GC5000 Volatile Organic Compounds Online Chromatography Monitoring System

Background introduction:

Photochemical smog pollution is one of the most prominent regional air pollution problems worldwide. It is mainly a process in which nitrogen oxides and volatile organic compounds in the troposphere undergo a series of complex photochemical reactions under special meteorological conditions (light, no wind or light breeze) to generate a series of secondary pollutants including ozone, peroxides, aldehydes and peroxyacetyl nitrates. Among these secondary pollutants, ozone accounts for the largest proportion. Numerous studies have shown that ozone poses a strong threat to human health, materials, and crops. With the acceleration of urbanization and industrialization, high concentration ozone pollution near the ground has become a severe atmospheric problem in most parts of China since the late 1990s.
Volatile Organic Compounds (VOCs) play a crucial role in the tropospheric photochemical oxidation cycle and are important precursors of secondary gaseous pollutants in cities and regions. They directly or indirectly control the generation rate and efficiency of photooxidants and have a significant impact on atmospheric oxidation potential. The composition of volatile organic compounds is complex and can usually be divided into several categories: non methane hydrocarbons (NMHCs), oxygenated volatile organic compounds (OVOCs), and halogenated hydrocarbons, among which non methane hydrocarbons account for the largest proportion.
The GC5000 instrument analysis system is designed with reference to the EPA PAMS standard, targeting C2-C12 hydrocarbons in volatile organic compounds as monitoring targets, providing accurate and representative long-term data for relevant departments to monitor ozone precursors; Enable relevant units in air pollution prevention and control to objectively grasp the air quality status, search for and establish a complete relationship between ozone, its precursors, and meteorological conditions, identify the causes of ozone pollution, and then study feasible prevention strategies.

Regarding PAMS:

PAMS stands for Photocatalytic Assessment Monitoring Stations, also known as Photochemical Assessment Monitoring Stations in Chinese. 1990The Clean Air Act Amendments have been passed, and the EPA requires states to establish photochemical assessment monitoring stations in areas with severe ozone pollution to comprehensively monitor ozone and ozone precursors to understand the causes of ozone pollution.

AMA GC5000 system composition:

GC5000 volatile organic compounds online chromatographic monitoring system is developed, designed and manufactured by German AMA Instruments with 20 years of experience. It has advanced technology, stable performance and no need for personnel to be on duty.

The system has high detection sensitivity at the PPT level, designed according to the EPA PAMS standard, and optimized for long-term monitoring of C2-C12 hydrocarbons in ozone precursors.

At present, the GC5000 series has been widely used in air quality monitoring networks in countries such as Germany, the Netherlands, Belgium, Greece, Brazil, Italy, Spain, and South Korea. In addition, super stations in Berlin, Taipei, and Seoul are also using this system.

This set of equipment has been selected for atmospheric environment monitoring systems in cities such as Beijing, Nanjing, Guangzhou, Tianjin, and Shenzhen. Meanwhile, the system has been applied to monitor the atmospheric environmental quality of the Guangzhou Asian Games.

Core equipment:

*GC5000 VOC analysis chromatography (target compounds C2-C5);

*GC5000 BTX analysis chromatography (target compounds C6-C12);

*DIM200 dynamic calibrator (maximum dilution factor 2500);

Auxiliary equipment:

*Gas source: high-purity nitrogen, high-purity hydrogen, compressed air;

*Gas pretreatment device, purifying carrier gas and auxiliary gas;

*PAMS standard gas (56 mixed standard samples, 1ppm);

*Data computer;

*19 'standard cabinet;

Related functions:

In order for users to easily understand the condition of the instrument, view spectra and data, AMA software intelligently monitors and analyzes the operation status of the chromatography, and saves records of monitoring, calibration, power outages, and other events that occur during the system's operation, making it convenient for users to trace the system status and data quality.

Through the network, users can remotely log in to the system interface and check the operating status. Maintenance engineers can provide remote assistance to improve system maintenance efficiency. Simultaneously analyze the chromatographic data and backup it to the data industrial computer (txt file) to prevent instrument damage and loss of original data.

Technical specifications:

The system technical indicators comply with the EU andEPA's regulatory requirements for monitoring ozone precursors in the atmosphere

* the VDI guideline 2100 of the EU guideline 2002/3/EC ，from February 12th 2002；

* the guidelines of the Technical Assistance Document EPA/600-R-98/161 of US EPA，from September 30th 1998。

Technical features:

Accurate control of sampling flow rate and sample volume: GC5000 chromatography uses a mass flow meter to control the sampling flow rate and accumulate the sample volume, which can avoid the influence of environmental pressure and temperature.

Two level sample enrichment technology (for low-carbon components): Two level sample enrichment technology can provide high-capacity sample enrichment volume (penetration volume for C2 compounds greater than 800ml), as well as sample focusing ability (ensuring high chromatographic peak separation and excellent peak shape)

Note: In the chromatogram on the right, the numbers are 1-ethane; 2-Ethylene; 3-Propane;

The working temperature of the adsorption tube is greater than 10 ° C: The working temperature of the adsorption tube during the sample enrichment and focusing stages is higher than 10 ° C to avoid freezing of the enrichment module. Suitable for long-term operation of unmanned observation stations;

Polar reverse extraction column as a pre column: Polar reverse extraction column can intercept high boiling point organic compounds and water vapor in ambient air samples. Avoid prolonging the analysis cycle caused by high boiling point substances other than the target compound; Avoid chromatographic peak identification errors caused by water vapor induced chromatographic retention time shift. Meanwhile, the intercepted substances will be blown out of the pre column in reverse during the analysis cycle.

60m capillary chromatography column: A long chromatography column can achieve the highest separation efficiency, providing assurance for excellent analysis of numerous target compounds.

All electric controls: The system adopts all electric controls internally, which can effectively reduce the maintenance of the instrument compared to pneumatic controls. At the same time, it avoids gas loss that may occur during the use of pneumatic valves due to gas leakage.

Performance parameters:

GC5000 VOC Chromatography Analyzer

Function: Automatic 24-hour continuous sampling throughout the day, using two-stage enrichment and chromatographic column for separation and analysis of C2~C5 organic species;

Range: 0~300ppb;

Detection limit: 0.05ppb (propane as an example);

Analysis cycle: 30-60 minutes;

Sampling:

Sampling time: 0-99min (adjustable);

Flow rate: 10~50 ml/min (adjustable);

Mass Flow Control Meter (MFC) control;

Sampling volume: 200~800 ml (adjustable);

Enrichment:

Bipolar enrichment:

Primary enrichment column: Sampling temperature of 15 ° C, maximum thermal analysis temperature of 350 ° C;

Secondary enrichment column: Focusing temperature of 20 ° C, maximum thermal decomposition temperature of 350 ° C;

Heating speed: maximum 40 ° C/s;

Chromatography column box:

Quartz glass capillary column, length 30m~60m;

Column box temperature range: 40-210 ° C;

Heating rate: 1-25 ° C/min (increasing by 1 ° C/min);

Carrier gas: N2, 99.999%, 3bar;

FID hydrogen flame ionization detector;

Require hydrogen (H2) and combustion air supply;

Hydrogen, 99.999%, 3bar;

Combustion air, 99.999%, 3bar;

Calibration: Allow single/multi-point calibration;

Output: Intelligent display of graphs, parameter specifications, operating status, etc. Various parameter settings, editing, and result processing operations can be completed through the system menu;

Power supply: 220V 50HZ;

Operating environment:

Temperature: 0~40 ° C (if the temperature exceeds the temperature range, air conditioning needs to be installed);

Relative humidity: 5~95% without condensation;

Appearance: 19 "x 6 HU x 600mm, standard chassis, weight 35 kg;

GC5000 BTX Chromatographic Analyzer

Function: Automatic 24-hour continuous sampling throughout the day, using single-stage enrichment and chromatographic column for separation and analysis of C6-C12 organic species;

Range: 0~300ppb;

Detection limit: 0.03ppb (benzene as an example);

Analysis cycle: 30-60 minutes;

Sampling:

Sampling time: 0~99min (adjustable)

Flow rate: 10~50 ml/min (adjustable)

Mass Flow Control Meter (MFC) Control

Sampling volume: 200~800 ml (adjustable)

Enrichment:

Enrichment column: Sampling temperature of 30 ° C, maximum thermal analysis temperature of 350 ° C;

Heating speed: maximum 40 ° C/s;

Chromatography column box: quartz glass capillary column, length 30m~60m;

Column box temperature range: 40-210 ° C;

Heating rate: 1-25 ° C/min (increasing at 1 ° C/min);

Carrier gas: N2, 99.999%, 3 bar;

FID hydrogen flame ionization detector

Require hydrogen (H2) and combustion air supply;

Hydrogen, 99.999%, 3 bar;

Combustion air, 99.999%, 3 bar;

Calibration: Allow single/multi-point calibration;

Output: Intelligent display of graphs, parameter specifications, operating status, etc. Various parameter settings, editing, and result processing operations can be completed through the system menu;

Power supply: 220V 50Hz;

Operating environment:

Temperature: 0~40 ° C (if the temperature exceeds the temperature range, air conditioning needs to be installed);

Relative humidity: 5~95%, no condensation;

Appearance: 19 "x 6 HU x 600mm, standard chassis, weight 35 kg;

DIM 200 calibration module

Function:

(1) Under the control of GC5000BTX chromatographic analyzer, switch the flow path required for sampling and calibration;

(2) Accurately control the flow rates of zero gas and standard gas to calibrate the chromatographic system, with dilution ratios ranging from 1 to 2500;

Supply gas:

Zero gas (pure air or nitrogen), 3 bar;

Standard gas: 3 bar;

Sample gas;

Flow control:

Standard gas: 2-100 ml/min;

Zero gas: 100~5000ml/min;

Accuracy: Measurement value ± 0.5%;

Mass Flow Control Meter (MFC) control;

Two (optional) working modes:

(1) Connect the AMA chromatography system through an internal communication channel, controlled by the chromatography system software, and can perform up to 20 points of automatic calibration or inspection

(2) When installing optional independent operating software or external control interfaces to achieve autonomous operation or remote control through external digital I/O connection, up to 5 points of automatic calibration or inspection can be performed

Power supply: 220V 50Hz;

Operating environment:

Temperature: 0~40 ° C (if the temperature exceeds the temperature range, air conditioning needs to be installed);

Relative humidity: 5~95%, no condensation;

Appearance: 19 ", 3H standard chassis, weight 4 kg

System application:

Professor Zhu Bin from the School of Atmospheric Physics at Nanjing University of Information Science and Technology used the GC5000 system to analyze VOCs (C2-C12) in the atmospheric environment. The concentration of VOCs varied under different wind directions, and different emission sources contributed differently to the total amount of VOCs. The concentration of VOCs was mainly affected by wind direction, indicating that the initial emission of VOCs came from the local area, and in the northeast region of the city, the concentration of VOCs was affected by regional transmission. Through the evaluation of potential methods for the formation of propylene homologues and ozone, this study aimed to investigate the impact of wind direction on VOCs concentration. Indicating that olefins contribute 57% -58% to the chemical formation of ozone, using principal component analysis/absolute principal component receptor model analysis. The results indicate that in this region, 39% of VOCs mainly come from vehicle emissions, while solvent use and industrial sources account for 36%.