Abstract: To avoid the energy waste in the production of furnace grade phosphoric acid, a new phosphoric acid tower with circular water wall was designed, which could recover waste heat to produce superheated steam.A three dimensional mathematical model of phosphorus combustion in the new phosphoric acid tower was developed by incorporating the k-ε turbulence model, eddy dissipation turbulent combustion model and P-1 radiation heat transfer model.The streamline field distribution, temperature distribution and species concentration distribution were predicted by numerical simulation.The results showed that phosphorus combustion mainly took place in the injection zone of atomized phosphorus,and the maximum combustion temperature and exit temperature were 1790 K and 970 K respectively which conformed well to practical data.