# D5.5 Commissioning

Alain Ferriere

► To cite this version:

Alain Ferriere. D5.5 Commissioning. [Research Report] European Union. 2022. hal-04750963

HAL Id: hal-04750963

https://cnrs.hal.science/hal-04750963v1

Submitted on 28 Oct 2024

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POLYPHEM

THE FUTURE OF SMALL-SCALE CSP PLANTS

# POLYPHEM
## Small-Scale Solar Thermal Combined Cycle

## D5.5 Commissioning

Date of delivery 01/09/2022

Author(s) Alain Ferriere

Institution/Company CNRS

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 764048.
## Document tracks

<table><tr><td>Identification</td><td>POLYPHEM_D5.5_Commissioning</td></tr><tr><td>TITLE OF DELIVERABLE</td><td>Commissioning</td></tr><tr><td>Author(s)</td><td>Alain Ferriere</td></tr><tr><td>Reviewers(s)</td><td>Lauriane Gonzalez</td></tr><tr><td>Related Work Package (s)</td><td>WP5: Manufacturing and installation of the prototype plant</td></tr><tr><td>Beneficiary responsible of delivery</td><td>CNRS</td></tr><tr><td>Due date of delivery</td><td>31/03/2022</td></tr><tr><td>Actual date of submission/revision</td><td>01/09/2022</td></tr><tr><td>Number of pages</td><td>10</td></tr><tr><td>SUMMARY</td><td>This document is the deliverable D5.5 of the project POLYPHEM. It is planned in the framework of the Work Package 5 (Manufacturing and installation of the prototype plant).<br/>The deliverable D5.5 reports on the commissioning of the components installed at Themis site as parts of the prototype plant POLYPHEM. These components are: the combustor, the recovery heat exchanger, the thermal oil piping, the ORC group and the thermal energy storage system. The solar receiver could not be delivered. The gas turbine has been commissioned at the test-bench of KAEFER in Bremen (Germany).</td></tr><tr><td>Dissemination level</td><td>PU</td></tr><tr><td>Repository</td><td>https://dms.polyphem-project.eu</td></tr></table>

## Document History and Validation

<table><thead><tr><td>Date</td><td>Name</td><td>Comments</td></tr></thead><tbody><tr><td>28/08/2022</td><td>Alain Ferriere</td><td>Creation</td></tr><tr><td>29/08/2022</td><td>Lauriane Gonzalez</td><td>Review 1</td></tr><tr><td>30/08/2022</td><td>Alain Ferriere</td><td>Final</td></tr></tbody></table>

All information in this document only reflects the author's view. The European Commission is not responsible for any use that may be made of the information it contains.
## Background: about the POLYPHEM project

<table><tr><td>FULL TITLE</td><td>SMALL-SCALE SOLAR THERMAL COMBINED-CYCLE</td></tr><tr><td>Acronym</td><td>POLYPHEM</td></tr><tr><td>Call identifier</td><td>H2020 LCE-07-2017-RES-RIA-TwoStage</td></tr><tr><td>Instrument</td><td>Research and Innovation Action (RIA)</td></tr><tr><td>Grant Agreement N°</td><td>764048</td></tr><tr><td>Starting Date</td><td>01/04/2018</td></tr><tr><td>Duration</td><td>48 months</td></tr><tr><td>Website</td><td>https://www.polyphem-project.eu</td></tr><tr><td>Keywords</td><td>Renewable electricity; Energy collection, conversion and storage; Renewable energy</td></tr><tr><td>Additional keywords</td><td>Concentrated solar power; Solar tower system; Combined cycle; Gas-turbine; Thermal energy storage; Organic Rankine cycle; Process control</td></tr><tr><td>Beneficiaries</td><td>CNRS, CEA, CIEMAT, Arraela S.L., Fraunhofer ISE, Kaefer Isoliertechnik, Orcan Energy, Euronovia, Aalborg CSP</td></tr></table>

The POLYPHEM project is a research and innovation action funded by the European Union's H2020 program. It is implemented by a European consortium of 4 research centres and 5 industrial partners. The aim is to increase the flexibility and improve the performance of small solar tower power plants. The concept of POLYPHEM consists in implementing a combined cycle formed by a solarized micro gas-turbine and a Rankine organic cycle machine, with an integrated thermal storage device between the two cycles. The need for cooling is minimal.

Developed from a patented technology by CNRS and CEA, the pressurized air solar receiver is integrated in the micro-turbine cycle. The thermal efficiency targeted for the receiver is 80% with a cost of 400 €/kW. The innovative thermal storage uses a thermal oil and a single thermocline tank with a technical concrete filler material.

The main expected impact of this project is to enhance the competitiveness of low-carbon energy production systems through the technology developed. The expected progress is a better fitting of electricity generation to variable local needs, an overall conversion efficiency of solar energy into electricity of 18% for an investment cost of less than 5 €/W and a low environmental impact. By 2030, the cost of electricity production targeted by the POLYPHEM technology is 165 €/MWh for an annual direct normal irradiation of 2600 kWh/m²/year (North Africa and Middle East) and 209 €/MWh under 2050 kWh/m²/year (Southern Europe). In addition to decentralized power generation, other applications are considered for the deployment of this technology used in poly-generation: industrial heat production, solar heating and cooling, desalination of seawater or brackish water.

A prototype plant of 60 kWel with a thermal storage of 1300 kWh is designed, built and installed on the site of the experimental solar tower of Themis in Targasonne (France). The objective of the project is to validate the technical choices under test conditions representative of actual operating conditions.

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 764048
## Table of content

<table><tr><td>1. THE PROTOTYPE PLANT POLYPHEM</td><td>5</td></tr><tr><td>2. COMMISSIONING OF THE GAS-TURBINE</td><td>5</td></tr><tr><td>3. COMMISSIONING OF THE ELECTRICAL CABINETS AND POWER SUPPLY</td><td>5</td></tr><tr><td>4. COMMISSIONING OF THE COMBUSTOR</td><td>7</td></tr><tr><td>5. COMMISSIONING OF THE PIPING</td><td>8</td></tr><tr><td>5.1 Commissioning of pumps and valves, 12 -28 April 2022.</td><td>8</td></tr><tr><td>5.2 Commissioning of the thermal oil circuits 3 May-24 June 2022</td><td>9</td></tr><tr><td>6. COMMISSIONING OF THE RHX</td><td>9</td></tr><tr><td>7. COMMISSIONING OF THE TES</td><td>10</td></tr><tr><td>8. COMMISSIONING OF THE ORC</td><td>10</td></tr></table>

## List of Figures

Figure 1: P&ID of the prototype plant POLYPHEM.................................................................................. 6

Figure 2: Scheme of the electrical system of the prototype plant POLYPHEM.................................................. 7

Figure 3: Temperature of the air delivered by the combustor - Example of test result .................................................. 8

## List of Acronyms and Abbreviations

<table><thead><tr><td>Acronym/abbreviation</td><td>Meaning/full text</td></tr></thead><tbody><tr><td>CNRS</td><td>Centre National de la Recherche Scientifique</td></tr><tr><td>μGT</td><td>Micro gas-turbine</td></tr><tr><td>ORC</td><td>Organic Rankine Cycle</td></tr><tr><td>PU</td><td>Public</td></tr><tr><td>RHX</td><td>Recovery Heat Exchanger</td></tr><tr><td>TES</td><td>Thermal Energy Storage</td></tr></tbody></table>
## 1. THE PROTOTYPE PLANT POLYPHEM

The prototype plant POLYPHEM was initially composed of the solar receiver integrated in the gas cycle of the micro gas-turbine, the recovery heat exchanger (RHX), the thermal oil piping and actuators, the organic Rankine cycle (ORC) and the thermal energy storage system (TES).

The structure and composition of the plant has been changed in October 2021, due to the failure in the achievement of the final step of construction of the solar receiver. The construction of this component is reported in details in the deliverable D5.2 *Manufacturing and installation of the solar receiver*, released on 11 January 2022.

The construction of the TES is not finished on 31 August 2022. In order to allow the commissioning of the piping and other components in absence of TES tank, ARRAELA supplied a small expansion tank which was installed on the roof of the container. With this additional component, the thermal oil circuit can be operated safely.

The P&ID of the plant is presented in Figure 1. It is also found in the deliverables D6.1, D4.2 & D4.3.

## 2. COMMISSIONING OF THE GAS-TURBINE

The consortium of the project decided not to install the micro gas-turbine (µGT) at Themis site. This component has been installed, commissioned and tested in the test facility of KAEFER in Bremen (Germany). This action is reported in the deliverable D2.7 *Demonstrator on the factory pre-test of gas turbine package and ORC module*, released on 30 August 2022.

## 3. COMMISSIONING OF THE ELECTRICAL CABINETS AND POWER SUPPLY

The electrical system designed for the power supply of the plant is described in the scheme of Figure 2.

The 'POLYPHEM' cabinet is located inside the container. It is supplied from the existing electrical cabinet 'THEMIS' located at the bottom of the solar tower. 'POLYPHEM' dispatches the power supply to:

* the ORC controller

* the ORC damper

* the burner and its fan

* the electrical heaters of the TES

* the electrical heater of the oil tank

* the 'PROCESS' cabinet

* the 'CONTROL' cabinet

* the emergency stop circuit

* the lightning circuit

The 'PROCESS' cabinet is also located inside the container. It supplies all the actuators (pumps and valves).

The 'CONTROL' cabinet contains the connectors for the measurement and control signals.

The electrical system was commissioned on 8 April 2022. The circuits were successfully tested. The emergency stop and the reset work properly.
<figure><img src="image_6.png" /><figcaption>Figure 1: P&ID of the prototype plant POLYPHEM</figcaption></figure>
<figure><img src="image_7.png" /><figcaption>Figure 2: Scheme of the electrical system of the prototype plant POLYPHEM</figcaption></figure>

## 4. COMMISSIONING OF THE COMBUSTOR

The combustor was designed and manufactured by AALBORG CSP. It was delivered on 7 March 2022 and installed at Themis site on 21 March 2022. A specific fuel pipe was installed by CNRS to supply the burner with fuel from the fuel tank already existing at Themis. The fuel is diesel (non-road gas-oil).

The commissioning of the combustor was done from 12 May to 2 June 2022. For this action, CNRS was assisted by an engineering company specialized in the field of burners. The commissioning consists of controlling the ignition and flame stability, the pressure of fuel and pressure of gas in the flame tube. It was performed in two steps:

1. Installation of nozzles on 12 May 2022 for adapting the rate of injection of fuel to the required thermal power. Two regimes are set: 145 kWth and 322 kWth. The low regime was successfully tested. Unfortunately, a wrong electrical cable connection caused a major damage to the controller when the regime was switched to the high value.
2. The cable connection was corrected and the controller was replaced. The commissioning at full load was successfully achieved on 2 June 2022. The temperature of the air at the outlet of the combustor (mix between dilution air and flue gas from the burner) was stabilized between 200°C and 500°C, according to the power of the burner and the speed of the fan for dilution air. The combined influence of the air vanes located across the mixing zone and of the position of the conical divertor at the outlet of the flame tube was also assessed with specific testing. An example of test result is presented in Figure 3. Finally, the positions of the vanes and of the cone were set to maximize the stability and homogeneity of the outlet air temperature.

<figure><img src="image_8.png" /><figcaption>Figure 3: Temperature of the air delivered by the combustor - Example of test result</figcaption></figure>

## 5. COMMISSIONING OF THE PIPING

The piping has been installed at Themis site from January 2022 to August 2022. The construction of the piping is reported in the deliverable D5.4 *Piping, auxiliary equipment and cables connections*, released on 31 August 2022.

### 5.1 COMMISSIONING OF PUMPS AND VALVES, 12 -28 APRIL 2022.

The main pump P-01 was successfully commissioned on 12 April 2022. The actuator operates properly, the pump rotates in correct direction of rotation.

The recirculation pump P-ORC-01 was successfully commissioned on 12 April 2022. The actuator operates properly, the pump rotates in correct direction of rotation.

The filling pump P-02 could not be commissioned at the same time, because the frequency controller did not operate properly. The assistance of the manufacturer was required to set the parameters of the actuators. This was done on 28 April 2022 and the filling pump was commissioned at that date.
The motor valves EV-01, EV-02 and EV-03 were commissioned on 12 April 2022.

## 5.2 COMMISSIONING OF THE THERMAL OIL CIRCUITS 3 MAY-24 JUNE 2022

### 5.2.1 Cold commissioning: 3-18 May 2022

The cold commissioning of the thermal oil circuits started on 3 May 2022.

The circuits have been filled with thermal oil pumped from the oil tank. The air is correctly evacuated from the pipes through the venting during the filling. Leakages of oil have been detected on a few flanges, and have been successfully solved.

The main pump P-01 was activated to make the oil flow in the circuits. Despite the continuous utilization of the heater immerged into the oil tank, during several days and nights, the temperature of oil remained low (about 15°C) which resulted in small flowrate. Moreover, the flowmeters of vortex type cannot measure the flowrate because of the high viscosity of oil at low temperature (low Reynolds number, not enough turbulence in the oil flowing into the flowmeter). The minimum oil temperature required for allowing the measurement of the flowrate is estimated at 75-85 °C.

The circulation with the P-ORC-1 (recirculation pump) is not correct. The pump suction is high, a depletion is created at suction, air enters in the pipe. The flanges are not supposed to be sealed when depletion is created at the inside. This is due to insufficient pressure loss at the discharge and large pressure loss at the suction, the reference pressure being imposed by the expansion vessel. However, the circulation through the ORC is done. The pressure loss in the ORC is measured around 300 mbar. In full recirculation, the inlet pressure is 0.900 bar, the outlet pressure is about 0.600 bar (depletion). When recirculation is reduced (oil is partly taken from/directed to the TES/RHX), then the inlet pressure decreases down to 0.760 bar (depletion) and the outlet pressure decreases accordingly (0.480 bar). This issue of low pressure in the circuit should be solved when the TES is installed.

The draining of the oil circuit was successfully tested. The oil flows back to the oil tank by gravity.

### 5.2.2 Hot commissioning: 24 June 2022

The configuration of the circuit was a closed loop around the RHX: the main pump P-01 pushes the oil through the RHX and the oil returns back to the suction side of the pump. In this configuration, the thermal oil was continuously heated up.

The oil was progressively and slowly heated by directing to the RHX a fraction of the hot air flow (190°C) delivered by the burner at 145 kWth. The circulation pump P-01 was set to 2900 rpm and was kept constant. The thermal oil was heated up to 110°C in the RHX. The total duration of the test was about 90 minutes.

At the end of the sequence, the parameters in the RHX were:

* Air inlet temperature 187°C, air outlet temperature 96.5°C

* HTF inlet temperature 100.8°C, HTF outlet temperature 113.3°C

* HTF inlet pressure 4.44 bar, HTF outlet pressure 1.23 bar (ΔP=3.21 bar)

The quality of seals and flanges was checked, the result is correct.

The correct indication of the vortex flowmeters was also checked (Reynolds number >5000).

No significant release of steam was observed.

## 6. COMMISSIONING OF THE RHX

The RHX has been designed, constructed and delivered by AALBORG CSP. It is an exchanger tubes and shell. It was received by CNRS at the workshop of the subcontracted constructing company in Perpignan (France) on 3 December 2021. The shell was carefully dried with circulation of pressurized nitrogen during several hours.
The RHX is placed in the container, as part of the air circuit and of the thermal oil circuit. The container was installed at Themis site (Targassonne, France) on 21 March 2022.

The commissioning of the RHX was done simultaneously with the commissioning of the piping. See §5.2 au-dessus.

## 7. COMMISSIONING OF THE TES

The TES consists of a single thermocline storage tank containing the thermal oil and the porous filler bed made of concrete bricks. The construction of the TES is done by ARRAELA and CNRS. It is not finished on 31 August 2022 (see deliverable D5.1 *Manufacturing and installation of the thermal energy storage*, delivered on 31 August 2022).

The commissioning of the TES is scheduled in week #40 (3-7 October 2022).

## 8. COMMISSIONING OF THE ORC

The ORC machine supplied by ORCAN Energy was delivered at Themis site on 28 February 2022, and it was installed on 21 March 2022.

The commissioning of the ORC is not done on 31 August 2022. The construction of the TES is not finished. Consequently, the ORC cannot be tested in all operating modes. Moreover, the recirculation circuit does not work properly (see 5.2.1 au-dessus).

However, the commissioning of ORC in simple operation mode (close loop on the RHX) is scheduled in the week #37 (12-16 Sep 2022).