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Sustainable Production of Industrial Recovered Energy using energy dissipative and storage technologies

Periodic Reporting for period 2 - SUSPIRE (Sustainable Production of Industrial Recovered Energy using energy dissipative and storage technologies)

Reporting period: 2017-04-01 to 2019-09-30

This project has focused its activity on residual heat streams that can be classified by their physical condition: liquid, solid or gas and by the temperature range that they have. This project has identified investment casting manufacturing process with its corresponding residual heat streams as representative of a significant number of energy intensive industries such as steel, glass, cement, food industry. Identified residual heat streams are basically:
• High temperature exhaust gases from combustion furnaces that are generated in a continuous way. Exhaust gases get out from the furnace at around 800ºC.
• Steam getting out of the boilerclave at around 100ºC and that is discontinuously generated.
• Cooling water from different equipments such as: Wax injection units, compressors, induction furnaces.

Different technical solutions have been identified in this project :
• Innovative High Temperature Heat Exchanger (HTHE) for energy recovery from combustion gases allows recover heat directly from high temperature source up to 800 °C. The design of the HTHE is based on innovative so called “pillow-plate” heat exchanger. This solution allows to ensure even thermal contact between hot chimney wall and heat transfer fluid (Syltherm 800 is used). Also channels of pillow-plate type heat exchanger distribute the HTF evenly through heat transfer area. Internal geometry of HTHE is design to ensure a large heat transfer area and minimize pressure drop of exhaust gases without affecting furnace operation.
• Innovative design of High Temperature Heat Exchanger with integrated inorganic PCMs heat accumulator (HTHE PCM) allows the heat exchanger to operate in charging or discharging and direct heat transfer (between two fluids in two independent loops) modes simultaneously when the consumption and supply modes do not match and/or the heat transfer rate of charging and discharging differs. Inorganic PCM (H190) store heat at constant temperature up to 350 °C.
• Innovative design of Low Temperature Heat Exchanger with integrated organic PCMs heat accumulator (LTHE) allows achieving a high heat recovery and storage rate – high quantity of heat in a brief period of time can be recovered and stored. The system consists of two independent loops connected by copper plates (fins). The heat exchanger can operate in charging or discharging and direct heat transfer modes simultaneously when the consumption and supply modes do not match and/or the heat transfer rate of charging and discharging differs. Organic PCM (RT82) store heat at constant temperature up to 100 °C.
• A BTES system has been developed placing a total quantity of 30 bores of 150 meters depth for heat interchange with the ground and taking advantage of the storage capacity. This system gathers the energy of the High Temperature circuit onde its temperature is lower than 50ºC to be used all the remaining energy in cascade. The system is supported in a heat pump that supplied heat or cold depeinging on the needs but always considering the differential temperature achieved in the ground.
• The process main data variables are controlled by a smart data management system that will achieve the best energy recovery yield maintaining or improving the manufacturing and quality ratios

These technical development have led to following industrial results:
- The total energy recovery rate has been 8022 MWh/y of primary energy. We have to rest associated consumptions of the energy recovery system (pumps and heat pump) 1890 MWh/h. Net savings are 6131 MWh/year that supposes an energy reduction consumption of a 15,9% of the total plant consumption. The recovery rate was initially forecasted with a lower energy consumption of the plan (4222 MW/h/y), now the quantity has increased but the percentage is lower.
- LCA mainly as CO2 emissions reduction has been calculated representing a 22% reduction.
- A signature with PCB has been made agreeing the terms of commercialization of the excess of energy with TELUR and the town council will launch a tender for energy supply to the sports center in brief.
- The energy consumption of natural gas of the sport centre is aroung 3 GWh/y, and the forecasted supply of energy with the final results obtained is 1539 MWh/y in thermal energy, and 2012 MWh hvc /y in natural gas, so the saving for the sport centre is:3000 – 1539 = 1461 MWh hvc/y (49%)
This project report includes all the project period from the beginning to its closure after 48 month running.
During this working period corresponding to the 48 months WP1, WP2, WP3, WP4, WP5, WP6 and WP7 have been finished and final results from performed activities are as follows:

• R1 - A group of new heat exchanger equipment (2 prototypes): one for high temperature heat exchange and another for low temperature heat exchange will be developed.
• R2 - A Borehole Thermal Energy storage unit (BTES) with two different levels of heat storage will be developed
• R3 – Expert knowledge on PCM selection, integration and use including equipments construction and safety measures
• R4 – Expert knowledge on Heat Transfer Fluid for high energy recovery exhaust gases (800ºC) selection, integration and use including equipments construction and safety measures.
• R5 - Smart Management System, with an adapted methodology for process monitoring and control, to be integrated in the ISO 9100 of the plant.
• R6 – Energy savings due to running energy recovery system
• R7 – Industrial system for energy recovery.

The dissemination has taken place over different congresses and fairs StatusPrediction of lifetime of critical components for energy efficient installations /Tribology International/Lubmat (C) 2016/International Conference “Environmental Engineering”, Vilnius, 28 April 2017/ Geoner 2017 V Congreso de energía geotérmica aplicado a la edificación y a la industria , Madrid, 26 Abril 2017, Energy day Durango 2018, GIFA Düsseldorf 2019
Actual plants have several handicaps to integrate this type of systems as in their lay out energy recovery of industrial heat streams has not been an objective. This project aims to be a reference to systematically integrate the products, equipments and smart control systems that will be developed in an industrial plant with intensive energy consumption. A future challenge could be to apply the technology and methodology developed as part of the manufacturing process.
The contract signed off with third parties assure a symbiosis between industry and society and support the sustainable development of process industry in the surrounding areas.
Heat exchangers with a high accumulation capacity rate can be extrapolated to other segment niches as exhaust gases in the transport area where energy can be stored and further used in for fuel preheating or transferred for external applications.
Industry with less intensive energy consumption, but with local generation of this residual heat streams, can also take advantage of these new technologies due to be more affordable by their development in the market. The PCM resulting from this project will open the window for new business by formulating and commercializing these products.
SusPIRE project has developed a smart data management system that will define the best actuation protocols at any time for a given process to reduce rejection rate as an additional residual heat stream.