(67d) Technology Opportunities for Reduction of Emissions from Sulfuric Acid Manufacturing Plants

Heterogeneous catalysis is a very important
technology for manufacture of various commercial and end-user products due to
its significant economic and environmental impact. In 2012, the commercial
value of annual catalyst production was estimated to be approximately 14 MMM US
dollars with more than 85% of all chemical commodities are manufactured using
catalysis¹.

      H₂SO₄
catalysis has intrigued researchers and scientists for centuries due to the process
economics, various complexities and environmental impact. H₂SO₄
is a very important chemical commodity since a nation's acid production has
been used as a reasonably good indicator of its industrial strength for the
last century or so^2,3.  Nearly 350 MM tons of H₂SO₄
were produced in 2014⁴.  Rising
demand for commercial and sustainable process technologies for H₂SO₄
production is the primary driving force for industrial R&D to provide
state-of-art technologies.  Both sulfur
and H₂SO₄ as raw materials have been the subject of
various annual and biannual conferences^5,6,but limited open literature exists on the economics and technical
advancements of H₂SO₄ manufacture with most data kept as
company proprietary.

      From an environmental
perspective, SO₂ is identified as one of the ?criteria air pollutants?
by Environmental Protection Agency (US EPA). 
These pollutants can cause harm to human health, environment and also
cause property damage. Therefore, the EPA regulates these pollutants by
development of human-based and/or environmentally-based criteria to set permissible
levels. The catalytic oxidation of SO₂ to SO₃, which is
heart of the H₂SO₄ production process, is always
incomplete due to equilibrium limitation. Hence, unconverted SO₂ emissions
have to be controlled to meet environmental regulations before released into
the atmosphere.

      Figure 1 is the schematic
representation of the three main facets of H₂SO₄
catalysis for sulfuric acid manufacturing plants. These technological areas are
(1) catalysts used for SO₂ oxidation^7,8;
(2) process technologies used for different aspects of H₂SO₄
manufacturing such as preheating feed gases, dry gas SO₂ oxidation,
wet gas process, SO₃ mist control and optimal heat recovery systems^9,10,11;
(3) End-of-pipe control technologies, such as scrubbing of unconverted SO₂
in stack gases and recycling weak H₂SO₄ for better waste
management¹².

Figure 1.
The three faces of H₂SO₄ catalysis for H₂SO₄
plants^13,14.

The primary objective of this presentation is to provide an overview of current
processes for sulfuric acid process production and the current status of
next-generation clean technologies for reduced emissions of SO₂ from
H₂SO₄ acid manufacturing plants to meet future more stringent
environmental regulations.  Emphasis will
be placed on opportunities for development of new particulate and monolith
catalyst technology having improved performance.  An example of modeling of transport-kinetic
interactions in 3-D multi-lobe catalysts using the Dusty Gas model is shown in
Figure 2 where the concentration and temperature profiles are compared for two
different catalyst shapes.

Figure 2. Concentration and
Temperature profiles for Rounded step and Light bulb

                  shapes
using Dusty Gas diffusion model

References

1.      Heveling, J. (2012). "Heterogeneous Catalytic
Chemistry by Example of Industrial Applications." Journal of Chemical
Education 89(12): 1530-1536.

2.     
Muller, T. L.
(2000). Sulfuric Acid and Sulfur Trioxide. Kirk-Othmer Encyclopedia of
Chemical Technology, John Wiley & Sons, Inc.

3.     
ChemSystems
(2009). PERP program sulfuric acid report abstract.

4.      IHS (2014). Sulfuric Acid. Chemical
Economics Handbook.

5.     
CRU, G. (2013).
Sulphur, sulphur acid, sulphur dioxide.

6.     
Sulphuric-acid.com.
(2015). "Industry Conferences."  
Retrieved May 2015, 2015, from

http://www.sulphuric-acid.com/sulphuric-acid-on-the-web/conferences.htm.

7.     
Haldor-Topsoe.
(2015). "Sulfuric Acid."  
Retrieved May 2015, 2015, from http://www.topsoe.com/processes/sulfuric-acid.

8.     
MECS. (2015).
"MECS® Sulfuric Acid Catalyst Products." from http://www.dupont.com/products-and-services/consulting-services-process-technologies/brands/sustainable-solutions/sub-brands/clean-technologies/uses-and-applications/mecs-catalyst.html.

9.     
Laursen, J. K.
(2007). "The Process Principles, Detailed Advances in Sulfur Recovery by
the WSA Process." Hydrocarbon Engineering 12: 47-51.

10.  MECS. (2015). "MECS® SULFOX? Wet Gas Sulfuric
Acid Process."   Retrieved May 2015,
2015, from http://www.dupont.com/products-and-services/consulting-services-process-technologies/brands/sustainable-solutions/sub-brands/clean-technologies/products/mecs-sulfuric-acid-environmental-technologies/sub-products/mecs-sulfox.html.

11.  MECS. (2015). "MECS® Brink® Fiber Bed Mist
Eliminators."   Retrieved May 2015,
2015, from http://www.dupont.com/products-and-services/consulting-services-process-technologies/brands/sustainable-solutions/sub-brands/clean-technologies/products/mecs-sulfuric-acid-environmental-technologies/sub-products/bed-mist-eliminator-products.html.

12.  MECS. (2015). "MECS® DynaWave® Wet Gas
Scrubber."   Retrieved May 2015,
2015, from http://www.dupont.com/products-and-services/consulting-services-process-technologies/brands/sustainable-solutions/sub-brands/clean-technologies/products/mecs-sulfuric-acid-environmental-technologies/sub-products/dynawave.html.

13.  MECS (2015). ?How DynaWave
works.? Retrieved May 2015, from

http://www.mecsglobal.com/howthe-dynawave-wet-gas-scrubber-works.aspx

14.  Kiss, A. A., C. S. Bildea, et al. (2010).
"Dynamic modeling and process optimization of an industrial sulfuric acid
plant." Chemical Engineering Journal 158(2): 241-249.