Device and method for testing the explosion characteristics of combustible gas at ultra-low temperature

Abstract

The invention relates to a device and a method for testing the explosion properties of flammable gases at ultralow temperature. The device comprises a refrigerating device, an explosion vessel with a length-diameter ratio of 3 to 1 is arranged in an inner cavity of the refrigerating device, a gap is formed between the explosion vessel and the inner cavity of the refrigerating device, and a heat conducting material by which the temperatures of the explosion vessel and gas in the explosion vessel are reduced to an experimental temperature is added in the gap; the top of the explosion vessel is sealed by a blind flange, two ignition electrodes connected with an ignition energy console are arranged in the explosion vessel, the bottom of the explosion vessel is provided with a liquid outlet for implementing the cleaning of deposited carbon in the explosion vessel, and a strain gage for carrying out real-time monitoring on heat stress produced in the process of explosion is attached to the inner wall of the explosion vessel; and the blind flange is provided with a temperature sensor, a pressure sensor, a gas inlet and a gas outlet, and the gas inlet and the gas outlet are communicated with the inside of the explosion vessel. The device disclosed by the invention can be used for eliminating the trouble that the application amount of liquid nitrogen in liquid-nitrogen refrigerating is huge, and avoiding the occurrence of risks and ultra-high heat stress caused by the rapid evaporation of liquid nitrogen due to heat produced by explosion; and the device is high in refrigeration efficiency, and can meet the requirements on minimum ignition energy and explosion limit tests.

Description

technical field [0001] The invention belongs to the technical field of industrial production safety, and in particular relates to a testing device and method for researching characteristics such as the explosion limit of flammable gas in an ultra-low temperature environment. Background technique [0002] my country has abundant reserves of coalbed methane resources and great potential for development. The coalbed methane currently mined mostly contains air components such as nitrogen and oxygen, which has the risk of explosion. Coalbed methane liquefaction is one of the main application areas of coalbed methane. In the purification stage of the coalbed methane liquefaction process, in the rectification tower, with the gradual liquefaction and purification of methane, the content of oxygen and nitrogen at the top of the rectification tower gradually increases, and the content of methane is relatively low. Therefore, under the "low temperature and high pressure" working condi...

AI Technical Summary

Problems solved by technology

Its disadvantages are as follows: ①The refrigeration technology uses liquid nitrogen refrigeration. Liquid nitrogen is easy to volatilize in the atmosphere, which makes the amount of liquid nitrogen huge and uneconomical; the explosion of combustible gas generates a lot of heat, which may cause the liquid nitrogen in the interlayer to Rapid vaporization poses a physical explosion hazard

The so-called thermal stress is explained as: the explosion of the gas in the explosion tank is completed instantly, and the explosion generates a large amount of heat, which is quickly transmitted to the inner wall of the container through heat convection and heat radiation, so that the temperature of the inner wall of the container rises rapidly, and the outer wall of the container is still at a lower temperature. There is a large temperature gradient on the inner and outer walls, resulting in a large thermal stress on the container wall, which can be as high as 1000MPa, which is far greater than the allowable stress of the material, making the container invalid and causing a great safety hazard

③ The minimum ignition energy of combustible gas cannot be accurately measured, especially the determination of sensitive conditions; the geometric dimensions of the explosion vessel and the criteria for judging the occurrence of explosion have not been studied, and more accurate parameters such as the explosion limit cannot be obtained

④ After multiple explosions, a large amount of carbon deposits will be generated on the inner wall of the container and the ignition electrode. The device used must open the container cover for internal cleaning, which is time-consuming and laborious

⑤ The detailed process of the explosion characteristic test is not given

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