This is the third edition of chemical reactor analysis and design. Two hydrofluoric acid hf alkylation processes are commonly available. Us7652181b1 alkylation reactor design with effluent recycle. Some equipment dedicated to hf regeneration or removal. Hydrogen fluoride gas 4000 gramton alkylate alkyclean solid acid solid design parameters and reliable scaleup demonstration unit. Invistigation on alkylation process sust repository. Yield and octane number of the product from hf alkylation process. The abb process fourier transform infrared ftir analyzer for hf.
The complexity of the hf alkylation process has bee n illustrated in this document. Conversion basics sulphuric acid alkylation reactions are typically optimised at a reaction temperature of 45. Alkylation the addition of an alkyl group to any compound is an alkylation reaction but in petroleum refining terminology the term alkylation is used for the reaction of low molecular weight olefins with an isoparaffin to form higher molecular. Corrosion from this water rich hf is a problem for this process. A phillips design alternative demonstrated that the density difference.
The predominant form manufactured is hydrogen fluoride, a colorless liquid or gas that fumes on contact with air and is. Concentrated hydrofluoric acid hf is then mixed in and fed to the reactor. Alkylation consumes only about 3% of the total h 2 so 4 production, and h 2 so 4 alkylation plants are less strictly regulated than hf plants. The alkyclean process employs a zeolite catalyst coupled with a n. Process simulation predicts corrosive conditions in hf. Norton engineering has a wide range of experience working with both sulfuric acid and hydrofluoric acid hf alkylation units.
The paper discusses background, hf alkylation, hasoa alkylation, solidacid catalysts, reaction mechanism, activity and selectivity, feedstock effects, catalyst life, resistance to poisons. Alkylation process petroleum refining pdf squarespace. An alky unit uses sulfuric or hydrofluoric acid as the catalyst to react to unsaturated hydrocarbons with. In a different alkylating process, solid zeolite is used as the catalyst. Alkyclean solid acid catalyst alkylation technology. Closed open dib tower light ends separation alkylation reactor no.
In an alkylation unit, the reactant gases are pressurized, liquefied and mixed with an acid catalyst, which is either hf or h 2 so 4. Exelus has developed an innovative isoparaffin alkylation technology exsact, as an economically viable alternative to hf h2so4 processes. Shuiqiang duan, mengzijing chen, rui zhang, xianghai meng, jian xu, wei du, zhenbo wang, zhichang liu. Pep00 rn abstract process economics program report 88b alkylation for motor fuels june 2001 the catalytic addition reaction of isobutane with light olefins to form highly branched. Modeling the multistage process of the linear alkylbenzene. One of the frequently employed alkylation reactions is the friedelcrafts. Recycle benzene enters the hf alkylation reactor 10 through a line 26. Effect of light phase inlet structure on liquidliquid cyclone reactor for isobutane alkylation catalyzed by ionic liquid. Inherently safer than liquid acid technologies, particularly hf. Chemical engineering research and design 2019, 147, 510519. For batch reactors, conversion is a function of time whereas for. An alkylation unit alky is one of the conversion processes used in petroleum refineries. Sep 09, 2016 commercial development sulfuric acid and solid acid, it is expected that the fractionation system of a hf alkylation unit can be reused, based on the lower required isobutane to olefin ratio required with sulfuric acid or solid acid alkylation compared to hf alkylation. The main difference for the alkyclean process is the use of multiple fixedbed reactors operating in cyclical mode, which permits continuous operation while one reactor is being.
The second conversion option using a novel reactor design is also suitable for both gravityflow and pumpedflow hf alkylation units. The importance of the hf alkylation process in a refinery has gained greater importance because. Control valve guidelines hydrofluoric acid applications 12. Pdf troubleshooting hf alkylation units edwin aguilar. Providing a guide hydrocarbon engineering april 2018 emerson. Hf alkylation process description olefins c3c4 from the fcc unit are combined with isobutane ic4 and are first treated with a mol sieve bed to remove water. A novel fixedbed reactor that is designed to enhance the performance of this. Petroleum refining design and applications handbook. Jan 09, 2021 the process design of the demo reactor section has been set to achieve operating conditions and compositional profiles analogous to those for a commercial design. Hydrofluoric acid in us refineries mazzocchi united.
This book is the most uptodate and comprehensive coverage of the most significant and recent changes to petroleum refining, presenting the stateoftheart to the engineer, scientist, or student. The alkylation process combines light isoparaffins, most commonly isobutane, with c 3 c 4 olefins, to produce a mixture of higher molecular weight isoparaffins i. The reactor effluent flows to a settler, where the acid phase separates from the hydrocarbon phase. Hydrofluoric acid alkylation conversion and expansion. The effect of operating conditions on corrosion in hf alkylation units.
The first was published by wiley in 1979 and the second, after a substantial revision, in 1990. Cdalky breaks the lowtemperature barrier through innovative reactor design. In some cases, the performance model may include a pilot plant or other facility for predicting plant performance and collecting the necessary design data. Raw material benzene and 1dodecene enter to the reactor in the liquid phase. Hydrofluoric acid alkylation hfu unit optimization the use. Chemical reactor analysis and design, 3rd edition silo. Jul 01, 2019 thus, the amount of har formed in the alkylation reactor at a given activity of the hf catalyst, and therefore the optimal acid flow rate to regeneration, is determined by the amount of dienes formed in the dehydrogenation reactor and depends on the aromatics content in feedstock. Alkylation is the process of adding alkyl groups to a substrate molecule and has importance in a variety of applications. The alkylation reaction takes place combining the olefins with the isobutane to. The hf processes have no mechanical stirring as in the sulphuric acid processes. Alkingation unit news newspapers books scholar jstor august 2019.
An olefincontaining stream, which typically contains paraffins also, enters hf alkylation reactor 10 through a line 12. Solidacid alkylation process development is at crucial stage. Alkylation reactions are catalyzed by liquid and solid acids hf alkylation and sulfuric acid. The process combines an unsaturated light hydrocarbon with isobutane to produce alkylate. Hf alkylation in promax pengrobinson polar thermodynamics tuned to predict. Optimization of refining alkylation process unit using.
Pdf introductionbasis of design industrial processes for isobutane. This method, pioneered by connoco phillips in the 1990s, yields a highly reliable precalibration for the abb hf alkylation analyzer, which is always supplied fully. Alkylation reactor effluent splitting layout in slovnaft refinery. Chemical reaction engineering is the synthesis of all these factors with the aim of. It is used to convert isobutane and lowmolecularweight alkenes primarily a mixture of propene and butene into alkylate, a high octane gasoline component. The mixture is fed to the reactor, where it is highly. Process key cyclic reactor operation short cycle alkylation mild regeneration alternating periods of alkylation and liquid phase mild regeneration with ic 4 and dissolved h 2 seamless no change in operating conditions. Effluent from reactor 50 is removed via line 14 and charged to separator 60.
In covering these topics, the tutorial will draw upon the combined previous. Us5098668a hf alkylation unit with acid evacuation. The demo reactors are sufficiently large and proportioned to allow for reliable scaleup. Present and future alkylation processes in refineries. It is a lower cost, yet robust design option for hf conversion. The particular design of the reactor is not a part of my invention, and the design of such reactors is well known to those skilled in the hf alkylation arts. In organic chemistry, alkylation reactions are common. For alkylations with hf as the catalyst, isobutane consumptions are often 6. Energy information administration in practice only isobutane is used because isopentane has a sufficiently. The low viscosity of hf and the high solubility of isobutane in the acid allow for a simpler design. Figure 1 is a typical process flow diagram of a hydrofluoric hf acid alkylation unit. Pdf application of hazop, lopa and sil to an alkylation. The existing hf acid settler is converted to a sulphuric acid alkylation reactor utilising common refinery equipment with no moving parts within the converted acid settler. Pump and mechanical seal a pplication and design considerations for increased reliability.
Us5098668a hf alkylation unit with acid evacuation system. The hf catalyst can become rich, that is, it can contain water. Advances in hf acid alkylation conversion and expansion. Olefins and isobutane are dried and fed to a reactor, where the alkylation reaction takes place over the hf catalyst. Recent information clarifying the dangers of hf is causing refineries that use hf to reconsider the catalyst, or. Revamp of hf alkylation unit employs solidacid catalyst. Our experienced engineers are familiar with the unique challenges and dangers that an alkylation unit presents. Structurereactorseparationrecycle massbalance equationsselection of a robust. The reactor effluent flows to a settler, where the acid phase separates from. In searching for the optimum it is not just the cost of the reactor that must be minimized. Figure below shows a process schematic for hydrofluoric acid hf alkylation. The design uses reactor effluent recycle to reduce the difference in temperature across the reaction zone improving selectivity and insuring the maintenance of a liquid phase in the reactor. Structurereactor separationrecycle massbalance equationsselection of a robust. Us7652181b1 alkylation reactor design with effluent.
Hydrogen fluoride hf is listed as a title iii hazardous air pollutant. Water rich hf corrosion is associated with the phase changes of the process. Our experienced engineers are familiar with the unique challenges and dangers that an alkylation. Design of the reactor is no routine matter, and many alternatives can be proposed for a process. Atps 2018 hf acid alkylation tutorial pump and seal. Alkylation technology study south coast air quality management.
For the conversion of a gravityflow hf alkylation unit, the existing vertical acid settler will be retrofitted with proprietary internals for mixing and will perform the function of an alkylation reactor, acid settler. Today, the cumene is used almost exclusively for manufacturing phenol and acetone. Olefin and isobutane feed streams are dried to remove water before they are mixed with the isobutane recycle stream. Revamping an hf alkylation unit to use a solidacid catalyst is a costeffective means to comply with new inherently safer technology legislation, restart an hf unit idled after an accident or. Solidacid alkylation process development is at crucial. The mixture is fed to the reactor, where it is highly dispersed into an incoming stream of acid catalyst. Jul 16, 2015 hf alkylation and sulfuric acid alkylation are the most widely practiced commercial motor fuel alkylation processes and are the focus of this section. The hf process only creates a small amount of organofluorine side products which are continuously removed from the reactor and the consumed hf is replenished. Design and operational features the general process scheme, isobutane circulation rates and other conditions are similar to those of liquid acid alkylation processes. The typical hydrofluoric acid hf alkylation unit requires far less acid than a sulfuric acid unit to achieve the same volume of alkylate. Isoalky technology is commercially viable alternative. Alkylate is a premium gasoline blending component alkylation capacity steadily increased annually since 1980s due to gasoline specifications high octane number isooctane 100 low vapor pressure less volatile. H2so4 hf reaction mechanism ionization mechanism to intermediate stage.
For the conversion of a gravityflow hf alkylation unit, the existing vertical acid settler will be retrofitted with proprietary internals for mixing and will perform the function of an alkylation reactor, acid. In this reaction, the presence of a lewis acid catalyst such as alcl 3, an alkyl halide, and an aryl compound form a substituted aromatic ring. The hf alkylation process uses hydrofluoric acid which is dangerous and requires special treatment, particularly in the area of shaft sealing along with. The alkylation reaction takes place combining the olefins with the isobutane to form the alkylate product which consists of high octane value products that are later blended into the gasoline pool. Isoalky process vs hf and sulfuric alkylation h 2 so 4 hf isoalky temperature, f 60 95 95 pressure, psig 60 200 reactor 50% 50 80% 5% ext. Pdf preliminar concept of a reaction system for alkylation. Alkylation the addition of an alkyl group to any compound is an alkylation reaction but in petroleum refining terminology the term alkylation is used for the reaction of low molecular weight olefins with an isoparaffin to form.
This included sample system design, metallurgy considerations and model development. The reactions taking place in the alkylation reactor are many and relatively complex, p. This book contains significant information on corrosion and the effects of operating. Hydrofluoric acid alkylation refinery process unit optimization, jointly developed with.
The unit also has an acid evacuation system which is capable of transferring the acid from the reactor section of the unit to the receiver within a very short period of time in the event of an. Handbook of petroleum refining processes, fourth edition. Hf alkylation process with addition of acid regenarator. The reactions taking place in the alkylation reactor are many and relatively complex, proceeding by a. Isobutane and c 3 c 4 olefins are produced as byproducts from fcc and other catalytic and thermal conversion processes in a refinery. One design may have low reactor cost, but the materials leaving the unit may be such that their treatment requires a much higher cost than alternative designs. Upflow reactor ufr technologies for fixedbed residuum. Fillings raschig rings have been backfilled on the catalyst layer a 64 mm high 17 and under the catalyst layer 6 mm high 16. An improved alkylation reactor design is disclosed. Alkylation and polymerization process alkene gasoline. The minimum design capacity may be,estimated from similar plant that. A unique solidacid catalyst that converts light hydrocarbons into alkylates and 2.
An hf alkylation unit with improved safety features including an acid storage and evacuation receiver which maintains a large proportion of the acid inventory of the unit at a remote, safe location. Alkylation expertise increase octane while reducing your operating costs. Two years of testing and development followed on hf alkylation pilot scale units. Corrosion and fouling in hf alkylation units are closely linked to feed quality and. It does, however, use hf, which is both highly toxic and corrosive. Hydrogen fluoride is produced in 2 forms, as anhydrous hydrogen fluoride and as aqueous hydrofluoric acid. Jan 29, 2015 motor fuel alkylation in the petroleum refining industry refers to the acidcatalyzed conversion of c 3c 5 olefins with isobutane into highly branched c5c12 isoparaffins collectively called alkylate, a valuable gasoline blending component. Simple flowsheet for modified hf alkylation technology. The process occurs in the presence of an acid such as sulfuric acid h 2 so 4 or hydrofluoric acid hf as catalyst. The hf alkylation process uses hydrofluoric acid which is dangerous and requires special treatment, particularly in the area of shaft sealing along with pump design and construction. The predominant form manufactured is hydrogen fluoride, a colorless liquid or gas that fumes on contact with air and is water soluble.
Effect of light phase inlet structure on liquidliquid cyclone reactor for isobutane alkylation. Generally hf alkylation requires the use of a globe. In recent years, considerable development effort has gone into solid acid catalysts and processes that mitigate the hazards associated with hf and h2so4. Acid is sulphuric acid h2so4 or fluorohydroric acid hf. Instead, the design engineer builds a mathematical model of the process, usually in the form of computer simulations of the process, reactors, and other key equipment. Shutting down a sulfuric acid alkylation unit reactor. An hf alkylation unit is fairly complex figure 1, but the process does not require particularly high temperatures nor high pressures. Development of a alkyclean solid acid catalyst solid acid. However, in the last five years, more h2s04 than hf type units have been built due to environmental and safety concerns. Hydrofluoric acid, used in older plants 8, is ruled out as the catalyst due to safety and. Determination of hydrodynamic regime of the reactor.
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