DE3246791A1 - METHOD FOR STIRLING LIQUIDS UNDER VACUUM, ESPECIALLY VISCOSIC SUGAR PRE-PRODUCTS OR. FROM THICKNESS - Google Patents

Description

Pedro Alamo Moreno December 9, 1982 IG / We

Infanta Mercedes 91

Madrid / Spain

Process for stirring liquids under vacuum, especially viscous sugar precursors or syrup

The present description, which is attached to an application for registration as an invention patent, relates to a "system for stirring liquids under vacuum with the help of compressed air injection ", the novelty of which is such that it is more than sufficient for the purpose pursued Advantages are provided in order to achieve the registration applied for, since the possibility of energy saving, Increase in productivity and better completion of the processes concerned is given. It represents lower energy consumption.

! 5 A brewing pan with a mechanical stirrer generally has a 20 - 50 HP motor, which works with 80 % of its nominal power during the boiling process, but causes a considerable decrease in the cos ψ of the electrical system with light load in the first part of the boiling process, while in the later course of the boiling the service life of the motor depends on the reliable function of the overcurrent relay due to the excessive power consumption.

When stirring with air, the consumption per brewing pan would be 5-6 hp. When it comes to energy consumption, there is a difference of approx. 10 - 30 HP per brewing pan, which is

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factory whose own production is limited and almost always in short supply is not to be underestimated.

It requires less investment because the brewing pan is mechanically Agitator almost always has a double-winding motor to use, depending on the consistency of the mass to work two different speeds. At the higher price of this type of motor comes the price of the reduction gear, this because of its high reduction ratio of 1,500 rpm to 40 - 60 of the stirring propeller must be big and expensive.

lo The stirring propeller is always a handcrafted one Part made of expensive metal that meets particularly strict specific conditions with regard to its casting quality must, and since it must be able to be dismantled to bring it to its place of use, it must be processed particularly carefully 15's.

The transmission shaft inside the brewing pan must be long, large in diameter and made of first class Be steel, made up of two or more parts connected by machined, expensive sleeves.

2o ^: inside the brewing pan it must have one or more special bearings that require automatic remote lubrication, apart from flushing with pressurized water, which prevents the mass from the brewing pan from penetrating into it and thereby quickly destroying it. The pressurized water that washes the bearing must be evaporated in the brewing pan, which requires a corresponding amount of steam.

The closure or the seal of the bearing at the exit of the brewing pan and at the top must be completely tight, which requires careful annual repairs, 30W0ZU the transmission must be lifted. Due to the location in the upper part of the brewing pan, expensive scaffolding is necessary; also the attachment of a fixed walkway above each brewing pan with agitator to To be able to remove the transmission and the engine.

-35 Caused a faulty seal during the sugar campaign uncontrolled ingress of air; for the

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speaking repairs, the brewing pan must be put out of operation for hours »

All of these circumstances are eliminated by the invention described herein.
Another advantage is the versatility "Mechanical stirring actually requires special brewing pans, which must have a central hole in their annular body in which the stirring propeller is mounted, and whose steam outlet and droplet recovery must be changed in order to be able to attach the drive unit.

On the other hand, you can stir the brewing pan with air and / or a portion of water vapor with little effort and a minimum In terms of investment, equip the most varied types of brewing pans with a tubular body with it: such with radiator, without center hole, with ring-shaped space

15 on the circumference, with a flat surface, or more or less inclined upper tubular plate, us «. It is sufficient to determine the shape of the brewing pan in each individual case and the insertion of the injectors for air and / or a part of water vapor at the most suitable places.

2o ^suc hen, in order to achieve an optimal stirring "The grain quality is improved"

It has been shown that in all sugar factories, stirring the mass decreases and increases the number of twin crystals considerably the single crystals. This means a

Reduction of the syrup inclusions between the surfaces of the twin crystals and keeping the syrup in the tips Angles that, in the case of the twin crystal, form the secondary crystals with the main crystal, resulting in a reduction of the ash content of the sugar crystals that are produced with the same

3o syrup is obtained in a brewing pan with or without stirring.

It is the same with the ICUMSA color of the sugar crystals. In the process described here, the ash is reduced by approx. 35 % and that of the color by 30 %. '

35On the other hand, whatever the way of stirring, it prevents the formation of excessive herds

Over-saturation and thus the formation of faulty grain in the course boiling, which improves the uniformity of the grain obtained.

We'll talk about the impact of this improvement later of uniformity during centrifugation, which increases the benefit even more.

The system also provides a reduction in the boiling time and steam consumption.

In fact, stirring the brew pans with air and / or a portion of water vapor ensures a reduction in the boiling time of more than 25 - 30 % » This effect can be seen more clearly in the case of brew pans for second and third products, ie those with a lower purity where the formation of bubbles Boiling is activated within the mass and the heat transfer is surprisingly improved, even at high viscosities.

In the case of the brewing pans, one can calculate that, due to the heat losses during the long residence time of the mass, the steam consumption is approx. 130 % of the water evaporated in them.

For every thousand tons of processed sugar beets, we can break down the steam consumption in the brew pans as follows:

Steam to evaporate and concentrate 107,700 kg

Steam used during the dwell time .. 32,230 kg

total amount of steam 140,000 kg

If the boiling time is reduced by 25 %, then, understandably, the steam consumption also decreases in the case of loss in the same proportion, ie the decrease in steam consumption is 8,075 kg.

In order to save steam, we mainly have to use Crystallization of products with low purity add the steam, which leads to the evaporation of the water that the Stove to maintain the boil - "the movement" in the brew pan is needed. This consumption we won't start, but you can easily estimate it at 700 kg per 1,000 t of processed sugar beet. Another advantage is the generation of a larger fluid

dity when the food to be cooked rises: a person skilled in the field of brewing pans knows that a brewing pan that has not been stirred must be lifted quickly because of the factory operation, must be lifted from below "closed", because if you lift them up, with which you get better crystals, it takes a lot of time to concentrate a full brew pan so that you can get syrup and the Must empty the brewing pan very liquid, which results in a low yield of crystals and a large amount of sugar syrup »

By stirring, both with air and mechanically, it is possible to close the brewing pan at the right moment close, giving a larger number of crystals and a drier syrup. From the formula for the yield of crystals:

■ ^ Yield of _ purity mass - purity syrup _in crystals % ~ 100 - purity syrup

it follows that by reducing the syrup purity from 79.5 to 78.5 % with a purity of the mass of 90.0, the yield of crystals increases from 51/22 to 53/49 % ,

'° which means an increase in the amount of crystals by 4.5%.

If you keep the food "liquid", i.e. less concentrated, you avoid the formation of new grains when lifting the Brewing pans, which then make it more difficult to separate the sugar from the molasses and increase the ash and color of the sugar « The system also brings about a reduction in sediment »

With a large part of the brew pans built, where the syrup has to cover the tubular barely to concentrate and crystallize, an extremely large "bottom sentence ", which causes extremely fine sugar crystals.

When stirring as described here, this sediment can be reduced considerably, since the syrup has the tubular The room is not completely covered, but this is due to the almost constant influx of additional air Fall is because the mass is on the upper tubular plate

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jumps and prevents local overheating and burning, which would be the case without movement.

This significant reduction in the boiling time allows in particular Felling a new working method, with which one can simultaneously achieve larger sugar crystals by you simply use a brewing pan for crystallization and in it a large "sediment", which is practically doubled is as big as normal, makes. As soon as the crystallization and clarification have taken place, half of this sediment is added into another brewing pan and bring both brewing

pans at the same time high or slightly delayed the one in relation to the other.

It is amazing how the syrup intake is facilitated. When the first product is boiling, it is practically normal to add the syrup to the brewing pan as soon as the food is high

Adds 15 from previous boilings, generally the purest or richest in syrup, so that the syrup is dried unc the crystal ratio of the mass is lowered, which results in greater fluidity and thus easier transport to the turbines.

Everyone knows, however, that it is not always easy to ensure that the syrup is quickly absorbed into the rest of the mass reach, whereby for a time there are two different phases. During this time the little crystals grow which are always in the syrup.

25If the brewing pan has a stirring device with air and / or a portion of water vapor, as is the subject of this description is, if you lift it up in more dissolved form, the mixture with the syrup is scraped off and you can achieve that the tiny crystals disappear. When boiling

3of products of lower purity are often added at the end of the Add a less pure syrup to dry out when the brew pan is concentrated or "sinks." closes ", which at the same time favors the fluidity of the mass. How quickly this syrup is absorbed is of the essence.

35 crucial to achieve optimal drying.

It also makes it easier to separate sugar and molasses. It has already been mentioned that any kind of stirring in a brewing pan prevents the formation of throat grains and twin crystals by avoiding places with particularly great supersaturation, with the result that the ratio of single crystals in the mass increases considerably and thus the uniformity of the crystals. When this mass with more uniform crystals comes into the centrifuge, a "cushion" or a crystal filter mass forms, the openings of which are not interrupted by smaller crystals, and the syrup flows easily through them = this makes it possible to load a turbine with mass to increase, to better utilize their capacity and at the same time to shorten the total duration of centrifugation _o

The same thing happens with the rinsing processes, which can be shortened without impairing the quality of the sugar, reducing the amount of water and thus even more syrups. "
We are particularly referring to ASEA centrifuges, which are practically used in Spain for the separation of sugar and molasses in primary products; these have a turbine cycle of approx. 145 seconds. Reducing this cycle by 7 seconds, which can easily be achieved when improving grain uniformity, means a 5/2% increase in performance in separating sugar and molasses in each machine; in addition, the mass feed per turbine is higher. In the case of continuously operating turbines, which are now very far used for the separation of products with low purity

3o are widespread, the greater uniformity of the Crystals make better use of machine capacity as the throughput is increased in bulk while the end product is being processed not impaired and the current limit of the motor is not reached »

Furthermore, a lower water consumption is achieved with Washing the sugar. The better uniformity of the grain

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reduces the amount of rinse water in the sugar grains. When centrifuging primary product mass, the manifold has of the ASEA centrifuges a flow rate of approx. 73 l / min. Simply reducing the 14 15 seconds normally required for flushing by 2 seconds means a reduction around

2 = 2.43 1 per turbine cycle,

which dissolves when the outer film of the crystal in

? 4 ^ 5
- jf% i - = convert 12.15 kg of syrup with 80 Brix.

Since approx. 800 cycles are required for 1,000 t of sugar beet, there is a reduction in the syrup of the primary product by

800 χ 12.15 kg = 9,620 kg of syrup. When separating intermediate products (secondary product, raffinate, Intermediate product, etc.) one can reduce the water in the continuously operating centrifuges achieve approx. 360 liters per 1,000 t of sugar beet; the same amount would be used in the centrifuges that separate the final mass, achieve. Expressed in syrup of intermediate products and in molasses with 83 respectively. 84 ° Brix we received:

Reduction in syrup, / - _n

of the 2nd product 017 ^{= 2} * ^{118 kg siru} P

Reduction in molasses, ^ _n

of the 3rd product jf ^ r = 2.250 kg of molasses

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This last case, this lesser amount of molasses, makes just over 0.1 kg of sucrose per 100 kg of sugar beets processed less that turns into molasses. Another benefit is the option in the factory grind more. The high investment that the sugar department demands in a factory has resulted in there are many factories which are forced to produce a large part of the syrup with high grinding and evaporation capacities to be stored in large containers in order to convert this syrup into granulated sugar after the sugar beet has been crushed with great expenditure of energy to convert.

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The reduction in cooking time per brewing pan corresponds to one equivalent expansion of the sugar department and therefore an increase in the crushing and processing capacity of sugar beets, which is achieved at low cost and with modest consumption.

This results in a better sale of the sugar.

Any improvement in the end product, in this case the reduction the ICUMSA color and ash content of the sugar along with better grain quality make it salable more easily or at a higher price.

Let us summarize what has been said so far about stirring the brew pans with compressed air and / or a portion of water vapor, so can be judged as follows:

1. The system requires a medium investment in the actual plant, which, depending on the conditions of each factory, is installed by installing a new vacuum pump and removal of the collector that transports the non-condensable products from the air pressure column to the vacuum pumps, can be expanded.

2. A reduction in energy consumption between a brewing pan with a mechanical stirrer and stirring by means of Air depending on the kW consumption.

3. Reduction of the investment: approx. 2-5 million pesetas per brewing pan for the mechanical agitator on one investment from 0.9 - 1, 3 when stirring with air and / or a part of water vapor according to the properties of the Installation.

4. The possibility of stirring every type of brewing pan that does not have room for a mechanical stirrer.

5. Reduction of steam consumption by 8,775 kg per 1,000 t of sugar beet, which amounts to the following amount when evaporating in boilers with 12 kg of steam per kg of heating oil, steam for heating the brewing pans of the second evaporation effect and a heating oil price of 23 Ptas./kg:
Savings in pesetas / day per 1,000 t of sugar beet ο 77c -1

χ -Jtt χ 23 = 8.410 pesetas / day.

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6. Due to better drying of the syrup at the purity point, the increase in crystals is estimated at 4.5 % for the first product, which increases from 51/22 % of the mass to 53.49 % , which is an increase of 2.27 kg of crystals means per 100 kg of mass. This logically requires a reduction in the syrup of 2.27 / 0.785 = 2.89 kg of syrup with 78.5 % purity.
This results in per 1,000 t of sugar beet / day

336,000 χ 2.89 / 100 = 9,710 kg of syrup, which when added to the 9,620 kg that is the

_lo syrup is reduced because of the lower water consumption when washing the white sugar, results in 18,330 kg, which would have been converted into the mass of the second products and thus 17,100 kg, which we on the other hand with a purity of 83.6 % and b9.7 % mass or Syrup 46 % crystals and

• ^ 54/080 = 67.5 would have resulted in the syrup of the 2nd product. Converted for chopping 1,000 t of sugar beet / day this would result in:

Reduction of the sugar crystals to be remelted 17,100 χ 0.46 = 7,860.

2 _O reduction syrup 2nd in 3rd product 17,100 χ 0.675 =

11,542.

The re-melting sugar crystals revealed dissolved in water or _juice; ;

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= 11,228 kg of remelted syrup,

which would come in the brewing pans of the 1st product and would result in 8,733 kg of mass with 90Ä Brix.

That means that the amount of mass of 336,000 kg per 1,000 t of sugar beet reduced to 327,270 kg, or one

3 decrease by 2.6 %. The 11,542 kg less syrup obtained, together with the 2,188 kg due to lower water consumption for the second product, would result in 13,730 kg syrup that would be produced less and would result in 11,828 kg less mass of the 3 · product at a concentration of 80 - 93 ° Brix.

35This means that the 71.00 kg mass is 3rd product processed at an assumed quantity of 71 kg per ton

Sugar beets are produced on

71,000 - 11,828 = 59,200 kg mass 3. would reduce the product »

On this less produced mass, if the purities of the mass were 73 % and of the final syrup 5 or the molasses 58.0 , we would have 35.7% crystals and 64.3 / 0.84 = 76.5 molasses, that means: reducing the to be refined
Crystals of the 3rd .................. 11,828 χ 0.357 = 4,222 decrease in molasses in the tank ". 11,828 χ 0.765 = 9,048.

If we add the 2,250 kg to this amount of molasses, which is increased by less water being used in the centrifuges of the 3 «product, that would result in 11,298 kg per 1,000 t of sugar beet that is not in the molasses tank reach.

At first glance, these calculations appear optimistic, since it was assumed that the total amount of water, which gets into the centrifuges dissolves sugar and does not dilute syrup, but it was not considered that a Reduction in mass production affects the syrup obtained in the lower purity product.

It is only intended to give a general idea of the importance of stirring the cooked mass in brewing pans with air and / or a part of water vapor for the technical balance of the results at the end of a sugar campaign can be; this balance ultimately decides on improvements and modifications in the time between two Campaigns. "

Essentially, there is a new experience, hitherto unknown due to its obvious incongruence, since one had never properly considered injecting air and / or a part of water vapor into an element in which a vacuum is created for certain processes.
In practice, it is carried out by attaching the appropriate mechanical elements, which are programmed according to the particular cycle and in different positions.

can be arranged in any way, preferably on the brewing units, these devices are adapted to the material to be processed so that pulses of air and / or parts of steam, the stirring process takes place in the desired strength and duration, with the result that the Completion of the product is going on very quickly. As can be seen from the above, the system is particularly versatile; there are no mechanical restrictions for application to a wide range of processes at the industrial level as well as on a smaller scale experimental procedure.

The parts used for the injection of the air and / or mixture with water vapor and their attachment to the for this purpose certain reactors are either already available on the market or what is very easy to manufacture the application of the system described on the one hand makes it extremely attractive and on the other hand it is robust Construction gives a long service life.

After the invention and a practical embodiment have been sufficiently described, it is noted that changes in details possible sirrd, unless they concern the basis.

Example: A graphic embodiment is shown in FIGS. 1-3, in which Pig I is a plan view of a reactor or the like. Pig 2 is a side view, partially broken away on the left, of the reactor or the like. and Pig 3s show in section, an individual representation with the connection of hoses in a Y-shape to an air nozzle. The reactor has a boiler, container or the like with an outlet connection 2 for the contents, a supply pipe 3 for the steam with an inlet connection 4, an input area 5 for the hot water with solenoids 6 shown as small circles, and distributor connections 7 via a control panel 8 the associated control lines 9 run to the distributor connections, see also the detailed illustration in Pig 3. By winding-like or serpentine-like

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applied windings is Io, which is designed as Kupferorhrschlange pipe 3 comprises concentric and ι from the voltage controlled Bedie- panel 8, and regulates the associated working medium. The entry of the air is shown in more detail at point 11 in FIG. This Pig 2 also shows the associated controlled valves, in particular non-return valves 12. The entry point for the hot water solenoid is denoted by 6a. Pig 3 shows, as an example of the injector component, a special injection nozzle 13, which passes through a suitable component of the reactor, has a non-return valve 15 in the Y-fork, continues into a flexible line or hose 16 or 16a and continues from here to a copper pipeline, for example, and from there ^ to the source of the working medium. To control the solenoids, a mechanical and / or electronic distributor with, for example, electrovalves,

2ο with associated timers, contactors, and relays. Through this especially the hot water exit is regulated. The number of injectors can be 5 to Io.

The invention is based on the drawn, using the example explained embodiment neither in detail nor in combination restricted; - depending on the individual case, modifications are possible with regard to the arrangement, the formation of the material and the like. Measures »that lie within the principle of the invention.

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Claims (9)

Pedro Alamo Moreno 9/24/1982 IG / wh Patent claims: ! / Method of stirring liquids under vacuum, in particular of viscous sugar precursors or thick juice, "characterized in that the stirring is carried out by continuous or pulsed blowing in, spraying in or injection of air and / or air-water vapor and / or water vapor takes place in such a way that inside a boiler, reactor or the like exposed to the vacuum. one or more flow-like Stirring flows are formed. 2. The method according to claim 1, characterized in that the stirring flows controlled or regulated by external intervention will. 3. Application of the method according to claim 1 or 2 on brewing pans in sugar production. 4. Device for performing one of the methods according to claims 1-2 or the application according to claim 3, characterized in that that the container, reactor or a brewing pan in its wall and / or in its the liquid to be stirred receiving interior has one or more tubular or nozzle-like injector components, the connections to a Driving unit jz.B. a source of compressed air, as well as further for the agent to be injected or injected. 5. Apparatus according to claim 4, characterized in that the injector components with a temperature control unit for the agent to be sprayed or blown in is provided. 6. The method according to any one of the preceding claims, characterized in that the blown or injected Means, e.g. air, brushing over the bottom of the reactor or the like. is performed so that the sediment is reduced. BATH ORIGINAL 7. The method according to any one of the preceding claims, characterized in that j that consciously one in a separate brewing pan high crystallization and formation of a large sediment carried out, then part, especially half of Transfer sediment into a second separate brewing pan and then both brewing pans essentially simultaneously or only be brought up with a slight delay relative to each other. 8. The method according to any one of the preceding claims, characterized in that the injector components in the interior or on the wall of the container or the like. adjustable, e.g. pivotable, so that they can be adjusted to areas during the stirring time large oversaturation of the syrup or the like. orientable are. 9. Device according to one of the preceding claims, characterized in that a collector between the compressed air column and there is the vacuum pump which conveys the non-condensables to the latter. BATH