API Plan 23

Description;

API Plan 23 is an engineered seal flush arrangement that circulates process fluid from the seal chamber through an internal pumping ring, passes it through a heat exchanger, and returns the cooled fluid back to the seal chamber.

 

This localized closed-loop circulation reduces heat load at the seal faces while limiting direct mixing between hot pumpage and cooled seal chamber fluid.

 

The system is particularly suited for hot water, boiler feed water, hot hydrocarbons, and clean non-polymerizing fluids where vapor pressure margin, lubricity, and thermal stability are critical. Compared with direct-discharge cooling arrangements, Plan 23 provides efficient seal cooling with reduced cooler duty, lower cooling water demand, and reduced risk of heat exchanger fouling.

 

Key Features;

· Improves vapor pressure margin and helps reduce flashing risk at the seal faces.

· Compact cooler duty reduces heat exchanger size and cooling water consumption.

· Enhances hot water lubricity and seal face film stability in high-temperature service.

· Vent and drain provisions support commissioning, air removal, and safe maintenance.

· Closed-loop recirculation using an internal pumping ring for controlled seal chamber cooling.

· Recommended with close-clearance throat or restriction bushing to reduce hot product mixing.

· Heat exchanger removes localized seal heat without continuously cooling the full process stream.

 

Service Overview;

Parameter Value

Equipment Centrifugal pumps with single mechanical seals

Fluid Hot hydrocarbons, boiler feed water, hot water, clean non-polymerizing fluids

Service Nature High-temperature, hot/volatile, clean process fluid service

Operating Mode Closed-loop seal chamber recirculation through a heat exchanger

Typical Arrangement API Plan 23 with pumping ring, cooler, temperature indicator, vent, drain, and optional quench

 

Specifications

Item Min Max Typical/Notes

Size On Request On Request Selected to suit seal size, gland connections, pump geometry, and circulation flow

Pressure — 62 bar (899 psi) System pressure rating as per supplied Plan 23 data

Temp Ambient / process-dependent +180°C (+356°F) Maximum listed service temperature; cooler duty depends on seal heat load

Speed On Request On Request Governed by mechanical seal design, pumping ring geometry, shaft speed, and circulation requirement

Heat Removal

Capacity — 10.5 kW (35,826 BTU/hr) Based on the supplied Plan 23 specification

Cooling

Medium — On Request Typically, cooling water is passed through a shell/coil heat exchanger

 

Materials;

Component Standard Material Optional Material Comment

Heat Exchanger

Coil SS 316 Duplex SS / Hastelloy / Titanium Selected for process compatibility and chloride/corrosion exposure

Heat Exchanger

Shell Carbon Steel / Stainless Steel SS 316 / Duplex SS Based on the cooling water quality and the site metallurgy standard

Piping & Fittings SS 316 CS / SS 304 / Alloy materials SS 316 preferred for hot water and hydrocarbon service

Pumping Ring Seal OEM standard material SS 316 / Duplex SS / Alloy materials Geometry must match the seal chamber circulation requirement

Instrumentation Temperature Indicator Temperature Transmitter / Switch Used for monitoring the cooler outlet or seal chamber loop temperature

Vent & Drain

Valves SS 316 / CS Alloy construction Normally closed; required for commissioning and maintenance

Applications;

· Clean, non-polymerizing chemical process fluids.

· Hot water circulation pumps in thermal/process systems.

· Hot hydrocarbon pumps in refinery and petrochemical service.

· Boiler feed water pumps in power generation and utility service.

· High-temperature pump services requiring improved vapor margin.

· Single mechanical seal installations with localized seal chamber cooling.

· Services were reduced cooling water usage and lower heat exchanger fouling are required.

 

Operating Limits;

Parameter Value

Pressure Up to 62 bar (899 psi)

Temp Up to +180°C (+356°F)

Speed On Request; dependent on seal and pumping ring design

Size Range On Request; configured to suit seal chamber, gland, and connection size

Heat Removal Capacity Up to 10.5 kW (35,826 BTU/hr)

Recommended Service Hot water, boiler feed water, hot hydrocarbons, clean non-polymerizing fluids

 

Selection note;

Size range, allowable shaft speed, connection size, cooling water flow, and final metallurgy should be verified against the pump datasheet, seal chamber dimensions, API 682 seal selection, and site cooling water quality before release for manufacture.