Urgently need knowledge related to CEMS

CEMS measures sulfur dioxide, nitrogen oxides, and oxygen content. Nitrogen oxide detection requires converting nitrogen dioxide into nitric oxide for measurement.

1 SO2 Analyzer: Instrument model – NSA-3080A; Manufacturer – Shimadzu, Japan. Analysis method – Non-dispersive infrared absorption. Range – 0–100 mg/Nm3; customizable. Minimum detection limit – 10 mg/Nm3. Zero drift – ±1% of full scale per week. Total drift – ≤±2% of F.S. Linearity – ≤±1.5%. Response time – ≤180 seconds. Input/output signals – 4–20 mA. Output indicating the instrument’s operating status – Measurement/Fault/Alarm/Calibration/Backwashing, etc. Calibration method – Manual/automatic. Calibration cycle time – Automatic calibration every 24 hours. Instrument control and display system – Available. Weight of the instrument – Approximately 280 kg (excluding the standard gas cylinder). Dimensions of the instrument – 800 mm x 554 mm x 1806 mm. Power consumption – AC220V 50Hz, maximum power of 700 VA. Requirements for instrument air – Sample gas pressure: -5 to +1 Kpa.

2 O2 Analyzer: Instrument model – NSA-3080A; Manufacturer – Shimadzu, Japan. Analysis method – Electrochemical. Range – 0–25%. Minimum detection limit – 0.1%. Input/output signals – 4–20 mA. Output indicating the instrument’s operating status – Measurement/Fault/Alarm/Calibration/Backwashing, etc. Calibration method – Manual/automatic. Calibration cycle time – Automatic calibration every 24 hours. Instrument control and display system – Available

Thank you. I also want to ask: how are dust, temperature, and pressure in flue gas measured? Is samples taken separately for each parameter to be analyzed? ? How many analytical instruments are there in cabinets? ? ?

􀂙Flue gas pollutants mainly refer to dust particles, SO2, and NOx. • The main source of air pollution is thermal power plants, followed by steel mills and cement plants. Two-thirds of China’s electricity comes from thermal power generation, with coal being the main fuel. Chinese coal has a high sulfur and dust content, and many power plants, especially those of medium and small scale, lack equipment for desulfurization, denitrification, and dust removal, **which increases the levels of SO2, NO, and dust in the exhaust gases. • Controlling air pollution and reducing pollutant emissions is a systematic task. Taking thermal power plants as an example, it involves aspects such as combustion control, flue gas dust removal, sulfur compound removal, nitrogen oxide removal, and flue gas emission monitoring. Figure 14-1 is a schematic diagram of the production process for a coal-fired thermal power generation unit. It shows the online analysis tasks and the locations of sampling points related to boiler combustion control, as well as the monitoring of flue gas denitration, dust removal, and desulfurization processes, along with flue gas emission monitoring. CEMS is the abbreviation for Continuous Emission Monitoring System, which refers to a system for continuous monitoring of emissions from fixed pollution sources; in China, it is known as a continuous flue gas emission monitoring system. 􀂙 CEMS is mainly used in flue gas emission systems of fixed pollution sources such as power plant boilers, industrial/civilian boilers, industrial furnaces, municipal waste incinerators, and hazardous waste incinerators. 􀂙 CEMS can continuously and in real time monitor the concentrations (mg/m3) of particulate matter and gaseous pollutants, as well as their emission rates (kg/h, t/d, t/a) in the flue gases emitted by such fixed pollution sources. In other words, CEMS is an online monitoring system for flue gas emissions and a pollution discharge measurement system. CEMS consists of a particulate matter monitoring subsystem, a gaseous pollutant monitoring subsystem, a flue gas emission parameter measurement subsystem, and a data acquisition, transmission, and processing subsystem. 􀂙 Determine the concentrations of particulate matter and gaseous pollutants in the flue gas through sampling and non-sampling methods, while simultaneously measuring parameters such as flue gas temperature, flue gas pressure, flue gas flow velocity or flow rate, flue gas humidity (or incoming flue gas humidity), and flue gas oxygen content (or carbon dioxide content) ； 􀂙 Calculate pollutant concentrations and emissions in flue gas ； Display and print various parameters and charts, and transmit them to the fixed pollution source monitoring system via data and graphic transmission systems.

Temperature, pressure, and flow are field instruments, with their signals fed into the CEMS cabinet. The dust monitor is a field instrument; its signals can be fed into CEMS or directly into the data acquisition system. Some smoke and dust detectors come with temperature, pressure, and flow measurement functions

The original poster can first look at two sets of standards: HJT 75-2007 Technical Specifications for Continuous Monitoring of Flue Gas Emissions from Fixed Pollution Sources, and HJT 76-2007 Technical Requirements and Testing Methods for Continuous Monitoring Systems of Flue Gas Emissions from Fixed Pollution Sources

It takes some time to fully understand it. The regulations will be sufficient to last for a while.