Low pressure drop static mixing system

A method, comprising:

• receiving a contaminated gas stream comprising a contaminant;
• introducing an additive into the contaminated gas stream, the additive at least partially removing or causing the removal of the contaminant
• passing the additive-containing contaminated gas stream through an in-line mixing device, positioned in a duct containing the additive-containing contaminated gas stream, to form a turbulent contaminated gas stream, wherein, in a first operating mode, the in-line mixing device has a first position relative to a direction of flow of the additive-containing contaminated gas stream and, in a second operating mode, the in-line mixing device has a different second position relative to the direction of flow of the additive-containing contaminated gas stream and wherein one or more of the following is true:
• (a) the first operating mode provides a first pressure drop of the additive-containing contaminated gas stream passing the in-line mixing device and the second operating mode provides a second pressure drop of the additive-containing contaminated gas stream passing the in-line mixing device, the first pressure drop being greater than the second pressure drop;
• (b) the first operating mode provides a first level of turbulent flow of the additive-containing contaminated gas stream passing the in-line mixing device and the second operating mode provides a second level of turbulent flow of the additive-containing contaminated gas stream passing the in-line mixing device, the first level of turbulent flow being greater than the second level of turbulent flow;
• (c) in the first operating mode, a plane of a face of the in-line mixing device has a first angular orientation relative to a direction of flow of the additive-containing contaminated gas stream and in the second operating mode the plane of the face of the in-line mixing device has a second angular orientation relative to the direction of flow of the additive-containing contaminated gas stream, the first and second angular orientations being different;
• and
• (d) in the first operating mode and during a selected time interval, a first amount of the additive-containing contaminated gas stream passes through the in-line mixing device and, in the second operating mode and during the selected time interval, a second amount of the additive-containing contaminated gas stream passes through the in-line mixing device, the first amount being greater than the second amount;
• and
• thereafter removing, by a particulate control device, particulates from the additive-containing contaminated gas stream, wherein the particulates comprise at least some of the contaminant and/or a derivative thereof.

A method, comprising:

• receiving a contaminated gas stream comprising a contaminant;
• introducing an additive into the contaminated gas stream, the additive at least partially removing or causing the removal of the contaminant;
• determining, by a computer, a desired flow resistance and/or pressure drop across an in-line mixing device positioned in the contaminated gas stream to distribute the additive throughout the contaminated gas stream;
• determining, by the computer, a desired orientation of the in-line mixing device and/or a mixing element thereof relative to a flow path of the contaminated gas stream to produce the desired flow resistance and/or pressure drop across the in-line mixing device;
• determining, by the computer, a current orientation of the in-line mixing device and/or a mixing element thereof relative to a flow path of the contaminated gas stream, wherein the current and desired orientations are different;
• causing, by the computer, the in-line mixing device to change from the current orientation to the desired orientation;
• and
• removing, by a particulate control device, particulates from the contaminated gas stream, wherein the particulates comprise at least some of the contaminant and/or a derivative thereof.