Weekly Question: What are the effects of excessively high or low outlet CO levels on subsequent processes?
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This post was last edited by 654262293 on 2011-1-2 23:17. What impact does an excessively high or low transformation outlet CO have on subsequent processes? Depending on the different processes used in subsequent steps, they can be described separately! (January 2, 2011)
The last edit to this post was made by 654262293 on 2011-1-7 at 09:02. For subsequent purification processes such as copper washing, methanation, and liquid nitrogen washing, it is of course better to have as low a CO level at the exit of the conversion process as possible. This requires efforts to reduce the CO content at that exit under economic operational conditions. However, for the purification processes related to the production of methanol as a by-product, the CO content at the exit of the conversion process cannot be too low; it seems to need to be kept between 3–5%. I haven’t dealt with this before, so I’m not entirely sure, and the CO content also needs to be adjusted according to the amount of alcohol produced
The last edit to this post was made by 654262293 on 2011-1-7 at 09:02. Too high a CO level increases the load on the subsequent dimethyl unit, which in turn can lead to catalyst poisoning in the synthesis unit. Too low a CO level reduces the reaction heat in the dimethyl unit, increasing electricity consumption
This post was last edited by 654262293 on 2011-1-7 09:02. A value that’s too low has little impact; it should be considered a good thing… But if the value is too high, it’s definitely not good – at least the oxygen content can poison the catalyst……
This post was last edited by 654262293 on 2011-1-7 09:03. For synthetic ammonia, too high a CO concentration increases the burden on subsequent methanation (or liquid nitrogen washing). For the methanol process, the impact is somewhat smaller.
This post was last edited by 654262293 on 2011-1-7 09:04. 1. If the carbon monoxide level is too low, it will affect the methanol production. 2. If the carbon monoxide level is too low, the hydrogen-to-nitrogen ratio will fluctuate. 3. If the carbon monoxide level is too low, different refining processes have varying impacts.
The last edit to this post was made by 654262293 on 2011-1-7 at 09:04. For the ammonia synthesis process, regardless of the refining techniques used in subsequent stages, it is better to have a lower CO content at the outlet of the shift reactor. Firstly, this allows for the conversion of CO into H2, which is an effective gas for ammonia production; secondly, it reduces the workload on the refining units. In the diol process, the alcohol-to-ammonia ratio can be adjusted by changing the level of CO in the outlet; in the monoalcohol process, this ratio is generally kept around 20%. When the activity of the methanol catalyst is high at the beginning, the ratio can be kept slightly lower, while it can be increased slightly as the catalyst ages.
The last edit to this post was made by 654262293 on 2011-1-7 at 09:05. 1. If methanol is being produced, too high or too low levels of CO can affect the purification process; this leads to an imbalance in the hydrogen-to-carbon ratio during methanol synthesis, resulting in a reduced synthesis rate and lower output； However, the CO content in the recycle gas is high, and the purity of the crude alcohol product is high ； 2. If used for the production of synthetic ammonia, too high a CO level increases the load on the liquid nitrogen cooling unit; minor excesses at the outlet can lead to catalyst poisoning and deactivation ； The CO level is too low, which results in high consumption of conversion steam, accelerated catalyst degradation, and a shortened service life – making it uneconomical ；
This post was last edited by 654262293 on 2011-1-7 09:05, followed by two washing processes: Excessively high levels increase the load on liquid nitrogen washing, but this has no impact on ammonia synthesis. Too low: The liquid nitrogen washing may result in insufficient cooling capacity, requiring additional cooling; this has no impact on ammonia synthesis. In the purification process using potassium carbonate: Too high: An increased amount of inert gas in the synthesis circuit is not conducive to the progress of the synthesis reaction. Too low: It should have no impact
The last edit to this post was made by 654262293 on 2011-1-7 at 09:06. The issues in the subsequent processing stage related to alcoholization are as follows: 1. Excessively high levels of carbon monoxide can overwhelm the alcoholization catalyst, leading to catalyst poisoning in the synthesis tower; moreover, excessively high temperatures during alcoholization can also cause problems. 2. Excessively low levels of carbon monoxide force the use of electric heaters for heating during the alcoholization process
This post was last edited by 654262293 on 2011-1-7 09:06. Simply put, a too-low value is good for the backend system! The lower, the better. If it’s too high, it increases the amount of inert gas in the system, resulting in a decrease in output