Project Description

Decarbonation: 480 tons of CO2 saved based on an emission rate of 0.201 kgCO2/kWhth consumed

Energy savings: 2,400 MWhth saved per year

Location: Pontigny – Burgundy Franche Comté – France

Customer: Wienerberger

Sector: Ceramics – Tilery

Needs – customer requests:

The client wanted to find a way to optimize the waste heat from 6 furnaces in a unit that produces more than 95% of the site’s output. The presence of 6 dryers in a building nearby has allowed us to consider a valorization on these processes.

The objective is to ensure the necessary heat supply to the dryers by the valorization of waste heat.

Project progress:

Analysis of :

  • Deposits: 6 furnaces
  • Requirements: 6 dryers
  • Constraints of on-site installation and remaining fume extraction.

The characterization of the deposits/needs allowed to foresee a solution of heat storage via a pair of Eco-Stock® in order to be able to restore it at the level of the dryers. The chronograms of the ovens and dryers are not synchronous, so the Eco-Stock® solution allows to shift this heat restitution and to adapt it to the need.

This also avoids the need to change production programs.

Eco-Tech Ceram achievements :

  • Study of the chronograms of the cooking ovens and identification of the periods of the cooking cycle where the fatal heat is higher than 350°C.
  • Writing PFD/PID
  • Takeover of the oven hoods (design and manufacture)
  • Proposals for solutions in terms of process control
  • Sizing of an Eco-Stock® solution: storage capacity of 2.3 MWh per tank
  • Thermal and aeraulic study on the smoke network
  • Energy and environmental balance
  • Proposal for a third-party financing solution
  • Design of the solution for the capture and recovery of waste heat

Description of the proposed solution:

Valorization of waste heat from the 6 furnaces of the UP2 to the dryers of the UP2, through a ceramic storage. The implementation of this solution can save up to 2,400 MWhf

Detailed description of the proposed solution:

The fumes are recovered by a spigot on the chimneys of each furnace. The management of smoke evacuation will be modified to have a controlled dilution and no longer passive. This dilution will be regulated on the temperature of the fumes at the furnace outlet, in order to ensure a recovery temperature lower than 600°C.

Dampers will be installed on the stack downstream of the spigot and on the spigot to allow isolation of the equipment from the implemented solution. The existing control devices on the furnaces (pressure sensors), air curtains and dampers will be maintained, so that the operation of the furnace will not be impacted.

The flue gas is sent to the Eco-Stock® and stored. A pair of storage units is positioned, allowing simultaneous charging and discharging to optimize recovery.

To unload the Eco-Stock®, ambient air is sent in counterflow.

The discharged heat is used to feed the different chambers of the dryer, replacing the burners. The air network of the dryer is almost not modified, only a spigot is made on each chamber downstream of the existing burner and upstream of the injection in the chamber to inject the hot air of the Eco-Stock®.

The burners and combustion air supply fans remain in place but are only switched on in case of malfunction of the recovery solution. The Eco-Stock® discharge flow is regulated to maintain the same mixing temperature (air injected into the chambers).

This solution was studied in the case of two production volumes, A and B. The objective was to achieve a dimensioning compatible with both cases so that the recovery solution works independently of the evolution of Wienerberger’s activity.

The technical data are therefore identical for both cases, but the evolution of the economic and environmental data is indicated whenever necessary.