Thread Content
Has anyone worked on the design of a safety relief system for high-pressure hydrogen reactions? Could you explain the design approach? Why are generally two sets of relief pipelines installed in addition to the safety valves, and how should the capacity of each relief pipeline be determined?
This is the only information I could find online. Are there any books related to emergency pressure relief interlock systems? Please recommend some. For hydrogenation and hydrotreatment units, there is only a slow-pressure relief rate of 0.7 MPa/min. The emergency pressure relief of the hydrocracking unit includes a primary low-speed relief at 0.7 MPa/min and a secondary high-speed relief at 2.1 MPa/min. 2.3.1 Emergency pressure relief at 2.1 MPa/min ① Startup conditions The startup conditions for emergency pressure relief at 2.1 MPa/min are as follows: the temperature at any two points at the bottom of the reactor bed is greater than (the reactor’s design temperature minus 15°C); the circulating hydrogen compressor has stopped operating; the temperature at any point on the surface of the reactor is greater than (the reactor’s design temperature minus 15°C); the rate of temperature increase at any point at the bottom of the reactor bed is greater than 10°C/min. In case of other emergency situations in the plant (such as serious equipment failures or major fires), manual pressure relief is carried out. The automatic interlock activates the 2.1 MPa/min emergency pressure relief valve, or the operator can manually press the 2.1 MPa/min emergency pressure relief switch to open the valve. The safety level here is SIL 3; two emergency pressure relief valves that serve as a redundancy for each other are installed, with each valve equipped with two electromagnets connected in parallel. Reliability is emphasized here: the valve will open (for emergency venting) only if both solenoids are de-energized simultaneously. At the bottom of each bed layer in the reactor, there are multiple flexible thermocouples, which are evenly distributed across the reactor’s cross-sectional area – 1 detection point per approximately 1 m2. Different process packages (process patents) have varying configurations for these interlock temperatures and pressure relief valves; therefore, these venting conditions are provided for reference only. ②Pressure relief triggers interlocks in other equipment. An emergency pressure release at a rate of 2.1 MPa/min causes automatic interlock actions in related equipment, such as the shutdown of the hydrogen feed pump, the closure of the inlet isolation valve for the hydrogen feed pump’s hydraulic turbine, the shutdown of the main burner in the reactor heater (with the pilot burner remaining operational), the shutdown of the lean solvent pump, the closure of the inlet isolation valve and control valve for the lean solvent pump’s hydraulic turbine, the shutdown of the feed water pump, and the shutdown of the fresh hydrogen compressor. 2.3.2 Emergency pressure relief at 0.7 MPa/min The condition for initiating emergency pressure relief at 0.7 MPa/min is a manual initiation of the pressure relief process. The operator manually determines whether to activate an emergency pressure relief at a rate of 0.7 MPa/min, based on the severity of the hazard posed by an unexpected incident in the equipment; the cycle hydrogen compressor triggers automatic interlocked pressure relief when it stops operating. Manually press the 0.7MPa/min pressure relief switch to open the pressure relief valve, or the automatic interlock will activate the 0.7MPa/min emergency pressure relief valve. When pressure is released manually at a rate of 0.7 MPa/min, it will trigger automatic interlock actions in the related equipment: the hydrogen feed pump stops operating; the inlet isolation valve of the hydrogen feed pump’s hydraulic turbine is closed; the main burner of the reactor heater is turned off (while the pilot burner remains lit); the lean solvent pump stops working; the inlet isolation valve and control valve of the lean solvent pump’s hydraulic turbine are closed; and the fresh hydrogen compressor is set to a “zero” load. When automatic pressure relief at 0.7 MPa/min occurs, the following automatic interlock actions will be triggered: the hydrogen feed pump stops; the inlet isolation valve of the hydrogen feed pump’s hydraulic turbine is closed; the main burner of the reactor heater is shut off (the pilot burner remains on); and the fresh hydrogen compressor is set to a \"zero\" load.