MONEL 400 EXPANSION JOINT

For a chemical plant in the United Kingdom producing chlorine, caustic soda and chlorinated derivatives, Belman has successfully designed and manufactured a replacement Expansion Joint in Monel 400. The original Expansion Joint design has been in operation for 20+ years and has demonstrated reliable performance under demanding process conditions; therefore, as per client request, Belman developed a dimensionally equivalent replacement design, ensuring seamless integration in the piping system. The new Expansion Joint was engineered based on the drawings and specifications provided by the client, while being upgraded to comply with the latest EJMA standard.

 

CLIENT ISSUE

The chemical plant needed to replace an Expansion Joint that had reached the end of its service life. The client was extremely satisfied with the design and material composition of the Expansion Joint and thus wanted a similar solution to take its place. For this reason, the client was looking for a highly experienced Expansion Joint manufacturer with proven expertise in special alloys and unique solutions, and – although the original Expansion Joint was produced by another manufacturer – chose Belman for the job.

 

BELMAN SOLUTION

Monel 400 Expansion Joint

By combining proven design principles with updated engineering practices, Belman delivered a solution tailored to the demanding conditions of the chemical process environment. The original Expansion Joint design had been in operation for 20+ years with proven performance; therefore, as per client request, Belman developed a dimensional equivalent design based on the drawings and specifications provided by the client, ensuring straightforward integration into the piping system. The design was, however, upgraded to meet the latest EJMA standard and incorporated additional client-requested features, such as protective covers and lifting lugs. The Expansion Joint solution is a DN 900 Tied Expansion Joint with twin Bellows and a middle pipe. Due to the process flow velocity combined with possible presence of particles in the media, it has been manufactured with inner sleeves to protect the Bellows and ensure reliable long-term operation.

Echoing the configuration of the existing Expansion Joint design, the new Expansion Joint is equipped with two tie rods. Maintaining this configuration allowed the client to avoid eventual space issues. The nuts on the tie rods are strategically positioned to control the movement absorption, allowing +/-10 mm axial movement as well as +/- 30 mm lateral movement generated by the operation.

All parts of the Expansion Joint in contact with the process media are made from Monel 400 (2.4360), i.e. the Bellows, inner sleeves, middle pipe and pipe ends. All parts not in media contact are made from other materials, such as protective covers in 1.4307 (AISI 304L) and flanges in carbon steel and coated with primer. The protective cover was added at the client’s request to provide mechanical protection of the Bellows; furthermore, it provides the option of insulation, thereby reducing the skin temperature.

As with the existing design, transport bars were included to protect the Expansion Joint during transport, handling and installation. In addition, lifting lugs mounted on the flanges were incorporated as a client requirement, ensuring safe lifting without damaging the Expansion Joint during transportation, handling and installation.

 

Why choose Monel 400 for the Expansion Joint?

The process media at the installation point of the Expansion Joint in the chemical plant is brine. Brine is a concentrated solution of sodium chloride (NaCl) dissolved in water. This environment is highly corrosive, as the solution contains a high concentration of chloride ions and may also contain dissolved oxygen and traces of chlorine. Such conditions can cause rapid corrosion of many common steels. For this reason, Monel 400 is often selected for components used in brine-carrying piping systems, including Expansion Joints. Monel 400 is a nickel-copper alloy widely used in chemical plants, Oil & Gas and marine applications due to its excellent corrosion resistance in chloride-containing environments, acids, seawater and brine solutions. In addition to outstanding corrosion resistance, Monel 400 offers high mechanical strength, good ductility and excellent resistance to stress corrosion cracking, which is a common challenge for many stainless steels. By selecting Monel 400, the client benefits from a long service life, reliable operation and good corrosion resistance in the aggressive brine environment.

 

Belman – highly experienced in Expansion Joints made from special alloys

Since 1994, Belman has developed extensive expertise in designing and manufacturing Expansion Joint solutions made from special alloys for demanding environments. Through decades of experience and a wide range of international projects, Belman has gained deep knowledge in selecting and working with advanced high-alloy materials such as Duplex, titanium, Hastelloy, Incoloy, Inconel, Super Duplex, Monel and other high-performance alloys. These materials are often required in industries where piping systems operate under extreme conditions, such as high temperatures, aggressive media, high pressure and corrosive environments. Belman’s engineers work closely with clients to identify the most suitable material and cost-efficient solution for each specific application. Belman has successfully delivered numerous such solutions for industries including in the Oil & Gas sector, energy sector, shipping industry, chemical plants and steel plants etc. Some examples include high-temperature Expansion Bellows made from Alloy 188, Hastelloy C-22 Bellows made for a high-pressure heat exchanger, and Super Duplex Bellows made for a steam turbine.