RU2320699C1 - Method and apparatus for thermal processing of high-ash and low-grade solid fuels - Google Patents

Abstract

FIELD: thermal processing of low-grade solid fuels such as blacks and brown coal.

SUBSTANCE: method involves grinding low-grade solid fuels; drying; providing pyrolysis using solid heat-carrier in conjunction with hydrocarbon wastes to produce gaseous-vapor mixture and solid hydrocarbon residue; purifying and condensing gaseous-vapor mixture to produce valuable liquid and gaseous products; burning solid hydrocarbon residue to produce mixture of solid heat-carrier with combustion gases; separating combustion gases from solid heat-carrier. Hydrocarbon wastes are liquid hydrocarbons, bitumen, gas-tars and petroleum residues, which are preliminarily added to fuel after drying stage and to hot solid heat-carrier in contact chamber. Thereafter, resulted mixture is fed to pyrolysis stage in reactor. Apparatus for thermal processing of low-grade solid fuels such as blacks and brown coal is also described in Specification.

EFFECT: increased yield of low-sulfur hydrocarbon fuels including motor fuels due to additional pyrolysis of natural bitumen and petroleum residues.

6 cl, 2 dwg, 3 ex

Description

The invention relates to the thermal processing of high-ash and / or low-grade fuels, including oil shale, brown coal and can be used in oil shale processing, coal processing, petrochemical industries, as well as in the energy sector with the energy technology use of high-ash and other low-calorie (low-grade) fuels in power plants.

A known method for the thermal processing of brown coals, including crushing and drying coal, its pyrolysis with a solid heat carrier to obtain a vapor-gas mixture and a solid carbon residue. The gas-vapor mixture is purified and condensed by fractions of liquid products. The solid carbon residue is burned to produce a coolant returned to the pyrolysis stage (see A.I. Andryushchenko, A.I. Popov, “Fundamentals of the design of energy-technological installations of power plants. M: Higher School, 1986, p. 191-194).

The disadvantage of this method is the insufficient yield of valuable liquid and gaseous fractions, since only low-grade fuels are used as feedstock.

A known method of thermal processing of oil shale, including its grinding, mixing with heavy oil residues and cracking mixtures to produce valuable liquid products (RF patent No. 2178448, publ. 01.20.2002, class. C10G 9/00).

The disadvantage in this process is that oil shale is not used as the main raw material, but as an organomineral additive that stimulates an increase in the yield of liquid products during cracking of heavy oil residues.

A known method and installation for the thermal processing of high-ash fuels, for example oil shale, including pyrolysis using circulating solid heat carrier with the formation of gas-vapor products and coke-ash residue, burning the latter with the formation of gas suspensions, stepwise separation of the latter into a circulating solid coolant returned to the pyrolysis stage, and a gaseous drying agent; in this case, part of the flue gas after drying is recirculated by changing the flow rate of the zolodym mixture supplied for cooling, the organics contained in it are burned together with the spent drying agent before being discharged into the atmosphere (Patent No. RF 2118979, publ. 20.09.98, class С10В 53/06, 49/18).

The disadvantage of this method is the lack of recommendations and operating parameters that allow the processing of tars, bitumen and heavy residues of oil refineries together with pyrolyzable fuels (shale, coal), as well as the difficulty of binding sulfur in both pyrolysis gases and flue gases before dumping them into atmosphere requiring the use of expensive desulfurization equipment from N ₂ S and SO ₂ .

The closest technical solution related to the method is a method for thermal utilization of organic waste containing sulfur. As a solid fuel for pyrolysis, fine-grained oil shale is used, and solid particles of tire tires supplied in an amount of up to 10 wt.% From the initial shale and soils, sands contaminated up to 40% with hydrocarbon compositions supplied in an amount of up to 40% are used as organic waste. from the initial shale (patent No. RF 2117688, publ. 08.20.98, CL 10/53).

According to this method, thermal processing of oil shale is carried out according to the UTT scheme in a drum rotary reactor, where a stream of dispersed particles is supplied from the mixer, consisting of a mixture of fuel particles dried in an aero-fountain dryer and an ash coolant heated after an aero-fountain furnace, which is separated into a solid heat carrier flow through the mixer into the reactor for pyrolysis, the ash residue removed, and flue gases sent to the airborne dryer and discharged through separators, and electrophys tr into the atmosphere, and the method includes dry cleaning gas mixture into the reactor chamber pyleosaditelnoy provided with built-cyclones, the further condensation of the gas-vapor mixture to obtain a liquid resin fractions, high-calorie gas, pyrolysis of phenol-water.

The disadvantage of this method is that it provides for the pyrolysis of solid organic waste, soil, crushed tires in conjunction with the initial shale, which are fed for processing at the stage of fuel preparation before drying. The supply of liquid hydrocarbons before drying is excluded, because possible premature thermolysis, pyrolysis, sintering with the original fuel, etc. and the loss of part of the hydrocarbons from the release after drying with flue gases.

The closest technical solution related to the installation is an installation for the thermal processing of oil shale with a solid coolant (RF patent No. 2182588, publ. 05.20.2002, class C10B 53/06).

The known installation contains sequentially installed means for grinding shale, aero-dryer, a pyrolysis reactor and a process furnace. The pyrolysis reactor is connected to systems for purification and condensation of a gas-vapor mixture. The technological furnace is additionally connected via a cyclone of solid heat carrier to a pyrolysis reactor.

The mentioned installation for the thermal processing of oil shale with a solid heat carrier, which was used for the thermal processing of oil shale (pyrolysis), includes the step of drying fine-grained fuel in an aerofoil dryer, partial mixing in the preparation chamber of raw materials with a circulating hot solid heat carrier (ash) coming from an aerofont technological top , the stage of pyrolysis (semi-coking) in a drum rotating reactor with the formation of a vapor-gas mixture, afterburning of the coke-ash residue of pyrolysis directed and air-fountain in the reactor furnace, the flue gas cleaning step after air-fountain dryer step of dry cleaning the gas-vapor mixture in the chamber pyleosaditelnoy followed by fractional condensation of the vapor-gas mixture with release resin fractions, pyrolysis gas, pyrolysis of phenol-containing water.

The disadvantage of this installation is the lack of equipment for preparing for pyrolysis of liquid bitumen, tars and oil residues added to the shale, as well as reagents for binding sulfur to shale with a low content of calcium oxides. In addition, there is no constructive design of the primary contact chamber with the dried shale of liquid added hydrocarbons, which avoids coking of the chamber during uncontrolled contact with a high-temperature solid coolant.

The aim of the invention (method and installation) is to increase the yield of high-quality low-sulfur hydrocarbon, including motor fuels due to the additional pyrolysis of natural bitumen, oil refining wastes: tar, sour oil residues, together with the main pyrolyzable fuels, as well as ensuring the disposal of these wastes to protect the environment; liquidation of burial sites, reduction of costs associated with the construction of traditional treatment plants and facilities or waste incinerators.

In this case, desulfurization is carried out either due to the free calcium oxide contained in the mineral residue - shale ash, or when additional calcium oxide is supplied in a stoichiometric ratio to bind the sulfur of the initial fuel.

To eliminate the noted drawbacks and achieve technical results in the proposed method for the thermal processing of low-grade solid fuels, such as shale and brown coal, they are crushed, dried, pyrolyzed with a solid heat carrier together with the added hydrocarbon waste to produce a gas-vapor mixture and a solid carbon residue, the gas-vapor mixture is purified and condensed to obtain valuable liquid and gaseous products, a solid carbon residue is burned with the formation of a mixture of solid coolant and flue gases and separate the solid coolant from the flue gases; in this case, liquid hydrocarbons and oil wastes are used as hydrocarbon wastes, which are preliminarily added after the drying step to the dried solid heat carrier in the contact chamber in front of the reactor, and the resulting mixture is fed to the reactor for pyrolysis.

As hydrocarbon waste, natural bitumen is used, heated to 60-90 ° C, with the addition of solvent and fed to the mixing in an amount of up to 10-15 wt.% Of the processed solid fuel.

As hydrocarbon waste, tar is used, heated to 50-70 ° C, with the addition of solvent and fed to the mixing in an amount of up to 10-40 wt.% Of the processed solid fuel.

As heavy oil wastes, heavy oil residues with the addition of solvent are used, fed to the mixing in an amount of up to 50 wt.% Of the processed solid fuel.

To achieve this goal, the thermal processing plant for low-grade solid fuels contains a device for grinding crude fuel, a dryer, a pyrolysis reactor connected to purification and condensation systems of a gas-vapor mixture, a technological furnace connected to a pyrolysis reactor and equipped with a solid heat carrier cyclone, and a contact chamber connected to the input to the dryer and to the conclusion of the solid coolant from the cyclone, and the output to the pyrolysis reactor, and the installation additionally contains technological units for cooking hydrocarbon wastes connected to the input in the contact chamber before the reactor.

The contact chamber in front of the reactor for preliminary preparation of the pyrolyzable raw material with dried fuel has inputs of liquid processed hydrocarbons and the prepared liquid raw material is supplied to the moving layer of dried fuel at a height of 1.75 D along the generatrix of a cylindrical chamber with a diameter D.

Figure 1 presents a diagram of an installation that implements the method.

The installation contains a device for grinding 1 with a hopper 4 of crude fuel and a capacity of 2 finely dispersed calcium oxide (CaO) connected to a dryer 3. The contact chamber 9 is connected to the inlet of the reactor 13 and connected to the dryer 3 through a cyclone 7 and a sealing screw 8.

Technological units for the preparation of hydrocarbons 20 (bitumen), 22 (tar) and 24 (oil waste) are connected by exits to the preparatory contact chamber with the supplied dried fuel from 7-8 and heated solid heat carrier from cyclone 10 fuel. From the containers 21, 23, 25, a solvent is supplied for dilution, which is mixed in the apparatuses 26, 27 (in the case of bitumen and tar) and then the mixtures enter the storage tanks 28 and 29, from where they are sent to the chamber 9 by pumps Н1 and Н2.

The pyrolysis reactor 13 is connected to the outlet of the contact chamber 9 and to a cleaning system consisting of a dust collecting chamber 11 and built-in cyclones 12. The dust cleaning system through the outlet of the built-in cyclones is connected to the condensation compartment 30. The process furnace 14 is connected to the pyrolysis reactor 13 through a solid heat carrier cyclone 10, which is connected to the entrance to the contact chamber 9 in front of the reactor 13 through the cyclone 10 by the output of the solid heat carrier. The coke ash residue is left from the dust chamber 11 by means of the hot semi-coke screw 8 en with a technological furnace 14. From a technological furnace 14, a dust-gas mixture with a temperature of 750-800 ° C is sent through a flow divider (bypass) 15 to ash cyclones 16, from where the collected fine ash enters the ash heat exchanger 17, and the flue gases to the waste heat boiler 18 The bypass 15 is connected to the heat carrier cyclones 10, which capture the large heat-transfer ash, and the flue gases of 10 are mixed with the flue gases after the waste heat boiler 18 and enter the dryer 3.

A solid heat carrier from a heat carrier cyclone 10, as well as dried fuel from 8 and prepared liquid hydrocarbons from 28 and 29 with the help of pumps Н1 and Н2, and, if necessary, heavy pyrolysis residues from the condensation compartment 30 (XVII), are supplied to the upper part of the chamber 9.

The contact chamber in front of the reactor (figure 2) is a cylindrical vessel lined with refractory materials (D - diameter, height 3.5 D), in the middle part of which along the cylindrical generatrix 1.25 D, dried fuel is fed using a transport-sealing screw . The dried fuel is supplied with liquid hydrocarbon feedstock from feed preparation units 20-29. The supply of additional hydrocarbon raw materials should be carried out in an area where the temperature is 100-120 ° C, i.e. after the drying stage to a moving stream of dried fuel.

Installation works as follows. Streams are indicated by Roman numerals.

Fuel (shale) 1 (I) and finely divided calcium oxide 2 (II) through a crusher and an intermediate hopper 4 using a conveyor screw 8, equipped with weights 5, is fed into an air fountain dryer 3, where it is dried to a temperature of 110-130 ° C with flue gases with a temperature of 600-700 ° C and through a dry shale cyclone 7 is sent to the chamber 9.

Tar (VI) or bitumen (IV), or heavy oil residues (VII), are fed into the contact chamber 9 in a liquid state through the preparation processing units. After cyclone 7, flue gases (VIII) are discharged through the electrostatic precipitator 6 into the atmosphere. From the chamber 9, the mixture enters the reactor 13 (for example, into a rotary drum), where pyrolysis is carried out at 400-500 ° C. From the reactor 13 through the dust precipitation chamber 11, equipped with built-in cyclones 12, with the help of the screw 8, the semicoke is sent to the airborne technological furnace (AFT) 14, where the temperature of the gas-dust mixture reaches 700-850 ° C. AFT 14 is supplied with air (III) through the ignition chamber 19.

The gas-vapor mixture (ASG) after the dust collection chamber enters the condensation compartment 30. From the condensation compartment 30 after fractional condensation of the ASG rectification, separation, liquid products, the condensate is heavy fraction (XIII), middle fraction (XIV), light fraction (XV), gasoline fraction (XVI), semi-coke high-calorie gas (XVII), phenolic water, semi-coking (XVIII). It is also envisaged to connect part of its own heavy fraction (fus) to the prepared oil residue (V) supplied to the primary contact chamber.

The processing of bitumen, tar and heavy oil residues in the proposed method is achieved by the inclusion in the technological scheme of additional stages of preparation for the pyrolysis of bitumen, tar, oil residue.

The solvent (galosh gasoline or gasoline for industrial purposes) from the tank 21 (V ₃ ) and natural or petroleum bitumen 20 (IV) heated to 70-80 ° C is fed into the tank 26, where they are mixed and sent to the collection tank 29, from where the pump H2 is sent to the prepared contact chamber 9 of the pyrolysis compartment in front of the reactor.

Similarly for tars: solvent 23 (V ₂ ) with the addition of sulfuric acid neutralizing stoichiometric additives is mixed with tar 22 (VI) heated to 90 ° C and sent through a mixing tank 27 to a collecting tank 29, from where it is pumped into the chamber 9 after the drying stage by pump H2 fuel. Node 24, 25, 28 is designed to supply heavy petroleum sulfur-containing residues (NSO) for pyrolysis. The solvent 25 (V ₁ ) HCO with the addition of sulfur neutralizing chemical components, for example finely dispersed CaO, is sent to the collecting tank 28, from where it is fed to the chamber 9 by the pump Н1 after the fuel drying stage.

It is possible to add to the NSO part of the heavy fraction (XIII) obtained in the condensation compartment 30 in order to increase the yield of motor fuels.

Examples of specific implementation of the claimed method.

Example 1

As an object for the implementation of the method, the UTT-3000 installation was taken with a shale throughput of 3000 t / day (125 t / h).

To dry shale with a temperature of 120-130 ° C with characteristics, wt.%:

A ^c = 46.76; (CO ₂ ) ^c = 22.4; O ^c = 28.65; S ^c = 2,24; W ^p = 10-12%; Q = 2240 kcal / kg (938 MJ / kg) is added to the mixing chamber of 25 t / h of bitumen heated to 70 ° C (70% of bitumen and 30% of solvent are mixed) and 250-300 t / h of solid heat carrier (ash) are supplied at temperature 750 ° С.

The mixture enters the reactor, where at a temperature of 450-500 ° C, pyrolysis occurs with the release of the vapor-gas mixture (ASG) and the formation of semicoke. Shale ash contains free calcium oxide (CaO) in an amount of> 10%, which binds organic sulfur to sulphites (sulphates), which are converted to ash.

With the addition of bitumen, the amount of shale oil in total increased by 17.5%, from 125 l / t to 146.8 l / t (for working shale) or from 17.5 t / h to 20.5 t / h. The amount of sulfur in shale oil is less than 0.5%.

The amount of semi-coke gas increased by 50%.

Example 2

To the shale with the above characteristics, 30 t / h of liquid, heated to 60 ° С sulfur-containing (up to 7%) tar (a mixture of 85% tar, 15% solvent) are added to the mixing chamber (KS), and 250-300 t fall into the KS / h solid heat carrier at a temperature of 800 ° C. The mixture is fed to the reactor for pyrolysis, where it remains for 20-24 minutes, from where the ashed semi-coke is sent to the technological furnace (coke heater).

As a result, after condensation, 170 kg / t of shale oil and 80 kg / t of PCG, i.e. an increase in the output of shale oil from 17.5 t / h to 21.25 t / h, or by 21%, and an increase in the yield of PCG by 100%. The sulfur content in the liquid product does not exceed 0.4%.

Example 3

To the oil shale with a temperature of 130 ° C of the aforementioned composition, heavy petroleum sulfur-containing residues are added to the COP in the amount of 35 t / h (30 t / h residues and 5 t / h solvent), as well as 2 t / h of dispersed calcium oxide (<0, 5 mm). As a result of pyrolysis and subsequent condensation, 250 kg / t of dry shale of liquid products and a doubling of PCG are obtained.

Thus, the increase in liquid products will be from 125 to 250 kg / h or from 15.6 t / h to 31.2 t / h.

Equipment list

1. Pyrolysis fuel bin

2. The capacity of finely dispersed CaO

3. Aerial dryer

4. Intermediate hopper and crusher

5. Fuel transport with scales

6. Flue gas filter

7. Dry fuel cyclones

8. Screws for raw, dry fuel and semi-coke

9. A chamber for mixing dried fuel, coolant, hydrocarbon waste and additives

10. Heat carrier cyclones

11. Dust collecting chamber (PC)

12. Built-in PC cyclones

13. The drum or fluidized bed reactor (COP)

14. Technological furnace AFT or coke heater KS

15. Flow divider (bypass)

16. Ash cyclones

17. Ash heat exchanger

18. Heat recovery boiler

19. Ignition chamber

20. Bitumen tanks

21. 23, 25. Tanks for solvent

22. Tar Tanks

24. Tanks of heavy oil residues

26. The intermediate tank for mixing oil residues with solvent

27, 28. Mixing tanks for additional raw materials

29, 30. Tanks of prepared raw materials

31. Condensation unit

Н1, Н2 - pumps

Material flows

I. Pyrolyzable fuel

II. Calcium Oxide (Dispersed)

III. Air

IV. Bitumen

V. Solvent (V ₁ , V ₂ , V ₃ )

VI. Tar

VII. Oil heavy residues

Viii. Flue gas

IX. Ash after TT or coke after COP

X. Failure ash after firing furnace

Xi. Ash after ash heat exchanger

XII. Ash after KU

Xiii. Heavy condensate

Xiv. Middle fraction

Xv. Light fraction

Xvi. Gasoline fraction

Xvii. Semicoke gas

Xviii. Phenolic Pyrolysis Water

Claims (6)

1. The method of thermal processing of low-grade solid fuels, such as shale and brown coal, including grinding, drying, pyrolysis with a solid heat carrier together with hydrocarbon waste to produce a gas-vapor mixture and a solid carbon residue, purification and condensation of a gas-vapor mixture to produce valuable liquid and gaseous products, burning solid carbon residue to form a mixture of solid heat carrier with flue gases and separation from the solid heat carrier flue gases, characterized in that as hydrocarbon wastes use liquid hydrocarbons, bitumen, tars and oil wastes, which are preliminarily added to the fuel after the drying stage and to the hot solid heat carrier in the contact chamber, after which the resulting mixture is fed to the pyrolysis stage in the reactor. 2. The method according to claim 1, characterized in that the natural bitumen is used as hydrocarbon waste, heated to 60-90 ° C with the addition of a solvent and fed to the mixing in an amount of up to 10-15 wt.% Of the processed solid fuel. 3. The method according to claim 1, characterized in that tar is used as hydrocarbon waste heated to 50-70 ° C with the addition of solvent and fed to the mixing in an amount of up to 10-40 wt.% Of the processed solid fuel. 4. The method according to claim 1, characterized in that the heavy oil residues use heavy oil residues with the addition of solvent, supplied to the mixture in an amount of up to 50 wt.% Of the processed solid fuel. 5. Installation for the thermal processing of low-grade solid fuels, such as shale and brown coal, containing a device for grinding raw fuel, a dryer, a pyrolysis reactor connected to purification and condensation systems of a steam-gas mixture, a process furnace connected to a pyrolysis reactor and equipped with a solid heat carrier cyclone, and a contact chamber in front of the reactor, connected by the inlet to the dryer and to the output of the solid coolant from the cyclone, and the output to the pyrolysis reactor, characterized in that the installation additionally win process units and the preparation of hydrocarbon oil wastes, including storage tanks, and apparatuses for mixing the hydrocarbon feed with solvents and mixtures devices connected to the input in the contact chamber. 6. Installation according to claim 5, characterized in that the contact chamber for preliminary preparation of the pyrolyzable feedstock has inputs of liquid processed hydrocarbons and the feed of liquid feedstock is carried out to the flow of dried fuel at a height of 1.75 D along the generatrix of a cylindrical contact chamber with a diameter D.

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