Mole ratio of H2 to Cl2 in 2-in-1 graphite synthesis of HCl
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This post was last edited by sunjl1981 on 2013-1-6 23:56. Regarding the molar ratio of H2 to Cl2 used in the synthesis of HCl from graphite in a 2-in-1 process, the ratios mentioned are 1:1.05 and 1:1.15–1.20. What is the appropriate ratio in actual production? Q # , , &
Generally, the ratio is Cl2:H2 = 1:1.05–1.10. In production, the purity of HCl is the key factor, with no free chlorine allowed in the HCl. In production, the decision can be based on the analysis results of the purity of hydrogen, chlorine, and hydrogen chloride; there is no fixed value. Additionally, the ratio can be determined by the color of the flame, with it being best to keep the flame blue-white or light yellow-green in color.
It seems the ratio you’re asking about should be 1:1.05–1.1 for chlorine to hydrogen, not hydrogen to chlorine.
1. In the hydrogen chloride synthesis process, an excess of hydrogen is used to ensure complete reaction of chlorine; the water pump does not come into contact with chlorine, thereby protecting the atmospheric environment； 2. During the production process, the risk of excessive hydrogen being converted into excessive chlorine is lower than that of the reverse process ； 3. During the production process, a hydrogen chloride purity of 88–92% is appropriate; too low a purity results in waste of hydrogen, while too high a purity poses safety risks ； 4. The color of the flame is more noticeable in iron furnaces, while it is less apparent in quartz lamp holders ； 5. The purity control determines the ratio of chlorine to hydrogen. :lol
The ratio of H2 to Cl2 should be maintained at 1.05:1. Last edited by limingshuguang on 2007-12-10 13:12.]
How to measure and monitor it?:handshake
Generally, the ratio of Cl2 to H2 is 1:1.05–1.10, and this ratio can be controlled using flow meters. It can also be reflected in the flame of the synthesis furnace: a dark red flame indicates an excess of H2, while a yellow-green flame indicates an excess of Cl2. A normal flame is bright blue-white in color. Sometimes, variations in the temperature and purity of the raw materials result in different flame colors, which can be determined based on experience.
Automatic control can also be achieved by installing a flow meter, but during the control process, discrepancies may arise between the displayed flow rate and the actual flow rate due to changes in furnace pressure; therefore, appropriate calibration of the instrument is necessary
I think the ultimate indicator is still the purity of hydrogen chloride. 88-92% is the ultimate control measure. Right? :lol
The HCl used to produce trichlorosilane has a purity of 92% or higher
Our control level seems to be a bit higher than what you mentioned~ However, our flame is cyan-white, and this aspect is well controlled; a white color indicates excess hydrogen, while a yellow or slightly red color suggests excess chlorine. Last edited by limingshuguang on 2007-12-13 14:43]
Our factory maintains a ratio of Cl2:H2 at 1:1.05–1.10. In production, the ratio is determined primarily by the color of the flame; it is best to keep the flame in a bluish-white or light yellow-green color. This is mainly controlled through long-term experience. Another indicator is the purity of HCl, which is determined based on specific requirements. We generally keep the concentration of hydrogen chloride gas between 85% and 90%, which requires a high purity of both hydrogen and chlorine; otherwise, it is not possible to achieve this concentration ；
The ratio of chlorine to hydrogen is 1:1.05–1.1. In practice, the mixing ratio is determined based on the color of the flame, with the ideal being a bluish-white flame. An excess of hydrogen is used during production to ensure that all the chlorine reacts, thereby preventing chlorine from being present in the exhaust gases and protecting the environment; it also helps to reduce the amount of free chlorine in hydrochloric acid. Since there may be variations in the mixing ratio due to issues with the measuring instruments, it is necessary to constantly monitor the color of the flame and adjust the amounts of hydrogen and chlorine accordingly.