EURO-5 norms requires to use the fuels with sulphur content below 10 ppm.

Traditional method of desulphurisation is Hydrodesulphurisation (HDS), which works for vehicle fuels , but have limitations for marine fuels, because the sulphur substances in marine fuels are quite difficult to be removed by HDS.

The Regulation 14.1.3 of Annex VI to the International Convention MARPOL 73/78 as of 01.01.2020 concerning the use of low Sulphur fuel oil (0.50% m/m) on ships will enter into force on 1st January 2020. While ship operates within Emission Control Areas, the Sulphur content in fuel oil used on board ship shall not exceed 0.10% m/m (Regulation 14.4).

Since 1 January 2015 the maximum Sulphur content of marine fuels used in Sulphur Emission Control Areas (SECAs) has been reduced from 1.0% to 0.1%.

According to IMO estimates, the 0.50 per cent Sulphur limit for marine fuels in 2020 will affect as many as 70,000 ships. Choosing the most economically feasible option for compliance is difficult.

Currently the following methods are used and researched:

. Conventional hydrodesulfurization (HDS)

. Oxidative desulfurization (oxidation/extraction) -ODS

. Alternative desulfurization methods such as selective adsorption, biodesulfurization etc

Research laboratories and refineries are spending huge amounts of money in finding a viable and feasible solution to reduce sulfur to a concentration of less than 10 ppm. It presents due to more stringent regulations there is a need for novel technologies for ultra-deep desulfurization so as to produce ultra-low-sulfur fuels.

Usually, the HDS process converts a number of organo-sulfur compounds to H2S and sulphur-free organic compounds. This can be done through catalytic treatment with hydrogen at elevated pressures, between 150 and 3000 psi, and elevated temperatures, between 290 and 455 °C, using metal catalysts such as CoMo or NiMo on alumina substrates.

Refineries may produce the ultra-low sulphur diesel (ULSD), controlling hydrotreating conditions and appropriate catalysts. For diesel, a two-stage deep desulfurization process is sufficient to meet the 10ppm sulphur target. The first stage reduces the sulphur level to below 250 ppm and second stage produces diesel product with 10 ppm sulphur about.

However HDS process is :

. Not very effective for marine fuels as some sulphur substances in marine fuels are inert in HDS process; further cost increase to remove inert substances

. Severe operating process, involving high pressure and high temperature environment

. The process involves hydrogen

. The process involves costly Co, Mo, Ni catalysts

Consequently, there is a significant interest in low-cost desulfurization technologies that might replace or complement hydrodesulfurization.

DHDS is limited in treating BTs and DBTs (especially DBTs having alkyl substituents on 4 and/or 6 positions). The production of light oil with very low levels of sulfurcontaining compounds requires the application of severe operating conditions and the use of especially active catalysts.

Moreover, the HDS process has reached a stage where increasing temperature and pressure are just not enough to remove last traces of sulfur without affecting the octane number.

ODS is a promising technology for the reduction of sulfur at low temperature (∼50 °C) and atmospheric pressure. In ODS, heavy sulfides are oxidized by adding one or two oxygen atoms to the sulfur using appropriate oxidants without breaking any carbon–sulfur bonds, yielding the sulfoxide and sulfone, respectively.

These oxidized compounds are then extracted or adsorbed from the light oil due to their increased relative polarity.

Thus, the ODS is basically a two stage process; oxidation, followed by liquid extraction.

. First, the oxidants chosen do not always perform selectively. Some oxidants cause unwanted side reactions that reduce the quantity and quality of the light oil.

. The second problem is the selection of a suitable solvent for the extraction of the sulfur compounds. Using the wrong solvent may result in removing desirable aromatic/olefinic compounds from the fuel or extracting less than desired amount of the sulfur compounds from the fuel. Reaction selectivity, safety and cost are important concerns for the selection of oxidant, catalyst and operating conditions for ODS processing.

. The catalytic systems reported are mostly toxic and expensive.

. There are issues relating to ultimate fuel quality and economy of the process.

Thus, there is a need for a new technology that can perform the oxidation reaction under mild conditions, and one that can selectively oxidize the sulfur compounds.

The development and application of oxidation/extraction method are considered among the most desired options because they can lower the sulfur without negative impact on capital investment.

1. High consumptions of oxidation agents and inability to regenerate them

2. Timely process

3. Involvement of organic volatile solvents

4. Expensive high speed mixers

5. Considerable losses of the fuel and extraction agent

IODS is completely new approach for desulpfuring through oxidation and extraction, which:

1. Does not involve hydrogen and other volatile and dangerous gases and compounds

2. Does not require high temperatures and high pressures processing environment

3. Does not involve strong acids for oxidation

4. All used chemicals are non toxic and safe

5. The components of oxidation mixture can be easily regenerated

6. Can be realized in block form as not bulky set of the equipment without integration into the structure of the oil processor.

The following products are targeted to be desulpfured under the terms Marine Fuels or Bunker fuels:

. Marine gasoil (MGO)

. Marine diesel oil (MDO)

. Intermediate fuel oil (IFO)

1. Mixture of the fuel with sulphur substances with NSE in temperatures 25оС- 50оС in the proportions from 4:1 to 10:1 , depending on the sulphur compounds content

2. Adding OM components in the same reactor

3. Mixing the mixture for 30-60 minutes

4. Reducing the temperature in the reactor to room temperature, which will lead to separation of the SE and the fuel (almost without sulphur compounds)

5. Additional extraction or adsobtion within 1-2 minutes for removing of the soluble compounds

6. Removing of NSE and its regeneration

New technology belongs to modified ODS group.

. New technology allows to remove 99.5%+ of all sulphur compound.

. New technology includes special oxidation mixture (OM), which transfer the sulphur containing substances, soluble in the fuel, to sulfones and sulphur oxides, which do not dissolve in the fuels.

. New technology includes also New Special Extragent (NSE), which allow effectively remove the non soluble sulphur compounds from the fuel.

. The OM and NSE allow the oxidation\on and extraction processes to be performed within one chamber in the frames of the single process.

. Both OM and NSE are the results of many years of original research and not available in the common market, though are not expensive , non toxic, substances, which is the proprietary knowledge and the intellectual property of the Authors of the invention.

. NSE and OM components can be regenerated for few times (5-6) on the customer site.

. New Technology is operating in the temperature range 25оС- 50оС in normal atmospheric pressure , not involving DG, harmful, toxic, explosive corrosive substances.

. The removed sulphur is bound to non toxic , non soluble in water, stable sulfone substances, which create zero effect on the ecology.

1. NSE reacts with broad spectrum of the sulphur compounds

2. NSE absolutely not extracting and reacting with the fuel leading to zero loss of NSE after the process

3. The viscosity of NSE drops even due to temperature rise, easing the mass transfer

4. NSE is stable chemically inert , even on high temperatures

5. Some special additives to NSE allows switch its properties, i.e to be non reactive and non mixable with the fuel below certain set temperature and be homogenic once the temperature of the solution is raised