Latest Trends in Modularisation in Refinery & Petrochemical Plants
Abhijit Dani
Vice President & Business Unit Head,
Critical Process Equipment and Modularisation
Praj Industries Ltd

The modularization concept in Downstream Sector of Hydrocarbon industry is comparatively a newer trend. It is about configuring a plant through the assembly of multiple modules to make a complete plant - An effective alternative to traditional stick-built construction.

This article provides a valuable insight on this new trend. Not only that, it also emphasizes the best practices being followed by one of the leading engineering & Manufacturing company - Praj Industries Limited.

The paradigm of project execution has been rapidly changing due to the change in market and economic scenario in the Downstream Sector of Hydrocarbon Industry. Today, the expectation is to complete the project in shortest possible time to improve the payback period as well as Return on Investment. In addition to that, the safety norms and labour regulations at site are getting tougher and tougher.

In view of achieving the above, the industry has been trying to innovate the way the projects are being conceptualized and implemented.

One of the new trends in project conceptualization in the industry is "Modularisation".

Modularisation is not a new concept in Upstream Oil & Gas Industry particularly in offshore applications as well as remote Oil & Gas processing plants in upstream and midstream sector.

However, in Refineries and Petro-Chemical industry, the concept of modularization is comparatively new because most of the plants are in the areas where labour availability, transportation etc have been favourable compared to remote locations.

What is Modularisation?
Simply putting, modular plant can be defined as "Process System contained within a frame" that allows the complete system to be transported".

Large modules for Oil & Gas Offshore applications - Type 3

Thus, a Module is an alternative to traditional stick-built construction where process system is shipped from the fabrication yard and installed at the site.

Interestingly, there is always a confusion about what exactly it means because module is a very generic term. Often, a module is imagined as a very large system which generally transported on a barge or ship. And as such, the modularisation concept is often considered not practical because many times the plants are located where such huge size equipment can not be transported on road.

Modularisation: Praj Perspective
At Praj, we have a very different perspective of modularisation and we define Modularisation as:

Configuring a plant in a way where multiple Modules are assembled to make a complete plant.

Thus, A modular Plant is:
a. Process System within a structure
b. Complete in all respect till structure limits / battery limits
c. Can be small or large depending on the transportation feasibility
d. Can be single or multiple levels
e. Transportable and easy to assemble at site

To simplify the understanding of the modular plant, we have internally defined modular plants in 3 different Types - These definitions are very helpful while imagining and explaining the configuration of a plant.

Praj way of Modularisation
Being the Technology and EPC company along with our own manufacturing facilities, we - at Praj - are able to conceptualise and design the modular plant in a more construction friendly and cost-effective way. Praj specialises in converting Stick-Built process packages into Type-2 Modular Configuration for Refineries and PetroChemical Plants.

Praj is uniquely positioned to leverage in-house competencies:
a) Process understanding - Being a Technology/Chemical Engg company
b) Multi-disciplinary Engineering
c) Manufacturing/Assembly shops
d) Experience of logistics all over the world
e) Experience of installation of plants - Both - Stick-built and Modular

Over the years, Praj has modularized many packages in various configurations:

1. Fully modularised - Container size - All sub-modules are container size and can be transported in standard containers

2. Fully modularised - Truckable size - Sub-modules are of truckable size (approx. width 4.5 to 5 m)

3. Mixed Modularised - Containerised + Truckable - Some of the submodules are truckable size (4.5 to 5 m width ) and some are container size

4. Partially modularised - Large Equipment Off-Module - Sub -modules are container or truckable size but large equipment like Columns or Reactors are kept stand-alone.

An example of Conceptualising a PetroChemical Plant in a modular configuration.
Size does not matter - BUT sizing matters
Irrespective of the size of the plant, the modularization is possible provided the sizing of individual sub-modules are done thoughtfully. While conceptualizing the sizing, following aspects are considered:
Location of site
a. Safety norms
b. Transportation Limits - From Shop/To site
c. Availability of Cranes

Process of Modularisation - A Joint Development
While developing the modularization concept, the most important activity is joint efforts between the client and modularization company.

At Praj, we always work together with client’s team and follow a stage-wise process:
1. Understanding workshop - Detail understanding of Process Scheme, PFD, P & ID and other details
2. Concept sketches - Configuration
3. Equipment placement
4. Process Validation workshop - Client process team participates to validate the process including Safety norms validation
5. Preliminary Model with major lines
6. Optimisation workshop - Review sizing of modules/Possibility of resizing of equipment
7. Finalisation of configuration
8. Complete Modeling of Modular Plant

Steps 1, 4 and 6 are carried-out in a development workshop method where clients participate to validate the design. This creates a synergy in thought process and approach to the project execution.

Benefits of Modularisation

Challenges in Modularisation
While modularization is a very effective way of configuring a plant, there are certain challenges which must be kept in mind and shall be mitigated.

1. Concurrent Engineering at Client and Module supplier is a MUST.
2. Difficult to accommodate Process Design change after finalsation of configuration
3. Model Review workshops must be ver y intense and elaborate.
4. Weight and cost of structure may be higher ( But many times it saves site civil construction cost )
5. Requirement of suitable space for assembly at shop / yard
6. Meticulous planning required for B/O items as there is less flexibility to accommodate at a later stage.

All these challenges can be overcome by proper planning and teamwork between modularization company and client.

The most impor tant benefit is - Modularisation becomes a “No Surprise” project at site as complete assembly is carried- out in the fabrication shop before the FAT/Pre-commissioning phase.

Over the years of experience in modularization, Praj has developed a competency in conceptualising and manufacturing the modular plants for Refineries and PetroChemical Industry and can claim that:

Modularisation: A safer, faster and cost-efficient way of executing the project