Glossary of Terms - H2

This glossary covers words, phrases and acronyms that are commonly used in various catalytic reforming processes for H2 production. Some words may have different meanings when used in other contexts.

Air: The mixture of oxygen, nitrogen, and other gases that, with varying amounts of water vapor, forms the atmosphere of the earth.

Bio-mass: Biomass as a renewable energy source, refers to living and recently dead biological material that can be used as fuel or for industrial production.

Bio-gas: Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Biogas originates from biogenic material and is a type of biofuel.

Bio-fuel: Biofuel is defined as solid, liquid or gaseous fuel obtained from relatively recently lifeless biological material and is different from fossil fuels, which are derived from long dead biological material.

Carbon (C): An atom and primary constituent of hydrocarbon fuels. Carbon is routinely left as a black deposit on engine parts, such as pistons, rings, and valves, by the combustion of fuel.

Carbon Dioxide (CO2): A colorless, odorless, noncombustible gas that is slightly more than 1.5 times as dense as air and becomes a solid (dry ice) below -78.5°C. It is present in the atmosphere as a result of the decay of organic material and the respiration of living organisms. It is produced by the burning of wood, coal, coke, oil, natural gas, or other fuels containing carbon.

Carbon Monoxide (CO): A colorless, odorless, tasteless, poisonous gas that results from incomplete combustion of carbon with oxygen.

Catalyst:A chemical substance that increases the rate of a reaction without being consumed; after the reaction, it can potentially be recovered from the reaction mixture and is chemically unchanged. The catalyst lowers the activation energy required, allowing the reaction to proceed more quickly or at a lower temperature. In a fuel cell, the catalyst facilitates the reaction of oxygen and hydrogen. It is usually made of platinum powder very thinly coated onto carbon paper or cloth. The catalyst is rough and porous so the maximum surface area of the platinum can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the membrane in the fuel cell.

Dry Reforming (CDRM): is a process where methane and carbon dioxide react to create syngas or synfuel (CO + H2). It is termed as dry reforming because no steam is utilized in this process, unlike the steam reforming.

Ethanol (CH3CH2OH): An alcohol containing two carbon atoms. Ethanol is a clear, colorless liquid and is the same alcohol found in beer, wine, and whiskey. Ethanol can be produced from cellulosic materials or by fermenting a sugar solution with yeast.

Fuel cell: It is an electrochemical device that produces electricity from fuel (chemical source).

Gasification: The conversion of a substance into a gas. The conversion of coal, petroleum or biomass into a gas mixture containing carbon dioxide, carbon monoxide and hydrogen in the presence of oxygen. The gas mixture produced (syngas) can then be treated with steam to produce more hydrogen. Gasification occurs through chemical reactions at high temperature and often at high pressure.

Glycerol (C3H5(OH)3): It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. It is a byproduct of bio-diesel production.

H2 Economy: Is a proposal for the distribution of energy by using hydrogen.

Hydrocarbon (HC): An organic compound containing carbon and hydrogen, is usually derived from fossil fuels, such as petroleum, natural gas, and coal.

Hydrogen (H2): Hydrogen (H) is the most abundant element in the universe, but is generally bonded to another element. Hydrogen gas (H2) is a diatomic gas composed of two hydrogen atoms and is colorless and odorless. Hydrogen is flammable when mixed with oxygen over a wide range of concentrations.

Hydrogen Sulfide (H2S): Is a colorless, toxic and flammable gas with a typical foul odor of rotten eggs and flatulence.

Landfill Gas (LFG): Is a gas produced from landfill sites. It is mostly comprised of methane and carbon dioxide and also contains varying amounts of nitrogen, oxygen, water vapor, sulfur and a variety of contaminants like hydrogen sulfide, siloxanes etc.

Membrane: A membrane is a layer of material which serves as a selective barrier between two phases and remains impermeable to specific particles or group of particles or substances when exposed to the action of a driving force. Some components are allowed passage by the membrane into a permeate stream, whereas others are retained by it and accumulate in the retentate stream.

Membrane Reactor (MR): Is a piece of chemical equipment that combines a catalyst-filled reaction chamber with a membrane to extract either reactants or products selectively. Chemical reactors making use of membranes are usually referred to as membrane reactors. MRs are an example for the combination of two unit operations in one step.

Methane (CH4): It is the simplest alkane, and the principal component of natural gas.

Oxygenated Hydrocarbons (Oxy-HC): Are hydrocarbon compounds, which contain oxygen as a part of their chemical structure. They are often referred as oxygenated fuels.

Rafinate or Retentate: The gas mixture that results when hydrogen is removed from reformate.

Reactant: A substance that enters into chemical combination with another substance.

Reactor: Device or process vessel in which chemical reactions take place.

Reformate: The hydrogen-rich gas mixture that results from processing hydrogen containing fuels in a reformer.

Reforming: A chemical process in which hydrogen-containing fuels like natural gas react with steam, oxygen, or carbon dioxide to produce a hydrogen-rich gas stream.

Renewable Energy: A form of energy that is never exhausted because it is renewed by nature.

Steam Reforming: A process where hydrogen is produced from steam and a hydrocarbon fuel (natural gas).

Syngas: a gas mixture containing carbon monoxide, hydrogen and other trace gases. It is generated by gasifying fossil fuels or biomass.

Water Gas Shift Reaction (WGSR): Is a chemical reaction in which carbon monoxide reacts with water to form carbon dioxide and hydrogen. It is an important industrial reaction in the production of hydrogen.

Acronyms

BMG: Biomass Derived Gas

CDRM: Carbon dioxide Dry Reforming of Methane

IPCC: Intergovernmental Panel on Climate Change

LFG: Land Fill Gas

MR: Membrane Reactor

OxyHCs: Oxygenated Hydro Carbons

SRM: Steam Reforming of Methane

WGSR: Water Gas Shift Reaction