1. 背景与简介
过去几年国内多个重点城市出现严重的雾霾天气,引发了市场对中国油品质量的广泛质疑。随着国家对环境保护的重视和民众对公共健康意识的提高,对降低车用燃油、船用和锅炉用燃油、航空煤油中的硫含量提出了更高的要求。石油产品中的多种硫化物是导致空气污染的重要因素;而在PM2.5监测中,硫化物也是一个组成部分。加强对石油产品中含硫量的严格控制,空气中PM2.5微颗粒的浓度会相应降低。
对车用燃油中硫含量控制,是减少城市空气污染的主要举措之一。国家自2011年7月1日开始实施轻型汽油车排放的国IV标准,并将于2014年1月1日在国内实施相应的国IV标号汽油。目前,北京、上海、广州等大城市已经在使用国IV标号汽油,并开始着手准备使用国V标号的汽油。国V标号的汽油硫含量小于10mg/kg。
能量色散型X射线荧光光谱仪已经被广泛的应用于石油炼化企业、产品质量监察、环境监测监察和检测公司分析实验室,做为油品中硫含量的快速分析工具
本应用方案展示了能量色散X射线荧光光谱法Compass4294测定石油产品中硫含量.结果表明,该方法不仅快速,简便,而且准确度和精密度较好.适用于测定包括石脑油,中间馏分渍,燃料油,渣油,润滑油基础油和无铅汽油在内的碳氢化合物中的硫含量.浓度范围从2ppm到5w%
2. 仪器参数
为硫分析设定了工厂优化的测试条件。客户无需标定设备即可即时现场检测样品。
该技术可实现低检测限和高精度,而无需消耗氦气,真空泵。也无需复杂而耗时的化学样品制备。只需将样品放入样品杯中,即可上机测试,整个测试过程*无损,测试时间仅需130秒,且结果准确。
3. 准确性研究
为了研究Compass 4294的准确性,对市售的含50 ppm硫的燃油参考材料进行了十次测量。
连续进行20次50 ppm的测试,测试值显示在下面的报告中。
> 50 ppm硫的测试性能
Unit:单位 | ppm | 测试时间Test Time: 130 seconds | |||||
Test Number测量次数 | Calibration Curve 标定曲线 | Sulfur (ppm) | |||||
1 | Fuel Oil汽油 | 51.64 | |||||
2 | Fuel Oil汽油 | 52.26 | |||||
3 | Fuel Oil汽油 | 48.96 | |||||
4 | Fuel Oil汽油 | 51.75 | |||||
5 | Fuel Oil汽油 | 50.29 | |||||
6 | Fuel Oil汽油 | 45.20 | |||||
7 | Fuel Oil汽油 | 49.99 | |||||
8 | Fuel Oil汽油 | 52.28 | |||||
9 | Fuel Oil汽油 | 52.99 | |||||
10 | Fuel Oil汽油 | 51.64 | |||||
11 | Fuel Oil汽油 | 50.44 | |||||
12 | Fuel Oil汽油 | 50.67 | |||||
13 | Fuel Oil汽油 | 53.48 | |||||
14 | Fuel Oil汽油 | 53.34 | |||||
15 | Fuel Oil汽油 | 54.95 | |||||
16 | Fuel Oil汽油 | 52.55 | |||||
17 | Fuel Oil汽油 | 53.65 | |||||
18 | Fuel Oil汽油 | 51.94 | |||||
19 | Fuel Oil汽油 | 53.00 | |||||
20 | Fuel Oil汽油 | 51.45 | |||||
Certified Standard Sulfur Value标准值 | 50.00 ppm | ||||||
Average Test Sulfur Value by Compass4294 测试值 | 51.62 ppm |
4. 精密度研究
为了研究Compass 4294的精度,分析了两个含硫量分别为0.1%和1%的标准原油样品。下面显示的结果表明,指南针4294可对各种石油样品进行精确测量。
XRF设备的另一个重要参数是分析的可重复性。
> 0.1%和1%硫的测试性能
Unit:单位 | % | 测量时间Test Time: 130 seconds | |
No. | Calibration Curve标定曲线 | Sulfur | Sulfur |
1 | Crude Oil原油 | 0.106 | 1.071 |
2 | Crude Oil原油 | 0.106 | 1.083 |
3 | Crude Oil原油 | 0.108 | 1.078 |
4 | Crude Oil原油 | 0.106 | 1.074 |
5 | Crude Oil原油 | 0.104 | 1.061 |
Certified Standard Sulfur Value(%)标准值 | 0.100 | 1.000 | |
Test Sulfur Value by Compass4294(%)测试值 | 0.106 | 1.073 | |
Sn (Standard Deviation)标准偏差 | 0.001 | 0.008 | |
Error (%)误差 | 0.006 | 0.073 | |
RSD (Relevant standard deviation) 相对标准偏差 | 1.33% | 0.77% |
5.测试程序和校准演示
一系列进口石油标准品已在工厂用于标定EDXRF荧光光谱仪Compass4294。客户可以运行样品测试,而无需在现场进行任何进一步的校准过程。
只需执行四个步骤即可进行测量。如下图所示,了解如何准备和放置样品进行分析的图片
1-1,准备样品杯。用6 um聚酯薄膜薄膜在分析侧将样品杯盖好。在保护测试窗口平台上还预先设置了相同的聚酯薄膜,以避免任何意外样品泄漏到分析仪中。
1-2,通常将来自每种标准品的3-5毫升油倒入分析仪的杯子中直至加注线。
1-3,将样品杯放在指南针XRF样品装载器上,它*适合样品杯尺寸。
1-4,单击“开始"按钮以运行分析。结果将在130秒后显示。
使用一组已知硫浓度的市售重质燃油标准品来进行校准。
下面的图2-2显示了百分比水平下高浓度范围的油中硫的相关曲线。
用线性函数近似该数据。 R2是确定系数。理想的相关性的R2值为1。
5. 结论
本应用案例介绍了一种新型分析仪表Compass4294 ---X射线荧光光谱仪在原油及汽车用油中硫量监测的应用。它是基于能量色散 X 射线荧光光谱的测量原理,进行原油中硫含量测定的,与传统色谱法相比,在实际应用中具有简便、准确、快捷的特点
用能量色散X射线荧光光谱仪Compass4294代替传统的灯硫法 (GB/T380 - 88)和管硫法 (GB/T387- 90 )测定石油产品硫含量 ,取得了与传统方法相一致的分析准确性和重复性.该方法具有快速,经济等优点 ,是一种比较理想的测定石油产品中硫含量的光谱仪
Sulfur-in-oil Analyzer Compass 4294 Application Note- Sulfur
1. Background and Introduction
Fuels & oils monitoring- Compass 4294 XRF
For ships operating outside designated Emission Control Areas, IMO has set a limit for sulphur in fuel oil used on board ships of 0.50% m/m (mass by mass) from 1 January 2020. This will significantly reduce the amount of sulphur oxide emanating from ships and should have major health and environmental benefits for the world, particularly for populations living close to ports and coasts.
Since 1 January 2015, the sulphur limit for fuel oil used by ships operating in Emission Control Areas (ECAs) designated by IMO for the control of sulphur oxides (SOX) has been 0.10% m/m.
The powerful Energy Dispersive X-ray Fluorescence (EDXRF) Compass 4294 serial Sulfur analyzer of ESI Instrument are capable of more sensitive and precise analysis than can be expected from a laboratory class analyzer. This application note demonstrate the Compass 4294 test performance of sulfur in different oil and fuel samples.
2. Instrument parameter
Factory optimized test conditions are set for sulfur analysis. This industry leading
technology enabling low detection limits and high precision without the need for consumable helium gas, a vacuum pump, or extensive sample preparation.
4. Test procedure and Calibration demonstration
A serial of commercial available oil standards were used to calibrate the EDXRF spectrometer at factory. Customer can run the sample test without any further calibration process on-site.
Only four steps are needed to make the measurement. See pictures of how to prepare and put the sample for analysis as below picture
1-1, Prepare the sample cup. The cup was closed on the analytical side with a 6 um thin Mylar film. The same Mylar was also preset on the protection test window platform to avoid any accident sample leak into the analyzer.
1-2, Typically 3-5 ml oil from each standard was poured into the analyzer’s cups up to the fill line.
1-3, Put the sample cup on the compass XRF sample loader, which is perfectly fit wit the sample cup dimension.
1-4, Click the ‘start’ button to run analysis. Results will be shown after 130 seconds.
>A set of commercially available heavy fuel oil standards with know sulfur concentrations were used to setup the calibration.
Figures 2-2 below shows the correlation curves sulfur in oil for high concentration ranges in percentage level.
This data was approximated with linear function. R2 is the coefficient of determination. An ideal correlation would have an R2 value of 1.
The red points are sulfur standards: Blank, 0.01%, 0.075%, 0.1%, 0.5%, 2% and 5%. The perfect R2 value(0.999921) demonstrate the good linear with wide concentrate range of sulfur.
Figures 2-3 below shows the correlation curves sulfur in oil for low concentration ranges in ppm level.
The red points are sulfur standards: Blank, 5ppm, 10ppm, 30ppm and 100ppm. The perfect R2 value(0.999664) demonstrate the good linear and high sensitivity for the low sulfur concentration analysis.
5.Conclusion
Sulfur analysis using ASTM D4294 and ISO 8754 continues to be an important measurement for refinery and independent laboratories around the world. Global regulation trends toward lower sulfur fuels demonstrate the need for a rapid and precise analysis solution. Based on the test results obtained above, it is proved that the Compass 4294 is capable of measuring sulfur in oil or fuel samples complying with the most strict standard.
On board fuel oil management is an important element of preventing operational issues and sulphur non-compliance.Improper handling of fuel oil on board may lead to non-compliance with MARPOL requirements,even if the fuel oil received was compliant. With it’s compact and portable design, Compass 4294 becomes essential tool to do on board oil quality control for sulfur.