Valves and flow equipment for the organic chemicals industry

Organic chemical plants operate with solvent, organic intermediate, resin, alcohol, hydrocarbon, additive, petrochemical product, steam, thermal oil, chilled water, glycol, nitrogen, compressed air and auxiliary fluid lines. Valve selection is based on fluid chemistry, temperature, pressure, viscosity, volatility, flammability and the sealing requirements of each line.

Organic synthesis, mixing, distillation, condensation, storage, transfer and dosing processes require a defined function for each valve. Correct sizing helps limit excessive flow velocity, pressure losses, flow fluctuations and the risk of external leakage from stems, flanges, gaskets and connection points.

Typical applications

• Solvent, alcohol, ketone, ester, hydrocarbon and organic mixture lines.
• Transfer and dosing of organic intermediates, additives, resins and raw materials.
• Steam networks for heating reactors, heat exchangers, tanks and pipework.
• Thermal oil circuits for controlled process heating.
• Chilled water, glycol and cooling water lines for condensers and heat exchangers.
• Nitrogen systems for purging, blanketing, inerting and oxygen displacement.
• Venting, relief, draining, sampling and bypass lines.
• Auxiliary compressed air networks for pneumatic actuators and control instruments.

Equipment selection criteria

• Compatibility of body, seat, stem, gasket and packing materials with the organic fluid.
• Operating pressure, design pressure and valve differential pressure.
• Operating temperature, cleaning temperature and variations during start-up or shutdown.
• Viscosity, density, volatility, vapour pressure and risk of vapour or gas pocket formation.
• Fluid flammability and requirements for grounding, ventilation and section isolation.
• Required flow rate and allowable pressure drop.
• Isolation, control, non-return, relief or overpressure protection function.
• Seat, stem and connection tightness requirements.
• Actuation method: manual, pneumatic, electric or self-acting.
• Connection to PLC, DCS, SCADA or process safety system.

Indicative equipment

• Isolation valves for solvents, organic chemicals, steam, water, nitrogen and auxiliary fluids.
• Control valves for flow, pressure, temperature or level regulation.
• Bellows-sealed valves or special stem sealing arrangements for reduced external leakage.
• Pressure reducing valves and pressure regulators for steam, nitrogen, air and auxiliary gases.
• Check valves for protection of pumps, compressors and dosing systems.
• Safety and relief valves for vessels, reactors, heat exchangers and pipework.
• Steam traps and condensate equipment for steam lines.
• Line strainers for protection of control valves, pumps, nozzles and instruments.
• Pneumatic and electric actuators for remote or automatic operation.

For each application, the organic fluid composition, pressure, temperature, flow rate, viscosity, volatility, external leakage risk and valve function in the control system should be reviewed. These data define the valve type, nominal size, pressure class, construction materials, sealing arrangement and suitable actuation method.