Pulp and Paper Industry

Sample Engagements:

Pressure Vessel and Tank Inspection, Evaluation and Integrity Management:

Issue

A large, integrated, US pulp and paper mill was way behind schedule on integrity inspections of their approximately 450 unfired pressure vessels and tanks (not including paper machine dryers). Vessel deterioration, leaks, etc., were creating unexpected maintenance expenditures and, in some cases, lost production.

 

The mill's default inspection guideline for the majority of these vessels was API 653, which is focused primarily on general corrosion of large, vertical, cylindrical, flat-bottom, carbon steel tanks in petroleum storage service. For example, all insulated tanks/vessels (including stainless steel construction) were inspected using UT at cores in the insulation, and the re-inspection frequency was based on general corrosion rates calculated from these UT data. The problem is general corrosion is not a predominant damage mechanism (DM) for most tanks/vessels in a pulp and paper mill.

The outfall of all this was that the mill was being surprised by vessel deterioration, was wasting considerable time and money performing inspections that provided little useful information about the true condition of the tank/vessel, and was likely missing DMs that were critical to the integrity of the tank/vessel.

Problem Solving

CPI introduced the mill to the concept of Strategic Inspection Design: using knowledge of the DMs most likely to be found in a particular tank/vessel to dictate inspection practice. CPI started by developing a framework for the inspection program, which established the basis for deciding where, how, and how often to inspect each piece of equipment. The next step was to assemble general inspection guidelines and best practices (BPs)-from across the industry and CPI's own suite of BP documents-which apply to the tanks/vessels in this mill. Then, an inspection plan was prepared for each piece of equipment, which listed the probable DMs and how and where to look for them, using the general guidelines and BPs for reference. Visual inspection was the default method used—to verify the presence of DMs and to establish what other, specialized NDE methods were required.

New inspections gave a truer indication of equipment condition and helped with prioritization of future inspections. Inspection scopes, methods and frequencies in the individual inspection plans were also adjusted based upon results of these inspections.

Customer Benefits

The customer saved considerable time and money by eliminating inspections that provided little or no useful data regarding equipment condition.

Mill staff had "peace of mind" that they weren't missing critical DMs in their inspections, and that they knew the true condition of the equipment. Vessel leaks and other deterioration "surprises" that cost maintenance and production dollars were reduced.

Prioritization and scheduling of future inspections was made much simpler.

Industries

Service Areas

  • Corrosion and Materials Engineering
    • Corrosion Control/Protection Design
    • Corrosion Analysis and Material Selection Consulting
    • Failure Analysis - Mode and Root Cause Analysis
    • Cathodic Protection System Design and Evaluation
  • Structural and Mechanical Rehabilitation Services
    • Structural Design Engineering
    • Mechanical Design Engineering
    • Condition Assessment Evaluations
    • Structural Evaluation and Analysis
    • Shop and Field QC Inspection and Support
  • Mechanical Integrity and Inspection Design Services
    • Pressure Vessel and Tank Program Development and Implementation
    • Systematic Inspection Design (SID)
    • Risk-Based Inspection
    • Integrity Evaluation and Analysis
    • Fitness-for-Service Evaluations
    • Welding Consulting and Inspection
  • Coatings and Linings Engineering
    • Consulting
    • Failure Analysis
    • Project Management
    • Quality Control and Inspections
  • Project and Quality Management Services
    • Cost Estimating Services for all Construction Disciplines
    • Project Management Services, Including Planning, Scheduling, and Project Controls
    • Quality Control Inspection and Testing Services
    • Quality Assurance Program Development for New and Rehabilitation Construction
    • Quality Assurance Program Auditing and Oversight Services
  • Training Services
    • Alloy Selection for Corrosive Environments
    • Solving Corrosion and Materials Problems for Plant Engineers
    • Welding Essentials for Plant Engineers
    • Brick and Tile-Lined Equipment Inspection and Repair
    • FRP Essentials for Pulp and Paper Mills
    • Concrete Restoration and Protection
    • Quality Assurance for Capital Projects

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