CN207591613U

CN207591613U - A kind of regenerated SCR system of low-temperature SCR catalyst

Info

Publication number: CN207591613U
Application number: CN201720403592.0U
Authority: CN
Inventors: 杨世超; 夏强; 毛成建
Original assignee: WAI MING ENVIRONMENTAL PROTECTION EQUIPMENT CO Ltd
Current assignee: WAI MING ENVIRONMENTAL PROTECTION EQUIPMENT CO Ltd
Priority date: 2017-04-17
Filing date: 2017-04-17
Publication date: 2018-07-10
Anticipated expiration: 2027-04-17

Abstract

The utility model discloses a kind of regenerated SCR systems of low-temperature SCR catalyst, including SCR reactors, the setting regeneration bypass between the inlet flue duct and exhaust pass of SCR reactors, the regeneration bypass includes electric heater, regeneration gas, which is electrically heated after device is heated to certain temperature, enters Reactor inlet flue, to the ammonium hydrogen sulfate deposited in catalyst surface and micropore（ABS）Carry out heating vaporization.

Description

A kind of regenerated SCR system of low-temperature SCR catalyst

Technical field

The utility model is suitable for the purification techniques of the gas cleaning denitration process, i.e. nitrogen oxides of waste incineration industry, The regenerated SCR system of specifically a kind of low-temperature SCR catalyst and its method.

Background technology

Centralized burning method is increasingly becoming the major way of China's urban garbage disposal, in the flue gas of waste incinerator Nitrogen oxides-- NOx (NO, the NO of certain content can be generated₂, N₂O, N₂O₃, N₂O₄, N₂O₅Wait the general designation of nitrogen oxides), with The enhancing of national environmental consciousness, with《Consumer waste incineration contamination control standard》(GB18485-2014) from January 1 in 2016 Day implements in full, and new requirement is proposed to domestic waste incineration fume treatment technology.It is generated in domestic waste incineration In atmosphere pollution, the purification of NOx is most difficult and expense most expensive technology, this is because inertia (being not susceptible to of NO Learn reaction) and be insoluble in water property decision, existing widely used fume treatment technology takes off for selective catalytic reduction Nitre-- SCR and selective non-catalytic reduction method denitration-- SNCR.

SCR (Selective Catalytic Reduction, be abbreviated as SCR) denitration technology refer in certain temperature and Under the action of catalyst, to contain amino (NH₃) liquefied ammonia or ammonium hydroxide as reducing agent, selectively with the nitrogen oxidation in flue gas Object carries out reduction reaction, and generates nontoxic, free of contamination N₂With the cleaning denitration technology of water.This technology is from the 1970s Since fuel oil, combustion gas, coal-fired power station boiler are applied first, popularization and technical research by more than 40 years, SCR at present Gas denitrifying technology has evolved into ripe in the world, and denitration efficiency can reach more than 90%.

Under conditions of catalyst is not added, the reaction temperature of ammonia and nitrogen oxides is 900 DEG C, if adding in catalyst, Reaction temperature can be reduced to 250 DEG C.Reducing agent NH₃With nitrogen oxides (NO and NO₂) surface reaction is carried out, reaction mechanism is as follows：

Catalyst generally selects TiO₂V for matrix₂O₅And WoO₃Mixture, specific formula are determined according to Gas Parameters.

There are mainly two types of modes for common SCR arrangements now：1st, SCR reactors are arranged in economizer exit and air preheater Between entrance, the flue-gas temperature into reactor is mainly characterized by the range of 300~400 DEG C, is suitable for most catalyst Reaction temperature requirement；The 2nd, SCR reactors are arranged in the downstream of deduster and flue gas desulfurization device, be mainly characterized by into The flue gas for entering reactor has been stripped of a large amount of flying dusts, is not easy to cause catalyst abrasion.

Mainly the second way, main flow are as shown in Figure 1 in the application of waste incinerator.

Fatal side reaction there are one influence catalyst activity in this flow is escape ammonia and cigarette in SCR denitration system SO in gas₃And water vapour generation ammonium hydrogen sulfate (ABS)：

SO₃+NH₃+H₂O---- → NH₄HSO₄

The dew point of ammonium hydrogen sulfate is 147 DEG C, assembles in body surface in liquid form or is scattered in cigarette with drops In gas.The ammonium hydrogen sulfate of liquid is a kind of very strong substance of viscosity, if it is formed on low temperature catalyst, can cause catalyst Partial Blocking increases catalyst pressure drop or causes catalyst failure.The deposition of ammonium hydrogen sulfate will occur first in the sky of catalyst In gap, the process of deposition is reversible, and when running temperature is promoted to more than dew point, ammonium hydrogen sulfate will evaporate, catalyst activity Restore, but running temperature, for a long time less than its dew point, catalyst activity will permanently change.

SCR system in actual use, since reaction temperature reduction can cause catalyst amount to increase, is catalyzed simultaneously Agent for a long time at low temperature operation can cause ammonium hydrogen sulfate deposition make catalyst poisoning, catalyst blockage of the micro orifice and lose activity, carry High reaction temperature then causes system investments and operating cost to occupy because flue gas reheats the problems such as energy consumption is higher, and heater friction is larger It is high not under.

Utility model content

In order to solve the above technical problems existing in the prior art, the utility model provides a kind of low-temperature SCR catalysis The regenerated SCR system of agent including SCR reactors, is set between the inlet flue duct and exhaust pass of SCR reactors by regeneration Road, the regeneration bypass include electric heater, and regeneration gas, which is electrically heated after device is heated to certain temperature, enters Reactor inlet cigarette Road carries out heating vaporization to the ammonium hydrogen sulfate (ABS) deposited in catalyst surface and micropore.

Further, the regeneration gas is using clean air, via manual damper, centrifugal blower, electric heater, Air is heated to by PLC control system by required temperature, after hot-air is by high temperature hose, regeneration flue, electric flap Into Reactor inlet flue.

Further, the NH after the ammonium hydrogen sulfate (ABS) is decomposed₃、SO₃Pass through the reactor outlet cigarette with water vapour Road, FlexbleJoint, electric flap, air-introduced machine enter chimney and are discharged to air.

Further, extracting tower, deduster are further included, boiler smoke is divided into two-way after extracting tower, deduster, all the way By being connect after electric flap, SGH heaters, ammonia-spraying grid with the inlet flue duct of SCR reactors, another way is SCR reactors Bypass, enters chimney by another electric flap, the air-introduced machine and is discharged to air.

The utility model has the following advantages that：

A) using the utility model, waste incinerator can be suitable for using the SCR system of low-temperature denitration catalyst technology Fume treatment, using its higher denitration efficiency, the effective guarantee qualified discharge of nitrogen oxides (NOx).

B) using the utility model, catalyst reaction temperatures when can be by SCR system normal operation are reduced to 160~ 180 DEG C, save a large amount of energy consumptions of flue gas reheating.

C) using the utility model, by catalyst regular regeneration, making its activation recovering, extending the use of catalyst Service life saves the expensive cost of more catalyst changeout.

D) using the utility model, catalyst can obtain more rapidly more easily safeguarding, reduce system-down when Between.

Description of the drawings

Fig. 1 is existing SCR system arrangement figure；

Fig. 2 is the regenerated SCR system structure chart of low-temperature SCR catalyst of the utility model.

Specific embodiment

The utility model is described in further detail below in conjunction with the accompanying drawings.

As shown in Fig. 2, the regenerated SCR system of the low-temperature SCR catalyst of the utility model, including SCR reactors, boiler smoke Gas is divided into two-way after extracting tower, deduster, all the way by being reacted after electric flap, SGH heaters, ammonia-spraying grid with SCR Device inlet flue duct connects, flue gas by purification by reactor outlet flue, FlexbleJoint, electric flap, air-introduced machine into Enter chimney and be discharged to air, another way is SCR reactor bypass, and entering chimney by another electric flap, the air-introduced machine arranges Go out to air.

Setting regeneration bypass, regeneration gas use clean air between Reactor inlet flue and exhaust pass, via Air is heated to required temperature by manual damper, centrifugal blower, electric heater by PLC control system, and hot-air leads to Enter Reactor inlet flue after crossing high temperature hose, regeneration flue, electric flap, to the sulphur deposited in catalyst surface and micropore Sour hydrogen ammonium (ABS) carries out heating vaporization, and by the circulating-heating of certain time, ammonium hydrogen sulfate evaporation becomes drop and is diffused into hot sky In gas or it is thermally decomposed into NH₃、SO₃And water vapour, then by the reactor outlet flue, FlexbleJoint, electric flap, Air-introduced machine enters chimney and is discharged to air.

The technological process of the utility model is as follows：The neutralized tower of flue gas from incineration plant boiler, deduster depickling, dedusting Enter SCR system later.It is divided into two-way in SCR system inlet flue gas, is all the way reactor bypass, directly arrives and draw through electric flap Wind turbine, for the guard catalyst in incinerator start and stop stove, spray ammonia standard is not achieved in flue-gas temperature at this time, and dust-laden water capacity is super The limit value of catalyst permission is crossed, setting bypasses the activity of energy effective protection catalyst, extends the service life of catalyst.Another way Through electric flap → steam-flue gas heater (SGH) → ammonia-spraying grid (be simultaneously from the ammonia of reducing agent preparation system with it is dilute Release to pass through after wind mixes in ammonia sky mixer and be sent into flue by ammonia-spraying grid) → Reactor inlet flue → FlexbleJoint → Baffle plate → flow deflector → enter reactor catalyst bed, in the microporous activated material surface NOx and NH of catalyst₃Chemistry occurs Reaction generation N₂And H₂O, the flue gas by purification pass through reactor outlet flue → FlexbleJoint → electric flap → air-introduced machine → chimney (online setting NOx and NH₃Instrument is detected, monitors amount of nitrogen oxides and the escaping of ammonia in real time) it is discharged into air.

The setting regeneration bypass between Reactor inlet flue and exhaust pass, regeneration gas is using clean air, warp By manual damper → centrifugal blower → enter electric heater import, air is heated to by automatic control system required Temperature from heater outlet → high temperature hose → regeneration flue → electric flap → Reactor inlet flue → FlexbleJoint → Baffle plate → flow deflector → enter reactor catalyst bed, to the ammonium hydrogen sulfate (ABS) deposited in catalyst surface and micropore Heating vaporization is carried out, by the circulating-heating of certain time, ammonium hydrogen sulfate evaporation becomes drop and is diffused into hot-air or is heated Resolve into NH₃、SO₃And water vapour, then pass through reactor outlet flue → FlexbleJoint → electric flap → air-introduced machine → chimney Air is discharged into, catalyst activity regeneration is realized, extends catalyst service life.

Hydrogen-catalyst reactor and regeneration heating device are combined together by being technically characterized in that for this system, anti-by setting It answers device bypass that catalyst regeneration function is fused in SCR system, can effectively solve the problem that encountered in low temperature catalyst use Catalyst module need to be taken out the complicated of SCR reactors and grasped by ammonium hydrogen sulfate moisture condensation problem when in turn avoiding previous catalyst regeneration Make.

The capital equipment of this system is configured to：Hydrogen-catalyst reactor (including baffle plate, flow deflector), electric flap, cigarette Gas-steam heater, ammonia-spraying grid, ammonia sky mixer, dilution air, manual air door, centrifugal blower, electric heater, ripple are mended Repay device, high temperature hose, flue, temperature and manometer, nitrogen oxides and ammonia analysis meter, PLC controller.

Capital equipment function describes：

1) SCR reactors：For placing catalyst, and pass through baffle plate, flow deflector adjusting flue gas flow field in the reactor Distribution, forms main denitration reaction space.

2) electric flap：It is main moving component, is used to implement flow and adjusts and exhaust gases passes switching.

3) flue gas-steam heater：For ensureing catalyst reaction temperatures to flue gas, set when flue-gas temperature is less than It is opened during definite value.

4) ammonia-spraying grid, ammonia sky mixer, dilution air：For reducing agent (NH₃) input, and make it uniform with flue gas Mixing, ensures suitable ammonia nitrogen molar ratio.

5) manual air door：Regeneration fresh air air inflow is adjusted, ensures the efficiency of heating surface and regeneration effect of circulation air.

6) centrifugal blower：For regenerating the air inlet of fresh air, the dynamic of regeneration gas circulating-heating catalyst in the reaction chamber is provided Energy.

7) electric heater：For heating regeneration fresh air to setting catalyst regeneration temperature, Removal of catalyst surface and micropore The ABS of middle deposition.

8) FlexbleJoint, high temperature hose, flue：For equipment connection, absorbing thermal expansion amount.

9) PLC controller, temperature and manometer：For the operation of each equipment and flow to be controlled to switch, ensure catalyst Denitration effect and regeneration effect, realize the automatic running of system.

10) nitrogen oxides and ammonia analysis meter：The content and the escaping of ammonia of NOx is detected, ensures that system reaches design objective.

Claims

1. a kind of regenerated SCR system of low-temperature SCR catalyst, including SCR reactors, it is characterised in that：SCR reactors into Setting regeneration bypass between mouthful flue and exhaust pass, the regeneration bypass include manual damper, centrifugal blower and electricity and add Hot device, PLC control system control electric heater, electric heater passes sequentially through after high temperature hose, regeneration flue, electric flap and institute State inlet flue duct connection；The exhaust pass connects after being sequentially connected FlexbleJoint, electric flap, air-introduced machine with chimney；Also Including extracting tower, deduster, deduster all the way by after electric flap, SGH heaters, ammonia-spraying grid with SCR reactors into Mouth flue connection, another way are SCR reactor bypass, enter the air-introduced machine by another electric flap, in incinerator Guard catalyst during start and stop stove.