Volatile VOC Online Monitoring Analyzer

      The TR-9300 online VOCs gas continuous monitoring system is an online monitoring system based on gas chromatography technology. It can monitor volatile organic compounds in gases online (including methane, non-methane total hydrocarbons, benzene series, etc.), and can also be extended to monitor other volatile components (such as ketones, esters, and other organic compounds) according to user requirements, with high measurement accuracy and a wide dynamic range. This system is suitable for monitoring organic compound emissions from industrial stationary pollution sources such as petrochemicals, rubber products, semiconductor manufacturing, pharmaceuticals, printing, spraying, organic solvent manufacturing, and automotive manufacturing. For details, please contact: Jia Weihao, Xi'an Juneng Instrument Co., Ltd. 15891421187   18789429991

1.1 System Features

The online monitoring system for organic waste gas has the following features:

l  Uses gas chromatography for detection, complying with international detection standards for VOCs detection methods;

l  Pre-treatment methods comply with U.S., EU, and domestic standards for stationary pollution source waste gas measurement, with high method reliability;

l  The system adopts a full thermal method, maintaining high temperatures from sampling to analysis, eliminating the need for dewatering, effectively avoiding sample loss, and ensuring accurate and reliable monitoring data;

l  Equipped with a fast bypass flow path, ensuring rapid instrument sampling response;

l  Features automatic purging function, automatically removing dust from the probe filter surface, extending the probe's service life;

l  Includes automatic calibration function, supporting full-process automatic calibration, no need for值守, minimizing manual maintenance;

l  The system can monitor total hydrocarbons, methane, non-methane total hydrocarbons, benzene series, odorous gases, and hundreds of organic waste gases, meeting the monitoring needs of different customers;

l  Optional explosion-proof design, using positive pressure explosion-proof cabinet design, can be installed in explosion-proof areas, safe and reliable.

1.2 Main Technical Parameters

   Table 1-1 Main technical parameters of the organic waste gas online monitoring system

2 System Composition

The organic waste gas online monitoring system consists of two parts: the VOCs (methane, non-methane total hydrocarbons, benzene series) monitoring subsystem and the data acquisition and processing subsystem, as shown in Figures 2-1 and 2-2.

The VOCs monitoring subsystem mainly consists of a sampling probe, heated line, pre-treatment unit, electrical control unit, VOCs analyzer, and auxiliary systems. During measurement, flue gas is extracted by an external high-temperature pump in the cabinet, passed through the sampling probe, heated line, and dust filter, and then introduced into the VOCs analyzer for measurement. The instrument's auxiliary systems include a zero gas generation unit, hydrogen generator, and calibration gas, etc.

The data acquisition and processing subsystem consists of an industrial PC and the organic waste gas online monitoring system software. The organic waste gas online monitoring system software is installed on the external industrial PC and is used to monitor and summarize all gas concentration information and working status information, while also generating reports, storing data, recording historical data, and communicating with environmental protection departments.

    Table 2-1 Names of various parts of the waste gas treatment VOC cabinet

2.1 Gaseous Pollutant Monitoring Subsystem

2.1.1 Sampling Pre-treatment System

The sampling pre-treatment system consists of a sampling unit, calibration unit, backflushing unit, and electrical control unit.

Figure 2-4 is the gas path flow chart of the pre-treatment system. This chart helps users understand the gas flow direction of the entire system and also serves as a reference for daily maintenance.

The figure shows the case of two probes, which can be used for monitoring at two different points with the same system. Users can also configure a single sampling probe for single-point monitoring according to their needs.

2.1.2 VOC Gas Analyzer

The VOC gas analyzer uses high-temperature heated dual-column parallel backflushing chromatography separation technology, which can automatically measure and analyze the content of methane and total hydrocarbons. The content of non-methane total hydrocarbons is calculated by the difference between total hydrocarbons and methane content,大大 shortening the analysis cycle. At the same time, the high-temperature heated technology developed for high-boiling-point non-methane total hydrocarbons significantly reduces the chromatographic peak broadening of high-boiling-point non-methane total hydrocarbons, allowing the instrument to accurately measure high-boiling-point substances, even in the presence of high concentrations of non-methane total hydrocarbons.

The commonly used VOC gas analyzer is a methane non-methane total hydrocarbon analyzer. In addition to the separation and measurement systems of conventional chromatographs, the VOC gas analyzer provides flexible touch-screen operation software, automatic calibration, and measurement functions. Furthermore, the VOC gas analyzer has the following features:

l   Uses EPC technology for carrier gas pressure control, with precise and stable pressure control, pressure control accuracy better than ±0.05 kPa.

l   Uses EFC technology for hydrogen and air flow control, flow control accuracy better than 0.5% F.S.

l   Column oven control accuracy better than ±0.1°C.

l   Uses low-maintenance diaphragm pumps and sample loops for fixed-volume sampling.

l   Uses imported VALCO ten-port/six-port valves, with low maintenance and long service life.

l   Uses dual-column parallel backflushing technology to analyze non-methane total hydrocarbons, reducing peak broadening and shortening analysis time.

l   Uses a micro FID detector, which is highly sensitive to methane and total hydrocarbons.

l   Built-in standard industrial PC, high-definition color LCD touch screen, excellent human-machine interaction control software interface, based on Microsoft Windows operating system, enabling fully automatic unmanned operation of the entire system. All maintenance and diagnostic functions can be performed via the touch screen, and instrument parameters and analysis methods can be edited and set. Real-time display of instrument operating status, chromatograms, and results. Automatic data and graph storage, storage time up to (6~8) years.

l   19'' standard chassis, compact structure, can be integrated and installed with similar instruments in a vertical cabinet, small footprint, convenient daily maintenance and operation.

2.2 Data Acquisition and Processing Subsystem

The data acquisition and processing subsystem consists of a hub box, upper computer, organic waste gas online monitoring system monitoring software, and data remote transmission unit, etc.

The hub box is installed on an outdoor platform. All equipment on the platform is powered by the hub box. Meanwhile, the hub box receives output signals from all equipment, converts them into the RS485 protocol commonly used in industrial sites through an internal processing unit, and transmits them to the upper computer. All measurement information and instrument working status information are monitored and queried through the organic waste gas online monitoring system monitoring software installed on the upper computer. The upper computer software can simultaneously generate data required by national environmental protection departments and transmit it to environmental protection administrative departments via data remote transmission units (GPRS, Internet, etc.).

1. For the functions and operation methods of the organic waste gas online monitoring system monitoring software, please refer to Section 3: Organic Waste Gas Online Monitoring System Monitoring Software Operation. For details, please contact: Jia Weihao, Xi'an Juneng Instrument Co., Ltd. 15891421187   18789429991

Preparations Before System Operation

1.1.2 Gas Path Connection and Settings

The system gas path supply is mainly connected to the VOC gas analyzer carrier gas, FID detector supply, pneumatic valve drive gas, probe and backflushing box backflushing gas, etc. Among these, the probe and backflushing box backflushing gas require a separate supply of high-pressure compressed air, while other gas path supplies are provided by gas generators or high-pressure cylinder gases shipped with the system.

Gases for the VOC analyzer and FID detector are mainly connected from the gas source interfaces on the back of the VOC analyzer equipment, respectively: carrier gas, zero gas, bypass vent, calibration gas, hydrogen, reserved.

• Carrier gas: Serves as the carrier gas for the analyzer, generally zero gas generated by the zero gas generator, interface is OD1/8” fluoropolymer tube.
• Zero gas: Serves as the combustion-supporting gas for the FID detector, interface is OD1/8” fluoropolymer tube.
• Bypass vent: Used to discharge the large flow of gas collected from the flue gas, interface is OD8mm fluoropolymer tube.
• Calibration gas: Standard gas provided to the instrument, interface is OD1/8” fluoropolymer tube.
• Hydrogen: Hydrogen provided to the instrument, interface is OD1/8” fluoropolymer tube.
• Reserved: For connecting an external pump, interface is OD1/8” fluoropolymer tube.

1.1.3 Electrical Wiring and Requirements

System Power Supply

X2:1, X2:2, X2:3 of the electrical control board are the live wire, neutral wire, and ground wire terminals for the 220 V system power supply, respectively.

Power Supply Requirements

• Cabinet power supply: 220 V AC, power 2 kW (excluding heated lines);
• Heated line power supply: 220 V AC, power (kW) = heated line length (m) × 0.04 kW/m. Based on the actual length of the heated line and the on-site power supply situation, select an appropriate power supply.
• Total system power supply: The sum of the cabinet power supply and the heated line power supply.

1.1.4 Pre-power-on Check

Generally, before powering on the system, the following points should be checked:

• The system is well grounded.
• Instrument air (0.4~0.7) MPa should be prepared and connected.
• Hydrogen (0.1~0.4) MPa should be prepared and connected.
• The system bypass vent should be led outdoors with a gas tube.

1.1.5 Power-on Sequence

The system power-on sequence is: Main switch → Other branch switches → Multi-function socket switch → AQMS-100 zero gas generator switch → VOC analyzer instrument switch.

After the system is powered on, the GC instrument requires about 30 minutes of preheating, the probe and heated line require about 60 minutes of preheating. After all temperature and pressure indicators meet requirements and the instrument has no fault alarms, the system automatically or manually triggers into measurement state.

System Calibration

The organic waste gas online monitoring system is strictly verified and accurately calibrated before leaving the factory. Due to different on-site working conditions, it is recommended to recalibrate when first used. As the internal electronic components age, system parameters will slowly drift, affecting measurement accuracy. Therefore, to ensure accurate measurement results of the organic waste gas online monitoring system, various analyzers组成 the system need to be recalibrated periodically during use.

Calibration mainly involves zero point and sensitivity calibration of the system. During calibration, zero gas and standard gases of corresponding concentrations need to be introduced.

1.1.6 Adjusting High-Pressure Gas Cylinders

As shown in Figure 3-6, generally, gas cylinders contain high-pressure gas. Therefore, when using the gas, a two-stage pressure regulator needs to be connected at the cylinder outlet (controlled by the cylinder valve) to reduce the pressure before use. The two-stage pressure regulator has two gauges. The one closer to the cylinder is the high-pressure gauge. When the cylinder valve is opened, it automatically displays the remaining pressure in the cylinder. The one farther from the cylinder is the outlet pressure gauge, through which the required output gas pressure value can be adjusted.

• Opening the gas cylinder: The sequence for opening the gas cylinder is to first open the cylinder valve (counterclockwise), then slowly open the two-stage pressure regulator to the appropriate pressure. To ensure the reliability and accuracy of the standard, generally adjust the reading of the outlet pressure gauge (clockwise) to about 0.3 MPa.
• Closing the gas cylinder: The sequence for closing the gas cylinder is to first close the cylinder valve (clockwise), then close the switch on the two-stage pressure reducing valve (counterclockwise). When the reading of the outlet pressure gauge drops to 0 MPa, it is done. After closing the cylinder valve, the calibration value is unreliable and is not recommended for further use. For details, please contact: Jia Weihao, Xi'an Juneng Instrument Co., Ltd. 15891421187   18789429991