Drying and gas or vapor contact with solids – Process – With nondrying treating of material
Reexamination Certificate
2002-06-28
2004-08-10
Bennett, Henry (Department: 3743)
Drying and gas or vapor contact with solids
Process
With nondrying treating of material
C034S418000, C034S061000, C034S201000, C073S866000, C073S865800
Reexamination Certificate
active
06772536
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the testing and measurement of the resistance to physical breakdown and formation of fine particles of manufactured solid adsorbent materials such as desiccant and catalyst pellets used in industrial dehydration processes.
BACKGROUND OF THE INVENTION
Dehydration processes are used in many industrial applications and are particularly important for liquid and gas hydrocarbon dehydration in the oil and gas industry. Failure of adsorbent and catalyst beds due to physical breakdown of the adsorbent material after repeated regeneration cycles reduces the efficiency and cost effectiveness of the dehydration process in plant operations. Similarly, solid catalyst systems in refining processes can undergo physical breakdown during the process cycle.
This breakdown leads to the formation of fine particles of the solid material or “fines”. The continued accumulation of fines results in an excessive pressure drop across the bed and eventually to the necessity for reduced throughput or premature replacement of adsorbent beds.
The current standard quality control test that measures the strength or hardness of molecular sieves, activated aluminas and catalysts pellets is the crush strength test. This crush strength test, in which a force is applied to the solid pellet (held between 2 plates) until the pellet breaks, is not adequate for assessing the potential of the material to resist breakdown into fines in industrial processes.
To date, manufacturers have not developed a standardized test procedure that measures the “physical stability or resistance to breakdown” of an adsorbent material or catalyst in an industrial process. There is no test procedure that measures the ability of a desiccant to resist breakdown into fines when subjected to successive cycles of hot water or aqueous solutions and steam followed by regeneration or a drying cycle. No organization has provided the industry with a standardized test for evaluating this physical property. There is no test that can identify a material that will fail prematurely in service due to premature physical breakdown.
Some research into the effect of adsorption cycles on the physical properties of adsorbents has been undertaken using a column filled with the adsorbent material to be studied. A gas stream, containing a known amount of moisture, is passed through the column until saturation is achieved and this is followed by a drying cycle. Successive cycled of hydration and regeneration are then performed prior to the removal of the adsorbent for evaluation. The recovered adsorbent can then be evaluated by standard physical tests. Unfortunately such testing is very time-consuming and is unable to provide information on the potential of the adsorbent to break into fines during repeated regeneration cycles. No results from studies relating to the physical breakdown and/or resistance to fines formation after repeated regeneration cycles appear to have been published.
It is therefore one objective of this invention to provide an efficient and reliable method and apparatus for evaluating the physical stability of solid desiccant adsorbents when subjected to successive accelerated cycles of contact with hot aqueous solutions, and steam followed by rapid drying. The method of the invention can also be applied to evaluating the physical stability of other solid materials used as catalysts, e.g., refining catalysts.
An associated principal object is to provide a rating system based upon accelerated aging to reliably predict the relative useful life of solid adsorbents, catalyst supports and like manufactured articles subjected to cyclic wetting and drying processes during their service life.
Another object of the invention is to provide a method and apparatus for the accelerated aging of adsorbents of various shapes and sizes that provides relative physical stability information on the effect of size and shape of the particles in industrial service applications.
A further object of the invention is to provide an accelerated method and apparatus for determining the ability of the solid material to resist breakdown by contact with hot water or water-containing volatile component under conditions similar to those encountered in an industrial application. The test is designed to specifically evaluate the effect of water-soluble volatile components that are adsorbed with the water by the solid adsorbent during the dehydration process. Generally these volatile components, such as organic amines, are detrimental to the physical stability of the adsorbent.
It is also an object of the invention to provide an apparatus and method for improving the quality control that can also be utilized by the manufacturer of solid desiccant materials as an improved standard quality control test for production batches to provide data for grading each batch for purposes that can include warranting useful service life, replacement and maintenance schedules and product pricing.
Another object of the invention is to provide a means for establishing a quality control test for such materials to avoid production of sub-standard batches that would cause premature breakdown and excess fines formation when placed in operational service.
It is yet another object of the invention to provide a method and apparatus that can be used in evaluating the physical stability of solid catalysts, such as refining catalysts, that are subjected to process conditions that result in the eventual physical breakdown of the material. This breakdown reduces the effectiveness of the catalyst and adversely effects the efficient operation of the process.
As used herein, the term “adsorbent material” means any commercially manufactured solid desiccant material that can be used for dehydrating process steams. Examples include molecular sieves, activated aluminas and silicas employed in dehydration applications. These materials come in a variety of shapes, including beads and extrudates, and a variety of sizes (0.5-10 mm). It is also to be understood that “adsorbent material” includes any solid porous material, and particularly those that undergo exposure to heat and steam. This includes various shapes of manufactured articles, such as rings, branched cylinders, and the like which contain a catalyst, or which support a catalyst that are contacted by the process stream.
SUMMARY OF THE INVENTION
In its broadest aspect, the apparatus of the invention comprises a sample treatment chamber for containing a sample in a controlled environment that is isolated from ambient laboratory conditions. The treatment chamber is heated and has an associated cooling system for condensing water vapors withdrawn from the heated chamber. Also communicating with its interior are means for (a) the programmed delivery of a fluid to saturate the sample, which fluid can include water or an aqueous solution, and (b) subjecting the sample to a vacuum to expedite the drying process. After a predetermined number of wetting and dying cycles, the sample is evaluated for physical degradation. The sample material is sieved or screened and any degraded material, or fines, that pass through a sieve or screen of specific pre-determined mesh size is weighed. The ratio of the weight of any fines to the original sample weight is determined, and is preferably and conveniently expressed as a weight percent. A zero percent value for a predetermined number of cycles is optimum and confirms that no fines have been formed during the test protocol and that the material is likely to have a strong resistance to breakdown when subjected to process regeneration cycles.
The apparatus and method of the invention require a relatively small sample of a commercial solid adsorbent material in the form of discrete manufactured beads or extruded material that are subjected to repeated cycles in a laboratory-scale test apparatus under conditions that will lead to the accelerated degradation of the material. The process of the invention includes saturating the sample with water or an aqueous solution containing one or more a
Al-Othman Rashid Mohammad
Ely Timothy Lynn
Mitchell Douglas Patrick
Rahman Abdul
Abelman ,Frayne & Schwab
Bennett Henry
Nguyen Camtu
Saudi Arabian Oil Company
LandOfFree
Accelerated degradation evaluation method and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Accelerated degradation evaluation method and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Accelerated degradation evaluation method and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3339504