DE102014016369A1 - A method of operating an internal combustion engine with an internal combustion engine and an exhaust aftertreatment system downstream of the internal combustion engine for the purification of the exhaust gas - Google Patents

Abstract

Method for operating an internal combustion engine (1), in particular a marine diesel engine operated with heavy oil, wherein the internal combustion engine (1) has an internal combustion engine (2) for combustion of fuel and an exhaust aftertreatment system (3) connected downstream of the internal combustion engine (2) for cleaning during combustion of the engine Has fuel resulting exhaust (5). The internal combustion engine (2) is operated with vanadiumhaltigem fuel. Exhaust gas (5), which is formed during combustion of the vanadium-containing fuel, is passed over a granular particle separator (4) in the form of a moving bed or fluidized bed reactor in which catalytically active compound for denitrification of the exhaust gas (5) during combustion of the vanadium-containing fuel resulting V2O5 is deposited on the granules (6) of the particle separator (4). Upstream of the particle separator (4), ammonia or an ammonia precursor substance is introduced into the exhaust gas (5) as a reducing agent (7) for denitrification of the exhaust gas (5).

Description

The invention relates to a method for operating an internal combustion engine according to the preamble of claim 1.

From the prior art known internal combustion engines, such as marine diesel engines, have an internal combustion engine in which a fuel is burned, as well as a downstream of the engine exhaust aftertreatment system for purifying the resulting in the combustion of the fuel in the engine exhaust gas. Marine diesel engines are preferably operated with heavy oil.

From practice it is known to subject the exhaust of a denitrification and preferably a desulfurization in an exhaust aftertreatment system of an internal combustion engine. For denitrification of the exhaust gas so-called SCR catalysts are used according to the prior art. For the desulfurization of exhaust gas absorptive processes are primarily known from the prior art, which use fire-absorbent (CaO) or hydrated lime (Ca (OH) ₂ ) or calcium carbonate (CaCO ₃ ) as absorption medium. During desulfurization, dust is formed from calcium sulfate (CaSO ₄ ), which is typically removed from the exhaust gas via a filter device.

Although processes for denitrification and desulfurization of exhaust gas are already known from the prior art, there is a need to improve the denitrification and possibly desulfurization of exhaust gas, in particular for marine diesel engines operated with heavy oil.

On this basis, the present invention is a novel method for operating an internal combustion engine to create.

This object is achieved by a method for operating an internal combustion engine according to claim 1. According to the invention, the internal combustion engine is operated with vanadium-containing fuel. The exhaust gas produced during the combustion of the vanadium-containing fuel is passed through a granular particle separator in the form of a moving bed or fluidized bed reactor in which V ₂ O ₅ produced as a catalytically active compound for denitrification of the exhaust gas during the combustion of the vanadium-containing fuel is deposited on the granules of the particle separator becomes. Upstream of the particle separator, ammonia or an ammonia precursor substance is introduced into the exhaust gas as a reducing agent for denitrification of the exhaust gas.

According to the invention, it is proposed to operate the internal combustion engine with vanadium-containing fuel. During the combustion of the vanadium-containing fuel in the internal combustion engine, V ₂ O _{5 is formed} , which serves as a catalytically active compound for the denitrification of the exhaust gas. This V ₂ O ₅ is deposited on the granules of the Partikelabscheiders, so that in the particle V ₂ O ₅ for the denitrification of the exhaust gas is present. In addition, ammonia or an ammonia precursor substance is introduced into the exhaust gas upstream of the particle separator as a reducing agent for denitrification. As a result, a particularly effective denitrification of exhaust gas of an internal combustion engine is possible in combination.

According to an advantageous development of the internal combustion engine is operated with fuel, the vanadium in a concentration of more than 20 mg / kg, preferably more than 40 mg / kg, more preferably more than 80 mg / kg. Then, when the fuel has the above-defined vanadium concentrations, sufficient V ₂ O ₅ for the denitrification of the exhaust gas is present in the region of the particle separator.

According to an advantageous development, the internal combustion engine is operated with lubricating oil comprising vanadium in a concentration of more than 2 mg / kg, preferably more than 5 mg / kg, more preferably more than 10 mg / kg. This is advantageous in large engines, which also burns lubricating oil in order to provide sufficient V ₂ O ₅ for denitrification in the region of the particle separator.

According to a further advantageous development, the exhaust gas is passed upstream of the Partikelabscheiders and / or downstream of the Partikelabscheiders via an SCR catalyst. The denitrification can be improved in that the exhaust gas is additionally guided via an SCR catalyst, upstream of the Partikelabscheiders and / or downstream of the Partikelabscheiders.

According to a further advantageous development calcium-containing and / or sodium-containing granules are used to provide an additional desulfurization of the exhaust gas as granules comprising CaO and / or Ca (OH) ₂ and / or CaCO ₃ and / or NaCO ₃ and / or NaHCO ₃ . This can be carried out in addition to denitrification and desulfurization of the exhaust gas in the particle separator.

The concentration of calcium and / or sodium-containing granules increases towards the outlet.

Preferably, the separator is designed in several stages and the concentration and / or amount of calcium and / or sodium-containing granules is lower at the gas inlet of the separator than at the gas inlet.

Preferably, the exhaust gas is passed upstream of the introduction of ammonia or the ammonia precursor substance into the exhaust gas via an oxidation catalyst for the oxidation of SO ₂ in SO ₃ . In this way, the desulfurization of the exhaust gas can be improved because SO ₃ reacts faster than SO ₂ with the above calcium-containing and / or sodium-containing granules.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:

1 1 is a block diagram of an internal combustion engine comprising an internal combustion engine and an exhaust aftertreatment system;

2 1 is a block diagram of an internal combustion engine comprising an internal combustion engine and an exhaust aftertreatment system;

3 1 is a block diagram of an internal combustion engine comprising an internal combustion engine and an exhaust aftertreatment system; and

4 1 is a block diagram of an internal combustion engine including an internal combustion engine and an exhaust aftertreatment system.

The present invention relates to a method for operating an internal combustion engine, by means of which exhaust gas can be effectively entstickt and optionally desulfurized.

1 shows a block diagram of an internal combustion engine 1 that is an internal combustion engine 2 and an internal combustion engine 2 Downstream exhaust aftertreatment system 3 includes. In the internal combustion engine 2 it is preferably an internal combustion engine of a ship operated with heavy oil, in which heavy fuel oil is burnt as fuel.

The exhaust aftertreatment system 3 includes at least one particle separator 4 over which the internal combustion engine 2 leaving exhaust 5 for denitrification and optionally desulfurization is performed, wherein it is in the particle 4 to a granular particle separator 4 in the form of a moving bed reactor or fluidized bed reactor. Preferably, this moving bed or fluidized bed reactor is designed as a cross-flow reactor, in which a flow direction of the internal combustion engine 2 leaving exhaust gas 5 perpendicular to a flow direction of the granules 6 through the particle separator 4 runs.

For the purposes of the present invention, the internal combustion engine 2 operated with vanadiumhaltigem fuel. In the combustion of the vanadium-containing fuel resulting exhaust gas contains V ₂ O ₅ , which serves as a catalytically active compound for denitrification of the exhaust gas, wherein the resulting during the combustion of the vanadium-containing fuel V ₂ O ₅ on the granules 6 of the particle separator 4 in the particle separator 4 is deposited. Upstream of the particle separator 4 is used as a reducing agent 7 For denitrification of the exhaust gas ammonia or an ammonia precursor substance introduced into the exhaust gas.

Accordingly, in order to provide exhaust gas during operation of an internal combustion engine which has been subjected to effective denitrification, the internal combustion engine is used according to the invention 2 operated with vanadiumhaltigem fuel. V ₂ O ₅ produced during the combustion of the vanadium-containing fuel is applied to the granules of the particle separator 4 separated and in the denitrification of the exhaust gas in the particle separator 4 used as a catalyst. As a reducing agent 7 ammonia serving for the denitrification or a corresponding ammonia precursor substance becomes upstream of the particle separator 4 in the exhaust 5 brought in.

Preferably, the internal combustion engine 2 operated with a fuel comprising vanadium in a concentration of more than 20 mg / kg, preferably in a concentration of more than 40 mg / kg, more preferably in a concentration of more than 80 mg / kg.

Especially in large engines, such as in marine diesel engines, in which in the internal combustion engine 2 Also lubricating oil is burned, is additionally provided that the internal combustion engine 2 is operated with vanadium-containing lubricating oil, wherein the lubricating oil has a vanadium concentration of more than 2 mg / kg, preferably more than 5 mg / kg, particularly preferably more than 10 mg / kg.

The particle separator 4 is preferably operated such that a residence time of the exhaust gas 5 in the particle separator more than 0.2 sec, preferably more than 0.8 sec, more preferably more than 1.5 sec.

This is a traveling or flow rate of the granules 6 in the particle separator 4 preferably set such that in Particle separator V ₂ O _{5 is present} in a concentration of more than 20 mg / kg, preferably more than 40 mg / kg, more preferably more than 80 mg / kg.

The in the particle separator 4 used granules 6 preferably has a particle size of 1 mm to 8 mm.

According to 2 can the denitrification of the internal combustion engine 2 leaving exhaust gas 5 be improved by the exhaust 5 upstream of the particle separator 4 via an SCR catalyst 8th to be led. The reducing agent 7 for the denitrification of the exhaust gas, which is ammonia or an ammonia precursor, is according to 2 upstream of the SCR catalyst 8th into the ammonia 5 brought in.

In deviation to 2 it is alternatively or additionally possible, also downstream of the Partikelabscheiders 4 To provide an SCR catalyst to further improve the denitrification of the exhaust gas.

According to a further variant of the invention is provided, the exhaust gas 5 additionally in the particle separator 4 to undergo a desulfurization. This is done according to 3 that the internal combustion engine 2 leaving exhaust 5 via an oxidation catalyst 9 in which SO _{2 is} oxidized in SO ₃ . Additionally comes in 3 in the area of the particle separator 4 calcium-containing granules and / or sodium-containing granules 6 used to which the sulfur oxides of the exhaust gas to desulfurization of the same react with the granules.

The granules used here are preferably CaO and / or Ca (OH) ₂ and / or CaCO ₃ and / or NaCO ₃ and / or NaHCO ₃ . It is important that SO ₃ faster with the calcium-containing granules and / or sodium-containing granules of Partikelabscheiders 4 reacts as SO ₂ , so through the use of the oxidation catalyst 9 the desulfurization in the particle separator 4 can be improved. The reaction of the calcium-containing and / or sodium-containing powder with SO ₂ and SO ₃ is carried out by way of example for Ca (OH) ₂ , CaCO ₃ and NaHCO ₃ according to the following reaction equations,
namely for Ca (OH) ₂ according to the following reaction equations Ca (OH) ₂ + SO ₂ ↔ CaSO ₃ + H ₂ O Ca (OH) ₂ + SO ₂ + 1 / 2O ₂ ↔ CaSO ₄ + H ₂ O Ca (OH) ₂ + CO ₂ ↔ CaCO ₃ + H ₂ O Ca (OH) ₂ + SO ₃ ↔ CaCO ₄ + H ₂ O for CaCO ₃ according to the following reaction equations CaCO ₃ + SO ₂ ↔ CaSO ₃ + CO ₂ CaCO ₃ + SO ₂ + 1 / 2O ₂ ↔ CaSO ₄ + CO ₂ CaCO ₃ + SO ₃ ↔ CaSO ₄ + CO ₂ for NaHCO ₃ according to the following reaction equations 2NaHCO ₃ → Na ₂ CO ₃ + CO ₂ + H ₂ O Na ₂ CO ₃ + SO ₂ + 1 / 2O ₂ → Na ₂ SO ₄ Na ₂ CO ₃ + SO ₃ → Na ₂ SO ₄

This produces powdered calcium sulfate CaSO ₄ and sodium sulfate Na ₂ SO ₄ , which together with the granules 6 the trained as a moving bed reactor or fluidized bed reactor particle separator 4 from the particle separator 4 can be discharged.

The concentration of calcium and / or sodium-containing granules increases towards the outlet. The separator is designed in several stages and the concentration and / or amount of calcium and / or sodium-containing granules at the gas inlet of the separator is lower than at the gas inlet is.

4 illustrates a variant of the invention, in which the variants of 2 and 3 used in combination with each other, in which the exhaust so upstream of the Partikelabscheiders 4 both via an oxidation catalyst 9 for the oxidation of SO ₂ and SO ₃ as well as via an SCR catalyst 8th to be led.

In all embodiments of the 1 to 4 is upstream of the particle separator 4 as a reducing agent 7 for the nitrogen oxides NOx of the exhaust gas 5 Ammonia or an ammonia precursor substance into the exhaust gas 5 brought in. In this case, either ammonia NH ₃ directly into the exhaust gas or as ammonia precursor substance urea in the exhaust gas 5 be injected.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

2

internal combustion engine

3

aftertreatment system

4

particle

5

exhaust

6

granules

7

reducing agent

8th

SCR catalyst

9

oxidation catalyst

Claims (11)

Method for operating an internal combustion engine ( 1 ), in particular a heavy fuel oil-driven marine diesel engine, wherein the internal combustion engine ( 1 ) an internal combustion engine ( 2 ) for combustion of fuel and a combustion engine ( 2 ) downstream exhaust aftertreatment system ( 3 ) for purifying exhaust gas produced during the combustion of the fuel ( 5 ), characterized in that the internal combustion engine ( 2 ) is operated with vanadium-containing fuel; the exhaust gas produced during combustion of the vanadium-containing fuel ( 5 ) over a granule-containing particle separator ( 4 ) is conducted in the form of a moving bed or fluidized bed reactor, in which as catalytically active compound for denitrification of the exhaust gas ( 5 ) V ₂ O ₅ resulting from the combustion of the vanadium-containing fuel on the granules ( 6 ) of the particle separator ( 4 ) is deposited; upstream of the particle separator ( 4 ) as a reducing agent ( 7 ) for the denitrification of the exhaust gas ( 5 ) Ammonia or an ammonia precursor substance into the exhaust gas ( 5 ) is introduced. Method according to Claim 1, characterized in that the internal combustion engine ( 2 ) is operated with fuel comprising vanadium in a concentration of more than 20 mg / kg, preferably more than 40 mg / kg, more preferably more than 80 mg / kg. Method according to Claim 1 or 2, characterized in that the internal combustion engine ( 2 ) is operated with lubricating oil containing vanadium in a concentration of more than 2 mg / kg, preferably more than 5 mg / kg, more preferably more than 10 mg / kg. Method according to one of claims 1 to 3, characterized in that the particle separator ( 4 ) is operated such that a residence time of the exhaust gas ( 5 ) in the particle separator ( 4 ) is more than 0.2 s, preferably more than 0.8 s, more preferably more than 1.5 s. Method according to one of claims 1 to 4, characterized in that a traveling or flow rate of the granules ( 6 ) in the particle separator ( 4 ) is set such that in the particle separator ( 4 ) V ₂ O ₅ in a concentration of more than 20 mg / kg, preferably more than 40 mg / kg, more preferably more than 80 mg / kg. Method according to one of claims 1 to 5, characterized in that the exhaust gas ( 5 ) upstream of the particle separator ( 4 ) and / or downstream of the particle separator ( 4 ) via an SCR catalyst ( 8th ) to be led. Method according to one of claims 1 to 6, characterized in that the grain size of the granules ( 6 ) in the particle separator between 1 mm and 8 mm. Method according to one of claims 1 to 7, characterized in that to provide an additional desulfurization of the exhaust gas ( 5 ) as granules ( 6 ) calcium-containing and / or sodium-containing granules ( 6 ), which comprises CaO and / or Ca (OH) ₂ and / or CaCO ₃ and / or NaCO ₃ and / or NaHCO ₃ . A method according to claim 8, characterized in that the concentration of calcium and / or sodium-containing granules increases towards the outlet. A method according to claim 8, characterized in that the separator is designed in several stages and the concentration and / or amount of calcium and / or sodium-containing granules at the gas inlet of the separator is lower than at the gas inlet. Method according to one of claims 1 to 10, characterized in that the exhaust gas ( 5 ) upstream of the introduction of ammonia or the ammonia precursor substance into the exhaust gas via an oxidation catalyst ( 9 ) is led to the oxidation of SO ₂ in SO ₃ .

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