maranda – marine application...the whole filter system (see figure 3) will be packaged in the...

DELIVERABLE 3.2 MARANDA - Grantagreement no: 735717

MARANDA – Marine applicationof a new fuel cell powertrainvalidated in demanding arcticconditionsGrant agreement no: 735717Deliverable 3.2 Salt particle filterand particle sensorcharacterisation andselection report

Authors: Sampo Saari (VTT), Johan Tallgren (VTT), Jari Ihonen (VTT)

Confidentiality:Submission date:Revision:

Public31.8.2018-

MARANDA - Grant agreement no:735717 Deliverable 3.2

1 (19)

Report’s title

Deliverable 3.2 Salt particle filter and particle sensor characterisation and selection reportCustomer, contact person, address Order reference

Lionel Boillot, FCH JU Grant agreement no:735717

Project name Project number/Short name

Marine application of a new fuel cell powertrain validated indemanding arctic conditions

MARANDA

Author(s) Pages

VTT: Sampo Saari, Johan Tallgren, Jari Ihonen 19

Summary

Both fuel cell container and hydrogen storage container in MARANDA project requirecontrolled inlet air filtration for ventilation air and for fuel cell cathode air.

For this purpose commercial salt particle filters from Camfil AB were characterised by VTT.The filters included weather guard (Camfil CamVane-100), preliminary purification filter(Camfil GT Aeropleat G4) and gas turbine filter (Camfil CamGT H12).

Weather guard and preliminary purification filter were not able to filter fine (<10 mm) KClparticles. However, their filtration efficiency for larger particles was good, showing that theycan work as pre-filters and increase the life-time of the gas turbine filter (Camfil CamGT H12).

The gas turbine filter could filter over 99.8% of the KCl particles, which were larger than 0.5mm, at nominal flow (1000 m3/hour) conditions. In addition, the efficiency for small (0.2 mm)DEHS (Di-Ethyl-Hexyl-Sebacat) particles was over 99.8%. The filtration efficiency did notdecrease in loading test.

The total pressure drop of the filter package consisting all the filters was only about 200 Pa (2mbar). This pressure drop can be used for the selection of ATEX rated fan for the ventilation.

For conditioning monitoring of filters, and for controlling air quality inside the container,different particle monitoring options (Shinyei PPD71, Vaisala AQT420, Pegasor AQ, Fidas®Frog) were evaluated. From these options, Shinyei PPD71 and Vaisala AQT420 seem to bethe most suitable options for the selected application in arctic environment.

The selected filter package will be installed for both fuel cell container and hydrogen storagecontainer. Selected particle monitoring solution will be integrated in high level control systemof the fuel cell container. The complete filtering solution and particle monitoring solution willbe validated in Aranda vessel in real life operation.

Confidentiality Public

MARANDA - Grant agreement no:735717 Deliverable 3.2

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Deliverable 3.2 2MARANDA, H2020 FCH JU project no. 735717

ContentsGlossary................................................................................................................................. 2

1. Introduction ....................................................................................................................... 3

2. Materials and methods ..................................................................................................... 4

2.1 Filtration characterization ......................................................................................... 42.1.1 Test system .................................................................................................. 42.1.2 Filters ........................................................................................................... 52.1.3 Test matrix.................................................................................................... 6

2.2 Particle sensor characterization ................................................................................ 9

3. Results ........................................................................................................................... 10

3.1 Filtration characterization ....................................................................................... 103.1.1 Time series ................................................................................................. 103.1.2 Filtration efficiency curves .......................................................................... 133.1.3 Pressure drop of filters................................................................................ 143.1.4 Conclusions ................................................................................................ 16

3.2 Particle sensor characterization .............................................................................. 17

4. Selection decision and justification ................................................................................. 19

Glossary

ATEX ATmosphere EXplosiblesDEHS Di-Ethyl-Hexyl-SebacatPM1 Particle Mass concentration up to 1 µmPM2.5 Particle Mass concentration up to 2.5 µmPM10 Particle Mass concentration up to 10 µm


1. Introduction

In MARANDA project a filter and filter monitoring solution is developed for both FC systemcontainer and for hydrogen storage container. Originally, air filtering was considered only forfuel cell system or for a container for the fuel cell system.

In MARANDA project two options were considered for the hydrogen storage. A completelyopen storage system on the deck of the vessel, or a closed container with controlledventilation. This container would also be placed on the deck.

In case the open storage system would be used, any leaking hydrogen would be diluted inair safely. This would be very beneficial in terms of safety assessment. However, in thisoption two major problems were identified. Firstly, all the components of the storage systemwould be exposed to salty marine environment. Secondly, in arctic conditions ice accretionon ship superstructures is a serious safety issue. In the open hydrogen storage system allthe components of the storage system would be exposed to the danger of ice accretion.However, also in the closed container the ice accretion must also be considered in designand operation of the storage. The most critical parts are the inlet and exhaust of theventilation air.

Air filtering can be considered as the most problematic component for fuel cell systems inmarine applications. This is due to numerous reasons. The salt content of the air may bevarying by two orders of magnitude making the estimation for the particle filter changinginterval impossible. The salt is not detrimental only for fuel cell stack, but also for all otherexterior components. When filter solution is designed it is clear that condition monitoringsystem (pressure sensors, particle counters, chemical sensors) would be beneficial.

There are number of air filters available for the FC systems. However, these filters aretypically having relatively low particulate efficiency. For example, Freudenberg FiltrationTechnologies promises only 98% particulate efficiency. This may not be enough in marineconditions with high amount of salt particles in the air.

In the selected fuel cell system container solution all the ventilation air of the fuel cellcontainer is filtered with particle filters. A part of the filtered air is then further purified bychemical filter before it is used by FC system. In this solution the condition monitoringsystem would also be easier to design.

The use of conditioning monitoring enables simplified air filter system for the fuel cell system,with lower pressure drop and improved system efficiency. When the intake of the FC air istaken from the container, the air quality (particles, NO2, SO2) inside the container can beused as input for deciding filter changing interval for the fuel cell system cathode air inletfilter. In addition, the pressure drop of the filter can be used for this. Pressure drop and airquality monitoring form together the filter conditioning monitoring solution.


2. Materials and methods

2.1 Filtration characterization

2.1.1 Test system

First, the filter components were characterized separately in order to analyze filtrationefficiency and pressure drop of individual filters. After that, the whole filter assembly wascharacterized in realistic operation conditions.

The studied parameters were pressure drop over the filter with varying airflow and particlecollection efficiency of the filter. The pressure drop gives information on the loading andlifetime of the filter and the particle collection efficiency shows the filtration performance.

The collection efficiency was measured with DEHS (Di-Ethyl-Hexyl-Sebacat) particles in dryconditions similar to the EN779 test standard. The test gives information on the initialperformance of the filter. DEHS particles are hydrophobic and do not have remarkableloading effect on the filter. After that, the collection efficiency were measured with salt-waterdroplets in humid conditions in order to simulate filter performance in marine conditions. Theparameters to be varied were airflow, relative humidity and addition of particles:

1) Airflow: 380, 690 and 1000 m3/h2) Relative humidity: 40, 70 and 100%

Figure 1: The filter test system in high humid conditions.

The filter test system is shown in Figure 1. Humidity of the supply air was adjusted using ahumidifier and a cooling coil. Salt-water droplets and DEHS particles were sprayed to amixing chamber to get homogenous mix before the filter.

Pressure drop was measured continuously over the filter using Micatrone Micaflex MF-PDmanometer with 1 Pa resolution.


Droplet/particle concentration from the upstream and downstream of the filter was sampledalternately using automated valves. Drying air was added to the sample in order to get salt-water droplets dried before particle instrument. Particle size distribution and concentration ofthe upstream and downstream samples were measured using the Fidas Frog particleinstrument (https://www.palas.de/en/product/fidasfrog) in the size range of 0.2 - 10 µm.Schematic PI diagram of the test system and components is shown in Figure 2.

Figure 2: Schematic PI diagram of the components and data logging of the test system.

2.1.2 Filters

Commercial and in-house particle filter options were evaluated based on manufacturer data,before selecting most promising solution for the characterization. The main commercialoptions were Camfil filters (https://www.camfil.com) and Premaberg filter solutions. Camfilfilters were selected as they provided a possibility to combine different filter modules(weather guard, preliminary purification filter, fine filter) while in Premaberg filters differentmodules are integrated. Camfil gas turbine filters filter performance with salt particles (KCl)needed to be verified.

VTT has also developed an own particle filter solution (TurboSwing), which has beencommercialized for grease separation (http://www.jeven.be/turboswing-en.php). This solutionwas not considered feasible, mostly due to volume constrains in fuel cell and hydrogenstorage containers.

The air filter solution employed in the fuel cell system should be suitable for marineconditions and possible solutions will be characterized prior to installment in the ship.


The chosen filter solutions is composed of the following parts:1) Camfil CamVane-100 weather guard2) Camfil GT Aeropleat G4 preliminary purification filter3) Camfil CamGT H12 gas turbine filter

The whole filter system (see Figure 3) will be packaged in the Camfil Camcube HF filterhousing1.

Figure 3: The selected filters: (1) Camfil CamVane-100 weather guard, (2) Camfil GTAeropleat G4 preliminary purification filter, (3) Camfil CamGT H12 gas turbine filter.

2.1.3 Test matrix

Firstly, all components (weather guard, G4 and H12) were measured individually andsecondly, the whole filter package was studied as whole. The minimum air flow in the FCsystem is 380 m3/h and the maximum is 1000 m3/h. Therefore, in each test, the pressuredifference over the studied component was measured with different airflows (380 - 1000m3/h) and with various relative humidities (40 - 100%). After that, filtration efficiency weretested using first DEHS particles, then salt-water droplets and then again DEHS particles.

Table 1 presents the test matrix covering characterization of the different components. Filter1 denotes the CamVane-100 weather guard, filter 2 the GT Aeropleat G4 preliminarypurification filter and filter 3 denotes the CamGT H12 gas turbine filter. In addition to thepressure difference over the filter with different relative humidity (RH), the effect of bothDEHS particles and salt-water droplets are studied.

1 https://www.camfil.fi/Tuoteryhmat/Saasuojat-suodatinkotelot-ja-asennusjarjestelmat/Suodatinkotelot/CamCube-HF-fi/


Table 1: Test matrix for the individual component measurements. Filter 1 denotes theCamVane-100 weather guard, filter 2 the GT Aeropleat G4 preliminary purification filter andfilter 3 denotes the CamGT H12 gas turbine filter.

Setup Filter RH(%)

Air flow(m3/h)

DEHSparticles

Saltdroplets

Preparation1.1 1 40 3801.2 1 40 10001.3 1 70 3801.4 1 70 6901.5 1 70 10001.6 1 100 3801.7 1 100 10002.1 1 40 380 x2.2 1 40 1000 x2.3 1 100 380 x2.4 1 100 1000 x2.1 repeat 1 40 1000 x

Change of filters3.1 2 40 3803.2 2 40 10003.3 2 70 3803.4 2 70 6903.5 2 70 10003.6 2 100 3803.7 2 100 10004.1 2 40 380 x4.2 2 40 1000 x4.3 2 100 380 x4.4 2 100 1000 x4.1 repeat 2 40 1000 x

Change of filters5.1 3 40 3805.2 3 40 10005.3 3 70 3805.4 3 70 6905.6 3 70 10005.7 3 100 3805.8 3 100 10006.1 3 40 380 x6.2 3 40 1000 x6.3 3 100 380 x6.4 3 100 1000 x6.1 repeat 3 40 1000 x


After individual filters were characterized the next step was to characterize the filter solutionas a whole (water guard, G4 and H12).

Table 2 presents the test matrix for the whole filter package. Focus of the test was loadingeffects on the filtration and the pressure drop. Firstly, the effect of humidity and airflow wasstudied for the clean filter package. Secondly, the loading effect of dry and humid saltparticles were studied. Dry and humid salt particles were alternated until the pressuredifference of the filter assembly would exceed 600 Pa with humid salt. The idea was to studyfiltration efficiency and pressure drop at the highest load (flow rate 1000 m3/h), wherepossible problems would be displayed.

Table 2: Test matrix for characterization of the whole filter package, taking the effect ofdiffering RH as well as capacity loading into account.

Setup Filter RH Air flow DEHSparticles

Saltdroplets

Preparation7.1 1+2+3 40 3807.2 1+2+3 40 10007.3 1+2+3 70 3807.4 1+2+3 70 6907.5 1+2+3 70 10007.6 1+2+3 100 3807.7 1+2+3 100 1000

8.1 1+2+3 40 1000 x8.2 1+2+3 100 1000 x8.1, repeat 1+2+3 40 1000 x


2.2 Particle sensor characterization

Characterization of potential particle monitoring solutions for the FC system is importantbefore component selection in the field performance tests. Performance of several particlesensors were studied in the laboratory test system. The low-cost sensors (e.g. ShinyeiPPD71) can be used in monitoring filtration performance to prevent e.g. leakages and otherhazardous situations.

The sensors were installed parallel with an expensive reference instrument (Fidas Frog,Palas GmbH, ca. 13 000 €). Particle concentration response and lower limit of detection willbe studied. Also loading of the sensors in harsh environment are analyzed. Three potentialsensors are going to be tested:

• Shinyei PPD71, optical sensor (PM2.5), ca. 100 €,https://www.shinyei.co.jp/stc/eng/optical/main_ppd71.html

• Vaisala AQT420, optical sensor (PM2.5 and PM10) and gas sensor (NO2, SO2, CO,O3), ca. 5000 €, https://www.vaisala.com/fi/products/instruments-sensors-and-other-measurement-devices/weather-stations-and-sensors/aqt420

• Pegasor AQI, electrical sensor (particle surface area, particle number, PM2.5, CO2,relative humidity), ca. 9000 €, http://pegasor.fi/en/our-technology/air-quality-monitoring/indoor-air-quality-monitoring/

The Shinyei PPD71 represents a simple low-cost optical sensor. The Vaisala AQT420 isoptical sensor designed for outdoor use and has proven lifetime tests. The Pegasor AQI iselectrical charging based sensor that is designed for ultrafine particle measurement.

Figure 4: The selected particle sensors and the reference instrument (Palas Fidas Frog).

The operational temperature limits for the sensors are as follows:

· Shinyei PPD71: -10 °C …+60 °C· Vaisala AQT420: -30 ... +40 °C and limited performance: -40 ... +50 °C· Pegasor AQI 0 - 50 °C· Fidas® Frog 0 – 40 °C

This means that only Vaisala AQT420 is fully suitable for the intended use, if the fuel cellssystem container is not heated. As Shinyei PPD71 can operate -10 °C it is also a goodcandidate.


3. Results

3.1 Filtration characterization

3.1.1 Time series

Particle mass concentrations (PM1, PM2.5, PM10 and PM total) before and after filter duringthe test run are shown in Figure 5 (water guard, filter 1), Figure 6 (G4, filter 2) and Figure 7(H12, filter 3).

The periodic (changing time is few minutes) lower values represent the concentration afterthe filter and the higher values represent the concentration before the filter. Oneexperimental condition was studied between 15 and 60 minutes, as shown in Figures 5-7.

The collection efficiency for PM values can be seen from figures, e.g., for the filter 3 (H12)the PM2.5 concentration decreased to 1/1000 in which case the collection efficiency is99.9%.

Figure 5: Particle mass concentrations (PM1, PM2.5, PM10 and PM total) before and afterthe filter 1 (water guard) during the test run.


Figure 6: Particle mass concentrations (PM1, PM2.5, PM10 and PM total) before and afterthe filter 2 (G4) during the test run.

Figure 7: Particle mass concentrations (PM1, PM2.5, PM10 and PM total) before and afterthe filter 3 (H12) during the test run.

Particle mass concentrations (PM1, PM2.5, PM10 and PM total) during the loading test inhigh humid conditions for the whole filter package are shown in Figure 8.

Dry air addition caused sample dilution (30%) that is not corrected in the figures. PM10concentration during the loading was about 30 000 µg/m3 at the instrument, i.e. the realPM10 concentration was around 100 000 µg/m3. This is over 10 000 times higher thannormal concentration in marine environment that is typically around 10 µg/m3.

Therefore, the used 12 hours KCl loading in high humid conditions represented normalmarine salt loading during 13 years. The results showed steady behaviour in filtrationefficiency indicating no leakages during the loading test.


Figure 8: Particle mass concentrations (PM1, PM2.5, PM10 and PM total) during salt-waterloading test of the whole filter package (8.2 in Table 2). Sample dilution is not corrected.

12:0

015

:00

time

100

102

104

PM1

PM2.

5PM

10PM

tota

l


3.1.2 Filtration efficiency curves

The filtration efficiency curves for DEHS particles and salt-water droplets in high humidconditions are shown in Figure 9 (weather guard, filter 1), Figure 10 (G4, filter 2), Figure 11(H12, filter 3) and Figure 12 (the whole filter package 1+2+3).

The weather guard and G4 showed strongly particle size dependent efficiency curve, having50% efficiency typically particles larger than 10 µm. The weather guard removed very wellthe large droplets (> 10 µm) and thus protecting the next filters. The G4 filter removedparticles and droplets larger than 5 µm and thus prevent salt loading and increase thelifetime of the H12 filter.

The H12 filter and the whole filter package showed similar smooth filtration efficiency at wideparticle size range having the average filtration efficiency better than 99.8%. This is verygood result and well above the usual quality criteria for the FC system.

Figure 9: Particle filtration efficiency curves for DEHS particles (left) and KCl-water droplets(right) for the filter 1.




Figure 12: Particle filtration efficiency curves at the start and end of the KCl-water dropletsloading test for the whole filter package (1+2+3).

3.1.3 Pressure drop of filters

Pressure drop results of the filters during various situations according to the test matrix areshown in Table 3. Overall, the pressure drop values were acceptable and did not increasemuch in the high humid conditions. The maximum pressure drop elevation in the humidconditions were only 4% with the filter 3.


Table 3: Pressure drop (∆p) results for the individual component measurements.

Setup Filter RH(%)

Air flow(m3/h)

DEHSparticles

Saltdroplets

∆p (Pa)

Preparation1.1 1 40 380 111.2 1 40 1000 661.3 1 70 380 111.4 1 70 690 341.5 1 70 1000 681.6 1 100 380 121.7 1 100 1000 662.1 1 40 380 x 122.2 1 40 1000 x 682.3 1 100 380 x 122.4 1 100 1000 x 702.1 repeat 1 40 1000 x 69

Change of filters3.1 2 40 380 43.2 2 40 1000 73.3 2 70 380 43.4 2 70 690 53.5 2 70 1000 73.6 2 100 380 43.7 2 100 1000 74.1 2 40 380 x 44.2 2 40 1000 x 74.3 2 100 380 x 54.4 2 100 1000 x 94.1 repeat 2 40 1000 x 9

Change of filters5.1 3 40 380 255.2 3 40 1000 705.3 3 70 380 255.4 3 70 690 475.6 3 70 1000 705.7 3 100 380 255.8 3 100 1000 726.1 3 40 380 x 256.2 3 40 1000 x 706.3 3 100 380 x 296.4 3 100 1000 x 746.1 repeat 3 40 1000 x 72


The pressure drop results during the whole filter package (1+2+3) tests are shown in Table4. The total pressure drop over the filter package was almost the same as the combinedpressure drops of the individual filters. Pressure drop increased up to 200 Pa during 12hours loading in high humid conditions and returned to the initial values after drying. Overall,the 1+2+3 filter package combination performed very well during the tests.

Table 4: Pressure drop results of the whole filter package tests.

Setup Filter RH Air flow DEHSparticles

Saltdroplets

∆p (Pa)

Preparation7.1 1+2+3 40 380 377.2 1+2+3 40 1000 1457.3 1+2+3 70 380 377.4 1+2+3 70 690 847.5 1+2+3 70 1000 1417.6 1+2+3 100 380 377.7 1+2+3 100 1000 145

8.1 1+2+3 40 1000 x 1478.2 1+2+3 100 1000 x 2048.1, repeat 1+2+3 40 1000 x 1498.2, repeat 1+2+3 100 1000 x 196

3.1.4 Conclusions

The results showed very good performance for the selected filters.

Concerning both filtration efficiency and pressure drop the 1+2+3 filter package combinationperformed very well during the tests. DEHS particle results before and after the salt-waterexposure test showed similar results showing that no leakages or performance degradationwere observed. The preliminary filters (weather guard and G4) prevent the larger dropletsand particles to penetrate to the high efficiency filter H12 and thus enable longer life time inharsh environment. Pressure drop increased up to 200 Pa during 12 hours loading in highhumid conditions and also returned to the initial values after drying.

The measured maximum pressure drop (200 Pa) at 1000 m3/h can be used as design valuefor the ATEX rated ventilation fans. Depending on the efficiency of the fan, the powerconsumption is expected to be between 200 and 400 W.


3.2 Particle sensor characterization

Comparison of particle mass concentrations (PM1, PM2.5, PM10) of particle sensors(Shinyei, Pegasor and Vaisala) and reference instrument (Palas Fidas Frog) is shown inFigure 13.

The Shinyei sensor has fast response time and follows the reference PM2.5 very well. Signalof the Pegasor sensor follows also quickly the reference PM2.5, but has also high oscillationthat is mainly due to electric noise that occurs near to the detection limit of the sensor. TheVaisala sensor also follows the reference PM2.5, but has much slower response time (>10min) since it is designed for outdoor air quality monitoring application. The slow responsetime may be a problem in monitoring, but on the other hand, it helps to achieve longerlifetime for the sensor.

Figure 13: Particle mass (PM1, PM2.5, PM10) concentration comparison of the sensors(Shinyei, Pegasor and Vaisala) and the reference instrument (Palas Fidas Frog).

Figure 14 shows the Shinyei sensor response at wide particle concentration range. Theresults showed that PPD71 follow the reference PM2.5 concentration very well atconcentration range of 4 - 500 µg/m3 having detection limit around 1 µg/m3. The low-costPPD71 sensor has high potential in monitoring filtration performance of fuel-cell system. Thelong-term testing is still needed to get information on reliable lifetime of the sensor.

time10-1

100

101

102

mas

sco

ncen

tratio

nµg

/m3

PM1PM2.5PM10Shinyei PM2.5Pegasor PM2.5Vaisala PM2.5


Figure 14: PM2.5 concentration comparison between the Shinyei PPD71 particle sensor andthe reference instrument (Palas Fidas Frog).

massconcentrationµg/m3


4. Selection decision and justification

The air filtration in the fuel cell system is critical due to the contamination and damage risks.Especially high humidity, water droplets, salt particles and ship emissions cause extrachallenges in marine environment. Therefore, the selection criteria for air filtration solutionare strict. The main criteria for the filtration performance are filtration efficiency of dropletsand fine particles, pressure drop over the filter and survival in humid conditions. The testedfilter solutions consisted of the three functional elements:

1) Camfil CamVane-100 weather guard2) Camfil GT Aeropleat G4 preliminary purification filter3) Camfil CamGT H12 gas turbine filter

Aim of the filter 1 was to prevent large water droplets (>10µm) penetrating into the filtersystem. Filter 1 is open type coalescer filter and has long lifetime.

The results showed that filter 1 can remove large water droplets well enough. Function of thefilter 2 is to remove large particles entering into the main filter 3, so the lifetime of the filter 3is longer and pressure drop does not increase so much due the dust loading. The filter 2 haslow pressure drop and can stand high dust loading. The main filter 3 is a high efficiencyparticle filter (HEPA), which can remove 99.9% of particles in wide particle size range toensure pure air entering into the fuel cell system. The test results showed that the wholefiltration solution (1+2+3) has both high filtration efficiency (over 99.8%), low pressure drop(< 200Pa), long lifetime and good resistance in humid conditions. The selected filtrationsolution fits well to the fuel cell system in marine conditions.

Failure of the filtration due to the leakage or damage in the filtration system or in theoperation room should be taken into account in the fuel cell system. Low-cost particlesensors can be used to monitor occurrence of failure situations and to prevent greaterdamage to the fuel cell system. The main criteria for the particle sensor selection aresensitivity, detection limit, time resolution, reliability and lifetime. The selected particlesensor, Shinyei PPD71, was tested and compared with the reference instrument inlaboratory conditions.

The results for Shinyei PPD71 showed that sensitivity, detection limit and time resolutionwere sufficient for the monitoring function of the fuel cell system. However, reliability andactual lifetime could not be shown in these laboratory tests. Shinyei PPD71 was selected forthe particle monitoring solution to the real field operation tests. In addition, Vaisala AQT420can be tested in parallel with Shinyei PPD71. This, however, will be decided closer to thefield test start as new sensors may become available.

maranda – marine application...the whole filter system (see figure 3) will be packaged in the...

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