|Title of Invention||
DIESEL OIL FROM WASTE BY CATALYTIC DEPOLYMERISATION HEATED IN A PUMP MIXING SYSTEM
|Abstract||Production of diesel oil from hydrocarbon-containing residues in an oil circuit with solids separation and product distillation for the diesel product with energy input by means of pumps and counterrotating agitators and by the use of fully crystallized catalysts of potassium, sodium, calcium, and magnesium-aluminum silicates, where all surfaces are cleaned continuously by the agitator mechanisms.|
DIESEL OIL FROM RESIDUES BY CATALYTIC DEPOLYMERIZATION WITH ENERGY INPUT FROM A PUMP-AGITATOR SYSTEM
The invention comprises a process and a device for the catalytic cracking of hydrocarbon molecules at temperatures of 300-400°C using alkali-doped aluminum silicates as catalyst, where the energy input is provided primarily by a combination of pumps and agitators, which are connected to a separation tank for the separation of mineral contaminants.
Catalytic depolymerization using a special catalyst consisting of sodium-doped aluminum silicate is known from Patent No. 100 49 377. With the use of this catalyst, the hydrocarbon-containing residue is cracked into diesel oil and gasoline. The heat required to produce the energy for cracking, the energy required to evaporate the cracked hydrocarbons in the form of diesel oil and gasoline, and the energy for the initial heating phase and also the heat required to make up for losses are supplied in this case by heating through the wall.
The disadvantage of this process is that, because of the wall, the heating temperature must be higher than the reaction temperature. As a result, a certain amount of reaction coke is always formed. When the temperature of the wall increases relative to the temperature of the reaction mixture, that is, when a certain production output is to be obtained, the amount of coke will also increase.
This reaction coke now reacts with the sodium-doped aluminum silicate to form a nonreactive residue, which contaminates the system and brings the reaction to a standstill. This reaction mixture of catalyst and reaction coke interacts with the wall of the device, forming a hard residue, and a great deal of effort is required to clean it off during the scheduled maintenance intervals. The invention thus describes only a procedure, not an economical process.
An economical process is therefore impossible to obtain by heating the wall intensively, that is, by attempting to supply heat actively by conducting it through the wall.
The lower thermal conductivity of the reaction oil in the circuit results in a greater temperature difference between the heating located externally on the wall and the reaction in the oil, which the cracking energy (depolymerization), the evaporation energy, and the heating energy require.
If there is only waste oil and tars in the oil circuit, approximately 0.'4 kWh of energy is required per kg of evaporated diesel for cracking, for evaporation, and for raising the temperature from the inlet temperature of 250°C to the reaction temperature of 390°C. When plastics are added to the feedstock, the energy requirement is almost twice as high, because these materials are loaded cold and because extra energy is required to melt them.
A surprising heat input process and a suitable catalyst have now been discovered, which completely avoid these disadvantages. The system does not transport heat through the wall but rather releases the heat directly in the reaction system.
The energy is supplied by a system consisting of a pump and a counterrotating agitator or mechanical stirrer system, followed by separation of the diesel oil vapor in a highspeed hydrocyclone. The agitator systems also serve to clean all of the surfaces in the circuit.
The catalyst is also a new development. The doping of a fully crystallized Y molecule with sodium was found to be optimal only for plastics, bitumen, and waste oils. For biological feedstock such as grease and biological oils, doping with calcium was found, to be optimal. For the reaction with wood, doping with magnesium is necessary to produce high-quality diesel oil. For the highly halogenated compounds such as transformer oil and PVC, it is necessary to dope with potassium.
The product of the system is diesel oil, because the product discharge from the circuit at 300-400°C leaves no other lighter products behind in the system. 10% of this product is used to generate the process energies in the form of electric current in a power-generating unit. The advantage of this energy conversion is the simultaneous solution of the problem of what to do with the small amounts of gas which form in the system: this gas is
added to the feed air, and the thermal energy of the exhaust gases of the power generator is used to predry and to preheat the feedstock.
Figure 1 shows a diagram of the process according to the invention. The pump is designated 1, the suction side 2 of which has the feed hopper 3 and a connection to the circulating oil line 4. On the output side is the pressure line 5, which leads at a tangent into the agitation tank 6. An agitator 7, driven by the electric motor 8 and rotating in the direction opposite the tangential arrival of the feedstock is provided in the tank. The agitator 7 is also provided with upward-pointing cleaning arms, which pass over the entire surface of the agitation tank.
The agitation tank 6 is connected by a connecting pipeline 9 to a hydrocyclone 10. An automatic control valve 11, which regulates the pressure in the downstream apparatus, is installed in this connecting pipeline. In a special embodiment, an additional pump is provided in this line; this pump is controlled as a function of pressure by way of a frequency converter along with the pump 1. The hydrocyclone 10 has in its interior a venturi nozzle 12 resting against the inside wall, which also lowers the remaining excess pressure and amplifies the separation effect.
Above the hydrocyclone there is a safety tank 13, which has an automatic level control device 14 with an oil level meter 15. An agitator mechanism is mounted on the safety tank 13; this agitator is driven by an electric motor and has cleaning arms for the lower part of the safety tank, for the cyclone, and for the tank underneath the cyclone.
From one side of the safety tank 13, the product vapor line 16, which carries the diesel vapor produced, leads to the distillation unit 17 with the condenser 26. The condenser 26 is a water-cooled condenser of the bundled-tube type, the water being recycled through the coolant circuit.
Any water which may have formed is separated in the forward part of the condenser 26. This is discharged separately with the help of a conductivity sensor and an automatically controlled drain valve, with the result that no water is present in the product. The diesel
product is conducted away at the top of the column through the upper discharge port. The quality of the diesel oil is automatically controlled via the reflux line by appropriate adjustment of the reflux rate.
The reflux line has a connection to the diesel supply tank of the power generator 27, which supplies the system with current. This generator consumes approximately 10% of the produced diesel oil to generate the power required by the plant itself, and the exhaust gas of the motor also provides the heat used to predry and to preheat the oils.
All the tanks are equipped with external electrical heating units to facilitate the heat-up phase. Underneath the hydrocyclone 10 there is the separation tank 18 with its slanted plates 19, which ensure the separation of the constituents of the feedstock which cannot be converted to diesel oil.
This separation tank 18 is connected to the suction pipe 2. At the bottom of the separation tank 18 there is a temperature sensor 25, which puts the discharge screw 20 into operation when the temperature falls at the temperature sensor 25 below a certain limit value as a result of the insulating effect of the resides.
The discharge screw 20 has a filter section 21 within the tank, which allows the liquid components to flow back through the filter screen 22 into the separation tank 18, and an electrically heated low-temperature carbonization section 23 outside the separation tank 18, which allows the remaining oil fractions to evaporate from the press cake. For this purpose, provisions are made to increase the temperature to as high as 600°C. The oil vapors escaping from the low-temperature carbonization conveyor section 23 pass through the vapor line 24 and thus arrive in the safety tank 13.
The invention is explained in greater detail below on the basis of an exemplary embodiment. A rotary pump with a drive power of 200 kW conveys feed oil at a rate of 5,000 L/h from a suction line 2 and 600 kg of resides in the form of waste oil and bitumen at a total rate of 5,600 L/h from the material feeder 3 into the pressure line 5, which leads tangentially into the agitation tank 6 with a diameter of 1,400 mm. An agitator 7, which rotates in the
opposite direction, is installed in the tank and is driven by the 40-kW electric motor 8. The agitator 7 also has upward-extending cleaning arms, which pass over the entire surface of the agitation tank, that is, both the lower part of the agitation tank with a diameter of 1,400 mm and also the upper part with a diameter of 500 mm.
The agitation tank 6 is connected by a connecting pipeline 9 with a diameter of 200 mm to a hydrocyclone 10. An automatic control valve 11 is installed in the connecting line to regulate the pressure in the downline apparatus. The hydrocyclone 10 has a diameter of 1,000 mm, and in its interior it has a venturi nozzle 12 positioned on the inside wall with a narrowest cross section of 100 x 200 mm, which also lowers the remaining excess pressure and increases the separation effect.
A safety tank 13 with a diameter of 2,000 mm and an automatic level control device 14 with an oil level meter 15 are installed above the hydrocyclone. An agitator is mounted to the safety tank 13; this agitator is driven by a 10-kW electric motor and has cleaning arms for the lower part of the safety tank, the cyclone, and the tank situated underneath the cyclone.
To the side of the safety tank 13, the product vapor line 16 for the diesel vapor produced leads to the distillation unit 17 with a column diameter of 500 mm. All tanks are equipped with external electric heating with a total output of 50 kW to facilitate the heat-up phase.
Underneath the hydrocyclone 10 is the separation tank 18 with a diameter of 2,000 mm. This tank has slanted disks 19, which ensure the separation of the constituents of the feedstock which cannot be converted to diesel oil. This separation tank 18 is connected to the suction pipe 2, which has a diameter of 200 mm. A temperature sensor 19, which puts the discharge screw 20 into operation when the temperature has fallen below a certain limit value as a result of the insulating effect of the residues, is installed at the bottom of the separation tank 18.
The discharge screw 20, which has a diameter of 80 mm and a delivery rate of 10-20 kg/h, has a filter section 21 within the tank, which allows the liquid components to flow back
through the filter screen 22 into the separation tank 18, and an electrically heated low-temperature carbonization section 23 outside the separation tank 18 with a heating power of 45 kW, which allows the remaining oil fractions to evaporate from the press cake. For this purpose, provisions are made to increase the temperature to 600°C. The oil vapors escaping from the low-temperature carbonization screw 23 pass through the vapor line 24 and arrive in the safety tank 13.
Reference Numbers of Figure 1
1 pump for energy input
2 suction side of the pump
3 material feeder (input)
4 supply of circulating oil (input 2)
5 pressure line, tangential
6 agitation tank
7 agitator (rotates in opposition to the tangential pressure line)
8 electric motor for the agitator
9 connecting pipeline to the hydrocyclone
11 adjusting valve for automatic pressure regulation
12 venturi nozzle, resting against the inside surface of the hydrocyclone
13 safety tank
14 automatic level control device
15 level indicator and automatic control
16 product vapor line
17 distillation unit
18 separation tank
19 slanted disks in the separation tank
20 discharge screw
21 filter section of the discharge screw
22 filter screen of the filter section of the discharge screw
24 low-temperature carbonization section of the discharge screw (to 600°C)
25 temperature sensor underneath the solids separation unit
27 power generator
1. Process for producing diesei oil from hydrocarbon-containing residues in an oil circuit with solids separation and product distillation for the diesel product, characterized in that the primary energy input and thus the primary heating is accomplished by one or more pumps.
2. Process according to Claim 1, characterized in that the flow energy of the pump is braked (counteracted) by an agitator, which rotates in the opposite direction, and is converted to heat.
3. Process according to Claims 1 and 2, characterized in that, depending on the application, the catalysts used for the catalytic conversion are in the form of fully crystallized Y molecules doped with sodium for mineral type hydrocarbons such as bitumen, oils, and plastics, and in that catalysts doped with calcium are used for biological feedstocks such as greases and biological oils, and in that doping with magnesium is used for the reaction with wood, where catalysts doped with potassium are used for the highly halogenated compounds such as transformer oil and PVC.
4. Process according to Claim 1, characterized in that the remaining flow energy of the pump is regulated by an automatically controlled flap valve in the upper circulation pipe and by the venturi nozzle in the cyclone.
5. Process according to Claim 1, characterized in that the plant has an automatic temperature control device and an automatic level control device, which are networked with each other; that is, the feed and energy input systems are controlled in such a way that the level remains constant.
6. Device for implementing the process, characterized in that the plant comprises the following components: a high-power pump, a counterrotating agitator, an automatic throttle valve, a separating cyclone in the circuit, and a separation tank with heated discharge screw at one outlet of the plant and distillation unit at the other outlet.
7. A process fro producing diesel oil from hydrocarbon-containing residues substantially as herein described with reference to the accompanying drawings.
|Indian Patent Application Number||747/CHE/2004|
|PG Journal Number||51/2009|
|Date of Filing||02-Aug-2004|
|Name of Patentee||ALPHAKAT GMBH|
|Applicant Address||SCHULSTRASSE 8, D-96155 BUTTENHEIM, GERMANY|
|PCT International Classification Number||C10G 1/02|
|PCT International Application Number||N/A|
|PCT International Filing date|