energetic evaluation and assessment by ......energy consumption of a filter test using a filter test...

ENERGETIC EVALUATIONAND ASSESSMENT BY FILTRATION SPECIFIC PARAMETERS

OF CLEANABLE FILTER MEDIA USING STANDARDIZED FILTER TEST RIGS

Dipl.-Ing. Dr. Thomas Laminger

Vienna University of Technology

Institute of Chemical Engineering

Mechanical Process Engineering and Clean Air Technology

Institute of Chemical EngineeringInstitut für Verfahrenstechnik, Umwelttechnik und Technische Biowissenschaften

Vienna University of TechnologyTechnische Universität Wien

Content

2

• Introduction

Criteria for choosing filter media

Standards for evaluation of filtration and energy related parameters of filter media

• Definition of an energy consumption value of a filter test usinga standardized filter test rig (ISO 11057)

• Detailed experimental results of an exemplary filter test including the energy consumption value

• Comparison of different filter media with regard to the energy consumption value and the mean clean gas concentration

• Summary

• Analogies to other filter systems



Introduction

Standards for evaluation of filter media parameters of dust separation systems:

• Filtration specific parameters:

Depth filters: e.g. DIN EN 779

HEPA filter: e.g. DIN EN 1822

Cleanable dust filters: e.g. VDI 3926, EN ISO 11057…

• Energy related parameters:

EUROVENT 4/11 for depth filters (tested according to DIN EN 779)

Criteria for choosing a filter system:• Maximum permissible value: clean gas concentration value…• Operation conditions: dust properties, temperature…• Costs:

Fixed costs (investment costs) Operation costs (constantly or repeatedly incurred cost)



Introduction

𝑊 =𝑞. ∆𝑝. ℎ

ƞ. 1000

W….Annual Energy consumption [kWh]q….....Volume flow rate (0.944 m³/s)∆𝑝…..Averaged Pressure drop in EN 779 test [Pa]h….....Operation time (6000 h)Ƞ…….Fan efficiency (0.9)

EUROVENT 4/11 for depth filters (tested according to DIN EN 779)

“ENERGY EFFICIENCY CLASSIFICATION OF AIR FILTERS

FOR GENERAL VENTILATION PURPOSES”

This guideline define a method of air filter classification with regard to energy-efficient operation



Objective

5

To evaluate and compare different cleanable dust filter media beside filtration specific parameters (e.g. residual pressure drop…) an evaluation with regard to the energy demand is also desirable.

Objective:

To develop a value for the total energy consumption for a ISO 11057 test rig to compare different filter media in terms of energy consumption together with their penetrated amount of particles.



Energy consumption of a filter test using a filter test rig (ISO 11057)

6

Power consumption of n filtration cycles Ptot,n [W]

• Power consumption of the fan Pfan,n

• Power consumption for the needed

compressed air of the pulse-jet cleaning Pcleaning,n

Test filterAbsolut filter

Pressurized air tank

Ambient air

Dust disperser

Pressured

air

Fan

Scattered light

particle sensor

Ptot,n = Pfan,n + Pcleaning,n

Pfan,n = ∆ pfilter,n. V

P cleaning,n =∆ptank. Vtank. n

i=1n tcycle,i

∆ pfilter,n…. Mean pressure drop of n

filtration cycles [Pa] V……………. Air flow rate [m³/s]∆ptank …….Air tank pressure (before and

after cleaning) [Pa]Vtank……….Volume of the air tank [m³]tcycle,i…….. Cycle duration of the filtration

cycle i [s]n……………..Number of filtration cycle [-]



Energy consumption of a filter test using a filter test rig (ISO 11057)

7

Volume-related total energy consumption of

n filtration cycles EV,tot,n [Wh/m³] 𝐸𝑉,𝑡𝑜𝑡,𝑛 =𝐸𝑡𝑜𝑡,𝑛

𝑉𝑡𝑜𝑡,𝑛=

𝑃𝑡𝑜𝑡,𝑛 .𝑡𝑡𝑜𝑡,𝑛

𝑉𝑡𝑜𝑡,𝑛=

𝑃𝑡𝑜𝑡,𝑛 𝑉

𝐸𝑉,𝑡𝑜𝑡,𝑛 = ∆ 𝑝𝑓𝑖𝑙𝑡𝑒𝑟,𝑛 +∆𝑝𝑡𝑎𝑛𝑘.𝑉𝑡𝑎𝑛𝑘.𝑛

𝑉. 𝑖=1𝑛 𝑡𝑐𝑦𝑐𝑙𝑒,𝑖

l

Etot,n………. Volume-related total energy consumption of n filtration cycles [Wh/m³]

Vtot,n…….… Total air volume throughput from the beginning of a filter test to the end of the filtration cycle n [m³]

ttot,n……… Total duration from the beginning of a filter test to the end of the filtration cycle n [s]

∆ pfilter,n…. Mean pressure drop of n

filtration cycles [Pa] V……………. Air flow rate [m³/s]∆ptank ……Air tank pressure (before and

after cleaning) [Pa]Vtank…… . .Volume of the air tanktcycle,i…….. Cycle duration of the filtration

cycle i [s]n……………..Number of filtration cycle [-]

Ws

m3 =J

m3 =Nm

m3 =N

m2 = Pa l



Ambient air

Dust disperser

Pressured

air

Fan

Scattered light

particle sensor



Mean clean gas concentration

Mean clean gas concentration of

n filtration cycles cclean,n [mg/m³]

Using a scattered light particle sensor with continuous single

particle detection in order to determine the mean clean gas

concentration

𝑐𝑐𝑙𝑒𝑎𝑛,𝑛 =1

𝑖=1𝑛 𝑡𝑐𝑦𝑐𝑙𝑒,𝑖

. 𝑖=1

𝑛

𝑐𝑐𝑙𝑒𝑎𝑛,𝑖 . 𝑡𝑐𝑦𝑐𝑙𝑒,𝑖

cclean,i…… Mean clean gas concentration of

the filtration cycle i [P/cm³] or [mg/m³]

tcycle,i….. Cycle duration of the filtration

cylce i [s]n…………….Number of filtration cylces [-]



Ambient air

Dust disperser

Pressured

air

Fan

Scattered light

particle sensor



Comparison of different filter media

Filter face velocity m³/(m²h) 120

Dust concentration g/m³ 5

Test dustSasol Pural NF

d10,3=1.2µm, d50,3=4.5µm, d90,3=21.0µm

Pressure drop prior to pulse-jet cleaning

Pa 1000

Tank pressure MPa 0,5

Valve opening time ms 60

Number of fitration cycles [-] 30

Effective filter area m² 0.0177

Test conditions


using two single parameters:

• Ev,tot,n [Wh/m³]

• cclean,n [mg/m³]

for n=30 of the first 30 filtration cycles of a new filter medium

for n=30 of the 30 filtration cycles after artificial aging

1. PhaseOperating with filter in new condition

30 pressure controlled cycles

2. Phase Artificial aging2500 time controlled

cycles (20s)

3. Phase Stabilization10 pressure controlled

cycles

4. PhaseOperating with filter in aged condition

30 pressure controlled cycles

Test phases (according to the ISO 11057)



Exemplary filter medium: Needle felt (PI); 1st test phase (new filter medium)

Development of the pressure drop and

clean gas concentration over the time

Filtration cycle duration and residual pressure

drop over the number of filtration cycles



0

4

8

12

16

0,00

0,10

0,20

0,30

0,40

0 10 20 30

Me

an cle

an gas co

nce

ntratio

n

cclean

,n[m

g/m³]

Vo

lum

e-r

ela

ted

to

tal e

ne

rgy

con

sum

pti

on

E V

,to

t,n

[Wh

/m³]

Number of filtration cycles [-]

Needle felt (PI)

Volume-related total energyconsumption

Mean clean gas concentration

Exemplary filter medium: Needle felt (PI); 1st test phase (new filter medium)

Volume-related total energy consumption Ev,tot,n and

mean clean gas concentration cclean,mean,n over the number of filtration cycles

𝐸𝑉,𝑡𝑜𝑡,𝑛 = ∆ 𝑝𝑓𝑖𝑙𝑡𝑒𝑟,𝑛 +∆𝑝𝑡𝑎𝑛𝑘.𝑉𝑡𝑎𝑛𝑘.𝑛

𝑉. 𝑖=1𝑛 𝑡𝑧𝑦𝑘𝑙𝑢𝑠,𝑖

l 𝑐𝑐𝑙𝑒𝑎𝑛,𝑛 =1

𝑖=1𝑛 𝑡𝑐𝑦𝑐𝑙𝑒,𝑖

. 𝑖=1

𝑛

𝑐𝑐𝑙𝑒𝑎𝑛,𝑖 . 𝑡𝑐𝑦𝑐𝑙𝑒,𝑖



Exemplary filter medium: Needle felt (PI)

Development of the pressure drop and

clean gas concentration over the time

2

34

1




Filtration cycle duration and residual pressure

drop over the number of filtration cycles

Operating with filter in new

condition

Operating with filter in aged

condition





mean clean gas concentration cclean,mean,n over the number of filtration cycles

Operating with filter in new

condition

Operating with filter in aged

condition




𝐸𝑉,𝑡𝑜𝑡,30 ↗

cclean,30 ↘


mean clean gas concentration cclean,n of 30 filtration cycles

(1st test phase – operating with filter in new condition)

Exemplary criterion:

Mean clean gas

concentration <1 mg/m³

FM 4 with lowest EV,tot,30



Analogies to other filter systems

• Filter systems can vary concerning their different mechanism of regeneration, operation principle. By variation of one single parameter (e.g. filter medium, regeneration time, regeneration intensity…) the filtration behaviour and the energy consumption is influenced and both gives an unique pair of indicator.

• An energy consumption value should therefore include the main indicators for operation (e.g. pressure drop, energy for regeneration, blower or pump energy demand… ) which are specific for a filter system.

• Notice: The usage of the energy consumption value and/or filtration parameters which are resulted from laboratory tests, has to be done very carefully as many further parameters have to be considered.



Summary

• A volume–related energy consumption value (Ev,tot,n) was developed to have one single parameter to compare different cleanable dust filter media regarding to their energy consumption. This volume-related energy consumption value adds the needed average energy for the fan and the average energy for the jet-pulse cleaning at a filter test rig.

• Further the mean clean gas concentration (cclean,n) was used to determine the particle penetration throughput the filter media in order to characterize the filtration efficiency of a filter medium.

• Different filter media were tested at a modified filter test rig (according to ISO 11057) with a scattered light sensor for the measurement of the clean gas concentration, in order to determine the values Ev,tot,n and cclean,n.

It was shown that using both values can be used for an easy selection of an adequate filter medium, which has been tested at the test rig.

Generally, a lower clean gas concentration cclean,n can only be reached with a higher volume–related energy consumption value (Ev,tot,n).

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energetic evaluation and assessment by ......energy consumption of a filter test using a filter test...

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