# US 9,040,005 B2 · Scrubber system and method

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- Number: US 9,040,005 B2
- Document ID: US9040005B2
- Status: Granted
- Kind: B2
- Application number: 14/348,392
- Filed: 2012-09-12
- Published: 2014-09-04
- Granted: 2015-05-26
- Earliest claimed: 2011-09-30
- Assignees: Alfa Laval Corporate AB
- Applicants: Jens Peter Hansen
- Inventors: Jens Peter Hansen
- Web page: https://patentgrep.com/patent/US9040005B2

## CPC

- B01D 53/92: of engine exhaust gases (exhaust {or silencing} apparatus {for internal combustion engines, machines or engines in general}, having means for purifying, {rendering innocuous} or otherwise treating exhaust gases F01N3/00)
- B01D 47/00: Separating dispersed particles from gases, air or vapours by liquid as separating agent (B01D45/10 takes precedence; fractionating columns or parts thereof B01D3/16)
- B01D 53/1481: {Removing sulfur dioxide or sulfur trioxide}
- B01D 53/502: {characterised by a specific solution or suspension}
- B01D 53/504: {characterised by a specific device}
- B01D 53/75: Multi-step processes
- F01N 3/04: using liquids
- F01N 13/004: {specially adapted for marine propulsion, i.e. for receiving simultaneously engine exhaust gases and engine cooling water (for submerged exhausting F01N13/12; treating exhaust by using liquids F01N3/04)}
- B01D 2247/04: Regenerating the washing fluid
- B01D 2247/107: using an unstructured demister, e.g. a wire mesh demister
- B01D 2251/304: of sodium
- B01D 2251/604: Hydroxides
- B01D 2251/606: Carbonates
- B01D 2252/103: Water
- B01D 2252/1035: Sea water
- B01D 2257/302: Sulfur oxides
- B01D 2257/60: Heavy metals or heavy metal compounds
- B01D 2258/0283: Flue gases
- B01D 2259/4566: for use in transportation means
- F01N 2570/04: Sulfur or sulfur oxides
- F01N 2590/02: for marine vessels or naval applications
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02T 10/12: Improving ICE efficiencies
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

The present invention relates to a method for removal of SO2 from exhaust gas from a marine engine or a marine boiler of a ship. The exhaust gas from said marine engine or marine boiler is cooled and washed with seawater in a first scrubber section, and subsequently, in a second scrubber section, washed with circulating freshwater with an addition of an alkaline chemical. The circulating freshwater used for washing is warmer than the seawater used for cooling in the first scrubber section. The warmer freshwater is indirectly heat exchanged with cold seawater. The exhaust gas washed in the first scrubber section is passed via a demister unit before it is washed with circulating freshwater in the second scrubber section. The invention further relates to a corresponding scrubber system.

## Claims

### Claim 1

A method for removal of SO2 from exhaust gas from a marine engine or a marine boiler of a ship, wherein the exhaust gas from said marine engine or marine boiler in a first scrubber section is cooled and washed with seawater, and subsequently in a second scrubber section is washed with circulating freshwater with an addition of an alkaline chemical, the circulating freshwater used for washing being warmer than the seawater used for cooling, and wherein the warmer freshwater is indirectly heat exchanged with cold seawater, the method further comprising passing the exhaust gas washed in the first scrubber section via a demister unit before it is washed with circulating freshwater in the second scrubber section.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the supply of seawater to the first scrubber section is temporarily stopped or reduced, while continuing washing the exhaust gas with circulating freshwater in the second scrubber section.

### Claim 3 (depends on 1)

A method according to claim 1, comprising the step of cleaning the circulating freshwater in a water cleaning unit before being discharged.

### Claim 4 (depends on 1)

A method according to claim 1, wherein the alkaline chemical is sodium hydroxide (NaOH), sodium carbonate (Na2CO3) or sodium bicarbonate (NaHCO3).

### Claim 5

A scrubber system for removal of SO2 from exhaust gas from a marine engine or a marine boiler of a ship, wherein the scrubber system comprises a heat exchanger and a first scrubber section arranged in communication with a second scrubber section, wherein exhaust gas from said marine engine or marine boiler is arranged to be supplied to the first scrubber section to be cooled and washed with seawater to be supplied to the first scrubber section, and wherein the thus washed and cooled exhaust gas is arranged to be supplied to the second scrubber section to be washed with circulating freshwater with an addition of an alkaline chemical to be supplied to the second scrubber section, the circulating freshwater used for washing being warmer than the seawater used for cooling, and wherein the warmer freshwater is arranged to be indirectly heat exchanged with cold seawater by the heat exchanger, the system further comprising a demister unit through which the exhaust gas washed in the first scrubber section is arranged to be passed before it is washed with circulating freshwater in the second scrubber section.

### Claim 6 (depends on 5)

Scrubber system according to claim 5, further comprising a plurality of valves, whereby the supply of seawater to the first scrubber section can be temporarily stopped or reduced by said valves during continued washing of the exhaust gas with circulating freshwater in the second scrubber section.

### Claim 7 (depends on 5)

Scrubber system according to claim 5, wherein the demister unit is arranged between the outlet of the first scrubber section and the inlet of the second scrubbers section.