Zhonghe Case | Lithium Salt Project-Zhonghe

Conversion Rate from 89% to 90.56%: A Case Study of Multi-Fuel Rotary Kiln Burner Commissioning

30 October 2026

Zhonghe Case | Lithium Salt Project

Project Background

A lithium salt company operates a 4×60m rotary kiln with a design capacity of 900 t/d, using natural gas, water gas, and biomass. During commissioning, output stabilized at 33 t/h, but the assay conversion rate was only ~89%, below the 90% third-party requirement. Systematic commissioning was needed to improve clinker qualification. Main equipment and process parameters are shown below.

Parameter	Value
Kiln specification	4×60m
Design output	900 t/d
Natural gas	Calorific value 8100 kcal/kg
Water gas	Calorific value ~1500 kcal/Nm³, supply pressure 30–35 kPa
Biomass	Calorific value 3300–3800 kcal/kg; fineness: 60 mesh pass rate 60%, 40 mesh pass rate 100%
Clean-air fan	Flow 160 Nm³/min, 19.6 kPa
Pulverized-coal fan	36.8 m³/min, 44.1 kPa, 45 kW
On-site output	33 t/h (stable during commissioning)

Core Problems

Kiln 1: Natural gas only—flame too strong/short, concentrated combustion, uneven kiln temperature, prone to local overheating and quality fluctuation.
Kiln 2: Water gas + biomass—short flame, front ring, limited adjustment space, hard to improve by conventional means.
Common issues: Biomass use lowered kiln temperature—suspected excess air, unstable feed, no metering; inaccurate central control temperature misled adjustments; natural gas tripped—suspected low gas volume or flame detector failure, requiring interlock bypass to resume production.

Commissioning Approach

Goal: stable kiln conditions and qualified assay (conversion rate 90%). Stepwise adjustment: first improve flame shape via air valves and primary air frequency; then fix kiln speed and primary air volume to verify fuel ratio; adjust burner axial/swirl compensators as needed to boost combustion efficiency. All decisions based on assay data, forming a closed loop of "adjust—sample—assay—readjust."

Commissioning Process and Measures

The 5-day commissioning followed a stepwise approach: flame first, then fuel ratio, then stable conditions. By adjusting axial/swirl compensators and central air valves, lowering primary air frequency, and discontinuing biomass, kiln temperature and atmosphere improved—conversion jumped from 77% to 91.05%. Later, water gas was gradually increased and natural gas reduced, with no further burner adjustment; conversion stabilized at 90–92%, and the final third-party assay was 90.56%, qualified.

Commissioning Results

Quality target met: Conversion rate rose from ~89% to above 90% and remained stable; third-party assay 90.56%, qualified.
Burner and fuel validation successful: Burner flame was fine; all three fuels can be used simultaneously. Low conversion was mainly due to improper system air usage. Considering stability, water gas + natural gas co-combustion was finalized.
Stable kiln conditions: Output steady at 33 t/h; kiln temperature and atmosphere improved.

The 5-day commissioning raised conversion from 89% to 90.56%, stably meeting the standard—validating Zhonghe's burner adaptability and our after-sales team's multi-fuel commissioning capability. Guided by assay data and kiln stability, we deliver not just combustion equipment but full-process technical support, safeguarding your production end to end.