LESER Update May 2022

Sales project in Mexico: Compelling service quality

The new Dos Bocas refinery is expected to make the North American country less dependent on fuel imports. LESER supplies safety valves adapted to local needs.

2018, the Mexican government decided that the national oil company Petróleos Mexicanos (PEMEX) will build a new refinery near the port city of Dos Bocas. It is located about five kilometers to the north of the city of Paraiso in the southern Mexican state of Tabasco. The refinery is part of the country’s “National Refinery Plan”. When completed, it is expected to produce around 340,000 barrels of fuel per day, making it the largest refinery in the country. Despite its large oil reserves, Mexico currently has to import about 75 percent of its fuel requirement. By building its seventh refinery in Dos Bocas, Mexico wants to reduce its dependence on these imports. PEMEX has contracted two EPCs, ICA Fluor and Techint, to build petrochemical equipment for the project. LESER had trained both EPCs on the use of safety valves for overpressure protection two years ago.

A solution for challenging specifications

In the meantime, an intense process of technical preparations involving more than 100 bids and technical revisions took place. At the end, LESER was contracted for more than half of all safety valves to be used in the Dos Bocas refinery. LESER was able to overcome special engineering challenges, such as providing crude oil overpressure protection involving a measuring line more than 150 meters in length. The LESER engineers developed a solution based on the additional electropneumatic load.

Another reason LESER was chosen: The safety valve specialist meets the unique Mexican service requirements,

  • including being able to supply full documentation in Spanish.
  • The safety valves will be re-tested based on customer specifications, and commissioned at the refinery by LESER and its Mexican partner Rawson Mexicana (a LESER Authorized Repair Center).

According to current plans, the Dos Bocas refinery will enter its startup and trial stage in late 2022/early 2023, and full operations are to start during the year 2023. Products from the “Home of Safety Valves” will be protecting the plant against overpressure.

Sales project in Germany: Delivering extra closing pressure

Supplementary loading system for high back pressures at DESY in Hamburg.  

The German research institute Deutsches Elektronen-Synchrotron (DESY) needed to lower the operating pressure for helium containers used to cool its electron accelerator. However, it was impossible to proportionally reduce the back pressures occurring in the pressurizer relief system. As a consequence, the existing spring-loaded safety valves were unable to handle the back pressure conditions which were as high as 60 percent. Since the set pressure is only 0.5 bar, using standard bellows-type or pilot-operated safety valves was not an option. What is more, the helium system must be protected at extremely low temperatures of -273 °C. Yet another requirement was to keep modifications of the existing system arrangements to an absolute minimum.

Selecting the right solution from a large range of configurations

LESER proposed its Supplementary Loading System (SLS) as a solution for DESY’s challenge and was awarded the contract for the project. Fitting a SLS to a spring-loaded safety valve provides additional closing pressure. The solution consists of a pneumatic piston that serves as an extension of the spindle and compresses air to apply extra pressure. Under normal operating conditions, this pressure, in conjunction with the spring, counteracts the operating pressure acting on the disc from below.

By delivering increased closing pressure, supplementary loaded safety valves provide greater tightness: They remain tight up to the set pressure. This allows the respective plant to operate at a higher system pressure. When the valve is triggered, the lower differential release or blowdown pressure allows it to open for a shorter period, reducing loss of media. “We are really happy about the solution we selected with LESER,” says Dieter Mross who is in charge of the project at DESY. “With very few modifications we have been able not only to adapt the existing plant but also to improve it significantly.”

Configuration details

  • LESER Type 441 safety valves in sizes DN 25 through to 250
  • Several LESER Type 712 add-on Supplementary Loading System
  • Protection of a helium cooling system for the electron accelerator with extremely low operating temperatures of -273 °C, high back pressures of 60%, and a low set pressure of 0.5 bar