Find results with:

Add another field

Search by date

to

Searching collections:

Dartmouth Dissertations

Add or remove collections

Home Dartmouth Dissertations Page 1

Reference URL

To link to the entire object, paste this link in email, IM or document

To embed the entire object, paste this HTML in website

To link to this page, paste this link in email, IM or document

To embed this page, paste this HTML in website

The chemistry of arsenic and mercury under post-combustion conditions.

you wish to report:

Your comment:

Your Name:

Submit

Cancel

...

Back to top

Powered by CONTENTdm®

Call No.	Ph.D. 2010
Author	Smith, Clara A.
Title	The chemistry of arsenic and mercury under post-combustion conditions.
Date	2010
Abstract	Coal combustion remains an important source of toxic metal emissions. Dilute concentrations and poor understanding of their chemistries hinders reduction of these emissions. This thesis examines the chemistry of the trace metals arsenic and mercury in coal combustion systems to help provide guidance toward improving emission control strategies. While studies in the literature examine coal arsenic chemistry, vaporization of arsenic, interaction between arsenic and solid materials, and partitioning of arsenic in fly ash are not well understood. Synthetic char combustion experiments showed that gas-solid reactions of arsenic and calcium likely occur externally of char particles and the reactions rates reported in the literature are slower than that which occurs during combustion. As hypothesized, As 4 O 6 was only found in the sub-micron fly ash, likely from condensation. This information was used in a mathematical model of arsenic partitioning in fly ash. Simulations show that arsenic in sub-micron fly ash particles is present from condensation of As 4 O 6 , while arsenic in super-micron fly ash particles is present from arsenic that remains un-vaporized during the combustion process. Mercury studies in the literature address aspects of coal mercury chemistry, however, the effects of flue gas constituents on mercury oxidation are not well understood. In homogeneous experiments, mercury oxidation levels increased with increasing HCl concentrations, while oxidation in the presence of increasing SO 2 concentrations remained consistent. When both HCl and SO 2 were present, mercury oxidation was enhanced at an HCl concentration of 200 ppmv and inhibited at an HCl concentration of 555 ppmv. In heterogeneous experiments, mercury oxidation was enhanced from the homogeneous experiments at high hematite particle concentrations in the presence of HCl alone and in the presence of SO 2 alone at a concentration of 500 ppmv. Experiments conducted in the presence of montmorillonite particles showed that increased oxidation was not due solely to injected particles.
Description	xxvi, 400 leaves : ill. ; 28 cm.
Format	application/pdf
Advisor	Helble, Joseph J., Lynd, Lee R., BelBruno, Joseph, Wendt, Jost OL
Subject	Arsenic wastes -- Analysis. Mercury wastes -- Analysis. Coal -- Combustion -- By-products. Fly ash. Flue gases.
College	Thayer School of Engineering.
Issuing Body	Dartmouth Dissertations are made available through the Dartmouth Digital Library.
Degree	Thesis (Ph.D.)--Dartmouth College.
Copyright	All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means without permission in writing from the author.
DOI	http://dx.doi.org/10.1349/ddlp.405

Title	Page 1
Format	application/pdf
Issuing Body	Dartmouth Dissertations are made available through the Dartmouth Digital Library.
Degree	Thesis (Ph.D.)--Dartmouth College.
Full Text	THE CHEMISTRY OF ARSENIC AND MERCURY UNDER POST-COMBUSTION CONDITIONS A Thesis Submitted to the Faculty in partial fulfillment of the requirements for the degree of Doctor of Philosophy by CLARA A. SMITH Thayer School of Engineering Dartmouth College Hanover, New Hampshire January, 2010 Examining Committee: Chairman: Joseph J. Helble, Ph.D. Member: Lee R. Lynd, Ph.D. Member: Joseph BelBruno, Ph.D. Member: Jost O.L. Wendt, Ph.D. Brian W. Pogue Dean of Graduate Studies

Find results with:

Searching collections:

Home Dartmouth Dissertations Page 1

The chemistry of arsenic and mercury under post-combustion conditions.

Object Description

Description

The chemistry of arsenic and mercury under post-combustion...

The chemistry of arsenic and mercury under post-combustion...

	All
	Pages Enter page numbers or page ranges separated by commas. For example: 1,3,5-12