Sulfuric Acid Alkylation Of Isobutane Research Articles

Optimization of the content of isobutane in the feed stream of the plant for sulfuric acid alkylation of isobutane with olefins

The raw materials for the industrial production of moto- and air-alkylates are isobutane and butane-butylene fractions containing in their composition a component, n-butane, which is inert for the reaction of sulfuric acid alkylation of isobutane with olefins. In accordance with the Specifications TU 0272-024-00151638-99, the content of n-butane in the isobutane fraction, depending on the grade of the fraction, is 0.7÷20% wt. Its presence reduces the useful reaction volume of the alkylation reactor, and when separating the components of the alkylation reaction mass, it is necessary to use a distillation column (debutanizer). The possibility of including an additional column in the technological scheme for removing n-butane from the composition of the fraction (respectively, isobutane concentration) before it is fed into the alkylation reactor is being considered. This is of particular importance for factions with a brand below "High Brand". The study is conducted using the Honeywell UniSim Design software system. The Peng-Robinson method was used to calculate the properties of process stream components. The theoretically optimal design of the apparatus was calculated: when using a distillation column with a pressure in the apparatus of about 400 kPa to reduce the content of n-propane in the distillate (obtained isobutane fraction) to 0.001 mol. the share will require 48 theoretical plates, the accepted reflux ratio R = 8.9, the temperatures in the condenser and reboiler are 26.88 and 47.27 °C, respectively. A computational experiment has shown that in order to achieve the practical absence of n-butane in the obtained isobutane fraction (concentration of about 0.1% wt.), it is possible to use a distillation column with the following technological modes: the number of plates is 60, the feed plate is 15, the efficiency of contact devices is 0.8; the pressure in the column is about 400 kPa, the temperature in the condenser and reboiler is Тk=28.91÷29.05 ℃ and Тр=46.72÷47.25 ℃, respectively, reflux ratio R=20.41. This fraction also does not contain pentanes.

New type jet turbulent contactor for sulfuric acid alkylation of isobutane with olefins

The modernization of the reactor equipment for the industrial process of sulfuric acid alkylation of isobutane with olefins is considered.

Optimal Control of the Separation Process with Flow Restrictions

Here we formulate the problem of optimal process control with distributed parameters, taking into account the constraints on the control and associated flows. The necessary optimality conditions are obtained. The analysis of the stationarity conditions is carried out and the method for constructing the domain of admissible controls is proposed. The developed optimization method is applied in the automation of industrial distillation plants for the sulfuric acid alkylation of isobutane with butylenes, ortho-xylene production, etc.

Comparative Advantages of Diffusion Modes in Chemical Technology

It is believed that the organization of industrial processes should strive to enable chemical reactions in the kinetic regime. In this study, examples showing how the diffusion regime can be more profitable in terms of improving product quality and process parameters have been given. When formaldehyde is polymerized, the diffusion regime allows increasing the molecular weight of the product. In the case of sulfuric acid alkylation of isobutane with butylenes in the diffusion mode, the yield of the product, the octane number, and the consumption of the catalyst decrease.

Kinetics Study of Sulfuric Acid Alkylation of Isobutane and Butene Using a Microstructured Chemical System

The kinetics of sulfuric acid alkylation of isobutane and 2-butene was first determined using a microstructured chemical system, which shows obvious advantages for fast reactions. The concentration of key components, including trimethylpentane (TMP), dimethylhexane (DMH), light end (LE), and heavy end (HE), were obtained at different reaction temperatures. A kinetics model, containing kinetics parameters of both main and side reactions, was established to predict the alkylation process in the microstructured chemical system. The model fitted with the experimental data very well and was further confirmed by the simulation results calculated with COMSOL software. Compared with the kinetics parameters determined in a traditional batch reactor, the model developed in this work is much more reliable to describe the reaction, because a much shorter reaction time, faster mass transfer rate, and precise control of the reaction time have been reached.

Process Intensification of Sulfuric Acid Alkylation Using a Microstructured Chemical System

To realize process intensification of clean fuel production is becoming a hot topic for sustainable development. This work presents a new intensification technology of sulfuric acid alkylation of isobutane and butene using a microstructured chemical system. A microstructured chemical system has been designed and constructed. The reaction performance was determined, and the effect of acid concentration, phase ratio, reaction temperature, and ratio of isobutane to butene (I/O) were investigated carefully. The results show that the microsturctured chemical system could obviously improve the quality of alkylates with much smaller size reactor and much shorter reaction time for better transport performances. The conversion of olefin could be as high as 100% within 30 s. The selectivity of C8 was 71% with a research octane number (RON) 94.4 under the 94 wt % H2SO4. No obvious changes of H2SO4 concentration was observed after several cycles, indicating that the acid consumption could be effectively reduced in th...

The formation of emulsions during the jet mixing of reagent flows as applied to the sulfuric acid alkylation of iso-butane with olefins

The modernization of reactor equipment for the industrial process of the sulfuric acid alkylation of iso-butane with olefins has been considered. Classic alkyl gasoline production technology has been improved by applying small reactors with a divergent-convergent configuration that optimizes the hydrodynamic regime in the reaction space. This emulsion process is subjected to theoretical analysis with the substantiation of the proposed contactor design. Industrial tests that confirm the high efficiency of the applied design compared to the functioning industrial sulfuric acid alkylation processes with regard to the reduction of energy consumption and the optimization of the consumption parameters of feedstock components and a catalyst have been described for this technology.

Sulfuric Acid Alkylation of Isobutane by Olefins. Experience in Operation of a Jet Mixing Reactor

Experience in operating a sulfuric–acid alkylation jet reactor of new design — with no mixers and heat–exchange bank and a process scheme that includes this reactor, a hydrocyclone, three–phase separator, and circulating centrifugal pumps are described. An additional quantity of feedstock is added to the jet reactor operating in tandem with a cascade reactor without addition of circulating isobutane. The concentration of high–octane components in the products of the reaction, i.e., the alkylate production volume, increases. The results of operating the jet reactor in incorporation of propylene feedstock from the cascade reactor to “butylene” alkylate are reported. The additional volume of “propylene” alkylate is up to 1/3 of the total output of the unit, distillation is improved, and the Motor Octane Number decreases insignificantly — by a maximum of 0.5 points.

Sulfuric Acid Alkylation of Isobutane with Butylenes in a Continuous–Flow Tubular Contactor

The results of pilot–industrial tests of sulfuric acid alkylation of isobutene from butane–butylene fractions in a tubular continuous–flow contactor operating in the turbulent regime with internal cooling are reported. After the time of contact (≈30 sec) of the reagents, an alkylate that satisfies the requirements for specifications is formed. Data from the chromatographic–mass spectrometric analysis of the alkylate are reported.

Modernization of a sulfuric acid alkylation unit

One of the basic processes in production of the components of high-octane unleaded gasolines which satisfy contemporary environmental requirements is sulfuric acid alkylation of isobutane by butylenes. Increasing output and improving the quality of alkylate gasoline are greatly determined by the level of the technology and instrumentation of this process.

Operating experience with unit for sulfuric acid alkylation of isobutane by butylenes

The operation of units for the sulfuric acid alkylation of isobutanes by butylenes have been performed. The reaction was carried out in a KSG-3 horizontal sulfuric acid contractor. A butane-butylene fraction from catalytic cracking and an isobutane fraction from the central gas fractionating unit were used as a feedstock. The studies have shown that the unit will give a high-quality product under various conditions of operation. The specific consumption of sulfuric acid in processing different types of feed remains within acceptable limits.

New unit for sulfuric acid alkylation of isobutane by olefins

The authors describe and illustrate a sulfuric acid alkylation unit with a horizontal contact. As a result of the use of this design solution, the isobutane/olefin ratio is 10/1 in comparison with 4/1 to 5/1 in the other types of units, namely vertical reactors and cascade tank reactors. The unit was designed to process the butane-butylene cut (BBC) and part of the propane-propylene cut (PPC) from the G-43-107 cat cracker. The unit design includes provisions for controlled caustic washing of the feed and dehydration in an electric field. The authors present the basic data obtained in the three months of unit operation after startup, in comparison with the operating indexes of a sulfuric acid alkylation unit.

Purification of unsaturated gases contained in petroleum refining

The unsaturated gases obtained in processing petroleum cuts in catalytic and thermal crackers are used in the refinery mainly for the production of butane-butylene cut (BBC) with a content of organic sulfur compounds up to 0.02% by weight. This cut is used as feed to units for the sulfuric acid alkylation of isobutane. The propane-propy!ene cut (PPC) that is obtained at the same time, with a propylene content up to 50% by weight, has not yet found any effective applications, and it is used mainly (up to 85% of the resources) as domestic or industrial fuel. At the same time, the petrochemical industry is experiencing an acute shortage of propylene. The yield of PPC, relative to the total volume of unsaturated feed of the gas fractionation units (GFUs), is about 30%.

Variation of emulsion stability in sulfuric acid alkylation of isobutane with olefins

The makeup of the emulsion and its stability are determined to a great degree by the surface and viscosity properties of the acid. Investigates the dependence of emulsion stability on the properties of the acid circulating in the reactor section of an alkylation unit. Finds that as the surface-active substances that accumulate in the acid tend to lower its surface tension, and this in turn tends to disperse the hydrocarbon feedstock in the acid phase and forms a stable emulsion in the vigorously stirred reactor. Points out that as the acid viscosity increases, the segregation of microdrops of hydrocarbons from the acid phase becomes slower in the settling of the emulsion under natural conditions.

Utilization of spent butane-butylene fraction from methyl ethyl ketone production as feedstock for alkylate gasoline production

1. Feasibility has been demonstrated for use of a spent butane-butylene cut from MEK production in the sulfuric acid alkylation of isobutane with butylenes. The spent BBC can be used as sole feedstock or in mixture with a BBC obtained in catalytic and thermal cracking units. 2. The alkylate gasoline obtained when using spent BBC as the alkylation feedstock will meet the quality requirements of specification MRTU-38-1 -96-66.

Generalization of the experiences in the operation of industrial apparatuses for the sulfuric acid alkylation of isobutane with butylenes

1. Increasing the load of the apparatuses by making use of resources of C5 and C3 fractions is considered to be undesirable without significant reworking of the apparatuses; this increases the consumption of sulfuric acid. 2. The optimum conditions of the contact and fractionation blocks of the apparatus, predicted by the design, are to be rigidly held to, particularly with respect to the reaction temperature and the number of revolutions of the turbine. 3. The preliminary preparation of the raw material should be accomplished by means of mixing the butane-butylene fraction from thermal and catalytic cracking. 4. A scheme for the consecutive connection of the contact chambers (no less than three) should be put to use. 5. A propane colume for the depropanization of the isobutane recycle should be put into use. 6. The prospective reconstruction of apparatuses is suggested in order to bring about a further decrease in the sulfuric acid consumption and to improve other indexes in the operation of the apparatuses.