How to Choose an Automatic Proximate Analyzer for a Commercial Coal Lab

Throughput is a business model, not a spec

A commercial coal lab prices per sample but pays per hour. An automatic proximate analyzer that completes 20 samples — moisture, ash and volatile matter — in 90–120 minutes effectively triples the daily output of a manual two-oven setup, and dual-furnace models let a second batch pre-heat while the first is weighed.

Ask vendors for a batch-cycle diagram, not just a per-sample time. Sample-change interventions, crucible lid handling and cooldown gaps are where cheap analyzers lose entire hours per day.

Weighing architecture: thermobalance vs conveyor

Conveyor-type analyzers move crucibles between a furnace and a separate balance. Every transfer introduces thermal disequilibrium and drift. Thermobalance designs keep the sample in atmosphere and calibrate dynamically against a blank crucible, holding repeatability across weeks of unattended runs.

For arbitration results, confirm the slow-ash program can satisfy the ≤500 °C hold requirement of GB/T 212 and match ASTM D7582 tolerances on certified reference materials.

Checklist before you sign

1) CRM verification report on your coal rank; 2) annual heat-capacity or calibration drift data; 3) LIMS/ERP interface documentation; 4) spare-part price list for crucibles, seals and heating elements; 5) warranty terms covering the balance module specifically.