How to reduce nitric trichloride in the system
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This post was last edited by sunjl1981 on 2013-1-6 at 21:39. Analysis of the reasons for the excessive nitrogen trichloride levels: Total ammonia levels in various samples – 07.10.31: Industrial water, 5.01 PPm; 07.11.1: Sewage, 8.5 PPm; 07.11.28: Nanfang Power Station, 2.4 PPm; 01.11.28: Yingzui Power Station, 6.8 PPm; 07.10.24: Haiyan, 3.5 PPm. 1. Analysts often take samples long after vaporization occurs, which tends to result in higher analysis values. 2. During the period from 11-24 to 12-24, the cold weather, combined with a high concentration of alkali, caused the discharge pipes inserted into the alkaline solution to become clogged due to salt crystallization ； Nitrogen trichloride could not be removed, resulting in a sharp increase in its concentration during that period. 3. Industrial water itself has a high level of total ammonia. After clearing the discharge pipe, the nitrogen trichloride level was generally below 10 PPm, which indicates that a blockage in the discharge pipe was the main cause of the increase in nitrogen trichloride levels. This is something that happened to us some time ago. Let’s discuss everyone’s ideas on how to minimize the levels of nitrogen trichloride in the system. 1. Will it decompose partially after passing through the turbine? 2. Is it necessary to disassemble and clean the liquid chlorine pipes? #，， &
Such a great post, and no one has given it a rating: Q This post was last edited by limingshuguang on 2008-1-14 at 13:05
During the compression process in the turbine, due to the high temperature, most of the nitrogen trichloride can decompose. There is no need to clean liquid chlorine pipelines unless they are blocked. I welcome your personal opinions
It is not necessary to clean the liquid chlorine pipelines; what is important is to drain waste regularly. The explosion limit for liquid chlorine is 18%, while that for gaseous chlorine is 6%. As long as these limits are not exceeded, there will be no problems.
I believe the key is to address the issue at its source, that is, to remove ammonium from brine during the preparation of primary brine – this is the main measure to ensure a reduction in the nitrogen trichloride content in the system. More specifically, it is necessary to start by controlling the amount of ammonium present in the fresh water and raw salt used for salt production.
Add an oxidant to the saline solution to remove ammonia, or regularly discharge nitrogen trichloride in the liquid chlorine process.
Given the current total ammonia level of the poster, and with the addition of the submersed packaging process, there is basically no need to worry about the accumulation of nitrogen trichloride
This post was last edited by 181128425 on 2009-6-21 at 13:41. Nitrogen trichloride (NCl3): 1. Properties: A yellow, viscous liquid or rhombic crystals; it has an odor similar to that of chlorine. It volatilizes easily in air; at concentrations of 5–6%, it poses a potential explosion risk. At 60 degrees Celsius, it can decompose and explode under the influence of vibration or ultrasonic waves. It will explode immediately if exposed to direct sunlight or magnesium light. (The explosion temperature is 2128 degrees.) Its boiling point is less than or equal to 71 degrees, its melting point is less than or equal to minus 40 degrees, and its auto-ignition explosion temperature is 95 degrees. 2 Formation of nitrogen trichloride: A small amount of ammonia ions are present in electrolyzed salt water; at the anode of the electrolytic cell (with a pH of 2–4), these react with chlorine to produce NCl3. 3 Preventive measures: a Reduce the ammonia content in the water used for desalination. b It is strictly prohibited to use steam to heat containers for liquid chlorine, such as cylinders and preheaters. c. Control the packaging pressure to ensure it does not exceed 1.10 MPa. d. There should be a reserve amount of liquid chlorine left in the steel cylinders or other containers used to store chlorine; complete evaporation of this liquid chlorine is strictly prohibited. (Leave a residual amount of 0.5–1.0%) If the content in the effluent exceeds 80 g/l, the frequency of effluent discharge should be increased; if it exceeds 100 g/l, feeding must be stopped. 4 Methods for removing NCl3: a. Decomposition using Monel alloy. b is washed with hydrochloric acid. In the drying process, the high-temperature chlorine gas supplied from electrolysis is washed with saturated chlorine water. To prevent explosions caused by the accumulation of nitrogen trichloride in chlorine gas, the following measures are taken: a) The drainage systems of equipment such as liquid chlorine vaporizers and heat exchangers should be used for regular drainage, with each piece of equipment being drained once per week. b The deactivated heat exchanger must not allow raw chlorine gas to enter or exit. When discharging waste, a certain amount of liquid chlorine must be released; it is not allowed to discharge only gaseous chlorine ； The discharged liquid is absorbed with an alkaline solution. d Strengthen analytical monitoring and adhere to daily analysis.
In summary, there are four points: 1. Reduce the generation of nitrogen trichloride at the source by controlling the ammonium content in raw salt； 2. During the first purification step of brine, add an appropriate amount of oxidant to remove ammonium from the salt ； 3. For safety reasons, liquid chlorine should be discharged regularly ； 4. Based on the analysis results, understand the actual situation regarding the generation of nitric trichloride in one’s own company, and have a clear idea of its concentration within the system. It is essential to carry out regular testing and analysis to ensure accurate guidance for production processes.