Calcium Carbide Furnace Tail Gas Purification Gas Analyzer

      The TR-9300V Online Continuous VOCs Gas Monitoring System is an online monitoring system based on gas chromatography technology. It can monitor volatile organic compounds (including methane, non-methane total hydrocarbons, benzene series, etc.) in gases online, and can also be extended to monitor other volatile components (such as ketones, esters, and other organic compounds) according to user requirements, featuring 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, ensuring high reliability;

l  The system adopts a full thermal method, maintaining high temperatures from sampling to analysis, eliminating the need for dehumidification, 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, requiring no值守, and minimizing manual maintenance;

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

l  Optional explosion-proof design, using a positive pressure explosion-proof cabinet, allowing installation in explosion-proof areas, ensuring safety and reliability.

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, among others.

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 operational status information, while also generating reports, storing data, recording historical data, and communicating with environmental protection departments.

    Table 2-1 Names of Components in 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 shows the gas flow diagram of the pre-treatment system, which helps users understand the gas flow direction of the entire system and serves as a reference for daily maintenance.

The diagram shows the case of two probes, which can be used for monitoring at two different points in 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 to automatically measure and analyze methane and total hydrocarbon content. The non-methane total hydrocarbon content is calculated by the difference between total hydrocarbons and methane content, significantly shortening the analysis cycle. At the same time, the high-temperature heated technology developed for high-boiling-point non-methane total hydrocarbons greatly reduces chromatographic peak broadening, 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, ensuring precise and stable pressure control with an accuracy better than ±0.05 kPa.

l   Uses EFC technology for hydrogen and air flow control, with 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 for up to (6~8) years.

l   19'' standard chassis, compact structure, can be integrated 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 junction box, upper computer, organic waste gas online monitoring system monitoring software, and data remote transmission unit.

The junction box is installed on an outdoor platform. All equipment on the platform is powered by the junction box, and the junction box receives output signals from all equipment, converting them into the RS485 protocol commonly used in industrial sites through an internal processing unit, and transmitting them to the upper computer. The organic waste gas online monitoring system monitoring software installed on the upper computer monitors and queries all measurement information and instrument operational status information. 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 supply is mainly connected to the VOC gas analyzer carrier gas, FID detector supply gas, pneumatic valve drive gas, probe and backflushing box backflushing gas, etc. Except for the probe and backflushing box backflushing gas, which require a separate high-pressure compressed air supply, other gas paths are supplied by gas generators or high-pressure gas cylinders delivered with the system.

Gas for the VOC analyzer and FID detector is mainly connected to the gas source interfaces on the back of the VOC analyzer equipment, respectively: carrier gas, zero gas, bypass vent, calibration gas, hydrogen, and 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 large flow gas collected from flue gas, interface is OD8 mm fluoropolymer tube.
• Calibration Gas: Used to provide standard gas for the instrument, interface is OD1/8” fluoropolymer tube.
• Hydrogen: Used to provide hydrogen for the instrument, interface is OD1/8” fluoropolymer tube.
• Reserved: Used to connect 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 Requirements

• Cabinet Power Supply: 220 V AC, power 2 kW (excluding heated line);
• 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 conditions, select an appropriate power supply.
• Total System Power Supply: Sum of the cabinet power supply and heated line power supply.

1.1.4 Pre-Power-On Checks

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 connected with a tube to the outdoors.

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, and 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 undergoes strict verification and accurate calibration before leaving the factory. Due to different on-site conditions, recalibration is recommended during initial use. As internal electronic components age, system parameters will slowly drift, affecting measurement accuracy. Therefore, to ensure accurate measurement results, various analyzers in the system need to be recalibrated periodically during use.

Calibration mainly involves zero point and sensitivity calibration, requiring the introduction of zero gas and standard gas of corresponding concentrations.

1.1.6 Adjusting High-Pressure Gas Cylinders

As shown in Figure 3-6, gas cylinders generally contain high-pressure gas, so a two-stage pressure regulator must be connected at the cylinder outlet (controlled by the cylinder valve) to reduce pressure before use. The two-stage pressure regulator has two gauges: the one closer to the cylinder is the high-pressure gauge, which automatically displays the remaining pressure in the cylinder after the valve is opened; the one farther from the cylinder is the outlet pressure gauge, which can be used to adjust the required output gas pressure.

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