CN205700083U - A kind of boat diesel engine tail gas desulfurization denitration combined apparatus - Google Patents

Abstract

The purpose of this utility model is to provide a marine diesel engine tail gas desulfurization and denitrification combined treatment device, including a diesel engine, a turbocharger, a waste heat boiler, and an exhaust scrubber. The diesel engine is connected to an exhaust manifold and a scavenging box respectively, and the exhaust manifold passes The turbine inlet pipeline is connected to the turbine inlet, the turbine outlet is connected to the inlet of the waste heat boiler through the turbine outlet pipeline, the turbine outlet pipeline is connected to the turbine inlet pipeline through the waste gas bypass passage, and the compressor outlet is connected to the scavenging box through the compressor outlet pipeline , the outlet pipeline of the compressor is connected with the exhaust manifold through the compressed air bypass passage, the outlet of the waste heat boiler is connected with the outlet pipeline of the waste heat boiler, and the outlet pipeline of the waste heat boiler is connected with the exhaust gas scrubbing and desulfurization passage and the discharge pipeline through a three-way way. The waste gas scrubbing and desulfurization channel is connected to the inlet of the tail gas scrubber, and the outlet of the tail gas scrubber is connected to the discharge pipeline and then connected to the atmosphere. The utility model can meet the NOX and SOX discharge requirements of marine diesel engines in IMO regulations.

Description

A combined treatment device for marine diesel engine tail gas desulfurization and denitrification

technical field

The utility model relates to a diesel engine tail gas treatment device, in particular to a marine diesel engine tail gas treatment device.

Background technique

With the rapid development of the shipping industry, the emission of ship exhaust gas is increasing day by day, and the harm to the environment is becoming more and more serious. According to the data from the Monitoring Center of the Ministry of Environmental Protection, in 2013, ships berthing at Chinese ports emitted a total of 588,000 tons of sulfur dioxide, accounting for about 8.4% of the country's total emissions; port ships emitted 278,000 tons of nitrogen oxides, accounting for about 8.4% of the country's total emissions. 11.3% of total emissions. The International Maritime Organization (IMO) has formulated a series of anti-pollution conventions, which strictly limit the emission of harmful components in ship exhaust. From January 1, 2016, the emission requirements of ships in the emission control area shall meet the Tier III emission standard.

Marine diesel engine emission reduction technologies mainly include the use of low-sulfur fuel oil and exhaust gas washing technology. Relatively speaking, it is more convenient to use low-sulfur fuel oil, and the changes to the ship are small, and it can meet the IMO requirements for the sulfur content of ship fuel oil. The use of low-sulfur fuel has problems such as low viscosity, poor lubricity, and easy wear, which will cause certain damage to the engine, and low-sulfur fuel will produce a large amount of CO2 during the refining process, which will intensify the global warming effect.

The removal of NOX mainly uses Selective Catalytic Reduction (SCR), using NH3 to reduce NO to N2. Due to the low temperature of the gas after desulfurization, the SCR reaction requires a higher temperature, and the gas needs to be heated twice to denitrify.

As an effective method approved by IMO to remove ship exhaust gas desulfurization (FGD), exhaust gas scrubbing technology cleans the exhaust gas produced by burning low-quality high-sulfur heavy oil, removes SOX, and meets IMO's requirements for fuel oil sulfur content. Wet FGD has high desulfurization efficiency, but it is difficult to denitrify at the same time, because more than 90% of NOX in the actual exhaust gas of marine diesel engines is NO, and NO is hardly absorbed by water or lye except for the formation of complexes .

At present, the research and treatment of ship exhaust NOX and SOX are carried out separately, that is, two sets of different equipment are used to treat NOX and SOX respectively. This exhaust gas series treatment method has huge equipment volume and high back pressure, which has a great impact on the normal operation of the engine, and the equipment investment and operation costs are very high.

Contents of the invention

The purpose of the utility model is to provide a ship diesel engine tail gas desulfurization and denitrification combined treatment device that can meet the requirements of IMO regulations on NOX and SOX emissions of ship diesel engines.

The purpose of this utility model is achieved in that:

The utility model discloses a marine diesel engine tail gas desulfurization and denitrification combined treatment device, which is characterized in that it includes a diesel engine, a turbocharger, a waste heat boiler, and a tail gas scrubber, the turbocharger includes a turbine and a compressor, and the diesel engine is connected to an exhaust manifold respectively. and the scavenging box, the exhaust manifold is connected to the turbine inlet through the turbine inlet pipe, the turbine outlet is connected to the inlet of the waste heat boiler through the turbine outlet pipe, the turbine outlet pipe is connected to the turbine inlet pipe through the waste gas bypass passage, and the waste gas bypass passage The first one-way stop valve is installed on the road. The compressor outlet is connected to the scavenging box through the compressor outlet pipeline. The bypass passage is connected, and the second one-way stop valve is installed on the compressed air bypass passage. The outlet of the waste heat boiler is connected to the outlet pipeline of the waste heat boiler. The scrubbing and desulfurization pathway is connected to the inlet of the exhaust gas scrubber, the outlet of the exhaust gas scrubber is connected to the discharge pipeline and then connected to the atmosphere, the exhaust gas scrubbing and desulfurization pathway is equipped with a catalytic oxidation device, the catalytic oxidation device is connected to the ozone generator, and the exhaust gas scrubber is connected to the water treatment unit.

The utility model has the advantages of:

1. A marine diesel engine exhaust desulfurization and denitrification combined treatment system adopted in the utility model meets the relevant IMO emission standards for ships.

2. The utility model adopts the ozone catalytic oxidation method to convert NO which is difficult to be absorbed by lye into NO2 which is easily absorbed by lye, which greatly improves the washing and denitrification efficiency of lye on NOX.

3. Since a set of equipment is used to simultaneously remove NOX and SOX in the exhaust gas of the engine, the volume and weight of the device of the utility model are significantly smaller than the sum of the volume and weight of the devices for desulfurization and denitrification respectively. The equipment is compact and can save ships and effectively The space, investment cost and operation cost are low, and the impact on the engine is small.

4. The exhaust gas bypass technology is adopted to ensure the safety of the operation of the exhaust gas scrubbing, desulfurization and denitrification device.

5. While desulfurizing and denitrifying the tail gas of marine diesel engines, it can also reduce the emission of particulate matter.

Description of drawings

Fig. 1 is the structural representation of the utility model.

detailed description

The utility model is described in more detail below in conjunction with accompanying drawing example:

With reference to Fig. 1, the marine diesel engine tail gas desulfurization and denitrification joint treatment system of the present utility model is suitable for a marine power plant. The air intercooler 6 and the water droplet catcher 7 on the top, the turbine 10 connected to the exhaust manifold, and the compressor 4 arranged on the intake passage; the intake passage communicates with the outlet of the compressor 4 and the scavenging box 8, Contains air intercooler 6 and water droplet collector 7; turbine waste gas bypass passage containing one-way stop valve 11 is directly connected to turbine inlet 10 and waste heat boiler 12 inlet; compressed air bypass passage including one-way stop valve 5 is directly connected to The outlet of the compressor 4 and the inlet of the turbine 10; the exhaust gas scrubbing and desulfurization passage and the waste gas bypass passage controlled by the three-way valve 13.

When the ship is running in the emission control area, all the exhaust gas from the diesel engine is passed into the turbine through the exhaust manifold 3, expands in the turbine 10 to perform work, and drives the compressor 4 to work. The compressor 4 compresses fresh air, and the compressed air passes through the air intercooler 6 Cool down, enter the water droplet catcher 7, remove the water droplets contained in it, enter the scavenging air box 8, and then pass through the intake pipe 9, enter the diesel engine 1, and participate in combustion; The shut-off valve 11 is closed, and when the engine is working under high load, the exhaust gas of the diesel engine is excessive, and the one-way shut-off valve 11 in the turbine waste gas bypass passage is opened to bypass excess exhaust gas and improve engine efficiency.

Depending on whether the exhaust gas washing device 16 is put into operation, the marine diesel engine system is divided into two operating modes, a non-washing mode and a washing mode.

Non-scrubbing mode: When the ship is sailing in a non-emission control area and a non-port area, the exhaust gas passes through the waste heat boiler 12 to recover energy, passes through the three-way valve 13, and is directly discharged into the ambient atmosphere through the waste gas bypass passage.

Scrubbing mode: when the ship is navigating in the sulfur emission control area or port area, the exhaust gas passes through the waste heat boiler 12 to recover energy, passes through the three-way valve 13, flows into the catalytic oxidation device 15 through the exhaust gas scrubbing and desulfurization passage, and the ozone generated by the ozone generator 14 Oxidation reaction occurs; the oxidized waste gas enters the waste gas washing device 16, and is washed with lye to remove NOX, SOX and particles. The processing unit 17 processes.

When the marine waste gas washing device is repaired or fails, the waste gas passes through the three-way valve 13 and is directly discharged into the atmosphere through the waste gas bypass passage.

The device of the utility model comprises an air intake system connected between an exhaust manifold connected with the exhaust pipe of the diesel engine and a scavenging box connected with the intake pipe of the diesel engine, and the air intake system includes The turbine, the compressor driven by the turbine, and the air intercooler connected between the compressor outlet and the scavenging box. The air intake system also includes a compressed air bypass passage including a first one-way stop valve connected between the compressor outlet and the exhaust manifold, and a waste gas bypass pipeline is arranged between the turbine inlet and outlet, and the waste gas bypass A fourth one-way stop valve is arranged on the pipeline, the waste gas bypass pipeline is connected to the waste heat boiler, and the waste heat boiler is connected to the waste gas scrubbing device through a three-way valve or directly connected to the atmosphere. An air droplet catcher is installed between the air intercooler and the scavenging air box. Before the tail gas scrubber, there is an ozone generator and a catalytic oxidizer. The scrubber adopts a one-stage or multi-stage spray tower structure, or a packed tower structure. The NOX and SOX emission control device of the marine diesel engine of the utility model comprises a diesel engine system, an ozone oxidation device and an exhaust gas washing device. In the diesel engine system, a water drop catcher is added after the air intercooler. In the diesel engine system, a turbine waste gas bypass passage is added to communicate with the turbine inlet and outlet. A compressed air bypass passage is added to connect the compressor outlet and the turbine inlet.

In the diesel engine system, the non-recirculating exhaust gas passes through the waste heat boiler, then passes through the three-way valve, or goes to the exhaust gas cleaning device for washing or is directly discharged into the atmosphere.

In the combined emission reduction device, the exhaust gas prewashing device, scrubber and exhaust gas scrubbing device adopt a one-stage or multi-stage spray tower structure, or adopt a packed tower structure.

The main features of the combined desulfurization and denitrification treatment method for marine diesel engine tail gas of the utility model are:

When the ship is navigating in the nitrogen oxide emission control area, the exhaust gas of the diesel engine is completely fed into the turbine through the exhaust manifold, and works to drive the compressor to work, compress fresh air, and the compressed air passes through the air intercooler to cool down, enters the water droplet collector, and removes The water droplets contained in it enter the scavenging air box, and then enter the diesel engine through the intake pipe to participate in combustion; the one-way stop valve in the compressed air bypass passage is closed, and when the engine is working under high load, open the one-way stop valve in the turbine waste gas bypass passage , Bypass excess exhaust gas.

After the exhaust gas recovers energy through the waste heat boiler, it flows into the catalytic oxidation device from the exhaust gas washing and desulfurization passage through the three-way valve, and undergoes a catalytic oxidation reaction with the ozone generated by the ozone generator; the oxidized exhaust gas enters the exhaust gas washing device, and is washed with lye to remove it. The NOX, SOX and particles are discharged into the ambient atmosphere after the demister at the top of the washing device removes the water droplets, and the washed wastewater enters the water treatment unit for treatment.

The main harmful gas components in marine diesel engine tail gas are NO and SO2, so the utility model mainly treats SO2 and NO in flue gas. Sodium-alkali washing has a high removal efficiency for SOX, but the removal effect for NO is not ideal; through the ozone catalytic oxidation method, NO is converted into NO2, which is easily absorbed by alkali solution, and combined desulfurization and denitrification are realized at the same time.

The chemical reaction process of the present utility model is as follows:

1. Tail gas desulfurization process

O ₃ +SO ₂ →SO ₃ +O ₂

2NaOH+SO ₃ →Na ₂ SO ₄ +H ₂ O

SO ₃ +H ₂ O→H ₂ SO ₄

2NaOH _{+ H2SO4 → Na2SO4 +} 2H2O

2. Tail gas denitrification process

O ₃ +NO→NO ₂ +O ₂

O ₃ +NO ₂ →NO ₃ +O ₂

NO ₃ +NO ₂ →2N ₂ O ₅

N ₂ O ₅ +H ₂ O→2HNO ₃

2NaOH+2NO ₂ →NaNO ₃ +NaNO ₂ +H ₂ O

NaOH+HNO ₃ →NaNO ₃ +H ₂ O

The utility model discloses a combined treatment device for desulfurization and denitrification of marine diesel engine tail gas. The main components of the flue gas emitted by marine diesel engines when using heavy oil are SOX and NOX. In the emission control area, after the exhaust gas passes through the waste heat boiler to recover energy, it flows into the catalytic oxidation device through the exhaust gas scrubbing and desulfurization passage through the three-way valve, and undergoes a catalytic oxidation reaction with the ozone generated by the ozone generator; the oxidized exhaust gas enters the exhaust gas scrubbing device and The NOX, SOX and particles are removed by liquid washing, and the water droplets are removed by the demister at the top of the washing device, and then discharged into the ambient atmosphere, and the washed wastewater enters the water treatment unit for treatment. The utility model adopts a desulfurization and denitrification combined treatment system, which saves equipment investment and reduces the occupied area. While improving the energy utilization rate of marine diesel engines, it can efficiently remove SOX and NOX in the exhaust gas, meeting the standards of IMO emission regulations.

Claims (1)

1. A marine diesel engine tail gas desulfurization and denitrification combined treatment device is characterized in that: it includes a diesel engine, a turbocharger, a waste heat boiler, and an exhaust gas scrubber, the turbocharger includes a turbine and a compressor, and the diesel engine is connected to the exhaust manifold and The scavenging box, the exhaust manifold is connected to the turbine inlet through the turbine inlet pipeline, the turbine outlet is connected to the inlet of the waste heat boiler through the turbine outlet pipeline, the turbine outlet pipeline is connected to the turbine inlet pipeline through the waste gas bypass passage, and the exhaust gas bypass passage The first one-way stop valve is installed, the compressor outlet is connected to the scavenging box through the compressor outlet pipeline, an air cooler and a water droplet collector are installed on the compressor outlet pipeline, and the compressor outlet pipeline and the exhaust manifold pass through the compressed air side A second one-way stop valve is installed on the compressed air bypass passage. The outlet of the waste heat boiler is connected to the outlet pipeline of the waste heat boiler. The desulfurization channel is connected to the inlet of the exhaust gas scrubber, the outlet of the exhaust gas scrubber is connected to the discharge pipeline and then connected to the atmosphere, the exhaust gas scrubbing and desulfurization channel is equipped with a catalytic oxidation device, the catalytic oxidation device is connected to the ozone generator, and the exhaust gas scrubber is connected to the water treatment unit.