PRETREATMENT DESULFURIZATION METHOD FOR SHIP FUEL OIL USING PRETREATMENT DESULFURIZATION AGENT

Abstract

Proposed is a pretreatment desulfurization method for marine fuel oil. The method includes a step of preparing a pretreatment desulfurization agent including (a) at least one oxide selected from the group consisting of SiO2, Al2O3, Fe2O3, TiO2, MgO, MnO, CaO, Na2O, K2O, and P2O3, (b) at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb, and (c) at least one liquid composition selected from the group consisting of sodium tetraborate (Na2B4O7.10H2O), sodium hydroxide (NaOH), sodium silicate (Na2SiO3). and hydrogen peroxide (H2O2). The method also includes a step of feeding the pretreatment desulfurization agent to a fuel supply line through which marine fuel oil is supplied to a marine engine at a certain ratio so that a fluid mixture containing the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine, thereby adsorbing and removing sulfur oxides during combustion of the fluid mixture.

Claims

1. A marine fuel oil pretreatment desulfurization method using a pretreatment desulfurization agent, the method comprising: preparing a pretreatment desulfurization agent comprising (a) at least one oxide selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3, (b) at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb, and (c) at least one liquid composition selected from the group consisting of sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O), sodium hydroxide (NaOH), sodium silicate (Na.sub.2SiO.sub.3) and hydrogen peroxide (H.sub.2O.sub.2); feeding the pretreatment desulfurization agent, at a predetermined ratio, to a marine engine fuel supply line that transports marine fuel oil to a marine engine so that a fluid mixture containing the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine, thereby adsorbing and removing sulfur oxides during combustion of the fluid mixture.

2. The method according to claim 1, wherein the oxide comprises 15 to 90 parts by weight of SiO.sub.2, 15 to 100 parts by weight of Al.sub.2O.sub.3, 10 to 50 parts by weight of Fe.sub.2O.sub.3, 5 to 15 parts by weight of TiO.sub.2, 20 to 150 parts by weight of MgO, 10 to 20 parts by weight of MnO, 20 to 200 parts by weight of CaO, 15 to 45 parts by weight of Na.sub.2O, 20 to 50 parts by weight of K.sub.2O, and 5 to 20 parts by weight of P.sub.2O.sub.3, and the metal comprises 0.0035 to 0.009 parts by weight of Li, 0.005 to 0.01 parts by weight of Cr, 0.001 to 0.005 parts by weight of Co, 0.006 to 0.015 parts by weight of Ni, 0.018 to 0.03 parts by weight of Cu, 0.035 to 0.05 parts by weight of Zn, 0.04 to 0.08 parts by weight of Ga, 0.02 to 0.05 parts by weight of Sr, 0.002 to 0.01 parts by weight of Cd, and 0.003 to 0.005 parts by weight of Pb.

3. The method according to claim 1, wherein the oxide and metal have a particle size of 1 to 2 μm and a specific gravity of 2.5 to 3.0.

4. The method according to claim 1, wherein the sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O) is contained in an amount of 20 to 130 parts by weight, the sodium hydroxide (NaOH) is contained in an amount of 15 to 120 parts by weight, the sodium silicate (Na.sub.2SiO.sub.3) is contained in an amount of 50 to 250 parts by weight, and the hydrogen peroxide (H.sub.2O.sub.2) is contained in an amount of 10 to 50 parts by weight.

5. The method according to claim 1, wherein the pretreatment desulfurization agent is configured such that the oxide, the metal, and the liquid composition form a metal chelate compound.

6. The method according to claim 1, wherein the pretreatment desulfurization agent has a sulfur oxide (SO.sub.x) adsorption effect that is activated at temperatures in a range of 400° C. to 1200° C.

7. The method according to claim 1, wherein the pretreatment desulfurization agent is mixed in a ratio of 0.1 to 10 parts by weight with respect to 100 parts by weight of the marine fuel oil.

8. The method according to claim 1, wherein the pretreatment desulfurization agent is mixed in a ratio of 6 parts by weight with respect to 100 parts by weight of the marine fuel oil.

9. The method according to claim 1, the marine fuel oil and the pretreatment desulfurization agent are mixed and supplied to the marine engine through line mixing.

10. The method according to claim 1, wherein the marine fuel oil is heavy oil such as bunker-A oil, bunker-B oil, or bunker-C oil, or light oil such as MGO, MDO, or DDO.

Description

DESCRIPTION OF DRAWINGS

[0023] FIG. 1 is a view illustrating an exemplary construction of a pretreatment desulfurization system according to the present invention;

[0024] FIG. 2 is a partially enlarged view of a region A of FIG. 1;

[0025] FIG. 3 is a view illustrating the result of concentration analysis of sulfur oxide (SO.sub.2) for the entire session of Experimental Example 1; and

[0026] FIG. 4 is a view illustrating the result of concentration analysis of sulfur oxide (SO.sub.2) for the entire session of Experimental Example 2.

BEST MODE

[0027] In the following description, the specific structural or functional descriptions for exemplary embodiments according to the concept of the present disclosure are merely for illustrative purposes, and those skilled in the art will appreciate that various modifications and changes to the exemplary embodiments are possible, without departing from the scope and spirit of the present disclosure. Therefore, the present disclosure is intended to cover not only the exemplary embodiments but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the embodiments as defined by the appended claims. Hereinafter, embodiments of the present invention will be described in detail in conjunction with the accompanying drawings.

[0028] The present invention uses a desulfurization catalyst (hereinafter, referred to as “pretreatment desulfurization agent”) including: (a) at least one oxide selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3; (b) at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb; and (c) at least one liquid composition selected from the group consisting of sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O), sodium hydroxide (NaOH), sodium silicate (Na.sub.2SiO.sub.3), and hydrogen peroxide (H.sub.2O.sub.2).

[0029] The pretreatment desulfurization agent according to the present invention preferably includes at least one oxide selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3. Preferably, the pretreatment desulfurization agent includes all of the oxides selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3 as in one example described below.

[0030] When SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3 are all included, the basic formula is K.sub.0.8-0.9(Al,Fe,Mg).sub.2(Si,Al).sub.4O.sub.10(OH).sub.2 which is a mineral commonly called illite. The illite has a 2:1 structure in which one octahedral layer is bonded between two tetrahedral layers. The octahedral layer has a dioctahedral structure in which only 2 cation sites out of 3 cation sites in the bonding structure are filled with cations. Due to the lack of a cation, the illite is overall negatively charged (−). For this reason, sulfur oxides (SO.sub.x) can be adsorbed when the mixture of a combustible material and the desulfurization catalyst is burned.

[0031] As the oxides, the pretreatment desulfurization agent may include 15 to 90 parts by weight of SiO.sub.2, 15 to 100 parts by weight of Al.sub.2O.sub.3, 10 to 50 parts by weight of Fe.sub.2O.sub.3, 5 to 15 parts by weight of TiO.sub.2, 20 to 150 parts by weight of MgO, 10 to 20 parts by weight of MnO, and 20 to 200 parts by weight of CaO, 15 to 45 parts by weight of Na.sub.2O, 20 to 50 parts by weight of K.sub.2O, and 5 to 20 parts by weight of P.sub.2O.sub.3.

[0032] In addition, the oxides may be mixed and then pulverized into fine particles having a particle size of 1 to 2 μm by a pulverizer before being prepared as the desulfurization catalyst. The oxides may have a specific gravity of 2.5 to 3.0 and may be in the form of powder that is streak-colored or silvery white.

[0033] The pretreatment desulfurization agent according to the present invention may include one or more metals selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb. As in one embodiment, all of the metals including Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb are preferably included.

[0034] As the metals, the pretreatment desulfurization agent may include 0.0035 to 0.009 parts by weight of Li, 0.005 to 0.01 parts by weight of Cr, 0.001 to 0.005 parts by weight of Co, 0.006 to 0.015 parts by weight of Ni, 0.018 to 0.03 parts by weight of Cu, 0.035 to 0.05 parts by weight of Zn, 0.04 to 0.08 parts by weight of Ga, 0.02 to 0.05 parts by weight of Sr, 0.002 to 0.01 parts by weight of Cd, and 0.003 to 0.005 parts by weight of Pb.

[0035] In addition, the metals, like the oxides, may be mixed and then pulverized into fine particles having a particle size of 1 to 2 μm by a pulverizer, the metals may have a specific gravity of 2.5 to 3.0, and the metals may be in the form of powder that is streak-colored and silvery white.

[0036] The pretreatment desulfurization agent according to the present invention may include at least one liquid composition selected from the group consisting of sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O), sodium hydroxide (NaOH), sodium silicate (Na.sub.2SiO.sub.3), and hydrogen peroxide (H.sub.2O.sub.2). Preferably, as in one embodiment, all of the liquid compositions including sodium tetraborate, sodium hydroxide, sodium silicate, and hydrogen peroxide may be contained.

[0037] The pretreatment desulfurization agent according to the present invention forms a metal chelate compound through coordination with the metals because the oxides and the liquid compositions are mixed and reacted to serve as a chelating agent.

[0038] In addition, the liquid composition may be adsorbed on ash generated when a combustible material is combusted so that the liquid composition may react with sulfur oxides present in the ash, thereby removing the sulfur oxides. NaBO.sub.2 is derived from the sodium tetraborate (Na.sub.2B.sub.4O.sub.7) undergoes hydrogenation to produce NaBH.sub.4, and the produced NaBH.sub.4 reacts with oxygen and sulfur oxides to form sodium sulfate (Na.sub.2SO.sub.4). Thus, the sulfur oxides are removed. The reactions are represented by Reaction Formulas 1 and 2 below.

NaBH.sub.4+O.sub.3.fwdarw.Na.sub.2O.sub.2+H.sub.2O+B  [Reaction Formula 1]

1) Na.sub.2O.sub.2+SO.sub.3.fwdarw.Na.sub.2SO.sub.4+O

2) Na.sub.2O.sub.2+SO.sub.2.fwdarw.Na.sub.2SO.sub.4

3) Na.sub.2O.sub.2+SO.fwdarw.Na.sub.2SO.sub.3  [Reaction Formula 2]

[0039] In addition, as the liquid compositions, the sodium tetraborate, the sodium hydroxide, the sodium silicate, and the hydrogen peroxide may be included in amounts of 20 to 130 parts by weight, 15 to 120 parts by weight, 50 to 250 parts by weight, and 10 to 50 parts by weight, respectively in the pretreatment desulfurization agent.

[0040] When the pretreatment desulfurization agent according to the present invention is mixed with a combustible material and combusted together at a temperature in a range of 400° C. to 1200° C., the effect of adsorbing sulfur oxides can be activated. However, when the mixture is combusted in a temperature range of 600° C. to 900° C., high efficiency can be obtained.

[0041] Hereinafter, a method of preparing the pretreatment desulfurization agent according to the present invention will be described.

[0042] The pretreatment desulfurization agent according to the present invention is prepared through a method including: (a) preparing an oxide powder by mixing and finely pulverizing at least one oxide selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3; (b) preparing a metal powder by mixing and finely pulverizing at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb; and (c) mixing the oxide mixture prepared in (a) and the metal mixture prepared in (b) with at least one liquid composition selected from the group consisting of sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O), sodium hydroxide (NaOH), sodium silicate (Na.sub.2SiO.sub.3), and hydrogen peroxide (H.sub.2O.sub.2).

[0043] In step (a), the oxide powder including at least one oxide selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, TiO.sub.2, MgO, MnO, CaO, Na.sub.2O, K.sub.2O, and P.sub.2O.sub.3 is mixed and finely ground with a fine pulverizer.

[0044] In this step, the oxide powder includes 15 to 90 parts by weight of SiO.sub.2, 15 to 100 parts by weight of Al.sub.2O.sub.3, 10 to 50 parts by weight of Fe.sub.2O.sub.3, 5 to 15 parts by weight of TiO.sub.2, 20 to 150 parts by weight of MgO, 10 to 20 parts by weight of MnO, and 20 to 200 parts by weight of CaO, 15 to 45 parts by weight of Na.sub.2O, 20 to 50 parts by weight of K.sub.2O, and 5 to 20 parts by weight of P.sub.2O.sub.3.

[0045] In addition, the finely ground oxide powder may be ground repeatedly until the particle size of the powder falls within a range of 1 to 2 μm.

[0046] In step (b), the metal powder including at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd and Pb is mixed and ground with a fine pulverizer.

[0047] The metal powder may include 0.0035 to 0.009 parts by weight of Li, 0.005 to 0.01 parts by weight of Cr, 0.001 to 0.005 parts by weight of Co, 0.006 to 0.015 parts by weight of Ni, 0.018 to 0.03 parts by weight of Cu, 0.035 to 0.05 parts by weight of Zn, 0.04 to 0.08 parts by weight of Ga, 0.02 to 0.05 parts by weight of Sr, 0.002 to 0.01 parts by weight of Cd, and 0.003 to 0.005 parts by weight of Pb.

[0048] In addition, the finely ground metal powder may be ground repeatedly until the particle size of the powder falls within a range of 1 to 2 μm.

[0049] In step (c), at least one liquid composition selected from the group consisting of sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O), sodium hydroxide (NaOH), sodium silicate (Na.sub.2SiO.sub.3), and hydrogen peroxide (H.sub.2O.sub.2) is mixed with the finely ground oxide powder and the finely ground metal powder prepared in step (a) and step (b) to prepare a desulfurization catalyst.

[0050] In this step, the sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O) may be contained in an amount of 20 to 130 parts by weight, the sodium hydroxide (NaOH) may be contained in an amount of 15 to 120 parts by weight, the sodium silicate (Na.sub.2SiO.sub.3) may be contained in an amount of 50 to 250 parts by weight, and the hydrogen peroxide (H.sub.2O.sub.2) may be contained in an amount of 10 to 50 parts by weight.

[0051] In addition, in this step, when mixing and reacting the mixed and finely ground oxide and metal powders prepared in steps (a) and (b), the oxide powder and the liquid composition act as a chelating agent so that a metal chelate compound can be formed.

[0052] In addition, the pretreatment desulfurization agent formed in this step is stabilized by sedimentation for 24 to 72 hours, and the sedimented pretreatment desulfurization agent is separated and dried naturally to be used as a powder catalyst for desulfurization. The liquid composition remaining after the sedimented desulfurization catalyst is separated may be used as a liquid catalyst for desulfurization.

[0053] In addition, in the desulfurization method using the pretreatment desulfurization agent according to the present invention, the desulfurization function may be activated when it is mixed and combusted with a combustible material.

[0054] A conventional desulfurization method removes sulfur oxides (SO.sub.x) from flue gas generated during combustion of a combustible material. The conventional method requires a desulfurization facility for performing the desulfurization process and incurs manpower and cost for operating the desulfurization facility. However, since the desulfurization method of the present invention burns the pretreatment desulfurization agent along with the combustible material, the pretreatment desulfurization agent removes sulfur oxides through adsorption during the combustion, thereby reducing the content of sulfur oxides in flue gas. In this way, the method of the present invention exhibits a desulfurization effect.

[0055] In addition, the combustible material to which the pretreatment desulfurization agent according to the present invention can be applied may be a combustible material that generates heat through combustion. Examples of the combustible material include coal, petroleum, waste, and biogas.

[0056] In addition, as described above, the pretreatment desulfurization agent is separated into a powder catalyst for desulfurization and a liquid catalyst for desulfurization. Each of the powder catalyst and the liquid catalyst is used alone or in combination with the other, depending on the contents of C, H, N, and S of the combustible material. Therefore, the pretreatment desulfurization agent of the present invention can exhibit an excellent desulfurization effect in a simple and easy way of use.

[0057] Hereinafter, the configuration of a pretreatment desulfurization system according to one embodiment of the present invention, which is to be applied to a marine engine, will be described in detail with reference to FIG. 1.

[0058] The pretreatment desulfurization system according to the present invention is connected to a fuel supply line 30 of a marine engine 70 to supply the pretreatment desulfurization agent (liquid catalyst for desulfurization) in a certain mixing ratio with respect to fuel.

[0059] Usually, as the fuel of the marine engine 70, marine fuel oil, for example, heavy oil such as bunker-A oil, bunker-B oil, or bunker-C oil, or light oil such as MGO, MDO, or DDO is used. Among them, bunker C oil is a high sulfur oil and generates a large amount of sulfur oxides during combustion thereof. Therefore, the use of bunker-C oil is regulated due to air pollution.

[0060] In FIG. 1, reference numerals 10, 20, 30, 40, 50, and 60 denote a fuel tank, a fuel supply pump, a fuel supply line, a fuel filter, an injection pump, and an injection nozzle, respectively. A detailed description of the components will be omitted.

[0061] To this end, the pretreatment desulfurization system according to the present invention is equipped with a desulfurization agent tank 110 having a predetermined volume for storing the pretreatment desulfurization agent, and one end of the desulfurization agent tank 110 is connected to a metering pump 130 for quantitatively supplying the pretreatment desulfurization agent.

[0062] In addition, a flow meter 120 for checking the input flow rate of the pretreatment desulfurization agent, a check valve 140 for adjusting the input flow rate, and a pressure gauge 150 are installed on the fuel supply line 30 between the metering pump 130 and the marine engine 70. Therefore, it is possible to continuously check the fuel supply amount to the marine engine 70 and regulate the supply of the pretreatment desulfurization agent so that the pretreatment desulfurization agent is supplied in a predetermined ratio with respect to the fuel supply amount.

[0063] The pretreatment desulfurization agent is preferably supplied and mixed in an amount of 0.1% to 10% by weight relative to 100% by weight of the marine fuel oil.

[0064] Referring to FIG. 2, the pretreatment desulfurization agent is connected to a line mixer 160 provided on the fuel supply line 30 for supplying the marine fuel oil, and the pretreatment desulfurization agent injected from one side and the marine fuel oil are sufficiently mixed in the line mixer 160 (this process is called line mixing). The sufficiently mixed fluid mixture of the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine.

[0065] Thereafter, the fluid mixture is combusted in the marine engine. Therefore, sulfur oxides generated during a combustion process are adsorbed and removed by the pretreatment desulfurization agent before being discharged to the outside.

[0066] Through this process, even when high-sulfur marine fuel oil such as bunker-C oil is used as fuel, since sulfur oxides are almost perfectly removed during the combustion, it is possible to solve the air pollution problem caused by sulfur oxides.

[0067] Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples.

[0068] Examples and Test Examples presented herein are only for illustrative purposes and are not intended to limit the scope of the present invention.

<Example> Preparation of Pretreatment Desulfurization Agent

[0069] As oxides, SiO.sub.2 150 kg, Al.sub.2O.sub.3 150 kg, Fe.sub.2O.sub.3 100 kg, TiO.sub.2 50 kg, MgO 200 kg, MnO 100 kg, CaO 200 kg, Na.sub.2O 150 kg, K.sub.2O 200 kg, and P.sub.2O.sub.3 50 kg were mixed and finely ground to form fine oxide powder.

[0070] As metals, Li 35 g, Cr 50 g, Co 10 g, Ni 60 g, Cu 180 g, Zn 350 g, Ga 400 g, Sr 200 g, Cd 20 g, and Pb 30 g were mixed and finely ground to form fine metal powder.

[0071] The fine oxide powder and the fine metal powder are repeatedly ground to have a particle size of 1 to 2 μm.

[0072] 3000 kg of water was put into a reactor, the water was maintained at a temperature of 50° C. to 60° C., and 50 kg of sodium tetraborate (Na.sub.2B.sub.4O.sub.7.10H.sub.2O) were added thereto. After stirring for 30 minutes, 100 kg of sodium hydroxide (NaOH) was added and stirred. Next, after 10 minutes, the fine oxide powder was added in units of 100 kg at intervals of 5 minutes and stirred for 2 hours or more. While stirring, the temperature was raised to 60° C. to 80° C., and 100 kg of sodium silicate (Na.sub.2SiO.sub.3) was added. After stirring for 30 minutes, the fine metal powder was added in units of 20 g at intervals of 3 minutes and stirred. After stirring for 1 hour, 30 kg of hydrogen peroxide (H.sub.2O.sub.2) was added, stirred for another 30 minutes, and then naturally cooled for 1 hour.

[0073] After cooling and stabilizing for 48 hours, the liquid composition and the sedimented powder composition are separated from each other.

[0074] The sedimented powder composition was dried naturally and named as a powder catalyst for desulfurization (GTS-P).

[0075] In addition, the liquid composition remaining after the sedimented powder composition was removed was moved to a separate container and named as a liquid catalyst for desulfurization (GTS-W).

<Experimental Example 1> Test for Checking Reduction in Sulfur Oxide in Marine Engine Exhaust Gas

[0076] (1) Test Condition

[0077] In order to evaluate the desulfurization efficiency of the pretreatment desulfurization agent (liquid catalyst for desulfurization) prepared as described above, 3.5% and 6.0% by weight of the pretreatment desulfurization agent was supplied to a fuel supply line connected to a marine engine so as to be mixed with 100% by weight of fuel, and the mixture was burned. Next, a sulfur oxide reduction performance test was conducted to analyze and compare the concentration of sulfur oxides in exhaust gas.

[0078] The specifications of the marine engine used for the test are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Specifications of engine for test Maker Yanmar Model 4LOD Horse power (Hp) 200 Number of Cylinders 4 in-line Combustion system Direct injection Aspiration Natural aspirated Dimensions (L × W × H, mm) 500 × 1550 × 1400 Cooling system Direct water cooling Marine gear Mechanical Fuel consumption rate 100 mL/min [0079] Fuel used: bunker-C oil [0080] Operation condition: no-load operation [0081] Supply amount and method of pretreatment desulfurization agent: 3.5% and 6.0% by weight of the pretreatment desulfurization agent was mixed and supplied to the fuel supply line with a metering pump with respect to the fuel flow rate. [0082] Marine engine exhaust gas analysis system: German VarioPlus Ind. MRU Emission Monitoring System [0083] Marine engine exhaust gas analysis method: exhaust gas was sampled from an exhaust pipe connected to an engine and was analyzed with an analysis system (standard oxygen concentration of 17%) [0084] Since the oxygen concentration in the exhaust gas was maintained at 17% to 18% in the engine no-load operation condition, the reference oxygen concentration was set to 17% to prevent an excessive difference between the measured concentration and the corrected concentration that is based on the reference oxygen concentration.

[0085] (2) Test Method and Procedures

[0086] 1) Main engine operation state and normal state

[0087] 2) Preheat exhaust gas analysis system and perform zero setting

[0088] 3) Perform measurement in a condition in which no pretreatment desulfurization agent was injected (30 minutes)

[0089] 4) Perform measurement in a condition in which 6.0% by weight of pretreatment desulfurization agent was injected (1 hour)

[0090] 5) Repeat step 3) and step 4) one more time

[0091] 6) Perform measurement in a condition in which no pretreatment desulfurization agent was injected (30 minutes)

[0092] 7) Perform measurement in a condition in which 3.5% by weight of pretreatment desulfurization agent was injected (1 hour)

[0093] 8) Perform measurement in a condition in which no pretreatment desulfurization agent was injected (30 minutes)

[0094] 9) Perform measurement in a condition in which 6.0% by weight of pretreatment desulfurization agent was injected (1 hour)

[0095] 10) Save data and stop analysis

TABLE-US-00002 TABLE 2 Test Condition Time Test condition 11:21-11:54 Fuel oil 11:54-13:20 Pretreatment desulfurization agent 6.0% by weight 13:20-14:03 Fuel oil 14:03-15:06 Pretreatment desulfurization agent 6.0% by weight 15:06-15:46 Fuel oil 15:46-16:46 Pretreatment desulfurization agent 3.5% by weight 16:46-17:23 Fuel oil 17:23-18:25 Pretreatment desulfurization agent 6.0% by weight

[0096] (3) Result of Analysis of Sulfur Oxide (SO.sub.2) Concentration (in Terms of 17% Reference Oxygen Concentration)

[0097] FIG. 3 shows the analysis results of sulfur oxide (SO.sub.2) concentration for the entire session of Experimental Example 1 performed according to the test conditions, methods, and procedures described above, and Table 3 summarizes data of the values of SO.sub.2 concentration in each measurement session of FIG. 3. (in terms of 17% of reference oxygen concentration)

TABLE-US-00003 TABLE 3 SO.sub.2 concentration for measurement session (in terms of 17% of reference oxygen concentration) SO.sub.2 Measurement concentration time Test condition (ppm) Note 11:35-12:00 Fuel oil 102.00 Average value 12:23-13:00 Pretreatment 0.01 Average desulfurization agent value 6.0% by weight 14:08 Fuel oil 100.0 Peak value 14:26-15:15 Pretreatment 0.00 Average desulfurization agent value 6.0% by weight 15:51 Fuel oil 95.2 Peak value 16:22-16:52 Pretreatment 29.19 Average desulfurization agent value 3.5% by weight 17:28 Fuel oil 94.5 Peak value 17:50-18:25 Pretreatment 0.00 Average desulfurization agent value 6.0% by weight

[0098] Referring to FIG. 3 and Table 3, after 6.0% by weight and 3.5% by weight of the pretreatment desulfurization agent relative to 100% by weight of the fuel oil were sequentially injected into the fuel supply line, the concentration of SO.sub.2 was measured for each case. That is, the test was performed with four measurement sessions.

[0099] In a first measurement session, when only fuel oil was burned (measurement time: 11:35-12:00), the concentration of SO.sub.2 in the exhaust gas was 102.00 ppm, but when 6.0% by weight of the pretreatment desulfurization agent was added (measurement time: 12:23-13:00), the concentration of SO.sub.2 rapidly dropped to 0.01 ppm.

[0100] In a second measurement session, when only fuel oil was burned (measurement time: 14:08)), the concentration of SO.sub.2 in the exhaust gas was 100.00 ppm, but when 6.0% by weight of the pretreatment desulfurization agent was added relative to 100% by weight of fuel oil (measurement time: 14:26-15:15), the concentration of SO.sub.2 rapidly dropped to 0.00 ppm.

[0101] In a third measurement session, when only fuel oil was burned (measurement time 15:51), the concentration of SO.sub.2 in the exhaust gas was 95.2 ppm, but when 3.5% by weight of the pretreatment desulfurization agent was added relative to 100% by weight of fuel oil (measurement time 16:22-16:52), the concentration of SO.sub.2 rapidly dropped to 29.19 ppm.

[0102] In a fourth measurement session, when only fuel oil was burned (measurement time: 17:28), the concentration of SO.sub.2 in the exhaust gas was 94.5 ppm, but when 6.0% by weight of the pretreatment desulfurization agent was added relative to 100% by weight of fuel oil (measurement time: 17:50-18:25), the concentration of SO.sub.2 rapidly dropped to 0.00 ppm.

[0103] The measurement results showed that the effect of reducing the SO.sub.2 emissions was improved when the mixing ratio of the pretreatment desulfurization agent was increased from 3.5% by weight to 6.0% by weight.

<Experimental Example 2> Test for Checking Reduction in Sulfur Oxide in Marine Engine Exhaust Gas

[0104] (1) Test Condition

[0105] The same as in Test Example 1

[0106] (2) Test Method and Procedures

[0107] The same as in Test Example 1

TABLE-US-00004 TABLE 4 Test Condition Time Test condition 09:06-09:44 Fuel oil 09:44-10:54 Pretreatment desulfurization agent 3.5% by weight 10:54-11:10 Fuel oil 11:10-11:37 Engine stop 11:37-13:02 Fuel oil 12:02-13:08 Pretreatment desulfurization agent 6.0% by weight

[0108] (3) Result of Analysis of Sulfur Oxide (SO.sub.2) Concentration (in Terms of 17% Reference Oxygen Concentration)

[0109] FIG. 4 shows the analysis results of sulfur oxide (SO.sub.2) concentration for the entire session of Experimental Example 2 performed according to the test conditions, methods, and procedures described above, and Table 5 summarizes data of the values of SO.sub.2 concentration in each measurement session of FIG. 4. (In terms of a reference oxygen concentration of 17%)

TABLE-US-00005 TABLE 5 SO.sub.2 concentration for each measurement session (in terms of the reference oxygen concentration of 17%) Concentration Measurement of SO.sub.2 time Test condition (ppm) Note 09:12-09:40 Fuel oil 96.43 Average value 10:18-10:51 Pretreatment 29.54 Average value desulfurization agent 3.5% by weight 11:55-12:44 Fuel oil 98.93 Average value 12:57-13:06 Pretreatment 0.00 Average value desulfurization agent 6.0% by weight

[0110] Referring to FIG. 4 and Table 5, after 6.0% by weight and 3.5% by weight of the pretreatment desulfurization agent relative to 100% by weight of the fuel oil were injected into the fuel supply line, the concentration of SO.sub.2 was measured for each case. That is, the test was performed with two measurement sessions.

[0111] In a first measurement session, when only fuel oil was burned (measurement time: 09:12-09:40), the concentration of SO.sub.2 in the exhaust gas was 96.43 ppm, but when 3.5% by weight of the pretreatment desulfurization agent was input relative to 100% by weight of fuel oil (measurement time: 10:18-10:51), the concentration of SO.sub.2 rapidly dropped to 29.54 ppm.

[0112] In a second measurement session, when only fuel oil was burned (measurement time: 11:55-12:44), the concentration of SO.sub.2 in the exhaust gas was 98.93 ppm, but when 6.0% by weight of the pretreatment desulfurization agent was input relative to 100% by weight of fuel oil (measurement time: 12:57-13:06), the concentration of SO.sub.2 rapidly dropped to 0.00 ppm.

[0113] The measurement results showed that the effect of reducing the SO.sub.2 emissions was improved when the mixing ratio of the pretreatment desulfurization agent was increased from 3.5% by weight to 6.0% by weight.

[0114] As can be seen from the results of Experimental Examples 1 and 2, when fuel and the pretreatment desulfurization agent were burned together, the SO.sub.2 concentration in the exhaust gas was reduced by at least 69% and by 100% at a maximum compared to the case where only fuel is burned. In addition, when the pretreatment desulfurization agent was increased from 3.5% by weight to 6.0% by weight, the reduction in the SO.sub.2 emissions was increased.

INDUSTRIAL APPLICABILITY

[0115] The present invention can be widely used for pretreatment desulfurization for marine fuel oil.