I would like to ask about the differences in starting up a conventional cold high/low temperature hydrogenation unit versus a hot high/low temperature unit

Conventional cold high and low-pressure hydrogenation units typically operate at low temperatures, removing impurities such as oxides and sulfides from the feedstock through hydrogenation reactions. The high-temperature separation device operates at high temperatures and is primarily used for separation and purification during cracking or reforming processes. In general, cold high and low temperature hydrogenation units are suitable for applications that require the removal of impurities at lower temperatures, while hot high and low temperature units are more appropriate for chemical reactions and separation processes at higher temperatures. The preparations before operation and the operational parameters also vary; for cold high- and low-pressure hydrogenation units, the focus is on how to carry out hydrogenation effectively at low temperatures while ensuring the proper functioning of the equipment, whereas hot high- and low-pressure units emphasize issues such as the equipment’s pressure resistance at high temperatures and the selection of appropriate materials. .

There are the following differences between conventional cold high/low temperature hydrogenation units and hot high/low temperature hydrogenation units during startup: 1. Temperature control: In cold high/low temperature hydrogenation units, the temperature must be increased gradually during startup to ensure uniform temperature across the catalyst bed and prevent localized overheating. High-temperature hydrogenation unit: A high temperature is required during operation to maintain such conditions and ensure catalyst activity. 2. Catalyst activation: In low-temperature hydroprocessing units, the catalyst needs to be gradually activated at low temperatures, usually through hydrogen reduction. High-temperature hydrogenation unit: The catalyst has been pre-activated at high temperature, and only maintaining this high temperature is required during operation. 3. Hydrogen supply: For cold high and low pressure hydrogenation units, the hydrogen supply must be increased gradually at startup to prevent too rapid reactions. High-temperature hydrogenation unit: A large amount of hydrogen is supplied during startup to maintain high-temperature reactions. 4. Pressure control in cold high and low-pressure hydrogenation units: The pressure must be increased gradually during startup to ensure system stability. High-temperature high-pressure hydrogenation unit: High pressure is required at startup to maintain the reaction conditions. 5. Feed of raw materials: In the cold high/low pressure hydrogenation unit, the feed of raw materials must be increased gradually at startup to prevent too rapid a reaction. High-temperature hydrogenation unit: During startup, a large amount of feedstock is supplied to maintain a high-temperature reaction. 6. Safety measures for low-temperature high-pressure hydrogenation units: Special attention must be paid to equipment protection and anti-freezing measures at low temperatures. High-temperature hydrogenation unit: Special attention must be paid to equipment protection and overheating prevention at high temperatures. 7. Operator training for low-temperature high-pressure hydrogenation units: Operators need to be familiar with low-temperature operation and the gradual temperature increase process. High-temperature hydrogenation unit: Operators need to be familiar with high-temperature operations and maintaining such conditions. 8. Equipment inspection: Low-temperature high-pressure hydrogenation unit: Before starting up, the low-temperature equipment must be inspected to ensure there is no freezing or blockage. High-temperature hydrogenation unit: Before starting up, the high-temperature equipment must be inspected to ensure there is no damage caused by overheating. 9. Environmental protection: Low-temperature hydrogenation units – attention must be paid to waste gas treatment at low temperatures to prevent contamination by condensates. High-temperature hydrogenation unit: Attention must be paid to the treatment of exhaust gases at high temperatures to prevent the emission of such gases. 10. Energy consumption: In the low- and high-temperature hydrogenation units, energy consumption is low at startup, and it increases gradually during the heating process. High-temperature hydrogenation unit: It consumes a high amount of energy during startup, and maintaining high temperatures requires continuous high energy consumption. These differences require operators to adopt appropriate startup strategies depending on the type of equipment, in order to ensure safe and efficient operation.

The biggest difference between cold high-pressure and hot high-pressure systems is energy efficiency; using a hot high-pressure system results in lower energy consumption. When starting up the system, it is necessary to take into account the relationship between temperature and pressure; this varies depending on the material used in the design. For example, in our case, the temperature must exceed 96°C when the pressure rises to 2.0 MPa. There aren’t many other differences – just a few variations in the processes involved