CN102614942A

CN102614942A - Automobile tail gas three-way catalyst drying technology

Info

Publication number: CN102614942A
Application number: CN2012100473434A
Authority: CN
Inventors: 翁希明; 纪成绸; 翁夏翔; 薛若洋; 纪家禧
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-02-27
Filing date: 2012-02-27
Publication date: 2012-08-01

Abstract

The invention discloses an automobile tail gas three-way catalyst drying technology. In the process, cordierite is porous cordierite with pores inside; catalyst slurry is applied on the surfaces of the pores in the cordierite; the catalyst slurry comprises composite aluminum oxide, a cerium zirconium oxygen storage material and active metal palladium or rhodium; the solvent of the catalyst slurry is water; and the automobile tail gas three-way catalyst is placed under the microwave environment of 2,400 to 2,500 MHz and dried until the water content is less than 7 percent. By adoption of the technical scheme, microwaves directly act on water molecules to cause vibration of the water molecules and the vibration is converted into heat energy, so that the heating and drying aim is fulfilled. By adoption of the technology, microwave heating is high in speed, the production efficiency is high, the work environment is good, energy is saved and consumption is reduced, and the catalytic performance of the catalyst is improved.

Description

A kind of ternary catalyst for automobile tail gas drying technology

Technical field

The present invention relates to a kind of catalyst drying technology, relate in particular to a kind of ternary catalyst for automobile tail gas drying technology.

Background technology

Be used for catalyst such as vehicle exhaust processing at present; Mostly be attached on the cellular ceramic substrate; For making catalyst evenly attached to the surface of porous carrier, how catalyst is added water furnishing pulpous state, soak into carrier hole surface; Then will be with the carrier oven dry of catalyst pulp, preparation porous carrier catalyst prod.

The technology conventional methods that adopt are dried more at present, for example: and steam drying, electrothermal drying, heated-air drying etc., adopt said method to have following defective:

Drying time is long: taken off to below 10% by the 30%-20% water content; Adopt said method to need more than 22 hours usually; The long production cycle also brings the risk aggravation of burst factor in the production process, for example has a power failure in the production process etc., causes scrapping of entire block easily.

Product easy of crack, variable color: adopt conventional furnace drying method, easy to change, the cracking of material table face influences product quality and quality.

The product catalytic performance is general.

Production environment is abominable, and equipment takes up an area of big, and the heating heat dissipation capacity is big, and dust is many, and noise is big, and labor strength is big, and the product waste heat amount after the oven dry is big, and the workman operates inconvenience, more exists to scald risk.

Productivity ratio is low, and conventional method is taked the batch (-type) batch production, and production efficiency is low, and batch between otherness big.

Summary of the invention

The object of the invention is to provide the ternary catalyst for automobile tail gas stoving process of a kind of efficient stable and production excellent product performance.

For realizing the foregoing invention purpose, the technical scheme that the present invention takes is following: a kind of ternary catalyst for automobile tail gas stoving process, it is characterized in that,

With catalyst pulp on the surface applied of said carrier inside hole; Said carrier is inner porous cordierite with hole; Contain water, composite alumina, cerium zirconium hydrogen-storing material, reactive metal palladium or rhodium in the said catalyst pulp, again with said be coated with the carrier that applies catalyst pulp place dry under 2400～2500MHz microwave environment to the weight water content less than 7%.

Wherein, pass through a plurality of microwave devices successively with being coated with the carrier that applies catalyst pulp.

Wherein, said microwave device quantity is 42, and each is coated with the carrier heat time heating time in each microwave device that applies catalyst pulp is 15s.Adopt technical scheme of the present invention,, cause the hydrone vibration, be converted into heat energy, and then reach the purpose of heating, drying because microwave directly acts on hydrone.Use heating using microwave according to the invention not only to heat soon, production efficiency is high, and good work environment is energy-saving and cost-reducing, and to the catalytic performance of catalyst increase (seeing specific embodiment part for details).

The specific embodiment

Further specify technical scheme of the present invention and technique effect according to heating using microwave and conventional heat oven dry contrast test below:

Present embodiment relates to the specification and the performance parameter of equipment:

Separate unit micro-wave oven peak power output: 42KW

Microwave frequency: 2450 ± 50MHz

Microwave wavelength: 125.00-120.00mm

Experimental condition

Catalyst: will contain composite alumina, cerium zirconium hydrogen-storing material, reactive metal palladium or rhodium, catalysis material and water be made into paste liquid, be coated on the internal pore surface of porous cordierite ceramics, take following mode to dry then respectively.

Test one: oven dry

Microwave drying technology: the carrier that evenly distributed being coated with applies catalyst pulp is delivered on the evenly distributed microwave device through conveyer belt and is dried, and every group of microwave opened 38s, always opens microwave 494s.

Drying baker stoving process: carrier is put into drying baker, constant temperature 80 degree constant temperature 120 degree 1140 minutes again after 180 minutes, promptly 22 hours.The result relatively

A. microwave drying test

Table 1

B. drying baker test

Table 2

Dehydration rate=(weight after former weight-oven dry)/former weight wherein

The measurement of residual moisture is with the material metage after the oven dry, places then under 110 ℃ of temperature and dries to constant weight, calculates with formula:

Weight after residual moisture=(weight after the weight-constant weight after the oven dry)/oven dry.

Draw by above data:

1. carrier microwave oven dry average dehydration is 14.0%, and carrier drying baker oven dry average dehydration is 15.3%;

2. the carrier microwave drying and dewatering is more even; This point can be worth from square margin, so carrier drying baker drying and dewatering fluctuates more greatly

Drying time and efficient compare:

Item compared	Microwave technology	Drying baker technology
			Per 8 hours oven dry carrier numbers	360	108
Per 8 hours power consumption general powers	43.89KW·h	23KW·h
			Each carrier power consumption	0.12KW·h	0.21KW·h
Every kilowatt hour amount vector	8.2 it is individual/KWh	4.7 it is individual/KWh

Table 3

Draw from data analysis: microwave drying technology than drying baker power consumption lack, efficient is high.

Experiment two: oven dry back material performance contrast experiment

For eliminate accidental error as far as possible, this experiment specimen in use is taken from drying baker oven dry material and microwave drying process stream in the experiment one, and sampling is made as follows:

Sample 1: get nine finished products of drying baker experiment in the experiment one, as 1 group in sample;

Sample 2: get nine finished products of microwave drying experiment in the experiment one, as 2 groups in sample;

With 2 groups in 1 group in sample and sample roast 15 hours under 700 ℃ of temperature, in every group of 9 samples, get 5 then at random and process fresh appearance, process aging appearance and carry out Performance Detection for remaining 4.Two groups of samples using identical check criteria and method.

Fresh appearance is meant the sample that sampling observation product appearance obtains after 1 hour through 450 ℃ of roasts; Aging appearance is meant the sampling observation product appearance sample that roasting obtained in 20 hours in 960 ℃ of air.

Fresh appearance is corresponding to the catalytic performance of new product, the catalysis situation that aging original mold is intended is catalyst behind 00,000 kilometers of application 1s on the automotive exhaust catalysis.

Table 4 be 1 group with each item test index of 2 groups, for ease of relatively, numerical value has been calculated as mean value in the form.(a certain digital average value of for example fresh appearance is that every group of each fresh this result value of appearance adds up divided by 5, and a certain digital average value of aging appearance is that every group of each aging this result value of appearance adds up divided by 4)

1 group in sample and 2 groups of performance indications of sample

Table 4

The light off characteristics of vehicle tail gas triple effect catalyst is meant that under theoretical air-fuel ratio, catalyst reaches 50% o'clock reaction temperature to the conversion ratio of CO, HC and NOx, i.e. the initiation temperature of catalyst and ignition state.Its method of inspection is under fixing gas source condition, firm discharge, and since 150 ℃ or 200 ℃, the 50 ℃ of conversion ratios that detect catalyst to CO, HC and NOx in every interval reach 95% detection of end when above up to conversion ratio.With the temperature is abscissa, and conversion ratio is that ordinate is made CO, HC and NOx conversion ratio---the activity curve figure of temperature, the conversion ratio of on figure, finding out three kinds of pollutants are the initiation temperature that 50% o'clock reaction temperature is each pollutant.(explain: catalyst light off characteristics T _50%The test result temperature low more and three temperature are more on average good more, its ignition is fast more, performance is good more.)

The triple effect property of catalyst is meant under theoretical air-fuel ratio condition; Same temperature spot catalyst is to the clean-up effect of three kinds of pollutants; Be its conversion ratio, general temperature spot is chosen as catalyst lower limit serviceability temperature in normal working conditions, and fresh appearance is selected in 400 ℃; Aging appearance is selected in 450 ℃, and the conversion ratio of this temperature spot can be read from above-mentioned active activity curve figure.(explain: catalyst triple effect property (400/450 ℃ of conversion ratio) conversion ratio is high more good more, explains that its performance is good more.)

The average pore volume of catalyst is meant the average internal pore volume of every gram catalyst.Its detection method is to adopt the adsorbance mensuration, promptly under liquid nitrogen temperature through detecting the certain mass catalyst calculates catalyst to the saturated extent of adsorption of liquid nitrogen pore volume.

The detection of above parameter can reflect the quality of catalyst performance basically, is the concentrated expression of catalyst performance.

We can draw from above data contrast, the catalyst behind the microwave drying, and the drying technology that performance is more traditional has tangible raising.

The above is merely embodiments of the invention; Be not so limit claim of the present invention; Every equivalent structure or equivalent flow process conversion that utilizes description of the present invention to do; Or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present invention.

Claims

1. a ternary catalyst for automobile tail gas stoving process is characterized in that,

2. ternary catalyst for automobile tail gas stoving process according to claim 1 is characterized in that, passes through a plurality of microwave devices successively with being coated with the carrier that applies catalyst pulp.

3. ternary catalyst for automobile tail gas stoving process according to claim 3 is characterized in that, said microwave device quantity is 42, and each is coated with the carrier heat time heating time in each microwave device that applies catalyst pulp is 15s.