition

ON >L ON

3 3 3 3 3


> HH > HH > HH > HH

3 3 3 3 3 3 3

Negative

Positive

3

3 seconds is proposed in order to avoid stoppage due to signal perturbation (can be increased/reduced according to site conditions) In general, delays can be adjusted according to site conditions/circuit configuration/OEM recommendation. Some limit values mentioned in comments are for ultimate safety. Operational limits needs to be set based on supplier/OEM recommendation or circuit configuration.

Open damper for separator protection Open damper for protecting the mill bearing

Interlock Available in PCS (Y/N)

Value of Start Condition

Value of Stop Condition

Values of Alarm Limits

Sensor Operating Range Min Value

Sensor Operating Range Max Value

Existing Delay for Stop Interlock Active [Seconds] /Bypass

Reason for Bypass

Comments [if any]