CN118111916A - Carbon emission on-line monitoring system based on off-axis integral cavity spectrum technology - Google Patents

Abstract

The invention discloses a carbon emission online monitoring system based on an off-axis integral cavity spectrum technology, which comprises a flue gas sampling module, a preprocessing module, a flue gas analyzer, a data acquisition module and a control module, wherein the flue gas sampling module is used for sampling carbon emission; the flue gas sampling module comprises a sampling probe rod, a sampling probe, a heat tracing pipeline and a secondary filter. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology adopts the TDLAS and OA-ICOS technology to realize ppb-ppm detection of near-infrared carbon dioxide, carbon monoxide and methane, realizes online detection and quick response, and simultaneously can directly obtain data such as carbon dioxide emission in real time by combining parameters such as flue gas flow rate, humidity and the like; the key components adopt an anti-corrosion and back-blowing process so as to adapt to severe environments such as high humidity and high dust and strong corrosiveness possibly existing in industrial flue gas of coal-fired power plants, gas power plants and the like and ensure accurate measurement results.

Description

An online monitoring system for carbon emissions based on off-axis integrating cavity spectroscopy

Technical Field

The present invention belongs to the technical field of carbon emission monitoring, and in particular relates to an online carbon emission monitoring system based on off-axis integrating cavity spectroscopy technology.

Background technique

Carbon emissions is a general term or abbreviation for greenhouse gas emissions. Carbon emissions mainly affect the temperature of the earth's atmosphere. Carbon emissions generally refer to the emission of greenhouse gases, which causes the greenhouse effect and thus raises global temperatures. Currently, carbon emissions are considered to be one of the main causes of global warming. With the continuous acceleration of the industrialization process, a large amount of harmful gases, such as nitrogen oxides and sulfur dioxide, will be released during the burning of fossil fuels. These waste gases will form ozone and fine particulate matter when mixed into the air, which will damage human health and vegetation growth.

A large amount of flue gas emissions will be generated during the operation of coal-fired and gas-fired power plants, so coal-fired and gas-fired power plants are also one of the "big carbon emitters". Monitoring the emissions and emission data of coal-fired and gas-fired power plants can intuitively reflect the coal combustion efficiency and help companies understand the production and operation status. The monitoring system continuously samples and analyzes to measure the gas concentration and particulate matter concentration in the flue gas. At the same time, the concentration of pollutants and the total emissions can be obtained through calculation.

However, many existing monitoring systems do not contain a carbon dioxide concentration measurement module, and the detection results take a long time and cannot respond quickly. In addition, if direct measurement is used, the analyzer is in direct contact with the flue gas, which is easily corroded by the flue gas and blocked by impurities in the flue gas. It is not very convenient to use and maintain. In addition, due to the interference of factors such as moisture and vibration, the measurement of flue gas flow rate and concentration is prone to large errors. The extraction sampling system is complex, and the accuracy requirements of the analyzer are high, which increases the cost of use.

Summary of the invention

The purpose of the present invention is to provide an online carbon emission monitoring system based on off-axis integrating cavity spectroscopy technology, which adopts TDLAS and OA-ICOS technologies to realize ppb-ppm level detection of near-infrared carbon dioxide, carbon monoxide and methane, online detection, and rapid response. At the same time, combined with the measurement of flue gas flow rate, humidity and other parameters, data such as carbon dioxide emissions can be directly obtained in real time; key components adopt corrosion resistance and backblowing technology to adapt to the harsh environment of high humidity, high dust and strong corrosiveness that may exist in industrial flue gas such as coal-fired power plants and gas-fired power plants, to ensure accurate measurement results.

To achieve the above-mentioned objectives, the present invention provides an online carbon emission monitoring system based on off-axis integrating cavity spectroscopy technology, including a flue gas sampling module, a pretreatment module, a flue gas analyzer, a data acquisition module and a control module; the flue gas sampling module includes a sampling probe rod, a sampling probe, a heating pipeline, and a secondary filter.

Preferably, a ceramic filter is provided inside the sampling probe in the flue gas sampling module to remove dust in the sample gas; and a heater is provided outside the sampling probe to prevent condensation of water after the sample gas passes through the sampling probe.

Preferably, the sampling probe rod and the sampling probe are both made of special acid-resistant stainless steel, the heating pipeline is a customized Φ8 polytetrafluoroethylene heating pipe, and the secondary filter is made of ceramic material.

Preferably, the heating pipeline runs from the flue gas analyzer to the sampling probe, and the heating pipeline provides a backflush channel to meet the backflush needs of the control module.

Preferably, the heating method of the heating pipeline is electric heating, and a temperature sensor is provided in the heating sleeve of the heating pipeline. The temperature sensor is controlled by the temperature controller in the control module and provides a heating temperature alarm signal output.

Preferably, the pretreatment module includes a first-level rapid condensation and water removal, and a second-level condensation and fine filtration; the control module realizes automatic backwashing, automatic calibration, and refrigeration temperature alarm prompt functions, and displays various working states of the system.

Preferably, the flue gas analyzer adopts TDLAS and OA-ICOS technologies, and is provided with a sampling pump and a drainage system.

Therefore, the present invention adopts the above-mentioned carbon emission online monitoring system based on off-axis integrating cavity spectroscopy technology, and adopts TDLAS and OA-ICOS technology to realize ppb-ppm level detection of near-infrared carbon dioxide, carbon monoxide and methane, online detection, and rapid response; at the same time, combined with the measurement of flue gas flow rate, humidity and other parameters, data such as carbon dioxide emissions can be directly obtained in real time.

Compared with the existing method, the present invention has the following advantages:

1. Based on TDLAS, the present invention adopts an off-axis integrating cavity (OA-ICOS) to replace the traditional multi-pass cell, which increases the effective range to more than ten kilometers to tens of kilometers without increasing the cost, thereby effectively improving the detection accuracy;

2. The measurement technology used in the present invention is gas selectivity, and the detection accuracy is much better than the existing spectrometer gas detection technology;

3. The present invention matches the corresponding flue gas sampling and pretreatment technologies to form an online flue gas monitoring system suitable for coal-fired and gas-fired power plants, achieving the characteristics of high sensitivity, high selectivity, fast response speed, adaptability to harsh environments, and real-time online monitoring of multiple components.

The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the TDLAS+OA-ICOS principle of an embodiment of an online carbon emission monitoring system based on off-axis integrating cavity spectroscopy technology according to the present invention;

FIG2 is a schematic diagram of a sampling preprocessing measurement method of an embodiment of a carbon emission online monitoring system based on off-axis integrating cavity spectroscopy technology of the present invention;

FIG3 is a flowchart of a working process of an online carbon emission monitoring system according to an embodiment of the present invention, which is a system for online carbon emission monitoring based on off-axis integrating cavity spectroscopy technology.

Detailed ways

The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

Embodiment 1

As shown in Figure 1, an online carbon emission monitoring system based on off-axis integral cavity spectroscopy technology includes a flue gas sampling module, a preprocessing module, a flue gas analyzer, a data acquisition module and a control module. The sample gas is collected through the flue gas collection module and enters the measuring gas chamber in the flue gas analyzer. The analog signal of the flue gas analyzer transmits the data to the touch screen integrated industrial computer through the data acquisition module. In the touch screen integrated industrial computer, the flue gas concentration is converted into a standard state according to parameters such as particulate matter, temperature, pressure, flow rate, humidity, etc., and the total amount of each flue gas pollutant is calculated to generate a report that meets environmental protection requirements (including: time, concentration, temperature, humidity, operating status, etc.); the touch screen integrated industrial computer can collect concentration data through the RS485 interface, and realize functions such as conversion, storage, summary, report output, and sending data to the data acquisition instrument.

The flue gas collection module includes a sampling probe, a sampling probe, a heating pipeline, and a secondary filter. The sampling probe is equipped with a ceramic filter element to remove dust from the sample gas. A heater is installed outside the sampling probe to prevent the sample gas from generating condensed water after passing through the sampling probe. The sampling probe and the sampling probe are both made of special acid-resistant stainless steel, the heating pipeline is a customized Φ8 polytetrafluoroethylene heating pipe, and the secondary filter is made of ceramic material.

The heat tracing pipeline runs from the flue gas analyzer to the sampling probe. The heat tracing pipeline provides a backflush channel to meet the backflush needs of the control module. The heating method of the heat tracing pipeline is electric heating. A temperature sensor is provided in the heating sleeve of the heat tracing pipeline. The temperature sensor is controlled by the temperature controller in the control module and provides a heat tracing temperature alarm signal output.

The pretreatment module includes a first-stage rapid condensation and water removal, and a second-stage condensation and fine filtration. The first-stage rapid condensation and water removal ensures that the gas composition remains unchanged, and the second-stage condensation and fine filtration ensures that the gas measurement chamber is not contaminated, thereby extending the service life of the analyzer.

When the sample gas enters the sampling probe through the sampling probe rod, it is filtered by the ceramic filter element to remove dust from the sample gas. The sampling probe is heated to 120℃～150℃ by the heater to prevent the sample gas from generating condensed water after passing through the sampling probe. The sample gas from the sampling probe passes through the high-temperature heating pipeline and the secondary filter for dust removal. After the first-level rapid condensation and water removal in the pretreatment module and the second-level condensation fine filtration, it directly enters the measuring gas chamber in the flue gas analyzer. The flue gas analyzer uses TDLAS and OA-ICOS technology to measure the flue gas. The flue gas analyzer is equipped with a sampling pump and a drainage system. Finally, the measured flue gas is emptied through the sampling pump, and the condensed water is discharged through the drainage system.

The control module can realize automatic backflush, automatic calibration, refrigeration temperature alarm prompt functions, and can display various working states of the system. As shown in Figure 2, the flue gas analyzer will enter the calibration state for automatic zeroing at regular intervals. At this time, the control module switches to the backflush gas circuit, and the zeroing valve is opened. Under the action of the internal sampling pump of the flue gas analyzer, the ambient air passes directly into the gas chamber to purge the residual measured gas in the gas chamber, thereby achieving zeroing and oxygen range calibration. At the same time as zeroing, the control module controls the backflush ball valve to open or close to achieve backflush of the filters in the heating pipeline and sampling probe. After the equipment has been running for a period of time, the system switches the sampling valve to the backflush gas circuit, and performs pulse backflush on the sampling probe by controlling the opening and closing of the backflush electric ball valve, thereby ensuring that the measurement channel is not blocked during long-term use. When the system is fully calibrated, the sampling valve switches to the calibration gas circuit, the calibration solenoid valve opens, and the calibration gas passes through the heating pipeline and condenser and enters the gas chamber, thereby achieving system calibration.

When this embodiment is used specifically, as shown in FIG3 , the sampling probe samples the flue gas, and the sample gas enters the flue gas analyzer through the heat tracing pipeline. The three flue gases in the flue gas analyzer (1-3 can be installed according to the situation) are mixed, pre-treated, and measured to obtain the concentrations of carbon dioxide, carbon monoxide, and methane. The flue gas analyzer transmits the concentration, flow, oxygen content, pressure, temperature, humidity, and other parameters of carbon dioxide, carbon monoxide, and methane to the touch screen integrated industrial computer through analog signals. In the touch screen integrated industrial computer, the flue gas concentration is converted into a standard state according to the parameters such as particulate matter, temperature, pressure, flow rate, and humidity, and the total amount of each flue gas pollutant is calculated, and a report that meets environmental protection requirements is generated (including: time, concentration, temperature, humidity, operating status, and other information).

Therefore, the present invention adopts the above-mentioned carbon emission online monitoring system based on off-axis integral cavity spectroscopy technology, adopts TDLAS and OA-ICOS technology, realizes ppb-ppm level detection of near-infrared carbon dioxide, carbon monoxide and methane, online detection, and rapid response; at the same time, combined with the measurement of flue gas flow rate, humidity and other parameters, directly obtains data such as carbon dioxide emissions in real time. The key components adopt corrosion resistance and backwashing technology to adapt to the harsh environment of high humidity, high dust and strong corrosiveness that may exist in the flue gas of coal-fired and gas-fired power plants, and ensure accurate measurement results.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims (7)

1. A carbon emission on-line monitoring system based on off-axis integral cavity spectrum technology is characterized in that: the system comprises a flue gas sampling module, a preprocessing module, a flue gas analyzer, a data acquisition module and a control module; the flue gas sampling module comprises a sampling probe rod, a sampling probe, a heat tracing pipeline and a secondary filter.

2. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology according to claim 1, wherein: a ceramic filter element is arranged in a sampling probe in the flue gas sampling module to remove dust in the sample gas; the heater is arranged outside the sampling probe to prevent the sample gas from generating condensed water after passing through the sampling probe.

3. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology according to claim 1, wherein: the sampling probe rod and the sampling probe are both made of special acid-resistant stainless steel, the heat tracing pipeline is a customized phi 8 polytetrafluoroethylene heat tracing pipe, and the secondary filter is made of ceramic materials.

4. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology according to claim 1, wherein: the heat tracing pipeline is from the flue gas analyzer to the sampling probe, and provides a blowback channel to meet the requirement of blowback of the control module.

5. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology according to claim 1, wherein: the heating mode of the heat tracing pipeline is electric heating, a temperature sensor is arranged in a heating sleeve of the heat tracing pipeline, and the temperature sensor is controlled by a temperature controller in the control module and provides heat tracing temperature alarm signal output.

6. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology according to claim 1, wherein: the pretreatment module comprises primary rapid condensation water removal and secondary condensation fine filtration; the control module realizes the functions of automatic back blowing, automatic calibration and refrigeration temperature alarm prompt and displays various working states of the system.

7. The carbon emission online monitoring system based on the off-axis integral cavity spectrum technology according to claim 1, wherein: the flue gas analyzer adopts TDLAS and OA-ICOS technology, and is provided with a sampling pump and a drainage system.