The facility, which produces electricity, heating and cooling, it is the main supplier of power and water to the Synchrotron Alba.
To get in deep with the plant, the installation reduces energy sources and CO2 emissions by up to 35%, just for being the generation close to the consumption point, for the losses during the transport from large power plants to the point of use.
The composition of the cutting-edge technology plant are:
- 3 cogeneration engines (Jenbacher) (part of GE) of 3.33MW
- 2 absorption refrigeration machines
- 1 natural gas recovery boiler
- 1 electrical refrigeration machine
- 1 backup cold-water tank can hold up to 4.500 m3
To get constant the pressure at 16 bars in the inlet gas of the engines, for its properly functionality. The system uses a Gas Pressure Regulating and Metering Station, also called RMG, similar as it is shown in Figure 4.
This RMG includes;
- gas filters (to avoid particles which can damage the pistons of the engine),
- a gas pressure regulator valve,
- in some cases, a compressor, if the pressure is low to the inlet point of the RMG than is required in the outlet,
- a flow meter and the chromatograph, just to know the calorific* value of the gas.
Hereinafter, the RMG must guarantee a constant flow and pressure of the natural gas to feed the engines, because, the flow and pressure can suffer changes, depending if the gas is coming from reservoirs (Liquid Natural Gas, also called LNG), or directly from the pipeline.
In the case of pipeline, there are higher possibilities to suffer variations in the flow and pressure of the gas, which can affect the proper functionality of the engines, increasing the number of corrective maintenance interventions in the engines.
In addition, it is mandatory meaning that for avoiding any possible leakage of natural gas in the high pressure RMG installation (> 16 bars), after the assembling process of the pipes, it is necessary to check the welding of the pipes by radiography test, for the safety of the installation.
Figure 4_Exemple of Gas Pressure Regulating and Metering Station (RMG)_source: J. Sánchez Ríos.
Coming back to the gas engines, the electric yield by gas engines supplies 6.5 MW to the grid. In concrete, to one substation close to the plant (To Endesa Utility), and 3.5 MW of electricity to the synchrotron.
To integrate the electricity by the gas engines yield, it is crucial to get the synchronism conditions, in terms of module, phase, frequency and voltage between the three generators of the gas engines and the electric grid. If those conditions are not met, it is feasible to create damages in the generator, or to create a variation in the voltage or frequency in the grid.
Furthermore, the exhaust air from gas engines, at 400ºC, it is used to heat water and to insert it into the two absorption machines to supply with cold water the synchrotron Alba, and the own polygeneration plant for cooling purposes of the systems of the plant (engines, etc.).
Figure 5_In the left, side view of the 3.3 MW Gas Engine for the supply of electricity and heat. In the right side, view of the natural gas recovery boiler of 5 MW, with its temperature isolate layer, system used as a backup in case of non functionality of the gas engines (see the left side of the Figure 3 of the Polygeneration plant, three gas engines on the bottom, and a natural gas recovery boiler on the top )_source: J. Sánchez Ríos.
Notwithstanding the exhaust air is used to supply the adsorption machines, and those adsorption machines are cooling the water that after is feeding the Synchrotron for the cooling needs.
This water is in a close circuit (see blue colour of the Figure 2), that means. it is not in contact with adsorption machines and not in contact with the Synchrotron directly (only by temperature exchangers).
In the water close circuit, the water is sent by 35 water pumps from the Polygeneration to the Synchrotron at a temperature of 4ºC (Celsius), and is coming back, from the Synchrotron, at a temperature of 13ºC.
Just as information, the water through the circuit must be changed every year. If not, when there is a high level of impurities, the thermal losses are increasing, and then, the system losses thermal performance.
Normally, the thermal losses in the water transport are close to 5-10%, a relatively low percentage, considering, that even the valves are isolated with a thermal layer (Thermal layer shown in the Figure 9).
* The natural gas is not billed by volume or weight, it is measured as energy magnitude. Accordingly, it is depending of the Calorific Value (CV). The CV is different depending of the origin of the gas, for example, the Russian natural gas and the Argelian gas have different CV.
Most of northern and central European countries are supplied by Russian Gas, in the meanwhile, southern European Countries (Spain and Italy) are supplied by natural gas from Argelia.
References:
- ST-4 Polygeneration Plant - Parc de L'Alba
- cogeneration engines (Jenbacher)
- Composition of natural gas consumed in Europe
- Radiography test for gas pipelines by RTD Applus
Index terms:
Polygeneration, Synchrotron, electricity, heating, cooling, power, water, energy, installation, CO2 emission, cogeneration engines, Jenbacher, GE, absorption refrigeration machines, natural gas recovery boiler, electrical refrigeration machine, cold-water tank, pressure, bars, Gas Pressure Regulating and Metering Station, RMG, gas filters, pistons, gas pressure regulator valve, compressor, flow meter, chromatograph, calorific value, natural gas, flow, pressure, Liquid Natural Gas, LNG, pipeline, corrective maintenance, leakage, welding, radiography test, electric yield, MW, grid, substation, Endesa, Utility, synchronism, module, phase, frequency, voltage, exhaust air, exchangers, thermal layer.
J. Sánchez Ríos
javier.sanchezrios.1978@ieee.org
