High temperature solenoid valves are key fluid control components in the chemical industry, widely used in applications involving high-temperature media, high-temperature processes, or high-temperature environments. Its design needs to take into account temperature resistance, sealing, safety, and reliability to meet the stringent requirements of continuous operation and intrinsic safety in chemical production.
Reactor temperature control system
Characteristics of working conditions: The reaction temperature often reaches 200-400 ℃, and some strong exothermic reactions such as polymerization, esterification, and nitration may even be higher.
Application method:
Control the entry of thermal oil, steam, or high-temperature nitrogen into the jacket/coil to achieve heating;
Quickly cut off the heat source in emergency situations to prevent "overheating" accidents.
Technical Requirements:
The valve body material is mostly 316L stainless steel, Inconel 625 or high-temperature alloy;
The sealing material adopts metal sealing (such as corrugated pipe sealing) or high-temperature fluororubber (such as Kalrez);
Fast action response (<100 ms), with Ex explosion-proof certification (such as Ex d IIC T6).
Thermal oil system (heat medium system)
Typical media: biphenyl ether mixture (such as Dowtherm A), mineral oil, synthetic thermal oil.
Working temperature: 250-350 ℃, system pressure is usually 0.6-2.5 MPa.
Function:
Control the flow of heat transfer oil to different reaction units;
Implement zone heating or shutdown insulation.
Special Design:
Adopting a heat sink structure or external coils to avoid coil overheating and failure;
Steam system (high-pressure saturated/superheated steam)
Application Scenario:
Steam heating, distillation, drying, sterilization;
Pipeline blowing and equipment cleaning.
Parameter Range:
Saturated steam: 180-250 ℃, 1.0-4.0 MPa;
Overheated steam: can reach above 450 ℃.
Technical challenges:
High temperature leads to aging and failure of ordinary rubber seals;
Condensed water can easily cause "water hammer" impact.
Solution:
Using all metal sealing and piston structure;
Equipped with a drain valve group or pre filter to extend its lifespan.
High temperature gas transportation and protection system
Examples of media: nitrogen, hydrogen, inert gases, cracking gases, etc.
Purpose:
Inert atmosphere protection for reaction kettle;
High temperature catalyst regeneration (such as reforming units);
Hydrogen refueling and circulation (such as hydrogenation refining).
Key requirements:
Valves must pass ISO 15848-1 micro leakage test (Class V/VI);
Resistant to hydrogen embrittlement in a 300 ℃+hydrogen environment (using low-carbon stainless steel or nickel based alloys).
Incineration and exhaust gas treatment system
Operating conditions: The outlet flue gas temperature of RTO (Regenerative Thermal Oxidizer) and catalytic combustion device often reaches 300-600 ℃.
Function:
Control the on/off of combustion air or fuel gas;
Emergency shutdown to prevent tempering or overheating.
Design points:
Valve body with insulation layer or air-cooled structure;
The coil adopts high temperature insulation level (H level, 180 ℃).
Fine Chemicals and Synthesis of New Materials
Typical processes: synthesis of lithium battery electrolyte, preparation of polyimide (PI) film, synthesis of organic silicon monomer.
Requirement characteristics:
The requirements for cleanliness, pollution-free, and high-precision control are extremely high;
Some processes require long-term stable operation at 200-300 ℃.
Trend:
Adopting bellows sealed solenoid valve to achieve zero external leakage;
Integrated position feedback and flow regulation module, supporting DCS linkage.