DE102008032957A1 - Process for the production of synthetic diesel - Google Patents

Abstract

Process for the production of synthetic diesel from any carbonaceous raw materials, such. As household waste, rubber waste and biogenic material. Particularly high yields are achieved in a utilization of high-calorie fractions of waste and used tires. The starting materials are first burned at 86 to 90 kPa at 1200-1450 ° C with the addition of an oxygen-steam mixture and then gasified at 1100-1200 ° C. The resulting gas is purified and subjected to a three-stage Fischer-Tropsch synthesis. At each stage, the synthesis products Diete undergo further combustion / gasification. The required process water is usually obtained completely from the starting materials. Contaminated process water is reprocessed. Sulfur and CO2 from the process are separated, cleaned and stored. In the process, apart from ash from the mineral portion of the starting materials, no waste products are formed. The recovered diesel fuel is of high quality and can be easily used for vehicle operation.

Description

The The invention relates to a method for obtaining synthetic Diesel from any carbonaceous starting materials, such as. As household waste, rubber waste and biogenic material. Particularly high yields are at a utilization of highly calorific Fractions of garbage and scrap tires scored. apart of ash, which consists of the mineral part of the starting materials, fall in the process no waste materials.

by virtue of the oil shortage and the associated rising Fuel prices win processes for the production of fuel from carbonaceous waste or from biogenic substances more and more important. From the prior art are various Such methods are known.

So will in EP 0 863 197 A1 a process for the production of gasoline, diesel and carbon black from rubber and / or plastic waste described. The waste is first subjected to pyrolysis. The resulting products are cleaned, catalytically cracked and finally fractionated.

Of the produced fuel is not sorted. Also gets through the formation of the carbon black the economy of the process lowered, since the carbon black bound carbon is not is available for fuel production.

In the scriptures DE 10 2005 058 534 A1 . DE 10 2005 050 526 A1 and DE 10 2005 035 921 A1 In each case, parts of a process are disclosed in which carbonaceous starting materials are first pyrolyzed and then the pyrolysis gas is subjected to a Fischer-Tropsch synthesis.

Although the process provides high-quality diesel fuel, it is limited to biogenic raw materials. Another disadvantage is that it causes a high CO ₂ emission in the production of the fuel; Furthermore, comparatively high production costs are incurred.

In JP 2007 246 685 A introduces a process that first heats, melts and pyrolyzes wastes consisting of plastics, lubricants, car tires, edible oils or solvents. Thereafter, the pyrolysis gas is collected, condensed to pyrolysis and fractionated. The light fraction of the oil is separated, heated by means of a heat exchanger over hot combustion gases and returned to the pyrolysis chamber.

The process is limited to raw materials that already contain a high proportion of hydrocarbons. Another disadvantage is the high CO ₂ emissions.

task The invention is to find a method with which arbitrary carbonaceous raw materials inexpensive high quality Diesel fuel can be generated. In fuel production no waste materials should be produced except mineral ash; In particular, no toxic gases or greenhouse gases in the Environment.

These The object is achieved by the characterizing Features of claim 1 solved; advantageous embodiments The invention results from the claims 2 to 5.

At the inventive method for the production of Synthetic diesels are first carbonaceous sources crushed in the loading system with a shredder and then over funnel-shaped prechambers and closing devices introduced into the carburetor so that the carburetor opposite the ambient air always remains closed. This will be in the feed phase minimizes heat losses on the one hand, on the other hand it is avoided that polluting gases escape the carburetor.

The Temperature of the residues is before introduction into the carburetor kept at a temperature of 50 to 60 ° C, z. B. by an air cooling.

The Starting materials are converted into pyrolysis gas at a pressure of 86 to 90 kPa, by first in the gasifier at a temperature of 1200-1450 ° C burned, then at a temperature of 1100-1200 ° C. gasified and finally at a temperature of 850-900 ° C be removed from the carburetor.

There the combustion in a vacuum of 86 to 90 kPa and at temperatures less than 1500 ° C is formed comparatively little unwanted methane.

at Combustion is carried out using a starting material Oxygen generator pulsed a mixture of water vapor and oxygen added. The mixture is passed through a pressure of 0.13 MPa Nozzle in front of which there is a rotating grille shutter, introduced into the combustion zone of the carburetor. The mesh panel is in the carburetor and at the same time causes the shredding of sintered slag.

To reduce the slag formation is provided to add about 20% nitrogen to the mixture of steam and oxygen. The required proportion of nitrogen depends on the off starting material; If necessary, it can be determined more precisely by trial operation with about 1 t of the corresponding starting material.

The Pyrolysis gas is produced by means of thermally isolated cyclones of ash particles cleaned. The temperature of the gas is before the introduction into the cyclones always kept at a temperature of 850 to 900 ° C, to prevent the formation of dioxins and furans as much as possible. The thermal insulation of the cyclones must be so high quality that the temperature of the gas during cleaning at most 10 ° C is lowered.

Subsequently the gas is in a gas cooler with the exclusion of atmospheric oxygen within about 5 ms from 850 to 900 ° C to 130 ° C cooled. The heat given off becomes the Production of process steam at a temperature of 435 ° C and 3.4 MPa used to drive a gas turbine. The rapid cooling causes the formation of dioxins and furans - as desired - as far as possible prevented.

Venturi gas scrubbers are used to purify the gas of HCl and NH ₃ and partially of H ₂ S while simultaneously cooling it to 50-60 ° C. This is followed by another cleaning by centrifugal separators and electrical filters. For the Venturi gas scrubbers predominantly water recovered from the process is used.

Thereafter, the gas is compressed by means of pressure blowers and gas compressors and each purified in separate scrubbers of H ₂ S, CO ₂ and SO ₂ . Finally, resins, water and other liquid reagents are removed by means of a centrifugal separator.

The gas is heated to a temperature of 250-255 ° C, purified by a CO ₂ scrubber and then by a centrifugal separator and introduced into the synthesis column of the first stage, in which a temperature of 250-255 ° C, initiated. The synthesis column works by the Fischer-Tropsch process, using an iron-based catalyst suspended in heavy hydrocarbons with a boiling point greater than 350 ° C. If the ratio of CO to H ₂ in the gas is greater than 1.5, the gas before being introduced into the synthesis column is still fed to a converter in which CO is catalytically reacted with water to CO ₂ and H ₂ .

Of the reaction products formed in the Fischer-Tropsch synthesis of the first stage, diesel and gasoline are separated by means of a cooling tower. The heavy fractions such as heavy oil and masut are collected in the first stage synthesis column. Once a sufficient amount has accumulated, the heavy fractions are cleaned with a CO ₂ scrubber and a centrifugal separator and passed to the second stage synthesis column which operates on the same principle as the first stage column, but (geometrically) smaller than this is and is operated at temperatures of 280-300 ° C.

The reaction products formed in the second stage Fischer-Tropsch synthesis are separated and purified in an analogous manner. The heavy fraction is then passed to the third stage synthesis column, which is smaller than the column of the second stage and at same or slightly higher temperatures than the second Stage is operated.

From resulting from the third stage Fischer-Tropsch synthesis Reaction products is separated again the proportion of diesel and gasoline and with the diesel and petrol won in the other stages brought together a fuel storage tank. Included in it Residual water is separated by means of a centrifugal separator and after all, the diesel becomes petrol as well as tar separated by a rectification column.

The gasoline, the tar and the heavy fractions remaining after the three-stage Fischer-Tropsch process are returned to the combustion zone of the gasifier. The CO, H ₂ , CH ₄ , C _n H _n and N ₂ -containing residual gas is subjected to nitrogen purification and then also fed to the gasifier. Alternatively, after nitrogen purification, the gas may also be used or sold for gas powered electric generators.

For the implementation of the invention Process is predominantly water used in the Litigation is formed. It can be a big Part of the water from the residual moisture of the starting material more water is used in the chemical reactions, which occur during the process, formed. polluted Process water, especially when used in the venturi gas scrubbers is created, is completely recycled. To this Way, the procedure can be done regularly without feeding be carried out by external water. excess Water is bottled in the form of distilled water, stored for later occurring bottlenecks or can be sold. The feeder of external Water is only in exceptional cases, namely when too little moisture can be extracted from the starting materials required.

According to the essence of the invention it is provided that for the purification and treatment of the water used in the Venturi gas scrubbers this is purified in a first step by means of a hydrocyclone of hydrocarbons. The hydrocarbons accumulate with higher density than water in the lower and those with lower density in the upper zone of the hydrocyclone. The separated hydrocarbons are supplied to the combustion zone of the gasifier; the introduction takes place within the time windows in which no mixture of oxygen, water vapor and nitrogen is introduced into the combustion zone.

Thereafter, H ₂ S is removed from the water using an H ₂ S scrubber. It is then passed to a surge tank for the second purification of hydrocarbons. The higher density hydrocarbons accumulate in the lower and lower density regions in the upper region of the surge tank; The hydrocarbons are introduced into the gasifier in an analogous manner as the hydrocarbons separated off during the first purification.

through a membrane filter will still remaining hydrocarbons as well as other impurities removed from the water and the carburetor fed. Finally, the water is from the last traces of hydrocarbon, of dissolved gases and ammonia using a standard water purification unit cleaned and collected in a storage tank. The saved Water can be used as process water for the gas scrubber and for the formation of the process steam for the carburetor or be used for the operation of steam turbines. at Excess water can also be used as condensed cooling water be used for external equipment.

For purifying the pyrolysis gas of H ₂ S it is intended to use a gas scrubber with a 30% (CH ₃ ) ₂ NCH ₂ CH ₂ OH solution. The H ₂ S from the pyrolysis gas is converted into pure sulfur by means of a Claus apparatus and packaged.

In order to purify the gas of CO ₂ , a foam absorber is preferably used as the CO ₂ gas scrubber, in which the CO ₂ is absorbed by an aqueous K ₂ SO ₃ solution to form K ₂ CO ₃ . The bound in the aqueous solution of CO ₂ is then expelled again in a separation tower, compressed by means of a compressor and bottled.

To purify the gas of SO ₂ , an SO ₂ gas scrubber is used, in which a 10% lime milk solution is.

The process, apart from ash from the mineral portion of the starting materials, no waste products. This is achieved by the consistent recycling of the hydrocarbon-containing reaction products that are formed in addition to diesel, by the largely closed water system and by the separation, purification and storage of sulfur and CO ₂ . The recovered diesel fuel can be easily used for vehicle operation; in particular, it exceeds the requirements of D590.

The Invention will be described below with reference to an embodiment explained in more detail; show:

Fig. Part A : Flow diagram showing the pyrolysis, pre-cleaning of the pyrolysis gas and purification of the process water;

Fig. Part B : Flow chart showing the purification of the pyrolysis gas;

Fig. Part C Figure: Part of a flow chart showing the three-stage Fischer-Tropsch synthesis.

As shown in Fig. Part A As can be seen, the carbonaceous starting materials through the loading system 1 the four carburetors 2 fed. In the loading system, the starting materials are crushed on the one hand and on the other hand, it ensures via a lock system that no air exchange between the carburetor and the environment can take place. In addition, it prevents excessive heating of the starting materials before introduction into the carburetor.

In the gasifier, the starting materials pass through the three temperature zones of combustion, gasification and gas separation. In the combustion zone of the carburetor 2 a mixture of oxygen and water vapor and about 20% nitrogen is introduced. The oxygen required for this purpose is provided by the oxygen generator 3 provided.

The pyrolysis gas produced in the gasifier from the raw materials is maintained at a temperature of 850 to 950 ° C and in one of the four gas cooler 4 cooled to 130 ° C within about 5 ms. In this way the formation of dioxins and furans is minimized. The heat released during cooling is used to generate process steam, with which the steam turbine 39 is operated.

The gas is first cleaned to one of the four venturi gas scrubbers 5 , then one of the centrifugal separators 6 and finally one of the electrical filters 7 fed.

Subsequently, the gas first passes through the pressure blower to compress it 8th and since after the gas compressor 9 , The compressed gas is successively each of H ₂ S, CO ₂ and SO ₂ with the H ₂ S, CO ₂ and SO ₂ gas scrubber 10 ; 11 ; 12 cleaned (Fig. Part B ). In the centrifugal separator 13 Finally, in the first stage of the synthesis, a separation of resins and water takes place.

From the extracted from the gas H ₂ S is with the Claus plant 35 pure sulfur obtained with the packaging machine 36 is packaged. CO ₂ , the CO ₂ gas scrubber 11 was absorbed by an absorber solution, with the separation tower 37 again expelled from the solution. The released CO ₂ is using the CO2 gas compressor 38 bottled in gas bottles.

If the ratio of CO to H ₂ in the synthesis gas is greater than 1.5, this becomes the converter first 15 fed, in which CO is catalytically converted together with water to CO ₂ and H ₂ . If the ratio is less than 1.5, the gas is via the CO ₂ gas scrubber 21 the Fischer-Tropsch synthesis column 14 fed to the first stage (Fig. Part C ). With the cooling tower 16 is separated from the reaction products diesel and gasoline, the remaining reaction products, which consist essentially of the heavy fraction and gaseous components, via the CO ₂ gas scrubber 22 and the centrifugal separator 23 the synthesis column 17 fed to the second stage. The reaction products formed there are analogous to the first stage in the cooling tower 18 separated and the residues via the CO ₂ gas scrubber 24 and the centrifugal separator 25 the synthesis column 19 supplied to the third stage. With the cooling tower 20 Diesel and gasoline are again separated from the reaction products, and together with the diesel and gasoline, which was formed in the first two stages, into the fuel storage tank 27 directed. Contained in the mixture residual water is by means of the centrifugal separator 28 separates and finally the diesel from the gasoline and tar residues with the rectification column 29 separated.

The gasoline, tar, and heavy fractions unreacted by the three-stage Fischer-Tropsch process are sent to the combustion zone of the gasifier 2 brought in. CO, H _2, CH _4, C _n H _n and N ₂ containing residual gas is CO ₂ -Gaswäscher 26 and the nitrogen cleaner 40 passed and then also fed to the carburetor.

For reprocessing in the venturi gas scrubbers 5 It passes through the hydrocyclone in succession with process water contaminated with hydrocarbons and other residues 30 , the equalization tank 31 , the membrane filter 32 and the water purification unit 33 , The purified water will eventually be in the collection tank 34 directed.

1

loading system

2

carburettor

3

oxygen generator

4

gas cooler

5

Venturi scrubber

6

cyclone (Gas cleaning)

7

electrical filter

8th

pressure blower

9

gas compressor

10

H ₂ S gas scrubber

11

CO ₂ gas scrubber

12

SO ₂ gas scrubber

13

cyclone (first stage)

14

synthesis column (first stage)

15

converter

16

cooling tower (first stage)

17

synthesis column (second step)

18

cooling tower (second step)

19

synthesis column (third step)

20

cooling tower (third step)

21

CO ₂ scrubber (first stage)

22

CO ₂ scrubber (second stage)

23

cyclone (second step)

24

CO ₂ scrubber (third stage)

25

cyclone (third step)

26

CO ₂ gas scrubber (after-cleaning)

27

Fuel collection tank

28

cyclone (before rectification)

29

rectification column

30

hydrocyclone

31

balance tank

32

membrane filter

33

Water purification unit

34

collection tank

35

Claus plant

36

packaging machine

37

separation tower

38

CO ₂ gas compressor

39

steam turbine

40

nitrogen cleaner

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 0863197 A1 [0003]
• - DE 102005058534 A1 [0005]
• DE 102005050526 A1 [0005]
• - DE 102005035921 A1 [0005]
• - JP 2007246685 A [0007]

Claims (5)

Process for the production of synthetic diesel from carbonaceous raw materials, preferably from the high-calorie fraction of waste, comprising the steps of - introducing comminuted carbonaceous raw materials into at least one gasifier ( 2 ) by means of a loading system ( 1 ) consisting of a shredder, funnel-shaped prechambers and closing devices such that the carburetor ( 2 ) relative to the ambient air is always completed, the temperature of the starting materials in the antechambers, is maintained at 50 to 60 ° Celsius by air cooling, - generating gas from the starting materials at a pressure of 86 to 90 kPa, the starting materials in the carburetor first for combustion at a temperature of 1200-1450 ° C, then subjected to gasification at a temperature of 1100-1200 ° C and finally during gas extraction to a temperature of 850-900 ° C, and during combustion of the raw materials by means of an oxygen generator ( 3 ) is added in a pulsed manner to a mixture of steam, oxygen and 0 to 30% of nitrogen by pumping it into the combustion zone of the carburetor at a pressure of 0.13 MPa via a nozzle in front of which there is a rotating grille shutter. 2 ), - purifying the gas of ash particles by means of thermally insulated cyclones, the temperature of the gas being maintained at a temperature of 850 to 900 ° C before introduction into the cyclones, and the temperature of the gas in the cyclones not exceeding 10 ° C Cooling of the gas from 850 to 900 ° C to 130 ° C with exclusion of atmospheric oxygen within 5 ms in gas coolers ( 4 ), wherein the heat released is used to produce process steam having a temperature of 435 ° C and 3.4 MPa, which is used to drive a gas turbine ( 29 ), - purifying the gas of HCl and NH ₃ and partially of H ₂ S while cooling the gas to 50-60 ° C by means of Venturi gas scrubbers ( 5 ), then further cleaning by means of centrifugal separators ( 6 ) and electrical filters ( 7 ), whereas for Venturi gas scrubbers ( 5 ) used in the process, from which, after its use in the Venturi gas scrubbers ( 5 ) Impurities are separated in the form of hydrocarbons and which is subsequently prepared for reuse, - compression of the gas by means of pressure blowers ( 8th ) and gas compressors ( 9 ), - purifying the gas of H ₂ S, CO ₂ and SO ₂ in separate gas scrubbers ( 10 . 11 . 12 ), - removal of liquid reagents, resins and water by means of a centrifugal separator ( 13 ), - heating the gas to a temperature of 250-255 ° C, cleaning of CO ₂ by means of a CO ₂ scrubber ( 21 ) as well as introduction into a synthesis column ( 14 ) of a first stage operating according to the Fischer-Tropsch process at 250-255 ° C using an iron-based catalyst suspended in heavy hydrocarbons having a boiling point greater than 350 ° C, where, when prior to carrying out the fishery Tropsch synthesis the ratio of CO to H ₂ in the synthesis gas is greater than 1.5, a portion of the gas prior to synthesis in a converter ( 15 ) is conducted, in which CO is catalytically converted together with water to CO ₂ and H ₂ , - separating the in the synthesis column ( 14 ) formed diesel and gasoline from the remaining synthesis products by means of a cooling tower ( 16 ), the heavy fractions such as heavy oil and masut in the synthesis column ( 14 ), and, if a larger amount has accumulated, after cleaning by means of a CO ₂ scrubber ( 22 ) as well as a centrifugal separator ( 23 ) in the synthesis column ( 17 ) of a second stage operating on the same principle as the column ( 14 ) works the first stage, but is geometrically smaller than this and is operated at higher temperatures of 280-300 ° C, - separating the in the synthesis column ( 17 ) formed diesel and gasoline from the remaining synthesis products by means of a cooling tower ( 18 ), the heavy fractions in the synthesis column ( 17 ), and, as soon as a larger amount has accumulated, after cleaning by means of a CO ₂ scrubber ( 24 ) as well as a centrifugal separator ( 25 ) in the synthesis column ( 19 ) of a third stage operating on the same principle as the other columns, but smaller than the column ( 17 ) is operated at the same or slightly higher temperatures than the second stage, - separation of the in the synthesis column ( 19 ) formed diesel and gasoline from the remaining synthesis products by means of a cooling tower ( 20 ), Bringing together the diesel and gasoline obtained in all three stages in the fuel collection tank ( 27 ), Separation of residual water in a centrifugal separator ( 28 ) and separation of the diesel from the gasoline and tar residues by means of a rectification column ( 29 ), - returning the gasoline, the tar and the heavy fractions remaining after the three-stage Fischer-Tropsch process, and the residual gas containing CO, H ₂ , CH ₄ , C _n H _n and N ₂ , after having been subjected to nitrogen purification, in the combustion zone of the carburettor ( 2 ). A method according to claim 1, characterized in that the cleaning and treatment of the in the Venturi gas scrubbers ( 5 ) used water the steps - first separation of hydrocarbons from Water by means of a hydrocyclone ( 30 ), wherein the hydrocarbons collect at higher density than water in the lower and those with lower density in the upper zone of the hydrocyclone, and recycling the separated hydrocarbons in the combustion zone of the carburetor ( 2 ), within time windows in which no steam-oxygen mixture is introduced into the combustion zone, - purification of the water of H ₂ S by means of an H ₂ S scrubber, - second separation of hydrocarbons from the water by introduction into a surge tank ( 31 ), whereby the hydrocarbons with higher density in the lower and those with lower density in the upper region of the surge tank ( 31 ) and recycling the separated hydrocarbons into the combustion zone of the gasifier ( 2 ), within time windows in which no water vapor-oxygen mixture is introduced into the combustion zone, - Separating the remaining hydrocarbons and other impurities by means of a membrane filter ( 32 ), - purification of water from traces of hydrocarbons, dissolved gases and bound ammonia by means of a water purification unit ( 33 ) and collecting the water in a collection tank ( 34 ) for further use as process water for the gas scrubber ( 5 ), for the formation of process steam for the operation of steam turbines ( 39 ) or in the case of excess water as condensed cooling water for external installations. A method according to claim 1 and 2, characterized in that the cleaning of the gas of H ₂ S in the H ₂ S gas scrubber ( 10 ) using a 30% (CH ₃ ) ₂ NCH ₂ CH ₂ OH solution, wherein the extracted H ₂ S by means of a Claus plant ( 35 ) converted into sulfur, and with a packaging machine ( 36 ) is packaged. A method according to claim 1 to 3, characterized in that for the purification of the gas of CO ₂ as CO ₂ gas scrubber ( 11 ) a foam absorber is used in which the CO ₂ is absorbed by an aqueous K ₂ SO ₃ solution to form K ₂ CO ₃ , and then the bound CO ₂ from the K ₂ SO ₃ solution by means of a separation tower ( 37 ) is expelled again, wherein the CO ₂ thereby obtained by means of a gas compressor ( 38 ) is bottled. A method according to claim 1 to 4, characterized in that for the purification of the gas of SO ₂ in the SO ₂ gas scrubber ( 12 ) using a 10% lime milk solution.