Combined Processing of Wide Naphtha IBP-180°С
Modern motor gasoline standards set new requirements to wide naphtha processing technologies. Analysis of existing naphtha processing scheme at operating refineries is represented below.
The most common wide naphtha processing scheme on a refinery is naphtha separation into feed of pentane-hexane fraction isomerization and reforming feed. The main disadvantages of such scheme are:
- high content of benzene in autocomponent (1.4-1.8 %);
- high content of aromatic hydrocarbons (42-44 %);
- yield of total catalyzate per feed is no more than 85-86 %.
In order to meet modern requirements to benzene content of < 1 % and aromatics of < 35 % in commercial motor gasoline, it is necessary to add large amounts of high octane non-aromatic additives (MTBE, alkylate). Nowadays EURO-4 and EURO-5 motor gasoline is produced according to such technology. However, due to the limited amount of high-octane non-aromatic autocomponents, motor gasoline production according to EURO-4 and EURO-5 standards, as a rule, doesn’t exceed 40-50 % from all the range and in a number of cases it is considerably less. There are technical solutions to decrease benzene content in reformate by fractionation and benzene concentrate recovery. However, such solution requires further processing of benzene cut and leads to additional costs, as well as significant decrease of target product yield.
SIE Neftehim, LLC offers technologies proved via commercial and semi-commercial testing, which make it possible to minimize application of additional expensive non-aromatic components in EURO-5 gasoline production and enhance yield of commercial products.
Complex wide naphtha processing scheme under SIE Neftehim, LLC technology is represented below:
The main specific feature of the technology is С7–fraction recovery and its isomerization on a separate unit under the technology developed by SIE Neftehim, LLC.
Involvement of С7 – fraction into isomerization processing scheme allows:
- ensuring the guaranteed benzene content of less than 1 vol. % and decreasing the content of aromatics till 35 %;
- ensuring effective operation of IBP-70°С fraction isomerization catalyst due to decrease of С7+ hydrocarbons in feed;
- enhancing catalyst service cycle, yield, and octane number on reforming unit;
- increasing the yield of commercial motor gasoline due to higher selectivity of С7-fraction isomerization process as compared to reforming.
Thanks to the new integrated wide naphtha processing scheme, Euro-5 requirements are met by compounding only isocomponents and reformate, which significantly decreases costs for obtaining high-octane non-aromatic autocomponents.