Custom-Hoist With Specialized Rope Drum Gets Job Done on Challenging LNG System

There is no simple catalog solution for hoists on LNG systems. Since the requirements vary depending on the pump manufacturer, plant manufacturer, EPC contractor and country of destination, customers benefit from reliable and customizable products that STAHL CraneSystems can provide. One example of STAHL CraneSystems’ unique abilities is a custom-designed hoist with special rope drum for maintenance cranes on Chinese LNG tanks, built to fulfill the requirements of the Chinese market. The explosion-proof LNG wire rope hoist is based on the tried-and-tested SH ex series, while the rope drum is a mixture of drums from the SH and AS series. 

No LNG tank without crane technology
Shenzhen LNG is the third Chinese LNG terminal, after Ningbo and Tianjin, for which STAHL CraneSystems has supplied explosion-proof crane technology to the plant manufacturer, TGE Gas Engineering. The successful collaboration between the two German firms has already proven its worth in numerous other LNG and gas plants in Europe and Asia – and this was no exception.

The new LNG terminal in Shenzhen consisted of four 160,000 m³ liquefied gas tanks and was commissioned towards the end of 2015. Every LNG tank was equipped with a crane to place the liquefied gas pump on the bottom of the tank and lift it out into the open air again for maintenance or repair work. Due to the potential explosion risk from evaporating gas, all electrical components had to be constructed with an explosion-proof design, which also applies to the crane technology used. In addition to this, further and stricter requirements than those in ATEX or IECex standards must be met in LNG applications, depending on the operator and country of use.

Almost standard, but still exceptional
The specifications for LNG wire rope hoists in Chinese plants require a ratio between rope diameter and rope drum diameter (D/d ratio) that cannot be achieved with a standard hoist. STAHL CraneSystems developed rope drums with a larger diameter specifically for these wire rope hoists and deployed them successfully on the gas tanks at the Ningbo LNG and Tianjin LNG terminals.

The rope, which is firmly connected to the LNG pump, measures 13 mm in diameter. The standard diameter of the drum of the SH 6 wire rope hoist is 356 mm. A drum from the larger wire rope hoist series AS 7 with a diameter of 456 mm is welded on to this drum in STAHL CraneSystems factory to increase the already very good D/d ratio from 27 to 35 without complex modification of the design of the series hoist. At the same time, it is possible to fulfill the customer’s requirement for an additional rope drum brake based on the proven module system of the SH series by using the standard drum and standard frame, resulting in an economical solution in spite of all the modifications.

Long-term reliability
The advantages of near-standard special solutions such as these LNG wire rope hoists are obvious. The individual components stem from our own serial production, their technical design is well-conceived and fully developed, and a supply of spare parts is ensured for the long term. The period of use is difficult to estimate, especially in the case of energy plants and offshore solutions as oftentimes the calculated period of use is exceeded and systems are used significantly longer than planned. The durability, reliability and safety of the crane system can only be guaranteed over the long term if all important components are easily accessible for maintenance work and spare parts are quickly available.

A strong team
TGE Gas Engineering GmbH was responsible for the planning, design and construction of the LNG tanks. The Bonn-based company has erected numerous liquefied gas plants around the world in the last 30 years and has used explosion-proof hoists and crane technology from STAHL CraneSystems in many of these projects. STAHL CraneSystems is known internationally as an expert for customized hoist solutions and as one of the world’s leading manufacturers of explosion-proof crane technology, particularly for the oil and gas industry.