CN104819040A - A marine diesel engine exhaust gas treatment and utilization device and its working method - Google Patents

Abstract

The invention discloses a marine diesel engine waste gas treatment and utilization device and a working method thereof, wherein the device comprises a waste gas treatment system, a waste gas waste heat power generation system and an electrolysis system, the waste gas waste heat power generation system comprises an organic Rankine cycle unit, a generator and a storage battery, and the electrolysis system comprises an electrolysis unit, an alkali liquor cabinet, a mixing cabinet and an alkali liquor supply pump; the waste gas treatment system comprises a flue gas heat exchanger, a washing tower, a seawater spraying device and an aeration tank. The invention is based on organic Rankine cycle, fully utilizes the waste heat of the exhaust gas of the marine diesel engine to generate electricity, and directly uses the generated electric energy for the desulfurization treatment of the exhaust gas of the marine diesel engine. The electric energy used by the electrolysis unit is from the electric energy generated by the waste heat of the ship exhaust gas, no additional electric energy is needed to be input, the ship exhaust gas treatment cost is greatly saved, and the purpose of treating the exhaust gas by the waste heat of the exhaust gas is really achieved. The invention adopts the waste heat of the diesel engine waste gas to generate electricity to treat the diesel engine waste gas, so that the on-line treatment can be carried out.

Description

A marine diesel engine exhaust gas treatment and utilization device and its working method

technical field

The invention relates to a waste heat utilization technology of ship waste gas, in particular to a ship diesel engine waste gas treatment and utilization device and its working method.

Background technique

According to IMO (International Maritime Organization) data, ships emit 6.34 million tons of SO ₂ every year, accounting for about 4% of the world's emissions. The air pollution caused by ships has reached a level that cannot be ignored. In some places where ports and straits are densely populated, ship exhaust gas has become the main source of local air pollution. In September 1997, the International Maritime Organization passed Annex VI of the _MARRPOL Convention (International Convention for the Prevention of Pollution from Ships). In 2011, the 58th meeting of MPEC (Marine Environment and Protection Committee) passed the amendment to Annex VI of the MARPOL Convention, which put forward further requirements for the emission of air pollutants from ships. The amendment requires that starting from January 1, 2012, the sulfur content of global heavy fuel oil will be reduced from the current 4.5% to 3.5%; and a feasibility assessment will be made before 2018, and if the assessment is passed, by January 1, 2020 Japan will require the sulfur content of global marine heavy oil to be reduced to 0.5%. For the sulfur emission control area, starting from July 1, 2010, the sulfur content of marine heavy oil in this area shall not exceed 1.0%; from January 1, 2015, it shall not exceed 0.1%.

At present, the main methods for ships to reduce SO ₂ emissions are: 1. Use of low-sulfur fuel oil; 2. Alternative fuels; 3. Post-treatment of flue gas. Due to the advantages of simple process, high desulfurization efficiency and low operation cost, flue gas post-treatment will be the main direction of future research. As far as the ship's own characteristics are concerned, seawater desulfurization is considered to be a very suitable and promising method among all ship flue gas post-treatment methods, but this method needs to consume a large amount of seawater as an absorbent, so it is necessary to configure high-power Seawater pumps are used to maintain the normal operation of the system; in addition, the seawater after desulfurization is acidic, which not only corrodes the equipment, but also needs to be treated with alkaline substances before it can be discharged. These problems can be avoided by using electrolysis of seawater to treat tail gas, but electrolysis of seawater requires a large amount of electrical energy, which puts enormous pressure on the ship's power grid.

At present, energy saving and emission reduction have become the main theme advocated by ship design and manufacturing. As far as the current situation of ships is concerned, a large amount of waste heat contained in the exhaust gas of ship diesel engines has not been utilized. After the fuel is burned in the cylinder of the diesel engine, it cannot be completely converted into shaft power. Generally, only 30%-55% of the heat is converted into effective work, and the remaining 45%-70% of the heat is lost in various forms. For large ships, the energy contained in the exhaust gas of marine diesel engines accounts for about 25.5% of the total heat of fuel, of which about 12% can be used, accounting for about 1/4 of the effective power of diesel engines. Under the premise of energy conservation and emission reduction to achieve sustainable development, how to improve energy utilization and reduce ship exhaust emissions will become a major challenge for the shipping industry. At present, the exhaust heat utilization equipment of marine diesel engines is limited to exhaust turbochargers and exhaust gas boilers. The exhaust gas turbocharger converts the energy in the exhaust gas into the pressure of the intake air to improve the power and efficiency of the diesel engine; the exhaust gas boiler uses the energy of the exhaust gas to generate saturated steam of about 0.5MPa to meet the crew's daily water use and the heating and insulation of the oil tank wait. However, with the development of ships in the direction of large-scale, high-speed, and automation, less and less steam is used for the crew's daily life, which makes the utilization of exhaust heat from marine diesel engines increasingly insufficient and unreasonable. In addition, the energy in the jacket water of marine diesel engine (the temperature is about 80-90°C) is not effectively utilized, which causes a lot of energy waste. How to make more effective use of the exhaust heat of marine diesel engines is of great value both from the perspective of environmental protection and from the perspective of economy, which is also a major problem currently facing.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention designs a marine diesel engine exhaust gas treatment and utilization device and its working method which can reduce the energy consumption of exhaust gas treatment and make more use of waste heat of exhaust gas.

In order to achieve the above object, the technical scheme of the present invention is as follows:

A marine diesel engine exhaust gas treatment and utilization device, including an exhaust gas treatment system, an exhaust gas waste heat power generation system, and an electrolysis system. The waste gas waste heat power generation system includes an organic Rankine cycle unit, a generator and a storage battery. The organic Rankine cycle unit Connected with the diesel engine supercharger through the flue gas pipeline; the organic Rankine cycle unit includes a circulating pump, an evaporator, an expander, a condenser and a jacket water heat exchanger; the high temperature of the jacket water heat exchanger The side is connected to the exhaust gas of the diesel engine, and the low-temperature side is connected to the jacket water of the diesel engine. The circulation pump is connected with the evaporator, expander, and condenser in sequence to form a cycle; the expander and the generator are connected by Flange connection; the generator is connected to the electrolysis unit through the battery through the cable; the electrolysis system includes the electrolysis unit, the lye cabinet, the mixing cabinet and the lye supply pump; the cathode outlet of the electrolysis unit and the lye cabinet Connected through pipelines; the outlet of the lye tank and the seawater mixing tank are connected through pipelines; the mixing tank is connected with the washing tower through the pipeline through the lye supply pump; The seawater desalination system, liquid filling pump, buffer cabinet, seawater supply pump and electrolyzer are connected in sequence through pipelines; the seawater supply pump is connected through valves and buffer cabinets; The heater is evenly arranged at the bottom of the buffer cabinet; the exhaust gas treatment system includes a flue gas heat exchanger, a scrubber, a seawater spray device and an aeration tank; between the flue gas heat exchanger and the scrubber, the flue gas heat exchanger It is connected with the seawater spraying device through the flue gas pipeline, and the seawater spraying device and the washing tower are connected with the aeration tank through the pipeline.

A working method of a marine diesel engine exhaust gas treatment and utilization device, comprising the following steps:

A. After the marine diesel engine exhaust gas is discharged from the turbocharger, it first enters the organic Rankine cycle unit through the bypass baffle. In the organic Rankine cycle unit, the waste heat of the diesel engine exhaust gas is used to generate electricity, and the generated electric energy is stored in the battery. In order to achieve the purpose of storing electric energy;

B. The organic Rankine cycle unit first uses the heat in the exhaust gas of the marine diesel engine to heat the jacket water of the diesel engine to 90-150°C, and the heated jacket water exchanges heat with the organic working medium in the evaporator. After the heat exchange, the jacket water of the diesel engine is circulated back to the main engine; the heated organic medium enters the expander to expand and do work, and the organic medium after the work is cooled in the condenser, and the cooled organic working medium is sent back to the evaporation by the circulating pump again Heat exchange in the device, so repeated cycle;

C. The battery supplies power to the electrolysis unit through wires, and at the same time, the battery also supplies power to the lye supply pump, and the remaining electric energy in the battery supplies power to other electrical equipment on the ship.

D. The electrolysis unit electrolyzes the high-concentration seawater produced by the ship’s seawater desalination system. The chlorine gas generated by the anode of the electrolysis unit is passed into the ship’s ballast tank to treat the ship’s ballast water. The lye produced by the cathode of the electrolysis unit is transported and stored in the lye cabinet, the generated hydrogen is sent to the kitchen for fuel;

E. After the exhaust gas of the marine diesel engine is discharged through the organic Rankine cycle to generate electricity, the first cooling of the exhaust gas of the diesel engine is realized, and secondly, heat exchange is performed with the exhaust gas after desulfurization treatment in the flue gas heat exchanger to realize the second cooling of the exhaust gas of the diesel engine. Cooling; before entering the spray tower for desulfurization treatment, it will be sprayed with seawater for the third time to cool down;

F. The lye supply pump pumps the mixture of lye and seawater produced by the electrolysis unit to the spray tower, and at the same time sends the cooled diesel engine exhaust gas to the spray tower for spray treatment;

G. After being treated by the spray tower, the exhaust gas is heated up and discharged through the flue gas heat exchanger.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention is based on the organic Rankine cycle, fully utilizes the exhaust heat of marine diesel engines to generate electricity, and directly uses the generated electric energy for desulfurization treatment of marine diesel engine exhaust gases. The electric energy used by the electrolysis unit comes from the electric energy generated by the waste heat of the ship's exhaust gas, without additional input of electric energy, which greatly saves the cost of ship exhaust gas treatment, and truly achieves the purpose of treating the waste gas with the waste heat of the exhaust gas itself.

2. The present invention treats diesel engine exhaust gas by using its own waste heat to generate electricity, so it can be processed on-line. That is, as long as the marine diesel engine runs to generate exhaust gas, the system will use the waste heat of the exhaust gas to generate electric energy to treat the exhaust gas; when the working condition of the diesel engine changes, the amount of exhaust gas will also change, resulting in a decrease in power generation and lye output of the electrolyzer. change.

3. For ships, the seawater with high salt concentration produced by the ship's seawater desalination system is also a resource, and it is also a waste of resources if it is directly discharged into the sea. The invention achieves the purpose of treating waste by using the waste by electrolysis, and the pH value of the waste liquid after waste gas treatment is similar to that of seawater, and can be directly discharged into the sea.

4. The present invention makes full use of the seawater with high concentration produced by the ship's seawater desalination system to improve the chlorine production of ballast water treated by electrolysis, and at the same time, the lye produced by the electrolysis unit is added to the sprayed seawater of the seawater waste gas desulfurization system , which increases the alkalinity of seawater, greatly reduces the consumption of seawater, and reduces the electric energy required for pumping seawater.

Description of drawings

The present invention has 3 accompanying drawings, wherein:

Figure 1 is a schematic diagram of a marine diesel engine exhaust gas treatment and utilization device;

Fig. 2 is a structural diagram of an electrolytic unit;

Fig. 3 is a schematic diagram of the organic Rankine cycle;

In the figure: 1. Marine diesel engine, 2. Turbocharger, 3. Flue gas heat exchanger, 4. Washing tower, 5. Alkali supply pump, 6. Mixing cabinet, 7. Alkali cabinet, 8. Electrolysis unit , 9. Storage battery, 10. Generator, 11. Organic Rankine cycle unit, 12. Aeration tank, 13. Seawater spraying device, 80. Seawater desalination system, 81. Filling pump, 82. Seawater supply pump, 83 , buffer cabinet, 84, electric heater, 85, sea water supply pump, 86, electrolyzer, 87, ion exchange membrane, 110, circulation pump, 111, cylinder jacket water heat exchanger, 112, evaporator, 113, expander , 114, condenser.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. As shown in Figures 1-3, when the present invention is working, the exhaust gas from the marine diesel engine 1 is discharged from the marine diesel engine 1, first passes through the turbocharger 2 to perform work, and then enters the organic Rankine cycle through the control of the bypass baffle V1/V2/V3 Unit 11. In the organic Rankine cycle unit 11, part of the energy of the exhaust gas of the marine diesel engine 1 is converted into electrical energy and stored in the storage battery 9. The storage battery 9 directly supplies power to the electrolysis unit 8, and at the same time also supplies power to the lye supply pump 5; the chlorine gas produced by the anode of the electrolysis unit 8 is supplied to the ballast tank of the ship through the valve V8, and is used to kill microorganisms in the ballast water; the electrolysis unit 8 The hydrogen produced by the cathode can be fed into the kitchen through the valve V7 as fuel, and the lye produced by the cathode of the electrolysis unit 8 is transported and stored in the lye cabinet 7 through the pipeline and the valve V9. The lye and seawater produced by the electrolysis unit 8 are fully mixed in the mixing cabinet 6, and then pumped by the lye supply pump 5 to the washing tower 4 to treat the exhaust gas of the diesel engine. If the lye produced by the electrolysis unit 8 is not enough to treat the exhaust gas of the diesel engine well, it can be replenished through the supply port on the lye cabinet 7 . The waste liquid after treating the diesel exhaust gas is stored in the aeration tank 12, and the aerated seawater can be discharged into the sea through the valve V10.

The exhaust gas of the marine diesel engine 1 can perform power generation in the organic Rankine cycle unit 11 and at the same time realize the first-time cooling of the exhaust gas of the diesel engine; The second cooling of the exhaust gas, while heating the exhaust gas after desulfurization treatment, so as to be discharged; the exhaust gas after heat exchange passes through the seawater spraying device 13 to further reduce the temperature of the exhaust gas of the diesel engine, and the sufficiently low temperature can greatly improve the washing tower 4 Medium exhaust gas desulfurization efficiency.

The organic Rankine cycle unit 11 uses exhaust gas from the marine diesel engine 1 to heat the jacket water of the diesel engine through the jacket water heat exchanger 111. The temperature is raised from 80-90°C to about 90-105°C. The heated jacket water of the diesel engine exchanges heat with the organic working medium in the organic Rankine cycle in the evaporator 112, and the cooled jacket water circulates back to the diesel engine, and the heated organic working medium that becomes gaseous is sent to the expander 113 The work done by the middle expansion is converted into electrical energy by the generator 10 and stored in the accumulator 9 . The organic working fluid after work is transported to the condenser 114 and condensed back to the liquid phase. The liquid-phase organic working fluid is pumped again by the circulation pump 110 to the evaporator 112 for heat exchange, and the cycle repeats.

The electrolysis unit 8 is to pump the seawater with high salinity concentration produced by the ship's seawater desalination system 80 into the buffer cabinet 83 through the liquid feeding pump 81, and the bottom of the buffer cabinet 83 is evenly distributed with electric heaters 84 pairs of buffer cabinets 83 The seawater in the water is preheated. After the seawater is heated to a suitable temperature, it is transported to the electrolytic cell 86 for electrolysis through the seawater supply pump 82. The electrolytic cell 86 is provided with an ion exchange membrane 87. When in use, seawater can be supplied to the buffer tank 83 through the seawater supply pump 85 and the valve V11. The chlorine gas produced by the anode of the electrolytic cell 86 is transported to the ballast tank of the ship through the valve V8 to kill microorganisms in the ballast water; the lye produced by the negative electrode of the electrolytic cell 86 is transported to the lye tank 7 through the valve V9 to treat the exhaust gas of the diesel engine. Processing; the hydrogen produced can be sent to the galley via valve V7 for fuel.

Claims (2)

1. a boat diesel engine waste gas treatment and utilized device, it is characterized in that: comprise machine exhaust treatment system, power generation system using waste heat and electrolysis system, described power generation system using waste heat comprises organic Rankine bottoming cycle unit (11), generator (10) and storage battery (9), and described organic Rankine bottoming cycle unit (11) is connected with diesel pressure booster by fume pipe; Described organic Rankine bottoming cycle unit (11) comprises recycle pump (110), vaporizer (112), decompressor (113), condenser (114) and jacket water heat exchanger (111); The high temperature side of described jacket water heat exchanger (111) connects with diesel exhaust, low temperature side and diesel cylinder sleeve aqueous phase connect, and described recycle pump (110) connects and composes circulation with vaporizer (112), decompressor (113), condenser (114) by pipeline successively; Flange joint is passed through between described decompressor (113) and generator (10); Described generator (10) is connected with electrolysis cells (8) through storage battery (9) by cable; Described electrolysis system comprises electrolysis cells (8), alkali lye cabinet (7), mixing cabinet (6) and alkali lye supply pump (5); Described electrolysis cells (8) cathode outlet is connected by pipeline with alkali lye cabinet (7); Alkali lye cabinet (7) outlet is connected by pipeline with sea water mixing cabinet (6); Mixing cabinet (6) is connected with scrubber tower (4) through alkali lye supply pump (5) by pipeline; Described electrolysis cells (8) comprises the marine sea water desalination device system (80), fluid filling pump (81), electric heater (84), buffer tank (83), sea water supply pump (82), seawater replenishment pump (85) and electrolytic bath (86); Seawater desalination system (80), fluid filling pump (81), buffer tank (83), sea water supply pump (82) are connected by pipeline successively with electrolytic bath (86); Seawater replenishment pump (85) is connected with buffer tank (83) by valve; Electric heater (84) is evenly arranged in buffer tank (83) bottom; Described exhaust treatment system comprises flue gas heat-exchange unit (3), scrubber tower (4), seawater spraying device (13) and aeration tank (12); All be connected by fume pipe between flue gas heat-exchange unit (3) and scrubber tower (4), between flue gas heat-exchange unit (3) and seawater spraying device (13), seawater spraying device (13) is connected with aeration tank (12) by pipeline with scrubber tower (4).

2. a method of work for boat diesel engine waste gas treatment and utilized device, is characterized in that: comprise the following steps:

After A, boat diesel engine (1) waste gas are discharged by turbosupercharger (2), first organic Rankine bottoming cycle unit (11) is entered through by-pass baffles, in organic Rankine bottoming cycle unit (11), utilize the waste heat of diesel exhaust to generate electricity, and by sent electrical power storage in storage battery (9), reach the object of store electrical energy;

B, organic Rankine bottoming cycle unit (11) first utilize the heat in boat diesel engine (1) waste gas that diesel cylinder sleeve water is heated to 90-150 DEG C, and the jacket water after heating carries out heat exchange with organic working medium in vaporizer (112); Diesel cylinder sleeve water circulation after heat exchange returns main frame; Entered into decompressor (113) by the organic media heated and carry out expansion work, organic media after acting is cooled in condenser (114), cooled organic working medium is again recycled pump (110) and sends back in vaporizer (112) and carry out heat exchange, iterative cycles like this;

C, storage battery (9) are powered to electrolysis cells (8) by wire, alkali lye supply pump (5) power supply returned by storage battery (9) simultaneously, dump energy in storage battery (9), then power to other consumers of boats and ships;

D, electrolysis cells (8) carry out electrolysis to the high concentration seawater that the marine sea water desalination device system (80) produces, the chlorine that electrolysis cells (8) anode produces passes into ballast tank of ship for the treatment of ballast water for ship, the alkali lye that electrolysis cells (8) negative electrode produces is carried and is stored in alkali lye cabinet (7), and the hydrogen of generation is transported to kitchen and is used as fuel;

After the discharge of E, boat diesel engine (1) waste gas while organic Rankine bottoming cycle generating, realize the first time cooling of diesel exhaust, secondly waste gas later with desulfurization process in flue gas heat-exchange unit (3) carries out heat exchange, realizes the second time cooling of diesel exhaust; Third time cooling is carried out again entering into before spray tower carries out desulfurization process through a seawater spraying;

Spray tower delivered to by the mixture pump of the alkali lye that electrolysis cells (8) produces by F, alkali lye supply pump (5) and seawater, the diesel exhaust after cooling delivered to spray tower simultaneously, carries out spray process;

G, waste gas after spray tower process carry out heating up after heat exchange discharge through flue gas heat-exchange unit (3).