Mass Balance Allocation Audit Mechanics in Depolymerized Monomer Supply Chains
Depolymerized monomer mass balance audits verify physical yields and loss factors because laboratory testing cannot distinguish recycled from virgin monomers.
Feedstock Moisture Allowance
Material Specification
Commercial purchase agreements for textile waste feedstocks specify the permissible water content in delivery lots. The feedstock moisture allowance establishes the standard water percentage above which the buying mill applies financial penalties or rejects the shipment. Synthetic polymer recycling mills demand dry polyester scrap because water weakens the chemical breakdown process.
This baseline limit prevents mills from paying for water weight instead of usable polymer flakes.
Mill Inspection
Moisture testers measure incoming bales of compressed polyester garments upon arrival at the recycling yard. The feedstock moisture allowance is enforced by taking core samples from multiple points in each delivery container. If the average moisture exceeds the set limit, the mill recalculates the net dry weight of the shipment.
This weight adjustment directly reduces the payment to the supplier, ensuring that the mill only pays for dry plastic.
Reactor Protection
Water in recycled plastics causes catastrophic hydrolytic degradation when heated in continuous reactors. Above the feedstock moisture allowance, the steam generated by trapped water creates rapid pressure spikes and breaks the polymer chains too early. This leads to low-viscosity polymer melts that cannot be extruded into textile fibres.
By drying the scrap fabric below the allowance threshold, the mill ensures that the recycled polyester matches the molecular weight and tensile strength of virgin polymer.
Contract Boundary
Weather conditions during shipping determine the operational challenges of this raw material check. Damp weather during transit can cause baled garments to absorb water, pushing them beyond the feedstock moisture allowance. For this reason, suppliers must wrap bales in protective film or face financial write-downs upon delivery.
This contract condition protects the buyer from carrying the cost of transit humidity.