Nitrogen for hydrogenation unit accidents
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Hello everyone, the operating pressure of the hydrogenation unit is 16.0 MPa. An emergency nitrogen tank is installed; what should be the typical pressure setting for this emergency nitrogen tank? Thank you!
Simply put, the purpose of the accident nitrogen tank is to supply nitrogen to the system promptly in the event of an accident in the hydrogenation system, thereby serving to displace air, reduce temperature, and maintain the flow of the medium in the bed. Therefore, the pressure set for the nitrogen tank must be higher than the design pressure of the hydrogenation system. As for pressure, pipe diameter, and flow rate settings, they should be determined through process design calculations; there should be no approximation or rough handling.
During an accident, nitrogen is introduced into the system to serve the purposes of displacement, cooling, and maintaining flow of the medium in the bed. Nitrogen is injected when the pressure in the system drops to a certain level; generally, at what pressure level is nitrogen introduced? So, the pressure of the high-pressure nitrogen tank needs to be taken into account.
Using 4.0 MPa nitrogen gas after nitrogen vaporization
I have been in contact with five or six plants that have a total of over a dozen hydrogenation units, and I have never seen any of them equipped with emergency nitrogen tanks. Generally, such plants have air separation units that produce nitrogen, which is then pressurized to 4.0 Mpa and distributed throughout the plant’s nitrogen pipeline network. In the event of an emergency in a hydrogenation unit, when the pressure in the reaction system drops below 4.0 Mpa, 4.0 Mpa nitrogen is introduced at the outlet of the recycle hydrogen compressor to continue the process of displacement and cooling. The reason you have installed accident nitrogen tanks might be 1: during an accident, the amount of nitrogen available is limited, so tanks are installed to store a reserve supply.
Emergency nitrogen refers to the nitrogen used in emergency situations. The purpose of installing buffer tanks is to enable a large supply of nitrogen to be provided promptly and in large quantities, without causing excessive fluctuations in the pressure within the system’s piping network. Nitrogen is generally available in low-pressure, medium-pressure, and high-pressure forms. In emergency situations, nitrogen can only be introduced into the system once the system pressure has dropped to a certain level; the pressure of the nitrogen cannot be higher than that of the system when it is operating normally!
There is no need for an accident nitrogen tank; a 6.0 liquid nitrogen pump plus vaporizer is sufficient
Install a high-pressure nitrogen tank, or relieve pressure to the device’s existing medium-pressure nitrogen level, to ensure that nitrogen can flow into the system.