A Model for the Bulk Crushing Strength of Spherical Catalysts

Li, Yongdan; Wu, Dongfang; Liu, Chang; Shi, Yahua; Wu, Dihua; Fang, Zhiping

doi:10.1021/ie980360j

Cited by 26 publications

(35 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Breakage of the catalyst is of course a balance of the strength of the catalyst on the one hand and the severity of the handling of the catalyst on the other hand. For a comprehensive overview of typical catalyst strength measurements and their importance in applications, we refer to Le Page, 1 Woodcock and Mason, 2 Bertolacini, 3 Wu et al, 4 and Li et al 5 Herein, especially the single pellet crush strength test and the bulk crush strength test are described. The latter is also established as the ASTM7084-04 test.…”

Section: Introductionmentioning

confidence: 99%

Length to diameter ratio of extrudates in catalyst technology I. Modeling catalyst breakage by impulsive forces

2015

View full text Add to dashboard Cite

Natural or forced catalyst extrudate breakage is an important phenomenon during catalyst manufacture. Here, a twoparameter model for predicting the reduction in the length to diameter ratio of catalyst extrudates due to breakage by impulsive forces as experienced in a laboratory drop test is developed. Part II will show how both parameters can be correlated with the strength of the extrudates and the severity of the drop test. For breakage by impulsive forces, the model reveals that extrudates are reduced in length to diameter ratio according to a pseudosecond-order break law. Also, a tie-in exists with the well-known Golden Ratio that is famous for its inherent esthetic value. Applying the model to cases of "severity sequencing" and "severity conditioning" reveals the nonlinear behavior of the length to diameter ratio and yields results that are often nonintuitive and hard to get without this engineering analysis.

show abstract

Section: Introductionmentioning

confidence: 99%

Length to diameter ratio of extrudates in catalyst technology I. Modeling catalyst breakage by impulsive forces

2015

View full text Add to dashboard Cite

show abstract

“…They are related to a wide range of phenomena, ranging from collisional evolution of large asteroids to disintegration of small agglomerates in the processing industries, e.g., pharmaceutical, food, and mining [3,4]. The breakage strength of single particles is a key parameter involved in several powder processing problems, including accidental breakage of the particles during transportation or storage [5], pulverization of catalytic particles [6], comminution efficiency of crushers and mills [7], and yielding transition of the particle beds under bulk compaction [8,9].…”

Section: Introductionmentioning

confidence: 99%

Size effect on the compression breakage strengths of glass particles

Huang

et al. 2014

Powder Technology

View full text Add to dashboard Cite

“…The Weibull moduli for the V, H1, and H2 orientations fall in the range 3.8‐5.8. These are consistent with reported values for single pellet crush strength for various pellet geometries in the literature, 1.8‐6.5 . While the moduli for the D1 and D2 orientations fall in the range 5.2‐9.3, and correspond to lower scatter in the failure loads.…”

Section: Resultsmentioning

confidence: 99%

“…Porosity design is important for scaffold materials with macropores of >50 nm dominating mass transport . The porosity measurement here will not resolve down to this level, but our measured porosity is consistent with values for alumina pellets in the literature …”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Failure of commercial extruded catalysts in simple compression and bulk thermal cycling

Young

Henderson

Buchanan

et al. 2017

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

The mechanical performance of three commercial extruded catalyst pellets was characterized by single particle compression testing in five orientations and bulk crush testing during thermal cycles from 20°C to 900°C in a reformer tube. Failure loads were analyzed with Weibull statistics, and fragment shapes were cataloged. Maximum principal stresses from finite element simulations were consistent with the shapes of fragments from single pellet tests. In smaller scale bulk tests, excluding pellets in contact with the top and bottom plates, the most common location of damaged pellets was in contact with the reformer wall. In one large-scale test (280 pellets), damage was most common in pellets at the reformer wall. The most common fragment shapes from ex-service single pellet tests and bulk tests are similar, but differ from those from single pellet tests. Neither single pellet compression testing nor conventional bulk crush testing is a sufficient analog for the loading conditions on catalyst pellets in reformer tubes. This study demonstrates that catalyst pellet damage occurs in each full thermal cycle, and that using thermal cycling to reproduce the boundary conditions in service is essential for future studies. K E Y W O R D Scatalysts/catalysis, finite element analysis, fracture, thermal treatment | INTRODUCTIONCatalyst pellets are used in gas phase reactions including methane steam reforming where the conversion takes place inside a reformer furnace operating at around 900°C by passing methane and steam through hundreds tubes filled with the pellets. The operating temperature of the reformers is limited at the high end by the decreasing creep life of the alloy reformer tubes and at the low end by the decreasing efficiency of the desired reaction. The temperature of reformers is monitored as part of process control and is observed to fluctuate during operation. All temperature cycles induce thermal expansion on heating and contraction on cooling in the steel reformers. When the plant shuts down, there is a complete temperature cycle. It is anticipated that catalyst slumping on heating and crushing on cooling will damage catalyst pellets and adversely affect the reforming process.Pellets are designed for optimum heat transfer, gas flow, catalytic efficiency, and stability.1 There is a large literature on alumina scaffolds including some studies of mechanical performance, 2-4 but less on calcium aluminate. 5-8 Catalyst pellet damage and fracture affects the pressure drop, local temperature, and overall efficiency of the reforming process. 9 Understanding the relation of temperature cycles to pellet damage is important for plant operators in order to prioritize control of processing variables. Robustness of pellets is assessed through single particle strength (SPS) or side crushing strength (SCS) where a pellet is loaded in compression between two platens, multiple particle crushing strength (MPCS) where a spherical pellet is loaded in compression between a platen and a jig with

show abstract

A Model for the Bulk Crushing Strength of Spherical Catalysts

Cited by 26 publications

References 21 publications

Length to diameter ratio of extrudates in catalyst technology I. Modeling catalyst breakage by impulsive forces

Length to diameter ratio of extrudates in catalyst technology I. Modeling catalyst breakage by impulsive forces

Size effect on the compression breakage strengths of glass particles

Failure of commercial extruded catalysts in simple compression and bulk thermal cycling

Contact Info

Product

Resources

About