As early as 2013, a total of 40 process diaphragm pumps were delivered to two large offshore platforms on the Persian Gulf for the purpose of pumping approx. 70 million cubic metres of natural gas per day and producing about 50 million cubic metres of gas that is ready for sale. The order, worth around 30 million euros, was the largest in the history of Lewa at the time–and then the follow-up order was placed in the summer of 2017: A total of eight LGB2 Boxer pumps and 12 LDH5 series process pumps have been ordered for transferring monoethylene glycol (MEG) from the Tie In Platforms (TP) to the Well Head Platforms (WHP) and on-site MEG injection. This injection is intended to prevent the ice formation in the drill hole that can occur during the formation of methane hydrate. The project will be completed in 2019.
The plant, which was built in 2013 and has been the largest of its kind in Saudi Arabia ever since, has now been expanded to handle having its daily gas flow of 70 million cubic metres increased by another 56 million cubic metres. "A fundamental goal of the client is to gradually convert the energy utilities of the country from crude oil to gas in order to make more crude oil available for the global market" explains Klaus Figgle, Engineering Project Manager at Lewa.
The eight LGB2 Boxer pumps with the corresponding M9 pump heads were installed on the Tie In Platforms (TP). They are responsible for transferring monoethylene glycol (MEG) to the Well Head Platforms (WHP). The LGB2 pumps operate with a relatively low pressure of about 205 bar, since they only have to overcome the drop in pressure in the supply line between the platforms. The LGB modular drive unit, which has already been used as an LGB3 model for the preliminary project, stands out for its compactness and very high power density.
WEG Germany GmbH was acquired as a cooperation partner for the project. The order was processed as the first major project involving WEG as a powertrain manufacturer. The custom-designed powertrain solution consists of energy-efficient motors and complete control cabinet systems with integrated frequency inverters–ideal for offshore applications. WEG, one of the largest global electric motor manufacturers, has the necessary approval of the end client for its plant in Brazil.
The twelve LDH5 series injection pumps, with corresponding M8 pump heads, consist of five coupled single powertrains. "Similarly to the preliminary project, the MEG continuously circulates between the platforms and the glycol regeneration units in the onshore preparation plants," Figgle continues. "In the process of preventing methane hydrate accumulation, our injection pumps inject the MEG at the necessary points to eliminate ice formation in the drill holes. In addition to the pressure drops in the lines, these pumps must also overcome the back pressure from the source, which is why pressures of up to 600 bar must be expected."
The M8 pump heads installed for this purpose are equipped with PTFE diaphragms, which can handle even high pressure without problems, and offer further advantages when compared to the originally required metal diaphragms. Since pumps with metal diaphragms are usually larger and heavier, Lewa offered the PTFE diaphragms to provide the client with a solution which–in addition to space and size advantages–also resulted in a reduction in the production costs of the entire platform. Lewa is the only company in the world qualified to supply pumps with PTFE diaphragms for the end client in Saudi Arabia, which are designed for a pressure of over 350 bar.
"This solution, developed specifically for the application, was completed smoothly by all parties involved and delivered on time," Figgle says to summarise. "On the whole, all sides have been very pleased with the project. It will be handed over to the client in 2019."