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29.09.20141
Possibilities to reduce energy consumption and CO2‐emissions of paintshop‐dryers
EUROCAR‐Presentation
Dipl.‐Ing. Olaf Neese (CVET)Dipl.‐Ing. Karl‐Heinz Dammeyer (CVET)Dipl.‐Ing. Lukasz Piech (CVET)Prof. Dr.‐Ing. Otto Carlowitz (TU Clausthal)
29.09.20142
Outline
1. Introduction
2. Use of energy in paint dryer systems in the automotive industry
3. Basic approaches to adjust the heat‐balance in existing paint dryer systems with Thermal exhaust air purification plant (thermal post‐combustion; germ.: TNV)
4. Evaluation of the energy‐saving‐potential
5. Load‐controlled volume flow adjustment (germ. LAVA)
6. Prospect
29.09.20143
Basic possibilities to decrease the use of process energy
enhancement: permanent reduction of energy consumptionoptimization: the optimum of the use of energy is defined, known
and can be (almost) achieved
Reduction of energy use with
A organizational /logistic measures
B enhancement or optimization of current processes
C implementation of new processes
immediate short and medium term long term
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energy savings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Outline
29.09.20144
Energy input of an automotive plant by main production steps
Observation:The paint shop has the highest energy demand
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Outline
29.09.20145
Paint shop carbonemissionsOutline
Question:Which possibilities are available to reduce the energy demand of already existing production lines?
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energy savings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.20146
Simplified flow sheet of a top coat paint drying system (example)
Exhaust heat usage Exhaust air pre‐heater in the thermal post combustion (3) Infrared zones with mixing chambers (not in new plants) Convection zones with circulation gas recuperators (4) Fresh air pre‐heating with recuperator (5)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.20147
Energy flow sheet of a top coat dryer in the dimensioned maximum load state
Energy demand only slightly variable, because of• TNV‐temperature has to be constant• Exhaust air (amount and temperature) constant• organic load in the exhaust air/gas low
TNV‐temperature: 750 °CExhaust air vol. flow: 10,000 m3/h load: 30 car bodies/h
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.20148
Causes of heat imbalances at dryer System
Nearly every dryer does not operate in its calculated maximum state
A. static imbalancetemperature of the clean gas at stack is permanently (too) high transmittance heat loss of the entire plant overestimated subsequent isolation addedmass of car bodies constantly smaller than dimensioned number of car bodies permanent smaller than dimensioned short heating times required (hence overdesigned)
B. dynamic imbalancetemperature of the clean gas at stack is temporarily (too) high production breaks and cleaning car bodies with significantly differing masses set up times errors in the operation procedure
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Outline
29.09.20149
Identified options to adjust the heat balance of a dryer
1. Energetically separation of dryer heating and waste air cleaningPrecondition: the exhaust gas cleaning process has a
very low energy demand (RTO, catalytic RTO, biological processes,…)
2. Increase of the waste gas preheating in the thermal oxidizer
3. Reduction of the temperature level in the thermal oxidizerand complementation of a catalytic or in‐line RTO‐step
4. Reduction of the exhaust air volume flow rate (LAVA)and compensation of the changed flow conditions of the dryer
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Outline
29.09.201410
1. Energetically separation of dryer heating and waste air cleaning
High investment costs if fitted subsequently
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
dryer
car bodies+SKID
solvent
freshair
freshair
fuel
parts
cleangas
(process)
cleangas
(RNV)
car bodies+SKID
29.09.201411
2. Increase of the waste gas pre‐heating in the TNV‐system
increase of V by 15 % from 60 % to 75 %: reduplication of the heat exchange area reduction of the fuel demand by approx. 40 %
heat exchange area
V
VWÜA
1
Abluftvorwärmgrad V
rela
tiver
Bre
nnst
offb
edar
f
Fläc
henv
erhä
ltnis
Wär
meü
bert
rage
r
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201412
3. Reduction of the TNV‐temperature leveland complementation of a catalytically step
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201413
4. Load controlled volume flowadjustment: LAVA
simultaneous reduction of waste and fresh air volume flow rate therefore smaller clean gas enthalpy flow and fuel demand caution: (limited) intervention in the flow balance of the dryer the solution was examined in detail within a research project
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201414
How to evaluate the savingspotential
Equipping the waste heat line and the TNV with temperature sensors (temperatures of waste air, clean air, circulation air and fresh air)
Affixing of pilot tubes to measure the volume flow rates Experimentally reduction of the waste air volume flow, measurement of the
resulting changes in the waste heat line Continuous recording of the measured data (approx. 14 days)
(temperatures, concentrations, volume flow rates) Derivation of the heat transfer characteristics from the dimensioning data
and measurement data, feeding in a mathematical model
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201415
Measurements to obtain the currentstate and implementation of LAVA
Outline
aim: obtaining the characteristically energy demand of the examined plant in different operational conditions
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201416
Measured clean gas temperatures in thewaste heat line of a top coat dryer
0
100
200
300
400
500
0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00
Messzeit
Tem
pera
tur [
°C]
T311_RG_W31ein T321_RG_W32ein T331_RG_W33ein T341_RG_W34einT351_RG_W35ein T361_RG_W36ein T365_RG_W36aus T201_AbL_TNVein
Lee
rlauf
Vol
llast
Mittlere Last (Produktionstag)
Auf
heiz
betr
ieb
16
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
idle state
full load
partial load state (production day)
time
tempe
rature
29.09.201417
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Air balance and natural gas demand of a top coat dryer at full load state
per hour per yearDemand natural gas: 1070 kW 7490 MWCosts natural gas: 43 €/h 300 T€/a (0.04 €/kWh)CO2‐emissions: 257 kg/h 1800 t/a (0.24 kg/kWh)
production: 7000 h/a
load: 27 car bodies/hcirc. gas
circ. gas
circ. gas
circ. gas
waste air
waste air
clean gas
clean gas
fresh air
29.09.201418
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Energy savings potential with LAVA is up to 20 % at full load state
operation effort/h saving/h saving/aDemand natural gas: 850 kW 220 kW 1540 MWCosts natural gas: 34 €/h 9 €/h 63,000 €/aCO2‐emissions: 204 kg/h 53 kg/h 371 t/a
production: 7000 h/aload: 27 car bodies/hcirc. gas
circ. gas
circ. gas
circ. gas
waste air
waste air
clean gas
clean gas
fresh air
29.09.201419
Calculated savings potential at full load (27 car bodies/h)
prediction: volume flow rate reduction: 7.800 m3N/h
natural gas demand : 850 kW (savings: 20,6 %)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201420
waste air
waste air
clean gas
clean gas
fresh air
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
Air balance and natural gas demand of a top coat dryer at partial load state (70 %)
per hour per yearDemand natural gas: 1095 kW 7665 MWCosts natural gas: 44 €/h 308 T€/a (0,04 €/kWh)CO2‐Emission: 263 kg/h 1841 t/a (0,24 kg/kWh)
production: 7000 h/aload: 20 car bodies/hcirc. gas
circ. gas
circ. gas
circ. gas
load: 20 car bodies/h
29.09.201421
Energy savings potential with LAVA is upto 35 % at partial load state
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energy savings potential
5.LAVA
(volume flow adjustment)
6.Prospect
daily mean
operation effort/h saving/h saving/aDemand natural gas: 690 kW 405 kW 2835 MWCosts natural gas: 28 €/h 16 €/h 112.000 €/aCO2‐Emission: 166 kg/h 97 kg/h 679t/a
production: 7000 h/aload: 20 car bodies/h
recirculated
gas
circ. gas
circ. gas
circ. gas
circ. gas
waste air
waste air
clean gas
clean gas
fresh air
29.09.201422
Calculated savings potential atpartial load state (daily mean: 20 car bodies/h)
prediction: volume flow rate reduction: 6.600 m3N/h
natural gas demand : 690 kW (savings: 35,5 %)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201423
waste air
waste air
clean gas
clean gas
fresh air
Air balance and natural gas demand of a top coat dryer at idle load state (0%)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
per hour per yearDemand natural gas: 1150 kW 8050 MWCosts natural gas: 46 €/h 322 T€/a (0,04 €/kWh)CO2‐Emission: 276 kg/h 1932 t/a (0,24 kg/kWh)
production: 7000 h/a
load: 0 car bodies/hcirc. gas
circ. gas
circ. gas
circ. gas
29.09.201424
waste air
waste air
clean gas
clean gas
fresh air
Energy savings potential with LAVA is up to 59 % at idle load state
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
daily mean
operation effort/h saving/h saving/aDemand natural gas: 450 kW 700 kW 4900 MWCosts natural gas: 18 €/h 28 €/h 196.000 €/aCO2‐Emission: 108 kg/h 168 kg/h 1176 t/a
production: 7000 h/aload: 0 car bodies/hcirc. gas
circ. gas
circ. gas
circ. gas
29.09.201425
Calculated savings potential atidle load state (0 car bodies/h)
prediction: volume flow rate reduction: 4.500 m3N/h
natural gas demand : 450 kW (savings: 58,7 %)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201426
Volume flow rate reduction shown as energy flow sheet (partial load 70 %)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
LAVA can reduce the energy loss of the clean gas by 70 %
29.09.201427
Volume flow rate reduction shown as energy flow sheet (partial load 70 %)
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
LAVA can reduce the energy loss of the clean gas by 70 %
29.09.201428
Elaborate process to realize a LAVA(volume flow adjustment)
LAVA realization Project steps
1. Actual state analysis Measurements to establish the current state Evaluation of the energy demand characteristic Savings potentials and commercial viability
2. Implementationof LAVA switchgear
Implementation of LAVA controller (PLC) and visualization Connection of additional measurement instrumentation
3. Implementationof fan switchgear
Implementation of frequency inverters for exhaust air, fresh air and circulation fans (replacement of fans, if necessary)
4. Upgrade of dryer's process equipment
Temperature, pressure and volume flow instrumentation Safety technology including LEL monitoring Adjustment of safety devices
5. Connection of signal to existing controller
Definition of interface ports Connection of dryer control signals Connection of LAVA and fans switchgears
6. Start‐up of LAVA system Identification of LAVA operating parameters Adjustment of control and safety functions
7. Follow‐up inspection and documentation
System test operation and validation documentation, training and handover
LAVA is realized during ongoing production!It requires only three single production‐free days (e.g. at weekends)
weeks
0
4
8
9
12
6
7
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201429
Visualizing the LAVA switch cabinet during operation
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201430
Savings with LAVA in the volume flow adjustment mode
natural gas demand
volume flow rate
electrical energy1)
Outline
1) related to waste air‐ and fresh air fans
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect
29.09.201431
6. Summary and prospect Four options to adjust the heat balance have been discussed on current
paint drying systems energetically separation of dryer heating and waste gas purification enlargement of the waste air preheating of the TNV temperature reduction in the TNV followed by a catalyst (or in‐line‐RNV)
control of the waste air volume flow rate (dependent on the demanded heat)
the latter two options have been examined within R&D projects A lower temperature in the TNV is only useful for a static savings potential
(thermic inertia of the system) the lower temperature has to cover the full load state
reduction of waste air in TNV (and reduction of fresh air) can use the dynamical savings potential by constant temperatures and only few influences by thermal inertia has a greater savings potential as the static temperature setback
for implementation of the volume flow adjustment there is a cooperation between Crone Wärmetechnik GmbH and the CVET GmbH
4 LAVAS have been realized so far (during ongoing production)(ca. 2 years of operation experience without failures).
Outline
1.Introduction
2.Use of energy
paint drying system
3.Heat balance approaches
4.Evaluation energysavings potential
5.LAVA
(volume flow adjustment)
6.Prospect