HF Alkylation Ensure Your Alkylation Unit Operates Reliably, with Minimum Corrosion, Low Acid Consumption, and on Spec Products
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8.7 Hydrofluoric Acid 8.7.1 General
8.7 Hydrofluoric Acid 8.7.1 General5-6 Hydrogen fluoride (HF) is listed as a Title III Hazardous Air Pollutant. Hydrogen fluoride is produced in 2 forms, as anhydrous hydrogen fluoride and as aqueous hydrofluoric acid. The predominant form manufactured is hydrogen fluoride, a colorless liquid or gas that fumes on contact with air and is water soluble. Traditionally, hydrofluoric acid has been used to etch and polish glass. Currently, the largest use for HF is in aluminum production. Other HF uses include uranium processing, petroleum alkylation, and stainless steel pickling. Hydrofluoric acid is also used to produce fluorocarbons used in aerosol sprays and in refrigerants. Although fluorocarbons are heavily regulated due to environmental concerns, other applications for fluorocarbons include manufacturing of resins, solvents, stain removers, surfactants, and pharmaceuticals. 8.7.2 Process Description1-3,6 Hydrofluoric acid is manufactured by the reaction of acid-grade fluorspar (CaF2) with sulfuric acid (H2SO4) as shown below: → CaF2 H2SO4 CaSO4 2HF A typical HF plant is shown schematically in Figure 8.7-1. The endothermic reaction requires 30 to 60 minutes in horizontal rotary kilns externally heated to 200 to 250°C (390 to 480°F). Dry fluorspar ("spar") and a slight excess of sulfuric acid are fed continuously to the front end of a stationary prereactor or directly to the kiln by a screw conveyor. The prereactor mixes the components prior to charging to the rotary kiln. Calcium sulfate (CaSO4) is removed through an air lock at the opposite end of the kiln. The gaseous reaction products—hydrogen fluoride and excess H2SO4 from the primary reaction and silicon tetrafluoride (SiF4), sulfur dioxide (SO2), carbon dioxide (CO2), and water produced in secondary reactions—are removed from the front end of the kiln along with entrained particulate. -
APPENDIX M SUMMARY of MAJOR TYPES of Carfg2 REFINERY
APPENDIX M SUMMARY OF MAJOR TYPES OF CaRFG2 REFINERY MODIFICATIONS Appendix M: Summan/ of Major Types of CaRFG2 Refinery Modifications: Alkylation Units A process unit that combines small-molecule hydrocarbon gases produced in the FCCU with a branched chain hydrocarbon called isobutane, producing a material called alkylate, which is blended into gasoline to raise the octane rating. Alkylate is a high octane, low vapor pressure gasoline blending component that essentially contains no olefins, aromatics, or sulfur. This plant improves the ultimate gasoline-making ability of the FCC plant. Therefore, many California refineries built new or modified existing units to increase alkylate production to blend and to produce greater amounts of CaRFG2. Alkylate is produced by combining C3, C4, and C5 components with isobutane (nC4). The process of alkylation is the reverse of cracking. Olefins (such as butenes and propenes) and isobutane are used as feedstocks and combined to produce alkylate. This process enables refiners to utilize lighter components that otherwise could not be blended into gasoline due to their high vapor pressures. Feed to alkylation unit can include pentanes from light cracked gasoline treaters, isobutanes from butane isomerization unit, and C3/C4 streams from delayed coking units. Isomerization Units - C4/C5/C6 A refinery that has an alkylation plant is not likely to have exactly enough is-butane to match the proplylene and butylene (olefin) feeds. The refiner usually has two choices - buy iso-butane or make it in a butane isomerization (Bl) plant. Isomerization is the rearrangement of straight chain hydrocarbon molecules to form branched chain products or to convert normal paraffins to their isomer. -
Is There an Acid Strong Enough to Dissolve Glass? – Superacids
ARTICLE Is there an acid strong enough to dissolve glass? – Superacids For anybody who watched cartoons growing up, the word unit is based on how acids behave in water, however as acid probably springs to mind images of gaping holes being very strong acids react extremely violently in water this burnt into the floor by a spill, and liquid that would dissolve scale cannot be used for the pure ‘common’ acids (nitric, anything you drop into it. The reality of the acids you hydrochloric and sulphuric) or anything stronger than them. encounter in schools, and most undergrad university Instead, a different unit, the Hammett acidity function (H0), courses is somewhat underwhelming – sure they will react is often preferred when discussing superacids. with chemicals, but, if handled safely, where’s the drama? A superacid can be defined as any compound with an People don’t realise that these extraordinarily strong acids acidity greater than 100% pure sulphuric acid, which has a do exist, they’re just rarely seen outside of research labs Hammett acidity function (H0) of −12 [1]. Modern definitions due to their extreme potency. These acids are capable of define a superacid as a medium in which the chemical dissolving almost anything – wax, rocks, metals (even potential of protons is higher than it is in pure sulphuric acid platinum), and yes, even glass. [2]. Considering that pure sulphuric acid is highly corrosive, you can be certain that anything more acidic than that is What are Superacids? going to be powerful. What are superacids? Its all in the name – super acids are intensely strong acids. -
[email protected] +1-703-527-3887 (International) Website
Date of Issue: 10 May 2016 SAFETY DATA SHEET 1. SUBSTANCE AND SOURCE IDENTIFICATION Product Identifier SRM Number: 3122 SRM Name: Hafnium (Hf) Standard Solution Other Means of Identification: Not applicable. Recommended Use of This Material and Restrictions of Use This Standard Reference Material (SRM) is intended for use as a primary calibration standard for the quantitative determination of hafnium. A unit of SRM 3122 consists of 50 mL of an acidified aqueous solution prepared gravimetrically to contain a known mass fraction of hafnium in a polyethylene bottle sealed in an aluminized bag. The solution contains volume fractions of nitric acid at approximately 1 % to 10 % and hydrofluoric acid at approximately 1 % to 2 %. Company Information National Institute of Standards and Technology Standard Reference Materials Program 100 Bureau Drive, Stop 2300 Gaithersburg, Maryland 20899-2300 Telephone: 301-975-2200 Emergency Telephone ChemTrec: FAX: 301-948-3730 1-800-424-9300 (North America) E-mail: [email protected] +1-703-527-3887 (International) Website: http://www.nist.gov/srm 2. HAZARDS IDENTIFICATION Classification Physical Hazard: Not classified. Health Hazard: Skin Corrosion/Irritation Category 1B Serious Eye Damage/Eye Irritation Category 1 Label Elements Symbol Signal Word DANGER Hazard Statement(s) H314 Causes severe skin burns and eye damage. Precautionary Statement(s) P260 Do not breathe fumes, mists, vapors, or spray. P264 Wash hands thoroughly after handling. P280 Wear protective gloves, protective clothing, and eye protection. P301+P330+P331 If swallowed: Rinse mouth. Do NOT induce vomiting. P303+P361+P353 If on skin (or hair): Remove immediately all contaminated clothing. Rinse skin with water. -
Olefins Recovery CRYO–PLUS ™ TECHNOLOGY 02
Olefins Recovery CRYO–PLUS ™ TECHNOLOGY 02 Refining & petrochemical experience. Linde Engineering North America Inc. (LENA) has constructed more than twenty (20) CRYO-PLUS™ units since 1984. Proprietary technology. Higher recovery with less energy. Refinery configuration. Designed to be used in low-pressure hydrogen-bearing Some of the principal crude oil conversion processes are off-gas applications, the patented CRYO-PLUS™ process fluid catalytic cracking and catalytic reforming. Both recovers approximately 98% of the propylene and heavier processes convert crude products (naphtha and gas oils) components with less energy required than traditional into high-octane unleaded gasoline blending components liquid recovery processes. (reformate and FCC gasoline). Cracking and reforming processes produce large quantities of both saturated and Higher product yields. unsaturated gases. The resulting incremental recovery of the olefins such as propylene and butylene by the CRYO-PLUS™ process means Excess fuel gas in refineries. that more feedstock is available for alkylation and polym- The additional gas that is produced overloads refinery erization. The result is an overall increase in production of gas recovery processes. As a result, large quantities of high-octane, zero sulfur, gasoline. propylene and propane (C3’s), and butylenes and butanes (C4’s) are being lost to the fuel system. Many refineries Our advanced design for ethylene recovery. produce more fuel gas than they use and flaring of the ™ The CRYO-PLUS C2= technology was specifically excess gas is all too frequently the result. designed to recover ethylene and heavier hydrocarbons from low-pressure hydrogen-bearing refinery off-gas streams. Our patented design has eliminated many of the problems associated with technologies that predate the CRYO-PLUS C2=™ technology. -
Reactions of Benzene & Its Derivatives
Organic Lecture Series ReactionsReactions ofof BenzeneBenzene && ItsIts DerivativesDerivatives Chapter 22 1 Organic Lecture Series Reactions of Benzene The most characteristic reaction of aromatic compounds is substitution at a ring carbon: Halogenation: FeCl3 H + Cl2 Cl + HCl Chlorobenzene Nitration: H2 SO4 HNO+ HNO3 2 + H2 O Nitrobenzene 2 Organic Lecture Series Reactions of Benzene Sulfonation: H 2 SO4 HSO+ SO3 3 H Benzenesulfonic acid Alkylation: AlX3 H + RX R + HX An alkylbenzene Acylation: O O AlX H + RCX 3 CR + HX An acylbenzene 3 Organic Lecture Series Carbon-Carbon Bond Formations: R RCl AlCl3 Arenes Alkylbenzenes 4 Organic Lecture Series Electrophilic Aromatic Substitution • Electrophilic aromatic substitution: a reaction in which a hydrogen atom of an aromatic ring is replaced by an electrophile H E + + + E + H • In this section: – several common types of electrophiles – how each is generated – the mechanism by which each replaces hydrogen 5 Organic Lecture Series EAS: General Mechanism • A general mechanism slow, rate + determining H Step 1: H + E+ E El e ctro - Resonance-stabilized phile cation intermediate + H fast Step 2: E + H+ E • Key question: What is the electrophile and how is it generated? 6 Organic Lecture Series + + 7 Organic Lecture Series Chlorination Step 1: formation of a chloronium ion Cl Cl + + - - Cl Cl+ Fe Cl Cl Cl Fe Cl Cl Fe Cl4 Cl Cl Chlorine Ferric chloride A molecular complex An ion pair (a Lewis (a Lewis with a positive charge containing a base) acid) on ch lorine ch loronium ion Step 2: attack of -
Providing a Guide
Lydia Miller, Emerson Automation Solutions, USA, explores how guided wave radar instruments can help a refinery make accurate level measurements in a corrosive environment. he alkylation process has long been an important The first two product streams come out of the main technique for refiners to create economical fractionator and are sent on for additional refinement. The gasoline blending components capable of raising propane is part of a mixed stream coming out of the acid the octane rating. There are two main process settler, also containing unrecovered HF and unreacted Tapproaches that are distinguished from one another by isobutane. This stream is sent to a de-propanising stage, their catalyst, either sulfuric acid or hydrofluoric acid (HF). which is effectively a large trayed distillation column, Both approaches take lighter components – primarily where propane is separated from the liquid and sent on for isobutane and olefins (various low-molecular-weight purification. The liquid stream is recycled back to the alkenes) – and, using one of the acids as a catalyst, convert original reactor and mixed with fresh feedstocks. The them to alkylate, which can be added to gasoline. highest possible degree of separation is desirable because This octane booster can be used year-round as it does when the propane is sold as a product it must not have HF not cause vapour pressure problems that are common to residues, and returning propane to the reactor reduces its alternative additives. Both processes were developed efficiency. during World War II to help increase the supply of high-octane aviation fuel available to allied air forces, and The de-propanising tower both have been in use ever since. -
2 Reactions Observed with Alkanes Do Not Occur with Aromatic Compounds 2 (SN2 Reactions Never Occur on Sp Hybridized Carbons!)
Reactions of Aromatic Compounds Aromatic compounds are stabilized by this “aromatic stabilization” energy Due to this stabilization, normal SN2 reactions observed with alkanes do not occur with aromatic compounds 2 (SN2 reactions never occur on sp hybridized carbons!) In addition, the double bonds of the aromatic group do not behave similar to alkene reactions Aromatic Substitution While aromatic compounds do not react through addition reactions seen earlier Br Br Br2 Br2 FeBr3 Br With an appropriate catalyst, benzene will react with bromine The product is a substitution, not an addition (the bromine has substituted for a hydrogen) The product is still aromatic Electrophilic Aromatic Substitution Aromatic compounds react through a unique substitution type reaction Initially an electrophile reacts with the aromatic compound to generate an arenium ion (also called sigma complex) The arenium ion has lost aromatic stabilization (one of the carbons of the ring no longer has a conjugated p orbital) Electrophilic Aromatic Substitution In a second step, the arenium ion loses a proton to regenerate the aromatic stabilization The product is thus a substitution (the electrophile has substituted for a hydrogen) and is called an Electrophilic Aromatic Substitution Energy Profile Transition states Transition states Intermediate Potential E energy H Starting material Products E Reaction Coordinate The rate-limiting step is therefore the formation of the arenium ion The properties of this arenium ion therefore control electrophilic aromatic substitutions (just like any reaction consider the stability of the intermediate formed in the rate limiting step) 1) The rate will be faster for anything that stabilizes the arenium ion 2) The regiochemistry will be controlled by the stability of the arenium ion The properties of the arenium ion will predict the outcome of electrophilic aromatic substitution chemistry Bromination To brominate an aromatic ring need to generate an electrophilic source of bromine In practice typically add a Lewis acid (e.g. -
Optimization of Refining Alkylation Process Unit Using Response
Optimization of Refining Alkylation Process Unit using Response Surface Methods By Jose Bird, Darryl Seillier, Michael Teders, and Grant Jacobson - Valero Energy Corporation Abstract This paper illustrates a methodology to optimize the operations of an alkylation unit based on response surface methods. Trial based process optimization requires the unit to be operated across a wide range of conditions. This approach tends to be opposed by refinery operations as it can disrupt the normal operations of a process unit. Using the methods presented in this paper, the general direction of process improvement is first identified using a first order profit response surface built from available operating data. The performance of the unit is then evaluated at the refinery by making systematic changes to the key factors in the projected direction of process improvement. The operating results are then used to build a localized second order profit response surface to generate a revised set of optimum targets. Multiple linear regression models are used to predict alkylate yield, alkylate octane and Iso-stripper or De-Isobutanizer reboiler duty as a function of key process variables. These models are then used to generate a profit response surface for selection of an optimum target region for step testing at the refinery prior to implementation of the unit targets. 1. Introduction An alkylation unit takes a feed stream with a high olefin content, typically originating from a fluid catalytic cracking (FCC) unit, and adds isobutane (IC4) which reacts with the olefins to produce a high octane alkylate product. Either hydrofluoric or sulfuric acid is used as a catalyst for the alkylation reaction. -
Alkylation of Aromatic Hydrocarbons with Divinylbenzene by Solid Polymeric Oxo Acids
Polymer Journal, Vol. 13, No.9, pp 915-917 (1981) NOTE Alkylation of Aromatic Hydrocarbons with Divinylbenzene by Solid Polymeric Oxo Acids Hiroshi HASEGAWA and Toshinobu HIGASHIMURA Department of Polymer Chemistry, Kyoto University, Kyoto 606, Japan. (Received February 28, 1981) KEY WORDS Solid Polymeric Oxo Acid I Alkylation I Bis(l-arylethyl)- benzene I Nafion-H I Amberlyst 151 Divinylbenzene I Aromatic Hydrocar bons I In our recent papers on the alkylation of aromatic hydrocarbons with styrene (eq 1),u we have shown that solid polymeric oxo acids as catalysts can bring about higher yields of 1-phenyl-1-arylethane (I) than the corresponding soluble oxo acids [e.g., poly(styrenesulfonic acid) (Amberlyst 15) vs. p CH3C6H4S03H; perfluorinated resinsulfonic acid (Nafion-H) vs. CF S0 H]. In view of the easy 3 3 yH3 yH3 separation of the product from the catalyst, the use (2) of these effective polymeric oxo acids should be H H industrially more advantageous than homogeneous (II) processes using soluble acidic catalysts. H H EXPERIMENTAL ) CH3-t-Ar + ift' CH2© ) Aromatic Hydrocarbons © Materials (I) (1) The DVB used in most experiments was an isomeric mixture (m-DVB/p-DVB = 70/30, purity;::: This article deals with the alkylation of aromatic 98%) separated from a commercial mixture of hydrocarbons (toluene and m-xylene) with divinyl DVB (60%) and ethylvinylbenzene (40%) by benzene (DVB) catalyzed by solid polymeric oxo preparative liquid chromatography.5 p-DVB and m acids (Nafion-H and Amberlyst 15). If the two vinyl DVB were isolated from the commercial mixture by groups in DVB, as in the case of styrene, react the method of Storey et a/. -
Modeling the HF Alkylation Chemistry Contents
think simulation | getting the chemistry right Modeling the HF alkylation chemistry An OLI Joint Industry Project (JIP) beginning April 2019 Contents Corrosion in the HF alkylation process ............................................................................................................ 2 Current modeling challenge ............................................................................................................................ 2 OLI Systems framework .................................................................................................................................. 2 Proposed Joint Industry Project (JIP) ............................................................................................................... 3 Project approach ............................................................................................................................................ 3 Project feasibility ............................................................................................................................................ 4 Pricing and deliverables ................................................................................................................................. 4 JIP details ....................................................................................................................................................... 5 Why choose OLI? .......................................................................................................................................... -
Alkylation: a Key to Cleaner Fuels and Better Vehicle Mileage
Alkylation A Key to Cleaner Gasoline & Better Vehicle Mileage American Fuel & Petrochemical Manufacturers (AFPM) is the leading trade association representing the majority of U.S. refining and petrochemical manufacturing capacity. Our members produce the fuels that power the U.S. economy and the chemical building blocks integral to millions of products that make modern life possible. U.S. gasoline needs alkylate for (OSHA) Process Safety Management and projects to transition from HF to Refineries that are close to chemical facil- its octane and environmental program and the Environmental even newer alkylation technologies are ities may have the option of selling their properties Protection Agency’s (EPA) Risk still in early phases. Eliminating the use propylene and butylene as feedstocks America’s fuel refiners use a chemical Management Program. But refineries that of either HF or sulfuric acid technology to manufacture plastics and sanitizers. process called alkylation to produce use HF go even further. Because nothing would severely diminish U.S. capacity to For refineries without this option, HF Refinery alkylation alkylate, a component of the cleaner is more important to the refining industry manufacture cleaner gasoline in line with alkylation technology provides an answer Alkylation is a refinery gasoline required by today’s higher- than the safety of our people and consumer demand. where sulfuric acid technology does not. is subject to layers process essential to the efficiency automobiles. Nearly 90 U.S. communities, facilities with HF alkylation HF units can co-process both propylene of regulation and refineries — representing 90% of total U.S. units also adhere to exacting industry and butylene to make alkylate.