The definition of online monitoring system for oil and gas recovery in GB20952-2007 Emission Standard For Air Pollutants Of Gas Stations is: Online monitoring system is used for checking three indicators in the process of oil and gas recovery are normal or not, the three indicators are gas-liquid ratio of the oil gun, the tightness of the underground pipeline system and the pressure of the oil-gas recovery pipeline. System would remind the operator when abnormal issues are found, and take corresponding measures and be able to record, store, process and transmit monitoring data.

1、 System composition

The system is generally composed of sensors, electrical measurement subsystem, data remote transmission system and data centralized management software platform. Due to different practical application technology, the composition of the system is also different.

2、 How it works

Through the measurement instrument, data acquisition and transmission equipment and data processing equipment installed on the site, the key parameters (recovery gas volume, oil filling volume, oil tank and pipeline pressure) of oil and gas recovery system operation are analyzed for measurement, analysis and transmission, and some other indicators such as calculation of A/L, tightness, liquid resistance are monitored real-time by those equipment.

Specifically: measuring the flow of recovered oil and gas when the system in  working status by the flowmeter, then generate pulse signal, transmit to data acquisition module, convert to cumulative flow, at the same time, data acquisition module automatically calculates the pumping time of vacuum pump, and uses volume and time to calculate the average speed of return gas.

In addition, the data acquisition module synchronously collects the oil filling volume pulse signal, calculates the corresponding oil filling volume, the ratio of the return gas volume to the oil filling volume, i.e. A/L index; And measures the return gas pipeline pressure by the pressure transmitter; the output analog signal are converted by the data acquisition module. calculation for the liquid resistance index of the pipeline and the tightness index of the tank and the pipeline are achieved according to the regular fluctuation range of the pressure value in the working process of the system and the decrease speed ratio and value during standby state of the oil and gas recovery system.

The gas station monitoring center also can be integral part of the on-line monitoring system of the Municipal Bureau. The system can be integrated with the Municipal Bureau platform to realize the interconnection of data and process; the central-end background of the system support data sharing with the Municipal Bureau platform, and transform the networking mode of data interface to realize the integration and sharing of data through multiple ways of access.

One of our customer is the solution provider of oil and gas recovery automatic monitoring system, Touch Think industrial mini PC with X86-based platform is embedded into the system as upper-level computer, it equipped industrial grade main board and fan-free design for heat-dissipation ensure its 7/24 long-time operation. In addition, our industrial touch screen monitors also embedded to oil filling machine, The industrial display support sunlight readable in oil station environment, offering high quality display image for operators and customers, IP65 dust-proof and water proof for its front panel.

Solution Overview

This oil and gas recovery automatic monitoring system solution (VOCs monitoring solution) can be used for monitoring non-methane total hydrocarbons in the exhaust outlet of the oil and gas recovery device of oil depots. This solution uses the independently developed online gas chromatograph (GC-FID) as the core. The pipeline is heat-tracing and explosion-proof during the whole process. The entire process is inertized without adsorption. It is safe and reliable. It is suitable for various industrial environments. The measurement results are accurate and real-time and with low cost. It meets national and industry standards for volatile organic compounds monitoring requirements.

Due to the content of non-methane total hydrocarbons in the oil depot recovery system is very high, the gas chromatograph is used for monitoring the ultra-high levels of non-methane total hydrocarbons, which fully meets the needs of oil depot exhaust emissions monitoring. The entire system is explosion-proof and fully meets the explosion-proof requirements of oil depots.

Solution principle 

The sample gas passes through multi-stage filtration and dust removal and high-temperature heat tracing, enters the online gas chromatograph, uses the quantitative loop for quantification, and switches into the chromatographic column through the valve, separates different target pollutants and sequentially enters the FID detector, test its concentration and combining temperature and pressure flow condition data, output the result of the emission data to the upper computer system, and upload it to the relevant department through the data acquisition instrument.

Solution Features

1. The sampling pipeline is made of inert and corrosion-resistant material, and support high-temperature heat tracing during whole process. No adsorption, no condensation.

2. Multi-level precise filtration to remove particles from the gas sample.

3. With automatic purging function, it support automatically remove the dust on the surface of filter element and prolong the service life of filter element.

4. Support automatic calibration function, realize unattended operation.

5. Automatic gas cut-off and start alarm function in case of leakage of hydrogen and other dangerous gases.

6. The sampling signal is connected to the upper-level computer, wiring layout of the system is simple, easy for installation and maintenance.

7. The system supports multiple signal outputs such as temperature & pressure flow and target concentration, and it also can be connected to DCs.

Advantage

The environmental protection department will realize the supervision and monitoring of the stable operation of the oil and gas recovery system through this system, which avoid the behavior of exceeding the standard emission caused by the non subjective in the gas station. At the same time, it improves the environmental management efficiency of the gas station, increases the oil and gas recovery volume, improves the economic efficiency and promotes environmental protection.