CN211038785U

CN211038785U - Reducing agent supply and metering device of SCR (selective catalytic reduction) system of marine diesel engine

Info

Publication number: CN211038785U
Application number: CN201921763898.2U
Authority: CN
Inventors: 张占虎; 包东明; 沈建华; 靖海国
Original assignee: CSSC Marine Power Co Ltd
Current assignee: CSSC Marine Power Zhenjiang Co Ltd
Priority date: 2019-10-21
Filing date: 2019-10-21
Publication date: 2020-07-17
Anticipated expiration: 2029-10-21

Abstract

The utility model discloses a marine diesel SCR system reductant supply and metering device, including reductant supply and metering unit, compressed air conveying unit and P L C controller, reductant supply and metering unit include the filter, the pressure release check valve, the diaphragm pump, automatically controlled tee bend relief valve, the buffer tank, first pressure sensor, fluid flowmeter, automatically controlled opening valve, first electromagnetism two-way valve and automatically controlled tee bend change-over valve, compressed air conveying unit includes the relief pressure valve, second pressure sensor, second electromagnetism two-way valve and third electromagnetism two-way valve, the signal line of P L C controller links to each other with corresponding pump, valve respectively, the utility model discloses integrated reductant supply and metering unit and compressed air conveying unit, but the jet mass of accurate control reductant, improve the denitration effect of tail gas, can also dredge the jet valve cavity effectively and can cool off the jet valve, prevent high temperature damage the jet valve, improve the reliability of jet valve work.

Description

Reducing agent supply and metering device of SCR (selective catalytic reduction) system of marine diesel engine

Technical Field

The utility model relates to a conveyor of diesel engine SCR system reductant, in particular to urea solution when marine diesel tail gas denitration treatment carries and metering device belongs to internal-combustion engine environment-friendly device technical field.

Background

With the continuous enhancement of the environmental awareness of the whole society, relevant regulations related to the international organization for limiting the pollutant emission of the marine diesel engine are increasingly strict, and particularly, the enforcement of the Tier III regulation of the international maritime organization for reducing the nitrogen oxide emission of ships is carried out, and more ships are additionally provided with an SCR (catalytic reduction) system. The SCR system is used for treating the denitration pollution of the tail gas of the diesel engine, can reduce nitrogen oxides in the tail gas, and has the advantages of high treatment efficiency, no influence on the performance and efficiency of the engine and the like. However, in the actual use process, whether the supply and the metering of the reducing agent (urea solution) are reliable or not has a great influence on the denitration effect of the tail gas, and if the urea solution is sprayed too much, the ammonia content in the tail gas is too high, which also pollutes the atmosphere; if the urea solution is not sprayed enough, the tail gas is not denitrified completely, and the reduction of the nitrogen oxides in the tail gas cannot meet the relevant requirements. Therefore, a set of simple and reliable reducing agent supply and metering device is developed, and the device plays a vital role in improving the system reliability, ensuring the tail gas denitration efficiency and reducing the ammonia escape.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a marine diesel SCR reductant system supply and measurement integrated device to solve the technical defect that reductant supply pressure is unstable, the measurement is inaccurate to lead to.

The utility model discloses a following technical scheme realizes:

a reducing agent supply and metering device of a marine diesel engine SCR system comprises a reducing agent supply and metering unit, a compressed air conveying unit and a P L C controller, wherein the reducing agent supply and metering unit comprises a filter, a pressure relief check valve, a diaphragm pump, an electric control three-way pressure relief valve, a buffer tank, a first pressure sensor, a fluid flowmeter, an electric control opening valve, a first electromagnetic two-way valve and an electric control three-way switching valve, the compressed air conveying unit comprises a pressure relief valve, a second pressure sensor, a second electromagnetic two-way valve and a third electromagnetic two-way valve, a reducing agent input A port of the reducing agent supply and metering unit is sequentially connected with the diaphragm pump, the electric control three-way pressure relief valve, the buffer tank, a fluid flowmeter, the electric control opening valve and a first input end of the electric control three-way switching valve through the filter, an output end of the electric control three-way switching valve enters an inner channel of an injection valve through a D port, a second end of the pressure relief check valve and a second end of the three-way pressure relief valve are respectively connected in parallel, compressed air is sequentially input through an input B port of the compressed air conveying unit and then is divided into two paths, the pressure relief valve, the first electromagnetic two-path of the reducing valve and the second electromagnetic three-way valve, the reducing agent supply and the second electromagnetic three-way valve are connected with a connecting.

The purpose of the utility model is further realized through the following technical scheme:

furthermore, the signal line of the P L C controller is electrically connected with the electric control three-way pressure release valve, the first pressure sensor, the second pressure sensor, the fluid flow meter, the diaphragm pump, the electric control opening valve, the electric control three-way pressure release valve, the electric control three-way switching valve, the first electromagnetic two-way valve, the second electromagnetic two-way valve and the third electromagnetic two-way valve respectively.

Further, the maximum flow rate of the diaphragm pump is 60L/h, and the diaphragm pump has the self-sucking capacity that the sucking height is lower than 1.5 m.

Furthermore, the air pressure of the compressed air input from the port B is 600-800 Kpa.

The utility model discloses compact structure, it is small, reductant supply and metering unit and compressed air conveying unit have been integrated, and realize the PID closed-loop control to reductant supply, measurement and compressed air transport through P L C controller, the pressure release check valve and the automatically controlled tee bend relief valve that set up in reductant supply and metering unit's the reductant supply circuit make the transport of reductant have the function of two backward flows, the pressure fluctuation that produces among the reductant transportation process has been avoided effectively, ensure the homogeneity of the pressure and the flow that the reductant was carried, marine diesel engine tail gas's denitration effect has been improved, through the experiment of the measurement of fluidflowmeter with each component of reductant supply and metering unit, and the closed loop of P L C controller, can accurately control the injection volume of reductant, thereby effectively ensure the denitration efficiency of tail gas, reduce the escape of ammonia greatly, switch over through the case position of automatically controlled tee bend change-over valve, can switch over to the compressed air transport into the injection valve cavity when need not spouting urea, can dredge the injection valve cavity effectively and can cool off the injection valve, prevent high temperature damage injection valve, improve the reliability of injection valve work.

The advantages and features of the invention will be illustrated and explained by the following non-restrictive description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and embodiments of the reducing agent supply and metering device for the SCR system of a medium speed diesel engine for a ship.

As shown in fig. 1, the present embodiment includes a reducing agent supply and metering unit 1, a compressed air delivery unit 2, and a P L C controller 3, where the reducing agent supply and metering unit 1 includes a filter 11, a pressure relief check valve 12, a diaphragm pump 13, an electrically controlled three-way pressure relief valve 14, a buffer tank 15, a first pressure sensor 16, a fluid flow meter 17, an electrically controlled opening valve 18, a first electromagnetic two-way valve 19, and an electrically controlled three-way switching valve 110, and the compressed air delivery unit 2 includes a pressure relief valve 21, a second pressure sensor 22, a second electromagnetic two-way valve 23, and a third electromagnetic two-way valve 24.

The reducing agent input port A of the reducing agent supply and metering unit 1 is sequentially connected with a diaphragm pump 13, an electric control three-way pressure release valve 14, a buffer tank 15, a fluid flowmeter 17, an electric control opening valve 18 and a first input end 1101 of an electric control three-way switching valve through a filter 11, an output end 1103 of the electric control three-way switching valve enters an injection valve inner channel 41 through a port D, an output end 131 of the diaphragm pump and an input end 111 of the filter are respectively connected in parallel with a pressure relief check valve 12 and a second end 141 of the electric control three-way pressure release valve, the two parallel circuits enable conveying of the reducing agent to have a double backflow function, pressure fluctuation generated in the conveying process of the reducing agent is effectively avoided, the maximum flow rate of the diaphragm pump 13 is 60L/h, the diaphragm pump.

The compressed air conveying unit 2 comprises a pressure reducing valve 21, a second pressure sensor 22, a second electromagnetic two-way valve 23 and a third electromagnetic two-way valve 24, compressed air is input through an input port B of the compressed air conveying unit 2 and then is divided into two paths, and one path is connected with a second input end 1102 of the electric control three-way conversion valve through the pressure reducing valve 21 and the third electromagnetic two-way valve 24 in sequence; the other path passes through the pressure reducing valve 21, is connected with the port C through the second electromagnetic two-way valve 23, and then enters the injection valve outer channel 41.

The first pressure sensor 16 is connected to a connection pipeline between a fluid flow meter 17 and a buffer tank 15 of the reducing agent supply and metering unit in a bypassing manner, and is used for detecting the pressure of the urea solution before entering the fluid flow meter 17, transmitting a detected pressure signal to the P L C controller 3, and the P L C controller 3 sends a feedback signal to the electrically-controlled opening valve 18 and the fluid flow meter 17, so as to adjust the opening of the electrically-controlled opening valve 18 and improve the denitration effect of the marine diesel exhaust gas.

The horizontal distance between the installation position of the utility model and the reducing agent storage tank is not more than 20m, and the vertical distance is not more than 1.5 m; the horizontal distance from the injection valve cannot exceed 5m and the vertical distance cannot exceed 2 m. The reducing agent is conveniently sprayed into the tail gas through the injection valve to carry out denitration treatment on the tail gas.

The working process of the utility model is as follows:

after a diaphragm pump 13 of the reducing agent supply and metering unit 1 is started, a reducing agent (urea solution) stored in a reducing agent storage tank 1 is stored in a buffer tank 15 from a reducing agent input port A through a filter 11 and an electric control three-way pressure release valve 14, wherein a pressure release check valve 12 and the electric control three-way pressure release valve 14 which are respectively connected between the diaphragm pump 13 and the filter 11 in parallel have a double backflow function, and the action of the buffer tank 15 can effectively avoid pressure fluctuation generated in the conveying process of the reducing agent.

The compressed air with the pressure of 600-800 Kpa output from the compressed air storage tank is input through a port B of the compressed air conveying unit 2 and then divided into two paths, one path is decompressed to the pressure of 200-300 Kpa through a pressure reducing valve 21, and then enters an injection valve inner channel 42 after passing through a third electromagnetic two-way valve 24, a second input end 1102 of an electric control three-way conversion valve and a port D, the other path firstly passes through the pressure reducing valve 21, then enters an injection valve outer channel 41 after passing through a second electromagnetic two-way valve 23 and a port C, when the blocked injection valve needs to be opened, a P L C controller 3 instructs a valve core of the electric control three-way conversion valve 110 to move to close a first input end 1101 of the electric control three-way conversion valve, and the path of the urea solution input to the electric control three-way conversion valve 110 is cut off, at the moment, the compressed air enters the port C and the port D to respectively pass through.

In addition to the above embodiments, the present invention can also have other embodiments, and all technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A reducing agent supply and metering device of a marine diesel engine SCR system is characterized by comprising a reducing agent supply and metering unit, a compressed air conveying unit and a P L C controller, wherein the reducing agent supply and metering unit comprises a filter, a pressure relief check valve, a diaphragm pump, an electric control three-way pressure relief valve, a buffer tank, a first pressure sensor, a fluid flowmeter, an electric control opening valve, a first electromagnetic two-way valve and an electric control three-way switching valve, the compressed air conveying unit comprises a pressure relief valve, a second pressure sensor, a second electromagnetic two-way valve and a third electromagnetic two-way valve, a reducing agent input A port of the reducing agent supply and metering unit is sequentially connected with the diaphragm pump, the electric control three-way pressure relief valve, the buffer tank, the fluid flowmeter, the electric control opening valve and a first input end of the electric control three-way switching valve through the filter, an electric control three-way pressure relief valve output end enters an injection valve inner channel through a D port, the pressure relief check valve and a second end of the electric control three-way pressure relief valve are respectively connected in parallel, compressed air is input through an input B port of the compressed air conveying unit and then divided into two channels, one channel is connected with a second input end of the electromagnetic three-way switching valve, the reducing valve, the other electromagnetic two channels are sequentially connected with the fluid flowmeter of the electromagnetic two-way pressure relief valve, and.

2. The reducing agent supply and metering device for the SCR system of the marine diesel engine as defined in claim 1, wherein signal lines of the P L C controller are respectively electrically connected with the electrically-controlled three-way pressure relief valve, the first pressure sensor, the second pressure sensor, the fluid flow meter, the diaphragm pump, the electrically-controlled opening valve, the electrically-controlled three-way pressure relief valve, the electrically-controlled three-way switching valve, the first electromagnetic two-way valve, the second electromagnetic two-way valve and the third electromagnetic two-way valve.

3. The reductant supply and metering device for a marine diesel SCR system of claim 1, wherein the diaphragm pump has a maximum flow rate of 60L/h and a self-priming capability with a suction height of less than 1.5 m.

4. The marine diesel SCR system reductant supply and metering device of claim 1, wherein: the air pressure of the compressed air input from the port B is 600-800 Kpa.

5. The marine diesel SCR system reductant supply and metering device of claim 1, wherein: the air pressure of the compressed air output from the port C is 300-350 Kpa.