Can the pre-fluidizing steam in the pre-lift section of the lift pipe be replaced with dry gas?
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Our unit is a 600,000 tons per year coaxial FCC unit. During the initial startup phase, steam is used as the pre-lift medium in the reaction lift column; once normal operation is achieved, steam is replaced by dry gas coming from the top of the stabilizer reabsorber as the pre-lift medium. The pre-fluidization steam used in the lift column remains at 1.0 MPA both during the initial startup phase and after normal operation has been established. Is it possible to use dry gas as the pre-fluidization medium in this case? :)
As long as the objectives of pre-heating and pre-sulfurization are met, either steam or dry gas can be used; in the case of steam, attention must be paid to catalyst thermal degradation and the removal of water from the products in the fractionation tower； For dry gas, it is necessary to consider whether the compressor suitable for rich gas can meet the requirements
Agree with the view above; one also needs to pay attention to the issue of protecting oneself while cutting materials.
It’s completely possible, but it’s necessary to ensure that the dry gas does not contain any liquid.
Since you’ve raised this point, buddy, please explain what the advantages are of making such a change What possible side effects could arise? What benefits can be achieved in terms of energy savings and efficiency improvement through accounting? Everyone can also be eager to learn* and use it as a reference. Thank you! :P
Using dry gas as a substitute for pre-heating steam is no longer anything unusual; there are also many topics on forums that discuss this topic, so the original poster can give it a search!
It is a fact that the pre-lift medium has been changed from steam to dry gas. What the original poster is referring to is the change of the fluidizing medium at the bottom of the pre-lift section from steam to dry gas; here we still use steam. Personally, I think it would be good if this change were made, but after stopping the feed, be sure to go to the site to close the manual valve
The fluidized steam at the bottom of the pre-raising column is replaced with dry gas; it is essential to close the dry gas manual valve on-site when feeding to the unit is stopped.
It can be argued – what is the amount of steam used for fluidization? Great idea
We use both dry gas and steam together; generally, we try to use as much dry gas as possible. The dry gas should contain as few components with carbon numbers above 3 as possible, as it helps to deactivate heavy metals on the catalyst. Excessive steam can cause the catalyst to become inactive, and there is also an increase in sulfur-containing wastewater. We use a little over 10,000 cubic meters of dry gas and just over 1 ton of steam. The adjustments are mainly made based on the catalyst density in the pre-raising section and the pressure drop in the rising pipe, that is, depending on the reaction time