Raw materials for the chemical industry. Lecture on raw materials in the chemical industry

Raw materials are the starting material for the production of a chemical product that has value.

Classification of raw materials

By origin raw materials can be natural or synthetic.

Plant and animal raw materials are usually divided into food and technical.

According to reserves, raw materials can be renewable (water, air, plant and animal raw materials) and non-renewable (ores, hot minerals).

According to the chemical composition, raw materials can be inorganic (ores, minerals) and organic (oil, coal, natural gas).

According to their state of aggregation, raw materials can be solid (ores, coal, wood), liquid (water, oil) and gaseous (air, natural gas).

Raw materials for the organic synthesis industry

These are hydrocarbons obtained from fossil fuels (oil, coal, natural gas).

Oil

It is a heavy oily liquid containing:

1) paraffin hydrocarbons (alkanes) gaseous C 1 – C 4, liquid C 5 – C 15 and solid > C 15;

2) naphthenic hydrocarbons (cycloalkanes) – mono-, bi- and polycyclic structures with side chains;

3) aromatic hydrocarbons (arenes) - monocyclic (benzene, toluene, xylenes) and polycyclic (naphthalene, phenanthrene, anthracene, etc.);

4) oxygen-containing compounds (naphthenic acids, phenols, cresols, etc.);

5) sulfur compounds (hydrogen sulfide, sulfides, disulfides, mercaptans, thiophenes, etc.);

6) nitrogenous compounds (pyridine, quinoline and their derivatives);

7) salts of mineral acids;

8) organic complexes of vanadium, nickel and other metals;

9) other connections.

Oil refining is carried out using physical and chemical methods in the following technological sequence:

Field oil preparation consists in removing from it mineral impurities (water, sand, salts), dissolved gases (associated gas) and highly volatile liquids (gasoline). Oil is freed from impurities during the following operations:

Direct oil distillation designed to separate oil into separate fractions that differ in boiling point. Depending on the direction of use of the obtained distillates, a distinction is made between fuel and fuel-oil variants of direct race. Fuel oil refineries are focused only on the production of fuels and use direct-run AT (atmospheric tube) plants. In this case the following fractions are obtained:

Straight-run gasoline, boiling point. = 140С;

Naphtha, boil. = 140-180С;

Kerosene, boil. = 180-240С;

Diesel fuel, t kip. =180-350С;

Fuel oil – over 350С.

Straight-run gasoline has a low octane number and can be used as fuel for automobile internal combustion engines (carburetor fuel) only after adding compounds that increase knock resistance (tetraethyl lead, alkylates, methyl tert-butyl ether, etc.). Gasoline containing tetraethyl lead is called leaded; it is environmentally hazardous and is prohibited for use in European countries (currently prohibited in Russia). Until recently, most of the domestic A-76 gasoline contained tetraethyl lead. Gasolines AI-95 and AI-98 are unleaded (about 60% of the total amount of domestic gasoline). In addition to motor gasoline, the oil refining industry also produces solvent gasolines and extractant gasolines. Only a small part of the gasoline fraction is used as petrochemical feedstock.

Kerosene is used as a fuel for aircraft engines (jet fuel). Diesel fuel is used for compression ignition engines (diesels). Fuel oil is used as fuel for steam boilers, industrial furnaces and gas turbines (boiler fuel, gas turbine fuel); most of it goes for recycling.

If the oil refinery is focused on the fuel-oil option, then, using AVT (atmospheric-vacuum tube) units, in addition to the listed products, vacuum gas oil is obtained (boiling point = 350-500°C and oil distillates are distilled from the fuel oil under vacuum (transformer distillate, t boil = 300-400С, machine, t boil = 400-450°С and cylinder, t boil = 450-490°С). divided into:

Motor (for carburetor, diesel and aircraft engines);

Turbine;

Compressor;

Industrial;

Instrumentation;

Electrical insulating, etc.

In addition, lubricants (grease, anti-friction, friction, protective, dispersing, etc.) and special liquids (cooling, hydraulic, anti-corrosion, etc.) are made from oil distillates. The residue of vacuum distillation, boiling above 500°C – tar, is used to produce bitumen (road, construction, insulating), and also as a raw material in the processes of coking and deasphalting. From straight-run petroleum distillates, petroleum products such as paraffin, ceresin, naphthenic acids, naphthalene, etc. are obtained.

The most valuable components of oil are “light” petroleum products, boiling at temperatures below 350 0 at atmospheric pressure. They find the widest application. However, their content in oil is small, no more than 45% (gasoline 17%, kerosene 10%, diesel fuel 17%). Therefore, the so-called “heavy” oil fractions are subjected to special processing, which consists of reducing the molecular weight and chemical composition of hydrocarbons in order to reduce their boiling points. The processes used for this are called secondary and by their nature, unlike primary oil refining, they are chemical. All these processes are based on the following reactions:

Cleavage reactions S-S connections with the formation of alkanes and alkenes with a shorter chain;

Cleavage reactions S-N connections with the formation of alkenes with the same chain length and molecular hydrogen;

Isomerization reactions;

Reactions of polymerization, condensation, alkylation, etc., leading to the enlargement of molecules.

All these reactions are radical; the contribution of each type of reaction depends on the process conditions and the composition of the oil fraction being processed. There are thermal and catalytic secondary processes.

The most important secondary oil refining processes are:

Thermocracking– splitting of heavy hydrocarbons when they are heated to 450-500°C without air access, under high blood pressure. This is the oldest method of recycling; developed in 1890 by V.G. Shukhov. Currently, thermal cracking has limited use. It is used to produce boiler fuel from tar ( visbreaking) and in some other cases. In industry, depending on specific conditions, liquid-phase and vapor-phase cracking are used, as well as pyrolysis as a special type of high-temperature cracking (600-900С), carried out from various types raw materials for the purpose of producing olefins, primarily ethylene and propylene. Coking– high-temperature (600-1100С) decomposition of tar and heavy oil residues in order to obtain petroleum coke (material for the production of electrodes and metallurgical fuel). Coking is carried out under conditions under which the condensation reaction of the products of thermal decomposition of hydrocarbons occurs.

The use of a catalyst changes the mechanism of decomposition reactions to ionic, this increases the rate of some reactions by hundreds and thousands of times. The use of catalysts makes it possible to reduce the temperature of decomposition processes and change the relative contribution of individual reactions, i.e. direct the process predominantly in the direction of obtaining the required products.

The industry composition of the complex is quite wide, it includes: basic chemistry (production of salts, acids and alkalis), organic synthesis and processing of polymers, the basis for which is mining raw materials chemical industry(apatites, phosphorites, sulfur, etc.), as well as petroleum products. The starting material for production can be of either synthetic or natural origin, and is classified according to this parameter:

Mineral. Includes inorganic compounds: ores of heavy and non-ferrous metals, non-metallic and combustible minerals, as well as water and air.
Vegetable. All types of wood, cotton, oilseeds and sugar crops, rubber and medicinal plants.
Animal. Fat tissue and processed bone.
Synthetic. Hydrocarbon products of the coal and oil and gas processing industries.

Separately, the raw materials used in the chemical industry include several irreplaceable reagents, these include: formate and sodium nitrite, which significantly increase the performance characteristics of building materials and prevent corrosion, as well as saltpeter, a metallurgical raw material.

Organic synthesis for obtaining raw materials in the chemical industry

Despite the fact that the types of raw materials of the chemical industry are quite diverse, the basis of most popular products in this industry are primary hydrocarbons contained in oil. The processing of this mineral before it can be used in the production of products and materials consists of at least three stages:

field preparation - degassing, dehydration, desalting and stabilization;
direct race - separation of fuel fractions: gasoline, naphtha, kerosene, diesel, fuel oil from oils and lubricants for various purposes;
thermal and catalytic processing of petroleum distillates.

The main raw materials for the chemical industry are cracking products (alkanes and olefins). Such organic matter make it possible to obtain paraffin, ammonia fertilizers and jet fuel. Ethylene is the basis for a variety of materials from alcohol and aqueous compounds to a variety of plastics. Its compounds with other substances are used almost everywhere:

Ethyl alcohol is the most famous solvent and base for the production of cellophane and acetate fiber.
Dichloroethane makes it possible to create soft polyvinyl chloride plastics, from which linoleum, tiles and artificial leather are made, as well as latex, fiber packaging materials and coatings.
Isopropyl alcohol is made from propylene and is used to create acetone, phenol and plexiglass. Also, without this unsaturated carbon, it is impossible to synthesize allyl chloride, which acts as the main component of glycerol.
Butylene gas is converted into alcohols of the same name and is indispensable in the production of high-quality rubber.

Separately, it is worth noting ethylene-propylene rubbers with increased stability and resistance, which are indispensable for insulation needs in all industries.

Aromatic and gas hydrocarbons as raw materials for the chemical industry

Suppliers of raw materials for the chemical industry, the majority of whom work specifically with petroleum products, most often use the processing of gasoline fractions, catalytic reforming and pyrolysis of residual materials from the production of ethylene and propylene to produce organic compounds:

Benzene is the basis for the addition of additional substances that change its characteristics. The most commonly produced plastic polymers are styrene and phenol, as well as aniline, a versatile aromatic amine, to create a wide range of products. Phenylamine is used to make dyes, vulcanizing agents, polyurethanes, pesticides and even medications. In addition, it is benzene that increases the octane number in fuel and is present in extracted form in most varnishes, paints and detergents.
Toluene - known as the basis for TNT, can also be present in paints and solvents, and is included in the list of necessary carbohydrates for the creation of saccharin.
Xylene (O; M; P) takes part in the polymerization of plastics, plasticizers, and coatings, and is also the basis of film mylar capacitors and nylon.

Gas, as a raw material for the chemical industry, is a much more profitable material. The selling price, manufacturability and purity of the product for such hydrocarbons are much higher than for petroleum products, and the cost, on the contrary, is lower. In addition, gas processing and transportation schemes are easily automated and are often carried out in a continuous cycle.

Methanol is a multifunctional alcohol, the basis of antifreeze, formaldehyde, resins and plastics, as well as a disinfectant, antiseptic and deodorizing agent. Raw materials for the chemical industry in Russia are mined, synthesized and processed by several hundred industries of various sizes, and this industry is today considered one of the most promising and profitable.

Examples of raw materials for the chemical industry at the exhibition

Expocentre Fairgrounds is the largest domestic organizer of exhibition events and the creator of its own successful projects aimed at stimulating the development of various industries. The “Chemistry” exposition this year will bring together domestic and foreign representatives interested in promoting and improving business in the chemical industry sector.

Expocentre is pleased to offer its guests a new, completely renovated level, designed specifically for the comfortable installation of demonstration pavilions of any complexity. The exhibition traditionally brings together representatives of the most influential companies, research institutes, government sectoral departments and a lot of journalists. One of the topics of discussion at this event is raw materials for the chemical industry and the possibilities for modernizing production and its preparation.

Raw materials are materials intended for further processing in production. In fact, this is where the production of any product begins. It is difficult to overestimate the role of the source material, since the quality of the product depends on this. Today there are a huge number of different groups, subgroups and types of raw materials. Let's try to understand this diversity.

What are raw materials for production

Collected or mined materials are usually processed to make them marketable. In the future, they either go on sale or continue to participate in subsequent ones until they reach the stage of the final product.

Types of raw materials

Classification of raw materials is a very conditional concept. It is customary to distinguish two main groups: industrial and agricultural. Industrial includes minerals and energy resources. Agricultural raw materials include grains, dairy products, meat, and medicinal plants. All types of raw materials can be divided into two more groups: they can be primary (directly mined or collected) and secondary (in the form of a by-product or The secondary group of materials is widely used in industry, which can significantly reduce costs. By origin, all types of raw materials can be divided into 4 subgroups:

Plant origin (cereals, herbs).
Animal origin (dairy products, animal excrement).
Mineral coal).
Biosphere (water and air).

Use of raw materials in production

Today there are a huge number of industries. The list of traditional industries is updated daily with new names, which means new raw materials are being developed and used. This is due to both growing global demand and developing technologies. The most pressing area today is the development of energy resources. If a hundred years ago people were able to obtain energy from oil and coal, today other sources are being actively developed, for example. There is an alternative technology for generating electricity based on natural fermentation processes, when cow dung acts as an energy carrier. But production such as the production of cotton fabric has remained virtually unchanged for many centuries. The process itself has been improved and mechanized, but the raw materials are cotton bolls - just as it was 3-4 centuries ago. And the food industry is constantly changing. The manufacturer's desire to reduce costs results in a search for new types of the original product. Natural raw materials are best option. However, unfortunately, in order to save money, it is often replaced with artificial one. Thus, today we can observe a situation in which some manufacturing industries continue to use some raw materials for centuries, while others develop technologies and develop new types of raw materials.

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Industrial raw materials consist of only semi-fruits from grayish-green to brownish-green color, aromatic odor and sweetish-spicy taste characteristic of fennel. Basic and limiting standards are given below.

Industrial raw materials consist of leaves of different sizes with petioles of normal color and a pleasant smell, reminiscent fresh cucumbers. Pure raw materials contain 47 - 58% leaf blades, 42 - 53% petioles. The content of leaf blades can be increased by 10 - 15% by cultivating violets on irrigated lands.

Industrial raw materials are pieces of rhizomes at least 2 cm long, about 1 - 2 cm thick, not cleared of the suberized layer, cylindrical, slightly flattened and curved, for the most part longitudinally cut. On the surface are visible semi-lunar wide scars from fallen leaves and numerous round small warty outgrowths - traces of fallen and cut roots. The outside color of the rhizome is yellowish or reddish-brown, sometimes greenish-brown; in a fracture - yellowish or pinkish, sometimes greenish; leaf scars are dark brown.

Industrial raw materials are classified: by origin - mineral, plant and animal; by reserves - non-renewable and renewable; by chemical composition - inorganic and organic; according to the state of aggregation - solid, liquid and gaseous.

The industrial raw material is the entire above-ground part of the plant, with the exception of woody branches. High-quality raw materials contain 60% leaves and 40% stems.

The industrial raw material is the entire above-ground part of the bush without lignified branches, cut along the leafing line during the phase of mass flowering of the inflorescences of the lateral branches and the browning of the seeds on the central inflorescence.

Industrial raw materials are young leafy branches. Their oil content ranges from 0 5 to 1 0% and depends on the degree of foliage and the content of essential oil in the leaves. About 40 components have been identified in the essential oil, among which cineole is the main one.

The industrial raw material, mainly consisting of paraffins of normal structure, is cogasin, synthesized according to the Fischer and Tropsch method. It completely lacks cyclic compounds.

Industrial raw materials are peeled dry rhizomes. Processing fresh or poorly peeled rhizomes gives essential oil Low quality.

INTRODUCTION

Nowadays, metal cutting is becoming increasingly higher value. This is happening primarily due to an increase in production volumes that conventional manual cutting cannot cope with, as well as due to the significant development of cybernetics and automation, due to which the manufacture of CNC machines for figured cutting of parts and workpieces does not represent technical complexity and the payback of this equipment lies within 0.5--1 year. The production of CNC machines has significantly facilitated the work of the cutter, increased labor productivity and the accuracy of manufacturing the part (workpiece), due to which the role of metal cutting in blank production has increased.

One of the most labor-intensive operations currently remains the preparation of edges for welding. Developments in this area in the territory former USSR have not yet been successful. Foreign similar devices are not widely used in our country, primarily because of their high cost.

Raw materials in industry: classification, extraction, enrichment of raw materials

In the twentieth century, the rapid development of the mineral processing industry led to the accumulation of thousands of tons of waste, which contained silicates and aluminosilicates of calcium, magnesium, potassium and sodium. Industry building materials- the main consumer of technogenic raw materials, is the final link in the integrated use of natural resources and can solve many environmental problems.

In concrete technology, of particular interest are those by-products that are chemically active materials and participate in the processes of structure formation.

According to the classification of Bozhenov P.I. Technogenic raw materials according to their state of aggregation at the time of their separation from the main technological process are divided into three classes:

1. Products that have not lost their natural properties (quarry residues from the extraction of rocks; residues after the enrichment of rocks for minerals).

2. Artificial products obtained as a result of deep physical and chemical processes, formed:

When processing below Tspec;

Subject to complete or partial melting of the feedstock;

When deposited from a melt at T< 200 °С.

3. Products formed as a result of long-term storage of waste in dumps (liquid: solutions, emulsions, mud; solid: crushed stone, sand, powders).

Class 1 mineral raw materials are by-products of the non-metallic building materials industry and mining and processing plants (GOK). “Tailings” from GOK enrichment, containing mainly quartz, feldspars, calcium and magnesium carbonates, can be used as fillers for the production of concrete and mortar mixtures, if the grain size meets the requirements of current standards.

Class 2 technogenic raw materials are metallurgical slag, ashes and slags formed during combustion solid fuel at thermal power plants, sludge from the alumina and chemical industries, gas cleaning dust from ferrosilicon production and others. These products, differing greatly in chemical and mineralogical composition, can be used both as a binding material and as mineral additives in concrete and mortars.

Class 3 products are not yet widely used in the production of building materials due to the variety of processes occurring in dumps. The most thoroughly studied are burnt rocks from the coal mining industry, which can be used as inactive mineral components of concrete and mortar mixtures.

The numerator of the above formula shows how many percent of CaO remains for the formation of calcium silicates, and the denominator shows how much CaO is needed for the formation of calcium monosilicates. If Kosn = 1, CS is formed; when Kosn = 1.5, we should expect the formation of CS and C2S; when Kosn is 2, C2S is formed.

By chemical characterization(Kosn) mineral materials are divided into 5 groups:

From 1.6 to + oo - ultrabasic (have astringent properties); -- from 0.0 to 0.8 - acidic (raw materials for ceramic materials, glass, mineral wool);

From 0.0 to - oo - ultra-acidic (raw materials for ceramics, glass, etc.).

Effective raw materials for the production of active mineral finely dispersed additives in concrete and mortars are fly ash from thermal power plants, which has a specific surface area of the order of Sd = 3000...3500 cm2D and microsilica, which has Syd - 20,000...22,000 cm2/g. These wastes do not require special training when they are introduced into a concrete or mortar mixture. However, it should be taken into account that when using ashes and slags, their properties largely depend on the chemical composition and properties of the feedstock and can vary widely.

Pozzolanic additives include ultrafine waste from ferroalloy production, containing more than 90% amorphous silica and consisting of finely dispersed spherical glassy particles. The main prerequisite for the use of such additives in the production of binders and concrete is their ability, when mixed with lime during the first 5...7 hours of normal hardening, to bind up to 7% CaO into low-basic calcium hydrosilicates with a ratio between lime and additive of 1:1 by weight.

There is evidence that 1 kg of microsilica can replace 3...4 kg of cement in concrete while providing the same strength at 7 and 28 days of age. An important difference between the additive is that the effect of the pozzolanic reaction manifests itself in the early stages of hardening more intensely than when using fly ash.

The use of ferroalloy production waste and other similar mineral substances in concrete and mortars is a promising direction in concrete technology, since, being a secondary cementitious material, they significantly contribute to improving the technical and economic efficiency concrete.

During the smelting of cast iron in blast furnaces, a large number of slags, which are advisable to use as additives in concrete and mortars. To produce active dispersed additives, it is advisable to select blast furnace slag melts formed during hot or normal “running” (thermal conditions) of a blast furnace. Rapidly cooled granular melts are most suitable for obtaining additives, so it is better to use vitrified slags as additives.

Some slag melts, as a result of silicate decomposition, turn into fine powder “blast-furnace flour”, which almost entirely consists of hydraulically active belite and can be used as an active mineral additive without additional grinding, which is very economically feasible.

A large reserve for the production of building materials is secondary raw materials from non-ferrous metallurgy. In the aluminum industry, the main man-made product is sludge waste, the amount of which in dumps amounts to tens of millions of tons. When processing bauxite into alumina, red bauxite mud is formed, which is characterized by a number of valuable properties: high degree dispersion, constant chemical composition and water-solid ratio, significant content of sesquioxides.

To determine the optimal amount of mineral additives, it is necessary to conduct experimental studies in order to establish the dependence of the change in concrete strength on the amount of additive: Rb =/(MD). For this purpose, samples are made from a mixture of cement and various amounts of additives, which, after 7 and 28 days of hardening at normal conditions or immediately after steaming they are tested for strength.

Research has established that the nature of the change in the strength of concrete with mineral additives is associated with the ability of the additives to work as microfillers. At small dosages of the additive, its particles, evenly distributed in the dough, play the role of inclusions that reduce the homogeneity and strength of the cement stone. At optimal content Additives in the “cement + mineral additive” system increase the strength of concrete, reaching a maximum. In this case, the particles of the mineral additive play the role of elements of the structure of the cement stone. A further increase in dispersed material leads to dilution of the cement with the additive and disruption of direct contacts between cement particles, which leads to a decrease in strength. It is necessary to distinguish between the economically optimal amount of a mineral additive, found from the condition of minimizing cement consumption or the cost of concrete, and the structurally optimal amount, determined by the physical state of the system or structure, associated with the redistribution of particles in the cement paste.

Preference should be given to the structurally optimal amount of the additive, because concrete with such a structure organization corresponds to the maximum strength value - the response of the “C+MD” system to the optimization of the dispersion medium (cement paste) in concrete.