Energy recovery from soda production

Prize: 20,000€

Status: completed


CIECH, a leading European soda manufacturing company, is seeking to recovery heat/energy from synthetic soda production process, in an effort to contribute to the circular economy.


The challenge

The soda manufacturing process is intensive in energy and water consumption.

For each ton of produced soda there is up to 8 m3 of post distillation slurry released which means a stream of around 800 m3/h. The slurry consists of non-soluble calcium salts as well as dissolved calcium and sodium chloride. The temperature of the stream is usually in the range of 100-115 degC.

It is not feasible to re-use the low-heat stream in existing processes. Moreover, standard heat exchanging technologies seem to be non suitable due to the fact that part of the dissolved inorganic salts will precipitate upon cooling. The combination of those two factors calls for an innovative solution to usefully capture the energy from the waste.

See temperatures of the process on the attached annex.

For the basic calculation, please consider:

  • Fuel price: 58 €/t
  • Considered PCS (Net Heating value) of this fuel: 21.5 GJ/t
  • The average cost of electricity: 65 €/MWh


What the client is looking for 

We are looking for solutions which allow the recovered energy to be utilized in:

  • electricity generation
  • conversion to cold / powering cooling systems
  • re-use in soda manufacturing process

The client is willing to economically recover the maximum energy from post distillation slurry to be used at the site, at a lower cost compared to the cost of energy from the network. This must be achieved with a minimal investment.


Evaluation criteria 

All proposed solutions will be evaluated by the following criteria:

  • Technical feasibility.
  • The highest volume of material used (partial volumes will be also evaluated)
  • The best Business Case (the lowest operational cost and the highest value) 
  • Investment required (maximum 10 years recovery)


This is a 2-round tournament with the following submissions:

First round

A PDF document including:

  • Brief description of the proposed process.
  • Types of equipment that will be used.
  • High level business case (investment cost and recovered water cost/m3)
  • Feasibility evidence of the solution.
  • You can add attached document to support your solution

Second round

  • Detailed process
  • Commercial equipment if needed
  • Detailed business case (project implementation, investment cost and recovered energy cost/kW)



This is a 2 round tournament with the following timeline:

1st round – 6 weeks + 4 weeks for evaluation

2nd round – 3 weeks + 2 weeks for evaluation


Supporting information

Annex with:

  • Soda production flow diagram
  • Post distillation slurry (Liquid phase) composition (%)
  • Post distillation slurry (Solid phase - dry) composition (%) 
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