EP2693060A1 - Reaction pump for splitting hydrocarbon chains - Google Patents

Abstract

The device has an impeller (3) rotating in a reactor housing (2), and a shaft located at two sides of the impeller. The housing is arranged with shaft bearings (1), which are positioned on two sides and spaced apart from each other and arranged outside of a region for process liquid. An oil chamber (7) is located in an interior region of the housing according to two shaft feedthroughs. The oil chamber is formed by partition walls and a throttle pipe (8) surrounding the shaft. A process fluid input (5) and a process liquid output (6) are attached to the chamber.

Description

The invention relates to a device for the splitting of hydrocarbon chains used in a thermo-catalytic conversion process in which from biomass and other hydrocarbonaceous materials gaseous or liquid fuels can be obtained.

Background of the invention

By entering into a hot oil cycle, carbonaceous materials can be heated, freed of their water content and then, with the addition of a catalyst, decomposed in a housing by the action of a rotating impeller and split the hydrocarbon chains contained by mechanical action and the effect of the input catalyst.

The resulting by the cleavage short chain hydrocarbon compounds whose evaporation temperatures are lower than the temperatures of the process liquid separated in the course of the process fluid circuit by evaporation from the process liquid and are condensed by distillation to liquid fuel, mainly middle distillate.

Various processes are known in which, as in the process described here, the splitting of hydrocarbon chains under low pressure and temperatures of only 250 ° C.-400 ° C. is achieved by the use of catalysts.

Most of these processes, which differ from pyrolysis due to the markedly low temperature and pressure levels, are based on the fundamental principle of chemical pyrolysis by Prof. dr. Ernst Bayer 1980 in the University of Tübingen developed so-called low-pressure thermal conversion process (Euro patent disclosure 1982 under the number EP0052334 ) are approaching the project to transform the same into an economically viable facility but with very different approaches to the technical implementation.

Not only in terms of lower energy consumption, but also in terms of environmental compatibility are low-temperature pyrolysis methods preferable because no dioxins can get into the environment, as they do not arise at low temperatures.

For many years already, by utilizing this chemical reaction, hydrocarbon chains can be broken down and fuel extracted over a limited period of time, whether by an externally electric or flame heated reactor, or by a reactor in which heat is internally generated by mechanical movement of vanes or impellers Energy is registered.

None of the previously known methods but so far, taking into account the lifetime of all components and the resulting cost-benefit calculation suitable for continuous operation on an industrial scale.

That from Dr. Christian Koch filed proceedings - DE 10 2009 012 486 A1 2010.10.14 in which the introduced into the system heat is obtained by mechanical action within a rotating according to the basic principle of the liquid ring vacuum pump impeller, compared to previous versions with heating from the outside is a significant improvement, because the high-maintenance verkoksen on the inside of the outside heated container walls is thereby avoided, and the heating process is coupled simultaneously with an advantageous for the process intensive mixing process.

Liquid ring used for use in such processes Vacuum pumps and other devices constructed according to the basic principle of the liquid ring vacuum pump are suitable for showing in a test setup over a certain period of time that it is possible to carry out this conversion process in this way.

In tests, however, it has been shown that all the previous technical versions do not withstand continuous operation on an industrial scale.

Due to very short service life of the shaft bearings of the rotating in the reactor housings impellers an industrial application is not yet possible, as well as the wave sealing method are not sufficient, since at the shaft escaping oil at temperatures above 300 ° C partially no longer drips but evaporated.

A big difference is that process-related moves in this new application of a well-known pumping principle instead of gas or air at room temperature, liquids, solids and abrasive catalysts at temperatures up to 350 ° C.

The assumption that the high oil content of the process fluid ensures good or at least adequate lubrication for the shaft bearings arranged in the process fluid area has not been confirmed in tests.

The life of the shaft bearings reached in tests of corresponding devices with shaft bearings in the area traversed by the process liquid partially only 30 hours at best 250 hours, whereas where a prototype of the device according to the invention described with external, double, and according to the manufacturer properly lubricated shaft bearings, already Since December 2011 in a pilot plant in permanent continuous use under operating conditions without the hitherto even the slightest problem with the camps would have shown.

Due to high effort in the commissioning of a system and high costs after switching off a system, as well as the central installation position of the device described here can be made economically viable use only with a device that meets requirements for industrial continuous use.

In the case of the housing design and construction, with regard to devices that have been produced, it has hitherto been assumed that the high proportion of oil in the process fluid lubricates the internal bearings or it is attempted to isolate the shaft bearings from the process fluid region only with hydraulic seals. Since hydraulic seals are non-contact seals, not physical closures, only the amount of process liquid flowing into the bearings can be restricted, but a fundamental entry can not be prevented.

When arranging the shaft bearings within the area through which the process fluid flows, although the process fluid mainly consists of oil, the entrained solid particles settling in the bearings lead to lubrication faults, but above all lead to the aluminum silicates carried along in the process fluid and necessary for the process. as well as lime used as an acidity regulator by high abrasiveness even with smaller quantities after a short time to severe damage to the shaft bearings.

With the amounts of raw materials that are introduced into the process, inevitably constantly, for the process otherwise harmless amounts of dirt, sand and some smaller stones etc. are introduced into the process liquid, which is another important reason for a housing design with process liquid not represents achievable shaft bearings.

For a device in which highly loaded shaft bearings have a central function, can meet industrial requirements, a pollution-proof installation position and lubrication of these bearings with lubricants recommended by the manufacturer is necessary.

the solution of the problem

By means of the device according to the invention described extension of the shaft and arranged outside the process fluid area, each positioned at a certain distance from each other, two shaft bearings per side, the shaft bearings are now in operation, neither high temperatures, nor abrasive catalysts or acidity regulators, nor contamination exposed to the raw material input, run in a clean environment with proper lubrication and now, together with the high increase in shaft stability by the spaced apart with a double shaft bearing, despite the extension of the non-supported bearing area, a long service life.

Background of the improvement of the shaft seal system

Taking into account the state of the art today, stuffing box packing seals, which must always be adjusted to a certain degree of leakage for proper operation, should not be the first choice for applications in the range above 300 ° C.

Although the packing materials are resistant to temperatures well above 500 ° C, but also heavier oils begin to evaporate from 280 ° C, with the effect that at lower temperatures otherwise tolerable leakage, does not drip outside and can be easily collected, but the Partly evaporated outlet and thereby forms toxic fumes that escape into the environment and even for people who work on such a system are intolerable.

For mechanical seals, the service temperature is not limited by the thermal loading capacity of the sealing slip rings (e.g., silicon carbide above 1000 ° C), but by the secondary seals necessary to compensate for axial shaft expansion.

According to the current state of the art, the use of a high-temperature mechanical seal with metal bellows as a secondary seal for the device described here and process temperatures up to 350 ° C, a reliable solution, since O-ring secondary seals on elastomer-based at temperatures above 270 ° C are no longer usable.

In order to ensure the proper functioning of the metal bellows of a mechanical seal, however, it must be ensured that this metal bellows located in the interior of the housing to be sealed is not confronted with liquids of very high viscosity and that no solid particles from the process fluid can settle in the folds of the metal bellows ,

Since in previous devices in the interior of the housing after the shaft bushings always equal to the area traversed by process liquid begins, due to the sometimes very high viscosity and entrained in the process liquid solid particles mechanical seals could not be applied.

the solution of the problem

For the device described in the invention, therefore, located on the insides of the shaft bushings special oil chambers were developed with a throttle tube surrounding the shaft through which the process partly partially highly viscous process fluid and solid particles from the process liquid are kept away from the sealing area.

By integrated in the eestungsgemäß housing design described oil chambers with throttle tube, can be used for the shaft seals, the current state of the art corresponding, high-temperature mechanical seals with metal bellows.

The housing of the device described in the invention also has ever in the shaft passage on holes on which are connected to the outside of the housing lines through which oil in these oil chambers on or deployed, and from the outside oil quality and oil level in the oil chambers can be controlled.

Since the oil chambers are closed by the mechanical seals to the outside and over the minimum gap of the throttle tube along the shaft connection to the process fluid, there is the same pressure with closed outer lines in the oil chambers as in the reaction chamber.

As a result, the gap between the shaft and the throttle tube of this oil chamber is minimal and there is the same pressure on both sides of the throttle ring, no or only an extremely low fluid flow takes place, even only small particles of solid particles can pass the throttle tube.

Small amounts of process fluid that can get into the oil chamber due to sudden pressure changes in spite of the minimum gap through the throttle tube, mix easily with the much larger amount of oil introduced into the oil chamber before the start of the process and thus also do not affect the Metal bellows of the mechanical seals.

Through outgoing pipes, the oil in these oil chambers can occasionally be checked for possible interference during operation, and replaced if necessary.

Via the lines leading to the outside and a metering valve, a minimal overpressure relative to the process fluid area, and thus an oil flow towards the interior, can be produced in these oil chambers, whereby a slow movement of oil in the direction of the housing interior the possibility of intrusion from process fluid into the oil chamber completely excludes.

In this application, which is not necessary under normal operating conditions, the required oil can be taken from the quota of purified oil, which, due to the process, is always fed into the process cycle anyway, which means that no additional expenses are incurred.

Inputs and outputs of the device

The device described in this invention, unlike the conventional design of the two-chamber liquid ring vacuum pumps not on each side of an input and an output, but only one input on one side and an output on the opposite side.

This ensures that the materials introduced the device not, as normally leave in a 2-chamber liquid ring vacuum pump on the same side chamber again, but on their way to the exit inevitably the entire impeller space so both chambers and a bottleneck in the Center, which leads to a desired extension of the residence time of the material in the device and to a desired increase in the output pressure, but also to a reduction of the flow rate.

Experiments have shown that under the aspect of the best possible process conditions, the advantageous effect of longer residence time at lower flow rate, over larger flow with less residence time outweighs.

Background of the improvement by increasing the shaft load capacity

The physical loads on the impeller and the shaft resulting from the original use of liquid ring vacuum pumps by air or gas extraction are many times exceeded in the case of devices for conveying liquids and solid particles by high friction and strong turbulence.

Since the freely bridged, not supported by bearing part of the impeller shaft, by the invention described housing shape of the device with lying outside the process fluid area shaft bearings, is longer than in previous versions, the housing shape for the mounted on both sides version ( FIG. 1 ), on both sides in each case two, with a distance from one another positioned shaft bearing, in order to ensure sufficient stability under the strong load of the impeller and the shaft by viscous liquids and solids.

In the housing version of the device with only one-sided shaft bearing ( FIG. 2 ), a larger diameter shaft is used compared to the double sided bearing version with the same impeller diameter, and the housing is designed so that the shaft bearings are positioned at a distance at least equal to but better than a multiple of the shaft diameter.

Both inventions described versions of the device, both the version with both sides of the impeller mounted shaft ( FIG. 1 ) as well as the version with unilaterally mounted shaft ( FIG. 2 ), can now by the integrated oil chambers with throttle tube protect the seal chamber, be equipped with, designed for industrial applications, virtually leak-free mechanical seals, and have the housing shape with arranged outside the process fluid range shaft bearings over the previously extreme service life by contamination of the shaft bearings ,

The illustration FIG. 1 shows an embodiment of the device with passing through the housing (2) shaft and on both sides of the housing two each outside the process fluid area arranged shaft bearing (1) and also on both sides of each oil chamber (7) with a throttle tube surrounding the shaft (8) for sealing off the sealing area from the process fluid area.

The illustration FIG. 2 shows an embodiment of the device with cantilevered shaft having on one side of the housing two, outside the process fluid area arranged shaft bearing (1), and in the sealing region of the oil chamber (7) with a surrounding the shaft throttle tube (8) for sealing the sealing area opposite the process fluid area.

List of reference numerals for the figures Figure 1 and Figure 2

1

shaft bearing

2

reactor housing

3

impeller

4

Mechanical seal

5

Process fluid input

6

Process liquid output

7

Oil-chamber

8th

choke tube

9

Reaction chamber 1

10

Reaction chamber 2

11

Mechanical seal coolant inlet

12

Mechanical seal coolant drain

13

Oil-chamber oil inlet

14

Oil-chamber oil flow

Claims (10)

Device for the thermo-catalytic decomposition of hydrocarbon chains, based on the basic principle of the liquid ring vacuum pump with a rotating in a housing impeller, and both sides of the impeller mounted shaft, characterized by a housing shape in which on both sides of each two spaced apart shaft bearing outside arranged in the region of the process liquid, and, in the inner region of the housing, directly after the two shaft passages, in each case one formed by partitions and a shaft surrounding the throttle tube oil chamber is located. Device for the thermo-catalytic decomposition of hydrocarbon chains, based on the basic principle of the liquid ring vacuum pump, characterized by a construction with only one side, on the drive side of rotating in a housing impeller double-bearing shaft, a housing shape in which the shaft bearing outside reachable from the process liquid Area is arranged, and, located in the interior of the housing directly after the shaft passage through a partition walls and a shaft surrounding the throttle tube shaped oil chamber. Apparatus according to claim 1, characterized in that
for the storage of passing through the housing shaft, on both sides of the housing, outside of the achievable by the process liquid housing portion each have two shaft bearings at a distance from one another or a plurality of shaft bearings are. Apparatus according to claim 2, characterized in that
for the storage of the shaft ending inside the housing, on the impeller-drive side of the device, outside the housing area reachable by the process fluid, two shaft bearings spaced from one another, or several shaft bearings. Apparatus according to claim 1, characterized in that
the, located in the interior of the housing, after the shaft passages, each formed by partitions and a surrounding the shaft throttle tube formed oil chambers, from the outside are filled and emptied. Apparatus according to claim 2, characterized in that
only one shaft bushing and only one seal is installed, and which, located inside the housing, after the shaft passage, formed by partitions and a surrounding the shaft throttle tube formed oil chamber, from the outside can be filled and emptied. Apparatus according to claim 1, characterized in that
the oil chambers formed by partitions and the shaft throttle tubes have holes through the housing wall to the outside, where lines can be attached outside. Apparatus according to claim 2, characterized in that
the, formed by partitions and a throttle tube surrounding the shaft oil chamber, holes through the housing wall to the outside, on which outside lines can be attached. Apparatus according to claim 1 and 2, characterized in that in a device with two, formed by the design of the impeller and the housing reaction Kammem, only one process fluid inlet for a chamber side is present or is used and only one process fluid output for opposite chamber side is present or used. Apparatus according to claim 1 and 2, characterized in that in a device in which not by the impeller and the housing form a chamber distribution in the housing is provided, the process fluid inlet and the process fluid outlet are both attached to the one existing chamber.

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