The aim of this project is to assess various novel technologies for the valorisation of this coffee waste into further fuels and chemicals. This will be divided into four key objectives.

In the first objective, the hydrothermal carbonisation process (HDC) will be used to convert coffee grounds into a solid carbon rich fuel, a gas and an aqueous phase containing N, P and other microelements. The process will be optimised through the ramp rate, temperature, solids loading, coffee type and other processing parameters on the batch lab scale. The solids and aqueous phase produced will be analysed for elemental composition, calorific value and molecular structure.

On optimisation of the lab conditions a scoping study will be undertaken to recommend the best scale up technologies, suited to the Bio-Bean processing plant in North London. This will include an estimated energy and mass balance as well as recommendations on the upstream and downstream processing, suitable reactor design and estimated economic impacts.

On completion of the assessment of HDC, we will assess a range of technologies to extract lipid from wet biomass under solvent free conditions. The techniques investigated could be particle explosion/implosion techniques, vortex separations technology or homogenisation followed by an emulsion disruption stage. This will form a key stage in the biorefinery, producing a lipid product prior to the HDC process.
In addition to these key bulk fuel products coffee is well known to possess a range of terpenoid, sterol and other target compounds of interest to the pharmaceutical industry. In this work package the coffee waste will be hydrolysed under varying conditions and the solubilised fractions analysed by HLPC-MS to determine likely high value chemicals suitable for further extraction. This will assess whether higher value products are present in the coffee waste, which could be used as a suitable income stream prior to the HDC / briquette process.