Coke gas: composition, use, production

Long ago, coke oven gas was considered a by-product in the process of making coke, so often it was even discharged into the atmosphere (which is very in vain!). Later, the gas was used to heat coke ovens, and already today it is given to extraneous consumers for everyday use and for other needs. How do we get coke oven gas and what is its composition? In this article all aspects of the issue are considered and concrete examples of the use of gas are given.

Historical aspect

The history of coke oven gas began even in the late 19th and early 20th centuries. Even then it was used for lighting, heating and, therefore, for cooking and other household matters. At that time, the industrial revolution and urbanization broke out. Production of by-products, coal tar and ammonia began to serve as important components, namely raw materials, in the manufacture of chemical dyes and in the chemical industry as a whole. Thus, absolutely all types of artificial pigments were made from resin and coke oven gas.

стал широко использоваться в печах для изготовления промышленной продукции, в двигателях газового типа функционирования и, конечно же, в роли сырья при производстве химических продуктов. In addition, coke oven gas has become widely used in furnaces for manufacturing industrial products, in gas-type engines of operation and, of course, as raw materials in the production of chemical products.

Production of coke oven gas

The production of coke oven gas occurs simultaneously with the production of coke at coke plants by dry distillation of coal. It is important to note that this process must necessarily take place at a temperature of 900-1200 degrees. As noted above, during the initial stages of generation, gas was considered a by-product, so it often came out into the atmosphere. A little later, coke oven ovens were heated with coke oven gas. Thus, the consumption of gas for personal needs has undergone a significant reduction (up to almost 60%), the rest has already belonged to other categories of consumers, for example, for heating furnaces of metallurgical production, the temperature of which is extremely high, or for household affairs. To date, absolutely all gas belongs to outside consumers. Why? The fact is that coke oven gas is very high-calorie, which means that it is possible to use cheaper gas for heating furnaces. A vivid example of this can serve as liquefied gas. By the way, the basis is propane-butane mixture.

Coke gas: composition

As it turned out, out of the many gases of artificial origin, the gas considered in the article and obtained in the process of coking coal is of great importance. It should be noted that, from a practical point of view, its composition undergoes considerable fluctuations. It depends, as a rule, on the raw materials used as fuel, on the differences in operating modes, on the physical condition of coke ovens and so on. Its heat of combustion lies in the range of 15-19 MJ / m3. If we consider the components of a given gas as a percentage of the volume, then the following picture is formed:

• H2: 55-60.
• CH4: 20-30.
• CO: 5-7.
• CO2: 2-3.
• N2: 4.
• Unsaturated hydrocarbons: 2-3.
• O2: 0.4-0.8.

It is important to note that the coke oven gas (formula: H2CH4NH3C2H4) has a density at zero degrees from 0.45 to 0.50 kg / m3, the heat capacity is equal to 1.35 kJ / (m3 · K), and the temperature accompanying the ignition process, Reaches 600-650 degrees.

Formula of substance

As it was explained above, the composition of coke oven gas includes such substances as hydrogen (H2), methane (CH4), ammonia (NH3) and ethylene (C2H4). As an example, the following composition of purified coke oven gas will be expedient:

It is important to note that the composition of the gas in question strictly depends on the temperature regime of the coking process and its duration. Also the huge role played by the quality of coal being processed. Thus, the higher the temperature regime of the coking process, the greater the level of decomposition of hydrocarbons, and hence the higher content of hydrogen and carbon monoxide in the gas . Accordingly, the carbon dioxide content , on the contrary, will be lower.

The need for cleaning coke oven gas

Today, the problem of the need to clean coke oven gas is quite acute, because this composition adversely affects the ecological aspect of life. Thus, modern society strives to improve the corresponding technologies. необходима для эффективности деятельности заводских механизмов, потому что цианид водорода, содержание которого в коксовом газе достаточно велико, служит основной причиной коррозии профессионального оборудования. Coke oven gas cleaning is necessary for the efficiency of the plant mechanisms, because hydrogen cyanide, whose content in coke oven gas is large enough, is the main reason for corrosion of professional equipment. In addition, when coke oven gas is formed, ammonia is required. This substance is extremely detrimental to not only the pipelines, but also the environment, because in the end it gets there. The result of the operations considered is a high level of loss of products of chemical origin for a given plant, as well as a significant degree of release of gases and waste of liquid origin into the atmosphere.

Coke gas cleaning process

влечет за собой ряд проблем, что в полной мере аргументирует необходимость его очистки. As it turned out, the production of coke oven gas entails a number of problems, which fully justifies the need for its purification. To date, the most effective method is the invention described in this chapter, which is widely used in the coke-chemical industry. First of all, it is necessary to flush the gas with a solution of ammonium phosphate in the absorber, which must necessarily be equipped with plates. Next, treat the coke oven gas before it enters the dish area of the absorber with this solution. At the same time, the specific consumption of the circulating solution should be 1.0-1.2 l / m3 of gas, then its density will be equal to 1.195-1.210 kg / l. This method of cleaning coke oven gas, as noted above, is today often used in the relevant field of industry, because it is the most effective.

Coke oven gas: application

To date, coke oven gas is widely and safely used in the society as a fuel in metallurgical plants, as well as in municipal economic activities and as a raw material for production. As it turned out, hydrogen is extracted from the coke oven gas, which is simply necessary for the synthesis of ammonia by means of a known method of condensing the functioning under the condition of a low temperature regime. As a result of this operation, a fraction is formed, serving as a qualitative raw material for various kinds of syntheses. применяется как топливо, и когда он служит сырьем для производства химической продукции). It should be noted that the admixture in the coke oven gas of hydrogen sulphide is absolutely undesirable in any case (and when coke oven gas is used as fuel and when it serves as raw material for the production of chemical products). That is why the cleaning process is so necessary, fully considered in the previous chapter.

Properties of gas

. In conclusion, it will be expedient to consider the physical properties of the coke oven gas . Thus, the calorific value of it is from 3600 to 3700 kcal / m3, the specific gravity in the composition of the substance varies from 0.45 to 0.46 kg / m3 (which is almost three times lighter than air), the maximum temperature regime of its combustion is equated To 2060 degrees, and the process itself is accompanied by a red flame.

It is important to note that the gas in question is explosive if it is combined with air. Moreover, the explosive limit of the lower level by volume is 6 percent of the gas (the rest is air), and the upper level of explosivity reaches 32 percent of the gas (the rest is air). The temperature regime of ignition is equal to 550 degrees, and for the combustion of 1 cubic meter of gas, approximately 5 cubic meters of air are needed. Coke gas is not endowed with color and taste, but it has a pungent smell of naphthalene, rotten eggs, which can be explained by the content of hydrogen sulphide in its composition.