Wednesday 4 July 2012

Risk Based Inspection (RBI) Program-me IN FERTILIZER INDUSTRIES

More organizations now find that their stakeholders demand increased
accountability and transparency on sustainability-related issues.
Meanwhile, corporations’ intricate global operations create more
complicated challenges for any EHSQ compliance team.  An EHSQ compliance
platform must assist, not hinder, organizations who need to locate those
“pain points.”  Such a system must be centralized yet multifunctional;
offer data management and analysis for all layers of an organization; be
easily accessible yet secure, and manage and transform data in various
formats.

   o    How  to  improve  energy  efficiency  initiatives  throughout  your
      organization



   o    Monitor EHSQ compliance, identify opportunities for improvement, and
      achieve advancement in EHSQ performance.



   o    How  an  effective  EHSQ  platform  can address various regional and
      business  cultures--   how  to  address  any  resistance  within your
      organization while gaining increased buy-in 
Modern  Process  Plants,  especially  fertilizer  plants  are  designed for flexible  production  and  maximum  recovery  of  energy.  Provision  of  a Distributed  Control  System  (DCS)  along with an Advanced Process Control (APC)   philosophy   can   serve   this  purpose.  The  objectives  of  APC implementation in a Gas based Ammonia Plant are as follows:

Minimization of specific energy consumption.

Stabilization of plant load even during fluctuations in variables such as

Natural gas pressure, flow or quality.

Precise control of “Steam to Carbon” ratio in the Primary Reformer for

steam economy.

Optimum control of Oxygen in the Flue Gas.

Control of Synthesis gas quality i.e. the Hydrogen to Nitrogen Ratio.

Accurate control of Methane slippage from the Primary and Secondary

Reformers..

                   Risk Based Inspection (RBI) Programme

The main aim of the Risk Based Inspection programme is to;

- Maximize safety by evaluating risks for individual equipments/accessories

and recommend methods to reduce risks.

- Optimize productivity by optimizing plant shut down timings

- Optimize inspections, testing and maintenance to improve plant

reliability.

- Improve the understanding of the condition of plant hardware and its

management for long term plant operation.

- Make optimal use of resources through a risk based approach.

Equipment that should be covered in the RBI programme are;

- Furnaces

- Reaction vessels

- Heat exchangers

- Boilers

- Storage tanks/Vessels

- Piping and Pressure Relief valves

Preparation of comprehensive lists of pressure equipment based on criticality in terms of services and set up inspection programme accordingly

- Prioritize the pressure equipment so that the assessments to be carried out enable the major outcomes from the critical plant to be reported as early as possible.

- Develop process loops for piping such that each process loop has the same environment and similar risk exposure.

- Complete a risk-based assessment so that meaningful profiles of failure risk, failure likelihood and failure consequence can be established for each “nominated”

pressure item or process loop in the ammonia plant.

- Prepare inspection programmes for pressure equipment and piping to ensure these items of plant are effectively operated, maintained and their condition assessed.

- Recommend actions, which will be needed to be carried out to ensure safe

& reliable operation of the plant prior to and after planned shutdown.

- Use of proprietary Reliability Management System (RMS) software of the

Vendor who will be entrusted to carryout the study.

- Recommend preliminary scope of work and period of the planned upcoming

shutdown.

   A Risk based Inspection study helps to standardize the inspection

   procedures to optimize production and time span for planned shutdown.

   b. Improving Plant Reliability through Corrosion Monitoring

   Corrosion   attacks   can  reduce  equipment  performance  and  lead  to

   unexpected  failures  and  plant shut downs. Corrosion attack of process

   equipments  may  be  external or internal. External attack is by ambient

   environment  whereas  internal attack is caused by process fluid handled

   inside.  Corrosion  monitoring  is  an  essential input in Residual Life

   Assessment and Aging Management Programme.

   Corrosion monitoring techniques are;

   - Methods that indirectly measure parameters related to corrosion and

   inter corrosion

   behavior from some model of corrosion process, e.g. electrochemical

   potential, pH and temperature.

   - Methods that directly measure corrosion behavior, e.g.,

   Non-destructive Inspection,

   Material Test Coupons, Galvanic Currents etc.

   -- Corrosion Monitoring Techniques:

   Direct Measurements

   • Non Destructive Inspection (NDI)

   • Electrical Resistance (ER) Probes

   • Material Test Coupons

   • Galvanic Currents

   • Cyclic Potentiodynamic Polarization (CPP)

   • Linear Polarization Resistance

   • Electro Chemical Noise (EN)

   • Electrochemical Impedance Spectroscopy (EIS)

   Indirect Measurements

   • Potential

   • Biological Count

   • Hydrogen

   • pH

   • Temperature

   • Conductivity

   • Specific Ions

   Periodic assessment is the most common method of corrosion monitoring

   and can help to:

   • Evaluate materials performance under specific service conditions

   • Aid in proper material selection

   • Evaluate and control the production process

   • Provide necessary data for Residential Life Assessment

   c. Improving Plant Reliability by Conducting Regular Safety Audits

   BY Dr. Amar Nath Giri

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