Issue 11, 2023

Ion density-enhanced electrostatic precipitation using high voltage nanosecond pulses

Abstract

This study evaluates the beneficial effects of discharging nanosecond pulse transient plasma (NPTP) in a coaxial electrostatic precipitator for capturing nanoscale soot particles (∼50 nm) produced by an ethylene flame. Here, the nanoscale soot particles are collected using two different reactor geometries: a 3′′ diameter reactor with a mean flow velocity of 1.2 m s−1 and a 1.5′′ diameter reactor with a mean flow velocity 1.5 m s−1, corresponding to volumetric flow rates of 11.5 CFM and 3.6 CFM, respectively. The nanosecond high voltage pulses (+20 kV, 20 ns, 800 Hz) are applied in conjunction with DC bias voltages. While nearly 100% collection efficiency can be achieved without NPTP at sufficiently high DC voltages (|VDC| > 14 kV), this drops below 50% for lower DC voltages (|VDC| < 10 kV). With NPTP, we observe substantially enhanced remediation (up to 23×) at lower DC voltages (|VDC| < 10 kV) due to the enhanced ion density produced by the plasma. For DC-only electrostatic precipitation, the charging of soot particles takes place via a DC corona, whose ion density is several orders of magnitude lower than that of the NPTP, which produces a streamer discharge due to the fast rise times of the nanosecond pulses (i.e., dV/dt ∼ 1012 V s−1). High speed imaging of the plasma emission profile indicates that ion densities 106 times higher are achieved with the nanosecond pulsed plasma, as compared to that of the DC corona. At lower DC voltages (i.e., |VDC| < 10 kV), the charging of soot particles is a key factor limiting the DC-only remediation efficiencies, and NPTP provides a way to mitigate this limitation.

Graphical abstract: Ion density-enhanced electrostatic precipitation using high voltage nanosecond pulses

Supplementary files

Article information

Article type
Paper
Submitted
31 May 2023
Accepted
06 Sep 2023
First published
29 Sep 2023
This article is Open Access
Creative Commons BY license

Environ. Sci.: Adv., 2023,2, 1566-1573

Ion density-enhanced electrostatic precipitation using high voltage nanosecond pulses

B. Zhang, I. Aravind, S. Yang, S. Weng, B. Zhao, G. Johnson, L. Brown, J. Olfert, H. Jung and S. B. Cronin, Environ. Sci.: Adv., 2023, 2, 1566 DOI: 10.1039/D3VA00148B

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements