The catalytic conversion of light alkane feedstock is one of the promising industrial routes to prepare valuable chemical products: owing to its use in car and gas turbine engines, heaters, incinerators, and hydrocracking furnaces. Although the combustion of hydrocarbon fuels appears to be conceptually simple; the details of how alkane conversion to carbon dioxide and water occurs with concomitant release of energy, are enormously complex. Without timely and effective measures to mitigate the adverse impacts of greenhouse gases emission, the living environment of the world will continue to deteriorate and become increasingly unbearable. On that ground, the development of technological methods for methanol production via alkane conversion in a manner that is energy-conserving, inexpensive, environmentally-sustainable, and least-damaging to human health & welfare are of crucial importance. The applied method in this work contributes to these objectives.
It is well known that in the petroleum refining process, a substantial amount of C3–C4 fraction (existing as a mixture rather than individual component), is primarily recovered from crude oil distillation and by cracking of heavy molecules: bulk of which is flared as hydrocarbon fuel into the atmosphere through refinery furnace. On that ground, owing to the higher chemical reactivities of propane and butane, in comparison to methane, the use of C3–C4 hydrocarbon mixtures has been investigated as an alternative feedstock for methanol production, which apparently, to a large extent, is an important aspect of chemical technology and economics.
The present work evaluates the theoretical concepts, quantum chemical calculations, and experimental investigations to explore novel pathways for the direct oxidation of propane and butane fraction to methanol using a photochemical reactor.
To test the validity of the mechanism, the photochemical oxidation of C3–C4 gas fraction was investigated under three experimental phases under mild reaction conditions at a temperature (T = 100°C), at a pressure (P = 1 atm.), and at reaction times (tr) within 5 – 120mins (a) without exposure to irradiation, (b) with exposure to visible light irradiation at a wavelength region (λ = 420 nm), (c) with exposure to visible light irradiation at a wavelength region (λ = 420 nm) under the auto-catalytic influence of nitric acid vapor. The oxidation products obtained are methanol, as well as ethylene and propylene (very important star
Inhaltsverzeichnis (Table of Contents)
- INTRODUCTION
- Technical background
- Methanol synthesis: A brief history
- Production of methanol: From syn-gas, bio-sources, methyl formate, & CO2 recycling
- Methanol from biomass and cellulosic sources
- Methanol from chemical recycling of CO2
- Methanol from methyl formate
- Methanol from syn-gas
- Syn-gas preparation techniques
- Syn-gas via steam reforming
- Steam reforming of methane (SMR)
- Catalytic partial oxidation of methane (CPO)
- Auto-thermal reforming (ATR)
- CO2 reforming of methane
- Syn-gas from petroleum oil & higher hydrocarbons
- Syn-gas from coal
- Syn-gas via combined-reforming
- Syn-gas via heat-exchange reforming
- Methanol: Application & Economy
- Methanol as a chemical feedstock
- Methanol as transportation fuel
- Methanol as fuel in internal combustion engines (ICE)
- Methanol as fuel in compression ignition engines (DIESEL)
- Methanol as gasoline additive
- Methanol for static power & heat generation
- Methanol for waste-water denitrification
- Methanol for bio-diesel trans-esterification
- Market dynamics for methanol
- LITERATURE REVIEW
- Present-day investigations
- Main products of the DMTM process
- The ΔCH4/ΔO2 ratio
- The CH3OH/CH2O ratio
- The CO/CO2 ratio
- By-products of the DMTM process
- Yield of methanol & oxygenates
- Main parameters of the DMTM Process
- Effect of oxidant on the selectivity & yield of products
- Influence of oxygen concentration on the temperature and rate of reaction
- Effect of temperature on the yield of products
- Effect of pressure
- Effect of pressure on the temperature and rate of reaction
- Effect of pressure on the rate of branched-chain quasi-stationary reaction
- Effect of gas composition (3rd body effect)
- Heavier homologues of methane
- Inerts (N2, He)
- Carbon oxides (CO, CO2)
- Effect of homogeneous promoters
- Effect of heterogeneous catalysts
- Effect of catalyst’s surface area
- Effect of feed-flow rate (residence time)
- Surface-effect of reactor material
- Role of diffusion of reactants to the reactor surface
- Decomposition of products on the reactor surface
- Key features of the mechanism
- Mechanism for the gas-phase oxidation of methane in medium temperature range
- Main kinetic features of the DMTM process
- Role of heterogeneous process in the DMTM process
- The interplay between the homogeneous and the heterogeneous catalytic processes of methane oxidation
- Thermo-kinetic phenomena in partial oxidation of methane
- Experimentally-observed thermo-kinetic phenomena in the partial oxidation of methane
- Effect of physical promotion of the process
- Effect of the process under supercritical conditions
- Overview of experimental achievements on DMTM process
- Conclusions
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This work aims to explore novel pathways for the direct oxidation of propane and butane fraction to methanol using a photochemical reactor under mild reaction conditions. The main objective is to develop an environmentally-friendly, energy-efficient, and cost-effective method for methanol production from readily available hydrocarbon sources.
- Direct conversion of propane and butane fraction to methanol
- Photochemical activation of the reaction
- Auto-catalytic influence of nitric acid vapor
- Mild reaction conditions (low temperature and pressure)
- Environmental sustainability and energy efficiency
Zusammenfassung der Kapitel (Chapter Summaries)
- Chapter 1: Introduction: This chapter provides a comprehensive overview of methanol production methods, including conventional technologies, biomass-based synthesis, CO2 recycling, and methyl formate utilization. It also discusses the various applications of methanol, highlighting its importance as a chemical feedstock, transportation fuel, and power source.
- Chapter 2: Literature Review: This chapter examines previous research on the Direct Methane to Methanol (DMTM) process. It analyzes the influence of various parameters such as oxidants, temperature, pressure, gas composition, homogeneous promoters, heterogeneous catalysts, feed flow rate, and reactor materials on the yield and selectivity of methanol production. The chapter also discusses the complex mechanism of the DMTM process, including the role of free radical reactions and thermo-kinetic phenomena.
- Chapter 3: Justification and Objective of the Research Direction: This chapter presents the rationale for focusing on the direct conversion of propane and butane fraction to methanol. The chapter highlights the economic and environmental benefits of this approach, particularly regarding the utilization of readily available hydrocarbon sources and the development of a sustainable alternative to traditional methanol production methods.
- Chapter 4: Materials and Methods: This chapter details the experimental setup and procedures employed in the study, focusing on the photochemical reactor, the specific light source, and the analytical techniques used to identify and quantify reaction products.
- Chapter 5: Results and Discussion: This chapter presents the findings of the experimental investigation, focusing on the impact of nitric acid vapor on the direct conversion of propane-butane fraction to methanol under photochemical activation. The chapter also explores the mechanism of this process through theoretical calculations, including DFT and MCSCF-CI methods, to better understand the role of the excited nitrogen dioxide (NO2*) molecule in the reaction.
Schlüsselwörter (Keywords)
This research focuses on the direct conversion of propane and butane fraction to methanol using a photochemical reactor under mild reaction conditions. The key concepts explored include auto-catalysis, photo-activation, nitric acid vapor, hydroxyl radical, and the role of nitrogen dioxide (NO2) in promoting the reaction.
- Quote paper
- Ayodeji Ijagbuji (Author), 2015, The Eco-Friendly and Promoting Influence of Nitric Acid–Steam Vapors on the Oxidation of C3–C4 Parrafins into Methanol, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/288794
