Pressure Control Philosophy of Ammonia Storage Tank PIC91124

Pressure Control Philosophy of Ammonia Storage Tank PIC-91124 S. Hasnain H. Zaidi Management Associate (Urea Operations)

Table of contents 1. FFBL Ammonia Storage facility- An Overview 2. Ammonia Storage Tank- An Introduction 3. Causes of pressure deviation 4. Pressure Control Loop- Schematic diagram and Description

FFBL Ammonia Storage Facility • Introduction • Mechanism

Working mechanism of storage area 1 st Stage Compressor 2 nd Stage Compressor Condenser Flash Vessel Ammonia Storage Tank Incoming Ammonia from NH 3 Plant Urea/ Dap

Ammonia Storage Tank (AT-911) • Introduction • Assembly

50 mm Fiber glass Resilient blanket Outer tank 150 mm Perlite on suspended deck Inner Tank Double wall Ammonia Storage Tank AT-911 Loose Perlite 77 mm Sand Wooden Blocks Asphalt 102 mm Foam Glass

Pressure Control Philosophy Why pressure of AT-911 carries such a high consideration? ? • Phase consideration • Rapture • Collapsing

Causes of Pressure deviation There are two ways to deviate the tank pressure 1. At positive Pressure 2. At negative pressure

Storage Tank-Pressure Control Settings 0. 100 Kg/cm 2 g PSV open 0. 0940 Kg/cm 2 g Flare valve open 0. 0915 Kg/cm 2 g Close flash drum outlet to tank 0. 0850 Kg/cm 2 g High pressure alarm 0. 0700 Kg/cm 2 g Start emergency compressor 0. 0633 Kg/cm 2 g Start LAG compressor 0. 004 Kg/cm 2 g Normal Tank Operating Pressure 0. 0180 Kg/cm 2 g Stop emergency compressor 0. 0150 Kg/cm 2 g Open recycle Valve 0. 0130 Kg/cm 2 g Low pressure Alarm 0. 0110 Kg/cm 2 g Open warm ammonia to tank 0. 0035 Kg/cm 2 g Open Nitrogen make up valve -0. 005 Kg/cm 2 g Vacuum relief valve open

Normal Operating Pressure 0. 04 Kg/cm 2 g Emergency Compressor 2 g At Pressure ---- 0. 0700 Kg/cm 0. 0180 22 g 2 At At Pressure -------0. 0225 0. 0150 Kg/cm g 2 Start At Pressure -------0. 100 Stop Emergency Compressor 2 g At Pressure -------0. 0940 Kg/cm At Pressure -------0. 0633 Kg/cm g 2 2 At At Pressure -------0. 0035 -0. 005 Kg/cm gg Stop Open LAG Recycle Compressor Valve PSV Open Vent Valve 2 g Start LAG Compressor At Pressure -------0. 0850 Kg/cm Open Vacuum Nitrogen Relief Make Valveup Open Line 2 g At Pressure -------0. 0130 0. 0110 Kg/cm 2 g At Pressure -------0. 0915 Kg/cm High Pressure Alarm Open Low Warm Pressure Ammonia Alarm. Valve Stop Incoming Ammonia to Tank Flare PSV Caseofof In. Case Decreasing Increasing Pressure 1 st Stage (LEAD) Compressor 1 st Stage (LAG) Compressor Stair Case Tower Nitrogen 2 nd Stage Compressor Flash Vessel Warm NH 3 Ammonia Storage Tank Incoming Ammonia from NH 3 Plant Urea/ Dap Condenser

questions are welcomed!! !