High Firing Temperature GT36 H-Class Low NOx Combustor Engine Validation and Performance

In order to minimize the footprint of human activities on the environment, technologies to reduce greenhouse gases while meeting constantly growing electricity demands are critical. Amongst the various sources of energy production, Gas Turbines (GT) are an efficient way to stabilize the grid with regards to renewable sources like wind and solar energies. The demand for higher efficiency, higher power output while reducing emission levels (especially NO and NO2) at high loads, and for higher flexibility within the H-class Gas Turbine market is thereby a natural consequence. The development and validation of a two-stage sequential combustor, so-called Constant Pressure Sequential Combustion (CPSC) system, to achieve these goals has been accomplished by Ansaldo Energia. The CPSC consists of a premix burner system (First Stage) and of a sequential burner (SB) in series within a can combustor. At the 2017 and 2019 ASME conferences, high pressure test rig validation results of the CPSC were introduced. The advantages with regards to fuel flexibility, hydrogen combustion and low emissions at high firing temperature were presented [1,2,3,4,5]. This article focuses on the validation of the combustor performance in Ansaldo Energia’s Validation Power Plant located in Birr, Switzerland, which includes detailed validation from ignition to full speed no load, part load operation and full load over various ambient and engine thermal state conditions. To allow for detailed validation, dedicated fully instrumented combustor cans were installed in the GT. Detailed validated air distribution and emission models support the results obtained on the engine. Ignition and ramps up to full speed no load have been validated with large variations of the first combustor stage firing temperature to minimize power consumption and start-up time. The potential of the CPSC with regards to turndown capability, with minimum environmental load (MEL) below 25% GT load while keeping CO levels low has been confirmed. The MEL can be kept low over a wide range of ambient temperature and fuel compositions by adjusting the inlet temperature of the sequential burner. Low NOx values were achieved at baseload and peak firing temperature. The operational flexibility and stability of the premixed first stage combustor over the load range and over a large variation of combustor inlet plenum pressures was as well validated along with the operation concept of the gas turbine.

Research on Drying Sludge in Brick Making

Dried sludge could be used for brick production by firing with shale or clay, which would reduce clay resource exploitation and realize sludge resource utilization. Physical and mechanics parameters of fired shale-sludge brick and clay-sludge brick are tested to examine technical feasibility, and heavy metal leaching concentrations are tested to examine brick safety. The results show that after municipal sludge in Changsha Wastewater Treatment Plant is dried with water content no more than 30%, it can be used for shale-sludge brick and clay-sludge brick firing and qualified produces can be produced. Compressive strength of brick is 10-20 MPa, there is no scum and lime crack on brick body. Under high firing temperature, heavy metal in sludge can be solidified, and leaching concentrations can meet the requirements. By doing so, calorific power of sludge can be utilized and energy saving can be realized.

The Study on the Energy-Saving Technique of down Draft Kiln

The down draft kiln which uses producer gas as fuel generates high-temperature waste gas, wasting a lot of energy and making it difficult to get high firing temperature. Based on the theory and experiences from practice, herein we propose a set of methods aiming at improving the energy efficiency of the kiln. The methods include: directly heating raw materials using the high-temperature waste gas from the kiln; changing the location of combustion chamber from the bottom to the top of the kiln; modifying other aspects (such as the numbers of kiln, the location of kiln and flue). The validity of these modifications was verified by an industrial experiment. It was demonstrated that with same size of kiln, the productivity of a kiln used for firing bauxite increased by more than 30% and the fuel consumption was reduced by more than 16%.