Investigating the stability of flame front and the composition of combustion products of ammonia in oxygen in the presence of hydrogen fluoride

Abstract

Ammonium bifluoride is a by-product of a number of industrial processes, which has not sufficient marketing in the industry. Thus, it should be created a method for producing hydrogen fluoride, the major fluorinating agent in the modern industry, from ammonium bifluoride. The authors propose a way for producing hydrogen fluoride by processing ammonium bifluoride in oxygen. Adiabatic temperature of the products is about 2400 K. In this paper, using the calculations performed via thermodynamic program complex ASTRA.4, it was shown that at a following ratio of chemical elements N-5H-2F-1,5O appropriating to the proposed process, in the equilibrium mixture in the temperature range 600-2500 K, hydrogen fluoride is the only fluorine-containing substance. Nitrogen fluorides and hydroxy nitrogen fluorides are absent. Combustion of ammonia in oxygen had been extensively studied. However, there is have not been uncovered any data about this process in literature. The authors have experimentally investigated the combustion process of ammonia and oxygen in the presence of hydrogen fluoride. It have been showed that, for the tunnel burner reactor type used in the experiments, at a molar ratio of ammonia to hydrogen fluoride flow rates 1:2, it is possible to form a stable flame in oxygen, supplied by stochiometry, only by utilizing methane as fuel. The conditions were determined for the ratio of the components consumption, when, in the combustion mode, the conversion of ammonia, when methane was fed into the reaction zone, reached 98 % in a laboratory installation, and hydrogen fluoride remained stable.

Keywords

• ammonium bifluoride
• ammonia
• hydrogen fluoride
• combustion
• tunnel burner reactor