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汽车尾气三效催化剂性能试验方法
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GBT 34248-2017
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标准编号: GB/T 34248-2017 (GB/T34248-2017)
中文名称: 汽车尾气三效催化剂性能试验方法
英文名称: Performance test method of three-way catalyst
行业: 国家标准 (推荐)
中标分类: G74
国际标准分类: 71.100.99
字数估计: 10,147
发布日期: 2017-09-07
实施日期: 2018-04-01
起草单位: 福州大学化肥催化剂国家工程研究中心、南化集团研究院、山东省产品质量检验研究院
归口单位: 全国化学标准化技术委员会化工催化剂分技术委员会(SAC/TC 63/SC 10)
提出机构: 中国石油和化学工业联合会
发布机构: 中华人民共和国国家质量监督检验检疫总局、中国国家标准化管理委员会
GB/T 34248-2017: 汽车尾气三效催化剂性能试验方法
GB/T 34248-2017 英文名称: Performance test method of three-way catalyst
ICS 71.100.99
G74
中华人民共和国国家标准
2017-09-07发布
2018-04-01实施
中华人民共和国国家质量监督检验检疫总局
中国国家标准化管理委员会发布
前言
本标准按照GB/T 1.1-2009给出的规则起草。
本标准由中国石油和化学工业联合会提出。
本标准由全国化学标准化技术委员会化工催化剂分技术委员会(SAC/TC63/SC10)归口。
本标准起草单位:福州大学化肥催化剂国家工程研究中心、南化集团研究院、山东省产品质量检验研究院。
本标准主要起草人:肖益鸿、郑勇、蔡国辉、翟中华、邱爱玲、陈延浩、邹惠玲。
汽车尾气三效催化剂性能试验方法
1 范围
本标准规定了汽油车三效催化剂起燃温度、空燃比及储氧量的试验方法。
本标准适用于以堇青石蜂窝陶瓷或金属蜂窝作为基体,并负载催化剂涂层的汽油车尾气净化三效催化剂。
2 规范性引用文件
下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件,仅注日期的版本适用于本文
件。凡是不注日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。
GB 18352.5-2013 轻型汽车污染物排放限值及测量方法(中国第五阶段)
3 术语和定义
下列术语和定义适用于本文件。
3.1
三效催化剂
在理论空燃比14.63或氧过量系数1附近能同时氧化一氧化碳、碳氢化合物和还原氮氧化物的催化剂。
3.2
起燃温度
对某一污染物的催化转化率达到50%时所对应的催化剂入口温度。用符号T50(i)表示。
3.3
空燃比 可燃混合气中空气质量与燃油质量的比值。
3.4
氧过量系数 反应气氛的计算空燃比与汽油的理论空燃比14.63的比值。
3.5
转化率 在一定的条件下,催化剂进出口一氧化碳、碳氢化物或氮氧化物)体积分数的变化百分数。
3.6
转化温度 催化剂对某一污染物的催化转化效率达到一定值时所对应的催化剂入口温度。
4 原理
气体中的一氧化碳、碳氢化物和氮氧化物等有害气体,在催化剂的作用下,发生氧化还原反应生成二氧
化碳、水和氮气。通过测定反应前后气体中的一氧化碳、碳氢化物和氮氧化物的体积分数,计算出催化
剂的起燃温度、储氧量和空燃比特性,以此来表征催化剂的性能。
5 试验装置
5.1 流程
汽车尾气三效净化催化剂性能试验装置示意图见图1。
5.2 仪器设备
5.2.1 质量流量计:准确度±2%F.S.,线性±1%F.S.,重复精度±0.2%F.S.,绝对测量误差不大于5%。
5.2.2 注射泵:误差不大于±0.5%。
5.2.3 尾气分析仪:按GB 18352.5-2013附录CD中CD.1.3、CD.2、CD.3的规定。
5.2.4 反应器:内径30mm;额定温度1000℃,功率应满足最高升温速率30℃/min,温度控制精度
±2℃;恒温区不小于10cm;反应温度取催化剂气体进口方向离催化剂床层轴心2cm处温度,温度测
量精度低于1.5℃。
5.2.5 系统控制及采样记录系统:数据采集系统对温度、污染物浓度的采样频率不小于1Hz。
5.3 校验及允许差
正常情况下,试验装置的平行性、复现性每个月用基准样至少测定1次。特殊情况下,可随时校验。
同一基准样品进行至少3次的重复测试,其起燃温度复现性(极差值)不大于10℃,储氧量复现值
(相对值)在±5%以内。
6 试验步骤
警示---本标准所涉及的试验用原料气和尾气对人体健康和安全具有中毒、易燃、易爆危害,必须
严防系统漏气,现场严禁有明火,并且应配有必要的灭火器材和排风设备等预防设施。
6.1 试样的制备
试样规格为ϕ25mm×50mm,试样应保持结构完整且无明显外观缺陷和裂纹。
6.2 试样的装填
在试样的两端缠绕耐高温陶瓷纤维棉后,装入反应器,将催化剂两端空隙处用陶瓷纤维棉密封严
实,并接入系统。
6.3 系统试漏
向系统内缓慢通入空气,在压力不低于0.1MPa条件下,保持10min后,用涂刷中性发泡剂等方法
检查所有密封点,如有泄漏应进行处理。试漏合格后,打开排气,使系统降至常压。将进口段测温热电
偶插入热电偶套管内,使其热端位于气体入口催化剂床层内2cm处。
6.4 活化
将反应器以10℃/min的速率升至催化剂入口温度稳定于150℃后,向系统通入混合气(其组分见
6.5 起燃温度、空燃比特性及储氧量的测定
6.5.1 起燃温度
将反应器以10℃/min的速率升至催化剂入口温度稳定于150℃时,通入混合气(见表1,λ=
0.998),空速为60000h-1,系统压力为常压。继续以10℃/min的速率升温直至催化剂入口温度大于
或等于500℃,并实时记录反应器在150℃~500℃温度范围内反应器进、出口的一氧化碳(CO)、碳氢
化物或氮氧化物值,并计算其转化率。
以入口温度为横坐标,转化率为纵坐标绘制起燃温度特性曲线。
按照直线插值法分别求出催化剂试样对一氧化碳、碳氢化物或氮氧化物的转化温度(T50,T90)。
将反应器以10℃/min的速率升温至催化剂入口温度稳定于450℃时,通入氧过量系数(λ)从
0.940到1.060的混合气(见表1),空速为60000h-1,系统压力为常压。实时测量催化剂进、出口的一
氧化碳、碳氢化物或氮氧化物值,测试点不少于10个。
以氧过量系数为横坐标,转化率为纵坐标绘制空燃比曲线。
求出样品在氧过量系数(λ=0.998)时对一氧化碳、碳氢化物或氮氧化物的转化率。
6.5.3 储氧量
将反应器以10℃/min的速率升温至催化剂入口温度稳定于450℃时,通入氧过量系数为0.940
的混合气,保持一定时间(t1)(不少于5s)后,瞬间将反应气氛切换为氧过量系数为1.060的混合气 (见
图2)。通过空燃比仪或者废气分析仪测量催化剂的λ值,得到样品λ信号突变至λ=1的时间t2。重
测试完毕。取连续5次测定结果的算术平均值作为测定结果。
7 试验数据处理
7.1 转化率
转化率以E 计,按式(1)计算:
7.2 储氧量
储氧量,数值以毫克(mg)表示,按式(2)计算:
GB/T 34248-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.99
G 74
Performance Test Method of Three-way Catalyst
ISSUED ON. SEPTEMBER 7, 2017
IMPLEMENTED ON. APRIL 1, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of
China.
3. No action is required - Full-copy of this standard will be automatically &
immediately delivered to your EMAIL address in 0~60 minutes.
Table of Contents
Foreword ... 3
1 Application Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Principle ... 5
5 Test Apparatus ... 5
6 Test Procedures ... 7
7 Test Data Processing ... 9
Annex A (Normative) Airspeed Correction of Reaction Mixed Gas ... 11
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard was proposed by China Petroleum and Chemical Industry Federation.
This Standard shall be under the jurisdiction of Subcommittee 10 on Catalysts of
National Technical Committee 63 of Standardization Administration of China.
The main drafting organizations of this Standard. Fuzhou University State Engineering
Research Institute of Fertilizer Catalysts, Research Institute of Nanjing Chemical
Industry Group, Shandong Institute for Product Quality Inspection.
The main drafters of this Standard. Xiao Yihong, Zheng Yong, Cai Guohui, Zhai
Zhonghua, Qiu Ailing, Chen Yanhao, Zou Huiling.
Performance Test Method of Three-way Catalyst
1 Application Scope
This Standard specifies the test method of light-off temperature, air-fuel ratio and
oxygen storage capacity of three-way catalyst for gasoline vehicles.
This Standard applies to the three-way catalyst for the purification of the tail gas of
vehicles, which is made by using cordierite honeycomb ceramics or metallic
honeycombs as base and loading catalyst coating.
2 Normative References
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition dated applies to this document. For
undated references, the latest edition of the referenced documents (including all
amendments) applies to This Standard.
GB 18352.5-2013, Limits and Measurements Methods for Emissions from Light-
duty Vehicles (China 5)
3 Terms and Definitions
For the purposes of this Standard, the following terms and definitions apply.
3.1
three-way catalyst
A catalyst which is capable of oxidizing carbon monoxide, hydrocarbons and reduced
nitrogen oxides at the same time, near the theoretical air-fuel ratio 14.63 or oxidizing-
to-reducing components ratio 1.
3.2
light-off temperature
The temperature of catalyst inlet corresponding to the conversion of some pollutant up
to 50%. It is expressed with the symbol T50(i).
NOTE “i” represents pollutants carbon monoxide (CO), hydrocarbons (HC) and
nitrogen oxides (NOx).
3.3
5.2.4 Reactor. inner diameter 30 mm; rated temperature 1 000°C, power meeting the
maximum temperature rise rate 30°C/min, temperature control accuracy ± 2°C;
constant-temperature zone not less than 10 cm; reaction temperature as the
temperature of 2 cm from the axis of catalytic bed in the catalyst gas inlet direction,
temperature measurement accuracy not lower than 1.5°C.
5.2.5 System control and sampling recording system. the sampling frequency of the
data acquisition system for temperature and pollutant concentration shall not be less
5.3 Verification and tolerances
Under normal conditions, the parallelism and reproducibility of the test apparatus shall
be determined once each month at least using reference specimens. Under special
circumstances, they may be verified at any time.
One reference specimen shall be used for three repeated tests at least; the
reproducibility of the light-off temperature (maximum difference value) is not greater
than 10°C; and the reproducibility of oxygen storage capacity (relative value) is within
± 5%.
6 Test Procedures
pose toxic, combustible and explosive hazards to the health and safety of human
body, so air leakage of the system shall be prevented, no open fire is allowed on
site, and necessary fire-fighting equipment and ventilation equipment and other
protective facilities shall be provided.
6.1 Preparation of specimens
The dimensions of specimens are ϕ 25 mm × 50 mm; and the specimens shall be
maintained for structural integrity and free from visible defects and cracks.
6.2 Filling of specimens
After wrapping high temperature resistant ceramic fibre cotton at both ends of the
ends of catalyst, and connect to the system.
6.3 System leak test
Pump air into the system, maintain for 10 min under the condition of pressure not lower
than 0.1 MPa, use the methods including brushing neutral foaming agent to check all
sealing points, and deal with it in case of any leak. After the test result is approved,
open the system to ventilate to reduce the pressure of the system to normal pressure.
Insert the temperature measurement thermocouples for the inlet into the thermowell,
of the catalyst specimens for carbon monoxide (CO), hydrocarbons (HC) or nitrogen
oxides (NOx).
Raise the temperature of the reactor at 10°C/min until the catalyst inlet temperature
becomes stabilized at 450°C, pump mixed gas of oxidizing-to-reducing components
ratio (λ) 0.940 ~ 1.060 (see Table 1), and maintain the airspeed at 60 000 h-1 and the
system pressure at normal pressure. Measure in real time the values of carbon
monoxide (CO), hydrocarbons (HC) or nitrogen oxides (NOx) at the inlet and outlet of
catalyst. The test points shall not be less than 10.
Use the oxidizing-to-reducing components ratio as abscissa and the conversion as
ordinate to plot the air-to-fuel curve.
Calculate the conversion of the specimens for carbon monoxide (CO), hydrocarbons
0.998.
6.5.3 Oxygen storage capacity
Raise the temperature of the reactor at 10°C/min until the catalyst inlet temperature
becomes stabilized at 450°C, pump mixed gas of oxidizing-to-reducing components
ratio (λ) 0.940, and maintain for a certain time (t1) (not less than 5 s) before switching
the reaction atmosphere instantly to mixed gas of oxidizing-to-reducing components
ratio 1.060 (see Figure 2). Measure the λ value of catalyst using air-to-fuel ratio meter
or exhaust gas analyzer and obtain the time t2 of the specimens’ λ signal changing
suddenly to λ = 1. Repeat the test for 5 times. When the 5 consecutive test results
results is not greater than 5%, the oxygen storage capacity test is completed. Take the
arithmetic mean value of the 5 consecutive test results as the test result.
7 Test Data Processing
7.1 Conversion
The conversion is calculated in terms of E in accordance with Formula (1).
where,
φi1—the volume by volume concentration of the gas pollutant i at the catalyst inlet,
expressed in %;
φi2—the volume by volume concentration of the gas pollutant i at the catalyst outlet,
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