Manufacturer of heavy equipment for the Oil & Gas industry

For over half a century, the Oil and Gas division of ATB Group has been offering know-how and production capacity to the world's leading petrochemical companies.

Oil and natural gas touch our lives in countless ways every day. More than 60 percent of our daily energy needs is supplied by hydrocarbons and gas, keeping us warm in cold weather and cool in hot weather, cooking our food and heating our water, generating our electricity, and powering our cars, buses, trains, ships and planes.

ATB Group is an international designer and manufacturer of process equipment for the Oil and Gas industry, a specialist in ammonia and urea production plants, petrochemical plants and gas treatment plants.
Innovation, diversification and research of new markets are our guidelines.We create new collaborative business models, by establishing relationships with partners, suppliers and customers, and leveraging our worldwide sales network.

AIPER MEMBER Associate member of AIPE (Italian Association of Pressure Equipment)

Process Equipment

ATB Group is an international designer and manufacturer of process equipment for the petrochemical industry, ammonia and urea production, gas treatment plants.

Heavy equipment business unit takes advantage of ATB Group long and successful operation experience as a world leader in the design, fabrication and inspection of equipment utilized in the oil and gas industry, refinery and petrochemical plants operating under the most severe pressure and temperature conditions under corrosion and hydrogen attacks.

ATB Group's design experience covers almost the complete range of oil and gas components required for Upstream, Midstream and Downstream applications. Due to the continuous improvement required for higher productivity of refineries and petrochemical plants, the thickness, diameter and weight of reactors and vessels have increased drastically and reached the limits of the current manufacturing technology.

ATB Group has become one of the world leaders in manufacturing of Cr, Mo Steel alloys including the lastest generation of vanadium modified alloys. The company has developed special expertise in welding stainless steel and duplex urea grade corrosion resistant materials.

Equipment list

Italian design and our fabrication skills and competencies have prepared us to adequately deal with a wide range of equipment for oil&gas applications.

ATB Group focus is on the most challenging jobs.  High-end, reliable facilities and skilled workers have enabled the company to specialize in manufacturing pressure vessels of exceptional characteristics. 


  • Hydroprocessing Reactors and Separators 
  • Ammonia Converters and Urea Reactors
  • Heavy Wall Columns
  • Heavy Wall Process Separators & Drums
  • Large Diameter Columns & Towers
  • Storage bullets
  • Shell & Tube HE 

The company has delivered equipment up to 358 mm thick and a maximum weight of 1620 tons in one single piece. Some of our achievements are as follows:

Thickness:           CLG process HCK reactor 358 mm

Weight:               UOP Process MHC Reactor, 1620 tons

Length:                C2 Splitter Column, 100 m

Temperature:     CCR Reactor that withstand 650°C

                             Columns that withstand –196°C

Pressure:            Pressure vessel that withstand 46 MPa


In the early 1970’s, ATB became the first company in Italy that was qualified by ASME as an authorized holder of U, U2 stamps for manufacturing pressure vessels intended for the United States. 

Due to an ever-increasing productivity of refineries and petrochemical plants, the thickness, diameter and weight of the relevant reactors/vessels have increased, reaching the limits of the current manufacturing technology. The company has been able to improve its fabrication technology to keep pace with this increase as well as with the market requirements for upgrading the manufacturing materials.

All the steels produced under ASTM, DIN, British standards, and all the western European standards are widely used by the company to make pressure vessels. These include: carbon steel, carbon steel with HIC properties, carbon steel for low temperature applications, all low alloy steels (1/2Mo, 1Cr 1/2Mo up to 2 1/4Cr 1Mo including the lastest developments of the materials with enhanced properties and Vanadium modified chemical composition), 9% nickel steels for cryogenic service, and stainless steel. 

ATB Group is now among the very few companies that are qualified to work extensively this Vanadium modified materials.

O&M Services

The Heavy Equipment division of ATB Group can also offer a set of Operation & Maintenance services through its subsidiaries.

Thanks to its expertise and through its operating units, ATB Group offers its customers a complete set of services for Operation & Maintenance:

  • Inspection Activities
  • On-site interventions
  • Maintenance Engineering
  • Supply and Installation of Spare Parts
  • Staff Training


  • On-site Non-Destructive testing
  • Ultrasonic (TOFD and Phased Array) Computerized Testing
    • Visual inspections
  • Chemical and Metallographic Analyses at ATB laboratory
  • Preparation of check routine
  • Evaluation of residual life checking: corrosion, reduction of thickness, weakening and cracks.

During scheduled or unexpected shutdowns, ATB Group can:

  • Repair damaged components in service
  • Prepare of welding procedures and execute on-site activities with specialized staff
  • Schedule and supervise work
  • Heat treatment procedures before and after welding
  • Supply welding consumables 
  • Install process internals elements


  • Stability of the components and risk analysis
  • Residual life assessment for components and systems
  • Analysis of repair methods or possible modification
  • Analysis and implementation of the necessary changes for new design conditions

To support the maintenance activities, we can:

  • Conduct periodic inspections
  • Supply special equipment
  • Qualify NDT operators and validate check routines
  • Destructive testing
  • Maintenance Plans

To support the operation activities, ATB Group offers:

  • Construction and installation of spare parts
  • Study of the changes / improvements that may be required
  • Spare part stock optimization

In order to offer a 360 ° service its customers, the company can provide the following specialized training courses:

  • Non-Destructive Testing (NDT)
  • Welding Procedures
  • Maintenance Procedures for our equipment

Site activities

We are one of the very few companies experienced in site assembling heavy and large pressure vessels.

The ever-increasing size and weight of vessels combined with the remote location of refineries and petrochemical plants has made transport of heavy and large equipment quite difficult.

We are commonly requested to manufacture reactors or vessels in sections in our ATB workshops and to perform the final assembly at the project site.

ATB Group has, therefore, developed capabilities to become one of very the few companies experienced in site assembling heavy and large pressure vessels.

In the 1990’ s, we supervised of the site assembly of several acrylonitrile reactors in China for Tecnimont and of FCC Reactor/Regenerator units at the ExxonMobil refinery in Sriracha, Thailand.

Our experience has been further expanded in recent years. Since 2002, we have completed many projects that required site assembling heavy wall hydro-processing reactors made of low alloy V modified steel.

Our success story includes completion of several major projects that required assembling reactors at the following plants:

  • 2002 PEMEX, Tula Refinery, Mexico: 1 HDS Reactor (weight: 580 tons, wall thickness: 147 mm)
  • 2007 ENI, S.Nazzaro Refinery, Italy: 1 HDT reactor (weight: 510 tons, wall thickness: 192 mm)
  • 2010 ENI, S.Nazzaro Refinery, Italy: 2 Reactors (total weight: 800 tons, wall thickness: 135 mm)
  • 2010 ENI, S.Nazzaro Refinery, Italy: 2 Separators (total weight: 680 tons, wall thickness: 202 mm)
  • 2015 Calumet Refinery, Montana, USA: 1 HDT reactor (weight: 940 tons, wall thickness: 186 mm)


However, this specialized on-site fabrication expertise is only an addition to the usual activities of our ATB workshop. Therefore, the working conditions of each site are carefully evaluated so that a maximum support can be provided by the end users and local engineering companies.


ATB Group Heavy Equipment manufacturing activities are carried out in two workshops.

ATB Group Heavy Equipment manufacturing activities are carried out in two workshops in the Northern part of Italy, the headquarters in Roncadelle, Brescia, and the Porto Marghera assembly plant, with a total area of 155,000 m2, out of which 40,000 m2 are covered.


Each workshop is fully equipped with a comprehensive list of modern equipment for welding, cladding, machining, rolling and forming.

Thanks to our high-end facilities and skilled workers, ATB Group is specialized in the manufacturing of reactors and pressure vessels with the following records:

  • Max thickness: HCK Reactors 358 mm thick
  • Max weight: MHC Reactor weighing 1620 tons
  • Max length: Heavy Column 100 m long
Browse our project portfolio and discover some of the best jobs we have completed.

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ATB Riva Calzoni S.p.A.

ATB Riva Calzoni S.p.A. Logo
  • Address: Via Industriale 13, 25030 - Roncadelle (BS) ITALY
  • Phone: +39 030 25811
  • Fax: +39 030 2581222
  • Email: