At the LNG 15 Conference in Barcelona, Spain, Shell Global Solutions Executive Wiveka Elion said in a presentation that the Anglo-Dutch company's answer to the projected LNG shortfall was to build new Trains more than twice as large as the current 5 MTPA optimum.
Elion said Shell believed, along with many others in the industry, that the projected growth in LNG markets would translate into a demand for larger train sizes.
This was primarily driven by economies of scale in terms of equipment costs, construction costs and project management, she said.
Shell also presented a new design for a Train to produce LNG at a rate of about 11 MTPA, which would be the largest ever built.
The design is based on Shell’s Parallel Mixed Refrigerant process and includes CO2 and sulphur treating, and will be flexible to reach heating values down to typical US specifications, Elion said.
Using large yet fully developed and proven gas turbines, and other key equipment, maximizes economies of scale, she added.
For the 11 MTPA Train, steam is used to integrate heat generation and demand plant-wide, she said. This includes the waste heat recovery from the gas-turbine drivers, co-firing, and heat demand of the energy intensive treating train and heat production by the sulphur-recovery unit.
Under the new Shell Train design, the heat recovered is utilized for process heating and to produce mechanical and electrical power.
The full utilization of waste heat from the gas-turbine exhausts enables a step-change in plant efficiency and reduces the specific CO2 emissions considerably, compared to conventional LNG plant design, she explained.
She said the very large Shell LNG train will have the following characteristics: capacity of 11 MTPA; economies of scale both with respect to capital as well as operational costs; proven equipment; high availability, provided by the steam driven propane compressor; and fuel consumption some 30 percent lower than open cycle based designs.
The key to achieving this is the ability to assess and utilize the full capabilities of, in particular, rotating and heat exchange equipment, she added.
Secondly, a full understanding of the complete process, including treating and LPG extraction, is required to provide optimal heat recovery. The start-up and operation of this large plant is comparable to conventional designs.
The designs of the waste heat recovery and electrical system need to be robust against start-up and trip scenarios, Elion added.
"While absolute costs are difficult to predict in today’s overheated contractor market, we are utilizing full economies of scale for all equipment items. At the same time, care has been taken not to rely on a single vendor for any of the equipment," Elion said.
"The high efficiency of the PMR design makes optimal use of expensive turbine power to generate LNG.
"This design for an 11 MTPA Train represents another major technology step that will meet the world’s need for LNG in the coming decades," Elion concluded.
