F-P optical signal enhancement-based sensing device for measuring online gas content in petrochemical hydrogen-carrying pipe

Abstract

The invention provides an optical enhancing cavity and sensing device for measuring online gas content in a petrochemical hydrogen-carrying pipe. The sensing device comprises a sample cell provided with a gas inlet and a gas outlet; left and right ends of the sample cell are provided with a first reflector and a second reflector respectively, wherein both the first reflector and the second reflector comprise a spherical face, the middle of which is a circular plane; the first reflector is provided with a laser inlet for incoming of laser; the side of the sample cell is provided with a window glass plate connected with a Raman signal collecting unit for transmitting light. The optical enhancing cavity is composed of special reflectors, a double F-P cavity structure of the spherical face and circular plane is formed, laser power is greatly enhanced, which is unreachable for other devices, Raman signal light is enhanced by multiple orders of magnitude so that sensitivity and precision are very high, all-optical measurement is achieved on the petrochemical pipe, intrinsic safety is achieved, and online real-time measurement is also achieved.

Description

technical field [0001] The invention relates to the field of petrochemical gas content measurement, in particular to a sensor device for on-line gas content measurement of petrochemical hydrogen-carrying pipelines based on F-P optical signal enhancement. Background technique [0002] The hydrogen-carrying process is widely used in the petrochemical industry. Under the conditions of appropriate temperature, hydrogen concentration and air pressure, it can generate chemical products such as hydrocarbons or alcohols with a certain molecular weight. Ethylene hydrogen is used in hydrocracking units and wax oil hydrogenation units. If the purity of ethylene hydrogen decreases, the partial pressure of hydrogen in the system of the above-mentioned hydrogenation units will be reduced, which is not conducive to the hydrogenation reaction and will affect product quality. In order to maintain sufficient partial pressure of hydrogen, the hydrogenation unit also needs to discharge gas with...

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Problems solved by technology

If the purity of ethylene hydrogen is reduced, the partial pressure of hydrogen in the system of the above-mentioned hydrogenation unit will be reduced, which will be unfavorable to the hydrogenation reaction and affect the product quality

[0005] (3) CO and CO 2 Under the condition of hydrogen, a methanation reaction will occur, and a large amount of heat will be released in the catalyst bed, which will cause the bed to overheat and affect the product quality.

[0011] CN1584555A discloses a quick measuring instrument for petroleum product quality based on low-resolution Raman spectroscopy. This device is mainly used to detect the quality of petroleum oil products. It is characterized by low cost, small size, and portability, but its resolution is not high. Raman scattering enhancement system is not designed, not suitable for gas detection in petrochemical industry

[0012] CN1645106A discloses a Raman technology-based dissolved gas analysis device in power transformer oil. The device uses a near-concentric cavity optical system as a Raman scattering enhancement device, which improves sensitivity compared to other devices, but the device uses lasers, samples The pool and the optical system are fixed on a mounting plate, which will inevitably use the power supply, which is not conducive to installation on the site of flammable and explosive gas pipelines such as ethylene hydrogen in the petrochemical industry, and the strengthening effect of this optical system is limited

[0013] At present, the Raman online monitoring measurement system applied to ethylene hydrogen and other flammable and explosive gases in the petrochemical industry is still relatively rare in China. There is no need to use electricity and other equipment that may cause potential safety hazards, and at the same time, the airtightness of the sample cell must also be considered

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