Scientific journal

Modern high technologies

ISSN 1812-7320

"Перечень" ВАК

ИФ РИНЦ = 0,940

In a modern competitive economy conditions, every refinery set as a main goal the providing of domestic and foreign market with high-quality gasolines and in the same time reducing costs for their production. So the much attention is paid to the blending process, as a process of production of high-quality gasolines by blending of straight-run oil fractions with secondary refining processes components and special additives. During this process, the qualitative and quantitative characteristics of gasoline are determined.

The blending process is extremely difficult for optimization, due to factors [1]:

– The large number of components;

– Deviations from additivity of physical and chemical properties of the mixtures components;

– Difficulties of developing mathematical models which adequately describe the process in wide range of components properties variations.

– Permanent changes of the raw materials composition.

So for the optimization of the blending process, a deep knowledge of physical-chemical basis of the process both mathematical models applying, as an effective solving method of these multi-factorial and multi-criteria optimization tasks, are strongly required.

The department of Chemical Technology of Fuel and Chemical cybernetics proposed the new approach for the calculating of gasoline blending process, with applying of computer modeling system. It was revealed, that differences in the properties of individual components in a free condition and in mixtures with other hydrocarbons take place in every stream. It is caused by mutual influence of the atoms and molecules and, as a fact, changing their conditions. [2, 3].

On the basis of this theory the computer modeling system of blending process «Compounding» was developed. Its main purpose is to calculate octane numbers of trade gasolines produced with the blending method.

The input data for the calculations in this program is the chromatography analysis data of streams, involved in the blending process. Due to lack of unified standardized methodology results presenting, experimental chromatography analysis data from the refineries is significantly different. As the developed computer modeling system is used to calculate the blending process in various refineries, it is necessary to form a unified representation of input data. For this aim, the module of automatic systematization of chromatographic analysis data is implemented in the «Compounding» system. The base of systematizing is the set of 69 hydrocarbons, except olefins (set №1 in table 1).

Table 1

The content of automatic chromatography analysis data systematization module

Olefins are contained in significant amount in the products of deep oil treatment processes as catalytic cracking and coking. In the same time, these products are involved in the production of trade gasoline and this involving is tend to be increased every year. Thus, olefins make a significant contribution in the final octane rating of every gasoline’s mixture, which can’t be ignored; therefore expanding the set of components is the necessary step of research.

There are 7 main gasoline streams, involved into the analysis: products of moving bed catalytic reforming process; catalytic cracking gasoline; products of fixed bed catalytic reforming process; alkylate; natural gas gasoline; isomerizate.

The development of the extended formalized set of 110 hydrocarbon components means the aggregation of all individual components, appeared in chromatograms. Aggregation of components was based on four criteria:

– hydrocarbons group affiliation;

– similarity of concentrations;

– similarity of hydrocarbon molecule structures;

– similarity of components octane numbers;

The main aim of aggregation is to create a set, which must be the lowest possible by the number of components and, at the same time, provides streams octane numbers calculating with maximum precision. This way the final set of hydrocarbon components for the automatic systematization of chromatographic analysis data was created. The set №2 includes 110 components, including olefins (table 1).

As the adequateness test, octane numbers of streams with the known detonation characteristics were calculated applying the created set of components. Analysis of results reveals that the proposed method allows calculating the octane numbers with an absolute error of no more than 1 point. This is comparable with the error of experimental methods of this parameter determination.

On the basis of the created set, a computer module of automatic chromatography analysis data systematization is realized. The main program unit is developed in Borland «Delphi 7» workspace, which provides an opportunity to develop a user-friendly interface in a short-time period, without losing its functionality.

In conjunction with the program «Compounding» module provides precisely counting detonation characteristics of gasoline, both it helps to respond the feedstock composition changes, to vary the trade gasolines blending recipes and to recommend optimal involving of different in composition feedstock into the blending process.

Blending recipes examples for gasolines Premium-95 and Super-98, corresponding to modern Euro-3, Euro-4 and Euro-5 gasoline quality standards (table 2), were created.