|
14/12/2017
|
A:
|
EMMANUELLE MAYOR, PETROVAL, e.mayor@petroval.com
From our experience, the typical density increase when using Densicat technology ranges from 15 to 22 % versus sock loading. Dense loading leads to an enhanced homogeneity of the catalyst packing, with an equal positioning of the catalyst particles which is even highly effective loading spherical catalyst or adsorbents. In spite of a higher packing density, resulting in a slight increase in “initial” pressure drop, the increase of pressure drop during the cycle life is minimized due to a better flow distribution across the catalyst bed (no preferential paths), enhancing performance and cycle time.
In the contrary to the general impression that “dense loading” is a slow process, the additional benefit of the Densicat technology realized by many refineries is an improved loading rate compared to other loading methods. Assuming the facilities to handle the catalyst are adequate, the overall gain in time achieved by the refinery can be as much as 60% (results of loadings performed by Petroval).
|
|
27/09/2009
|
A:
|
Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
Dense loading for various processes enhances the volume of catalyst loaded in the reactor by about 10 to 20 % reducing the bed void fraction in fixed bed reactors. So there are various benefits in terms of thru'put / reactor temperature / catalyst cycle length / extent of reaction or conversion / better flow distribution reducing channeling. Catalyst must have mechanical strength suitable for dense loading otherwise fines will be formed. Loading procedure must be good by experienced loader. Pressure drop may be somewhat more based on reduced void fraction of the bed, but may be controlled within process limits in most of the cases.
Sock loading if not done properly may lead to penalties in terms of enhanced channeling / flow distribution problems consequently higher coking / higher temperatures / lower cycle lengths greater number of regenerations and greater budgets.
|
|
25/09/2009
|
A:
|
keith bowers, B and B Consulting, kebowers47@gmail.com
Dense loading will provide better (more uniform) liquid and gas distribution across the reactor. With 'sock loading', it is VERY difficult to achieve uniform density and pellet orientation both radially and vertically. Actual space velocity will be non-uniform, reducing the ability to precisely control reacting conditions.
This effect is in addition to the lower catalyst volume/weight that can be loaded by the 'sock method.' I do not agree with the concerns about pressure drop build-up with dense loading. If the feed contains particulates, the top bed will plug on the surface unless good 'filter baskets' and inert ball size grading and employed--both of which reduce active catalyst volume.
|
|
24/09/2009
|
A:
|
Randy Alexander, EURECAT, randy.alexander@eurecat.com
Dense loading offers many benefits over sock loading:
Additional Catalyst can be installed in the reactor - up to 15-20% more in the case of extrudates. Maximum catalyst density provides higher reactor activity, longer cycle lengths, and improved bed stability (no settling during the run.
Uniform Void Fraction throughout the bed - eliminates channeling.
Horizontal Orientation of the Catalyst Grains - better contact between reactive phases
Lower Attrition - Good dense loading equipment minimizes attrition vs sock loading.
Dense loading is typically monitored more closely than sock loading, ensuring that the load is installed as carefully as possible.
One of the best dense loading techniques available is the Densicat process from Petroval. Densicat can load 1/20" extrudates at a rate of 30 MT/hr.
The initial pressure drop with a dense loaded bed will be higher than a sock loaded bed. However, the rate of pressure drop increase during the cycle will be lower with a dense loaded bed because little settling will occur. A sock loaded bed will continue to settle during a run since the particles were oriented haphazardly during the loading process.
|
|
24/09/2009
|
A:
|
David Berman, Amlon Resources Group LLC, dberman@amlonresources.com
Dense loading provides greater activity per unit volume than sock loading. However, dense loading may present increased risk of pressure drop as void space between particles decreases. Depending on the application, service, feed, and unit history, careful attention to top-bed grading should be considered for dense loading.
|
|
24/09/2009
|
A:
|
Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
Socks allegedly increase the amount of catalyst one can get into a tubular reactor and help limit the danger of catalyst damage during loading. As a catalyst (tube unloading) contractor we have noticed that whilst tighter catalyst packing may improve plant performance it may also increase the risk of catalyst fusing at the time of discharging spent catalyst. This has resulted in Tubetech developing remote, dry drilling technology to quickly unblock fused reactor tubes, allowing catalyst to be re-used and thus avoid water contamination.
|