Experimental Study on the Influence of DPF Micropore Structure and Particle Property on Its Filtration Process

Abstract

A single layer filtration system was developed to investigate the filtration and regeneration performance of diesel particle filter (DPF). The particle layer thickness was directly measured online to analyze the different filtration stages. The influence of particle property on particle layer stage performance was also investigated. The results indicate that the filtration velocity can greatly affect the deep bed filtration stage, and the deposited particle layer can be compressed even in very low filtration velocity and higher filtration velocity trends to form denser particle layer. Optimizing the pore structure can effectively shorten the deep bed filtration stage and reduce the pressure drop eventually. An empirical function was proposed to relate the pore structure and the initial increment rate of pressure drop, which presented that reducing the pore size distribution range (3σ) can result in low DPF filtration pressure drop. The filtration stage could be further divided into four stages, and the value of particle layer thickness ranging within 15~20 μm has been found to be critical number for the shift from the transient stage to the cake filtration stage. Particle with large primary diameter and BET surface was beneficial to form loose particle layer.

Dynamic Heterogeneous Multiscale Filtration Model: Probing Micro- and Macroscopic Filtration Characteristics of Gasoline Particulate Filters

“…One of the most important parameters to characterize the pore network is the pore size distribution, which can be experimentally measured through mercury intrusion porosimetry . It was found that pore size distributions of particulate filters from porosimetry measurements can be fitted using a log-normal distribution function. ,, On the basis of a recently developed PDF-based statistical approach, a single piece of porous cell is represented by a cluster of spherical collectors, which is modeled by a log-normal distribution function as shown in Figure . In each cell, the total filtration efficiency is calculated as the sum of PDF weighted contributions from all of the collectors with distinct diameters where l dc is a length scale that represents the overall filter collector size and is defined as l dc = [∫PDF d ci · d ci 2 · d ( d ci )] 1/2 .…”

“…Furthermore, the porosity distribution across the filter wall was found to have a significant effect on local flow distribution, filtration efficiency, and pressure drop. 26,53,54 Our previous simulation studies 25 showed that most of particles were deposited at the top slab with a constant or homogeneous porosity, resulting in a high particle concentration gradient near the top surface of the substrate. With an inhomogeneous porosity distribution, the highest concentration of particles was observed at the transition region of the porosity distribution rather than at the top slab.…”

“…59 It was found that pore size distributions of particulate filters from porosimetry measurements can be fitted using a log-normal distribution function. 26,27,30 On the basis of a recently developed PDF-based statistical approach, 28 a single piece of porous cell is represented by a cluster of spherical collectors, which is modeled by a log-normal distribution function as shown in Figure 1. In each cell, the total filtration efficiency is calculated as the sum of PDF weighted contributions from all of the collectors with distinct diameters…”

“…This assumption works well for filtration modeling in DPFs, which are less sensitive to the microstructure of the porous substrate. GPFs are exposed to a larger fraction of ultrafine particulate that can penetrate through the filter due to the absence of a “soot cake” layer as the primary filtration medium. − As a result, the microstructure of the porous substrate is critical, and the interaction between the particulate and the porous substrate has a significant impact on the filtration performance. Moreover, in a realistic filter, the porous substrate has an inherently heterogeneous microstructure that spans a wide range of length scales.…”

Hydrophobic Black Carbon Capture from Ship Emissions Based on a Charger-Coupled Wet Scrubber

“…The nature of the actual ship-emitted black carbon is closely related to the engine type, size, fuel composition, and operational conditions. Studies by Meng et al, − Boger et al, Pfau et al, and other researchers suggest that considering carbon black, notably Printex-U carbon black, as a viable substitute for black carbon (BC) is plausible, particularly in the context of diesel soot exhibiting similar physical traits and featuring high elemental carbon content. This research plays a vital role in the development of ship-based BC emission control.…”