Karratha Gas Plant

Outcome

• Economic design, compliant with industry standard and client specific requirements
• Design proved successful in operation and was identically replicated for train V at client’s request

Background

The Karratha gas plant is located 1260km North of Perth and is operated by Woodside Energy Ltd. It produces LNG, domestic gas, condensate and LPG. Woodside was looking for suitably qualified engineering designers to execute the design of kettle type heat exchangers for its LNG Train IV at Karratha gas plant. The design was complex in nature and because of positive past experience Woodside Energy awarded CDMS the design contract.

Project Objectives

Woodside required CDMS to design the heat exchangers to comply with industry standards and also incorporate client specifications, including design of supports for transport.

Challenges

Some of the challenges included the complex kettle shape of the shell and the connections of the heat exchangers. The heat exchangers were connected in pairs
(butted), which affected the design of supports and tube sheets for load transfer, and had to withstand temperatures as low as -46oC. CDMS also had to make special considerations for the design of the external manifold, as the force of the attached piping load onto the manifold was unusually high.

Our Approach

CDMS calculated the combined shell stiffness of various diameters and used this in the design of the tube bundle and tube sheet. The flexibility of the heads was considered in the tube sheet design in order to reduce the load on the tube sheet, resulting in an economic design.
CDMS then developed a complex structural model of two connected exchangers to calculate the support reactions. The nozzle load effects were renegotiated in conjunction with the client, which resulted in an economic but safe design.
The external manifolds were designed as per industry piping standards using pipe flexibility analysis.