Gaseous fuel. They are mainly made up of hydrocarbons , that is, molecular compounds of carbon and hydrogen . The properties of different gases are dependent on the number and arrangement of the atoms of carbon and hydrogen in their molecules. All of these gases are odorless in their pure state, as is the case with the Carbon Monoxide (toxic) that they sometimes contain. That is why it is common to add sulfur compounds to commercial gas.; These compounds, which are sometimes naturally present in gas, have an unpleasant odor and serve to warn of a leak in gas pipes or appliances. In addition to their combustible components, most gaseous fuels contain varying amounts of Nitrogen and water .
Summary
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- 1 Principle of operation
- 2 Coal gas
- 3 Producing and blast furnace gas
- 4 Bottled gas
- 5 Sources
Operating principle
The devices used to burn gas and produce heat or lighting consist of a combustion nozzle and some system to mix air with the gas before reaching the nozzle, as happens for example in the Bunsen burner , invented by the German chemist Robert Wilhelm Bunsen (see Lamp ).
The gaseous fuels currently used are coal gas, obtained by destructive distillation of coal (see Coke ), producer and blast furnace gases, the result of the interaction of water vapor , air and coal, natural gas, extracted from underground gas fields, and bottled gases, made up of the lightest hydrocarbons.
Coal gas
The most important coal gasification processes are aimed above all at the production of gas known as ‘pipeline-type’, whose properties are more or less equivalent to those of natural gas. The gas from the coal, in addition to meeting the pumping and heating specifications, must meet strict limits regarding the content of Carbon Monoxide , sulfur , inert gases and water . To meet these standards, most coal gasification processes culminate in gas cleaning and methanation operations .
Various hydrogasification methods are currently used in which hydrogen reacts directly with carbon to form methane ; These processes bypass the intermediate step of producing synthesis gas, hydrogen, and carbon monoxide before producing methane. Other methods are the carbon dioxide acceptor process , which uses dolomite ¸ a limestone, and the molten salt process . Other gases manufactured in the past from coal and coke, such as lighting gas or coke oven gas, are of little importance today.
Producing and blast furnace gas
Gas burning process
Producer gas is a type of water gas, a term applied to gases obtained through water vapor processes . It is produced by burning low-quality fuel (such as lignite or bituminous coal ) in a closed container called a producer through which a continuous flow of water and air vapor is passed at the same time. The resulting gas contains around 50% nitrogen , derived from the air present in the producer, and its calorific value is approximately 30% of that corresponding to coke oven gas.
Blast furnace gas, produced by the interaction of limestone, iron ore and carbon in blast furnaces, has a certain calorific value due to its carbon monoxide content , but contains 60% nitrogen. Huge amounts of this gas are produced during furnace operation; most are used to heat the air stream for the furnace and to operate the compressors that drive the blast. The calorific value of blast furnace gas is 16% of that of coke oven gas. Deposits oil almost always associated carry a certain amount of natural gas that comes to the surface along with it when a drilled well. However, there are wells that provide natural gas only.
This contains important organic elements as raw materials for the oil and chemical industry . Before using natural gas as fuel, the heaviest hydrocarbons, such as butane and propane, are extracted . The remaining gas, the so-called dry gas, is distributed to domestic and industrial users as fuel. This gas, free of butane and propane, is also found in nature. It is composed of the lightest hydrocarbons, methane and ethane , and is also used to make plastics , drugs and dyes .
Bottled gas
Various hydrocarbons such as propane , butane, and pentane , or mixtures of these gases, are liquefied for use as fuel. Thanks to so-called bottled gases, which are usually stored in metal cylinders or tanks, kitchens or stoves can be used in locations that lack a centralized gas supply. These bottled gases are produced from natural gas and oil .
