LT5866B - Device and method for loading of solid granules to vertical room - Google Patents

Abstract

The device according the invention can be used for loading of vertical rooms, for example to load reactor tubes for hydrogen production with catalyst. Device is comfortable to use for loading reactor, at which feeding holes is no many place. Particles of disseminate catalyst are stopped by the cross flow of air, which is pumped to the device from environment. At the same time exhaust flow is filtered from catalyst particles and environment is protected against carcinogenic substances. Determination to pump the air makes constant falling velocity of particles during the filling process. Flow meter and automatic valve controls and maintains a constant flow. Integrated camera allows in real time to control catalyst loading quality and to choose optimal speed of loading rate.

Description

The invention relates to chemical or physical processes (for example, catalysis) which are carried out in vertical tubular reactors filled with solid particles. Specifically, the present invention improves existing facilities for solid catalyst particle filling of such vertical reactors and can be used in a variety of chemical technology processes, such as hydrogen production.

BACKGROUND OF THE INVENTION

Hydrogen production plays a significant role in today's chemical industry. Large quantities of hydrogen are needed in fertilizer and oil refining processes, hydrocracking of intermediate petroleum products, and in the production of ammonia and methanol, which are used in large quantities in fertilizers, plastics, paints, etc. in the industry. Currently, the main process by which hydrogen is produced is the conversion of methane to water vapor. Recent advances in catalyst production make it possible to use not only methane but also its analogs in natural gas as feedstocks. Hydrogen is produced in special reactors filled with a process accelerating catalyst. The reactor consists of several tens to thousands of vertical tubes of high temperature (above 700 ° C) with an internal cavity of 10-15 cm in diameter. Hydrogen production efficiency is determined by many factors, one of which being the quality of reactor-filled catalyst. An essential requirement is the uniformity of filling of the catalyst. These vertical pipes (up to 10-15 m in height) can only be filled from above. This condition requires such a technical solution that the catalyst beads (for example brittle ceramic beads up to 2 cm in diameter) do not decompose during loading into the reactor so that the entire volume of the tube is filled evenly (without air gaps) and the filling process itself is as fast as possible. Fill uniformity is usually checked by measuring the resistance of the catalyst bed to compressed air over the entire height of the tube. The measurement result is called the differential pressure (denoted as Δρ, units of pressure), after the catalyst is charged to all reactor tubes, their Δρ is measured and the percentage by which each measurement result differs from the average is measured. The usual standard is ± 5%. If the reading is outside the tolerance range, the catalyst must be unloaded and re-charged or other measures taken. This wastes time and catalyst stocks. However, the greatest loss of production is at risk if the air gap in the catalyst bed and / or the Δρ of some pipes is too high due to poor quality loading. In hydrogen production, for example, this would lead to localized overheating or overheating of the entire pipe, respectively, since incomplete or weaker endothermic reactions would no longer be sufficient to maintain optimal temperature. In this case, it is necessary to stop the production because failure to detect the overheating in time would threaten reactor explosion and huge losses.

Several systems have been designed and used to fill vertical reactors with catalyst beads. One of the oldest, but probably still very widespread, method is sock loading [Handbook of Petroleum Processing, David S J Jonah; Peter P. Pujado, Springer (2006)]. Technically, such loading is accomplished as follows: A 1-2 m long sleeve-shaped bag is filled with catalyst and its lower end is folded so that when the bag is inserted into the tube, some of the material is squeezed between the bag and the tube. The upper end is bound by a rope and is used to lower the bag to the bottom of the tube or to the surface of the catalyst already charged. Then, with a sudden motion, the bottom end of the bag opens and the catalyst disintegrates.

This method has many disadvantages:

- when lowering the bag, the catalyst often bursts prematurely and collapses when dropped;

- requires a great deal of physical labor;

- is the slowest of the available methods;

- the catalyst drops immediately in large quantities, so that there is no uniform distribution of air in the filler;

- very poor Δρ measurement results in the reactor tubes being reloaded.

A number of other catalyst loading methods are known and patented by various companies (US 3749258, EP 0548999, WO02004 / 096428, WO02007 / 109442, EP 1752210, EP1749568, WO02007 / 141419, WO02007 / 039764, etc.) using various means and devices. to alleviate the fall of catalyst pellets.

For example, it is known from catalyst manufacturer Haldor-Topsoe (DK) SPIRALOAD technology disclosed in EP1283070 et al., Which introduces plastic spiral cylinders of the appropriate diameter into the reactor tube about 2 m in length and rolls the helix downward from the top. As the catalyst level rises, the coil is withdrawn from the tube and the upper protruding part is disconnected. The catalyst is then scraped further and the procedure repeated until the desired filling height is reached.

This technology is superior to the first, but also has disadvantages:

- this method is not fast;

- Relatively large equipment needs per loader team;

- intermittent charging, which results in unevenness of catalyst bed;

- when the coil is long (the tube is initially empty, the catalyst rolls to a depth of 11-14 meters), the catalyst particles roll much faster than at the end of the charge, rolling to a depth of 2 to 5 meters, and therefore break more often;

- Long-term friction on solid surfaces abrasion catalyst particles and generate dust which is undesirable after starting hydrogen production.

Patent application WO02004 / 096428 describes a so-called UNIDENSE technology using a steel rope with flexible brushes perpendicular to the rope. When the catalyst falls from above, the brushes effectively stop its particles from falling until they fall to the bottom. As the catalyst layer rises in the tube, the rope is pulled up. A metal balance is attached to the bottom of the rope, allowing the rope worker to feel when the catalyst rises to the bottom of the rope. This method of loading is efficient and requires little equipment and labor.

Its disadvantages are:

- As the work progresses, workers no longer feel when the pound touches the surface of the catalyst, so often part of the rope is filled with a significant amount of catalyst pellets. The release of the rope requires the use of non-standard means and is time consuming;

- Several teams of workers are working at different speeds when filling pipes in the same reactor. Volatiles are formed in the catalyst layer as the flashing occurs faster than the optimum in the particular case. This results in undesirably large Δρ fluctuations;

- Lint brushes break continuously and catalyst particle drop is less and less slow. The process has to be stopped and broken brushes replaced. However, most workers do not notice this failure and continue to charge the catalyst using a rope that has already broken some of its brushes. As a result, the catalyst beads reach the bottom of the tube with unstoppable falling and part of it breaks;

- Continuous contact braking (brushing) wears out catalyst particles and generates a lot of dust;

- Occasionally, the rope breaks, then wastes a lot of time pulling the ruptured part from the catalyst-filled tube.

The known UNILOADER technology [VV02009 / 021723, etc.] is a slightly more mechanized version of UNIDENSE. The catalyst charge rate is controlled by varying the speed of the machine's conveyor, and the rope is automatically pulled at a speed that matches (usually exceeds) the catalyst bed in the riser. These improvements avoid some of the disadvantages mentioned above, but most of them remain because the same principle of rope is used. In addition, due to the fact that the wire rises faster than the catalyst bed, it is often the case that a considerable distance is left for the catalyst particles to fall unstable. There are no arrangements for monitoring the distance between the bottom of the rope and the surface of the catalyst.

The closest analogue to the prior art is the method and apparatus for loading particles into a tubular reactor tube as described in patent RU 2180265 (EP 1374985). The device described in this patent has a pellet feed device and, in its central part, accommodates a flexible hose in the downstream tube, the upper end of which is fixed on a drum and connected to a gas flow source. According to this patent, when the catalyst particles drop from the top into the tube at a uniform rate, the particle drop rate is counteracted by countercurrent flow of gas to the bottom of the tube through a flexible hose that is raised upwardly in the catalyst bed to rise. The catalyst particles fall into the gap between the tube wall and the lifting hose that is wound on the drum.

This analogue has a number of disadvantages.

When gas (air) is blown into the empty reactor tube, a portion of the blast flow is freely dispersed through the gas-permeable bottom of the tube. When the catalyst covers the bottom of the tube, the flow of the allowed gas flows almost entirely upward, changing the rate of falling particles from the top, maybe even the direction of movement. As a result, this method does not ensure uniform particle loading.

However, the main disadvantage of the known technique and device is that a large amount of dust is blown from the mass of catalyst particles by blowing the gas (air) which enters directly into the environment through the top of the reactor tube. The catalyst is rich in toxic and carcinogenic substances (mainly nickel oxide) and usually requires up to 30 people to work in a saturated environment. As a result, there is a serious environmental and human safety problem.

The analogue device is impractically large (especially the hose lifting and winding unit) and difficult to move from one reactor tube to another, often making it even impossible to use the device in reactors that do not have enough space at the top. In addition, without the ability to monitor the emerging catalyst bed surface, it is not possible to select the optimum loading speed and ensure full control over the loading quality.

Thus, the state of the art of the known art does not eliminate the problem of catalyst dust in the working environment and does not control the relationship between hose lift rate, loading rate and quality.

The essence of the invention

To solve the above problems, a method for loading the granular catalyst material into vertical containers, defined by the set of features of claims 1-4 of the invention, and a device for carrying out this method, is defined by the set of features of claims 5-10.

A method of loading solid pellets into vertical containers is proposed, in which, when the pelletized material is poured from above, the pellet drop velocity is suppressed by a counter-flow of gas. The method is characterized in that the counter-flow of gas is formed by forming a channel open to ambient pressure inside the vertical container and applying a reduced pressure in the container cavity around the formed channel. The open channel for ambient pressure is made like a telescopic tube; optimizes backflow by adjusting the gas suction rate in the tank cavity around the telescopic tube and continues to automatically maintain it constant throughout the charge.

In an optimum embodiment, the blown air is additionally cleaned of dust by adjusting the suction air flow rate.

Selects the optimum loading speed and controls the loading quality by visually observing the resulting solid pellet layer.

The device for loading solid pellets into vertical containers according to the invention comprises a branch body which in its central part is provided with a conduit for supplying gas, for example air, to a vertical container where the body is first connected to a pellet feeder and the second branch is connected to gas. such as an air flow regulator. The device is characterized in that the duct is made as a telescopic tube, the upper end of which is open to ambient pressure, the first branch is located in front of and below the second branch, and the body has a lower part adapted to be tightly connected to the loadable vertical vessel.

Inside the telescopic tube is a recessed rope that can move vertically by winding it on a reel of lifting mechanism, where a video camera is mounted at the bottom end of the rope.

In one embodiment of the device, the vertical capacitance is a reactor tube, the device extends the telescopic tube length not less than the reactor tube height and, depending on the pellet layer level, the telescopic tube length is adjustable from fully extended tube reactor tube length to full reaction tube , including the telescopic tube sections from the bottom in turn.

The air flow control device of the present invention is a pipe with a valve connected to a flow meter, wherein the lower end of the flow control device is connected by a second branch to the connection and its opposite end is connected to a pump. The flow control device is not necessarily removable and has an additional dust filter.

In an optimal embodiment, the device of the invention further comprises a control device connected to a video camera, an air flow meter and a drum of a pellet feeder.

Brief description of the drawings

The invention is illustrated in the drawings, in which:

FIG. 1 is a central view of the central portion of a device for loading granular material into vertical containers. Telescopic tube included in upper section; flow regulator and pellet feeder not shown.

FIG. 2 is a general view of the flow control device.

FIG. Fig. 3 is a view of an inventive device prepared for loading granular material into an empty reactor vessel. A flow control device and a pellet feeder with a drum are shown.

FIG. 4 - Dependence of recommended initial air flow Q on reactor tube diameter.

Detailed Description of the Invention

The device for loading solid pellets into vertical containers (Fig. 1) has a housing (1) with side branches (3, 5); in its central part, the housing accommodates a channel (2) for supplying gas, such as air, to a vertical vessel. The housing (1) is connected via the first branch (3) to the granular material supply device (4) (Figs. 1 and 3), and via the second branch (5) to the air flow control device (6) (Fig. 2). ). The channel (2) is made as a telescopic tube, the upper end of which is open to ambient pressure, the first branch (3) being arranged in front and below the second branch (5), the lower part of the housing (7) (Fig.1) capacity. The vertical capacity is the reactor tube (8) (Fig. 3), and the telescopic tube (2) unfolded is optimally longer than the height of the reactor tube (8). Depending on the pellet layer level, the length of the telescopic tube is adjusted from the fully extended reactor tube to the upper length of the telescopic tube section in the loaded reaction tube by including the telescopic tube sections from the bottom.

The telescopic tube of the device consists of 10-12 thin sections (up to 1 mm thick) of sliding (extendable) sections of lightweight material, such as aluminum or rigid plastic; the tube has a diameter of, for example, about 7 cm at the top and about 5 cm at the bottom (i.e., the difference between the diameter of the tube at the top and the bottom should not exceed 2-3 cm).

When the telescopic tube is fully lowered (fully extended), its overall length can reach up to 15 m.

Inside the telescopic tube (2) is a recessed cable (9) which can move vertically, the lower end of which is fixed in the center of the central telescopic tube section along with the video camera (11). The telescopic tube, when lowered, expands under the effect of gravity and is lifted (sections pushed) by winding the inside rope (9) onto the lifting coil (10). The top of the telescopic tube is covered with a grille that prevents foreign objects from entering the reactor and allows only air to pass through.

Said air flow regulator (6) (Fig. 2, Fig. 3) is a pipe with a valve (12) connected to an air flow meter (13). The lower end of the flow regulator (6) is connected by a connecting part (14) in the second on the branch (5), and its opposite end is connected to an industrial pump (not shown).

The flow control device (6) may be (not necessarily) removable and additionally has a filtering means (15) which prevents the loading of pellet debris as well as residual processes (soot, etc.) from the reactor tube walls.

In an optimal embodiment, the device of the invention has an additional control device (16) connected to three controlled positions: a distance sensor or video camera (11), an air flow meter (13) and a drum of a pellet feeder (4).

The device of the invention also operates in the process of loading solid pellets into vertical tanks by loading the hydrogen reactor with catalyst pellets as follows:

Prior to starting the loading work, it is necessary to make sure that the old catalyst has been removed from the reactor, that the reactor pipes are empty and undamaged. The old catalyst is removed by injecting the pump hose into each pipe and suctioning out the catalyst residue.

In order to insert the device of the invention into the reactor tube, it is necessary to make sure that the lower part (7) of the device body corresponds to the diameter of the reactor tube (8) to be filled; for this purpose, the lower part (7) is made of uniformly decreasing diameter.

This lower part is best mounted to the center of the casing and is tightly fitted into the reactor tube. Then, the first lower branch (3) is fitted with a catalyst pellet feeder (4) with a drum and the second branch (5) with an air flow control device (6). The control apparatus (16) is connected to the telescopic tube video camera (11), to the catalyst pellet injection drum (4) and to the air flow control device (6). Activate the video camera (11) and observe the telescopic tube (2) being lowered (extended) through the display of the control device (16). According to the data in the graph (Fig. 4), the flow of air is adjusted and adjusted depending on the reactor tube diameter (within 10% error). Fill the catalyst pellet tank (4) and start the pellet feed drum. The catalyst pellets begin to fall down, slowing down by the rising flow of suction air. The camera (11) observes the pellet drop and the rising catalyst bed. The control device (16) determines the upward (downward) speed of the telescopic tube (2) and, accordingly, the rotation speed of the spool (10). The telescopic tube (2) is raised (pushed) by winding a rope (9), which is fed inside, on the reel (10) of the lifting mechanism. Initially, the airflow, the intensity of which depends on the reactor diameter, is plotted (Figure 4). By monitoring the loading process by a specialist via a sensor screen, the control apparatus (16) adjusts the airflow and catalyst rash rate for an optimum rate-to-quality ratio. The automatic valve (12) helps maintain a constant flow of suction air. Once the correct charging parameters have been set, they are not changed during the charging process.

After loading the required amount of catalyst into the reactor tube (8), the telescopic tube (2) is raised (pushed) and air suction stopped. The device of the invention is then moved and inserted into the adjacent empty reactor tube (8b) (Fig. 3) without removing the devices (4, 6) located in the side arms (3, 5) of the housing (1). The procedure is repeated - the telescopic tube (2) is lowered (folded), air suction and other reactor loading operations described above are monitored on the control device (16) screen while watching the broadcast image of the camera (11).

The main purpose of loading solid pellets into reactors such as hydrogen is to evenly fill the reactor tubes with catalyst. Work must be done safely, quickly, without damaging the environment, and save on catalyst stocks. It is very important that the fine particle particles formed by the process of the invention are not blown from the reactor tube to the human working environment by generating a saturated atmosphere of harmful dust, but passes through the filter with the suction air flow and are contained therein. Because the coil is wound only with straight rope, this unit is at least 5 times smaller than UNIDENSE technology and more than 10 times smaller than the analogue of RU 2180265 hose reel.

Some of the comparative efficacy parameters of the invention are shown in the table below.

Table

Comparison of the efficiency of different loading methods

'Socks method " UNIDENSE WO02004 / 096428 RU 2180265 Offered invention Loading quality * 50% 80% 90% 100% Relative loading speed 25% 100% 100% 100% Relative dust pollution of the working environment 70% 30% 100% 10% Real-time monitoring of the emerging catalyst bed + The likelihood that the charging process will be stalled (through 1 reactor tube) 30% 10% 0% 0% Active removal of carcinogenic catalyst dust + Fast-wearing parts (need to be replaced during operation) + DP " -10% -5% -1% not more than 1%

* uniformity of catalyst bed density throughout the reactor tube; uniform layers in all pipes; minimum amount of damaged catalyst particles.

** DP Differential Pressure When the pipe is loaded with catalyst, the flow of compressed air is flushed through the bed and the bed resistance (in units of pressure) is measured. The DP (highest deviation from the mean of results) should be as low as possible.

The table shows that, compared to the prior art, the technical solution of the present invention ensures a high quality of catalyst filling process, safe and healthy working conditions. In addition, charging speeds up as there is no need for frequent replacement of worn machine parts. The air flow regulator is removable, allowing convenient and quick replacement of the filter medium.

Claims (10)

DEFINITION OF INVENTION 1. A method of loading solid pellets into vertical containers, wherein the pelletizing material is suppressed by a counter-gas flow, which comprises forming a counter-gas flow through an open pressure channel inside the vertical container and applying a reduced pressure in the container cavity around the formed container. channel. 2. A method as claimed in claim 1, characterized in that the open-to-ambient pressure channel is made as a telescopic tube and that the optimum counter flow is formed by adjusting the gas suction velocity in the container cavity around the telescopic tube and automatically maintaining it constant throughout the loading time. 3. A method as claimed in claim 1 or 2, wherein the gas is air and, by controlling the air suction rate, the blown air is additionally cleaned from solid pellet dust. 4. A method according to any one of the preceding claims, characterized in that the optimum loading speed is selected and the loading quality is controlled by visual observation of the resulting solid pellet layer. A device for loading solid pellets into vertical containers as defined in any one of claims 14, comprising a housing (1) with branches (3,5) having a central channel (2) for supplying gas, such as air, to a vertical container, the housing (1) being connected to the first branch (3) with a pellet feeder (4) and the second branch (5) being connected to a gas, e.g. air flow regulating device (6), characterized in that the channel (2) is made telescopic the pipe having its upper end exposed to ambient pressure, the first branch (3) being disposed in front of and below the second branch (5), and the housing having a lower part (7) adapted to be tightly connected to the vertical load capacity. 6. A device according to claim 5, characterized in that the vertical volume is a reactor tube (8), the telescopic tube (2) extended by the device is at least the height of the reactor tube (8) and, depending on the pellet layer level, the telescopic tube adjustable from fully extended in the empty reactor tube to the upper length of the telescopic tube section in the loaded reaction tube, including the telescopic tube sections in turn from the bottom. 7. Apparatus according to claim 5 or 6, characterized in that a telescopic tube (2) is provided with a rope (9) which is movable vertically by winding it on a lifting reel (10), wherein a video camera (9) is mounted at the lower end of the rope (9). 11). 8. A device as claimed in any one of claims 5 to 7, wherein said air flow control device (6) is a tube with a valve (12) connected to a flow meter (13), wherein the lower end of the flow control device (6) is coupled. part (14) is sealed in the second branch (5) and its opposite end is connected to the pump. A device according to any one of claims 5 to 8, characterized in that the flow control device (6) is optionally removable and further comprises a filtering means (15) which retains dust. A device according to any one of claims 5 to 9, further comprising a control device (16) connected to a video camera (11), an air flow meter (13) and a drum of a pellet feeder (4).