A series of laboratory researches were carried out to investigate the influence of different factors to the reaction between NaNO2 and NH4Cl which were often used in oilfield for energization and blockage removal. The experiments were carried out under atmospheric pressure and high pressure respectively to evaluate the capacity of producing N2.The experimental groups with higher reactants concentration, higher hydrogen ion concentration and higher temperature showed the larger gas production, while the higher pressure has little impact on gas production. The heat generation performance and peak temperature of the reaction went up with the increase of the reactant concentration, the hydrogen ion concentration and the initial reaction temperature. The addition of hydrogen ion can promote the reaction rate, but the side reactions that generated NO/NO2 (reddish brown gas) would happen when the hydrogen ion concentration exceeds 0.0356 mol/L. When the molar ratio of sodium nitrite to ammonium chloride is 1:1(compared with other ratio such as 1:1.5,1:2 and so on ), the mixed system has the best gas production capacity. The gas generating efficiency of the mixed system reached a plateau at approximately 56% within 4h when the reactant concentration surpassed 1.5 mol/L. The kinetic equation of the reaction between NaNO2 and NH4Cl based on the experiments is dC/dt = -7.103x107CH+1.3291C02.0949e(-51.28kJ/RT),which agreed with the experimental data. The intermediates present in the reaction are H2N-NO and HN=NOH ,the SN2 reaction between the nucleophile NH3 and the electrophile N2O3 to form H2N-NO in the rate-limiting step determines reaction rate, and the H2N-NO can rapidly form HN=NOH that can spontaneously decompose to form the final products N2 and H2O.

Study on the characteristic of reaction between sodium nitrite and ammonium chloride

2019 Fall National Meeting

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