METHOD FOR TREATING IMPURITIES CONTAINED IN EXHAUST GASES OF SHIPS, SHIP WITH EXHAUST GAS SCRUBBER, AND PURIFICATION UNIT
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Abstract
Method for treating impurities contained in exhaust gases of ships to reduce sulphur oxide and other emissions. In order for the method to purify wash water exiting from an exhaust gas scrubber sufficiently enough to be directly dischargeable to sea, and in order for a purification unit used to be small enough to be easily placed onboard a ship, exhaust gases are scrubbed in the exhaust gas scrubber and wash water containing impurities and exiting from the scrubber is supplied to the purification unit, circulated in an effluent circuit, and filtered through a semipermeable membrane of a filter to obtain purified effluent and a residue containing impurities, when necessary, the pH value of the purified effluent is adjusted to be at least 6.5, after which it is discharged into the sea or recycled to the scrubber while the residue containing impurities is led back to the effluent circuit.
11 Citations
40 Claims
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1-20. -20. (canceled)
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21. A method for treating impurities contained in exhaust gases of ships in order to reduce sulphur oxide emissions, the method comprising:
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scrubbing with water the exhaust gases in an exhaust gas scrubber in order to reduce sulphur dioxide emissions of the exhaust gases, supplying wash water to be purified, containing impurities and exiting from the exhaust gas scrubber, to a purification unit onboard a ship, the purification unit comprising an effluent circuit including at least one membrane filter, monitoring a pH value of the purified effluent, and if it is less than 6.5, it is adjusted to a value of at least 6.5, after which the purified effluent is discharged into a sea or returned to the exhaust gas scrubber, circulating the wash water to be purified, i.e. the effluent, in the effluent circuit, filtering the effluent through a semipermeable membrane of said membrane filter in order to achieve purified effluent and a residue containing impurities, and removing the purified effluent from said membrane filter and from circulation of the effluent circuit while the residue keeps on circulating in the effluent circuit. - View Dependent Claims (22, 23, 24, 25)
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- 26. A ship comprising an exhaust gas scrubber for scrubbing exhaust gases from the ship'"'"'s combustion engine and for reducing sulphur dioxide emissions, and a purification unit for purifying wash water to be purified and exiting from the exhaust gas scrubber, wherein the purification unit comprises an effluent circuit comprising a circulation pump and at least one membrane filter comprising a semipermeable membrane, the circulation pump being arranged to circulate the effluent to be purified in the effluent circuit by feeding effluent to an inlet end of said membrane filter such that effluent flowing through the membrane filter through the semipermeable membrane and exits, purified, from an outlet of said membrane filter and from the effluent circuit while a residue containing impurities is led from a discharge end of said membrane filter back to the circulation pump and from the circulation pump again to the inlet end of said membrane filter.
- 39. A purification unit for purifying polluted wash water, i.e. effluent, exiting from an exhaust gas scrubber of a ship, the purification unit being a transportable container-like unit comprising a first connecting means for connecting the purification unit to an effluent line coming from the exhaust gas scrubber of the ship, a second connecting means for connecting the purification unit to a water distribution circuit of the ship, and an outlet line for discharging from the purification unit the effluent purified therein, the effluent circuit comprising a circulation pump and at least one membrane filter comprising a semipermeable membrane, the circulation pump being arranged to circulate the effluent to be purified in the effluent circuit by feeding effluent to an inlet end of said membrane filter such that effluent flowing through said membrane filter through the semipermeable membrane and exits, purified, from an outlet of said membrane filter and from the effluent circuit while a residue containing impurities is led from a discharge end of said membrane filter back to the circulation pump and from the circulation pump again to the inlet end of said membrane filter.
Specification