DE102020000073A1 - Lying material separation column - Google Patents

Abstract

The invention relates to a material separation column that is designed and operated horizontally, characterized in that the material separation column contains a plurality of upright material separation devices which are inserted into the horizontal column, that packs (1) are used in the material separation devices and that the Liquid on the lower apex line flows to one side, but the gas flows opposite on the upper apex line.

Description

The invention relates to a mass separation column. Separation of substances is a recurring task in thermal-chemical process engineering. For this purpose, several different techniques are known which are also used on an industrial scale.

The absorbers contain granules in which certain substances are deposited and released again when the pressure or temperature changes.

The membranes work in a similar way to filters that hold back certain substances down to the molecular level.

The standing columns separate gas mixtures in the transition area from the liquid to the gas. However, the prerequisite is that the media of the substances to be separated have similar vapor pressure curves.

Design principle of a rectification column

These separation columns work on a simple principle. The liquid mixture to be separated is allowed to flow from top to bottom in a container. The liquid arriving at the bottom is boiled and the steam rises in countercurrent to the top. The direct contact of the two currents causes the exchange of substances. At the top of the separation column, a portion is removed as product, another portion is liquefied again and added to the column as washing liquid.

The columns, as the name suggests, are standing pressure vessels, have various types of built-in components in order to achieve the most intensive exchange of substances possible on the surface of the liquid while keeping the pressure drop in the system low. A distinction is made between the internals according to packed columns, tray columns, and packed columns.

Further essential criteria for this procedural component are the flexibility in system operation with fluctuating analyzes in the feed or in partial load operation.

Limits of the feasibility for standing substance separation columns

In the classic dimensioning of a separation column, it is the number of separation stages, e.g. the number of separation trays, the required tray spacing, the column diameter. This results in the following problems, such as construction height, assembly and stability of the column, plus the additional loads from earthquakes and wind.

As can be observed in industrialization and technology, plants are constantly getting bigger and bigger - and the tasks do not develop linearly.

It was around 1990 - for a petrochemical plant in South Africa (SA) were a - propylene-C3H6 / propane-C3H8 - mixture in a so-called. Separate C3 splitter. For this purpose, the tallest separating column of classic design was built. This was over 100 meters high, with a diameter of over 5 meters and weighed several 100 tons. This was designed and processed by Linde AG, manufactured in SA, pulled hundreds of kilometers across the country in 3 pieces, welded together on site and pulled and set up in one piece with the most powerful hoists available in the world.

There it stands free and without tension, and when there is no wind flowing towards it, motionless. The mode of operation also fluctuates with vibrations, since the liquid is then distributed unevenly on the dividing trays.

The limit of realization - maybe it can be even higher - maybe even bigger with a new design?

Design concepts of other structures that can be advantageous for the new horizontal separation column to be implemented.

Containers can be installed on the ground or in the trench, or buried in the ground. Liquefied natural gas, LNG (Liquid Natural Gas) is ^{stored under pressure in tanks with over 100,000 m 3} at -162 ° C. LPG (Liquid Petrol Gas) is transported by road, rail or water, stored in petrol stations overbuilt with traffic areas, used in private vehicles and in households. Whether pressureless or with overpressure, with or without insulation - all variants are in use.

Containers in prestressed concrete are not a novelty either. A wide, largely unused field of new opportunities, even ships have already been built. The concrete bodies reinforced with cold-tough steel can absorb surface temperatures down to -200 ° C.

The insulation required for this can be applied both inside and outside.

Status of the processing of the construction according to the invention

In the 1970s, the ethylene plant for BASF in Antwerp split an excessively high material separation column in the process engineering design. There were two pillars placed side by side. Liquid and gas were passed from one to the other.

The object of the invention is to propose a further material separation column.

The object is achieved according to the invention by a substance separation column with the features of claim 1. Preferred embodiments of the invention are specified in the subclaims and the following description, which can each represent an aspect of the invention individually or in combination.

Now, in the following (according to the invention) the height of the column is limited to a few meters. Many short standing columns are created and these are installed in a horizontal pressure vessel.

Description of the invention, the method and the device

During the exchange of substances, the closest possible contact must be established between the substances to be separated in the transition phase from the gaseous to the liquid phase in the entire process chain. The exchange of substances takes place on the surface of the droplets or the gas bubbles. The second criterion for an economical mode of operation is the pressure drop in the media caused by this device and its flow. Pressure drop means energy expenditure.

The proposed concept is based on the known packing columns. This is an operationally proven design that meets the criteria listed above.

A material separation column is a pressure vessel with procedural specifications, such as design pressure and design temperature, as well as the usual design data (environmental conditions). Since these are extremely large and heavy components, the manufacturing, assembly and transport situations must also be integrated into the construction.

The horizontal container is divided into several chambers - each section works like a vertical packing column. Liquid is distributed evenly over the top of the packing via a distributor base and gas flows in countercurrent from below to practice. Both streams hit an extremely large surface. The flowing gas stream enriches itself with the more easily evaporating components of the flowing liquid, at the same time the flowing liquid becomes depleted of these components.

The process is repeated in the next chamber.

The higher-boiling liquid collects at the bottom - the lighter gas collects at the top.

In both collection points, these media are discharged separately in their flow through non-return valves.

The operation using the example of a propane / propylae separation briefly shown in a few steps: inertize the system - fill with operating medium - raise to operating pressure - put the cooling and heating circuit into operation - the material separation begins to work - remove gas and liquid product .

Pressure, temperature, quantities and analyzes of the products can be set via by-passes to the chambers.

Stationary operation of the horizontal mass separation column

The so-called feed, a two-component liquid in the boiling state, flows from a system via a gas separator to the horizontal material separation column. The liquid flows to the first section of the material separation on the distributor base. The liquid is evenly distributed over the open face of the pack - excess liquid flows overboard along the walls to the lower apex of the container lying on the ground. This is where the liquid collects and is heated and boiled there. The steam rises in countercurrent through the packing. During this intensive contact, the two components enrich themselves with the constituent of the other - the exchange of substances takes place. The heating device in the lower apex, the "sump", is constantly in the liquid. This is ensured by the fact that the overflow of the liquid to the next chamber is positioned sufficiently high on the dividing wall.

In return, the rising gas is directed in the opposite direction via a non-return valve. At the same time, the remaining gas is condensed again with a cooling device. The condensate collects on the distributor base.

The analyzes for the gas and the liquid shift from chamber to chamber, approaching the required requirements.

Variable operation for the desired change in the product Outside the column, the parameters of the preliminary product in terms of quantity, pressure, temperature and analysis can be influenced.

In addition, there are also the options of introducing freely selectable feed quantities into the circuit, feeding in partial quantities at different sections of the material separation or turning the adjusting screw on the cooling and heating circuit.

In the following, the invention is explained by way of example with reference to the attached drawing using a preferred exemplary embodiment, the features shown below being able to represent an aspect of the invention both individually and in combination.

Features:

1. 1 Packung - die Ausführungsformen einer Packung als Füllung einer Stofftrennsäule darf als bekannt angenommen werden. Die äußere Form der Packungs-Einheit, eines Abschnitts ist stehend, oben und unten waagrecht und in dem Bereich des zylindrischen Behälters kreisförmig der liegenden Behälterwand angepasst und abgestützt.
2. 2 Verteilerboden - ist ein waagrecht aufgestelltes, rechteckiges Blech, nach allen Seiten mit einem wenige Zentimeter hohen Bord begrenzt. Die Bodenfläche weist regelmäßige Öffnungen auf, so dass die aufzugebende Flüssigkeit sich gleichmäßig auf die Stirnseite der Packung verteilt. Der Rest läuft über die Bordkanten, entlang der Behälterwand ohne wesentlichen Stoffaustausch nach unten.
3. 3 Rückschlagklappen - sind leichte Blechkonstruktionen. An einem Scharnier ist ein Deckel hängend angebracht, das mit dem Eigengewicht schließt und in einer Richtung durch die Strömung sich öffnet. Der Querschnitt der Öffnung für Gas (oben) ist ein Kreissegment, unten für die Flüssigkeit ein Rechteck. Die obere und untere Rückschlagklappe sind auch für die Funktion eines Mannloches für den Durchstieg längs der Säule konzipiert.
4. 4 Druckbehälter - siehe oben, ist entsprechend einer techn. Spezifikation und nach Länge und Durchmesser (Anzahl der Packungs-Abschnitte) optimiert.
5. 5 Packung-Abschnitt - als eigenständige Baugruppe an einer Trennwand. Die Trennwand ist Kreis-rund entsprechend dem Säulendurchmesser. An dieser wird eine komplett vorgefertigte Montageeinheit angebracht. Diese beinhaltet die Packung, die obere und untere Rückschlagklappe, den Kopfkondensator, den Aufkocher, den Verteilerboden, die Zuführung für die Kopf-Flüssigkeit. Zur Abdichtung der Wand, dieser Einheit gegenüber der nächsten, wird umlaufend eine Dichtlippe gegen die Strömungsrichtung angebracht. Der Packung-Typ und Packung-Proportion (Höhe /Querschnitt) ist nach verfahrenstechnischen Gesichtspunkten zu wählen. Maßnahmen zur Minderung der „Randgängigkeit“, darunter versteht man, wenn die Flüssigkeit anteilig an den Wänden abläuft, statt am Stoffaustausch teilzunehmen, sind zu diskutieren. Diese Problematik ist auch bei stehenden Packung-Säulen gegeben. Bei dieser Anwendung wird die Randgängigkeit vernachlässigt.

The figure shows a material separation column with the following features:

1. 1 packing - the embodiments of a packing as the filling of a material separation column can be assumed to be known. The outer shape of the packing unit, of a section, is upright, horizontal at the top and bottom and in the area of the cylindrical container is adapted and supported in a circular manner to the lying container wall.
2. 2 Distribution base - is a horizontally positioned, rectangular sheet, bordered on all sides by a shelf a few centimeters high. The bottom surface has regular openings so that the liquid to be dispensed is evenly distributed over the face of the pack. The rest runs over the beltline, along the container wall without any significant exchange of substances downwards.
3. 3 non-return valves - are light sheet metal constructions. A lid is attached to a hinge, which closes with its own weight and opens in one direction through the flow. The cross-section of the opening for gas (above) is a segment of a circle, below it is a rectangle for the liquid. The upper and lower non-return flaps are also designed to function as a manhole for passage along the column.
4. 4 pressure vessels - see above, is according to a techn. Specification and optimized for length and diameter (number of packing sections).
5. 5 pack section - as a separate assembly on a partition. The partition wall is circular according to the column diameter. A completely prefabricated assembly unit is attached to this. This includes the packing, the upper and lower non-return valve, the top condenser, the reboiler, the distributor base, the feed for the top liquid. To seal off the wall, this unit from the next, a sealing lip is attached around the circumference against the direction of flow. The packing type and packing proportion (height / cross section) must be selected according to procedural aspects. Measures to reduce the "marginal penetration", which means when the liquid partially runs off the walls instead of participating in the exchange of substances, are to be discussed. This problem also applies to vertical packing columns. In this application, the marginal accessibility is neglected.

6th

"Boilers" usually consist of finned heat exchanger tubes.

7th

"Head condenser", similar to reboiler.

8th

Feed gas separator, pressure vessel

9

Liquid product gas separator, pressure vessel

10

Gas-product-liquid separator, pressure vessel.

F.

Feed

FP

Liquid product

FS

Liquid flow

GP

Gas product

GS

Gas flow

MR

Heating return

HV

Heating flow

KR

Head cooling return

KV

Head cooling supply

Claims (1)

Device and method according to the preceding description, characterized in that 1 the material separation column (rectification) is designed and operated in a lying position. 2 that the horizontal mass separation column forms a pressure vessel. 3 that the liquid on the lower apex line flows to one side, but the gas on the upper apex line on the opposite side. 4 that the direction of flow of the liquid by so-called. Check valves is intended. The hinges on the upper edge of the opening secure the closing with their own weight. 5 that the direction of flow of the gas by so-called. Check valves is intended. The hinges on the upper edge of the opening secure the closing with their own weight. 6 that the non-return flaps of the liquid, the lower edge of which is arranged so high that there is sufficient liquid for the "reboiler" during operation. 7 that a pack is preferably used for the substance separation device. 8 that the material separation device consists of a partition, a packing, a liquid distributor base. 9 that the material separation column consisting of a plurality of upright material separation devices are inserted into the horizontal column 10 that the individual material separation devices attached to a circular disk have a sealing lip that seals the gas and liquid flow in the direction of flow of the liquid. 11 that the distributor base has openings and a circumferential rim to ensure a constant liquid level. 12 that the dimension of the distributor base has a sufficient gap around the circumference to allow the gas to pass through. 13 that the individual material separation devices have a "top condenser" to condense the flowing gas 14 that the individual material separation devices have "boilers" to evaporate the liquid that collects at the lower apex. 15 that a gas separator is attached before the entry of the so-called feed, ie the mixture. 16 that a liquid separator is attached at the outlet of the gas product. 17 that a gas separator is attached at the outlet of the liquid product. 18 that the material separation column lies in a heated bed of sand and the upper side along the apex is at least protected against solar radiation, and is even better cooled. 19 that in order to reduce the disruptive accessibility to the edges, deflector plates are attached to the walls of the pack. 20 that the lying pressure vessel is slightly inclined in the longitudinal axis to one side in order to empty it through a natural gradient. 21 that at the lower apex of the partition wall has a small opening for the drainage of the residual liquid.

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