Catalytic Air Pollution Control

Heck, Ronald M.; Farrauto, Robert J.; Gulati, Suresh T.

doi:10.1002/9781118397749

Cited by 358 publications

(324 citation statements)

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“…The cell was equipped with two Dekati Mass Monitors (DMMs) that measured PM on a mass basis. A correlation was found previously at Ford for PM and PN during extensive GDI vehicle testing [2], where 2 × 10 12 / km PN is approximately equal to 1 mg/km PM.…”

Section: Methodssupporting

confidence: 73%

Gasoline Particle Filter Development

Lambert

Chanko

Dobson

et al. 2017

Emiss. Control Sci. Technol.

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Gasoline particle filter (GPF) development includes optimization of multiple, competing targets: low backpressure, high clean filtration, acceptable strength, high oxygen storage capacity, small size, and low cost. A three-way catalyst + GPF system needs to meet targets for hydrocarbons, carbon monoxide, and nitrogen oxides in addition to particle mass and/or particle number. GPFs behave differently than diesel particle filters (DPFs) in terms of regeneration and ash loading behavior due to vastly different operating conditions. In a relatively clean exhaust condition on GDI relative to diesel, an empty GPF can have filtration efficiencies on the order of 60%. This was improved to 80-90% with a small amount of soot and/or ash on the filter walls, or higher catalyst washcoat loading. In the course of this work, models were developed to predict backpressure, filtration, and chemical performance.

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Section: Methodssupporting

confidence: 73%

Gasoline Particle Filter Development

Lambert

Chanko

Dobson

et al. 2017

Emiss. Control Sci. Technol.

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“…NOx is generated primary by the combustion of fossil fuels, both in transportation and industrial processes. However, transports, and especially those working with diesel engines, are the main sources of NO x emissions [2]. Selective catalytic reduction (SCR) of NOx by ammonia has become the most used emission control [3], and catalysts based on vanadia are in commercial use since 2005 for diesel vehicles [4].…”

Section: -Introductionmentioning

confidence: 99%

Rational direct synthesis methodology of very active and hydrothermally stable Cu-SAPO-34 molecular sieves for the SCR of NOx

Martínez-Franco

Moliner

Franch

et al. 2012

Applied Catalysis B: Environmental

159

103

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A one-pot direct synthesis of Cu-SAPO-34 has been achieved that allows more than 90% yield in the material synthesis. By this method it is easy to control the Cu-loading in the Cu-SAPO-34. It is presented that a maximum in hydrothermal stability with very high activity for NOx SCR with NH 3 is obtained for an optimum Cu loading. KeywordsOne-pot synthesis, silicoaluminophosphate, SAPO-34, selective catalytic reduction (SCR), nitrogen oxides (NOx) Highlights-Rational direct synthesis of Cu-SAPO-34 by using the co-directing templates.-Easy control of Cu-loading in Cu-SAPO-34 materials, and very high solid yields.-High activity and stability for SCR of NOx. In fact, the SCR of NOx experiment described by Xiao was performed on the sample with Si/Al ratio of 4.1 under mild conditions (low space velocity), and the stability of the synthesized samples under hydrothermal treatments was not studied. In addition to SSZ-13, the chabazite molecular sieve can be synthesized as silicoaluminophosphate form, . Cu-exchanged SAPO-34 has also been shown as a very stable and active material for SCR of NOx [14]. In the last years, some groups have attempted the direct preparation of Cu-SAPO-34 in order to achieve an inexpensive and more efficient synthetic route for this metal-substituted material [15].In those cases morfoline and copper oxide were used as organic structure directing with the tetraethylenepentamine (TEPA, 99%wt, Aldrich). This mixture was stirred for 2 hours until complete dissolution. Secondly, distilled water and phosphoric acid (85% wt, Aldrich) were added and stirred during 5 minutes. Third, alumina (75%wt, Condea) 7 and silica (Ludox AS40 40%wt, Aldrich) sources were introduced in the gel mixture.Finally, diethylamine (DEA, 99%wt, Aldrich) and SAPO-34 seeds (5%wt of expected final yield), if required, were added in the gel, and the mixture was stirred during 30 minutes. The resulting gel was transferred to an autoclave with a Teflon liner, and heated at 150ºC under static conditions during the required time (see experimental conditions for each sample in Table 1, Table 3, or Table 4). Crystalline products were filtered and washed with abundant water, and dried at 100ºC overnight. The samples were calcined at 550ºC in air to properly remove the occluded organic species. washed with distilled water, and dried at 100ºC overnight. The sample was calcined at 550ºC in air to remove the occluded organic species.In order to perform the Cu ion exchange on this SAPO-34 material, the calcined sample was first washed with NaNO 3 (0.04M), and afterwards, the sample was exchanged at room temperature with a Cu(CH 3 CO 2 ) 2 solution (solid/liquid ratio of 10g/L). Finally, the sample was filtered and washed with distilled water, and calcined at 550ºC for 4 h. 2.2.-CharacterizationX-ray diffraction (XRD) measurements were performed on a multisample Philips X'Pert diffractometer equipped with a graphite monochromator, operating at 40 kV and 45 mA, and usig Cu K α radiation (λ = 0,1542 nm).The chemical analyses were car...

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“…(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) can principally be used in the numerical simulation of laminar as well as turbulent flow fields; the so-called Direct Numerical Simulations, DNS. In practice, however, the solution of the Navier-Stokes equations for turbulent flows demands a prohibitive amount of computational time due to the huge number of grid points needed to resolve the small scales of turbulence.…”

Section: Modeling Of the Interactions 275mentioning

confidence: 99%

“…Catalytic monoliths can serve as an example. They are frequently used for the reduction of pollutant emissions from automobiles [1], selective oxidation [2][3][4] and reforming of hydrocarbons [5,6], and combustion of natural gas [7][8][9]. Figure 1 illustrates the physics and chemistry in a catalytic combustion monolith that glows at a temperature of about 1,300 K due to the exothermic oxidation reactions.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Deutschmann

2014

Catal Lett

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The catalytic surface interacts with the gasphase by a variety of chemical and physical processes. Hence, optimization of design and operation conditions of catalytic reactors do not only require the understanding of the catalytic reaction sequence but also its coupling with mass and heat transport and potential homogeneous reactions. The chemical, thermal, and mass-transport interactions between the catalytic surface and the gas-phase are discussed in terms of the individual and combined interactions. The state-of-the-art modelling of reactive flows and its coupling with the catalytic surface is summarized. The interactions are illustrated by a number of examples such as reforming of hydrocarbons, catalytic combustion, exhaust-gas after-treatment, each focusing on a special aspect of catalyst-gas interactions. The potentials and limitations of the numerical simulations will be discussed including experimental techniques for model validation.

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Catalytic Air Pollution Control

Cited by 358 publications

References 0 publications

Gasoline Particle Filter Development

Gasoline Particle Filter Development

Rational direct synthesis methodology of very active and hydrothermally stable Cu-SAPO-34 molecular sieves for the SCR of NOx

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

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