Staged Flash Purpose

Single-stage flash from high to low pressure wastes valuable components to vapor. Staged flashing through intermediate pressures recovers more liquid at each level. HP drum captures first vapor stage. LP drum removes remaining lights. Optimizes recovery versus vapor handling costs.

HP Flash Operation

High-pressure liquid from upstream reduces pressure to intermediate level typically 50-70% of inlet pressure. Dissolved light ends vaporize. HP drum separates phases. Vapor routes to medium-pressure system. Partially degassed liquid flows to LP flash.

LP Flash Operation

Liquid from HP stage reduces to near-atmospheric or final process pressure. Additional light components vaporize. LP drum separates remaining vapor from liquid product. Final liquid achieves target composition. LP vapor handles separately from HP vapor.

Pressure Staging

Three-stage flash common in complex systems - HP, MP, LP. Each stage optimizes pressure balancing liquid recovery against vapor handling. Computer simulation determines optimal staging for specific application and economics.

Vessel Design

Vertical or horizontal drums with liquid inlet, vapor space for disengagement, mist eliminator, vapor and liquid outlets, level control. Each stage sized for respective flow and pressure. HP vessel heavier construction than LP.

Material Selection

Carbon steel for hydrocarbon service. Stainless steel for corrosive applications. Each vessel designed for operating pressure with safety margin. HP drum requires thicker walls and higher-grade materials.

Applications

Oil production multi-stage separation, refinery crude stabilization, gas plant NGL recovery, condensate processing, geothermal power plants, and any process benefiting from staged pressure reduction maximizing liquid recovery.

Vapor Recovery

HP flash vapor higher pressure enables compression or routing to medium-pressure systems. LP vapor near-atmospheric may flare or compress depending on economics. Staged vapor handling reduces overall compression costs versus single-stage.

Energy Integration

Flash cooling from pressure reduction provides refrigeration effect. Some systems integrate flash drums with refrigeration cycles. Pressure staging optimizes energy recovery from depressurization.

Level Control

Independent level instruments manage inventory in each drum. Controllers coordinate interstage flows. High-level protection prevents carryover. Automated operation optimizes overall separation train performance.

Performance Benefits

Maximizes liquid product recovery versus single-stage flash. Reduces compression costs through staged vapor handling. Improves product quality through selective light ends removal. Proven technology optimizing separation economics.

Construction Standards

Each vessel designed per ASME Section VIII for respective pressure. Materials suitable for service conditions. Relief protection per API standards. Complete system documentation with flash equilibrium calculations.

ERGIL HP/LP flash drums optimize multi-stage separation through sequential pressure reduction maximizing liquid recovery in oil, gas, and process applications.