The gas source pressure at the chemical site varies depending on the specific application scenario and process requirements, the common pressure range covers low to medium pressure, specifically including instrument air pressure (0.4-0.7MPa), common industrial compressed air pressure (0.6-1.0MPa), chemical steam pressure grade (low pressure ≤ 1.57MPa, medium pressure 1.58-3.82MPa) and special process gas source pressure (up to 8.5MPa and above). The following is a detailed analysis:
1. instrument air pressure
instrument air is the gas source used to drive pneumatic actuators (such as pneumatic valves and pneumatic pumps) in chemical sites, and its pressure is usually required to be 0.4-0.7MPa (gauge pressure). This pressure range can not only meet the driving needs of most pneumatic equipment, but also avoid equipment damage or increased energy consumption due to high pressure. For example, the static air consumption of the pneumatic valve is generally 20L/h, and it can operate stably under the pressure of 0.4-0.7MPa.
2. general industrial compressed air pressure
in chemical production, compressed air is also widely used in metal processing, plastic products production, material transportation and other links. At this time, the pressure of compressed air is usually 0.6-1.0MPa between. For example:
- metal processing sandblasting, cutting and other processes require 0.7-1.0MPa compressed air to provide sufficient impact force;
- plastic Products Production: Blow molding, injection molding and other processes require 0.6-0.8MPa compressed air to drive the mold or auxiliary molding.
3. chemical steam pressure grade
the steam system at the chemical site is divided into multiple levels according to pressure, and different levels correspond to different application scenarios:
- low pressure steam: Pressure ≤ 1.57MPa, mainly used for heating, heat preservation or driving low-pressure steam turbine;
- medium pressure steam: Pressure 1.58-3.82MPa, common in chemical reactor heating, distillation tower reboiler and other scenarios;
- secondary HP/HP Steam: Pressure 3.83-13.7MPa, used in high temperature and high pressure reaction process of large chemical plants (such as synthetic ammonia and methanol production).
Typical case:
- the petrochemical park is dominated by 3.82MPa superheated steam to meet the high temperature reaction requirements;
- ordinary industrial parks (such as textile and food industries) are dominated by low-pressure steam ≤ 1.0MPa, which is used for production heating or disinfection.
4. special process gas source pressure
some chemical processes (such as gasification, synthesis) require higher pressure gas source:
- gasification process: The pressure of coal slurry and oxygen is provided by a pump. Common pressure levels include 2.7MPa, 4.0MPa, 6.5MPa, 8.5MPa, etc. High pressure can improve the gasification strength and reduce the power consumption of subsequent gas compression. For example, a single gasifier with a diameter of 3.2m can produce 760 tons of ammonia per day under a pressure of 4.0MPa;
- synthetic process: Syngas compression, ammonia synthesis and other links need a high-pressure gas source of 6.5-8.5MPa to ensure reaction efficiency.
Core Principles of 5. Pressure Selection
the selection of gas source pressure at the chemical site needs to integrate the following factors:
- process requirements: Determine the minimum pressure requirement according to the reaction temperature, material nature and equipment type;
- economy: High-pressure gas source requires higher energy consumption and equipment investment, and needs to balance costs and benefits;
- security: Avoid the risk of leakage or explosion caused by over-pressure operation of the equipment due to over-pressure;
- standard Compliance comply with relevant national standards (such as industrial compressed air pressure range 0.6-0.8MPa) and industry specifications.
