Deactivation of hydroprocessing catalysts

Nitric acid production represents the largest source of N2O in the chemical industry, with a global annual emission of 400 kt N2O. The high impact of N2O on the environment as greenhouse gas and stratospheric ozone depletor, and the ongoing agreements and prospective regulations calls for the development of efficient and economical systems for N2O mitigation, but no mature commercial technology is yet available. In this review, the current state-of-the-art for N2O control in the nitric acid manufacture is presented. The formation of N2O and the process are analyzed and several options for reducing its emissions are discussed, depending on the position in the process. Primary abatement options deals with modifications in the ammonia oxidation catalyst, secondary abatement with options between the ammonia converter and the absorber, tertiary abatement with options in the tail-gas upstream of the expander, and quaternary abatement with options in the tail-gas downstream of the expander. The abatement technologies are evaluated based on the technical advantages and disadvantages, and cost efficiency.

Formation and control of N2O in nitric acid production: Where do we stand today?

Biofuels have grabbed the attention of engine researchers ever since the oil-crisis and escalating costs of petro-chemicals cropped up in the ׳70s. Ethanol and methanol were the most widely researched alcohols in IC engines. However, the last decade has witnessed significant amount of research in higher alcohols due to the development of modern fermentation processes using engineered micro-organisms that improved yield. Higher alcohols are attractive second/third generation biofuels that can be produced from sugary, starchy and ligno-cellulosic biomass feedstocks using sustainable pathways. The present work reviews the current literature concerning the effects of using higher alcohols ranging from 3-carbon propanol to 20-carbon phytol on combustion, performance and emission characteristics of a wide range of diesel engines under various test conditions. The literature is abound with evidence that higher alcohols reduce carcinogenic particulate emissions that are prevalent in diesel engines. NOx emissions either increased or decreased based on the domination of either cetane number or heat of evaporation. Brake specific fuel consumption (BSFC) of the engine usually suffered due to low energy content of alcohols. A notable feature is that the combination of higher alcohols (like butanol or pentanol), high exhaust gas recirculation (EGR) rates and late injection timing enabled low temperature combustion (LTC) in diesel engines that can simultaneously reduce smoke and NOx emissions with improved engine efficiency. It can be concluded that higher alcohols reduce smoke emissions with their fuel-borne oxygen; enhance air/fuel mixing by offering long ignition delay and eventually replace fossil diesel (partially or wholly) to enable a clean and efficient combustion in compression-ignition engines. The chief thrust areas include developing mutant strains with higher yield, higher tolerance to toxic inhibition and low-cost substrates for fermentation. Further work is required in stipulating optimum blend-fuel characteristics and ensuring the long-term durability of the engines using these fuels.

Use of higher alcohol biofuels in diesel engines: A review

The aim of this manuscript is to present an integrated process that includes reaction and separation steps for producing vanillin and lignin-based polyurethanes from Kraft lignin. It provides details about lignin oxidation and subsequent vanillin recovery, as well as, the synthesis of lignin-based polyurethanes. The oxidation of Kraft lignin in alkaline medium has been carried out in a batch reactor and the optimum operational conditions for vanillin production obtained. The feasibility of a continuous process for vanillin production has been analyzed using a structured bubble column reactor. The generated reaction stream (degraded lignin and sodium vanillate) was further subjected to an ultrafiltration process to recover the vanillate. An ion-exchange process allows recovering the vanillin by passing the vanillate solution through a column packed with an ion-exchange resin in H+ form. The remaining lignin can

An integrated process to produce vanillin and lignin-based polyurethanes from Kraft lignin

The catalytic reduction of carboxylic acid derivatives has witnessed a rapid development in recent years. These reactions, involving molecular hydrogen as the reducing agent, can be promoted by heterogeneous and homogeneous catalysts. The milestone achievements and recent results by both approaches are discussed in this Review. In particular, we focus on the mechanistic aspects of the catalytic hydrogenation and highlight the bifunctional nature of the mechanism that is preferred for supported metal catalysts as well as homogeneous transition metal complexes.

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Heterogeneous and homogeneous catalysis for the hydrogenation of carboxylic acid derivatives: history, advances and future directions

ACETOXYLATION Ethylene + Acetic Acid a Vinyl Acetate Butadiene + Acetic Acid a 1,4 Diacetoxy-2-Butene a 1,4 Butanediol a Tetrahydrofuran Propylene + Acetic Acid a Allyl Acetate a Allyl Alcohol ALKYLATION Introduction Alkylation of Benzene and Toluene Alkylation of Phenols Higher Alkylphenols Alkylation of Polynuclear Aromatics Alkylation of Aromatic Amines Transalkylation and Disproportionation Lower Aliphatic Amines by Alkylation of Ammonia (Amination) AMMONOLYSIS Phenol + Ammonia a Aniline Meta-Cresol + Ammonia a Meta-Toludine Diethylene Glycol + Ammonia a Morpholine AMMOXIDATION Propylene a Acrylonitrile Methane a HCN Isobutylene a Methacrylonitrile Aromatic Methyl Compounds a Nitriles CARBONYLATION Carboxylation of Olefins to Carboxylic Acids Carbon Monoxide + Chlorine a Phosgene DEHYDRATION OF ALCOHOLS 1-Phenylethanol a Styrene DEHYDROCHLORINATION C10 - C13 Chloridea Linear Olefins DEHYDROGENATION Dehydrogenation of Ethylbenzene Styrene Derivatives from Other Alkyl Aromatics Dehydrogenation of Lower Alkanes Alcohols to Aldehydes or Ketones Three Other Dehydrogenations EXPOXIDATION Ethylbenzene a Propylene Oxide + Styrene HYDRATION Ethylene a Ethanol Propylene a Isopropyl Alcohol N-ButenesaSec-Butanol Acrylonitrile a Alkylamide HYDROCHLORINATION Alkenes Alcohols HYDROGENATION General Background Hydrogenation of Aromatic Rings Hydrogenation of Heterocyclic Compounds Hydrogenation of Aliphatic Unsaturates Hydrogenation of Nitriles to Amines Hydrogenation of Nitroaromatics Hydrogenation of Haloaromatics Hydrogenation of Carbonyl Compounds Hydrogenation of Resins, Rosins, and Waxes Selective Hydrogenation of Fats and Oils Miscellaneous Hydrogenations HYDROGENOLYSIS Natural Fatty Acids and Fatty Esters a Fatty Alcohols Dimethylterephthalate a 1,4 Dimethylolcyclohexane Toluene a Benzene (Hydroalkylation) Methyl and Dimethyl Napthalene ISOMERIZATION Meta-Xylene a Para and Ortho-Xylene OXIDATION (INORGANIC) Sulfur Dioxide a Sulfur Trioxide a Sulfuric Acid Ammonia a Nitric Oxide a Nitrogen Dioxide a Nitric Acid Hydfrogen Sulfide a Sulfur OXIDATION (ORGANICS) General Ethylene a Ethylene Oxide Propene a Acrolein Propene a Acrolein a Acrylic Acid Butane or Benzene a Maleic Anhydride Ortho-Xylene or Naphthalene a Phthalic Anhydride Anthracene a Anthraquinone Methanol a Formaldehyde Isobutylene or Tert-Butyl Alcohol a Methacrolein a Methacrylic Acid OXYCHLORINATION Ethylene a 1,2 Dichloroethane a Vinyl Chloride PETROLEUM REFINING Catalytic Reforming Hydroprocessing (General) Hydrotreating Hydrocracking Isomerization Oligomerization (Polymer Gasoline Production) Fluid Catalytic Cracking Oxygenates SYNTHESIS GAS AND ITS PRODUCTS Historical Background Modern Synthesis Gas Production High and Low Temperature Shift Conversion (CO + H2O a H2 + CO2) Naphtha Steam Reforming Methanol Synthesis (Carbon Monoxide + Hydrogen a Methanol) Pure Carbon Monoxide from Synthesis Gas and Its Uses Pure Hydrogen from Synthesis Gases and Its Uses Ammonia Synthesis (Nitrogen + Hydrogen a Ammonia) Appendix

Handbook of Commercial Catalysts: Heterogeneous Catalysts

Chemical Reactor Design for Process Plants

Part 1 Theoretical and conceptual background: heterogenous catalysis and kinetics chemical equilibrium transport processes and the laws of conservation. Part 2 Design and operating models detailed recommendations on reactor design strategy shortcut procedures diagnosing reactor operating problems. Part 3 Examples: comparison of equilibrium-constant calculation methods generation of equilibrium-conversion and adiabatic-reaction temperature plots equilibrium composition for multiple reactions using free energy minimization design of reactors based on equilibrium approach highly exothermic reaction - comparison of reactor type use of a reactor model as an aid to catalyst selection - styrene production with radial-flow reactor use of reactor model in troubleshooting - catalytic reforming expert system for reactor diagnostics - steam reforming model development from recycle microreactor and pilot-plant data.

Howard F. Rase

Papers

Handbook of Commercial Catalysts: Heterogeneous Catalysts

Chemical Reactor Design for Process Plants

Fixed-Bed Reactor Design and Diagnostics: Gas-Phase Reactions

Project engineering of process plants

The philosophy and logic of chemical engineering