Technology Discussion

August 6, 2012

Coal fired power plant SCR(Selective Catalytic Reduction) honeycomb denitrification catalyst

I. Introduction of China NH3 SCR technology

NOx emissions form coal fired power plant account for 80% of total industrial nitrogen oxides emissions; it is the main source of NOx pollution in China, strength the management of NOx emission is imperative.

At present, SCR(Selective Catalytic Reduction) for denitrification of nitrogen oxides in smokes is the mainstream technology in the world. SCR use reduction function of NH3 to NOx, under the condition of temperate between 320~400℃, that catalyst reduction happens change NOx to N2 and water which have no impact to the environment . “Selective” means NH3 only select NOx for reducing reaction.

In 2010, Ministry of Environmental Protection of China issue 《Technology policy regarding to power plant nitrogen oxides treatment》, it explicitly point out the nitrogen oxides not only is the import stuff form to ozone, but also is the important reason from district fine particle pollution and dust haze. At the same time, nitrogen oxides have great risk to human health as the primary pollutant.

In Sept 21 2011, Ministry of Environmental Protection of China enacted 《Standard for atmospheric Pollutant Discharge of power plant》, the laws determine the emission concentration of nitrogen oxides is 100mg/m3, execution time since 2012 for new generating sets while since July 2014 for old generating sets. All Chinese power plants should follow the standards.

30 Nov 2011, National Development and Innovation Committee of China enacted 《The State adopts a comprehensive measure to control coal and electricity price, explicitly point out since 1 Dec 2011, implement policy of price markup 0.8 yuan to every KWH for those coal fired power plants which have installed and normal use the SCR denitrification system.

The “upgraded” National Emission Standard will be the powerful driving force to control emission of coal fired power plant and improve China air quality and control Acid Rain Pollution. Along with prevalent of Selective Catalytic Reduction (SCR) technology, domestic research and develop SCR catalyst emerged, catalyst is the key of SCR system, its design and select is depend on smoke condition and smoke composition. Three interacting factor to catalyst design is NOx removal rate, NH3 escape rates and catalyst volume. The mainly 3 type of catalyst board type, honeycomb type and corrugated board type.

At present, domestic famous universities and colleges (such as NANKAI University, Tsinghua University, Beijing University of Technology, Zhejiang university, Shandong University, Xi’an Jiaotong University, Nanjing University of Science and Technology, Taiyuan University of Science and Technology, Harbin Institute of Technology, Xiamen University, Fuzhou university, The Southwest Research & Design Institute of the Chemical Industry etc) are all cooperate manufacturers research and develop honeycomb catalyst.

At present, the main raw material of catalyst is Titanium Dioxide TiO and other additives, the specification usually is cross section 150mx150mm, long 1000mm~1500mm, honeycomb hole usually is square(hole size and quantity is various) , samples as below Chart 1,

SCR catalyst samplesChart 1 SCR honeycomb denitrification catalyst

SCR device working consist ofChart 2  honeycomb denitrification catalyst working process↑

SCR system basic chemical reaction processII.SCR honeycomb denitrification catalyst production technological process:

production process of scr catalyst2.1. Production process brief description

Honeycomb catalyst production mainly includes 10 steps:

1. Titanium Dioxide and minor ingredient selection (formula R&D)

2. High speed and uniformly mixing material

3. Use pre-extruder fully filters the wet materials.

4. Sent the filtered wet material to de-airing extruder for extrude forming

5. Automatic synchronized cutting machine is able to according to different length cutting the products

6. Use manipulator load the products to carton avoid its distortion.

7. Steam damping-drum drier

8. mesh-belt kiln

9. Fixed length cutting

10. Inspection and packing

2.2. Main production equipments

Main equipments for producing above SCR honeycomb catalyst are R-19 intensive mixer, TCIW-2T box feeder, TCJ-250 pre-extruder, WDQ-150 automatic cutting machine, TCJ-310 powerful extruder, WDYD-150 manipulator etc, other corollary equipment are:2X-30 vacuum pump, SK-240PT water temperature control system etc.

At present, Xiangtan weida electrical and machinery manufacturer co., Ltd through introduce Japan, American and German technology, combined their design advantage and its many years experience in extruding industry, after years of effort successfully developed a series of honeycomb catalyst making machines such as horizontal high strength de-airing extruder, synchronized cutting machine, rewrite the history which only vertical hydraulic extruder can extrude honeycomb catalyst, improve productivity largely compare to vertical extruder is discontinuous production.

Xiangtan weida electrical and machinery manufacturer co., Ltd specialized in ceramic machinery design and manufacturer, have 30 years design and manufacture experience. At the same time, the company cooperates with domestic famous university and institute for technology discussion and exchange, joint research and development, its production technology is leading in the world.

2.3 .Machinery list and quotation of Yearly output 3000m3 SCR honeycomb catalyst




Unit price



Powder batching system
deionizer water device


1 set

deionizer water device tank


2 pcs

hold-up vessel


2 pcs

Dissolve vessel


1 pcs

hold-up vessel


1 pcs

Liquid metering pump


5 Sets

Liquid metering pump


1 sets

Liquid metering pump


2 sets

Pneumatic actuator valve

24 pcs

Stainless steel 304 Pipe
Stainless steel 304 bend
Intensive mixer


4 sets

Cooling fan


4 sets

Smoke exhaust fan


1 sets

bag dust collectorcartridge-type dust collector


1 sets

Intensive mixer control system

1 set

Intensive mixer steel platform
Box feeder


1 set



1 set



1 set

Automatic cutting machine


1 set

In pre-extrude section
Powerful de-airing extruder


1 set

Automatic cutting machine


1 set

Vertical sawing machine


1 set



1 set

Belt conveyor

3 set

Temperature controller


2 set

Vacuum pump



Temperature/pressure sensor

1 set



1 set

Simple mould clean machine

1 set

Cursing system

1 set

Air compression system

1 set

Control cable
Installation charge


2.4 Main technical parameters of Yearly output 3000m3 SCR honeycomb catalyst

Raw material preparation chart

SCR catalyst batching systemRaw material batching flow description (Raw material take 5 kinds of powder for example : A、B、C、D、E; fluid based on 4 kinds: a、b、c、d  )

1.Powder batching:

a)Storage 5 kinds powders A、B、C、D、E to powder silo A、B、C、D、E respectively;

b)According to batching ration sent the powders 将A、B、C、D、E to dosing tank per screw feeding system.

c)Open pneumatic discharge valve of dosing tank, input proportioned powder to intensive mixer once.

d)Open “mixer”, make the powders mixing 5~10 min in dry condition (mixing time is able to setup according to technique).

2. Fluid batching :

a)Storage 4 kinds powders A、B、C、D to powder silo A、B、C、D respectively

b)According to batching ration sent the fluid a、b、c、d to fluid mixer per flow controller.

c) Open fluid mixer to mix the fluid uniformly.

d)Open“fluid pump”, according to pre-set flow uniformly spray the mixed fluid to intensive mixer per fluid pipes, make the powders mixing 5~6 hours with powders (mixing time is able to setup according to technique).

e) Open discharge hole, sent the mixed material to next process.


III.SCR honeycomb denitrification catalyst machinery description:

1. CX-0.5T/H reverse osmosis +Mixed bed high-pure water equipment








Raw water booster pump


Stainless steel




Multi-media Filter


glass reinforced plastic

1 set

Liner PE


Quartz sand

4-60 mesh


High quality


Active carbon filter


glass reinforced plastic


Liner PE



Active carbon Shell


High quality


Cell filter




Include 5μprecision core filter


Reverse osmosis membrane





high pressure pump


Stainless steel




RO automatic washing system



Full set

Include washing antiseptic box


High and low voltage protection

Full set

Include touch operation panel(PLC operation system)


Main frame system

Full set


Electrical system


Middle water tank




include liquid level control system


Pure water pump


Stainless steel




Coarse Mixed bed system


glass reinforced plastic


special and transparent


anion resins macromolecule



cation resins macromolecule



regenerative system

Full set

Include regeneration; antiseptic box


Φ1130 Middle water tank




include liquid level control system


Pure water pump


Stainless steel




Pipe valve system(flow meter、pressure gauge)


Full set


conductivity/ resistivity doctor  CM-230/DZG-303


Online display and test

High pure water equipment2. Liquid conveyor system

2.1 Hold-up vessel and Dissolve vessel (6 pcs): Include deionizer water, ammonia water hold-up vessel.

2.2 metering pump (8 set):include deionizer water, ammonia water metering pump etc.

2.3 pneumatic ball valve (24pcs): include reversing solenoid valve, MONITORING SWITCH

2.4 Others: Pipe arrangement (according actual site arrangement)

3. D type vertical intensive mixer



▲vertical intensive mixer main technical parameters:

●  Effective volume: ф2080×610(2000L)

●  Main shaft rotation speed: 750RPM(Maximum) adjustable

●  Rotary speed: 8~9 RPM

●  Total power: 139KW

●  Mixing period: 960 (adjustable)

●  Overall size: 3700×2500×2640mm

●  Weight: around 7000kg

▲Main components introduction:

●  Material introduction: Machine frame is high quality Carbon Construction Steel Q235A and 20# steel, Overall welding structure, All parts in touch with raw materials are made of acidproof alkali stainless steel 316L.

●  Main purchased parts: Motor is domestic brand (Xiangtan)

Reducer: material harrower drive is SEW

Rotating plate drive is TX

● Electronic control introduction: Fully automatic control include material feeding, mixing, and discharge

●PLC adopt SIEMENS or Mitsubishi

T35-11No.4A Cooling Fan

Used for intensive mixer


air volume:3849m3/h

Wind pressure:88Pa

Rotating speed:1450r/min

The transmission medium of fan is microcorrosion acid saturated damp air, temperature is 95℃, Fan bearing adopt NSK, blade, shield and bearing block adopt stainless steel 304.


GD30K2-12No.5C ventilation fan

Used for intensive mixer


Air volume:8000m3/h

Wind pressure:200Pa

Rotating speed:1800r/min

The transmission medium of fan is microcorrosion acid saturated damp air, temperature is 95℃, Fan bearing adopt NSK, blade, shield and bearing block adopt stainless steel 304.


DF03-R cartridge-type dust collector

Air volume:Q=1500 m3/h

filter area::30 m2(cartridge qty:3pcs)

cartridge size:Φ350×660 mm

Cartridge material: filter media is high quality PET + PTFE coating

Filter efficiency: 99.99%

Filter wind speed: V=0.833 m/min

Dust collector Emptying concentration: 20-50 mg/ m3

Cartridge temperature resistance: <100℃

Dust cleaning type: pulse cleaning

Computation of air compression (customer prepared): 0.3-0.5 m3/min

Air compression pressure: 0.45-0.5 Mpa

Discharge type: Φ150 mm electronic discharge valve (stainless steel 304)

Supporting centrifugal fan: 9-19 NO 4A

Air volume:1410-1704 m3/h

Wind pressure:3507-3253 Pa

Motor poser:3 KW

4. TCIW-2T Automatic box feeder

box-feeder for scr catalyst productionMain technical parameters:


● All parts in touch with raw materials are made of stainless steel 304

● Hopper adopts stainless steel 304 (4mm), effective volume is 1.5m3.

▲ Technical requirements

●Y 90S-4  1.1KW  1400r/min

Driving motor of belt conveyor: Y 90S-4  1.1KW  1400r/min

●  Reducer of belt conveyor: Cycloid reducer, NBWED 42

●  Driving motor of feeding part: Y 132S-4  5.5KW  1440r/min

●  Reducer of belt conveyor: Cycloid reducer, NBWY 27

●  Belt conveyor: PVC material

●  Electric control system: vertical type(include wiring between operation table to machine )

●  Overall size(L×W×H):约3500×1360×2890mm

●  Power resource:380V  three phase  50HZ

5.TCJ-250 Pre-extruder

pre-extruder for scr catalyst production

pre-extruder of scr catalyst production-drawing

▲Technical requirement:

●  All parts in touch with raw materials are made of stainless steel 304

▲  Up part:

●  Driving motor: Y200L2-6  22KW  970r/min

●  Reducer: Cycloid reducer XWD9-35-22-6P

●  Frequency converter: INVT

●  Screw blade: Φ250mm  304 stainless steel

●  Material cylinder: inner wall adopt stainless steel 304

●  Rotating speed of extruding shaft: 25RPM (adjustable)

▲  Down part:

●  Driving motor: Y200L2-6  22KW  970r/min

●  Reducer: Cycloid reducer XWD9-35-22-6P

●  Frequency converter: INVT

●  Screw blade: Φ250mm, 304 stainless steel

●  Extruding shaft: 40Cr

●  Extruding cylinder: inner wall adopt stainless steel 304 with cooling water jacket.

●  Rotating speed: 25RPM

●  Extruding speed: 1.5~2.5T/H (adjustable)

●  Overall size(L×W×H): 6000×1130×2088 mm

●  Net weight: 6000kg

6. TCJ-310 high strength de-airing extruder

310-de-airing-extruder for scr catalyst production▲Technical requirements:

●All parts in touch with raw materials are made of stainless steel 304

▲Up part:

●  Driving motor: SEW, DFV225S4/V 37KW 1470r/min

●  Up shaft reducer: SEW, MC3PLSF05 1:55.7403

●  UP shaft screw blade: Φ180mm, stainless steel, inner shaft water cooling

●  Up material cylinder: inner wall adopt stainless steel with water cooling system

●   Rotation speed of up extruding shaft: 29.6RPM (adjustable)

●  Cutter: adopt stainless steel 304

▲  Down part:

●  Driving motor of down shat: SEW, DFV280S4/V 75KW 1480r/min

●  Reducer of down shaft: SEW, M3PSF60 1:86.5623

●  Main screw blade: Φ310,stainless steel 304,inner shaft water cooling

●  Supporting screw blade: Φ220 stainless steel, inner shaft water cooling

●  Main shaft material: 40Cr

●  Extruding cylinder: stainless steel with water cooling jacket

●  Temperature and pressure sensor on extruding end, they convert signal and feedback to control plate.

▲  De-airing room

●  Inner wall: stainless steel 304

●  Vacuum pump: >550 liter/min

●  Motor for de-airing room: 3Kw

●  When vacuum pump working, noise should less than 75dB(within 1M), vacuum pump capacity should make negative pressure in vacuum room meet -0.096MPa.

●  Reserve observation window on 4 sides of vacuum room

●  Control cabinet: vertical type (include wiring between cabinet with machine)

●  Cooling pipe: exposed part with thermal insulation jacket

●  Power supply: 380V three phase 50HZ

●  Over all size(L×W×H): 6650×1730×2200 mm

●  Net weight: 12000 Kg

7. WDQ-150 Auto cutting machine


8. WDPY-150 Manipulator

manipulator for scr catalyst production▲ The function of manipulator:

The manipulator is placed after automatic cutting machine and Conveying positioning system, its main function is load the honeycomb adobe to tray, the process include clamping, lift, translational motion, put down, take off, lift, translational motion and put down.

●  Frame: welding components

●  Motor power: YEJ-80M24 0.75KW 1405r/min

●  Reducer: RV63 1:25

●  Up and down guide rail and air cylinder

●  Clamp and open guide rail and air cylinder

●  Sponge plywood

●  Electrical control system

●  Max. grabbing weight: 30kg

●  Max. lifting distance: 100mm

●  Max. displacement distance:1500mm

●  Every meters of cycle time: 15s/time

●Overall size:2900×1800×2600mm

●Net weight:450 Kg

9. Automatic cutting machineFinished product fixed length cutting

finished-catalyst-cutting-machine▲Main technical parameters:

Max cutting length:350mm        Max cutting height:240mm

Cutting bed size:440×490mm       Blade length:2900mm

Blade width:3-13mm

Angle of Inclination of working  platform:Back and forth 10º

Angle of Inclination of working  platform:Right and left 15º

Main motor power:1HP

Gear box motor power:1HP

Gear box speed regulating:Total 4 gears: 30、50、80、130

Welding capacity:3-13m/m

Weight: 280Kg

Overall size(LxWxH):920×700×1720mm

SCR honeycomb catalyst