KR200493729Y1 - Cleaning system, method and use - Google Patents

Abstract

A purification system 0 and a method for the reduction of particulate matter and SOx in exhaust gases from a marine combustion engine 2 are provided with the use of such a system. The purification system comprises a closed first scrubber process loop (4) comprising a first scrubber section (10), an open second scrubber process loop (6) comprising a second scrubber section (34), and a water purification unit (8). ). Exhaust gas is supplied through the first and second scrubber compartments. Seawater is recycled in the first scrubber section to absorb particulate matter contained in the exhaust gas into the seawater. Seawater is supplied through the second scrubber section to absorb SOx contained in the exhaust gas into the seawater. The flow of seawater from the first scrubber process loop is purified by a water purification unit prior to discharge.

Description

Purification system, method and use {CLEANING SYSTEM, METHOD AND USE}

The present invention relates to a purification system and method for reducing SOx and particulate matter in exhaust gases from marine combustion engines, burners or boilers. The invention also relates to the use of such a system.

During the combustion of fossil fuels, sulfur in the fuel is released in the form of _{sulfur oxides (SO x ).} Other contaminants in the combustion gases are soot, oil, heavy metal particles and primary particulate matter such as _{nitrogen oxides (NO x ).} It is well known that air pollution seriously affects human health and the environment. It is also well known that oxides of sulfur and oxides of nitrogen are the main precursors of acid rain.

The current regulations on emission control of international shipping include an upper limit on the sulfur content of fuel oils as a means to control _{SO x emissions.} There are special fuel-quality provisions for SOx in the field of emission control, and the permitted fuel sulfur limit is expected to decrease substantially in the near future. The MARPOL Annex VI Act, which came into force in May 2005 in accordance with regulations from several European Union directives, suppresses the effects of marine diesel on the environment. As a result, strict sulfur regulations were introduced around the Nordic and US coastlines in 2015, and global restrictions are expected in 2020.

There are different emission reduction possibilities that can be used alone or in combination. One possibility is to use cleaner fuels such as distillate fuels or low sulfur fuels. Another possibility is to use a combination of seawater or freshwater and an alkaline agent such as NaOH to apply a method of controlling the emissions of _{SO x, such as wet scrubber technology typically used on ships.} Another alternative is the dry scrubber technique using a ceramic membrane or granules of hydrated lime [Ca(OH) _{2 ].}

It is well known in the marine industry today to apply Exhaust Gas Cleaning (EGC) to reduce _{SO x} in exhaust gases from ship engines.

One well-known wet scrubber of the EGC type is the so-called closed water, which uses circulating fresh water in combination with an alkaline agent such _{as sodium hydroxide (NaOH) or sodium carbonate (Na 2} CO _{3) to clean sulfur oxides and soot particles from the exhaust gas.} It is an expression loop scrubber. In order to control the quality of circulating fresh water, a small amount of circulating fresh water may be replaced with clean fresh water intermittently or continuously, and stored on a ship or discharged offboard after purification.

Although scrubbers of the type mentioned above are commonly used, some unresolved or problematic issues still exist. Due to evaporation, the water consumption of closed-loop scrubber systems is generally too high, requiring a large amount of fresh water to be added continuously to the system to maintain balance. Additionally, water purification is important in closed loop scrubber systems. If the water is too dirty, it can be difficult to avoid the build-up of soot inside the scrubber, which is not allowed to discharge, and eventually clogs the valves and nozzles and may cause malfunction of the scrubber system components. In addition, _{the consumption of pH neutralizing compounds such as NaOH or Na 2} CO ₃ is so high that it is expensive to operate the scrubber system.

EP 1 857 169 A1 discloses a freshwater scrubber system comprising a two compartment scrubber, wherein the first compartment is for sulfur removal and the second compartment is for condensation.

Another well-known wet scrubber of the EGC type is a so-called open loop scrubber, which uses the natural alkalinity of seawater to clean sulfur oxides and soot particles from the exhaust gas. The sea water is then supplied from the sea through a scrubber to absorb _{SO x and particulate matter into the sea water before being discharged directly back into the sea.}

Although these open loop scrubbers are commonly used, some problematic environmental issues still exist. For example, particulate matter absorbed in seawater discharged from the scrubber may cause harm to the local environment.

There are several options to solve this problem. In one known system, seawater is pumped through a hydro cyclone to remove contaminants prior to discharge. The downside of this system is both that it is very large and it requires a large amount of energy to run the pump.

It is an object of the present invention to provide the possibility of purifying ship exhaust gases by means of seawater having a reduced turbidity, ie a reduced amount of particulate matter in the seawater to be discharged compared to the prior art.

The purification systems and methods for achieving the above object, as well as the use of such purification systems, are defined in the appended claims and discussed below.

The purification system according to the invention is arranged for the reduction of SOx and particulate matter in exhaust gases from marine combustion engines, burners or boilers. The purification system includes a closed first scrubber process loop, a water purification unit and an open second scrubber process loop. The first scrubber process loop includes a first scrubber section and a circulation pump arranged to recirculate seawater within and through the first scrubber process loop. The first inlet of the first scrubber section allows the introduction of the exhaust gas into the first scrubber section and allows contact between the exhaust gas and seawater recirculating through the first scrubber section to absorb particulate matter into the recirculating seawater. It is connectable to a marine combustion engine, burner or boiler to obtain the purified and cooled exhaust gas. The first scrubber process loop is connectable to the first seawater supply to allow flow of seawater to the first scrubber process loop. The inlet of the water purification unit communicates with the first scrubber process loop to allow flow of seawater from the first scrubber process loop to the water purification unit for purification before discharge. The second scrubber process loop is connectable to the second seawater supply unit. The second scrubber process loop includes a second scrubber section and a feed pump arranged to supply sea water from the second sea water supply in and through the second scrubber section in the second scrubber process loop. The outlet of the second scrubber section is arranged to discharge seawater from the second scrubber section. The purification system further includes a communication portion between the first and second scrubber sections. The communication section is to allow the transfer of the partially purified and cooled exhaust gas from the first scrubber section to the second scrubber section and absorb SOx in the partially purified and cooled exhaust gas and seawater supplied through the second scrubber section. Further purified exhaust gas is obtained by enabling contact between seawater supplied through the second scrubber section.

The first scrubber process loop is closed, meaning that the inlet of the first scrubber section is connected, directly or indirectly, with the outlet of the first scrubber section so that seawater is recycled through the first scrubber section. In contrast, the second scrubber process loop is open, meaning that it is arranged to supply seawater through the second scrubber section only once before seawater discharge, which requires no inlet-outlet connection.

Thus, the purification system of the present invention has two scrubber process loops, each comprising a separate scrubber section. Exhaust gas will be supplied first through the first scrubber section and then through the second scrubber section. Most of the particulate matter contained in the exhaust gas will be absorbed by the recirculating seawater within the first scrubber section, ie the first scrubber process loop. The seawater in the first scrubber process loop is recycled multiple times through the first scrubber section, which will thus transform the recycled seawater into a considerably soot and oil-contaminated black liquid. Since the purification system includes a water purification unit, it is possible to purify dirty seawater drained from the first scrubber process loop. Exhaust gases typically have high levels of SO _x . Thus, the pH of the seawater recirculating within the first scrubber process loop will typically drop to a value below 3. Seawater with such a low pH _{does not essentially absorb SO x} , which makes the first scrubber process loop primarily dedicated to the removal of particulate matter from the exhaust gas.

Also, the temperature of the exhaust gas is typically high. Thus, the seawater recirculating through the first scrubber section will be heated, as a result of which the water evaporates and thus the concentration of soot, oil and salt in the recirculating seawater in the first scrubber process loop increases. Since the first scrubber process loop is connectable to the first seawater supply unit, it is possible to replenish seawater to compensate for evaporated water as well as dirty seawater drained for purification in the water purification unit.

Because of the first process loop, the second scrubber process loop will be essentially free of soot and oil particulates, i.e., has a low turbidity, which absorbs the seawater supplied through the second scrubber section so that the _{SO x contained in the exhaust gas is cleaned.} It makes it possible to use, and there is no need to worry about undesired soot and oil absorption of the seawater, which will result in an increase in turbidity of the seawater to be discharged from the second scrubber section.

An advantage of the purification system of the present invention is that the flow of seawater to be purified in the water purification unit can be relatively small compared to the total seawater flow into the purification system, although it still contains most of the particulate matter from the exhaust gas. As a result, it will be much easier to construct an efficient and compact water purification unit.

The purification system may further include a mixing chamber. The second inlet of the mixing chamber can communicate with the outlet of the second scrubber section to allow flow of seawater from the second scrubber section to the mixing chamber. Additionally, the first inlet of the mixing chamber can communicate with the first outlet of the water purification unit to allow flow of purified seawater from the water purification unit to the mixing chamber. The mixing chamber may further comprise an outlet for discharging a mixture of purified water and seawater from the second scrubber section.

The concentration of particulate matter in seawater exiting the water purification unit may change over time. For example, the concentration may be higher with respect to abnormal water purification unit operation, such as during a start, stop or self-cleaning sequence. The provision of a mixing chamber, and thus the possibility of mixing the seawater from the water purification unit with the seawater of low turbidity before discharge from the second scrubber section, makes it possible to keep the turbidity value of the seawater discharged from the purification system as low and uniform as possible. do.

The purification system may allow the first scrubber process loop to further comprise a circulation tank arranged to contain recirculating seawater within the first scrubber process loop. The inlet of the circulation tank can communicate with the outlet of the first scrubber section to allow flow of seawater from the first scrubber section to the circulation tank. The first outlet of the circulation tank can communicate with a second inlet of the first scrubber section to allow flow of seawater from the circulation tank to the first scrubber section.

The circulation tank may be configured to receive seawater to be recycled within the first scrubber process loop while the purification system is stopped. The circulation tank may further be arranged to serve as a settling tank for seawater before the seawater is supplied to the water purification unit.

The purification system may further include a first heat exchanger arranged between the first scrubber process loop and the water purification unit and arranged to cool seawater flowing from the first scrubber process loop to the water purification unit. The first heat exchanger may be arranged to maintain the temperature of seawater flowing from the first scrubber process loop to the water purification unit in the range of 0°C to 50°C, and preferably 5°C to 35°C.

The chloride content of seawater is relatively high, which makes seawater, especially warm seawater, corrosive. By cooling the seawater, the corrosiveness of the seawater is reduced, thereby reducing the corrosive wear of the metal used in the water purification unit and the piping connected thereto.

The purification system may further comprise a compound dosing unit arranged between the first scrubber process loop and the water purification unit. The compound administration unit may be arranged to add an alkaline compound to seawater flowing from the first scrubber process loop to the water purification unit. The compound administration unit may be arranged to maintain the pH value of seawater flowing from the first scrubber process loop to the water purification unit in the range of 3 to 10, and preferably 6 to 8.

As mentioned above, _{due to the high level of SO x} in the exhaust gas, the seawater recirculating within the first scrubber process loop will have a low pH. Low pH makes sea water more corrosive. In addition, due to the equipotential charge of the soot/oil particulates, purification of seawater is easier when the pH is close to 7 than when it is at a lower pH. The advantage of adjusting the pH after the seawater exits the first scrubber process loop is that the seawater _{can no longer absorb SO x} from the exhaust gas at this time, which allows a significant limitation of the consumption of alkaline compounds. As a result, the alkaline compound consumption can be less than 10% of that of a conventional closed loop scrubber system.

The purification system may further include a second heat exchanger arranged to cool the seawater recirculating within the first scrubber process loop. The second heat exchanger may be arranged to maintain the temperature of the seawater to be received by the first scrubber section in the range of 0°C to 50°C, and preferably 5°C to 35°C.

When reducing the temperature of the seawater recirculating within the first scrubber process loop, evaporation in the first scrubber section will be reduced, which increases the number of seawater recirculation and thus from the first scrubber process loop to the water purification unit. It will reduce the required seawater flow. It should be understood that the lowest possible temperature within this range will provide the best performance.

The purification system may further include a communication between the second scrubber process loop and the first scrubber process loop, arranged to provide sea water from the second scrubber process loop to the first scrubber process loop. Thus, the first seawater supply and the second seawater supply will be one and the same seawater supply, which makes the purification system less complex.

The purification system comprises a demister in which the communication portion between the first and second scrubber compartments is arranged to allow passage of gas from the first scrubber compartment to the second scrubber compartment while retaining the liquid in the first scrubber compartment. You may want to include it additionally.

The liquid is condensate from the exhaust gas and/or sea water droplets sucked with the exhaust gas, the latter further limiting the soot and oil load in the second scrubber section.

The method according to the invention is to reduce SOx and particulate matter in exhaust gases from marine combustion engines, burners or boilers. The method includes the following steps (does not have to be executed in the order below, some of which may be performed simultaneously):

Recirculating seawater within the closed first scrubber process loop and through the first scrubber section included in the first scrubber process loop,

A marine combustion engine, burner or in the first scrubber section to enable contact between the recirculating seawater and the exhaust gas through the first scrubber section to obtain the partially purified and cooled exhaust gas to absorb particulate matter in the recirculating seawater. Introducing exhaust gas from the boiler,

Supplying a flow of seawater from the first seawater supply unit to the first scrubber process loop,

Supplying a flow of seawater from the first scrubber process loop to the water purification unit for purification before discharge,

Supplying seawater from the second seawater supply unit in the open second scrubber process loop and through the second scrubber section included in the second scrubber process loop,

Discharging seawater from the second scrubber section, and

Partially to enable contact between the seawater supplied through the second scrubber compartment and the partially purified and cooled exhaust gas to absorb SOx in the seawater supplied through the second scrubber compartment, thereby obtaining additionally purified exhaust gas. Delivering the purified and cooled exhaust gas from the first scrubber section to the second scrubber section.

The method comprises 2 to 40 times through the first scrubber section, so as to limit the flow to the water purification unit to less than 5% of the total seawater flow through the first and second scrubber sections, prior to supplying seawater to the water purification unit. And preferably it may include the step of recycling 10 to 20 times.

The method comprises the steps of supplying a flow of seawater from the second scrubber section to the mixing chamber, supplying a flow of purified seawater from the water purification unit to the mixing chamber, and discharging a mixture of the purified water and seawater from the second scrubber section. It may include steps.

The method may include supplying seawater to the first scrubber process loop from the second scrubber process loop, upstream or downstream of the second scrubber section, and the first seawater supply unit and the second seawater supply unit are one and the same seawater supply unit. .

The method may comprise cooling the seawater flowing from the first scrubber process loop to the water purification unit to a temperature in the range of 0 to 50°C, and preferably 5 to 35°C.

The method may comprise supplying an alkaline compound to the seawater of the first scrubber process loop so that the seawater flowing from the first scrubber process loop to the water purification unit has a pH in the range of 3-10, and preferably 6-8. have.

The method may comprise cooling the recirculating seawater in the first scrubber process loop such that the seawater to be received by the first scrubber section is maintained at a temperature of 0 to 50°C, and preferably 5 to 35°C.

The method is based on a purification system having essentially the same configuration as the purification system described above, and thus the same advantages are provided by different embodiments, and reference is made to the above section to avoid excessive repetition.

The use according to the invention relates to the use of said purification system on a ship for the purpose of reducing SOx and particulate matter in exhaust gases from marine combustion engines, burners or boilers.

The above-described advantages of the different embodiments of the purification system of the present invention can be transferred naturally to the method of the present invention and the use according to the present invention.

Still other advantages, objects, features and aspects of the present invention will become apparent from the drawings as well as from the detailed description below.

The invention will now be described in more detail with reference to the accompanying schematic diagram.
1 shows a purification system according to the present invention.

In Fig. 1 a purification system 0 is shown. The purification system is used on a ship to purify exhaust gases from the combustion engine 2. More specifically, the purification system 0 is arranged to remove particulate matter such as soot and oil particulates, and acidic gases such as SOx from the exhaust gas by flushing the exhaust gas with sea water.

As further explained below, the particulate matter is removed from the exhaust gas by dissolving in sea water, and then separated from the exhaust gas. In addition, SOx is removed from the exhaust gas by washing it with more seawater, in this process the natural alkalinity of the seawater is used to absorb SOx from the exhaust gas and bind it to the seawater.

The purification system 0 comprises a closed first scrubber process loop 4, an open second scrubber process loop 6 and a water cleaning unit in the form of a separator for purifying a portion of the seawater before the seawater is discharged. WCU)](8). The purification system (0) should be considered a combination of open/closed loop seawater scrubber systems. It is operated with seawater with a continuous supply of fresh seawater. It should be understood that the seawater used in the first scrubber process loop is used more than once before being replaced with fresh seawater, which is not true for the seawater used in the second scrubber process loop, which is used only once before being replaced.

The first scrubber process loop 4 comprises a first scrubber section 10 of the scrubber 11, a circulation tank 12 arranged to receive seawater, a circulation pump 14 and a second heat exchanger 16. . The first inlet 18 of the first scrubber section 10 is connected to the combustion engine 2 to receive exhaust gases from the combustion engine. In addition, the outlet 20 of the first scrubber section 10 is connected to the inlet 22 of the circulation tank 12, and the first outlet 30 of the circulation tank 12 is a second inlet of the first scrubber section. Connected to (32). The circulation pump 14 is arranged between the circulation tank and the second heat exchanger 16, and the second heat exchanger is again arranged between the first scrubber section and the circulation pump. The circulation pump 14 is arranged to recirculate seawater in the first scrubber process loop 4 and thus through the first scrubber section 10.

The second scrubber process loop 6 comprises a second scrubber section 34 of the scrubber 11, a feed pump 36 and an inlet water analyzer 38. The inlet 40 of the second scrubber section is connected to the sea water supply unit 42, and the outlet 44 of the second scrubber section is arranged for seawater discharge. The feed pump 36 is arranged between the sea water supply 42 and the inlet water analyzer 38, and the inlet water analyzer is again arranged between the second scrubber section 34 and the feed pump 36. The feed pump 36 is arranged to supply seawater from the sea in the second scrubber process loop 6 and thus through the second scrubber section 34. The purification system 0 comprises a communication part 60 in the form of a pipe, for example, between the first and second scrubber process loops, and a water filter 62 arranged in the communication part 60. The feed pump 36 is arranged to supply sea water from the sea and to the first scrubber process loop 4 through the communication part 60 and the water filter 62. Seawater supplied from the sea to the purification system (0) is subjected to water quality control by an inlet water analyzer (38).

The second outlet 46 of the circulation tank 12 is connected to the inlet 48 of the WCU 8. The purification system 0 further comprises a first heat exchanger 50 and a compound dosing unit 52 for supplying an alkaline agent to the seawater to be purified by the WCU 8. The first heat exchanger 50 is arranged between the circulation tank 12 and the compound dosing unit 52, and the compound dosing unit is arranged between the first heat exchanger and the WCU 8.

The purification system (0) comprises a mixing chamber (54), an outlet water analyzer (56) arranged downstream of the mixing chamber, a sludge tank (58) and a communication part (59) connecting the first and second scrubber compartments (10, 34). ) Additionally. The first outlet 64 of the WCU 8 is connected to the sludge tank 58 while the second outlet 66 of the WCU is connected to the first inlet 68 of the mixing chamber 54. Further, the outlet 44 of the second scrubber section 34 is connected to the second inlet 70 of the mixing chamber 54. The outlet 72 of the mixing chamber is arranged for discharge into the sea.

The components of the purification system 0 are connected and communicated with each other by means of suitable piping.

In the following, the operation of the purification system and thus the method of the present invention for purifying exhaust gases from the engine 2 will be further described.

The hot and dirty exhaust gas having a temperature of approximately 180-350° C. is supplied from the engine 2 through the first scrubber section 10. Seawater supplied to the first scrubber section 10 is dispersed therein through a plurality of nozzles (not shown). Inside the first scrubber section, the exhaust gas contacts seawater circulating through the first scrubber process loop 4. When seawater encounters high-temperature exhaust gas, a large amount of seawater evaporates into water vapor and at the same time the temperature of the exhaust gas decreases. It should be understood that evaporation should not be perfect, and this can be ensured by sufficient water flow within the first scrubber process loop. As an example, the degree of evaporation may be that at least 80 to 90% of seawater accommodated in the first scrubber section is not evaporated and remains in a liquid form. In addition, when seawater meets the exhaust gas, most of the oil, soot and other particulate matter contained in the exhaust gas will be absorbed by the circulating seawater, and the circulating seawater will become more and more dirty, i.e., contaminated with soot and oil. . Thus, the first scrubber section 10 should be considered a soot and oil scrubbing step. In order to stably maintain the level of salt, soot, oil and other particulate matter in the seawater, the seawater is purified through the circulation tank 12 and through the first scrubber process loop before being discharged to the WCU 8 for final discharge. It is recycled 10 to 20 times. For example, the degree of salinity in recycled seawater should be 20% or less, and the total amount of suspended solids should be 5% or less.

Discharge to the WCU 8 can take place in a continuous or discontinuous manner. In order to compensate for the discharged seawater as well as the water evaporated in the first scrubber process loop, the first scrubber process loop is replenished with fresh seawater. Replenishment is made through the communication unit 60, as described above. As a result of the high SOx content in the exhaust gas, the circulating seawater will have a pH value below 4. As a result of the low pH, the absorption of SOx from the exhaust gas in the first scrubber section will be kept to a minimum. More specifically, less than 10% of the total available SOx in the exhaust gas will be absorbed by the recirculating seawater within the first scrubber process loop.

The second heat exchanger 16, which uses seawater provided through a pipe (not initiated) in the ship as a refrigerant, evaporates in the first scrubber section 10 and, accordingly, a first scrubber process to reduce the amount of seawater replenishment required. Seawater circulating in the loop 4 is cooled to a temperature of 5 to 35°C. If the second heat exchanger 16 was not present, the seawater recycled in the first scrubber process loop would have a balanced temperature of 40 to 70° C. as a result of heat exchange with the exhaust gas inside the first scrubber section.

The first heat exchanger 50, which also uses seawater provided through a pipe (not initiated) in the hull, as a refrigerant, has the corrosiveness of the dirty seawater discharged from the first scrubber process loop 4 before entering the WCU. Cool to a temperature of 5 to 35 ℃ to reduce the. In addition, the compound administration unit 52 supplies an alkaline agent in the form of NaOH to increase its pH to a value of 6 to 8 before the seawater enters the WCU. This is to improve the purification efficiency of the WCU and further reduce the corrosiveness of seawater.

The WCU 8 separates the dirty seawater into a first sludge fraction containing soot, oil and other particulate matter, and a second fraction containing residual water, that is, purified seawater. The sludge produced by the WCU is collected in a sludge tank 58 for later controlled discharge, such as during port shutdown. The residual water is supplied to the mixing chamber 54.

The exhaust gas is cooled and partially purified in the first scrubber section 10, and then supplied through the second scrubber section 34 via a communication section 59. The communication portion may include a demister that allows passage of gas while retaining soot and oil contaminated water in the first scrubber compartment. Seawater supplied to the second scrubber section 34 is dispersed therein through a plurality of nozzles (not shown). The exhaust gas partially purified inside the second scrubber section comes into contact with seawater supplied through the second scrubber process loop 6. Due to the natural alkalinity of seawater, SOx contained in the exhaust gas reacts with seawater and is absorbed therein in the form of sulfates and sulfites. Therefore, the second scrubber section 34 should be considered an SOx scrubbing step. Seawater is then discharged from the second scrubber section 34 through the outlet 44 and supplied to the mixing chamber 54.

The residual water from the WCU 8 in the mixing chamber 54 is mixed with seawater discharged from the second scrubber section 34 to form a mixture discharged from the mixing chamber 54 to the sea. Before being discharged to sea, the mixture is subjected to water quality control by an outlet water analyzer (56). The quality of the mixture seawater is as described above, to verify that the mixture quality meets established discharge criteria for maximum levels of, for example, polyaromatic oils, suspended solids and acidity, also known as PAH, pH and turbidity. Likewise, the quality of seawater supplied to the purification system 0 controlled by the inlet water analyzer 38 is compared.

After further purification in the second scrubber section 34, the exhaust gas is passed through the demister 76, which allows the gas to pass but the liquid retains in the second scrubber section, and then through the exhaust gas outlet 74. Exit the purification system (0). These liquids are water droplets condensed from seawater or humid exhaust gases.

To give an idea of the seawater flowing in the first and second scrubber process loops 4, 6, the following non-constraining examples are provided. This example is based on computer-run simulations.

During operation of the 12MW engine, the circulating seawater flow in the first scrubber process loop is 120 m ³ /h, and the seawater flow through the second scrubber process loop is 540 m ³ /h.

With the exhaust gas inlet temperature of 350°C, the seawater temperature circulating in the first scrubber process loop will be stable at 60°C (there is no heat exchanger in the first scrubber process loop), and has an evaporation rate of ^{5 m 3 /h.} . The flow to the water purification unit 20 ^{was set to 6 m 3} /h, and the replenishment rate of seawater in the first scrubber process loop ^{was given as 11 m 3} /h, so the total seawater flow would be 551 m ³ /h. Seawater in the first scrubber process loop will therefore experience an average of 20 recycles before being discharged. With an initial salinity of 3.5% of the incoming seawater, the seawater circulating in the first scrubber process loop will eventually have a salinity of 6% and a pH of 2. The consumption of NaOH for neutralization before the seawater discharged from the first scrubber process loop was supplied to the WCU was calculated as 2 kg/h, which corresponds to approximately 1% of the consumption of comparable conventional closed loop scrubbers.

The purification system 0 according to the present invention has the main advantage of being able to reduce the overall turbidity of the effluent without a effluent purification unit compared to a conventional open loop system.

Another advantage of the purification system (0) is that the flow of water through the water purification unit is less than 5% of the total seawater flow into the scrubber, while retaining the same advantage as compared to a conventional open loop scrubber with a full effluent purification unit. It can be reduced.

Another advantage of the purification system (0) is that of a closed loop system where the consumption of alkaline compounds can be compared, while retaining the same possibility for water purification, compared to a conventional closed loop scrubber with a complete effluent purification. It can be reduced to less than %.

The present invention is not limited to the embodiments described above and shown in the drawings, but may be supplemented and modified in any manner within the scope of the present invention as defined in the accompanying claims.

In one embodiment an arrangement for supplying a coagulant (not initiated) may be arranged at a location between the first scrubber process loop 4 and the WCU 8. Coagulants, typically in the form of trivalent metal ions, such as aluminum or iron, can be used to improve the performance of the WCU, whereby the particulate matter forms a chemical compound linked to the metal salt. These chemical compounds are heavier and easier to separate by water purification units than "free" particulate matter.

The purification system 0 shown in the figure includes a water filter 62 for removal of particulate matter from seawater supplied to the first scrubber process loop to reduce the volume of sludge produced by the WCU. Alternative embodiments of the purification system may lack such a water filter.

In the purification system 0 shown in the figure, the residual water from the WCU and the seawater discharged from the second scrubber process loop are mixed before being discharged to the sea as well. The purification system according to an alternative embodiment may lack the mixing chamber 54, and therefore the residual water from the WCU and seawater discharged from the second scrubber process possibly to ensure that the current discharge laws are satisfied. After quality measurements have been made, they can be individually released into the sea.

In the purification system 0 shown in the figure, the first and second scrubber process loops are connected to enable supply of seawater from the second scrubber process loop to the first scrubber process loop, and the first and second process loops Seawater supplied to the seawater is supplied from one and the same seawater supply. According to an alternative embodiment of the purification system of the present invention, the first and second scrubber process loops may be completely separated and seawater may be supplied from the separated seawater supply unit.

The communication portion between the first and second scrubber process loops need not extend as shown in the figure. According to an alternative embodiment, the communication part extends from the second scrubber process loop to the first scrubber process loop from between the mixing chamber 54 and the outlet 44 of the second scrubber section 34.

Instead of being a separator, the WCU may comprise a hydrocyclone, a membrane filter, or a combination thereof.

The first and second heat exchangers described above may be of any type of suitable heat exchanger, such as a plate heat exchanger. The heat exchangers can use any suitable refrigerant, and seawater is just an example.

NaOH and other alkaline agents, e.g., Na ₂ CO ₃ , can be supplied by the compound dosing unit 52, which unit is different from that shown in the figure in an alternative embodiment, e.g., a first heat exchanger. It can be located between the air and the circulation tank.

The purification system of the present invention does not need to include a circulation tank.

Claims (12)

A purification system (0) for reducing SOx and particulate matter in exhaust gases from a marine combustion engine (2), a burner or a boiler, the purification system comprising:
A closed first scrubber process loop (4), a first scrubber section (10) and a circulation pump (14) arranged to recirculate seawater in and through the first scrubber section, a first scrubber Comprising a first inlet (18) of the compartment, the first inlet allowing the introduction of exhaust gas into the first scrubber compartment and recirculating seawater and exhaust gas through the first scrubber compartment for absorption of particulate matter into the recirculating seawater The first seawater supply 42 is connectable to a marine combustion engine, burner or boiler to enable contact between to obtain a partially purified and cooled exhaust gas, and to allow the flow of seawater to the first scrubber process loop. A closed first scrubber process loop 4 connectable to,
A water purification unit 8, an inlet 48 of the water purification unit in communication with the first scrubber process loop to allow flow of seawater from the first scrubber process loop to the water purification unit for purification before discharge,
As an open second scrubber process loop 6 connectable to the second seawater supply part 42, seawater is collected in the second scrubber process loop and through the second scrubber section from the second scrubber section 34 and the second seawater supply section. An open second scrubber process loop (6) comprising a feed pump (36) arranged to feed, an outlet (44) of a second scrubber section arranged for discharge of seawater from the second scrubber section,
As the communication part 59, a second scrubber compartment is provided to allow the delivery of partially purified and cooled exhaust gas from the first scrubber compartment to the second scrubber compartment and to absorb SOx in the seawater supplied through the second scrubber compartment. It includes a communication portion 59 positioned between the first scrubber section and the second scrubber section to enable contact between the seawater supplied through and the partially purified and cooled exhaust gas to obtain additionally purified exhaust gas. That, the purification system (0). The second inlet (70) of the mixing chamber (54), in communication with the outlet (44) of the second scrubber section (34) to allow flow of seawater from the second scrubber section to the mixing chamber. ), and a first inlet 68 of the mixing chamber in communication with the first outlet 66 of the water purification unit 8 to allow the flow of purified seawater from the water purification unit to the mixing chamber, The mixing chamber further comprises an outlet 72 for discharging a mixture of purified water and seawater from the second scrubber section. The circulation tank (12) according to claim 1 or 2, wherein the first scrubber process loop (4) is arranged to contain seawater recirculating within the first scrubber process loop, seawater from the first scrubber section to the circulation tank. The inlet 22 of the circulation tank in communication with the outlet 20 of the first scrubber section 10 to allow the flow of, and the first scrubber section to allow the flow of seawater from the circulation tank to the first scrubber section. 2 Purification system (0) comprising a first outlet (30) of a circulation tank in communication with an inlet (32). The first heat exchange according to claim 1 or 2, arranged between the first scrubber process loop (4) and the water purification unit (8) and arranged to cool the seawater flowing from the first scrubber process loop to the water purification unit. Purification system (0), further comprising a group (50). The temperature of the seawater flowing from the first scrubber process loop (4) to the water purification unit (8) in the range of 0°C to 50°C, or 5°C to 35°C according to claim 4, according to claim 4, wherein Purification system 0, arranged to retain. The method according to claim 1 or 2, arranged between the first scrubber process loop (4) and the water purification unit (8) and arranged to add an alkaline compound to the seawater flowing from the first scrubber process loop to the water purification unit. Purification system (0), further comprising a compound administration unit (52). The method according to claim 6, wherein the compound administration unit (52) is arranged to maintain the pH value of seawater flowing from the first scrubber process loop (4) to the water purification unit (8) in the range of 3 to 10, or 6 to 8. , Purification system (0). Purification system according to claim 1 or 2, wherein the first scrubber process loop (4) comprises a second heat exchanger (16) arranged to cool the seawater recirculating within the first scrubber process loop (4). (0). The purification system according to claim 8, wherein the second heat exchanger (16) is arranged to maintain the temperature of the seawater to be received by the first scrubber section (10) in the range of 0°C to 50°C, or 5°C to 35°C. (0). The communication part according to claim 1 or 2, arranged between the second scrubber process loop (6) and the first scrubber process loop (4) to supply seawater from the second scrubber process loop to the first scrubber process loop ( 60), wherein the first seawater supply unit and the second seawater supply unit are one and the same seawater supply unit 42, a purification system (0). The communication part (59) between the first and second scrubber compartments (10, 34) according to claim 1 or 2, wherein the liquid is retained in the first scrubber compartment, while the liquid is retained in the first scrubber compartment, from the first scrubber compartment to the second scrubber compartment. A purification system (0) comprising a demister arranged to allow a passage of gas in the. 3. Purification system (0) according to claim 1 or 2, used on ships for the purpose of reducing SOx and particulate matter in exhaust gases from marine combustion engines (2), burners or boilers.

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