Air Pollution Control Innovations

International Conference on Thermal Treatment Technologies and Hazardous Waste Combustors (IT3/HWC)

Posted by Andy Bartocci on Mon, Aug 26, 2019 @ 01:55 PM

IT3 Logo

Envitech will be attending and exhibiting at the 37th International Conference on Thermal Treatment Technologies and Hazardous Waste Combustors (IT3/HWC) in League City, TX on October 2nd and 3rd, 2019. If you happen to be attending the conference, please stop by the Envitech booth or find me at the conference to say hello.

Three keynote panels will include high level experts and cover hot topics in the industry:

  • PFAS Overview, Regulatory Approach, Testing and Destruction
  • Emerging Air Quality Monitoring
  • Lessons Learned from the United Kingdom's 2018 Novichok Nerve Agent Incident

Papers presented in technical sessions cover:

  • Technologies and Trends in Incineration
  • Plastics Recycle and Reuse
  • Emission Monitoring
  • Waste-to-energy, Emission Monitoring, Pyrolysis 

Envitech will present papers on the following two topics.

Technology Solutions for Sulfuric Acid Formation and Removal in Liquid Waste and Waste Gas Thermal Oxidizers

Petrochemical plants, refineries, and waste-oil re-refiners operate liquid waste or waste gas thermal oxidizers.Candle filter The thermal oxidizers need a wet scrubber to neutralize and remove SO2. Flue gas entering the scrubber contain some sulfur trioxide (SO3) which is converted to sulfuric acid (H2SO4) in the quencher. Sulfuric acid is a submicron liquid aerosol that passes through the downstream packed bed absorber. Some facilities are now being regulated for H2SO4. This paper evaluates and compares candle filters versus wet electrostatic precipitators (WESP’s) for H2SO4 removal in these applications.

Sewage Sludge Incinerator (SSI) Mercury Control Technologies

Mercury Control ScrubberWaste water treatment facilities operating sewage sludge incinerators (SSI) can reduce sludge volume and disposal costs by combusting dewatered sewage sludge. Emissions are regulated by the US EPA Maximum Available Control Technology (MACT) standard 40 CFR Part 60 and 62 to control particulate, lead (Pb), cadmium (Cd), SO2, HCl, dioxins/furans, and mercury (Hg). Many SSI’s need a control device specifically for mercury. This paper evaluates two mercury control technologies: sulfur‐impregnated activated carbon and Gore sorbent polymer catalyst (SPC) modules. Several facilities have used sulfur-impregnated activated carbon but safety issues have arisen due to fires which have shut down some systems. The Gore SPC modules are a relatively new technology with at least seven installations. A comparison is made of capital cost, operating cost, mercury removal efficiency, fire and performance risks based on incineration of 3,000 lbs/hr of sewage sludge. Finally, an overview is provided for an Envitech SPC mercury control scrubber operating at one facility.

Click on the icon below to download an Envitech brochure.

Download Brochure

 

 

Topics: particulate control, Scrubbers, SO2 Scrubber, wet electrostatic precipitators, Acid Gas, Incinerator Scrubber, SO3 Aerosol

Technology Solutions for Sulfuric Acid Formation and Removal in Thermal Oxidizers

Posted by Andy Bartocci on Fri, Aug 23, 2019 @ 05:56 PM

Enivtech will be attending the 2019 International Conference on Thermal Treatment Technologies andCandle filter Hazardous Waste Combustors  (IT3/HWC)  October 2-3 in Houston, TX. A paper will be given on “Technology Solutions for Sulfuric Acid Formation and Removal in Liquid Waste and Waste Gas Thermal Oxidizers”. The paper is available for download by clicking the button at the bottom of this blog piece.

Petrochemical plants, refineries, and waste-oil re-refiners operate liquid waste or waste gas thermal oxidizers. The thermal oxidizers need a wet scrubber to neutralize and remove SO2. Flue gas entering the scrubber contains some sulfur trioxide (SO3) which is converted to sulfuric acid (H2SO4) in the presence of water vapor. Sulfuric acid is a submicron liquid aerosol that can pass through downstream equipment, such as a packed bed absorber or a baghouse. Some facilities are now being regulated for H2SO4.

WESPOver the last decade, Envitech has supplied SO2 scrubbers for thermal oxidizers burning sulfur containing compounds in refining applications. Most of these do not have add-on controls for capturing sulfuric acid mist. More recently, however, Envitech has supplied two systems with candle filters for the capture of sulfuric acid mist. Another known system used a wet electrostatic precipitator for the capture of sulfuric acid mist. A potential fourth system with a large gas flow rate with expected SO3 emissions was evaluated for a wet electrostatic precipitator.

A thermal oxidizer converts sulfur containing liquid or gaseous waste in the presence of excess oxygen to sulfur dioxide (SO2). A fraction of SO2 is further converted to SO3. The reaction is:

SO2 + 1/2O2 => SO3

The conversion amount is influenced by many factors including the thermal oxidizer operating temperature, residence time, sulfur concentration, amount of excess air, and the presence of catalytic oxides and metal catalysts in the fuel. Literature suggests that even a well-performing thermal oxidizer still converts 1 to 5% of SO2 into SO3. Given the numerous factors influencing the formation of SO3¬, most designers select a conservative estimate of SO3 conversion, even when actual SO3 emissions have been measured, as variations in operation can generate substantially higher conversion.

Once formed in the thermal oxidizer, SO3 reacts with water in the downstream quencher to form sulfuric acid (H2SO4) by the reaction:

SO3(g) + H2O(l) => H2SO4(l)

At temperatures below 350°F, H2SO4 condenses into submicron liquid droplets which are difficult to remove because of their small size. Aerosol droplets pass through a quencher and packed bed absorber. A separate control device is needed for sulfuric acid removal that is suitable for submicron droplets.

Click on the link below to download the IT3/HWC conference paper to learn about “Technology Solutions for Sulfuric Acid Formation and Removal in Liquid Waste and Waste Gas Thermal Oxidizers”. The paper evaluates and compares candle filters versus wet electrostatic precipitators (WESPs) for H2SO4 removal in these types of applications.

Download Literature

Topics: particulate control, Scrubbers, SO2 Scrubber, wet electrostatic precipitators, Acid Gas, Incinerator Scrubber, SO3 Aerosol