ON THE CHOICE OF RAW MATERIALS PREPARATION TECHNOLOGY FOR CATALYTIC CRACKING JSC «GAZPROM NEFTEKHIM SALAVAT»
There is a tendency to use in the processes of hydrocracking and catalytic cracking weighted feedstock (deep vacuum gas oils, DAO, fuel oil and even tar) for the problem solution to deepen oil processing. Rapid catalyst poisoning weighted raw material leads to a deterioration quality of products and reduce turnaround facilities. These factors have stimulated interest for the pre-treatment of raw material processes. It allows to obtain materials with improved characteristics.
The work is devoted to the choice of the most efficient and economic expediency raw feedstock preparation technology for the construction of a catalytic cracking unit at JSC «Gazprom neftekhim Salavat». We offer to use heavy oil residues (tar installation CDU-AVT-6) as a component of the raw feedstock of the process after their preparation, that will increase the depth of oil refining.
We considered technologies such as thermal adsorption tar deasphalting, tar deasphalting with hydrodesulphurization DAO, hydrodesulphurization tar in «bin» type reactor and hydrodesulphurization tar with a three-phase fluidized catalyst bed. Material balances processes was represented in the work. We used as the raw material tar with an initial boiling point > 520 °C for calculations. Performance settings defined in 1623600 tons / year, which corresponds to the development of tar on the installation CDU-AVT-6 OJSC «Gazprom Neftekhim Salavat». Also in the work were represented product quality assessment calculation of technical and economic indicators product quality.
It found that the technology of hydrocracking tar with a three-phase fluidized catalyst bed like «H-oil» can be the most advantageous process for the preparation of catalytic cracking feedstock JSC «Gazprom neftekhim Salavat» from tar mixture of Western Siberian oil and rational use of the received light fractions and residue This technology has a number of advantages: a high yield of low-sulfur distillate products, the possibility of deep processing of oil residues and other heavy hydrocarbons, to obtain high quality raw materials for catalytic cracking and coking processes, safety, reliability, ease of installation. The cost price of production will be about 9300 rub./ t.
The most common method of gas purification from acidic impurities is cleaning with amines-natural organic compounds that are derivative of ammonia. Amine purification is a regenerative process. Absorption of acidic pollutants occurs approximately ambient temperature Wednesday, and Amina regeneration occurs at boiling point in stripping column. The disadvantage of the process natural and technological gases from acidic impurities is the large amount of heat required to desorption. The most common and effective method for purification of gas currently cleaning using alkanolaminov. This process differs with the opportunity to achieve a high degree of purification at relatively low cost. Gas purification schemes to reduce heat flow supplied to the bottom of the stripping column, were simulated in the package Unisim Design: standard process flows, Division steam, their combination of recompression. Also offers purification scheme when using a mixture of amines (DEA + MDEA). Method of combining schemes and Division of flow helps reduce the heat load compared with the method of replacing monoethanolamine on 23%, but the method of steam recompression has a lower heat load compared with replacement of monoethanolamine-on 30%.Other options for change process flow diagrams are associated with large capital costs. Thus, the proposed scheme with steam recompression will reduce the heat load with relatively small capital cost.
Examines different numerical methods and problems of calculation of the rectification columns. The solution of problems in the transition from simple to complex columns, the presence of water in the system of rectification, taking into account the heat balance calculation. Discuss various algorithms of calculations and designed application package for span and design calculation of complexes of columns, to determine the quantity and quality of products, the heat load on the equipment, water vapour consumption thermophysical characteristics of streams and hydrodynamic loads on elements of columns. A pack of five programmes and databases implemented on Turbo Pascal language and updated on the use of languages-Python and c++.
Settlement analysis of industrial fractions equipment allows to develop recommendations for improving the efficiency of mass transfer devices, increasing the depth of selection target components and fractions, improving the quality of the products division, as well as lower energy costs.
Developed software package implements functions that allow various functions for calculating industrial equipment and on-line to create input file and generate a table of results that enable the development of recommendations to reduce the cost, increase the depth of selection, quality and energy efficiency mass exchange devices.
Using pinch analysis considered the scheme elou-at-3 with a capacity of 3 million tons/year. During the work of the new scheme was proposed strapping heat exchangers, which when compared with the existing is better. When moving to the proposed scheme of heat increased raw materials supply temperature in oven with 240 to 250 °C, allowing decreased fuel consumption in a furnace at 309 kg/h, and therefore reduced the cost of heating fuel.
The most significant role of heat exchange units AT and plays AVT, blocks heat transfer which due to the large amount of heat is the most complex systems.
Pinch analysis is one of the best methods for analysis of heat transfer systems in the chemical and petrochemical industry, and is based on thermal analysis system process flows.
For refining and petrochemical enterprises, most of which launched in 60-70 last century, the use of pinch technology allows achieving reduction of energy consumption and, consequently, financial payments behind them, 30-50%, and in some cases on separate installations to 70%.
The program that implements the calculation by the method of Pinch analysis allows you to make data-based computation to build composite curves of hot and cold streams.
Buildings show the possibility of increasing the maximum heat recovery. This enables you to optimize the heat flows in the hardware and choose the most efficient schemes of heat exchange.
Utilization and use of associated petroleum gas is an important task of oil and gas companies. Therefore, the use of low-cost and effective technology solutions will enable oil companies to increase the utilization of associated petroleum gas. One of the methods of development of associated petroleum gas treatment technology is the use of low-temperature supersonic gas-dynamic separation.
That technology based on the passage of gas stream through supersonic nozzle. The adiabatic gas expansion results in deep gas cooling due to heat energy of gas transforms into stream kinetic energy. When gas stream direction changes condensed components are dropped to the inner wall and removed by centrifugal force.
Valuable components recovery (C3+) and meeting hydrocarbon dew point and water dew point temperatures of transported gas are the main ways to use supersonic technology today.
The article discusses the effects of inlet stream pressure and temperature changing, pressure drop through the separation device changing and the composition of the stream changing on supersonic separation. Study has been conducted using UniSim Design R400 software.
Knowing the nature of process parameters impact on process outcome it is possible to predict products quantity and quality and the applicability of the process with some accuracy. Simulation allows to adapt design facilities of device to specific conditions of gas purification and drying process, also it becomes possible to optimize process parameters for sufficient gas components production.