(87e) Automated Switch-Over Between Transfer-Line Valve & Decoke Valves

Linde Engineering uses an automated system to switch from operation through the transfer-line to the decoke line and vice versa. The first system of this kind was installed in 2000 and has been working to satisfaction. The same system was installed for three other clients in Europe and it is currently our design of choice.

The actuators of the transfer-line valve and the decoke valve have a software linkage and a key interlock system, but not the traditional direct mechanical linkage between the valves or actuators. Differential pressure controls ensure that the valves act as non-return valves, providing an additional level of safety.

The paper will stress the functionality and the safety principles of the system, resulting from the HAZOP performed for the various projects.

The paper will also provide details of the design as well as operational data. There will be a step by step description of the actuator and valve sequence as well as sequencing of the key interlock system and logic description. Mechanical lay-out of the valves and actuators will also be addressed as well as developments from the traditional gate valves to modern metal seated butterfly valves.