Many options are available for treating sour gases, so consideration must be given to the type of by-product (sulphate effluent, sulphur or sulphuric acid), local markets for these products, shipping costs, overall sulphur recovery required and economics. The Claus SRU process is clearly the predomi¬nant choice for treating acid gases, presumably due to the well-established sulphur marketing and shipping infrastructure, ease of handling and economics. However, converting acid gases to sulphuric acid with technologies like the MECS SULFOX process presents an interesting option when sulphuric acid end-users are nearby or the acid gas characteristics make processing in a Claus SRU unit unattractive

1. ACHIEVE 99% SULPHUR RECOVERY AS SULPHURIC ACID IN ITS SIMPLEST CONFIGURATION.
Dr. Rania Farouq Abdou
Ahmed Sharif
Amr Elshaikh
Mohamed Asaad
Magdy Zaref
Moataz Satour

2. Dr. Rania Farouq Abdou
1
TREATMENT OF N.G
BY SULFOX
ACHIEVE 99% SULPHUR RECOVERY AS
SULPHURIC ACID IN ITS SIMPLEST
CONFIGURATION.
Introduction
SULFOX process is one of the methods of treating Natural Gas,
and it’s a DIRECT CONVERSION PROCESS.
What is sulfox process?
Sulfox is a gas desulfurization process which converts sulfur that
is in raw gas to concentrated sulfuric acid.
Main features:
1. Catalytic oxidation of the sulfur compounds to SO3 and
formation of sulfuric acid
2. Various types of plants for a wide range of raw gas
concentrations
3. High efficiency of the noble metal catalyst
4. Recovery of commercial grade sulfuric acid
5. No usage of chemicals, no emission of toxic substances.
1. Operate the
facility
continuously and
reliably
2. Economically
create products
meeting the
market’s quality
standards
3 .Sell the products
to the market

3. Dr. Rania Farouq Abdou
2
Operation-Technology
MECS® SULFOX™ : A SULFOX sulphuric acid plant can achieve 99% sulphur
recovery as sulphuric acid in its simplest configuration.
More complicated flow schemes utilising activated carbon filters or a DynaWave tail gas
scrubber can achieve much higher sulphur recovery values and
ultra-low SO2 emissions.
A SULFOX plant can be installed in lieu of a Claus SRU and TGTU or as part of an
integrated complex with a new or existing Claus SRU and
TGTU.
When integrated in this way, a SULFOX plant increases flexibility and reliability by
debottlenecking acid gas capacity, processing SWS gas to
eliminate ammonia concerns, providing additional Claus SRU
tail gas clean up, and handling all acid gas when the Claus SRU
is down.
process
1. The feed gas, after being oxidised to SO2 and brought to the correct temperature.
2. passes through a converter containing vanadium and caesium-promoted catalyst and
internal heat exchangers.
3. The equilibrium reaction of SO2 to SO3 occurs across multiple catalyst beds.
4. with heat exchangers removing the reaction heat between each bed to increase the
SO2-to-SO3 conversion level.
5. The final heat exchange step in the converter lowers the process gas temperature to a
level above the sulphuric acid condensation point (acid dewpoint).
6. and the gaseous SO3 reacts with H2O vapour to form sulphuric acid vapour.

4. Dr. Rania Farouq Abdou
3
PROCESS CONDITIONS
The feed gas oxidation, and heating or cooling steps of a SULFOX plant depend on the acid
gas concentration and composition. For applications with >5 vol% H2S or significant quantities
of hydrocarbons or ammonia, a SULFOX HK process thermally oxidises the feed gas at high
temperature.
SULFOX HK process & SULFOX NK process
The HK-type plant provides the maximum feed gas flexibility at the trade-off of a larger, more
expensive and complicated plant due to the combustion and steam systems. An NK-type plant
offers a simple, inexpensive, and reliable process but places limits on the allowable feed gas
composition.

5. Dr. Rania Farouq Abdou
4
A SULFOX HK process suits most acid gas treatment facility applications. Table 4 highlights
the relative comparison for a lower concentration H2S acid gas feed, which would require
modifications to a typical Claus process to reliably treat. The SULFOX process offers
substantial capital and operating cost benefits compared to a Claus SRU and TGTU
combination.
Process Benefits
1. Process Benefits: Recovery and recycle of SO2 to the Claus SRU
1) Provides attractive debottlenecking and expansion opportunities in the Claus SRU for
existing facilities
2) Reduces capital expense and plot space requirement for grassroots facilities
2. Solvent Benefits: Unique absorption solvent
a. Readily available and cost-effective
b. Environmentally friendly
c. Virtually eliminates waste associated with traditional scrubbers
3. Guaranteed ultra-low SO2 emissions (less than or equal to 20 ppmv SO2)
Summary
Many options are available for treating sour gases, so consideration must be given to the type
of by-product (sulphate effluent, sulphur or sulphuric acid), local markets for these products,
shipping costs, overall sulphur recovery required and economics.
The Claus SRU process is clearly the predominant choice for treating acid gases, presumably
due to the well-established sulphur marketing and shipping infrastructure, ease of handling
and economics. However, converting acid gases to sulphuric acid with technologies like the
MECS SULFOX process presents an interesting option when sulphuric acid end-users are
nearby or the acid gas characteristics make processing in a Claus SRU unit unattractive.