Ship flue gas scrubbing apparatus and method

Abstract

A ship flue gas scrubbing apparatus and scrubbing method are provided. The apparatus includes a housing, an upper scrubbing layer at the upper side inside the housing, and a liquid collecting pool in the lower side inside the housing, a flue gas leading-in port between the scrubbing layer and the liquid collecting pool, a scrubbing seawater inlet above the scrubbing layer, and a cooler located at a flue gas passage between the flue gas inlet outside the housing and the scrubbing layer. The method includes leading flue gas, cooling, injecting scrubbing seawater, scrubbing and other steps.

Claims

1. A ship flue gas desulfurization method, comprising the steps of: a. cooling high temperature flue gas discharged by a ship engine into cooled flue gas by contact of the high temperature flue gas and seawater in gaps of fillings of a cooling layer in a housing; and b. removing SO.sub.2 from the cooled flue gas by contact of the cooled flue gas and the seawater in gaps of fillings of a scrubbing layer in the housing to produce clean flue gas; wherein the seawater that cools the high temperature flue gas first passes through the scrubbing layer to absorb SO.sub.2.

2. The ship flue gas desulfurization method according to claim 1, wherein the scrubbing layer is provided above the cooling layer.

3. The ship flue gas desulfurization method according to claim 1, wherein the scrubbing layer is adjacent to the cooling layer.

4. The ship flue gas desulfurization method according to claim 1, wherein seawater is arranged to flow along a liquid flow path on the surface of the fillings of the scrubbing layer and the cooling layer, while the high temperature flue gas is arranged to flow along a gas flow path in gaps of the seawater on the surface of the fillings of the scrubbing layer and the cooling layer.

5. The ship flue gas desulfurization method according to claim 1, wherein a temperature of the high temperature flue gas is 200-490° C.

6. The ship flue gas desulfurization method according to claim 5, wherein a temperature of the cleaned flue gas discharged from the outlet is 20-49° C.

7. The ship flue gas desulfurization method according to claim 1, wherein the cooling and the removing are carried out in two different functional sections in separate steps.

8. The ship flue gas desulfurization method according to claim 1, wherein the seawater comprises natural seawater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing a ship flue gas scrubbing apparatus according to an embodiment of the invention. The flue gas leading-in port 3.2 inside the housing is the exit of a flue gas inlet pipe 3 which is fixed at the bottom of the housing 1 and extends to the inside of the housing 1, and is suitable for the situation that the flue gas goes upward vertically to enter the scrubber. The cooler 4 is a cooling flow equalization layer 4′ located between the flue gas leading-in port 3.2 inside the housing and the scrubbing layer 7.

(2) FIG. 2 is a schematic diagram showing a ship flue gas scrubbing apparatus according to another embodiment of the invention. The flue gas leading-in port 3.2 is located at the inner wall of the housing 1, and is the exit of a flue gas leading pipe 3 which is fixedly connected to the side wall of the housing 1. It is suitable for the situation that flue gas enters the scrubber horizontally. The cooler 4 is a cooling flow equalization layer 4′ located between the flue gas leading-in port 3.2 inside the housing and the scrubbing layer 7.

(3) FIG. 3 shows a block diagram of the ship flue gas scrubbing method according to the present invention.

(4) FIG. 4 is a schematic diagram of a prior art technical resolution of the U.S. Pat. No. 7,056,367, which includes an co-axial nested inlet conduit, a hot conduit, an outlet conduit, a counter-flow passing gas exhaust, and a tank containing scrubbing liquid, wherein ends of the heat and outlet conduits are operatively interconnected and immersed in the scrubbing liquid in the tank, and the heat conduit has a star-shaped cross section to increase the heat conduction area, so as to pre-heat the exhaust gases with more heat to increase the temperature of the exhaust gas beyond the dew point by at least 30° C.

(5) FIG. 5 is a schematic diagram of a conventional bubbling scrubber, and five bubbling units are shown in the apparatus as illustrated.

(6) Names of components or structures corresponding to the reference numbers in the drawings are as follows.

(7) In FIG. 1 and FIG. 2: 1—housing, 2—high temperature flue gas, 3—flue gas leading pipe, 3.1—flue gas inlet outside the housing, 3.2—flue gas leading-in port inside the housing, 4—cooler, 4′—cooling flow equalization layer, 5—low temperature flue gas, 6—filling supporting frame, 7—scrubbing layer, 8—water distributor, 9—mist eliminator, 10—exhaust gas outlet, 11—discharging clean flue gas, 12—scrubbing seawater inlet pipe, 13—scrubbing seawater, 14—liquid collecting cover, 15 liquid collecting pool, 16—seawater discharging pipe, 17—discharged seawater; D—the diameter of the scrubber, which is a side length when the scrubber is rectangular; L—the height of the scrubber.

(8) In FIG. 3, a—leading flue gas in, b—injecting scrubbing seawater, c—scrubbing, d—cooling, e—discharging the clean gas, and f—discharging the scrubbing seawater.

(9) In FIG. 4 (the technical resolution of the U.S. Pat. No. 7,056,367), 18—gas inlet conduit and gas inlet; 19—hot conduit; 20—exhaust gas leading pipe; 21—tank containing scrubbing liquid; 22—scrubbing liquid; 23—mixing vanes, 24—mist eliminator vanes, 25—mixing exhaust and scrubbing liquid in the tank, 26—scrubbing gas re-heat area, and 27—scrubbing liquid inlet and outlet.

(10) In FIG. 5 (conventional bubbling scrubber), 28—scrubbing liquid, 29—entering gas, 30—bubbling hood unit, 31—discharging gas, and 32—inlet and outlet of scrubbing liquid.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) Further description of the ship flue gas scrubbing apparatus and method are given below with reference to the drawings and embodiments.

(12) A. Embodiments for the Ship Flue Gas Scrubbing Apparatus.

(13) Embodiment 1:

(14) As illustrated in FIG. 1, the flue gas leading-in port 3.2 inside the housing is the exit of the flue gas inlet pipe 3 which is fixed at the bottom of the housing 1 and extends to the inside of the housing 1. In the embodiment, the flue gas leading pipe 3 is always kept above acidic seawater surface in the liquid collecting pool 15, that is to say, the flue gas does not enter the acid seawater. It is suitable for the situation where the flue gas is leaded in vertically. It includes a housing 1. A scrubbing layer 7 with fillings is fixed at the upper side inside the housing. A liquid collecting pool 15 with a seawater outlet 16 is provided at the lower side inside the housing. A flue gas leading pipe 3, which leads the exhaust gas to be scrubbed from the outside into the housing 1, is connected to the housing wall of the housing 1. One end of the flue gas leading pipe 3 is a flue gas inlet 3.1 outside the housing, the other end is the flue gas leading-in port 3.2 inside the housing. The gas leading-in port 3.2 inside the housing extends into the housing 1, and it is located between the scrubbing layer 7 and the liquid collecting pool 15. A cooler 4 used for cooling the high temperature flue gas 2 is provided in the flue gas passage between the flue gas inlet 3.1 outside the housing of the flue gas leading pipe 3 and the scrubbing layer 7. A scrubbing seawater inlet 12 is provided above the scrubbing layer 7. A purified flue gas outlet 10 is provided at the top of the housing 1.

(15) The cooler 4 is a cooling flow equalization layer 4′ and is located between the flue gas leading-in port 3.2 inside the housing and the scrubbing layer 7. The cooling flow equalization layer 4′ is made up of high temperature resistance components and is fixed on the inner wall of housing 1. Alternatively it can be fixed on the inner wall of housing 1 by means of fasteners.

(16) The cooler 4 is a tube cooler or sheet cooler installed on the flue gas leading pipe 3. In another embodiment, the cooler 4 is a tube cooler or sheet cooler installed in an internal cavity of the flue gas leading pipe 3. In still another embodiment, the cooler 4 is a water spray system connected to the flue gas leading pipe 3 or the housing 1 for spraying cooling water to the high temperature flue gas 2. The water spray system can be a set of spray heads.

(17) The gas leading-in port 3.2 inside the housing 1 is fixed at the bottom of the housing 1 and extends to the exit of the flue gas leading pipe 3 inside the housing 1. a Facing the exit is a liquid collecting cover 14 for preventing the scrubbing seawater from entering the flue gas leading pipe 3.

(18) The gas leading-in port 3.2 inside the housing 1 is a through hole in the side wall of the housing 1, or an exit of the flue gas leading pipe 3 fixedly connected to the side wall of the housing 1.

(19) The liquid collecting pool 15 is composed of the lower side wall of the housing 1, the bottom of the housing 1 and the pipe wall of the flue gas leading pipe 3, or a separation plate outside the flue gas leading pipe 3. The separation plate is able to prevent the pipe wall of the flue gas leading pipe 3 from corrosion.

(20) The high temperature resistant components that make up the cooling flow equalization layer 4′ are high temperature resistant inorganic materials. In this embodiment, ceramic material is used, and metal or carbon fiber materials may also be used. The high temperature resistance components of the cooling flow equalization layer 4′ are composed of high temperature resistant fillings and a filling supporting frame. The filling supporting frame is directly fixed, or be fixed through fasteners, on the inner wall of the housing 1.

(21) In other embodiments, the cooling flow equalization layer 4′ may be a high temperature resistant grid or a high temperature resistant perforated plate, or the combination of both, which can be directly fixed, or be fixed through fasteners, on the inner wall of the housing 1.

(22) The scrubbing layer 7 is composed of fillings and a filling supporting frame. The filling supporting frame is directly fixed, or be fixed through fasteners, on the inner wall of the housing 1. The fillings in the scrubbing layer 7 are of a polymer material select from polypropylene, polyethylene, or ABS. The cost of using non-high temperature resistant materials may be much lower than using high temperature resistant materials, so that the cost of the apparatus is reduced significantly.

(23) Above the scrubbing layer 7 there is a water distributor 8 which can outflow downwards the scrubbing seawater in a horizontal and even distribution pattern. The water distributor 8 is composed of aligned water pipes or aligned water channels, or a combination of both. A mist eliminator 9 for eliminating mist drops in the exhaust gas is installed above the water distributor 8.

(24) The scrubbing liquid finally discharged out of the scrubber would be discharged to the ocean if it meets the environmental emission requirements of the sea area that the ship passes or/and stays, and would be temporarily kept in the waste water cabin or be discharged after further treatment if it does not meet the relevant requirements.

(25) The ship implemented with this embodiment is equipped with a diesel fuel engine of 7150 KW power, 9700 hp, 127 rpm, using fuel oil with sulfur content 3%. The key parameters are as follows:

(26) TABLE-US-00001 diameter of the scrubber housing (Dmm) 2523 height of the scrubber housing L(mm) 8750 Inlet flue gas volume (Kg/h) 48281 Inlet flue gas temperature ° C. 200~490 Inlet SO.sub.2 volume (Kg/h) 70 Inlet flue gas and dust volume (g/h) 245 Inlet NOx volume (g/KWh) 18.56 Scrubbing seawater volume (Ton/h) 96 Outlet discharged SO.sub.2 volume (Kg/h) 0.68 Outlet discharged flue gas and dust volume (g/h) 49 Outlet flue gas temperature ° C. 20~49 Outlet discharged NO.sub.x volume (g/KW .Math. h) 14.8 International restrictions of discharged NO.sub.x volume ≦17.0 (g/KW .Math. h)

(27) Embodiment 2:

(28) FIG. 2 illustrates a ship flue gas scrubbing apparatus of another embodiment. It is different from Embodiment 1 in that the flue gas leading-in port 3.2 inside the housing 1 is at the inner wall of the housing 1, and it is an exit of the flue gas leading pipe 3 that is fixedly connected on the side wall of the housing 1, which is able to always keeps the flue gas leading pipe 3 above acidic seawater surface in the liquid collecting pool 15. That is to say, the flue gas does not enter the acid seawater. It is suitable for the situation where the flue gas is led in horizontally. The liquid collecting pool 15 is composed of the side wall and the bottom of the housing 1 under the horizontal cross-section where the lower edge of the gas leading-in port 3.2 inside the housing lies.

(29) Embodiment 3:

(30) A ship flue gas scrubbing apparatus of still another embodiment is illustrated. It is different from the previous embodiment in that the cooler 4 is a tube cooler or sheet cooler installed on the flue gas leading pipe 3 or in a cavity inside the pipe.

(31) Embodiment 4:

(32) The difference from the above-described embodiment is in that that the cooler 4 is a water spray system for spraying cooling water to the high temperature gas 2 which is installed on the flue gas leading pipe 3 or it may be connected to the housing 1. The water spray system is a set of spray heads.

(33) B. Ship Flue Gas Scrubbing Method According to Embodiments of the Present Invention

(34) Embodiment 5:

(35) As illustrated in FIG. 3 which is a flowchart block diagram, it is a ship flue gas scrubbing method using seawater to scrub pollutants, primarily SO.sub.2, in the ship flue gas exhaust. The method includes the following steps. a. leading in flue gas: flue gas discharged by an engine is led into a scrubber, and the leaded-in flue gas is caused to flow upwards in the scrubber; b. injecting scrubbing seawater: the scrubbing seawater is injected into the scrubber from a scrubbing seawater entrance located above a scrubbing layer of the scrubber, and the scrubbing seawater is caused to flow downwards in the scrubber; c. scrubbing: scrubbing in a counter-flow way is realized by flowing the scrubbing seawater, which is injected from above the scrubber, through a scrubbing layer with fillings to contact low temperature flue gas that goes upwards; d. cooling: high temperature flue gas is cooled by a cooler. The scrubbing seawater flows downward through the cooler to reduce the temperature of the high temperature flue gas, then the cooled flue gas goes upwards to enter the scrubbing layer; e. discharging clean flue gas: after being scrubbed, clean gas goes upwards and is discharged via a cleaned flue gas outlet; f. discharging the scrubbing seawater: after being scrubbed, the seawater falls into a liquid collecting pool and is discharged from a seawater discharging outlet.

(36) In the ship flue gas scrubbing method, in the scrubbing step, the method of sufficiently scrubbing the low temperature flue gas going upwards is that, in the scrubbing layer, the flue gas and the scrubbing seawater is caused to contact and mix sufficiently at a gas-liquid contact surface of the fillings, and the flue gas going upwards is caused to be sufficiently scrubbed to remove the SO.sub.2 therefrom. In the step of discharging clean flue gas, discharging the clean flue gas is that the clean flue gas is caused to pass through a mist eliminator to eliminate mist drops in the flue gas and then is discharged from the cleaned flue gas outlet. An operational pressure loss of the flue gas is less than 110 millimeters of water column.

(37) The protection range of this invention is not limited by the embodiments described above.