Project Background

Cooperation Background

Against the backdrop of promoting clean and efficient utilization of coal and optimizing the transformation of energy structure in China, coal based synthetic oil, as an important path for coal conversion, has become a focus of industry attention in terms of fine monitoring and energy efficiency improvement of its production process. As a major coal producing province, Shanxi actively lays out the coal chemical industry based on its resource advantages, and focuses on promoting modern coal chemical projects such as coal to oil to improve quality and efficiency. Especially for synthetic oil plants using Luqi furnace gasification technology, real-time and accurate monitoring of outlet gas composition is directly related to gasification efficiency, synthetic oil yield, and safe and stable operation of the plant.

The crude synthesis gas produced during the gasification process of the Lurgi furnace has characteristics such as high temperature, high pressure, high tar, high dust, and high humidity, especially with significantly higher tar content than other gasification technologies, posing a severe challenge to online gas analysis systems. Traditional analytical equipment faces technical bottlenecks such as blocked sampling pipelines, sensor contamination, and interference with measurement principles, resulting in delayed monitoring data, insufficient accuracy, and even affecting production continuity due to frequent equipment failures. Therefore, breaking through the technical barriers of online gas monitoring under harsh working conditions and achieving real-time, accurate, and continuous analysis of synthesis gas components has become a key link in improving the operation level of coal based synthetic oil plants, ensuring safety production, and reducing material and energy consumption.

Project Introduction

The user of this project is a large state-owned coal chemical enterprise in Shanxi, with core products covering coal to oil, urea, liquid ammonia, etc. The Qiluqi furnace gasification device uses crushed coal as raw material, which is gasified with steam and oxygen to produce crude synthesis gas rich in carbon monoxide and hydrogen, as the key raw material gas for subsequent Fischer Tropsch synthesis oil production. The device has been operating for more than ten years and has been limited by harsh conditions such as high tar, high temperature, and high pressure. It has not been able to establish an effective online gas analysis system, mainly relying on manual sampling and offline analysis. The data lag is severe and cannot guide process adjustments in real time.

In the early stage, users tried solutions from multiple analysis equipment manufacturers, but none of them were able to operate stably for a long time due to their inability to adapt to on-site working conditions. To solve the above problems, the user initiated a process gas monitoring system upgrade project. After multiple investigations and technical comparisons, the in-situ laser Raman spectroscopy analysis solution of Sifang Instrument was finally selected. It is worth emphasizing that the LRGA-3200EX successfully put into operation in this project is the first in-situ laser Raman spectroscopy gas analyzer in China's coal chemical industry to achieve engineering applications. After being installed and put into use at the outlet of the Lurgi furnace, it has achieved continuous, automatic, and synchronous online monitoring of various gas components in synthesis gas, marking an important breakthrough in the application of domestic gas analysis instruments in complex coal chemical conditions.

Product Prototype

In situ laser Raman spectroscopy gas analyzer LRGA-3200EX

Main parameters

project implementation

Technical Solution

The in-situ laser Raman spectroscopy gas analyzer provided by our company for this project is designed specifically for complex working conditions such as high temperature, high pressure, and high tar. It can accurately measure various components in synthesis gas without interference from moisture in the background gas. Its core advantage lies in its strong scalability and support for flexible "one to many" configurations. A set of analysis hosts can simultaneously connect multiple front-end Raman probes, achieving distributed synchronous monitoring of several key points in the production process, providing a solid technical foundation for achieving comprehensive gas monitoring of the entire device and process in the future. The project has configured the "one driven two" mode according to user requirements.

The system consists of four parts: sampling unit, preprocessing unit, control unit, and analysis unit. It automatically completes pipeline sampling and other operations, achieving 24-hour unmanned operation. While significantly reducing manual load, it ensures the long-term stability, accuracy, and continuous operation of the system.

As a successful in-situ laser Raman spectroscopy gas analyzer applied in the coal chemical industry, its in-situ measurement method can perform continuous, online, and non-destructive analysis of various gas components. By placing the Raman probe in front, the instrument does not need to directly contact the sample gas, which not only reduces the maintenance workload of the sampling device and analytical instrument, but also greatly improves the response speed. In response to the problem of high tar content and easy condensation in the synthesis gas of the Lurgi furnace, the probe sampling unit innovatively adopts a design combining water cooling and steam blowing, effectively preventing tar adhesion and pipeline blockage. The preprocessing unit is equipped with multi-stage filtration and pressure reduction and stabilization devices, which efficiently remove dust, liquid water, and ammonium salt crystals while maintaining the original composition of the sample gas, ensuring that the gas entering the analyzer is clean and stable.

The project site requires the monitoring system to operate stably under high temperature of 200 ℃ and high pressure of 4MPa, and accurately measure key components including H2, O2, CO, CO2, CH4, H2S, and N2. Compared with traditional gas chromatography technology, laser Raman analyzer does not require carrier gas and frequent calibration, has a fast response speed (T90 ≤ 10 seconds), and can capture process fluctuations in real time, providing real-time data support for adjusting the oxygen steam ratio of gasifier and regulating the Fischer Tropsch synthesis reactor. The successful application of this scheme has pioneered the engineering application of domestic in-situ laser Raman technology in the coal chemical industry, providing a replicable domestic monitoring path for the industry.

Solution Value

The implementation of this technical solution has enabled more effective management and adjustment of the process of coal based synthetic oil, thereby achieving safety control and economic benefits improvement.

In terms of safety monitoring, real-time monitoring of O2 concentration can promptly detect the risk of oxygen enrichment in gasification furnaces and prevent safety accidents from occurring; At the same time, continuous monitoring of harmful gases such as H2S provides a guarantee for environmental and personnel safety.

In terms of process optimization and quality improvement, by monitoring the concentration changes of key components such as H2, CO, CO2, CH4 in real time, operators can adjust the feed gas ratio of the gasifier, control the reaction temperature, optimize the conditions of Fischer Tropsch synthesis, and thus improve carbon conversion rate and oil yield. According to user feedback, after the system was put into operation, the raw material coal consumption significantly decreased, the average operating time of the equipment exceeded 30 days, and the operation and maintenance costs significantly decreased.

The successful implementation of this project not only solves the industry problem of online gas monitoring under harsh working conditions, but also serves as a milestone in promoting the industry's technological upgrading and domestic substitution process as an in-situ laser Raman analysis system successfully put into use in the coal chemical industry.

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