LP & HP DOSING SYSTEM

SS LP & HP Dosing Systems (Skid-Mounted)

An LP (Low Pressure) & HP (High Pressure) Dosing System, typically skid-mounted, is a compact, pre-assembled package for dosing chemicals precisely into boiler feedwater or process streams. These systems are widely used in:.

• Boiler units (LP, IP, HP sections),
• Water treatment (WTP, STP, ETP),
• Oil & gas, sugar, and refinery industries.

LP vs. HP Systems:

• LP (Low Pressure): For feed water treatment, cooling water, general water conditioning where pressure is lower.
• HP (High Pressure): Specifically for boiler feedwater, often near the pump discharge, handling the higher forces to ensure chemicals mix effectively before entering the high-pressure boiler drum.



Components & Features

According to various manufacturers (e.g., Minimax, Shriram Associates):

• Solution Preparation Tank : single or multi-compartment, often paired with agitators for mixing.
• Dosing Pumps : plunger or diaphragm type, single or multiple units.
• Dosing Pumps : plunger or diaphragm type, single or multiple units.
• Instrumentation : pressure gauges, level gauges, switches, PRVs, sensors, VFDs, and interconnecting pipes and valves.
• Agitators & Valves : to ensure uniform chemical mixing and controlled dosing.
• Materials : typically stainless steel (SS 304 / 316), sometimes HDPE, PP, FRP coatings as per chemical compatibility.



Technical Specifications (Examples)

ENCON's HP / LP Skid Mounted Dosing Units

• Flow Rate: 0 to 10,000 LPH (simplex), up to 75,000 LPH (multiplex)
• Pressure: up to 500 kg/cm² (Head up to 5,000 m)
• Power: up to 30 HP motors; speeds of 1,000 3,000 RPM; voltage 220 V/280 V/415 V
• Materials: SS 304/316, PTFE, PP, PVDF, alloy variants including Hastelloy 20, Titanium, etc.
• Applications: boiler dosing, chemical mixing, RO, WTP/STP/ETP, oil & refinery, sugar industries
• Delivery: Skids typically measure : 6x6x10 ft, come with one-year warranties and all over India as well as abroad delivery.



Benefits:

• Corrosion & Scale Prevention: Extends equipment life.
• Efficiency: Maintains heat transfer, reducing fuel costs.
• Safety: Prevents catastrophic failures from blockages or corrosion.
• Automation: Sensors (pH, conductivity) and control panels optimize chemical usage



Functionality by Pressure Type

LP (Low Pressure) Systems

• Aim to control pH, remove oxygen, and prevent corrosion in water-steam cycles.
• Commonly use oxygen scavengers, corrosion inhibitors, or buffering chemicals.
• • A typical component layout: chemical tank - dosing pump -control panel - feedwater.

HP (High Pressure) Systems

• Designed for tougher conditions, such as high-pressure boiler sections.
• Often dose highly alkaline agents like trisodium phosphate to maintain pH and prevent scale or corrosion.
• Incorporate robust pumps and control systems for precision dosing under high pressure.

Specification Table

Feature	Specifications
Flow Rate	LP - up to 10,000 LPH; Multiplex up to 75,000 LPH
Pressure	LP ~10 kg/cm²; HP up to ~500 kg/cm² (Head up to 5,000 m)
Pumps	Plunger / Diaphragm, single or multiple units
Materials	SS 304 / 316, PTFE, PP, HDPE, FRP, Hastelloy-20, Titanium
Instrumentations	Level/pressure gauges, PRV, VFDs, sensors, level switches
Configurations	Skid-mounted with agitator, solution tank, piping, control systems
Applications	Boiler units (LP/IP/HP), WTP/STP/ETP, oil & gas, sugar, refinery
Control	Manual, Semi-automatic, or Fully automatic

Key Applications

• Boiler Water Treatment: The primary use, preventing mineral buildup (scaling) and corrosion in steam boilers by adding oxygen scavengers (like sodium sulfite) and pH boosters (like caustic soda).
• Cooling Towers: Controlling algae, bacteria, and scale in cooling water loops to maintain heat transfer efficiency.
• Reverse Osmosis (RO) Plants: Dosing anti-scalants to prevent membrane fouling and cleaning chemicals for maintenance.
• Wastewater Treatment: Adding coagulants, flocculants, or pH adjusters for effluent clarification.
• Process Dosing: In chemical, oil & gas, and food & beverage industries, where precise chemical addition is needed at specific pressures to maintain product quality and process stability.



Generally used in

• Water and wastewater treatment plants
• Boiler and cooling water chemical dosing
• Process industries and utility systems
• Chemical, pharmaceutical, and food processing industries