CN206522176U

CN206522176U - Boat diesel engine catalytic reduction device with NOx trap function

Info

Publication number: CN206522176U
Application number: CN201621457306.0U
Authority: CN
Inventors: 刘腾
Original assignee: Hudong Heavy Machinery Co Ltd; China Shipbuilding Power Engineering Institute Co Ltd
Current assignee: Hudong Heavy Machinery Co Ltd; China Shipbuilding Power Engineering Institute Co Ltd
Priority date: 2016-12-28
Filing date: 2016-12-28
Publication date: 2017-09-26
Anticipated expiration: 2026-12-28

Abstract

One kind has NO_xTrap the marine diesel catalytic reduction device of function, including upstream inlet pipe, downstream inlet pipe, blast pipe, NO_xTrap, air-out apparatus, urea jet pipe and selective catalysis reduction tank body, the utility model need not be heated by external heat source to catalytic reduction device, solve boat diesel engine NO under starting initial stage and running on the lower load_xThe problem of discharge.

Description

With NOxTrap the boat diesel engine catalytic reduction device of function

Technical field

The utility model, which is related to diesel emission contamination control, particularly one kind, can reduce boat diesel engine at the beginning of starting NO under phase or low-load operating mode_xThe catalytic reduction device of discharge.

Background technology

Engine of boat and ship is main based on diesel engine, although the fast development of diesel engine promotes international ocean shipping industry rapid Grow, but the pollution that boat diesel engine emission is caused causes very havoc to global environment.Therefore International Maritime Organization The requirement discharged for boat diesel engine is increasingly strict, especially NO_x.Ship NO is reduced at present_xThe main method of discharge just like Under it is several：One is fuel oil control technology, and two be combustion control technology, and three be air inlet control technology, and four be selective catalysis reduction skill Art (Selective Catalytic Reduction, hereinafter referred to as SCR).Wherein Section 4 technology belongs to external purification skill Art, is widely used in the exhaust aftertreatment of boat diesel engine.

Selective catalysis reduction technique refers to using catalyst in the presence of oxygen, using reducing agent selectively will NO in waste gas_xIt is reduced into N₂And H₂O is to reduce NO_xDischarge.Current most of SCR system uses urea as reducing agent, NH is hydrolyzed to form by the evaporation of urea liquid, pyrolysis and intermediate product HNCO₃To reduce NO_x。

But, the catalysis reducing material optimal reaction temperature that the technology is used is general in the range of 280~420 DEG C, Boat diesel engine is started under initial stage or low-load operating mode, and SCR device is often unable to reach this temperature.With MAN companies Exemplified by 6S350MEB diesel engines, delivery temperature is 280 DEG C under its 25% load, only up to activation of catalyst threshold temperature, because This can not make SCR device play a role initial stage in starting, the NO not being cleaned_xIt will be directly discharged into air.If using heating Stove helps SCR device to be rapidly heated, then needs to consider extra device layout, while increasing energy expenditure.

Utility model content

The purpose of this utility model is, overcomes the shortcomings of that above-mentioned spot ship diesel SCR technology has there is provided one kind NO_xThe boat diesel engine catalytic reduction device of function is trapped, NO under initial stage or low-load operating mode is started to reduce boat diesel engine_x Discharge.

The utility model is achieved through the following technical solutions：

One kind has NO_xTrap the marine diesel catalytic reduction device of function, its feature be to include upstream inlet pipe, Downstream inlet pipe, blast pipe, NO_xTrap, air-out apparatus, urea jet pipe and selective catalysis reduction tank body, described NO_xTrapping Device and air-out apparatus are encapsulated in the central bottom that selective catalysis reduces tank body, described NO up and down_xTrap is through described Air-out apparatus leads to described selective catalysis reductive jar body phase, and described urea jet pipe is evenly arranged in described selective catalysis also On the bottom surface of former tank body, described upstream inlet pipe reduces tank body after being connected with downstream inlet pipe through described selective catalysis Top and with described NO_xTrap is connected, and described blast pipe is connected with the top of described selective catalysis reduction tank body, If described selective catalysis reduction tank interior arrangement dried layer catalyst.

Described downstream inlet pipe has higher thermal conductivity factor, the heat in tail gas can be passed to catalysis also rapidly Catalyst in former tank body.

Described NO_xIts interior is carrier, the NO equipped with de- BaZSM-5 or NaZSM-5 molecular sieves are efficiently inhaled_xCatch Adsorbent coating is scribbled on the inwall of storage rapidly to adsorb NO in low temperature_x, and taken off at a temperature of higher than 280 DEG C Attached NO_x。

Described urea jet pipe is in described NO_xWhen trap reaches desorption temperature, it will be reduced to selective catalysis in tank body Spray urea liquid.

Upstream and downstream air inlet pipe and NOx trap are encapsulated in selective catalysis reduction tank base, diesel engine starting initial stage During high-temperature tail gas enters NOx trap from upstream and downstream air inlet pipe, the catalyst in selective catalysis reductive jar body is carried out Heating, helps it to be rapidly reached optimal catalytic temperature；NOx trap is adsorbed to the NOx in tail gas simultaneously, and trap Temperature also lifted simultaneously, when reaching suitable temperature, NOx in trap desorption, and with urea liquid pyrolysis gas NH3 Into in the catalyst for reaching activation temperature, catalytic reduction reaction is completed, boat diesel engine is finally reached and starts initial stage or low negative Carry the purpose that NOx emission is reduced under operating mode.

NO of the present utility model_xTrapping technique principle is：The use of BaZSM-5 or NaZSM-5 molecular sieves is carrier, this kind of point Sub- sifter device has uniform micropore, larger specific surface area and pore volume, and micropore size is about NO_x2~6 times of molecular diameter, And with alkali ion Ba²⁺Or Na⁺, make it can be to NO at 30 DEG C~350 DEG C_xPreferably adsorbed；Importantly, this kind of Molecular sieve is stronger due to adsorption capacity, so desorption temperature is also often higher than the activation temperature (280 DEG C) of catalyst.In addition, can Increase adsorbent coating on carrier to improve molecular sieve to NO_xAbsorption property, adsorbent coating is contemplated that using such as CaO-Beta etc can be directed to NO at a lower temperature_xCarry out physics and the material of chemisorbed.

Good effect of the present utility model is：

NO can be trapped using molecular sieve and adsorbent coating_xDischarge, and it is anti-using exhaust temperature heating selective catalysis reduction Answer required catalyst temperature, and Proper Match urea liquid time for spraying and start initial stage or low negative to reduce boat diesel engine Carry the NO under operating mode_xDischarge, compared with common SCR device, have simple in construction, cost it is low, do not need additional energy it is excellent Point.

Brief description of the drawings

Fig. 1 is the utility model boat diesel engine catalytic reduction device schematic appearance；

In figure：1- upstream inlets pipe, 3- blast pipes, 6- urea jet pipe (lower end), 7- selective catalysis reduction tank body.

Fig. 2 is the utility model boat diesel engine catalytic reduction device internal structure schematic diagram；

In figure：2- downstream inlets pipe, 4-NO_xTrap, 5- air-out apparatus, 6- urea jet pipe (entirety), 8- catalyst.

Fig. 3 is molecular sieve adsorption NO_xSchematic diagram；Wherein (a) is adsorption molecule in the fluid boundary film of particle surface Diffusion, (b) is pore diffusion and the diffusion into the surface of adsorption molecule, and (c) is the absorption that adsorption molecule is attracted in pore Point on.

Fig. 4 is molecular sieve or catalyst carrier and coating structure schematic diagram, wherein it is that (b) is (a) that (a), which is honeycomb pass, Partial enlarged drawing, (c) be spherical particles type, (d) be (c) partial enlarged drawing.

Embodiment

Below in conjunction with Figure of description, the utility model is described in further detail.

Fig. 1 is the utility model boat diesel engine catalytic reduction device schematic appearance, and Fig. 2 is the utility model ship bavin The internal structure schematic diagram of oil machine catalytic reduction device, as seen from the figure, the utility model has NO_xTrap the marine diesel oil of function Machine catalytic reduction device, including upstream inlet pipe 1, downstream inlet pipe 2, blast pipe 3, NO_xTrap 4, air-out apparatus 5, urea Jet pipe 6 and selective catalysis reduction tank body 7, described NO_xTrap 4 and air-out apparatus 5 are encapsulated in described selective catalysis also Bottom in former tank body 7, described NO_xTrap 4 is communicated through described air-out apparatus 5 with described selective catalysis reduction tank body 7, Described urea jet pipe 6 is evenly arranged on the bottom of described selective catalysis reduction tank body 7, the described He of upstream inlet pipe 1 Downstream inlet pipe 2 through selective catalysis reduce tank body 7 top and with described NO_xTrap 4 is connected, described blast pipe 3 Connected with the top of described selective catalysis reduction tank body 7, if internal arrangement dried layer in described selective catalysis reduction tank body 7 Catalyst 8.

Upstream inlet pipe 1, blast pipe 3 and urea jet pipe 6 are sealingly mounted on selective catalysis reduction tank body 7, tail gas warp Cross and enter NO after downstream inlet pipe 2_xIn trap 4, both exterior materials all have good thermal conductivity, can make tail gas in stream Catalyst 8 while dynamic in quick heating selective catalysis reduction tank body 7, now flows out NO_xDo not contained in the gas of trap 4 NO_x, and catalyst 8 can also be heated.NO_xThe desorption temperature of trap 4 is general more than 350 DEG C, now catalyst 8 temperature is approximate therewith, interval interior between catalyst optimal reaction temperature；Now from NO_xThe NO being desorbed in trap 4_xFlow through institute The air-out apparatus 5 stated, the urea liquid sprayed with urea jet pipe 6 meets；Urea liquid is mainly sent out in the presence of high-temperature tail gas Give birth to row (1)~(4) chemical reaction, substantial amounts of NO after reaction_xIt is cleaned, enters through blast pipe 3 in booster.

(1) urea liquid evaporates：

(NH₂)₂CO(aq)→(NH₂)₂CO(lorg)+6.9H₂O(g)

(2) urea pyrolysis：

(NH₂)₂CO(lorg)→NH₃(g)+HNCO(g)

(3) hydrogen cyanide is hydrolyzed：

HNCO(g)+H₂O(g)→NH₃(g)+HNCO(g)

(4) catalytic reduction reaction：

4NH₃+4NO+O₂→4N₂+6H₂O

4NH₃+2NO+2NO₂→4N₂+6H₂O

4NH₃+6NO→5N₂+6H₂O

4NH₃+3NO₂→3.5N₂+6H₂O

Fig. 3 is molecular sieve adsorption NO_xSchematic diagram, absorption is broadly divided into three root phases：

(a) it is that adsorption molecule spreads in the fluid boundary film of particle surface；

(b) be adsorption molecule pore diffusion and diffusion into the surface, pore diffusion is adsorption molecule in the inside of pore Diffusion, diffusion into the surface is that the adsorption molecule on hole wall is transferred to adjacent absorption on the wall in hole from an adsorption potential On position；

(c) it is that adsorption molecule is attracted on the adsorption site in pore.

It in the schematic diagram of molecular sieve or catalyst carrier and coating structure, figure 9 is BaZSM-5 or NaZSM-5 points that Fig. 4, which is, Son sieve carrier, 10 be adsorbent coating, and top figure is honeycomb pass, and its sorbent coated is in the inwall of carrier hole, this honeycomb Shape passage considerably increases contact of the waste gas with adsorbent, and reduces back pressure, with preferable purifying property；Lower section figure is ball Body granular pattern, its adsorbent is coated in the surface of spherical particle carrier, and this spherical particle specific surface area is larger, it is easy to load, Price is also more cheap.Trap or catalysis reductor often are arranged using this two classes mode in practice, but needs consideration two The vapour lock for planting packed bed generation is rationally designed.

Claims

1. one kind has NO_xTrap function marine diesel catalytic reduction device, it is characterised in that including upstream inlet pipe (1), Downstream inlet pipe (2), blast pipe (3), NO_xTrap (4), air-out apparatus (5), urea jet pipe (6) and selective catalysis reductive jar Body (7), described NO_xTrap (4) and air-out apparatus (5) are encapsulated in the centre of described selective catalysis reduction tank body (7) Bottom, described NO_xTrap (4) reduces tank body (7) through described air-out apparatus (5) and described selective catalysis and communicated, institute The urea jet pipe (6) stated is evenly arranged on the bottom surface of described selective catalysis reduction tank body (7), described upstream inlet pipe (1) and downstream inlet pipe (2) through selective catalysis reduce tank body (7) top and with described NO_xTrap (4) is connected, institute The blast pipe (3) stated is connected with the top of described selective catalysis reduction tank body (7), described selective catalysis reduction tank body (7) If middle internal arrangement dried layer catalyst (8).

2. marine diesel catalytic reduction device according to claim 1, it is characterised in that described downstream inlet pipe (2) With higher thermal conductivity factor, the heat in tail gas can be passed to the catalyst in described catalysis reduction tank body rapidly.

3. marine diesel catalytic reduction device according to claim 1, it is characterised in that described NO_xIn trap (4) Portion is equipped with BaZSM-5 the or NaZSM-5 molecular sieve carriers (9) for efficiently inhaling de- function, the NO_xScribbled on the inwall of trap (4) Adsorbent coating (10), can rapidly adsorb NO in low temperature_x, and it is desorbed NO at a temperature of higher than 280 DEG C_x。

4. marine diesel catalytic reduction device according to claim 1, it is characterised in that described urea jet pipe is in institute The NO stated_xWhen trap reaches desorption temperature, urea liquid is sprayed by being reduced to described selective catalysis in tank body.