Ref: P.ppt (17/09/2015) 1 EUROTHERM a bc 2704 Application Cross Limiting Control

Ref: P.ppt (17/09/2015) 2 EUROTHERM a bc What is it ? Control of Fuel Air mixture. Ratio control. Lead Lag control. –Air leads on ramp up –Gas leads on ramp down

Ref: P.ppt (17/09/2015) 3 EUROTHERM a bc Why is it used Avoids dangerous mixture Improved combustion efficiency Profiled Temperature

Ref: P.ppt (17/09/2015) 4 EUROTHERM a bc Why 2704 Application was on rotary kiln. –Price. Always helps. Half alternative unit –Display. Temperature profiling was an advantage. The original idea was to use 2604 –Flexibility Upgrading from a single 904 temperature loop with manual control of flow valves allowed redirect of output to gas valve to initially run the same way.

Ref: P.ppt (17/09/2015) 5 EUROTHERM a bc How is it implemented on 2704

Ref: P.ppt (17/09/2015) 6 EUROTHERM a bc How is it implemented on 2704 Cross Limit Control –Never gas rich –Valve low limit 25%

Ref: P.ppt (17/09/2015) 7 EUROTHERM a bc How is it implemented on 2704 Ratio Setpoint Ratio=RatioSP(1+ExcessAir/100) Excess air in % Fixed value or output of Loop from Oxygen analyser

Ref: P.ppt (17/09/2015) 8 EUROTHERM a bc How is it implemented on 2704 Local Remote –Both in remote, follow demand. –Gas in local, Air follows gas –Air in local, Gas follows air –If either in local demand tracks gas flow –Manual in % from demand or in flow units from local

Ref: P.ppt (17/09/2015) 9 EUROTHERM a bc How is it implemented on 2704 Scaling Temperature OP to Gas flow % to m 3 /hr Use Gas Range_High Fuel flow to Air Flow Kg/hr to m 3 /hr Use Stoichiometric value

Ref: P.ppt (17/09/2015) 10 EUROTHERM a bc Stoichiometry “A €5 idea with a €50 name” Deals with the calculations about masses (sometimes volumes) of reactants and products involved in a chemical reaction –CH 4 + 2O 2 = CO 2 + 2H 2 O Dervied from Greek words –Stoicheion meaning Element –Metron meaning Measure Principles by Jeremias Benjamin Richter in 1792

Ref: P.ppt (17/09/2015) 11 EUROTHERM a bc How is it implemented on 2704 Alarms –Low alarm from loop block. Inhibits input to kiln –Ratio high and low alarms, from User_Alarms block.

Ref: P.ppt (17/09/2015) 12 EUROTHERM a bc How is it implemented on 2704 Summary Display –List of prime operating parameters

Ref: P.ppt (17/09/2015) 13 EUROTHERM a bc How is it implemented on 2704 Loop Display –Main operating parameters added to loop pages