Systematic Approach for Testing & Commissioning of Newly Constructed Alumina Refinery

Hi Friends,

We are well aware that Alumina refinery is a continuous hydro-metallurgical process involving complicated unit operations and unit processes. Testing & commissioning is the 5^th stage in execution of new Alumina refinery which comes after Basic engineering, Detail engineering, Procurement and Erection ensuring mechanical completion. Safe and smooth startup of Alumina refinery with due care of human safety, equipment, process input materials and environment are the basic objectives of successful testing and commissioning of Alumina refinery. Thus, successful commissioning of Alumina refinery has five basic objectives as listed below-

·        No loss time accident,

·        No equipment damage,

·        No risk to environment,

·        No wastage of input materials and

·        Stabilization of plant within shortest period.

Sequence of testing and commissioning of Alumina refinery include following major steps-

Field Checking and Punch Listing: 

Field checking of construction completion status of all equipment, instruments, electrical and associated facilities of Alumina refinery, Co-generation plant, Water supply system, Power distribution system, Compressed air system, cooling tower and Distributed control system is carried out before testing and commissioning of technological plant and equipment. Based on field checking, a list of required additions / deletions / modifications and design changes are recorded with specific identification number for rectification on planned manner as per priority decided by a team of senior technical professionals of the plant.

System Configuration Checking:

You must have gone through the paper on Execution of Alumina refinery on EPC Methodology. Soon after completion of erection activities and before commencement of testing and commissioning trials, system configuration checking is considered to be one of the important steps. This step is the visual inspection of technological and services equipment as per PFDs, P&IDs, ISOs, specifications and design drawings to ensure their readiness for cold water trials. System configuration checking includes the verification of following-

·        Proper installation of equipment,

·        Fixing of valves and pipelines,

·        Alignment and lubrication of rotating equipment,

·        Direction of rotation of motors,

·        Sealing arrangement of pumps,

·        Proper connections of electrical power supply system.

Checking of Instrumentation and Control System: 

This activity is carried out to ensure the readiness of Instrumentation and control system with respect to following critical aspects-

·        Installation of all instruments and controls as per P&IDs,

·        Setting of alarms and tripping system,

·        Process and Safety interlock system,

·        Microprocessor signals,

·        Functioning of local and remote sensing equipment,

·        Correct relay of data / information from field instruments to local as well as Central control rooms,

Checking Cleanliness of Process Vessels and Pipelines: 

This task is carried out by flushing out the process vessels and pipelines to ensure removal of obstruction and blockages in the process circuit just before cold water test run.

Checking of Auxiliary System: 

Performance of auxiliary system like Air conditioners, exhaust fans and connected ducts are checked to ensure desired working environment for instruments, controls, equipment and operating personnel.

Training of Plant Operating Supervisors and Operators: 

Objective of training of supervisory staffs and plant operators is to guide them to commission the Alumina refinery safely. It involves following steps-

·        Formation of team comprising of Managers of various disciplines / departments headed by an Expert.

·        Train the Supervisors aiming to ‘Train the Trainer’ who will train the operators,

·        Review the startup and commissioning procedures,

·        Educating the team with operating and process control parameters including benefits and consequences,

·        Provide technical leadership to facilitate safe, reliable and steady operation of Alumina refinery.

Process and Operating Manual for Systematic Start up: 

This document includes the estimated requirement of input materials and stepwise process sequence for meeting the following basic requirements-

·        Planning for required quantity of input materials,

·        Readiness of Area wise log sheets

·        Fixing the responsibilities of individuals in commissioning team,

·        Normal plant start up procedure,

·        Normal shut down procedure,

·        Emergency plant shut down procedure,

·        Plant Inventory procedure,

·        Procedure for increasing the plant volume steadily,

·        Method for increasing temperature profile of process stream,

·        Guidelines for ensuring adequate supply of condensate to cogeneration plant,

·        Sequence for raising concentration profile of process streams,

·        Planning for aluminate liquor generation and seed charge to initiate generation of seed,

·        Recycling of seed to regular precipitation circuit,

·        Production of hydrate and product alumina.

·        Stabilization of operation of Alumina refinery.

Start up and commissioning of Alumina Refinery:

Bauxite charge to process is considered as the zero date for startup and commissioning of Alumina refinery which is done after caustic concentration build up in selected process vessels to start with for generation of spent liquor and aluminate liquor subsequently. Seed charge enhances the precipitation efficiency thereby generation of seed and product hydrate. Steady control on process and operating parameters stabilizes the plant resulting in target production rate. Calciner is generally commissioned after creating adequate stock of hydrate in the storage shed.

Performance Tests for Plant and Equipment: 
Test runs are conducted with standard agreed procedure for individual plant, equipment and facilities in order to assess the guaranteed performance. However, performance tests for entire Alumina refinery are carried out after stabilization of plant operation to check the assigned production rate and efficiency parameters as agreed by technology supplier, equipment supplier and engineering consultant. 

The above stated guidelines are generally followed for systematic testing, start up and commissioning including establishing performance guarantee parameters of newly constructed Alumina refinery.

Hope, you will like to have a look at the article on "Engineering and execution stages of Alumina refinery."

Best regards.

Rajendra Kunwar

E.Mail: rajendra@ceti.co.in

Website: www.ceti.co.in

PROMISING ALUMINA REFINERY PROJECTS IN INDONESIA

Hi Friends,

As discussed in previous articles, about 89% of alumina produced in the World is used for manufacture of aluminium metal and remaining 11% for production of chemicals and other non-metallurgical applications. Thus calcined alumina as well as hydrated alumina (Hydrate) is broadly characterized in two categories-

•       Metallurgical grade alumina or Smelter grade alumina (MGA or SGA)) and
•       Non-metallurgical grade alumina or Chemical grade alumina (NMGA or CGA).

Though the volume of CGA market is less compared to that of SGA but the profit margin in CGA is much higher as its selling price ranges from 2 to 5 times of that of SGA. Presently, the market potential of CGA across the globe is estimated at around 5.8 to 6.0 million tonnes per annum. Out of total CGA demand in International market, specialty grade hydrates have market share of over 50% i.e. about 3.0 to 3.2 Mtpa being used as feed stock for manufacture of Aluminium sulphate, Fire retardant fillers, Tooth paste, Sealing rings for rotating equipment, Thread guides, Polish, Paints, Ceramics, Abrasive, High temperature refractory and American diamond. During last couple of years, selling price of CGA has shown increasing trend along with increase in its demand whereas selling price of SGA has shown downward trend hovering at the level of US$ 350-360 per tonne of calcined alumina because of lower LME price of aluminium metal. Now, let me give the brief account of bauxite reserves and alumina scenario with more focus on salient features of Alumina projects in Indonesia in subsequent paragraphs.

As per data available on public domain, bauxite is available in Tayan, Munggu Pasir, Mempawah and West Kalimantan region in Indonesia. West Kalimantan is having total bauxite reserves of over 2000 million tonnes with proven reserves of over 800 million tonnes of bauxite. The bauxite is predominantly gibbsitic in nature with average quality of about 43% total alumina, about 38.6% available alumina and around 3% reactive silica. The bauxite in Indonesia has been seen in low lying hills with overburden varying from 0.60 m to 3.8 m and nodular bauxite horizon from 2.2 to 5.2 m. The geographical studies indicate that these bauxite deposits were formed by in-situ weathering. Till last year, the country was exporting bauxite to china and other countries but in the recent past, the Indonesian government has totally banned the export of bauxite and putting more focus on processing of bauxite for production of value added products.

In Indonesia, there are two major Alumina projects in West Kalimantan namely Tayan Alumina Project and Mempawah Alumina Project under execution and active consideration as outlined here under.

Tayan CGA Project: Tayan bauxite mine commenced its operation in early 2010 and was exporting bauxite to China and Japan. Construction of Tayan Alumina Project was started in April 2011 aiming to mechanical completion schedule in December 2013 and trial production in January 2014. The capacity of this plant is 0.300 million tonnes for production of wide varieties of Chemical grade hydrates and aluminas. The estimated investment in this project was US$ 500 million with the technology supplied by Showa denko (SDK), Japan. The actual mechanical completion of this project was done in December 2014 and commercial production commenced in February 2015.

Mempawah SGA Project: The capacity of this plant is 1.2 million tonnes of SGA to be supplied as feed stock to Aluminium Smelter. The estimated capital investment will be about US$ 1.5 billion. The construction of this plant will be started by early 2015 with mechanical completion target of December 2017.

Both Alumina projects have promising future because of locational advantages, availability of good bauxite reserves, adequate coal reserves and adoption of advanced technology. I wish grand success of both projects.

We seek your valued comments / opinions / additional information, if any.

Regards.

Rajendra Kunwar
rajendra@ceti.co.in
www.ceti.co.in