Corrosion Aspects and Materials of Construction in Ammonium Nitrate and UAN Plants: 5-Day Specialized Training Course

Course Overview

This intensive 5-day ammonium nitrate and UAN corrosion training provides specialized knowledge of corrosion mechanisms, materials selection, and integrity management for ammonium nitrate (AN) and urea-ammonium nitrate (UAN) solution manufacturing facilities. Designed for materials engineers, corrosion specialists, plant engineers, and safety professionals in fertilizer production.

Target Audience: Materials engineers, corrosion specialists, integrity engineers, plant engineers, maintenance managers, safety professionals, and technical personnel in AN and UAN production facilities.

Course Objectives:

• Understand corrosion mechanisms in AN and UAN environments

• Master materials selection for different process conditions

• Identify failure modes and prevention strategies

• Implement inspection and monitoring programs

• Ensure process safety and regulatory compliance

Day 1: AN and UAN Processes and Corrosion Fundamentals

Morning Session: Process Overview

Understanding Production Processes

Foundation of AN and UAN manufacturing:

Ammonium Nitrate Production:

• Ammonia and nitric acid neutralization reaction

• NH₃ + HNO₃ → NH₄NO₃ + heat (exothermic)

• Neutralizer reactor: 170-185°C, slightly acidic pH

• Evaporation and concentration: 95-99.5% AN solution

• Prilling or granulation processes

• Product forms: prills, granules, solutions

• Plant capacities: 1,000-3,000 MTPD

UAN Solution Production:

• Urea and ammonium nitrate mixture in water

• Common grades: UAN-28, UAN-30, UAN-32 (% nitrogen)

• Typical composition: 35-45% AN, 35-45% urea, water

• Production temperature: 60-80°C

• Salt-out temperature considerations

• Storage and handling requirements

Corrosive Environment Characteristics:

• Ammonium nitrate: oxidizing, acidic to neutral

• Nitric acid carryover effects

• Ammonia excess buffering

• Temperature impacts on corrosivity

• Chloride contamination sensitivity

• Dissolved oxygen influence

Afternoon Session: Corrosion Mechanisms

How Corrosion Occurs

Understanding corrosion fundamentals:

General Corrosion:

• Uniform attack on carbon steel

• Passivity breakdown in stainless steels

• pH effects: acidic solutions most aggressive

• Temperature acceleration of corrosion

• Concentration effects on corrosion rates

• Oxygen availability impact

Stress Corrosion Cracking (SCC):

• Chloride SCC in stainless steels: critical concern

• Nitrate SCC in carbon steel (rare but possible)

• Required conditions: stress, environment, susceptible material

• Temperature thresholds (>60°C increases risk)

• Catastrophic failure potential

• Historical incidents and consequences

Localized Corrosion:

• Pitting corrosion: chloride and nitrate synergy

• Crevice corrosion in flanges and gaskets

• Under-deposit corrosion

• Galvanic corrosion at dissimilar metal junctions

• Preferential weld attack

Intergranular Corrosion:

• Sensitization of stainless steels

• Grain boundary attack in HAZ

• Carbide precipitation effects

• Stabilized grade performance

• Prevention strategies

Erosion-Corrosion:

• High-velocity solution attack

• Two-phase flow damage

• Pump and valve failures

• Cavitation in pumps

• Velocity limitations by material

Day 2: Materials Selection for AN Plants

Morning Session: Neutralization and Evaporation Section

Materials for High-Temperature AN

Mastering material selection:

Neutralizer Materials:

• Stainless steel 304L/316L: baseline materials

• Alloy 20 (Carpenter 20Cb-3): excellent performance

• Alloy 31 (UNS N08031): high corrosion resistance

• Duplex stainless steels: 2205 for severe service

• Titanium: exceptional resistance, high cost

• Temperature and pH considerations

Evaporator Materials:

• 316L stainless steel: moderate conditions

• Super austenitic grades: 904L, AL-6XN

• Alloy 20: preferred for acidic conditions

• Titanium tubes: superior performance

• Shell materials: carbon steel or 304L

• Chloride content critical (<50 ppm)

Selection Criteria:

• Solution pH (acidic to neutral range)

• Operating temperature: 150-200°C

• Chloride contamination levels

• Nitric acid concentration

• Ammonia excess buffering

• Equipment criticality and cost

Afternoon Session: Finishing and Storage

Materials for Downstream Operations

Understanding lower temperature materials:

Concentration and Finishing:

• Prilling tower: carbon steel with coatings

• Granulation drum: stainless steel 304L/316L

• Product conveyors: carbon steel or stainless

• Dust collection: 304L or FRP

• Screening equipment: carbon steel adequate

• Coating and anti-caking systems

Storage Systems:

• AN solution storage: 316L or Alloy 20

• Temperature control critical: prevent crystallization

• Heating coils: titanium or Alloy 20

• Tank design: ASME codes compliance

• Insulation and heat tracing

• Vent and pressure relief systems

Alternative Materials:

• Glass-lined equipment for acidic service

• Fluoropolymer linings: PTFE, PFA

• Rubber linings: butyl, natural rubber

• Fiber-reinforced plastics (FRP)

• Protective coatings for carbon steel

• Epoxy and polyurethane systems

Day 3: Materials Selection for UAN Plants

Morning Session: UAN Production Materials

Materials for UAN Solutions

Mastering UAN-specific selection:

Reactor and Mixing Section:

• Stainless steel 316L: most common

• Alloy 20: excellent corrosion resistance

• Duplex 2205: improved resistance

• Carbon steel: limited to low-temperature, low-chloride

• Agitator materials: 316L or duplex

• Heating systems: stainless steel coils

Temperature-Dependent Selection:

• <60°C: 316L adequate with chloride control

• 60-80°C: 316L or duplex recommended

80°C: super austenitic or Alloy 20

• Chloride limits stricter at higher temperatures

• Salt-out temperature considerations

• Seasonal variation impacts

UAN Solution Characteristics:

• Mildly corrosive compared to pure AN

• Urea buffering effect

• pH typically 7-8 (near neutral)

• Chloride sensitivity remains critical

• Temperature cycling effects

• Contamination from raw materials

Afternoon Session: Storage and Handling

UAN Distribution Systems

Understanding storage and transfer materials:

Storage Tanks:

• Carbon steel: adequate for low-chloride UAN

• Stainless steel 304L/316L: preferred

• Polyethylene and FRP: non-metallic options

• Tank capacity: 1,000-50,000 tonnes

• Temperature maintenance systems

• Agitation to prevent settling

Transfer and Loading:

• Piping: carbon steel or 304L stainless

• Pumps: 316L stainless steel standard

• Loading arms: stainless steel

• Hoses: reinforced rubber or composite

• Valves: stainless steel or bronze

• Gasket materials: PTFE or graphite

Applicator Equipment:

• Field application equipment: carbon steel

• Spray nozzles: stainless steel or plastic

• Seasonal corrosion: outdoor exposure

• Cleaning and flushing requirements

• Atmospheric corrosion protection

• Maintenance and inspection

Day 4: Corrosion Prevention and Monitoring

Morning Session: Prevention Strategies

Proactive Corrosion Management

Implementing prevention programs:

Process Control:

• pH control: slightly acidic to neutral optimal

• Ammonia excess maintenance

• Chloride monitoring and control (<50 ppm)

• Temperature management within design

• Dissolved oxygen minimization

• Raw material quality specifications

Design Considerations:

• Avoiding crevices and dead-legs

• Proper drainage and low-point drains

• Smooth flow transitions

• Stress concentration minimization

• Material compatibility at joints

• Thermal expansion accommodation

Inhibition Programs:

• Passivating agents for stainless steel

• Ammonia as pH buffer

• Oxygen scavenging chemicals

• Temporary inhibitors during shutdowns

• Nitrogen blanketing in storage

• Water quality control

Operational Best Practices:

• Controlled startup and shutdown

• Temperature ramping procedures

• Avoiding thermal shock

• Regular system flushing

• Equipment idle time management

• Preventive maintenance scheduling

Afternoon Session: Monitoring and Inspection

Detecting Corrosion Early

Implementing monitoring programs:

Corrosion Monitoring:

• Corrosion coupons: weight loss measurement

• Electrical resistance (ER) probes

• Ultrasonic thickness monitoring

• Process analyzers: pH, chloride, conductivity

• Temperature profiling

• Data trending and analysis

Non-Destructive Testing:

• Visual inspection procedures

• Ultrasonic thickness testing (UTT)

• Radiographic testing for welds

• Magnetic particle testing

• Liquid penetrant testing

• Infrared thermography for CUI

Inspection Planning:

• Risk-based inspection (RBI) methodology

• Critical equipment identification

• Damage mechanism assessment

• Inspection intervals optimization

• Seasonal inspection considerations

• Shutdown planning and coordination

Sample Analysis:

• Chloride content analysis

• pH measurement and trending

• Heavy metal contamination

• Nitrate and ammonia concentration

• Corrosion product analysis

• Metallographic examination

Day 5: Safety, Incidents, and Integrity Management

Morning Session: Process Safety and Incidents

Safety in AN and UAN Plants

Understanding safety considerations:

AN Detonation Hazards:

• Thermal decomposition pathways

• Contaminant sensitivity: organics, chlorides, metals

• Historical catastrophic incidents

• Beirut (2020), West, Texas (2013)

• Prevention through contamination control

• Storage and handling regulations

Material-Safety Interaction:

• Corrosion leading to contamination

• Iron oxide catalyzing decomposition

• Chloride impact on stability

• Organic material ingress prevention

• Proper material selection importance

• Cleaning and decontamination procedures

Case Studies:

• Material failure leading to safety incidents

• Chloride-induced SCC failures

• Contamination from corrosion products

• Tank rupture incidents

• Piping failures and releases

• Lessons learned and corrective actions

Emergency Preparedness:

• Leak detection and monitoring

• Emergency response procedures

• Material compatibility in emergencies

• Neutralization and cleanup

• Environmental protection

• Incident investigation protocols

Afternoon Session: Integrity Management

Comprehensive Asset Management

Developing management systems:

Regulatory Compliance:

• OSHA PSM 1910.119: AN facilities

• EPA RMP requirements for AN

• ATF explosives regulations

• UN classification and storage

• Mechanical integrity programs

• Process hazard analysis

Industry Standards:

• EFMA (European Fertilizer Manufacturers): guidelines

• IFA (International Fertilizer Association): best practices

• ASME codes for pressure vessels

• API inspection codes

• NACE corrosion standards

• ISO safety management

Integrity Management Elements:

• Asset inventory and criticality ranking

• Corrosion damage mechanisms identification

• Inspection and testing procedures

• Fitness-for-service assessments

• Remaining life calculations

• Repair versus replacement decisions

Documentation and Records:

• Material traceability

• Inspection history and reports

• Corrosion monitoring data

• Maintenance records

• Incident investigations

• Management of change documentation

Continuous Improvement:

• Performance metrics and KPIs

• Benchmarking against industry

• Technology upgrades evaluation

• Training and competency programs

• Lessons learned integration

• Innovation in materials and methods

Course Deliverables

Participants Receive:

• Comprehensive corrosion and materials manual

• Materials selection decision trees

• Inspection procedure templates

• Process safety checklists

• Case study compilation

• Regulatory compliance guides

• Professional certificate of completion

Interactive Components:

• Materials sample examination

• Failure analysis workshops

• Material selection exercises

• Safety scenario discussions

• Group case study analysis

Why This Training Is Critical

Key Benefits:

• Prevent equipment failures and production losses

• Ensure process safety and prevent incidents

• Optimize material selection and costs

• Extend equipment service life

• Maintain regulatory compliance

• Build organizational expertise

ROI:

• Reduced unplanned shutdowns

• Lower maintenance and replacement costs

• Improved safety performance

• Enhanced regulatory standing

• Avoided catastrophic incidents

Keywords: ammonium nitrate corrosion, UAN materials, fertilizer plant corrosion, stainless steel selection, chloride stress corrosion cracking, AN plant safety, materials of construction, corrosion monitoring, integrity management, process safety management

Word Count: ~1,000 words

This SEO-optimized course outline provides comprehensive coverage of corrosion and materials topics for ammonium nitrate and UAN plants, addressing mechanisms, prevention, safety, and management for reliable and safe operations.