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Energy & Fuels · 2024

First pilot-scale demonstration of a pure-ammonia ceramic roller kiln

Pure Ammonia-Fueled Roller Kiln for the Production of Ceramic Tiles: A First Demonstration

Decarbonizing high-temperature industry calls for clean heat sources compatible with continuous production. A pure-ammonia roller-kiln demonstration explores this potential in practical ceramic firing.

The motivation

Ceramic firing requires sustained, stable high-temperature heat. Replacing natural gas with carbon-free ammonia could reduce CO₂ emissions from fuel combustion, but ignition, flame stability, NOx control and product quality must all be addressed. This study moves from burner development to a working pilot kiln to examine the feasibility of pure-ammonia firing.

The approach

Numerical simulations and burner experiments guided a swirl-stabilized, air-staged design. All 32 burners in a 30 m pilot roller kiln were converted to ammonia. The demonstration included a 24-hour normal-production stage, with measurements of staged-combustion, SNCR and SCR performance, ammonia slip, and the appearance and properties of the fired tiles.

The retrofitted pure-ammonia pilot-scale ceramic roller kiln at OCEANO Ceramics, equipped with ammonia supply, burners, flue-gas aftertreatment and emission monitoring. Finished tiles leave at the near end; raw tiles enter at the far end.
The retrofitted pure-ammonia pilot-scale ceramic roller kiln at OCEANO Ceramics, equipped with ammonia supply, burners, flue-gas aftertreatment and emission monitoring. Finished tiles leave at the near end; raw tiles enter at the far end.

Key findings

  1. The 32 ammonia burners supported a 24-hour normal-production stage in the 30 m pilot kiln, with a firing temperature of approximately 1250 °C. This demonstrated the feasibility of pure-ammonia heat supply and tile firing under the tested conditions.
  2. Under the demonstrated conditions, NOx was approximately 170 ppm with staged combustion and fell to approximately 8 ppm with SNCR and SCR. Ammonia slip remained approximately 3–4 ppm. All concentrations were corrected to 18% O₂.
  3. Tiles fired with pure ammonia had a water absorption of 0.01% and a reported strength of 41.6 MPa, meeting the criteria stated in the paper. No obvious color difference from natural-gas-fired samples was visible to the naked eye.
Measured pilot-kiln emissions with staged combustion alone and with staged combustion plus SNCR and SCR. NOx decreases from approximately 170 to 8 ppm; ammonia slip is approximately 3.2 and 3.4 ppm, respectively. All values are corrected to 18% O₂.
Measured pilot-kiln emissions with staged combustion alone and with staged combustion plus SNCR and SCR. NOx decreases from approximately 170 to 8 ppm; ammonia slip is approximately 3.2 and 3.4 ppm, respectively. All values are corrected to 18% O₂.

About this paper

Jiwei Zhou, Zhou Yu, Liuhao Ma, Xuren Zhu, Shiping Jin, Jianguo Du, Xiru Cheng, Shanjun Ke, Guoqing Xie, Yi-Bing Cheng, Yu Wang

Energy & Fuels · 2024 · 38(22) · 22593–22604

Publisher record (DOI)