Production of elemental sulfur at the refinery. Refineries under construction and projected in Russia

At refineries, sulfur is obtained from technical hydrogen sulfide. At domestic refineries, hydrogen sulfide is mainly emitted with the help of 15% aqueous solution monoethanolamine from the respective streams from hydro-treatment and hydrocracking units. Hydrogen sulfide regeneration units from saturated solutions of monoethanolamine are mounted at hydrotreatment units for diesel fuel, kerosene or gasoline, hydrocracking or directly at sulfur production units, where monoethanolamine solutions containing hydrogen sulfide are collected from a large group of units. The regenerated monoethanolamine is returned to the hydrotreaters, where it is reused to recover hydrogen sulfide.

At sulfur production units built according to the projects of the Giprogazoochistka Institute, hydrogen sulfide-containing gas is used, in which at least 83.8% (vol.) hydrogen sulfide. The content of hydrocarbon gases in the raw material should be no more than 1.64% (vol.), water vapor (at 40 ° C and 0.05 MPa) no more than 5% (vol.) and carbon dioxide no more than 4.56% (vol. .).

The plants produce high-quality sulfur with its content in accordance with GOST 127-76 of at least 99.98% (mass); other grades contain sulfur not less than 99.0 and 99.85% (wt.). The yield of sulfur from its potential content in hydrogen sulfide is 92–94% (mass). With an increase in the concentration of hydrogen sulfide in the raw material, for example, up to 90% (vol.), the yield of sulfur from the potential increases to 95-96% (mass.).

The main stages of the process of sulfur production from commercial hydrogen sulfide: thermal oxidation of hydrogen sulfide with atmospheric oxygen to produce sulfur and sulfur dioxide; interaction of sulfur dioxide with hydrogen sulfide in reactors (converters) loaded with a catalyst.

The thermal oxidation process takes place in the main furnace, mounted in the same unit with the waste heat boiler.

Mixing and heating of hydrogen sulfide and sulfur dioxide is carried out in auxiliary furnaces. Catalytic sulfur production is usually carried out in two stages. Like thermal, catalytic sulfur production is carried out at a slight excess pressure. The technological scheme of the sulfur production unit designed by the Giprogazoochistka Institute is shown in Figure XI 1-4.

Raw material - hydrogen sulfide-containing gas (technical hydrogen sulfide) - is released from entrained monoethanolamine and water in the receiver / and heated to 45-50 ° C in steam heater 2. Then 89% (mass.) Of the total amount of hydrogen sulfide-containing gas is introduced through the guide nozzle into the main furnace 4. Air is supplied to the furnace through the same nozzle by an air blower 5. The consumption of raw materials and the specified volumetric ratio of air: gas, equal to (2-3) : 1, are supported automatically. The temperature at the process gas outlet from the main furnace is measured with a thermocouple or pyrometer. Then the gas is cooled successively inside the first and then the second convective bundle of the waste heat boiler of the main furnace. Condensate (chemically purified water) enters the waste heat boiler from deaerator 3, from the top of which the resulting water vapor is discharged. In the waste heat boiler of the main furnace, steam is generated at a pressure of 0.4–0.5 MPa. This steam is used in the steam tracers of the pipelines of the installation. In the pipelines through which sulfur is transported, as well as in the storage of liquid sulfur, a temperature of 130-150 ° C is maintained. The sulfur condensed in the waste heat boiler flows through the hydraulic valve 7 into the underground storage 20. The process gas enriched with sulfur dioxide from the waste heat boiler is sent to the mixing stage of the auxiliary furnace I of the catalytic stage I, 11. Into the combustion chamber of the furnace on- i - hydrogen sulfide-containing gas steps (^ 6 wt. % of the total) and air from the blower 5.

The volumetric ratio air:gas, equal to (2 - 3) : 1, is also automatically maintained here. The mixture of combustion products from the mixing chamber of the auxiliary furnace 11 enters from top to bottom into the vertical reactor (converter) of stage I 8. In the reactor, a catalyst, active alumina, is loaded onto a perforated grate. As the catalyst passes, the gas temperature increases, which limits the height of the layer, since with an increase in temperature, the probability of catalyst deactivation increases. The process gas from the reactor 8 is sent to a separate section of the condenser-generator 10. The condensed sulfur flows through the hydraulic seal 9 into the underground sulfur storage 20, and the gas is sent to the mixing chamber of the auxiliary furnace II of the catalytic stage 14. The steam generated in the condenser-generator pressure of 0.5 or 1.2 MPa is used at the plant or is discharged into the factory steam pipeline. Hydrogen sulfide-containing gas (5% by weight of the total) and air from blower 5 (in a volume ratio of 1:2–3) enter the combustion chamber of furnace 14. A mixture of combustion products of hydrogen sulfide-containing and process gases from the mixing chamber of the auxiliary furnace 14 enters the reactor (converter) II stage 16, which is also loaded with active alumina. From the reactor, the gas enters the second section of the condenser-generator 10, where the sulfur condenses and flows into the underground storage 20 through the hydraulic seal 17. -lets. Sulfur flows through the hydraulic seal 18 into the storage 20. The gas is sent to the afterburner 12, where it is heated to 580-600 ° C due to the combustion of fuel gas. Air for fuel combustion and afterburning of hydrogen sulfide residues to sulfur dioxide is injected with fuel gas due to thrust chimney 13.

Liquid sulfur from underground storage 20 is pumped out by pump 19 to an open storage of lump sulfur, where it solidifies and is stored before being loaded into railway cars. Sometimes liquid sulfur is passed through a special drum, on which flake sulfur is obtained as a result of rapid cooling, then it is poured into wagons.

Technological mode of the sulfur production unit:

The amount of hydrogen sulfide-containing gas supplied to the installation, m 3 / h Overpressure, MPa Hydrogen sulfide-containing gas supplied to the furnaces air from blowers in furnaces in the deaerator Gas temperature, °С in the main furnace at the outlet of the waste heat boiler at the entrance to the reactors (converters) at the outlet of the 1st stage reactor at the outlet of the second stage reactor gas at the outlet of the condenser-generator in the sulfur trap at the outlet of the afterburner Vacuum in the chimney, Pa oxygen sulfur dioxide hydrogen sulfide

360-760 0,04-0,05 0,05-0,06 0,03-0,05 0,4-0,5 1100-1300 155-165 230-250 290-310 240-260 140-160 390-490 4,5-6 1,45 absence

Sulfur is widely used in the national economy - in the production of sulfuric acid, dyes, matches, as a vulcanizing agent in the rubber industry, etc. The use of sulfur high degree purity also predetermines the high quality of the products obtained. The presence of hydrocarbons in the hydrogen sulfide-containing gas and their incomplete combustion lead to the formation of carbon, while the quality of sulfur deteriorates, and the yield decreases.

Analysis of the composition of process gases at various stages of sulfur production makes it possible to correct the distribution of hydrogen sulfide-containing gas in the furnaces, the ratio of oxygen and raw materials at the inlet to the furnaces. Thus, an increase in the proportion of sulfur dioxide in the flue gases after the dozhnga above 1.45% (vol.) indicates an increased content of unreacted hydrogen sulfide in the process of obtaining sulfur. In this case, the air flow to the main furnace is corrected, or the hydrogen sulfide-containing gas is redistributed among the furnaces.

The most important condition for the uninterrupted operation of the installation is to maintain the temperature ISO -150°C liquid sulfur in pipelines, equipment, underground storage. During melting, sulfur turns into a mobile yellow liquid, but at 160 ° C it turns brown, and at a temperature of about 190 ° C it turns into a viscous dark brown mass, and only with further heating does the viscosity of sulfur decrease.

From the official registers of the Ministry of Energy of the Russian Federation, it is known that today several oil refineries are being built in our country. A huge number of refineries are still in the formal design stage, according to data Department of Energy registry.

Total order will be covered 18 regions of Russia, and in some regions, even several refineries.
The main number of new refineries will be located in the Kemerovo region:

• Itatskiy Refinery LLC
• LLC Oil Refinery Northern Kuzbass
• Anzherskaya Oil and Gas Company LLC

Rosneft builds a plant called Eastern petrochemical complex 30 million tons capacity.

Oil refineries under construction and design at various stages of readiness

	Main products	Depth of processing, (un. units)	Planned address	Status
OOO Refinery Northern Kuzbass		90	Kemerovo region, Yaya district, pos. Treeless	Under construction
LLC "SAMARATRANSNEFT - TERMINAL"	Diesel fuel, automobile gasoline, fuel oil, sulfur.	87	Samara region, Volzhsky district, Nikolaevka village	Under construction
ZAO Naftatrans	Diesel fuel, automobile gasoline, technical sulfur.	92	Krasnodar region, Caucasus region, Art. Caucasian	Under construction
Dagnotech LLC	motor gasoline, diesel fuel, kerosene, tar, coke	73,9	Republic of Dagestan, Makhachkala, st. Airport Highway 1	Under construction
OOO VPK-Oil	Diesel fuel, automobile gasoline, jet fuel.	96	Novosibirsk region, Kochenevsky district, r.p. Kochenevo	Under construction
LLC "Belgorodsky NPZ"	motor gasoline, diesel fuel	83.8	Belgorod region, Yakovlevsky district, Builder, st. 2nd Factory, 23a	reconstructable
ECOALLIANCE M LLC	Motor gasoline, diesel fuel, heating oil, jet fuel, liquefied gases.	95	Ulyanovsk region, Novospassky district, Svirino village	projected
OOO VSP Krutogorsk Oil Refinery	Automobile gasoline, diesel fuel, fuel oil, paraffins, liquefied gases.	92	Omsk, md. Steep hill, Promploshchadka, 1	projected
OOO Tomskneftepererabotka		95	Tomsk region, Tomsk district, Semiluzhki village, Nefteprovod st., 2	projected
Itatskiy Refinery LLC	Motor gasoline, diesel fuel, fuel oil.	85	Kemerovo region, Tyazhinskiy district, town. Itatsky, st. Gorky, 1	projected
Transbunker-Vanino LLC, TRB-Vanino LLC	Aviation kerosene, diesel fuel, marine fuel, commercial sulfur, liquefied gases.	98	Khabarovsk Territory, Vanino village	projected
CJSC "SRP"	Motor gasoline, diesel fuel, fuel oil, liquefied gases.	85	188302, Leningrad region, Gatchinsky district, near the village. Small Kolpany, plot No. 1A	projected
CJSC "ToTEK"	Automobile gasoline, diesel fuel, road bitumen, sulfur, liquefied gases.	94	Tver region, Torzhoksky district, village. Churikovo	projected
CJSC Corporation ORELNEFT	Motor gasoline, jet fuel, diesel fuel, bitumen, sulfur, coke, commercial oils, liquefied gases.	97	Oryol region, Verkhovsky district, Turov s / s	projected
LLC "NPZ YuBK"	Diesel fuel, bitumen, sulfur.	98	Kemerovo region, Kemerovo district, village New Hoodie	projected
CJSC "ANTEY"	Diesel fuel, jet fuel, sulfur.	98	Republic of Adygea, Takhtamukaysky district, Yablonovsky township	projected
CJSC "VNHK"	Motor gasoline, jet fuel, diesel fuel, MTBE, sulfur, styrene, butadiene, polyethylene, polypropylene.	92	Primorsky Krai, Partizansky municipal district, Elizarova pad	projected
AEK LLC	Diesel fuel, liquefied gases, bitumen.	96	Amur region, Ivanovsky district, Berezovka village	projected
OOO ZapSib NPZ	Diesel fuel, kerosene, liquefied gases, sulfur.	95	Tomsk, Oktyabrsky district, Northern Industrial Center	projected
LLC "South Russian Refinery"	Diesel fuel, automobile gasoline, kerosene, bitumen, coke, sulfur.	98	Volgograd region, Zhirnovsky district, r.p. Krasny Yar	projected
Slavyansk ECO LLC	Diesel fuel, automobile gasoline, liquefied gases, fuel oil, marine fuel, coke, sulfur.	98	Krasnodar Territory, Slavyansk-on-Kuban, st. Kolkhoznaya, 2	projected
CJSC "Park of industrial technologies", CJSC "Park INTECH"		92	Yaroslavl region, Gavrilov-Yamsky district, village Velikoselskoe	projected
Chemical plant - a branch of JSC "Krasmash"	Diesel fuel, motor gasoline, bitumen, base oils.	94	Krasnoyarsk Territory, Zheleznogorsk, Podgorny settlement, st. Zavodskaya, d.1	projected
Siberian Barel LLC	Diesel fuel, automobile gasoline, bitumen, liquefied gases, benzene, toluene, sulfur.	96	Altai Territory, Zonal district, with. Zonal, Zapravochnaya st., 1	projected
OAO YaNPZ named after D.I. Mendeleev	Diesel fuel, motor gasoline, fuel oil, marine fuel, sulfur.	86	Yaroslavl region, Tutaevsky district, pos. Konstantinovsky	projected
CJSC Oil Refinery Kirishi 2	Diesel fuel, automobile gasoline, kerosene, liquefied gases, sulfur.	98	Leningrad region, Kirishsky district, Volkhovskoe highway, 11	projected
OAO NK "Tuymaada-neft"	Diesel fuel, motor gasoline, jet fuel, liquefied gases, bitumen.	96	Republic of Sakha (Yakutia), Aldan district, village Lebediny	projected
JSC "KNPZ"		97	Rostov region, Kamensky district, Chistoozerny village, Neftezavodskaya st., 1	projected
PNK Volga-Alliance LLC	Diesel fuel, automobile gasoline, liquefied gases, coke.	96	Samara region, Koshkinsky district, Pogruznaya station	projected
FIRST PLANT LLC	Diesel fuel, automobile gasoline, kerosene, liquefied gases, bitumen.	98	Kaluga region, Dzerzhinsky district, pos. Linen Factory	projected
LLC "NPZ Barabinsky"	Diesel fuel, motor gasoline, coke, liquefied gases, bitumen.	95	Novosibirsk region, Kuibyshevsky district, Oktyabrsky village council	projected
OOO Vtornefteprodukt	Diesel fuel, automobile gasoline, liquefied gases, sulfur.	75	Novosibirsk region, Berdsk, st. Khimzavodskaya, 11	projected
OOO PNK-Petroleum	Diesel fuel, automobile gasoline, liquefied gases, coke.	75	Stavropol Territory, Izobilnensky district, Solnechnodolsk village	projected
Yenisei Oil Refinery LLC	Diesel fuel, automobile gasoline, liquefied gases, coke.	87	Krasnoyarsk Territory, Emelyanovsky District, Shuvaevsky Village Council, 20th km. Yenisei tract (right side), section No. 38, building 1	projected
OOO Albashneft	Diesel fuel, automobile gasoline, kerosene, liquefied gases, coke.	92	Krasnodar Territory, Kanevskoy district, village Novominskaya	projected
OOO VITAND-OIL	Motor gasoline, diesel fuel, elemental sulfur	92	Leningrad region, Volosovsky district, pos. moloskovitsy	projected
EcoTON LLC	motor gasoline, diesel fuel, elemental sulfur	75	Volgograd region, Svetloyarsky district, 1.5 km south-west of the village. Light Yar	projected
Sibnefteindustriya LLC	diesel fuel, low-viscosity marine fuel, petroleum bitumen	75	Irkutsk region, Angarsk, First industrial area, quarter 17, building 11	projected
FORAS LLC	motor gasoline, diesel fuel, low-viscosity marine fuel, road bitumen, sulfur	89	Samara region, Syzran district, in the area with. Novaya Racheika, 1st Industrial Zone, plots No. 2, 4, 5, 6	projected
Oil refinery IP Dzotov F.T."	motor gasoline, diesel fuel, kerosene, coke	73,9	363712, Republic of North Ossetia - Alania, Mozdok, st. Industrial, 18	projected
CJSC "Caspian - 1"	motor gasoline, diesel fuel, fuel oil	75	Republic of Dagestan, Makhachkala, South-Eastern industrial zone, sections "A" and "B"	projected
Yurgaus LLC	motor gasoline, diesel fuel, kerosene, liquefied gases, petroleum bitumen	94	Kemerovo region, Guryev district, 1.5 km east of Guryevsk	projected

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Fundamental technological schemes Claus plants usually include three different stages: thermal, catalytic and afterburning. The catalytic stage, in turn, can also be divided into several stages that differ in temperature. The afterburner stage can be either thermal or catalytic. Each of the similar stages of Claus installations, although they have common technological functions, differ from each other both in the design of the apparatus and in the piping of communications. The main indicator that determines the scheme and mode of Claus plants is the composition of acid gases supplied for processing. The acid gas entering the Claus furnaces must contain as little hydrocarbons as possible. During combustion, hydrocarbons form tars and soot, which, when mixed with elemental sulfur, reduce its quality. In addition, these substances, deposited on the surface of the catalyst, reduce their activity. Aromatic hydrocarbons are particularly detrimental to the efficiency of the Claus process.

The water content in acid gases depends on the mode of condensation of the overhead product of the regenerator of the gas treatment plant. Acid gases, in addition to the equilibrium moisture corresponding to the pressure and temperature in the condensation unit, may also contain methanol vapor and droplet moisture. To prevent dropping liquid from entering the reactors of sulfur production units, acid gases are pre-separated.

The cost of sulfur produced at Claus plants primarily depends on the concentration of H 2 S in the acid gas.

Specific capital investments in the Claus plant increase in proportion to the decrease in the content of H 2 S in the acid gas. The cost of treating an acid gas containing 50% H 2 S is 25% higher than that required for treating a gas containing 90% H 2 S.

The gas, before being fed into the combustion chamber of the thermal stage, passes through the inlet separator C-1, where it is separated from the dropping liquid. To control the concentration of H 2 S in the acid gas, an in-line gas analyzer is installed at the outlet of the C-1 separator.

To ensure the combustion of acid gas, atmospheric air is forced into the combustion chamber using a blower, which first passes through a filter and a heater. Air is heated to eliminate impulsive combustion of acid gas and prevent corrosion of pipelines, since the combustion of H 2 S may form SO 3 , which at low temperatures in the presence of water vapor can form sulfuric acid.

The air flow is regulated depending on the amount of acid gas and the ratio of H 2 S: SO 2 in the gas at the outlet of the waste heat boiler.

The combustion gases of the reaction furnace (HR) pass through the tube bundle of the waste heat boiler, where they are cooled to 500 °C. In this case, a partial condensation of sulfur occurs. The resulting sulfur is discharged from the apparatus through the sulfur gate. Due to the partial removal of the heat of reaction by water in the boiler, steam is obtained high pressure(P=2.1 MPa).

After the boiler, the reaction gases enter the R-1 catalytic converter-reactor, where carbon disulfide and carbon sulfide undergo hydrolysis.

Due to the exothermic nature of the reactions taking place in the converter, the temperature on the catalyst surface rises by approximately 30-60°C. This prevents the formation of a liquid precipitate of sulfur, which, falling on the surface of the catalyst, would reduce its activity. Such a temperature regime in the converter also simultaneously ensures the decomposition of the products of side reactions - COS and CS 2 .

The main part of the gas (about 90%) from the reactor enters the tube space of the X-1 condenser for cooling, and then goes to the R-2 reactor. Heat removal in the X-1 condenser is carried out due to the evaporation of water in its annulus to obtain low-pressure steam (P=0.4 MPa). When gases are cooled in X-1, sulfur condenses. Liquid sulfur is discharged through the sulfur gate to the degassing unit.

Part of the reaction gases (about 10%), bypassing the X-1 condenser, enters for mixing with colder gases leaving the same condenser. The temperature of the mixture before entering the R-1 reactor is about 225°C.

To control the temperature in the R-1, R-2, R-3 reactors (during the start-up period and in the event of a sulfur fire), low-pressure steam and nitrogen are supplied to them.

At normal operation the temperature of the gases at the outlet of X-2 and R-1 is 191 and 312°C, respectively.

Removal of heat in the apparatus X-2 is carried out due to the evaporation of water in its annulus to obtain low-pressure steam.

Exhaust gases from the R-2 reactor are fed to the third condenser X-3 for cooling, from where they are fed at a temperature of 130°C for post-treatment.

To control the concentration of H 2 S and SO 2 in the exhaust gases, flow gas analyzers are installed at the outlet of X-3.

To prevent the entrainment of liquid sulfur with exhaust gases, a coalescer is installed on their lines.

To prevent solidification of sulfur in the coagulator, periodic supply of water vapor is provided.

The streams of liquid sulfur discharged from the condensers contain 0.02-0.03% (wt.) hydrogen sulfide. After the degassing of sulfur, the concentration of H 2 S in it decreases to 0.0001%.

Sulfur degassing is carried out in a special block - a sulfur pit. This provides normal conditions for warehousing, loading and storage of gas sulfur.

The main amount (~98%) of acid gas is fed into the reactor-generator, which is a gas-tube type steam boiler. Process gas - products of combustion - sequentially passes through the pipe part of the boiler and the condenser-generator, where it is cooled down to 350 and 185°C, respectively.

At the same time, due to the heat released in these devices, water vapor is formed with a pressure of 2.2 and 0.48 MPa, respectively.

The degree of conversion of H2S to sulfur in the reactor-generator is 58-63%. Further conversion of sulfur compounds into elemental sulfur is carried out in catalytic converters.

Table 1.1 - Compositions of the flows of the Claus installation,% (vol.):

Table 1.2 - Duration of residence (f S) of the process gas in the apparatus at various expenses acid gas G:

In table. 1.1 and 1.2 show the results of a survey of the operation of the installation.

The degree of conversion of H2S to sulfur in the furnace of the reactor-generator is 58-63.8, in the first and second converters 64-74 and 43%, respectively. After the last stage of sulfur condensation process gases enter the afterburner.

At a gas flow rate of 43-61 thousand m3/h, the afterburner provided almost complete oxidation of H 2 S to SO 2 . With a long residence time of the gas in the furnace, the complete conversion of H 2 S to SO 2 is not ensured: at the outlet of the furnace, the concentration of H 2 S in the gas was 0.018-0.033%.

The main indicators of gas sulfur must meet the requirements of GOST 126-76.

At present, dozens of modified variants of the Claus installation schemes have been developed. The scope of these schemes depends both on the content of hydrogen sulfide in acid gases, and on the presence of various impurities in them, which have a negative impact on the operation of sulfur production units.

For gases with a low sulfur content (from 5 to 20%), four options for improved Claus plants were analyzed.

The first option provides for the supply of oxygen to the combustion chamber (CC) of the furnace instead of air according to the standard scheme. To obtain stable flames, as the H2S content in the feed gas decreases, an acid gas stream is introduced into the combustion chamber, bypassing the burners. The flow jets provide good mixing of the combusted gases with the gas supplied to the system, bypassing the burners. Furnace dimensions and flow rates are chosen to provide sufficient contact time for interaction between the components of both gas streams. After the combustion chamber, the further course of the process is similar to the conventional Claus process.

In the second variant, the feed gas is preheated before being fed to combustion due to the partial heat recovery of the gas flow leaving the combustion chamber. In case of insufficient preheating to obtain the required temperature in the combustion chamber, fuel gas is supplied to it.

The third option involves burning sulfur. Part of the feed gas flow is fed into the combustion chamber, pre-mixed with air. The rest of the acid gas is introduced into the combustion chamber in separate jets through bypass lines. To maintain the required temperature and stabilize the process in the combustion chamber, the resulting liquid sulfur is additionally burned in a special burner mounted in the combustor.

If there is insufficient heat in the system, the required amount of fuel gas is supplied to the CS.

In the fourth option, unlike the previous options, the process does not require a combustion chamber: the sour gas is heated in a furnace and then fed into the converter. The sulfur dioxide required for the catalytic conversion is obtained in the sulfur combustion chamber, where air is supplied to ensure the combustion process. Sulfur dioxide from the CS passes through the waste heat boiler, then mixes with heated acid gas and enters the catalytic converter.

Analysis of these tables allows us to draw the following conclusions:

• - the use of a process with preheating of the feed gas is preferable at a high cost of oxygen;
• - the use of the oxygen process is beneficial when the price of oxygen is less than 0.1 grades 1 m 3 .

At the same time, the cost of sulfur is also favorably affected by relatively low concentrations of H2S in acid gas;

• - in terms of the cost of sulfur, the best performance has a catalytic process with the production of sulfur dioxide from sulfur;
• - the most expensive is the process of burning sulfur. This process can be used in the complete absence of hydrocarbons in the feed gas, since the presence of hydrocarbons in the gas causes the formation and deposition of carbon and tar on the catalyst, reducing the quality of sulfur.

Figure 1.4 - Influence of the price of oxygen y on the cost of sulfur CS at different concentrations of H2S in the gas:

Table 1.3 - Average indicators of options for processing sweet gas at the Claus plant:

It is possible to improve the Claus process due to two-stage conversion of H 2 S into elemental sulfur: part of the gas is supplied to the reactor according to the usual scheme, and the other part, bypassing the reaction furnace, is fed to the second conversion stage.

According to this scheme, it is possible to process acid gases with a hydrogen sulfide concentration of less than 50% (vol.). The lower the content of H 2 S in the raw material, the most of it, bypassing the reaction chamber, is fed into the converter stage.

However, one should not get carried away by bypassing a large volume of gas. The greater the amount of bypassed gas, the higher the temperature in the converter, which leads to an increase in the amount of nitrogen oxides and tri - sulfur oxide in the combustion products. The latter, upon hydrolysis, forms sulfuric acid, which reduces the activity of the catalyst due to its sulfation. The amount of nitrogen oxide and SO3 in gases especially increases at temperatures above 1350°C. VNIIGAZ has also developed a technology for producing polymeric sulfur. Polymeric sulfur differs from conventional sulfur modifications in its high molecular weight. In addition, unlike ordinary sulfur, it does not dissolve in carbon disulfide. The latter property serves as the basis for determining the composition of polymeric sulfur, the quality requirements for which are given in Table 1.4. Polymeric sulfur is mainly used in the tire industry.

Sulfur is an inevitable by-product of hydrocarbon processing, which can bring both profit and problems due to its environmental unsafety. At the Moscow Oil Refinery, these problems were solved by modernizing the sulfur production unit, which had a positive impact on the economic component of the process.

Sulfur is a common chemical element and is found in many minerals, including oil and natural gas. During the processing of hydrocarbon raw materials, sulfur becomes a by-product that needs to be disposed of in some way, and ideally made a source of additional profit. A factor complicating the situation is the non-environmental friendliness of this substance, which requires special conditions for its storage and transportation.

On a global market scale, the volumes of sulfur produced in the processing of oil and gas are approximately equal and in total account for about 65%. Almost 30% more is accounted for by off-gases from non-ferrous metallurgy. A small remaining share is the direct development of sulfur deposits and the extraction of pyrites*. In 2014, the world produced 56 million tons of sulfur, while experts predict an increase in this figure by 2017-2018 due to the commissioning of new large gas fields in Central Asia and the Middle East.

The Russian sulfur market can be considered to be significantly monopolized: approximately 85% of raw materials are supplied by gas processing enterprises of Gazprom. The remaining share is divided between Norilsk Nickel and oil refining. According to Rosstat, in 2015 Russia produced about 6 million tons of sulfur, which allows the country to occupy a tenth of the world market. The domestic market is surplus: Russian consumers (and these are mainly fertilizer producers) annually buy about 2-3 million tons of sulfur, the rest is exported. At the same time, the consumer market can also be considered a monopoly: about 80% of all liquid sulfur produced in Russia is purchased by enterprises of the PhosAgro group, and approximately 13% is sent to another producer of mineral fertilizers - EuroChem. Only granulated and lump sulfur is exported (see inset on types of sulfur).

Types of commercial sulfur

Simple sulfur is a light yellow powdery substance. In nature, sulfur can occur both in native crystalline form and in various compounds, including natural gas and oil. Currently, three forms of sulfur are mainly produced - lumpy, liquid and granulated. When sulfur is released from gases, liquid (or molten) sulfur is obtained. It is stored and transported in heated tanks. For the consumer, the transport of liquid sulfur is more profitable than its melting on site. The advantages of liquid sulfur are the absence of losses during transportation and storage and high purity. Disadvantages - risk of fire, spending on heating tanks.

When liquid sulfur is cooled, lump sulfur is obtained. It was it that until the early 1970s was mainly produced in the USSR. Among the disadvantages of lump sulfur: low quality, losses to dust and crumbs during loosening and loading, fire hazard, low environmental friendliness.

Granular sulfur is obtained directly from liquid sulfur. Various ways granulation is reduced to breaking the liquid into separate drops with their subsequent cooling and encapsulation.

Obviously, large consumers are interested in a supplier that can fully satisfy their demand. “In this situation, small producers, as a rule, are looking for buyers among neighboring enterprises - this allows them to save on logistics and thereby increase interest in the product,” explained Zakhar Bondarenko, Head of the Petrochemistry and LPG Department of Gazprom Neft. “Sometimes sulfur, being a by-product of production, is sold for nothing at all, just to get rid of raw materials that are unsafe for storage.”

Choosing its strategy for the utilization of hydrogen sulfide, the Moscow Oil Refinery relied on the environment, but was able to take into account financial interests as well.

Odorless and dust free

The reconstruction of the sulfur production unit at the Moscow Refinery became part of a comprehensive modernization project aimed at improving the plant's environmental performance. In 2014, the Moscow Refinery switched to the production of granulated sulfur, a modern product that meets the most stringent environmental requirements. As part of the reconstruction, the equipment of the plant was updated, a granulation unit and an off-gas aftertreatment unit were built.

Significant volumes of hydrogen sulfide-containing (acid) gases at refineries are obtained as a result of the catalytic cracking process, as well as the hydrotreatment of gasoline and diesel fuel from sulfur originally contained in oil. Today, this problem is especially relevant: oil is becoming more and more sulphurous, and environmental standards for fuel severely limit the content of this element. Environmental class Euro-5, which corresponds to all gasoline produced at the Moscow Refinery, implies a five-fold reduction in the sulfur content in the fuel compared to Euro-4, from 50 to 10 mg / kg.

Yuri Erokhin,
head of labor protection department, industrial safety and protection environment MNPZ

For oil refineries, a sulfur recovery unit is primarily an air-protective facility that allows hydrogen sulfide to be utilized without harming the environment. After implementation at Moscow Refinery modern technologies we were able to completely eliminate hydrogen sulfide emissions into the atmosphere. This is not an unfounded assertion. Zero emissions are also confirmed by instrumental control, which we regularly carry out in accordance with the law by an independent accredited laboratory. In fact, the reconstruction of the sulfur recovery unit made it possible to reduce emissions at the Moscow Refinery by 50%. This is a significant achievement not only for the plant, but for the ecology of the entire region. At the same time, by switching to the production of granulated sulfur and moving away from the production of lump sulfur, we were able to improve the environmental situation directly on the territory of the plant.

At the sulfur recovery unit, hydrogen sulfide is first oxidized to sulfur dioxide, which is then converted into elemental sulfur by interaction with the same hydrogen sulfide in the presence of a catalyst (Clauss process). However, in order to completely utilize hydrogen sulfide, it is necessary not only to drive acid gases through the installation, but also to carry out subsequent additional purification. “In the process of upgrading the unit, we changed 90% of the equipment,” said Vladimir Suvorkin, curator of the sulfur recovery unit. - But one of the main stages of the project was the construction of an after-treatment unit for off-gases. The new post-treatment unit allows minimizing sulfur dioxide emissions and returning all hydrogen sulfide to the process. Thus, we managed to increase the sulfur recovery by more than 20% - now it reaches 90%. At the same time, hydrogen sulfide emissions are completely eliminated.”

Another important environmental aspect is getting rid of lump sulfur - bulk material, the storage of which is inevitably associated with the formation of a large amount of harmful dust. Initially, the plant produces liquid sulfur, which can either be sold in liquid form, or cooled and turned into lumps, or granulated. “There were two sulfur pits with a volume of 50 tons each for storing liquid sulfur at the old plant,” said Vladimir Suvorkin. - When there was no shipment of liquid sulfur, it was necessary to pump sulfur to the warehouse in railway or tank trucks and store it already in a crystallized lumpy form. With the commissioning of a new unit (sulfur pit) with a volume of 950 tons, we got rid of this problem.” Part of the liquid sulfur is now sold to one of the enterprises located in the Moscow region, the rest is sent to the granulation unit.

Structure of sulfur consumption in Russia

Commodity structure of sulfur production in Russia
in 2009-2015, %

Source: Infomine

The structure of the sulfur market in the Russian Federation,
million tons

In contrast to the production of lump sulfur, granulation produces practically no dust and odor. Each granule is a hemisphere with a size of 2 to 5 mm and is in a polymer shell, which prevents its dissolution. At the exit from the conveyor, the finished products are packaged in modern packaging - hermetic bags "big bags". Such packaging completely eliminates the contact of sulfur with the environment.

Transport node

Of course, sulfur granulation is a rather complicated and costly process, which significantly increases the cost of the product. Gazprom Neft could avoid the cost of commissioning additional equipment if all liquid sulfur it produces is sold on the market. However, this is not to be expected. the main problem Russian market of this product today is the shortage of tanks associated with the new technical regulations obliging the owners of rolling stock to either modernize obsolete rolling stock or decommission it. Tank car owners prefer the second option, while no one is in a hurry to invest in the production of new tanks. "On the scale domestic market sulfur refinery is a small producer, so it makes no sense for the company to spend money on expanding its own fleet of tanks, - said Zakhar Bondarenko. “It turned out to be much more profitable to granulate unsold liquid sulfur residues and sell them to foreign markets, where you can always find a buyer even for small volumes.”

Sulfur Recovery Unit

The modernized sulfur production unit at the Moscow Refinery includes two sulfur recovery units, each of which has been reconstructed. The depth of sulfur recovery in these blocks reaches 96.6%. Also, the unit is equipped with an aftertreatment unit for off-gases, which ultimately makes it possible to recover 99.9% of sulfur. Up to 950 tons of liquid sulfur can be simultaneously stored in the new sulfur loading unit, which completely eliminates the need for the production and storage of lump sulfur. In addition, a sulfur granulation unit was put into operation. The design capacity of the plant for liquid degassed sulfur, taking into account the operation of the off-gas treatment unit, is 94 thousand tons per year, and the design capacity of the liquid sulfur granulation unit is 84 thousand tons per year, which fully covers the existing needs of the enterprise for the utilization of hydrogen sulfide gases.

If granulated sulfur turns out to be too expensive for Russian consumers, the processing of which, moreover, requires additional equipment, then foreign markets demand for granulated sulfur is consistently high. Today, granulated sulfur from the Moscow Refinery is supplied to more than a dozen countries, including countries in Latin America, Africa and Southeast Asia. “Currently, granulated sulfur on the world market is gradually replacing its other commodity forms thanks to more high quality(absence of impurities and pollution) and ease of transportation, - explained Olga Voloshina, head of the chemical products markets department of the Infomine research group. - At the same time domestic market traditionally use mainly liquid sulfur. In the near future, this situation is unlikely to change, since in order to switch production to the use of granulated sulfur instead of liquid, it is necessary to re-equip them, including the creation of sulfur smelting facilities. This will require additional costs, which few people will pay in the conditions of the economic crisis.”

Prospects and opportunities

Despite the current demand for sulfur in foreign markets, experts are very cautious in forecasting the development of this area. The world market is highly dependent on the largest importers, primarily China, which in 2015 imported about 10 million tons of sulfur. However, development own production gradually reduces the interest of the Chinese in imports. The situation with other significant players is also unstable. In this regard, for several years in a row, Gazprom, as the largest exporter, has been talking about the need to look for alternative markets for sulfur within the country. The sphere of road construction could become such a market, subject to the active introduction of new materials - sulfur asphalt and sulfur concrete. Comparative studies of these materials show a number of their advantages, in particular, environmental safety, wear resistance, heat resistance, crack resistance, resistance to rutting. “Despite the creation of experimental batches paving slabs from sulfur concrete, as well as covering road sections with sulfur asphalt, mass industrial production these building materials until it was adjusted, - Olga Voloshina stated. “The developers explain this by the lack of a regulatory and technical base that regulates the requirements for this type of materials, as well as for pavement construction technologies.”

While Gazprom is working on a long-term target program creation and development in the Russian Federation of a sub-sector of the industry of building and road-building materials based on sulfur binder. At one time, the company spoke about the expediency of locating the production of such materials in regions with a high level of road construction and the availability of raw materials. Then, the Moscow Oil Refinery was called as a potential raw material and production base. True, so far there are no such projects in Gazprom Neft.

4.1 Installation of ELOU-AVT

The unit is designed to clean oil from moisture and salts, and for the primary distillation of oil into fractions used as raw materials for further processing. In table. 4.1. and 4.2. the material balances of the ELOU and AVT blocks are given, respectively.

The plant consists of three blocks: 1. Demineralization and dehydration. 2. Atmospheric distillation. 3. Vacuum distillation of fuel oil.

The raw material of the process is oil.

Products: Gas, Fractions 28-70 o C, 70-120 o C, 120-180 o C, 180-230 o C, 230-280 o C, 280-350 o C, 350-500 o C, and fraction, boiling over at temperatures above 500 o C.

Table 4.1

Material balance of the ELOU block

Table 4.2

Material balance of the AVT installation

balance sheet items	potential content,	Selection from potential in fractions of unity	actual selection,
				thousand tons/year
received:
Fraction 28-70 °C
Fraction 85-120 °C
Fraction 120-180 °C
Fraction 180-230 °C
Fraction 230-280 °С
Fraction 280-350 °С
Fraction 350-485 °C
Fraction >485 °C

4.2 Catalytic reforming

At the planned refinery, the catalytic reforming process is designed to improve the knock resistance of gasoline.

As a feedstock for reforming, we use a wide straight-run gasoline fraction 70 - 180 ºС from the CDU-AVT unit, as well as visbreaking, coking gasolines and hydrotreated stripping gasolines.

The mode of catalytic reforming installations depends on the type of catalyst, the purpose of the installation, and the type of feedstock. In table. Table 4.3 shows the performance of a selected UOP CCR ​​platform catalytic reformer with continuous catalyst regeneration.

Table 4.3

Technological mode of the installation of catalytic reforming fr. 70 - 180 °С

These installations are more economical in reducing the operating pressure while increasing the depth of conversion of raw materials. Moving bed reforming is the most modern industrial process model and provides consistently high gasoline yield and octane number, as well as maximum hydrogen yield at low process severity.

We will use the Axens HR-526 catalyst at the reformer. The catalyst is chlorine-promoted alumina with platinum (0.23% wt.) and rhenium (0.3% wt.) evenly distributed throughout the volume. The catalyst beads have a diameter of 1.6 mm and a specific surface area of ​​250 m 2 /g.

To ensure a long-term operation cycle of this catalyst, the feedstock must be purified from sulfur, nitrogen and oxygen-containing compounds, which is ensured by the inclusion of a hydrotreatment unit in the reformer.

The products of the catalytic reformer are:

Hydrocarbon gas - contains mainly methane and ethane, serves as fuel for oil refinery furnaces;

Stabilization head (hydrocarbons C 3 - C 4 and C 3 - C 5) - are used as raw materials for HFCs of saturated gases;

The catalyzate, the output of which is 84% ​​wt. used as a component of motor gasolines. It contains 55 - 58% wt. aromatic hydrocarbons and has an octane number (OM) = 100 points;

4.3 Hydrotreating

The process is designed to provide the necessary level of performance characteristics of light distillates, catalytic cracking feedstock, which today is determined mainly by environmental requirements. The quality of hydrotreating products is improved as a result of the use of destructive hydrogenation reactions of sulfur, nitrogen and oxygen-containing compounds and hydrogenation of unsaturated hydrocarbons.

We send a fraction of diesel fuel to the hydrotreatment unit, which boils away in the range of 180 - 350 ºС. The composition of the feedstock of the diesel fuel hydrotreater also includes light coking gas oil. Based on the data in Table. 1.6, the sulfur content in this fraction is taken equal to 0.23% wt. as in the fraction 200 - 350ºС.

The main parameters of the technological regime of the diesel fuel hydrotreater are presented in Table. 4.4.

Table 4.4

Technological mode of the diesel fuel hydrotreater

In world practice, aluminum-cobalt-molybdenum (ACM) and aluminum-nickel-molybdenum (ANM) are most widely used in hydrogenation processes. AKM and ANM hydrotreatment catalysts contain 2–4 wt %. Co or Ni and 9 - 15% wt. MoO 3 on active γ-alumina. At the stage of start-up operations or at the beginning of the raw cycle, they are subjected to sulfidation (sulfurization) in a stream of H 2 S and H 2 , while their catalytic activity increases significantly. In our project, at the diesel fuel hydrotreatment unit, we will use a domestic catalyst of the GS-168sh brand, with the following characteristic:

bulk density ÷ 750 kg/m 3 ;

carrier ÷ aluminosilicate;

granule diameter ÷ 3 – 5 mm;

interregeneration period ÷ 22 months;

total service life ÷36 – 48 months.

The plant's products are:

hydrotreated diesel fuel;

distilled gasoline - used as a raw material for a catalytic reformer, has a low (50 - 55) octane number;

hydrogen sulfide - is sent as raw material to the elemental sulfur production unit;

fuel gas.

The guidelines suggest that 100% of the diesel hydrotreater feedstock has the following yield:

hydrotreated diesel fuel - 97.1% wt;

distilled gasoline - 1.1% wt.

The output of hydrogen sulfide in % wt. on raw materials is determined by the formula

x i is the yield of hydrotreated products in fractions of a unit;

32 is the atomic mass of sulfur.

Fraction 230-350 o C contains sulfur 0.98% wt. The composition of the feedstock of the diesel fuel hydrotreater also includes light coking gas oil. The sulfur content in environmentally friendly diesel fuel is 0.01% wt.

Products output:

H 2 S \u003d 0.98-(0.01 * 0.971 + 0.01 * 0.011) * 34/32 \u003d 0.97%

4.4 Gas fractionation plant (HFC)

The unit is designed to produce individual light hydrocarbons or high purity hydrocarbon fractions from refinery gases.

Gas fractionation plants are subdivided according to the type of processed raw materials into HFCs of saturated and HFCs of unsaturated gases.

The raw material for HFCs of saturated gases is gas and the AVT stabilization head mixed with the stabilization heads for the catalytic reforming of the gasoline fraction and hydrocracking of vacuum gas oil.

In table. 4.5 shows the process mode of HFC saturated gases.

Table 4.5

Technological mode of HFC distillation columns of saturated gases

distillation columns	Shared Components	Bottom temperature, °С	Top temperature, °С	Pressure, MPa
K-1 (deethanizer)	C 2 H 6 / C 3 H 8 +
K-2 (propane)	C 3 H 8 / ΣC 4 H 10 +
K-3 (butane)	ΣC 4 H 10 / ΣC 5 H 12 +
K-4 (isobutane)	iso- C 4 H 10 / n- C 4 H 10
K-5 (pentane)	ΣC 5 H 12 / C 6 H 14 +
K-6 (isopentane)	iso- C 5 H 12 / n- C 5 H 12

HFC products of saturated gases - narrow hydrocarbon fractions:

ethane - used as a raw material for the production of hydrogen, as well as a fuel for process furnaces;

propane - used as a raw material for pyrolysis, household liquefied gas, refrigerant;

isobutane - serves as a raw material for alkylation plants and the production of synthetic rubber;

butane - used as household liquefied gas, raw material for the production of synthetic rubber, in winter time added to commercial motor gasoline to provide the required saturated vapor pressure;

isopentane - used as a component of high-octane gasolines;

pentane - is a raw material for catalytic isomerization processes.

When separating unsaturated hydrocarbon gases, AGFU units (absorption-gas fractionation unit) are used. Their distinguishing feature is the use of technology for the absorption of hydrocarbons C 3 and higher by a heavier hydrocarbon component (fractions C 5 +) for the separation of dry gas (C 1 - C 2) in column K-1. The use of this technology makes it possible to reduce the temperatures in the columns and thereby reduce the likelihood of polymerization of unsaturated hydrocarbons. The raw materials of AGFU of unsaturated gases are gases of secondary processes, namely: catalytic cracking, visbreaking and coking.

The main parameters of the technological mode of the AGFU installation of unsaturated gases are presented in Table. 4.6.

Table 4.6

Technological mode of distillation columns AGFU of unsaturated gases

distillation columns	Shared Components	Bottom temperature, °С	Supply temperature, °С	Top temperature, °С	Pressure, MPa
K-1 (fractionating absorber)	C 2 - / ΣC 3 +
K-2 (stabilization column)	ΣC 3 - ΣС 5 / ΣC 6 +
K-3 (propane)	ΣC 3 / ΣC 4 +
K-4 (butane)	ΣC 4 / ΣС 5 +

The products of processing of unsaturated hydrocarbon raw materials are the following fractions:

propane-propylene - used as a raw material for polymerization and alkylation plants, production of petrochemical products;

butane-butylene - is used as a feedstock for the alkylation unit in order to produce alkylate (a high-octane component of commercial motor gasoline).

4.5 Catalytic isomerization of light gasoline fractions

The catalytic isomerization unit is designed to increase the octane number of light gasoline fraction 28 - 70ºС of the gasoline secondary distillation unit by converting paraffins of normal structure into their isomers with higher octane numbers.

There are several variants of the process of catalytic isomerization of paraffinic hydrocarbons. Their differences are due to the properties of the catalysts used, the process conditions, as well as the adopted technological scheme (“per pass” or with the recycle of unconverted normal hydrocarbons).

The isomerization of paraffinic hydrocarbons is accompanied by side reactions of cracking and disproportionation. To suppress these reactions and maintain the activity of the catalyst at a constant level, the process is carried out at hydrogen pressures of 2.0–4.0 MPa and circulation of a hydrogen-containing gas.

The projected refinery uses a low-temperature isomerization process. The parameters of the technological mode of fraction isomerization 28 - 70ºС are given in Table. 4.7.

Table 4.7

Technological mode of the catalytic

isomerization of light gasoline fraction

During the isomerization process n- alkanes, modern bifunctional catalysts are used, in which platinum and palladium are used as a metal component, and fluorinated or chlorinated aluminum oxide as a carrier, as well as aluminosilicates or zeolites introduced into the aluminum oxide matrix.

It is proposed to use a low-temperature isomerization catalyst based on sulfated zirconia CI-2 containing platinum 0.3-0.4 wt. % deposited on alumina.

The main product of the unit is isomerizate (OCM 82 - 83 points), used as a high-octane component of motor gasoline, responsible for its starting characteristics.

Together with the isomerizate, dry saturated gas is obtained in the process, which is used at the plant as a fuel and raw material for hydrogen production.

4.6 Bitumen production

This unit at the projected refinery is designed to produce road and construction bitumen.

The raw material of the bitumen production plant is the residue of vacuum distillation of fuel oil (tar).

For the production of bitumen, the following methods are used:

deep vacuum distillation (obtaining residual raw materials);

oxidation of petroleum products with air at high temperature (obtaining oxidized bitumen);

compounding of residual and oxidized bitumen.

Table 4.8.

Table 4.8

Technological mode of the bitumen production unit with an oxidizing column

road bitumens used in road construction for the preparation of asphalt concrete mixtures;

construction bitumen used in the performance of various construction works, in particular for waterproofing the foundations of buildings.

4.7 Catalytic cracking with hydrotreating

The process of catalytic cracking is one of the most common large-scale processes of deep oil refining and to a large extent determines the technical and economic indicators of modern and prospective oil refineries.

The process is designed to obtain additional quantities of light oil products - high-octane gasoline and diesel fuel - by decomposition of heavy oil fractions in the presence of a catalyst.

As a raw material for the plant at the projected refinery, vacuum gas oil of direct distillation of oil (fraction 350 - 500ºС) after preliminary upgrading is used, which is used as a catalytic hydrotreatment from harmful impurities - sulfur, nitrogen and metals.

The catalytic cracking process is planned to be carried out on a domestic cracking unit with a G-43-107 riser reactor on a microspherical zeolite-containing catalyst.

The main factors influencing the process of catalytic cracking are: the properties of the catalyst, the quality of the feedstock, the temperature, the duration of contact between the feedstock and the catalyst, the catalyst circulation rate.

The temperature in this process is the regulator of the depth of the catalytic cracking process. As the temperature rises, the yield of gas increases, and the amount of all other products decreases. At the same time, the quality of gasoline is slightly improved due to aromatization.

The pressure in the reactor-regenerator system is maintained almost constant. An increase in pressure somewhat worsens the selectivity of cracking and leads to an increase in gas and coke formation.

In table. 4.9 shows the indicators of the technological mode of the catalytic cracking unit with a riser reactor.

Table 4.9

Technological mode of the catalytic cracking unit

Process conditions	established norm
Temperature, ºС
in the reactor
in the regenerator
Pressure, MPa
in the reactor
in the regenerator
Mass feed rate of raw materials, h -1
Catalyst circulation rate

Catalysts of modern catalytic cracking processes carried out at high temperatures are complex multicomponent systems consisting of a matrix (carrier), an active component - zeolite, and auxiliary active and inactive additives. Synthetic amorphous aluminosilicate with a high specific surface area and optimal pore structure is mainly used as a matrix material for modern catalysts. Usually, in industrial amorphous aluminosilicates, the content of aluminum oxide is in the range of 6–30% wt. The active component of cracking catalysts is a zeolite, which is an aluminosilicate with a three-dimensional crystal structure of the following general formula

Me 2 / n O Al 2 O 3 x SiO 2 at H 2 O,

which allows to carry out secondary catalytic transformations of raw hydrocarbons with the formation of final target products. Auxiliary additives improve or impart some specific physicochemical and mechanical properties to zeolite-containing aluminosilicate catalysts (CSC) for cracking. As promoters that intensify the regeneration of a coked catalyst, platinum applied in low concentrations (<0,1 %мас.) непосредственно на ЦСК или на окись алюминия с использованием как самостоятельной добавки к ЦСК.

At the catalytic cracking unit, we will use a domestic catalyst of the KMTs-99 brand, with the following characteristic:

gasoline yield ÷ 52 - 52.5% wt.;

octane number (IM) ÷ 92;

catalyst consumption ÷ 0.4 kg/t of raw material;

average particle size ÷ 72 microns;

bulk density ÷ 720 kg/m 3 .

The products of the catalytic cracking unit are:

In this project, the feedstock of the catalytic cracking unit is a part of the straight-run oil fraction 350 - 500 ° C with a sulfur content of 1.50% wt.

To calculate the yield of hydrogen sulfide in the process of hydrotreating vacuum gas oil, we take the sulfur content in the products and the yield of products as follows:

hydrotreated vacuum gas oil - 94.8% wt;

distilled gasoline - 1.46% wt.

Hydrotreating products also include: fuel gas, hydrogen sulfide and losses.

where S 0 – sulfur content in the feedstock, wt %;

S i– sulfur content in the end products of the process, wt %;

X i is the yield of hydrotreated products in fractions of a unit;

34 – molecular weight of hydrogen sulfide;

32 is the atomic mass of sulfur.

H 2 S \u003d (1.50– (0.2 * 0.948 + 0.2 * 0.014) * 34/32 \u003d 1.26%

4.8 Coking

The unit is designed to produce petroleum coke, to produce additional amounts of light oil products from heavy oil residues.

The raw material of the coking unit is a part of the tar (residue of the vacuum distillation of fuel oil) with a coking capacity of 9.50% wt. and a sulfur content of 0.76% wt.

At the projected refinery, the coking process will be carried out at a delayed (semi-continuous) coking unit (DCU).

In table. 4.10 shows the technological mode of the ultrasonic testing unit.

Table 4.10

Technological mode of the ultrasonic testing unit

The products of the plant are:

petroleum coke - used in the production of anodes for aluminum smelting and graphite electrodes, for the production of electrolytic steel, used in the production of ferroalloys, calcium carbide;

gas and stabilization head - contains mainly unsaturated hydrocarbons and is used as a raw material for HFCs of unsaturated hydrocarbons;

gasoline - contains up to 60% of unsaturated hydrocarbons, is not chemically stable enough, RONM = 60 - 66 points, after deep hydrotreating it is used as a feedstock for a catalytic reformer;

light gas oil - serves as a component of diesel fuel;

heavy gas oil is a component of boiler fuel.

4.9 Visbreaking

The unit is designed to reduce the viscosity of heavy oil residues in order to obtain a component of stable boiler fuel.

The raw material for visbreaking is tar (fraction > 500 °C) from the vacuum unit of the CDU-AVT unit.

At the projected refinery, we use a visbreaking unit with an external reaction chamber. In visbreaking of this direction, the required degree of raw material conversion is achieved at a milder temperature regime (430–450 °C), a pressure of no more than 3.5 MPa, and a long residence time (10–15 min).

The products of the plant are:

gas - used as fuel gas;

gasoline - characteristic: OCMM = 66 - 72 points, sulfur content - 0.5 - 1.2% wt, contains many unsaturated hydrocarbons. Used as reforming feedstock;

cracked residue - used as a component of boiler fuel, has a higher calorific value, lower pour point and viscosity than straight-run fuel oil.

4.10 Alkylation

The purpose of the process is to obtain gasoline fractions with high stability and knock resistance using the reaction of isobutane with olefins in the presence of a catalyst.

The feedstock of the plant is isobutane and butate-butylene fraction from the HFC unit of unsaturated gases.

The alkylation process is the addition of butylene to paraffin to form the corresponding higher molecular weight hydrocarbon.

At the projected refinery, we use a sulfuric acid alkylation unit. Thermodynamically, alkylation is a low-temperature reaction. The temperature limits of industrial sulfuric acid alkylation are from 0°С to 10°С, since at temperatures above 10–15 °С, sulfuric acid begins to intensively oxidize hydrocarbons.

The pressure in the reactor is chosen in such a way that all hydrocarbon feedstock or its main part is in the liquid phase. The pressure in industrial reactors is on average 0.3 - 1.2 MPa.

Sulfuric acid is used as an alkylation catalyst. The choice of this substance is due to its good selectivity, ease of handling liquid catalyst, relative cheapness, long cycles of plant operation due to the possibility of regeneration or continuous replenishment of catalyst activity. For alkylation of isobutane with butylenes, we use 96 - 98% H 2 SO 4 . The products of the plant are:

4.11 Sulfur production

Hydrogen sulfide, released from process gases of thermohydrocatalytic processes for processing a given oil, is used at refineries for the production of elemental sulfur. The most common and efficient industrial method for producing sulfur is the Claus catalytic oxidative conversion of hydrogen sulfide.

The Claus process is carried out in two stages:

stage of thermal oxidation of hydrogen sulfide to sulfur dioxide in the reactor furnace

stage of catalytic conversion of hydrogen sulfide and sulfur dioxide in the R-1 and R-2 reactors

The technological mode of the installation is presented in table. 4.12.

Table 4.12

Technological mode of the sulfur production unit

Process conditions	established norm
Overpressure, MPa
Temperature, ºС
in the reactor furnace
at the outlet of waste heat boilers
at the entrance to the R-1 reactor
at the outlet of the R-1 reactor
at the R-2 reactor inlet
at the outlet of the R-1 reactor

We use active aluminum oxide as a catalyst, the average service life of which is 4 years.

Sulfur is widely used in the national economy - in the production of sulfuric acid, dyes, matches, as a vulcanizing agent in the rubber industry, etc.

4.12 Hydrogen production

The widespread introduction of hydrogenation and hydrocatalytic processes at the proposed refinery requires a large amount of hydrogen, in addition to that supplied from the catalytic reformer.

The hydrogen balance for the projected refinery with deep processing of Teplovskaya oil is presented in Table. 4.13.

Table 4.13

Hydrogen balance for refineries with deep

processing of Teplovskaya oil of the coal-bearing horizon.

For the production of hydrogen, we use, as the most cost-effective method, the method of steam catalytic conversion of gas raw materials.

The interaction of methane (or its homologues) with water vapor proceeds according to the equations

Table 4.14

Distribution of straight-run fractions of Teplovskaya oil by technological processes, % wt.

Name	Actual selection, % wt. for oil			catalytic isomerization	Catalytic reforming to obtain high octane gasoline		Hydrotreatment of diesel fuel	catalytic cracking	Delayed coking	Visbreaking	Bitumen production
Oil fractions:
gas + reflux
Fraction 28-70 °C
Fraction 70-120 °С
Fraction 120-180 °C
Fraction 180-230 °C
Fraction 230-280 °С
Fraction 280-350 °С
Fraction 350-500 °С
Fraction over 500 °С
Productivity for straight-run raw materials, thousand tons in year

SCHEME OF REFINERY