The continuous increase penetration of variable renewable energy and fuel cost requires steam turbine power plants to operate with high flexibility. Furthermore, the reduction in electricity price is forcing many existing and new district heating power plants to further optimize the heat production to maintain a sustainable business. This situation leads to low pressure steam turbines running at very low volume flow for an extended time. In this work, a case study of an existing 30 MW~el~ district heating power plant located in Europe is presented. The customer request was the removal of the steam turbine last two stages along with the condenser to maximize steam delivery for district heating operations. However, based on the low load studies carried out by GE in the last years, the same heat production has been guaranteed without any significant impact on the existing unit, excluding any major modification of the plant layout such as last stage blading and condenser removal. The minimum cooling flow through the low-pressure turbine has been reduced by more than 90% compared to the existing unit. Optimization of the hood spray system and logic will  reduce trailing edge erosion during low load operation leading to a significant extension in the last stage blade lifetime.

These modifications, known as GE low load package, provide a cheap, flexible and effective solution for the customer.

With today’s knowledge GE has the capability to guarantee low load operation minimizing the mass flow through the low-pressure turbine to the minimum required for safe operation. As a benefit to the customer, this option allows a gain in operational income of about 1.5 M€ per year.

The development of this product has been enabled by a PhD study funded by GE on steam turbine flexibility and low load operation and the collaboration with the Fluid Machinery and Energy System Laboratory of University of Cassino and Southern Lazio (UNICLAM).  


Application of GE Low Load Package on an Existing District Heating Power Plant: A Case Study

Division / Sponsors: 
Power Division & Nuclear Engineering Division (NED)

Power Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/POWER/POWER2020/volume/83747

International Conference on Nuclear Engineering
Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE2020/volume/83761

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