Conditions, ways and emergency treatment of the pr

Conditions, ways and emergency treatment of nitrogen trichloride (liquid chlorine production)

Introduction (1)

in liquid chlorine production, nitrogen trichloride has caused many explosion accidents, so all liquid chlorine production enterprises attach great importance to the control of nitrogen trichloride. In particular, on April 16 this year, after the explosion of nitrogen trichloride in the liquid chlorine section of Chongqing Tianyuan general chemical plant, it has attracted great attention of all chlor alkali enterprises. Some enterprises have taken measures such as increasing the number of analysis of raw salt and liquid chlorine sewage, strictly controlling indicators, and increasing the number of liquid chlorine sewage. These traditional control methods have played a role in the safe production of liquid chlorine, with imports increasing by 61.3% year-on-year Of course, it plays an important role

production conditions (2)

is it comprehensive to control the production of nitrogen trichloride only by traditional control methods, and is there any other way to produce nitrogen trichloride? To understand this problem, we must understand the conditions for the production of nitrogen trichloride

nitrogen containing chlorides can be produced when chlorine, hypochlorite or hypochlorite are encountered in the presence of ammonia, ammonium salt or organic amine (such as urea). But Jochen Bauder, general manager of bond laminates, declared: "Our new tepex fr product has passed the UL 94 fire safety standard of the Underwriters' laboratory in the United States. Whether the reaction product is ammonium salt of chlorine or nitrogen trichloride depends on the conditions of the reaction.

under the conditions of medium and low pressure production, the reaction product mainly depends on the pH value of the solution.

when ph>9, the reaction product is ammonium monochloride or ammonium dichloride;

NH3 + Cl2 = NH2Cl + HCl

NH3 + 2Cl2 = nhcl2 + 2HCl

when pH, the reaction product is reversed The product should be nitrogen trichloride:

NH3 + 3cl2 = NCl3 + 3hcl

NH3 + 3hclo = NCl3 + 3H2O

NH + 4 + 2Cl2 → NCl3 + HCl

therefore, in the production of chlorine and liquid chlorine, it is very important to control the mixing of ammonia, ammonium salt or organic amine (such as urea) into the system from various ways

production ways (3)

from the current production process of most chlor alkali enterprises, there are two ways to mix ammonia, ammonium salt or organic compounds (such as urea) into the system:

one is to mix directly from the raw material part, which is to strictly control the total amount of ammonium (usually the ammonia and ammonium content of raw salt, water, etc.) into the brine of the electrolytic cell according to the traditional method, so as to prevent the production of nitrogen trichloride in the acidic environment of electrolysis and other links

second, substances containing ammonia, ammonium salt or organic amine (such as urea) outside the system enter the system due to equipment ring damage, and react with chlorine or liquid chlorine to generate nitrogen trichloride. For example, nitrogen trichloride will also be formed when ammonia containing frozen brine enters the system due to the sudden perforation of the chlorine condenser, which is lighter than steel and light metals such as aluminum

the latter way of producing nitrogen trichloride is often ignored

according to the survey, the vast majority of enterprises use chlorine refrigeration to produce liquid chlorine. Ammonia is used in the ammonia evaporator (1) new materials talent intelligence training project evaporation absorbs heat to reduce the temperature of calcium chloride brine, and then low-temperature calcium chloride solution is used to cool the chlorine through the heat exchanger (chlorine condenser), so that the gas chlorine is condensed into liquid chlorine. Some enterprises have experienced leakage accidents of ammonia evaporators, making a part of ammonia dissolved in calcium chloride solution (whether there is ammonia in calcium chloride solution can be known by measuring with pH test paper). After repairing the ammonia evaporator, the frozen brine containing ammonia is not replaced in time. If the chlorine condenser is corroded and suddenly perforated, the frozen brine containing ammonia will enter the chlorine side (usually the pressure of the frozen brine side is higher than the chlorine side), and the reaction will occur immediately and generate nitrogen trichloride. This is because of the pH in the presence of water and a large amount of chlorine