Abstract
Выполнены расчеты по определению времени истечения водорода и смеси водорода с углекислотой из баллонов емкостью 0,04 м3 при различном начальном давлении газа через отверстия различного размера. Выявлены закономерности влияния различных параметров на время истечения газов. Показано, что при некоторых условиях можно избежать давления взрыва газовой смеси свыше 5 кПа в случае разгерметизации баллона с газом. When determining the room category by explosion and fire hazard, it is assumed that all the contents of the device, cylinder or other equipment completely go into the room, mixed with air, then the mixture explodes. Such a scenario is found the most dangerous. If the room is equipped with emergency ventilation activated by a signal from a fast-acting gas analyser, it is allowed to reduce the mass of flammable gas or vapour when calculating the explosion pressure. When gas in high pressure equipment enters the room, the time of entry depends on the gas quantity, pressure and other properties of the gas. The regulatory documentation for fire safety does not provide recommendations on calculating the gas discharge time from the equipment of the final volume, accompanied by pressure decrease. The purpose of this work is to estimate the gas discharge time from industrial cylinders with a capacity of 0.04 m3 depending on various factors. The task of the work is to calculate the K coefficient in the formula for determining the required air exchange rate of emergency ventilation. To solve this problem, there is considered the discharge of several combustible gases from cylinders with a volume of 0.04 m3 through holes of different diameters at different values of initial gas pressure. It is shown that when hydrogen flows out of a cylinder with an initial pressure of 20 MPa through a hole with a diameter of 4 mm, which corresponds to the full opening of the valve, the discharge time is 26 seconds, and when discharging under the same conditions through a hole with a diameter of 1 mm, the discharge time increases up to 346 seconds. In order to determine the possibility of protecting a room with hydrogen cylinders from an explosion of a hydrogen-air mixture, there were made calculations of explosion pressures values depending on the volume of the room. There are established conditions for the use of emergency ventilation to ensure explosion safety in an accident with a gas cylinder. In order to reduce the explosion pressure for this room to 5 kPa, it is necessary to increase the discharge time up to 300 s (5 minutes). Two ways to increase the flow time are considered: reducing the size of the hole (by inserting a washer into the cylinder valve) and preliminary dilution of combustible gas with incombustible gas when filling the cylinder. It is possible to use both methods at the same time to increase the gas discharge time from the cylinder.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
