Combustion Of Liquid Hydrocarbons Research Articles

Control of Liquid Hydrocarbon Combustion Parameters in Burners with Superheated Steam Supply

A numerical simulation of reacting mixture flow in a full-scale combustion chamber of a prototype burner with a fuel-sprayed jet of superheated steam and a controlled excess air ratio was performed based on a verified model. The influence of steam jets on the combustion parameters of the created prototype device was analyzed based on the results, and a comparison with data from various atmospheric burners, including evaporative and spray types, direct-flow and vortex types, and those with natural and forced (regulated) air supply, was made. Various schemes for supplying steam to burner devices were discussed. It was shown that the relative steam consumption is a parameter for controlling the emission of toxic combustion products, such as NOx and CO, for all designs. A high burner performance is achieved when superheated steam is supplied at more than 250 °C with a relative steam flow rate of >0.6. The design features of the burner systems and operational parameters that ensure high thermal and environmental efficiency when burning various types of fuel and waste are identified.

Low-Emission Waste-to-Energy Method of Liquid Fuel Combustion with a Mixture of Superheated Steam and Carbon Dioxide

Waste-to-energy approaches, aimed at using cheap energy carriers (oil production and refining waste, etc.), require the creation of new technologies with high energy efficiency and low emissions. One of the environmentally friendly methods is a superheated steam injection (SIM) into the combustion zone. At the same time, trends in CO2 reduction and recycling make carbon dioxide more attractive to use together with, or instead of, steam. This paper experimentally investigated the possibility of upgrading SIM to steam and the carbon dioxide injection method (SCIM) or the carbon dioxide injection method (CIM), where superheated steam and carbon dioxide are supplied together or completely replaced by CO2. In the example of diesel fuel, the characteristics of the combustion of liquid hydrocarbons in the presence of a mixture of superheated steam with CO2 in a spray burner are obtained and compared. It shows that a high completeness of fuel combustion is observed for all the studied modes. The analysis of combustion product composition demonstrates that when replacing the superheated steam with carbon dioxide, the levels of CO and NOx in the combustion products increase by 25%. All the investigated regimes comply with the EN:267 standard. The results obtained show that it is possible to realize SCIM and CIM approaches for waste-to-energy with the use of CO2.

Studying the benefits of liquid hydrocarbon combustion in a high-velocity jet of superheated steam when compared with other atomizers: CO2 and air

Studying the benefits of liquid hydrocarbon combustion in a high-velocity jet of superheated steam when compared with other atomizers: CO2 and air

Combustion of liquid hydrocarbons sprayed by air jet

In the present work, the combustion of liquid hydrocarbons sprayed by air jet was studied using diesel fuel as an example. The dependences of nitrogen oxides and carbon monoxide concentrations in combustion products on the fuel and air flow rates were investigated using an atmospheric burner device. It is shown that while diesel fuel sprayed by air jet there is a wider range of operating parameters in comparison with steam spraying due to the flameout. Compared with atomization by air jet at room temperature, steam and heated air spraying have advantages, for these regimes the NOx concentrations are observed to be lower.

Experimental Study of Combustion of Liquid Hydrocarbons under the Conditions of Steam Gasification in the Presence of a Diluent Gas

Experimental Study of Combustion of Liquid Hydrocarbons under the Conditions of Steam Gasification in the Presence of a Diluent Gas

Experimental study of liquid hydrocarbon combustion under conditions of steam gasification in the presence of diluent gas

This research is devoted to the study of the influence of diluent gas presence on liquid hydrocarbons combustion at the example of diesel fuel. Carbon dioxide was used as a diluent gas. Superheated steam was gradually replaced by carbon dioxide, which had the same temperature and delivery location, which allows performing a comparative analysis of the burner operation at different parameters of the atomizer (superheated steam, carbon dioxide, and their mixture). Temperature profiles measures along the flame symmetry axis and combustion products analysis were performed. The presence of carbon dioxide does not affect the temperature distribution at different modes. A higher diluent gas flow rate causes a slight increase in the NOx content in the flue gases.

Experimental Study of Combustion of Liquid Hydrocarbons under the Conditions of Vapor Gasification in the Presence of a Diluent Gas

Experimental Study of Combustion of Liquid Hydrocarbons under the Conditions of Vapor Gasification in the Presence of a Diluent Gas

Enhanced low-temperature stable combustion of hydrocarbon with suppressing the Leidenfrost effect

Low-temperature stable combustion of liquid hydrocarbons helps improve energy efficiency and alleviate environmental pollution. However, when hydrocarbons (mainly saturated ones) are used as aircraft fuel, they show a long ignition delay time (IDT) and high ignition temperature as a result of Leidenfrost effect and chemical inertness of the CH bond. In especial, the insulated fuel vapor film due to the Leidenfrost effect that inhibits the heat transfer efficiency in the wide Leidenfrost region is unfavorable. Herein, we first propose a strategy that combines low-temperature self-oxidation and enhanced heat conduction to achieve low-temperature stable combustion of hydrocarbon while suppressing the Leidenfrost effect. Specifically, moderately reactive organometallic compound methoxydiethylborane (MDEB) with special radicals and silver nanoparticles (Ag NPs) with high thermal conductivity are preferred as fuel modifiers. By thermodynamic calculation, the heat released by the self-oxidation of MDEB is two orders of magnitude higher than the evaporation latent heat of n-decane, suggesting the applicability of energy conversion supported by enhancing fuel reactivity in suppressing the Leidenfrost effect. Ignition experiment results show that the negative temperature dependence associated with the Leidenfrost effect is eliminated under the specific fuel composition. Encouragingly, compared with n-decane, the IDT of MDEB/Ag/n-decane hybrid fuel is reduced from 4027 to ∼10 ms at a surface temperature of 600 °C. Comparing the ignition of MDEB/Ag/n-decane and MDEB/n-decane hybrid fuels at same temperatures, the influence of Ag NPs on IDT is highlighted by its significant decrease (∼28%). The minimum ignition temperature of n-decane-based hybrid fuel decreases to 112 °C, which is 508 °C lower than that of n-decane. These two ignition characteristic values are the low limit of saturated hydrocarbons to date. Our results thus provide a promising tool for enhancing the low-temperature ignition reliability and combustion stability of liquid hydrocarbons, which potentially decreases the pollution from the low temperature combustion.

Investigation of high speed steam jet effect on combustion of substandard liquid hydrocarbons

Combustion of liquid hydrocarbon fuel dispersed by superheated steam jet was experimentally studied. Characteristics of the combustion process (heat release, emission of toxic products, flame temperature) were investigated in a laboratory direct-flow atmospheric burner (capacity up to 20 kW) at different operating systems with waste transmission automotive oil as fuel example. Regimes were found which provoke stable combustion of non-quality liquid hydrocarbons. It was shown dependences of heat, flue gas parameters on superheated steam flow rates, fuel flow rates, flame temperatures.

Evolution of the soot particle size distribution along the centreline of an n-heptane/toluene co-flow diffusion flame

A newly developed experimental set-up for studying liquid hydrocarbon combustion in the well-established Yale burner was used to investigate the correlation between fuel composition and its sooting propensity. Soot particle size distributions (PSDs) and flame temperatures along the centreline of an n-heptane/toluene co-flow diffusion flame are reported. The results are compared to soot temperature and volume fraction profiles obtained using colour ratio pyrometry. The addition of toluene (0, 5, 10, and 15 mol%) to heptane moved soot inception to lower heights above the burner (HAB). The earlier inception extended the soot growth zone in the toluene-laden flames, leading to larger soot primary and agglomerate particles. Toluene addition had little influence on the maximum soot number density, indicating that the observed increase in soot volume fraction can mainly be attributed to the increase in particle size. The reported PSDs inside a vapour-fed diffusion flame are the first of their kind and provide a comprehensive dataset for future studies of combustion chemistry and soot particle models.

Combustion of Substandard Liquid Hydrocarbons in Atmosphere Burners with Steam Gasification

In this research we experimentally investigated the process of liquid hydrocarbon combustion at spraying by a jet of superheated steam, using waste automobile transmission oil as an example. In the laboratory burner model (up to 20 kW) we studied the effect of mode parameters on the characteristics of the combustion process in the presence of superheated steam, namely, heat release and composition of combustion products, and flame temperature. The possibility of combustion of substandard liquid hydrocarbons in a straight-flow atmospheric burner at 10 kW is shown. Dependences of the main thermotechnical and environmental characteristics of the burner on temperature and flow rate of superheated steam and fuel consumption are found. The fuel combustion efficiency reaches 97%, observing minimal concentrations of toxic combustion products: {CO} = 20 mg/kWh{NO}x = 60 mg/kWh, which corresponds to class 3 of EN 267.

Diesel fuel combustion in a direct-flow evaporative burner with superheated steam supply

A method of liquid hydrocarbon combustion in a new evaporative burner with a controlled forced supply of superheated steam jet into the reaction zone was experimentally studied in this paper using diesel fuel. For the first time, dependences of the flame temperature and thermal and environmental characteristics on the steam flow rate and overheating were obtained. The boundaries of characteristic combustion regimes were determined. During fuel combustion in a superheated steam jet, the concentrations of nitrogen oxide and carbon monoxide in the combustion products are significantly lower than the maximum permissible concentrations established for this type of burner device, according to EN 267: 0–5 ppm for CO and 25–50 ppm for NOx. The relative steam mass flow rate, in contrast to the steam temperature, substantially influences the main characteristics of the combustion process. Maximum heat release 45 MJ/kg is achieved in a system in which the steam mass flow rate equals half of the fuel mass flow rate. The new combustion method ensures high-energy efficiency and environmental safety and may be used in the development of technologies for the disposal of nonstandard liquid hydrocarbon fuels and industrial wastes with simultaneous heat energy production.

Combustion of liquid hydrocarbons in a jet of superheated steam

The process of combustion of liquid hydrocarbons with spraying by a jet of superheated steam in a direct-flow burner is studied experimentally in this work at the example of diesel fuel. The aim of research is to study the effect of regime parameters (steam and fuel flow rate) on the main characteristics of the process. Specific amount of heat and useful thermal power were determined from the measurements on a flow calorimeter, a gas analyzer Testo 350 was used to perform the gas analysis of combustion products. A regime map was plotted and results of characteristic combustion conditions were presented. The regimes of high completeness of fuel combustion with low production of toxic combustion products were determined.

Diesel fuel combustion by spraying in a superheated steam jet

This paper experimentally studies the process of liquid hydrocarbon combustion by spraying a jet of superheated steam using diesel fuel as an example. A laboratory burner sample (with a power of up to 20 kW) is used to assess the effect of the operating parameters on the characteristics of the combustion process in the presence of superheated steam: heat generation, the composition of the combustion, products and the flame temperature. The dependences of the main calorific and environmental indicators of the burner on the temperature and flow rates of superheated steam and fuel are found. The maximal completeness of fuel combustion reaches 98.6%. With an increase in the mass fraction of the steam (up to 50%), a decrease in the content of nitrogen oxides is observed. The minimal contents of carbon monoxide are CO = 5 mg/kWh, while the level of nitrogen oxides is maximal but does not exceed 90 mg/kWh, corresponding to class 3 by EN 267. Compared with heated air jet technology, steam gasification technology has significant environmental advantages. The results are in demand for scientific substantiation of energy efficient and environmentally friendly ways of utilising substandard liquid hydrocarbons with heat production, verification of the mathematical model, and numerical simulation of the process. The results can be used for the development of the energy efficient and environmentally friendly technologies of liquid hydrocarbon waste utilisation with the production of heat energy.

Influence of parameters of superheated steam on combustion of liquid hydrocarbons

The main characteristics of liquid hydrocarbon combustion in a jet of superheated steam were studied. The influence of main physical parameters of steam flow on combustion parameters (temperature distribution in flame, generated heat power, combustion products composition) were measured for the original burner apparatus.

A flow blurring nozzle design for combustion in a closed system

The objective of this research is to design an atomizer for liquid hydrocarbon combustion in meso-scale applications. The goal is to use the atomizer in a closed meso-scale combustion chamber. For these applications, the heat output desired is between 1 and 4 kW (2–8 ml/min of gasoline). This heat will ultimately be used to power a meso scale energy conversion device. A high pressure atomizer, such as the fuel injectors used in automotive engines do not function well at the low fuel flow rates required here. Instead, this research is focused on a new nozzle design based on a relatively new phenomena called flow blurring. Flow blurring is defined as the generation of small turbulence scales in a liquid from a singular back-flow pattern of a gas. It has a high vaporization efficiency, operates within a wide flow rate range and is inexpensive. There are a few studies of atomizers based on the flow blurring phenomena. These studies only consider an original flow blurring nozzle with a single air supply. However, at the target flow rate, the standard flow blurring nozzle cannot be used since the exit velocity will be much higher than the flame speed. Thus, sustainable combustion is not possible. To solve the problem, a new dual air supply nozzle with diffuser is proposed. A design framework and experimental results of the proposed nozzle are presented. The experimental data demonstrate that the proposed nozzle greatly improves combustion stability over the original nozzle and can achieve clean and stable combustion for a wide range of fuel flow rates. This new design of a flow blurring nozzle can also be applied to other potential applications requiring small droplets at low flow rates.

Investigation of soot nanoparticles during combustion of liquid hydrocarbons with injection of a superheated steam jet into the reaction zone

The characteristics of soot particles formed during combustion of liquid hydrocarbons in a laboratory model of an original burner with injection of a superheated steam jet into the reaction zone are experimentally studied. The concentration and size distribution of soot particles formed in the burner flame are measured by a diffusion aerosol spectrometer. It is shown that the majority of the primary particles have sizes ranging from 20 to 60 nm. The particle concentration in the external flame rapidly decreases with distance from the burner exit from 108 to 5 · 106 cm−3. The images obtained by transmission electron microscopy demonstrate a chain-branched (fractallike) structure of aggregates. The primary particles composing these aggregates have a union-like structure with the interplane distance between the layers smaller than 1 nm. Compact aggregates with sizes up to 500 nm are observed in cooled combustion products. The content of soot in combustion products is 35 mg/m3, and the mean particle mass is 7 · 10−12 mg. Results obtained in the combustion modes with injection of a superheated steam jet and with injection of an air jet are compared.

Modeling hydrodynamic flows in plasma fluxes when depositing metal layer on the surface of catalyst converters

Air pollution with harmful substances resulting from combustion of liquid hydrocarbons and emitted into atmosphere became one of the global environmental problems in the late 20th century. The systems of neutralization capable to reduce toxicity of exhaust gases several times are very important for making environmentally safer combustion products discharged into the atmosphere. As revealed in the literature review, one of the most promising purification procedures is neutralization of burnt gases by catalyst converter systems. The principal working element in the converter is a catalytic layer of metals deposited on ceramics, with thickness 20-60 micron and a well-developed micro-relief. The paper presents a thoroughly substantiated new procedure of deposing a nano-scale surface layer of metal-catalyst particles, furthering the utilization of catalysts on a new level. The paper provides description of mathematical models and computational researches into plasma fluxes under high-frequency impulse input delivered to electrode material, explorations of developing Kelvin-Helmholtz, Marangoni and magnetic hydrodynamic instabilities on the surface of liquid electrode metal droplet in the nano-scale range of wavelengths to obtain a flow of nano-meter particles of cathode material. The authors have outlined a physical and mathematical model of magnetic and hydrodynamic instability for the case of melt flowing on the boundary with the molten metal with the purpose to predict the interphase shape and mutual effect of formed plasma jet and liquid metal droplet on the electrode in the nano-scale range of wavelengths at high-frequency impact on the boundary “electrode-liquid layer”.

Investigation of Soot Nanoparticles during Combustion of Liquid Hydrocarbons with Injection of a Superheated Steam Jet into the Combustion Region

Investigation of Soot Nanoparticles during Combustion of Liquid Hydrocarbons with Injection of a Superheated Steam Jet into the Combustion Region

Steam-enhanced regime for liquid hydrocarbons combustion: velocity distribution in the burner flame

The lab-scale burner device with proprietary design was used for combustion of diesel fuel in a steam-enhanced regime. This operation mode ensures drastic intensification of liquid hydrocarbon combustion due to supply of superheated steam jet to the combustion zone. The particle image velocimetry technique was used for study of velocity field in the burner flame. The method of seeding of flow zone with new kind of tracers (micro-sized silica particles produced from silicon oil added to liquid fuel) was tested.