Lot's of information to digest then my comments in a separate post later today, got some chores to do first.
OK here we go:
Rob
https://en.wikipedia.org/wiki/FuelFuels are any materials that store potential energy in forms that can be practicably released and used as heat energy. The concept originally applied solely to those materials storing energy in the form of chemical energy that could be released through combustion,[1] but the concept has since been also applied to other sources of heat energy such as nuclear energy (via nuclear fission or nuclear fusion), as well as releases of chemical energy released through non-combustion oxidation (such as in cellular biology or in fuel cells).
The heat energy released by many fuels is harnessed into mechanical energy via an engine. Other times the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that comes with combustion. Fuels are also used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release un-usable energy. Hydrocarbons are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are also utilized.
Fuels are contrasted with other methods of storing potential energy, such as those that directly release electrical energy (such as batteries and capacitors) or mechanical energy (such as flywheels, springs, compressed air, or water in a reservoir).
https://en.wikipedia.org/wiki/Hydrogen_fuelEnergy
Once manufactured, hydrogen is an energy carrier (i.e. a store for energy first generated by other means). The energy is eventually delivered as heat when the hydrogen is burned. The heat in a hydrogen flame is a radiant emission from the newly formed water molecules. The water molecules are in an excited state on initial formation and then transition to a ground state; the transition unleashing thermal radiation. When burning in air, the temperature is roughly 2000°C.
https://en.wikipedia.org/wiki/OxyhydrogenOxyhydrogen is a mixture of hydrogen (H2) and oxygen (O2) gases. This gaseous mixture is used for torches for the processing of refractory materials and was the first[1] gaseous mixture used for welding. Theoretically, a ratio of 2:1 hydrogen:oxygen is enough to achieve maximum efficiency; in practice a ratio 4:1 or 5:1 is required to avoid an oxidizing flame.[2]
This mixture may sometimes be called by an old term knallgas (German; "bang-gas"), although some authors used to define knallgas to be a generic term for the mixture of fuel with precise amount of oxygen required for complete combustion, thus 2:1 oxyhydrogen would be called "hydrogen-knallgas".[3]
Brown's gas[4] and HHO are fringe science terms for a 2:1 mixture of oxyhydrogen allegedly endowed with special properties.
Properties
Oxyhydrogen will combust when brought to its autoignition temperature. For a stoichiometric mixture at normal atmospheric pressure, autoignition occurs at about 570 °C (1065 °F).[5] The minimum energy required to ignite such a mixture with a spark is about 20 microjoules.[5] At standard temperature and pressure, oxyhydrogen can burn when it is between about 4% and 95% hydrogen by volume.[5]
When ignited, the gas mixture releases energy and converts to water vapor, which sustains the reaction: 241.8 kJ of energy (LHV) for every mole of H2 burned. The amount of heat energy released is independent of the mode of combustion, but the temperature of the flame varies.[6] The maximum temperature of about 2800 °C is achieved with a pure stoichiometric mixture, about 700 degrees hotter than a hydrogen flame in air.[7][8][9] When either of the gases are mixed in excess of this ratio, or when mixed with an inert gas like nitrogen, the heat must spread throughout a greater quantity of matter and the temperature will be lower.[6]
Water torch
A "water torch" is a portable oxyhydrogen torch that combines a DC power supply and an electrolytic cell with a pressure gauge and flashback arrestor. Water is decomposed on-demand into oxyhydrogen, obviating the need for separate hydrogen and oxygen tanks. The original was designed in 1962 by William Rhodes and Raymond Henes of the Henes Manufacturing Co.[13] (now Arizona Hydrogen Manufacturing, Inc.) and marketed under the trade mark "Water Welder". A hypodermic needle was originally used for the torch tip.
https://en.wikipedia.org/wiki/GasolineFlammability
Like other alkanes, gasoline burns in a limited range of its vapor phase and, coupled with its volatility, this makes leaks highly dangerous when sources of ignition are present. Gasoline has a lower explosion limit of 1.4% by volume and an upper explosion limit of 7.6%. If the concentration is below 1.4% the air-gasoline mixture is too lean and will not ignite. If the concentration is above 7.6% the mixture is too rich and also will not ignite. However, gasoline vapor rapidly mixes and spreads with air, making unconstrained gasoline quickly flammable. Many accidents involve gasoline being used to get bonfires going; the gasoline readily vaporizes after being poured and mixes with the surrounding air.
https://en.wikipedia.org/wiki/Home_fuel_cellA home fuel cell, one of the available technologies for micro combined heat and power (microCHP) or microgeneration, is a residential-scaled energy system. A home fuel cell is an alternative energy technology that increases efficiency by simultaneously generating power and heat from one unit, on-site within a home. This allows a residence to reduce overall fossil fuel consumption, reduce carbon emissions and reduce overall utility costs, while being able to operate 24 hours a day.
Combined heat and power (CHP) fuel cells have demonstrated superior efficiency for years in industrial plants, universities, hotels and hospitals. Residential and small-scale commercial fuel cells are now becoming available to fulfill both electricity and heat demand from one system. Fuel cell technology in a compact system converts natural gas, propane, and eventually biofuels—into both electricity and heat, producing carbon dioxide (and small amounts of NOx) as exhaust. In the future, new developments in fuel cell technologies will likely allow these power systems to run off of biomass instead of natural gas, directly converting a home fuel cell into a renewable energy technology.
Disadvantages are slow ramping up and down rates, high cost and short lifetime.
https://en.wikipedia.org/wiki/Oxy-fuel_combustion_processOxy-fuel combustion is the process of burning a fuel using pure oxygen instead of air as the primary oxidant. Since the nitrogen component of air is not heated, fuel consumption is reduced, and higher flame temperatures are possible. Historically, the primary use of oxy-fuel combustion has been in welding and cutting of metals, especially steel, since oxy-fuel allows for higher flame temperatures than can be achieved with an air-fuel flame.
There is currently research being done in firing fossil-fueled power plants with an oxygen-enriched gas mix instead of air. Almost all of the nitrogen is removed from input air, yielding a stream that is approximately 95% oxygen. Firing with pure oxygen would result in too high a flame temperature, so the mixture is diluted by mixing with recycled flue gas, or staged combustion. The recycled flue gas can also be used to carry fuel into the boiler and ensure adequate convective heat transfer to all boiler areas. Oxy-fuel combustion produces approximately 75% less flue gas than air fueled combustion and produces exhaust consisting primarily of CO2 and H2O (see figure).
The justification for using oxy-fuel is to produce a CO2 rich flue gas ready for sequestration. Oxy-fuel combustion has significant advantages over traditional air-fired plants. Among these are:
The mass and volume of the flue gas are reduced by approximately 75%.
Because the flue gas volume is reduced, less heat is lost in the flue gas.
The size of the flue gas treatment equipment can be reduced by 75%.
The flue gas is primarily CO2, suitable for sequestration.
The concentration of pollutants in the flue gas is higher, making separation easier.
Most of the flue gases are condensable; this makes compression separation possible.
Heat of condensation can be captured and reused rather than lost in the flue gas.
Because nitrogen from air is not allowed in, nitrogen oxide production is greatly reduced.
Economically speaking this method costs more than a traditional air-fired plant. The main problem has been separating oxygen from the air. This process needs lots of energy, nearly 15% of production by a coal-fired power station can be consumed for this process. However, a new technology which is not yet practical called chemical looping combustion[1] can be used to reduce this cost. At present in the absence of any need to reduce CO2 emissions, oxy-fuel is not competitive. However, oxy-fuel is a viable alternative to removing CO2 from the flue gas from a conventional air-fired fossil fuel plant. However, an oxygen concentrator might be able to help, as it simply removes nitrogen.
In industries other than power generation, oxy-fuel combustion can be competitive due to higher sensible heat availability.
Oxy-fuel combustion is common in various aspects of metal production.
The glass industry has been converting to oxy-fuel since the early 1990s because glass furnaces require a temperature of approximately 2800 degrees F, which is not attainable at adiabatic flame temperatures for air-fuel combustion unless heat is regenerated between the flue stream and the incoming air stream. Historically, glass furnace regenerators were large and expensive high temperature brick ducts filled with brick arranged in a checkerboard pattern to capture heat as flue gas exits the furnace. When the flue duct is thoroughly heated, air flow is reversed and the flue duct becomes the air inlet, releasing its heat into the incoming air, and allowing for higher furnace temperatures than can be attained with air-fuel only. Two sets of regenerative flue ducts allowed for the air flow to be reversed at regular intervals, and thus maintain a high temperature in the incoming air. By allowing new furnaces to be built without the expense of regenerators, and especially with the added benefit of nitrogen oxide reduction, which allows glass plants to meet emission restrictions, oxy-fuel is cost effective without the need to reduce CO2 emissions. Oxy-fuel combustion also reduces CO2 release at the glass plant location, although this may be offset by CO2 production due to electric power generation which is necessary to produce oxygen for the combustion process.
Oxy-fuel combustion may also be cost effective in the incineration of low BTU value hazardous waste fuels.
Oxy-fuel combustion is often combined with staged combustion for nitrogen oxide reduction, since pure oxygen can stabilize combustion characteristics of a flame.
https://en.wikipedia.org/wiki/Engine_efficiencyEngine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-
1. Internal combustion (gasoline, diesel and gas turbine, i.e., Brayton cycle engines) and
2. External combustion engines (steam piston, steam turbine, and the Stirling cycle engine).
Each of these engines has thermal efficiency characteristics that are unique to it.
https://en.wikipedia.org/wiki/External_combustion_enginesAn external combustion engine (EC engine) is a heat engine where an (internal) working fluid is heated by combustion in an external source, through the engine wall or a heat exchanger. The fluid then, by expanding and acting on the mechanism of the engine, produces motion and usable work.[1] The fluid is then cooled, compressed and reused (closed cycle), or (less commonly) dumped, and cool fluid pulled in (open cycle air engine).
"Combustion" refers to burning fuel with an oxidizer, to supply the heat. Engines of similar (or even identical) configuration and operation may use a supply of heat from other sources such as nuclear, solar, geothermal or exothermic reactions not involving combustion; but aren't then strictly classed as external combustion engines, but as external thermal engines.
Working fluid
The working fluid can be of any composition and the system may be single phase (liquid only or gas only) or dual phase (liquid/gas).
Single phase
Gas is used in a Stirling engine. Single-phase liquid may sometimes be used.
Dual phase
Steam, as in a steam engine, is another option. In the case of the steam engine, or the Organic Rankine cycle the fluid changes phases between liquid and gas.
Everyman Standing Order 01: In the Face of Tyranny; Everybody Stands, Nobody Runs.
Everyman Standing Order 02: Everyman is Responsible for Energy and Security.
Everyman Standing Order 03: Everyman knows Timing is Critical in any Movement.