FI130440B

FI130440B - Method for recovering of carbon dioxide from marine vessel exhaust gases

Info

Publication number: FI130440B
Application number: FI20196105A
Authority: FI
Inventors: Langh Hans; Reino Verosaari
Original assignee: Langh Tech Oy Ab
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2023-08-31
Also published as: FI20196105A1

Abstract

It is disclosed a method and apparatus for recovering carbon dioxide from exhaust gases produced by marine vessels, comprising the steps of: providing marine vessel exhaust gases containing carbon dioxide and having a content of sulphur oxides of at most 140 ppm; introducing the exhaust gases to a carbon dioxide absorption chamber (1); feeding a water solution to the absorption chamber; treating the exhaust gases with the water to provide a water effluent containing dissolved carbon dioxide; introducing the water effluent containing dissolved carbon dioxide to a liquid-gas separator (4) to provide carbon dioxide gas and a liquid having a reduced content of carbon dioxide; feeding the liquid having a reduced content of carbon dioxide to the absorption chamber; liquefying the carbon dioxide gas; recovering the liquefied carbon dioxide.

Description

METHOD FOR RECOVERING OF CARBON DIOXIDE FROM MARINE VESSEL EXHAUST

GASES

FIELD OF THE INVENTION

The present invention relates to a method of recovering carbon dioxide from exhaust gases produced by marine vessels. More particularly, the invention relates to a method of recovering carbon dioxide from diesel exhaust gases which have a low content of sulphur oxides.

BACKGROUND OF THE INVENTION

There is growing concern about climate change and carbon dioxide — emissions having an important effect on global warming. Carbon dioxide is pro- duced for example from the combustion of various engine fuels produced and emit- ted as exhaust gases into the atmosphere.

In addition to carbon dioxide, diesel fuels also contain problematic sul- phur oxide compounds. For example, ships using diesel fuels having a high sulphur content are equipped with scrubbers in which exhaust gases are washed with sea- water to reduce the emission of undesirable sulphur oxide compounds into the at- mosphere. In order to reduce emissions of sulphur oxides, limits on the maximum sulphur content of marine fuels are established. Depending on Emission Control

Area, the limit of sulphur varies. The general sulphur limit of 0.5% will apply on and after 1 January 2020 in sea areas. Some sea areas establish stricter levels, e.g. in SECA-area the upper limit for sulphur in the fuel is 0.1%. Globally, there is a con- tinuous tendency to reduce the limit for sulphur content of ships’ fuel oils.

Diesel fuel having a sulphur content of about 0.5% typically produces exhaust gases with a content of sulphur oxides of about 70 ppm. Diesel fuel having

N 25 a sulphur content of about 0.1% typically produces exhaust gases with a content of

N sulphur oxides of about 14 ppm. The diesel exhaust gases after reduction of sulphur

S oxide compounds still contain problematic carbon dioxide.

D US 2010/0224062 A1 discloses a method for removing sulphur dioxide = from diesel exhaust gases produced on a ship. In the method, the diesel exhaust * 30 gases are introduced to a scrubber in which the gases are washed with seawater.

S The acidic effluent seawater can be subjected to a degasifier to remove dissolved o carbon dioxide therefrom. Caustic is then added to the effluent seawater to neu- a tralize it to an acceptable pH level for discharge into the sea.

Awoyomi, A. et al., C02/S02 emission reduction in CO2 shipping infra-

structure. International Journal of Greenhouse Gas Control 88 (2019) 57-70, dis- cusses the reduction of CO2 and SO2 emissions in ships. In the process, flue gas is fed to a pre-treatment column for SO2 removal and then into two carbon dioxide absorber columns. D1 discloses that washing of flue gas is carried out by aqueous ammonia.

US 2016/0059180 A1 discloses recovery and storage of CO2 from en- gine exhaust gases. The method involves the steps of contacting exhaust gas stream with a CO2 capture agent, discharging a treated exhaust gas stream having a re- duced CO: content into the atmosphere, heating the CO? capture agent to release — the extracted CO2 and regenerate the capture agent, recovering, compressing and storing CO2.

EP 2823876 A1 discloses a system for chemically absorbing CO2 from combustion exhaust gas. COz is extracted from the exhaust gas with a CO2 absorb- ing liquid mainly composed of an aqueous alkanolamine solution. The CO2 absorb- ing liquid containing absorbed CO? is fed to a regeneration column for regenera- tion. The regenerated CO2 absorbing liquid is fed to the absorption column.

We have now found an efficient method for recovery of carbon dioxide from exhaust gases which are produced by marine vessels.

BRIEF DESCRIPTION OF THE INVENTION

In an aspect, the present invention provides a method of recovering car- bon dioxide from exhaust gases produced by marine vessels, comprising the steps of: - providing marine vessel exhaust gases containing carbon dioxide and having a content of sulphur oxides of at most 140 ppm, - introducing the exhaust gases to a carbon dioxide absorption chamber, - feeding a water solution to the absorption chamber, n - treating the exhaust gases with the water solution to provide a water

S effluent containing dissolved carbon dioxide,

O - introducing the water effluent containing dissolved carbon dioxide to = 30 = aliguid-gas separator to provide carbon dioxide gas and a liquid having a reduced

A content of carbon dioxide,

E - feeding the liguid having a reduced content of carbon dioxide to the 10 absorption chamber, © - liquefying the carbon dioxide gas, 5 35 - recovering the liquefied carbon dioxide.

N In another aspect, it is disclosed an apparatus for recovering carbon di- oxide from exhaust gases produced by marine vessels (not part of the invention),

comprising - a carbon dioxide absorption chamber (1) comprising an inlet (2) for introducing marine vessel exhaust gases having a content of sulphur oxides of at most 140 ppm to the absorption chamber (1), - an inlet (3) for feeding a water solution to the absorption chamber (1), - a liquid-gas separator (4) for receiving a water effluent from the ab- sorption chamber (1), containing dissolved carbon dioxide, - a conduit (6) for feeding a liquid discharged from the liquid-gas sepa- rator (4) and having a reduced content of carbon dioxide to the absorption cham- ber (1), - a compressor (11) for receiving carbon dioxide gas discharged from the liquid-gas separator (4), - condenser (12) to liquefy carbon dioxide gas discharged from the com- pressor (11), - a container (13) for recovering and storing the liquefied carbon diox- ide discharged from the condenser (12).

In a further aspect, itis disclosed a marine vessel (not part of the inven- tion) containing an apparatus disclosed herein.

An advantage of the method of the invention is that carbon dioxide gas is not emitted into the atmosphere but is efficiently recovered from the exhaust gases and optionally liquefied for storing and for later use in various applications.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows an embodiment of the apparatus disclosed herein.

Figure 2 shows another embodiment of the apparatus disclosed herein.

D 25 DETAILED DESCRIPTION OF THE INVENTION

N In an aspect, the invention provides a method for recovering carbon di-

S oxide from marine vessel exhaust gases containing a low content of sulphur oxides. > In the context of the present invention, the term "marine vessel” means any object = which is designed for floating on water, such as oceans, seas, lakes, rivers, etc. The so 30 marine vessel may include, without limitation, a ship, a ferry, a tanker, or an off- 2 shore drilling rig. o The exhaust gases can be produced from various sources employed on

N the marine vessels. Accordingly, the term “exhaust gases” encompasses any ex- haust gases produced by marine vessels, including without limitation exhaust gases from internal combustion engines, such as a diesel engine, or exhaust gases from boilers. In an embodiment, the exhaust gases used in the method of the inven- tion are derived from diesel exhaust gases, such as those produced on a ship.

In the following, the method of the invention and the apparatus (not part of the invention) are explained in more detail with reference to Figures 1 and 2,withoutlimiting the invention thereto. The optional embodiments of the method and the apparatus are illustrated and shown as dashed lines in Figure 2. The op- tional embodiments can be carried out in any combination with each other.

In the method of the invention, exhaust gases containing carbon dioxide and having a content of sulphur oxides of at most 140 ppm are used. In an embod- iment, the content of sulphur oxides is at most 100 ppm. In another embodiment, the content of sulphur oxides is at most 70 ppm. In a further embodiment, the con- tent of sulphur oxides is at most 14 ppm. In an embodiment, the exhaust gases used in the method are diesel exhaust gases.

Generally, exhaust gases may contain sulphur oxides in a higher amount — than 140 ppm. For example, ships may use diesel fuels which produce exhaust gases containing more than 140 ppm sulphur oxides. In that case, the exhaust gases are washed in a scrubber 14 to reduce the sulphur oxide content to a level of at most 140 ppm prior to subjecting the exhaust gases to the recovery of carbon di- oxide in accordance with the method of the invention. In an embodiment, the ex- haustgases used in the method are derived from the scrubber 14 in which exhaust gases, such as diesel exhaust gases, containing sulphur oxides, produced on a ship are washed with a water solution to reduce the content of sulphur oxides of the exhaust gases to a level of at most 140 ppm.

The exhaust gases are fed via inlet 2 to the carbon dioxide absorption chamber 1 in which carbon dioxide gas is absorbed by a water solution. In an em- n bodiment, the exhaust gases are introduced to the lower part of the absorption

N chamber. In another embodiment, the exhaust gases are introduced to the upper o part of the absorption chamber. = A water solution is introduced into the absorption chamber 1 via inlet 3

YT 30 and brought into contact with the exhaust gases. When the water solution is in con-

E tact with the exhaust gases, carbon dioxide dissolve into the water solution. A wa- 0 ter effluent containing dissolved carbon dioxide is produced. In an embodiment, = the water solution is added to the upper part of the absorption chamber. In another 2 embodiment, the water solution is added to the lower part of the absorption cham-

N 35 — ber.

In an embodiment, the water solution and exhaust gases are fed to the absorption chamber so that they flow in opposite directions in the absorption chamber. The water solution can be seawater at an ambient temperature or fresh water, or a mixture thereof. In an embodiment, the water solution is fresh water.

The treatment with the water solution in the absorption chamber is car- 5 ried outaboutatan atmospheric pressure. In an embodiment, the treatment is car- ried out at a pressure higher than an atmospheric pressure.

The water effluent is discharged from the carbon dioxide absorption chamber 1 and fed to a liquid-gas separator 4. In the separator, carbon dioxide gas is separated from the water effluent whereby a liquid having a reduced content of — carbon dioxide is produced. The liquid having a reduced content of carbon dioxide is fed to the carbon dioxide absorption chamber 1 via conduit 6.

Carbon dioxide gas is discharged from the liquid-gas separator 4 and liquefied. The carbon dioxide gas is fed to a compressor 11 to increase the pressure of the gas and then further to a condenser 12 to liquefy carbon dioxide gas. The liquefied carbon dioxide is recovered and stored in a container 13.

In an embodiment, the water effluent from the carbon dioxide absorp- tion chamber 1 is introduced to a heating device 7 and heated to a temperature of about 20°C to about 100°C prior to subjecting the water effluent to the liquid-gas separator 4. In an embodiment, the water effluent is heated to a temperature of about 70°C to about 90°C In another embodiment, the water effluent is heated to about 80°C. Heating of the water effluent enhances the separation of carbon oxide gas from the water effluent.

In an embodiment, the separation of carbon dioxide gas from the water effluent in the liquid-gas separator 4 is carried out at a temperature of about 20°C to about 100°C. In an embodiment, the separation is carried out at a temperature n of about 70°C to about 90°C. In another embodiment, the separation is carried out

N at about 80°C. o In an embodiment, the liquid having a reduced content of carbon diox- = ide is cooled in a cooling device 8 prior to feeding it to the carbon dioxide absorp-

YT 30 tion chamber 1 to enhance the dissolution of carbon dioxide from the exhaust gases

E into water. It is desirable to reduce the temperature of the liguid having a reduced 0 content of carbon dioxide to a level which is as low as possible, depending on the = temperature of seawater and the efficiency of the cooling device. In an embodi- 2 ment, the temperature of the liquid after cooling is at most 40°C. In another em-

N 35 bodiment, the temperature of the liquid is at most 20°C. In a further embodiment, the temperature of the liquid is about 15°C.

In an embodiment, an alkaline chemical, such as NaOH or KOH or a mix- ture thereof, is added via inlet 9a to the liquid fed to the absorption chamber 1 via conduit 6, having a reduced content of carbon dioxide, prior to feeding the liquid to the absorption chamber 1. In an embodiment, the alkaline chemical is added so as to provide a pH of at least 6 to the liquid. In an embodiment, the pH of the liquid fed to the absorption chamber is about 8. Any other alkaline chemical suitable for adjusting the pH to a level of at least 6 can be employed.

In an embodiment, an alkaline chemical, such as NaOH or KOH or a mix- ture thereof, is added via inlet 9b to a water solution fed to the absorption chamber 1 via conduit 3 prior to feeding the water solution to the absorption chamber 1. In an embodiment, the alkaline chemical is added so as to provide a pH of at least 6 to the water solution. In an embodiment, the pH of the water solution fed to the ab- sorption chamber is about 8. Any other alkaline chemical suitable for adjusting the pH to a level of at least 6 can be employed.

In an embodiment, a catalyst is added via inlet 10 to the liquid fed to the absorption chamber 1 via conduit 6, having a reduced content of carbon dioxide, prior to feeding the liquid to the absorption chamber 1 to enhance the dissolution of carbon dioxide gas into water. The catalyst may be methanolamine or ethanola- mine or a mixture thereof. Any other catalyst commonly used to enhance the dis- — solution of carbon dioxide gas into water can be used.

In another aspect, it is disclosed an apparatus for recovering carbon di- oxide from exhaust gases produced by marine vessels (not part of the invention), comprising - a carbon dioxide absorption chamber (1) comprising an inlet (2) for introducing marine vessel exhaust gases having a content of sulphur oxides of at n most 140 ppm to the absorption chamber (1),

N -aninlet (3) for feeding a water solution to the absorption chamber (1), o - a liquid-gas separator (4) for receiving a water effluent from the ab- = sorption chamber (1), containing dissolved carbon dioxide,

YT 30 - a conduit (6) for feeding a liquid discharged from the liguid-gas sepa-

E rator (4) and having a reduced content of carbon dioxide to the absorption cham- 0 ber (1), = - a compressor (11) for receiving carbon dioxide gas discharged from 2 the liquid-gas separator (4),

N 35 - condenser (12) to liquefy carbon dioxide gas discharged from the com- pressor (11),

- a container (13) for recovering and storing the liquefied carbon diox- ide discharged from the condenser (12).

In an embodiment, the apparatus further comprises a heating device 7 upstream of the liquid-gas separator 4 for receiving and heating the water effluent containing dissolved carbon dioxide discharged from the absorption chamber 1.

In an embodiment, the apparatus further comprises a scrubber 14 in which the exhaust gases containing sulphur oxides, produced on a ship, are washed with water to reduce the content of sulphur oxides of the exhaust gases to a level of at most 140 ppm prior to feeding the exhaust gases to the absorption chamber 1.

In an embodiment, the apparatus further comprises a cooling device 8 downstream of the liquid-gas separator 4 for receiving and cooling the liquid hav- ing a reduced content of carbon dioxide discharged from the liquid-gas separator 4.

In an embodiment, the apparatus further comprises an inlet 9a for feed- ing an alkaline chemical to the conduit 6.

In an embodiment, the apparatus further comprises an inlet 9b for feed- ing an alkaline chemical to the inlet 3.

In an embodiment, the apparatus further comprises an inlet 10 for feed- inga catalyst to the conduit 6.

In an embodiment, the apparatus further comprises a container 5 up- stream of the compressor 11 for receiving and storing carbon dioxide gas dis- charged from the liquid-gas separator 4.

In a further aspect, itis disclosed a marine vessel (not part of the inven- — tion) containing an apparatus disclosed herein. The marine vessel includes, but is n not limited to, a ship, a ferry, a tanker, or an offshore drillingrig. In an embodiment,

N the marine vessel also contains a source which provides exhaust gases, such as an o internal combustion engine, or a boiler.

S

> x a 3

O i

Claims

1. A method of recovering carbon dioxide from exhaust gases produced by marine vessels, comprising the steps of: - providing marine vessel exhaust gases containing carbon dioxide and having a content of sulphur oxides of at most 140 ppm, - introducing the exhaust gases to a carbon dioxide absorption chamber, - feeding a water solution to the absorption chamber, - treating the exhaust gases with the water solution to provide a water effluent containing dissolved carbon dioxide, - introducing the water effluent containing dissolved carbon dioxide to a liquid-gas separator to provide carbon dioxide gas and a liquid having a reduced content of carbon dioxide, - feeding the liquid having a reduced content of carbon dioxide to the — absorption chamber, - liquefying the carbon dioxide gas, -recovering the liquefied carbon dioxide.

2. The method of claim 1, wherein exhaust gases are diesel exhaust gases.

3. The method of claim 1 or 2, wherein the exhaust gases have a content of sulphur oxides of at most 100 ppm, specifically at most 70 ppm, more specifically at most 14 ppm.

4. The method of any one of the preceding claims, wherein the treat- ment with the water solution in the absorption chamber is carried out about at an atmospheric pressure or at a higher pressure.

n

5. The method of any one of the preceding claims, wherein the water N solution is selected from at least one of seawater and fresh water, specifically fresh o water.

=

6. The method of any one of the preceding claims, wherein an alkaline m 30 chemical, such as NaOH, KOH or a mixture thereof, is added to the liquid having a E reduced content of carbon dioxide prior to feeding it to the absorption chamber.

0

7. The method of any one of the preceding claims, wherein an alkaline = chemical, such as NaOH, KOH or a mixture thereof, is added to the water solution 2 prior to feeding it to the absorption chamber. N 35

8. The method of any one of the preceding claims, wherein a catalyst, such as methanolamine or ethanolamine, is added to the liguid having a reduced content of carbon dioxide prior to feeding it to the absorption chamber.

9. The method of any one of the preceding claims, wherein the water effluent is heated to a temperature ranging from about 20°C to about 100°C, spe- cifically from about 70°C to about 90°C, more specifically to a temperature of about 80%, prior to introducing it to the liquid-gas separator.

10. The method of any one of the preceding claims, wherein the separa- tion of carbon dioxide gas and a liquid having a reduced content of carbon dioxide in the liquid-gas separator is carried out at a temperature of about 20°C to about 100°C, specifically at about 70°C to about 90°C, more specifically at about 80°C.

11. The method of any one of the preceding claims, wherein the liquid having a reduced content of carbon dioxide from the liquid-gas separator is cooled to a temperature of at most 40°C, specifically to at most 20°C, more specifically to about 15°C, prior to feeding it to the absorption chamber. ™ Ql O N © S o I a a LO O © O O N