ON BOARD MEASUREMENTS OF SCRUBBER PERFORMANCE ON VESSELS Tadeusz Borkowski Maritime University of Szczecin
Contents: 1. Background wet scrubber types Wet Scrubbing classic functional principle of operation Wet and Dry Scrubbing current approach 2. Gas Cleaning System list of manufacturers 3. EGCS installations number in service 4. Regulatory requirements 5. On board survey methodology 6. Ship s routine voyage and relevant EGCS operation 7. emission in open loop mode 8. Sea and washwater parameters in open loop mode 9. emission and sea water parameters in closed loop mode 1. Conclusions
Wet Scrubbing classic functional principle of operation Wet scrubbers Packed Bed Packed Bed Tower Bath Packed bed
Membrane Wet and Dry Scrubbing current approach Wet scrubbers Dry scrubber Venturi SO 2 Venturi Cyclonic Membrane
Gas Cleaning System list of manufacturers WARTSILA AEC MARITIME WÄRTSILÄ MOSS ANDRITZ AIR POLLUT. CONTROL CHINA ENVIRONMENTAL PROJECT ECOSPRAY TECHNOLOGIES LANGH TECH PURETEQ ALFA-LAVAL CLEAN MARINE FUJI ELECTRIC MAN DIESEL SAACKE MARINE SYSTEMS BABCOCK NOELL CR OCEAN ENGINEERING LAB MARINE EXHAUST SOLUTIONS TRITON EMISSION SOLUTIONS INC. BLUESOUL DUPONT BELCO CLEAN AIR IONADA MUNTERS YARA MARINE
EGCS installations number in service Ships equipped with EGCS TANKER 39 SERVICE 2 RORO SHIP GENERAL CARGO 25 CRUISE SHIP CONTAINER 27 113 11 Scrubber units in service 6 5 4 3 2 1 BULK CARRIER 24 5 1 15 Source: IHS Maritime 217 Source: IHS Maritime 217 Estimated number of scrubber units onboard In Service 843 Keel laid 13 Launched 16 On order and not commenced 21 Under construction 2 Total 895 Source: IHS Maritime 217
Regulatory requirements IMO Resolutions: MEPC.13(53), MEPC.17(57) and MEPC.184(59) 29; Guidelines for Gas Cleaning Systems, adopted on 17 July 29 emissions compliance limits For EGC systems operating on conventional fuel oils, exhaust emission compliance with the equivalent fuel oil sulphur content is verified from the measured SO2/CO2 concentration ratio Fuel Oil Sulfur Content (% m/m ) discharge and limits Emission Ratio SO 2 (ppm)/co 2 (% v/v ).1 4.3 1. ph criteria The ph of the discharged wash water from the scrubbing process should be no lower than 6.5 units 2. PAH* concentration The washwater maximum continuous PAH concentration is not to be greater than 5 μg/ltr above water PAH concentration 3. Turbidity The turbidity of the EGC unit washwater should not exceed 25 NTU above *Polycyclic the Aromatic water Hydrocarbons turbidity
On board survey methodology EGCS Operational survey EGCS documenation EGCS compliance EGCS operational data Ship Propulsion SO x Emissions Compliance Plan - SECP EGCS Technical Manual - ETM Onboard Monitoring Manual - OMM EGCS efficiency EGCS running cost emissions discharge Operating parameters Ship s speed Main engine power Auxiliary electric load Electronic Logging System - EGC EGCS reliability Electrical consumption Fuel oil consumption Emission factors NaOH consumption Sludge discharge
6.5 MW PEM 6.5 MW PEM 4.5 MW 4.5 MW 4.5 MW 4.5 MW Ship s propulsion and EGCS layout Ship s Diesel-Electric main/auxiliary propulsion Multiunit Hybrid Gas Cleaning System SO 2 SO 2 SO 2 SO 2 CO 2 CO 2 CO 2 CO 2 G ~ G ~ G ~ G ~ 6.6 kv 6.6 kv 44 V 44 V Main Engine specification Type MaK 6M 552 C Engine 4 stroke, direct injection Rated power 45 kw Rated speed 5 rpm Bore 45 mm Stroke 52 mm gas temperature - max 65 C
Ship s routine voyage and relevant EGCS operation 2 2 14 Ship speed [kts] 15 1 5 Ship speed Propulsion power Full steaming 21-Jul 21-Jul 21-Jul 15 1 5 Propulsion power [kw] 12 1 8 6 4 2 Manoeuvring Open Loop Port approaching Open Loop. 4.5 9. 13.5 18.1 22.6 27.1 Ship's speed [Kts] Steaming Open Loop Fuel oil Type Marine fuel RMG 38 Density 15 C 981. kg/m 3 Viscosity 5 C 375 cst Water % Sulphur % 1.75 EGCS running hours [hr] 24 2 16 12 8 4 Steaming - Open Loop At berth - Closed Loop 1 8 6 4 2 OP/CL Ratio 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 Day of the month
EGCS in open loop mode - compliance monitoring Engine sulphur combustion chemistry: gas De-plume unit SO 2 CO 2 S + O2 SO2 ~ 95% SO2 + ½O2 SO3 ~ 5% SO x reactions in Open Loop: for SO 2 Scrubber unit SO 2 + H 2 O H 2 SO 3 H 2 SO 3 H + + HSO 3 - HSO 3 - H + + SO 3 2- PAH ph Tur. Sea Water SO 3 2- +.5 O 2 SO 4 2- PAH ph Tur. Wash Water gas Residence tank Cleaning unit Settling tank for SO 3 SO 3 + H 2 O H 2 SO 4 H 2 SO 4 + H 2 O HSO - 4 + H 3 O + HSO - 4 + H 2 O SO 2-4 + H 3 O +
emission in open loop mode CO 2 [%] 8 6 4 2 Scrubber unit No: 1 * CO 2 Faulty SO 2 indications * SO 2 4 2 SO 2 [ppm] CO 2 [%] 9 6 3 Scrubber unit No: 2 * CO 2 Faulty SO 2 indications * SO 2 4 2 SO 2 [ppm] -2 1 2 1-2 2 CO 2 [%] 1 8 6 4 Scrubber unit No: 3 * CO 2 6 4 2 SO 2 [ppm] CO 2 [ppm] 8 7 6 5 4 3 Scrubber unit No: 4 * CO 2 4 2 SO 2 [ppm] 2 2 1 Faulty SO 2 indications * SO 2 * SO 2-2 1 2 1-2
Sea and washwater parameters in open loop mode 1 8. 8 ph: 7.9 6. ph: 6.2 ph [-] 6 4 6 5 4 3 2 1 Sea Water ph [-] 4. 4 3 2 1 2 5.9 7.2 8.14 1 2 2. 5.8 6.175 6.55 6.925 7.3 1 2 4 1 8 Sea Water 3 6 4 PAH [µg/l] 2 2.1 9.1 18.1 27. EGCS Starting up 1 PAH: 2.2 1 2
Sea and washwater parameters in open loop mode Turbidity [NTU] 16 14 12 1 8 6 4 1 8 6 4 2 4 48 92 136 Sea Water EGCS Starting up 2 Turbidity: 6.2 1 2 Turbidity [NTU] 12 1 8 6 4 2 1 8 6 4 2 6. 29.75 53.5 77.25 Turbidity: 8.9 1 2
EGCS in closed loop mode - compliance monitoring gas SO x reactions in Closed Loop: SO 2 CO 2 for SO 2 De-plume unit Na + + OH - + SO 2 NaHSO 3 2Na + + 2OH - + SO 2 Na 2 SO 3 + H 2 O Scrubber unit 2Na + + 2OH - + SO 2 + 1/2 O 2 Na 2 SO 4 + H 2 O for SO 3 SO 3 + H 2 O H 2 SO 4 2NaOH + H 2 SO 4 Na 2 SO 4 + 2H 2 O Sea Water NaOH tank Sea Water PAH ph Tur. gas Process tank Holding tank PAH ph Tur. Separator Sludge tank
1221 emission and sea water parameters in closed loop mode Engine power [kw] 5 4 3 2 1 Rated power At berth Engine power: 122 kw 12 1 8 6 4 2 CO 2 [%] 15 12 9 6 3 Faulty SO 2 indications 15 1 5-5 -1-15 SO 2 [ppm] 1 2 * CO 2 * SO 2 1-2 2 1. 1 ph [-] 8. 6. 4. 2.. 2 15 1 5 ph: 6.9 5.2 6.2 7.2 8.2 9.2 Process Water 1 2 ph [-] 9 Sea Water ph: 6.3 6 * ph 3 Turbidity: 11.8 8 6 4 * Turbidity 2 1 2 Turbidity [NTU]
Conclusions 1. Hybrid EGCS performance measurements were carried out on board the ship during two month service operation period. 2. On average EGCS operation in open loop mode was 17 hrs at sea and 7 hrs a day in closed loop at port. 3. SO X and CO 2 emissions results are characterized by strong scattering of values, which in principle makes it impossible to assess compliance with the relevant limits, expressed in MEPC.184 (59) 29 guidelines. 4. Undoubtedly, this has to do with variable EGCS mode of operation, which is determined by the load of propulsion engines. 5. Sea water system exhibits much more stable parameters, qualifying for compliance assessment. Results of measurement of seawater parameters showed a slight lower ph value; 6.2 (OL) and 6.3 (CL) below the limit value 6.5. 6. No Turbidity of 8.9 NTU (OP) and 11.8 NTU (CL) over 25 NTU limit was exceeded. Survey period July August EGCS mode of operation Open Loop Closed Loop Open Loop Closed Loop EGCS runing hours [hr] 532 212 516 228 EGCS electric consumption [kwh] 397 81 78 591 385 844 84 513 EGCS fuel oil consumption [mt] 14.1 26.8 12.9 26.2 Total ship s fuel oil consumption [mt] 14 988 NaOH solution consumption [ltrs] 69 6875
Conclusions 1. The EGCS and related facilities introduce significant increases in electricity consumption, both: at sea and berth and this transfers into an increase in fuel consumption of 12.85 % of the total actual ship s flowrate. 2. The EGCS efficiency was estimated using the formula: ξ 1 = E SO2 E SO2 1% E SO2 and reached: 93.8 %. 3. Actual consumption of NaOH solution remains at 6.8 ltr/t of fuel oil. 4. The SOx emission for a ship equipped with EGCS was estimated at.47 g/kwh. 12 2. Scrubber efficiency [%] 1 8 6 4 2 6 5 4 3 2 1 SO 2 emission - [ppm] 1.26 43.1 84.94 Scrubber unit efficiency: 93.8% 1 2 3 4 SO 2 [g/kwh] 1.5 1..5 3 SO 2 specific emission [g/kwh] 25 2 15 1 5 -.165 1.1332 2.4313.4841 1.7823 SO 2 spec.:.47. 1 2 3 4 Engine power [kw] Engine power [kw]
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