DE102022205801A1 - IMPROVED CARBONATION PROCESS AND APPARATUS FOR IMPLEMENTING SAME - Google Patents

Abstract

The present invention relates to a method for producing a carbonation product from a carbonation educt and a device for producing a carbonation product from a carbonation educt, particularly suitable and designed for carrying out the method according to the invention.

Description

The present invention relates to a method for producing a carbonation product from a carbonation educt and a device for producing a carbonation product from a carbonation educt, particularly suitable and designed for carrying out the method according to the invention.

Carbonation plays a central role in the technological process steps of a beet sugar or sugar cane sugar factory or a raw sugar refinery. The carbonation usually includes a first carbonation step and a second carbonation step. Carbonation is a purification step in juice purification, in particular sugar raw juice purification, be it a sugar raw juice from beets or sugar cane, or sugar refining, in particular a raw sugar solution. Before carbonation, the sugar raw juice or the raw sugar solution used for carbonation is obtained by extraction from sugar beets, in particular beet pulp, or sugar cane or by dissolving raw sugar in water and subsequent preliminary and/or main liming, also referred to as alkalinization. During pre-liming and main liming, the extracted raw sugar juice or raw sugar solution is mixed with lime milk, i.e. calcium hydroxide dispersion in water. This leads to flocculation of suspended solids contained in the extracted raw sugar juice or raw sugar solution. Alkalization results in an alkaline raw sugar juice or an alkaline raw sugar solution. The primary liming results in a primary liming alkalinity of approximately 0.6 to 1.2 g CaO/100 ml in the sugar raw juice or raw sugar solution, which corresponds to a pH range of pH 12 to 12.8 at 20 °C.

The carbonation is carried out with the alkaline raw sugar juice or the alkaline raw sugar solution obtained in this way. In the first carbonation step, carried out in a first carbonation container, the calcium hydroxide dispersion added in excess in the main liming and present in the alkaline raw sugar juice or the alkaline raw sugar solution is neutralized by introducing freshly produced lime kiln gas, i.e. a gas containing carbon dioxide, the alkaline raw sugar juice or the alkaline Raw sugar solution is neutralized to a pH end point of approximately 11.4 to 10.8 at 20 ° C, which corresponds to a final alkalinity of approximately 0.06 to 0.1 g CaO/100 ml, and the calcium hydroxide is precipitated as calcium carbonate becomes. The precipitated calcium carbonate, particularly precipitated in the form of calcium carbonate crystals, has an active, positively charged surface. Without wishing to be bound by theory, the precipitated calcium carbonate, in particular in the form of calcium carbonate crystals, is able to exert a cleaning effect through the adsorption of precipitated colloids and other non-precipitable non-sugar substances due to the active surface. At the same time, the precipitated calcium carbonate, in particular calcium carbonate crystals, acts as a filter aid. In the second carbonation step, carried out in a second carbonation container, the alkaline raw sugar juice or the alkaline raw sugar solution is brought in by introducing freshly produced lime kiln gas to a pH end point of approximately 9.4 to 8.6 at 20 ° C, which is a final alkalinity from approx. 0.005 to 0.015 g CaO/100 ml, neutralized and the calcium hydroxide is precipitated as completely as possible until the optimal alkalinity is reached as calcium carbonate, in particular in the form of calcium carbonate crystals.

CO ₂ gas utilization levels, i.e. the utilization rates of the CO ₂ content in the lime kiln gas, can have a maximum value of approximately 90 to 95% in the first carbonation step and a maximum value of approximately 70 to 75% in the second carbonation step using novel carbonation containers from the prior art to reach. Therefore, despite comparatively high CO ₂ gas utilization rates, a significant portion of the CO ₂ released in the lime kiln is still in the so-called carbonation vapor, i.e. the exhaust gas from the respective carbonation step. The degree of CO ₂ gas utilization in the carbonation steps depends primarily on the alkaline sugar raw juice level or alkaline raw sugar solution level, temperature, mixing, alkalinity of the sugar raw juice or raw sugar solution and CO ₂ content in the lime kiln gas. It is known that as the CO ₂ content in the lime kiln gas decreases, the gas utilization rates in the carbonation steps decrease and the CO ₂ losses increase. This can be observed, for example, when switching from a coke-powered lime kiln to a gas-powered lime kiln. The resulting reduction in the CO ₂ content in the lime kiln gas and the associated reduction in the degree of gas utilization, especially in the second carbonation step (CO ₂ content of the exhaust gas approximately 15 to 25% by volume based on the total volume of the exhaust gas) can result in a CO ₂ - Deficiencies in sugar production or sugar refining and lead to significant fluctuations in the operation of the carbonation steps. The lower the overall gas utilization ratio or the higher the CO ₂ losses from carbonation, the more CO ₂ is released into the environment, which leads to environmental damage and, in particular, promotes the greenhouse effect.

Therefore, the technical problem underlying the present invention is to overcome the aforementioned disadvantages. In particular, the technical problem on which the present invention is based is to provide methods and means that make it possible to increase the CO ₂ total gas utilization rate of a carbonation, in particular a carbonation in a beet sugar or sugar cane sugar production process or in raw sugar refining. The technical problem is preferably to provide processes and means that make it possible to reduce the CO ₂ emissions of a carbonation, in particular a carbonation in a beet sugar or sugar cane sugar production process or a raw sugar refining process. In addition, a technical problem of the present invention is to provide such methods and means that are inexpensive, environmentally friendly and easy to handle.

1. a) Alkalisierung von einem Carbonatationsedukt unter Erhalt eines alkalischen Carbonatationsedukts und
2. b) Carbonatation des alkalischen Carbonatationsedukts umfassend einen ersten und mindestens einen weiteren Carbonatationsschritt bl) und b2) unter Erhalt des Carbonatationsprodukts, im Rahmen derer jeweils ein CO₂-angereichertes Carbonatationsgas in das alkalische Carbonatationsedukt eingeleitet und ein CO₂-abgereichertes Abgas ausgeleitet wird, gekennzeichnet durch
3. c) Einleiten mindestens eines Anteils des CO₂-abgereicherten Abgases des mindestens einen weiteren Carbonatationsschritts in das alkalische Carbonatationsedukt vor oder während dem ersten Carbonatationsschritt, bevorzugt vor dem ersten Carbonatationsschritt.

The technical problem is solved by the teaching of the independent claims, the dependent claims and the teachings of the description, in particular by a process for producing a carbonation product from a carbonation educt, comprising the process steps:

1. a) Alkalization of a carbonation educt to obtain an alkaline carbonation educt and
2. b) Carbonation of the alkaline carbonation educt comprising a first and at least one further carbonation step b1) and b2) to obtain the carbonation product, in the course of which a CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt and a CO ₂ -depleted exhaust gas is discharged, characterized through
3. c) introducing at least a portion of the CO ₂ -depleted exhaust gas from the at least one further carbonation step into the alkaline carbonation educt before or during the first carbonation step, preferably before the first carbonation step.

Accordingly, it is provided according to the invention that in a first process step a) a carbonation educt is alkalized, in particular by introducing alkaline substances, in particular calcium hydroxide, in particular milk of lime, in particular in a preliminary and/or main liming, and an alkaline carbonation educt is obtained. The alkaline carbonation educt therefore has alkaline substances introduced by the alkalinization, in particular calcium hydroxide. With the alkaline carbonation educt obtained in process step a), a carbonation is carried out in a process step b) and a carbonation product is obtained. The carbonation carried out in process step b) comprises a first carbonation step b1) and at least one further carbonation step b2). At least two carbonation steps b1) and b2) are therefore carried out in process step b).

During each carbonation step, a CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt and a CO ₂ -depleted exhaust gas is discharged from the resulting alkaline carbonation intermediate or carbonation product. Without wanting to be bound to theory, by introducing the CO ₂ -enriched carbonation gas into the alkaline carbonation educt, CO ₂ of the CO ₂ -enriched carbonation gas reacts with the alkaline substances present in the alkaline carbonation educt due to the implementation of process step a), in particular calcium hydroxide, to calcium carbonate, the calcium carbonate precipitating as a solid, in particular in the form of calcium carbonate crystals, from the alkaline carbonation educt and an alkaline carbonation intermediate or carbonation product is obtained. In particular, the reaction of CO ₂ with calcium hydroxide to form calcium carbonate lowers the pH of the alkaline carbonation intermediate or carbonation product compared to the alkaline carbonation reactant. The precipitated calcium carbonate, particularly in the form of calcium carbonate crystals, preferably has a positively charged surface. A cleaning effect is preferably achieved by adsorbing precipitated colloids and/or non-precipitable non-sugar substances present in the alkaline raw sugar juice onto the positively charged surface of the precipitated calcium carbonate. The precipitated calcium carbonate preferably acts as a separation aid. In particular, the precipitated calcium carbonate functions as a separation aid, since the precipitated calcium carbonate adsorbs substances that cannot be separated by, for example, filtration, for example suspended solids and/or non-precipitable non-sugar substances, and can thus be separated, in particular filtered off, together with the precipitated calcium carbonate. Through the reaction of the CO ₂ from the CO ₂ -enriched carbonation gas with the calcium hydroxide present in the alkaline carbonation educt, the CO ₂ content in the CO ₂ -enriched carbonation gas is reduced and a CO ₂ -depleted exhaust gas is obtained and discharged. The CO ₂ -depleted exhaust gas discharged from the respective carbonation step has a lower CO ₂ content than the CO ₂ -enriched carbonation gas introduced into the respective carbonation step, in particular min at least one by the CO ₂ content consumed in the reaction of CO ₂ with calcium hydroxide to form calcium carbonate in the alkaline carbonation educt. The alkaline carbonation intermediate product obtained after the first carbonation step b1) has a smaller amount of substances to be precipitated, in particular calcium hydroxide, than the alkaline carbonation starting material used in the first carbonation step b1). The alkaline carbonation intermediate product obtained after the first carbonation step b1) corresponds to the carbonation starting material of the at least one further carbonation step b2). According to the invention, a carbonation product is obtained after the last of the at least one further carbonation step b2), in particular after the second carbonation step. The carbonation product obtained after the last carbonation step, in particular second carbonation step, has a smaller amount of substances to be precipitated, in particular calcium hydroxide, in particular no substances to be precipitated, than the alkaline carbonation intermediate product of the first carbonation step b1) used in the last carbonation step, in particular second carbonation step b2). is called the carbonation educt of the last, in particular second, carbonation step b2).

According to the invention, in a method step c) according to the invention, at least a portion of the CO ₂ -depleted exhaust gas discharged from the at least one further carbonation step, in particular the second carbonation step, is converted into the alkaline carbonation educt, preferably into a raw sugar juice or a raw sugar solution, before or during the first carbonation step, in particular before the first carbonation step.

Very particularly preferably, in a further embodiment according to the invention, in process step c), at least a portion of the exhaust gas from a further carbonation step carried out after the first carbonation step, in particular a second carbonation step, is introduced into the alkaline carbonation educt of a carbonation step carried out before the first carbonation step, in particular a pre-carbonatation step.

According to the invention, in process step c), at least a portion of the exhaust gas from a further carbonation step carried out after the first carbonation step, in particular a second carbonation step, is introduced into the alkaline carbonation educt of the first carbonation step. In this embodiment, two streams of carbonation gases are introduced into the first carbonation step, namely a CO ₂ -enriched carbonation gas and a CO ₂ -depleted carbonation gas, i.e. the CO ₂ -depleted exhaust gas, from the second or at least one further carbonation step.

According to the invention, at least a portion of the exhaust gas from a further carbonation step carried out after the first carbonation step, in particular a second carbonation step, is preferably transferred into the alkaline carbonation educt of the first carbonation step and at least a further proportion of the exhaust gas from a further carbonation step carried out after the first carbonation step, in particular a second carbonation step, into that alkaline carbonation educt of a carbonation step carried out before the first carbonation step, in particular precarbonatation step b0), is initiated.

Preferably, by introducing in process step c) according to the invention the at least a portion of the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, into the alkaline carbonation educt of the first carbonation step or a carbonation step carried out before the first carbonation step, in particular the precarbonatation step, at least a portion of the unconsumed CO ₂ content in the exhaust gas of the at least one further carbonation step, in particular second carbonation step, is used to convert at least part of the calcium hydroxide present in the alkaline carbonation educt of the first or a carbonation step carried out before the first carbonation step, in particular precarbonatation step, to calcium carbonate. Preferably, the CO ₂ total gas utilization rate of the carbonation according to process step b) is advantageously increased by process step c) according to the invention, in particular compared to a comparable process (hereinafter also referred to as a comparative example).

Preferably, the additional use of at least a portion of the CO ₂ in the exhaust gas of the at least one further carbonation step, in particular second carbonation step, by introducing at least a portion of the exhaust gas into the alkaline carbonation educt of the first or a carbonation step carried out before the first carbonation step, in particular pre-carbonatation step, according to Method step c) according to the invention leads to an improvement in the CO ₂ total gas utilization rate of the carbonation according to method step b) of the present invention and to a reduction tion of the CO ₂ emission of the carbonation according to process step b) of the present invention in comparison to comparable processes. Preferably, method step c) according to the invention advantageously leads to a reduction in the CO ₂ emission of the carbonation according to method step b), since at least a portion of the unused CO ₂ of the CO ₂ -enriched carbonation gas of the at least one further carbonation step, which is discharged as CO ₂ -depleted exhaust gas, in particular second carbonation step, by the process step c) according to the invention, the carbonation according to process step b) of the present invention is recycled, in particular reacts with calcium hydroxide to form calcium carbonate, and is therefore not emitted into the environment, in particular as in comparable processes.

The present invention therefore relates in particular to a method for increasing the CO ₂ total gas utilization ratio in a method comprising method steps a), b) and c), in particular comprising method step b0).

The present invention therefore also relates in particular to a process for reducing CO ₂ emissions in a process for producing a carbonation product from a carbonation educt, comprising process steps a), b) and c), in particular b0).

In a preferred embodiment of the present invention, a precarbonatation step b0) is carried out before the first carbonation step b1).

In a preferred embodiment of the present invention, a second carbonation step b2) is carried out after the first carbonation step b1).

In a preferred embodiment of the present invention, at least one further carbonation step is carried out after the second carbonation step b2).

In a preferred embodiment of the present invention, a total of at least 2, in particular 2, in particular at least 3, in particular 3, in particular 4, in particular 5, in particular 6, carbonation steps are carried out in process step b).

In a preferred embodiment of the present invention, a precarbonatation step b0) is carried out before the first carbonation step b1) and a second carbonation step b2) is carried out after the first carbonation step b1).

In a preferred embodiment of the present invention, the carbonation educt is a raw sugar juice and the carbonation product is a thin juice.

In a preferred embodiment of the present invention, the carbonation educt is a raw sugar solution and the carbonation product is a purified raw sugar solution.

In a preferred embodiment of the present invention, the carbonation educt is a raw sugar juice and the carbonation product is a thin juice or the carbonation educt is a raw sugar solution and the carbonation product is a purified raw sugar solution.

In a preferred embodiment of the present invention, in process step b) after each carbonation step, a precipitated solid, in particular comprising calcium carbonate, is obtained.

In a preferred embodiment of the present invention, the precipitated solid obtained after a carbonation step comprises, in particular consists of, calcium carbonate and organic components, in particular colloid substances, in particular pectin, proteins, cellulose and hemicellulose.

In a preferred embodiment of the present invention, in process step b), after a carbonation step, the precipitated solid, in particular comprising calcium carbonate, is separated from the alkaline carbonation intermediate product, in particular raw sugar juice, or from the carbonation product, in particular thin juice.

In a preferred embodiment of the present invention, in process step b) after the first carbonation step b1), the precipitated solid, in particular comprising calcium carbonate, separated from the alkaline carbonation intermediate product, in particular raw sugar juice, by filtration or decantation.

In a preferred embodiment of the present invention, the solid separated after the first carbonation step b1) from the alkaline carbonation intermediate, in particular raw sugar juice, comprises calcium carbonate, in particular 50 to 80% by weight, in particular 55 to 75% by weight, in particular 60 to 70% by weight .-%, calcium carbonate and organic components, in particular 20 to 50% by weight, in particular 25 to 45% by weight, in particular 30 to 40% by weight (in each case based on the dry substance of the separated solid).

In a preferred embodiment of the present invention, the solid separated after the second carbonation step b2) from the alkaline carbonation intermediate or the carbonation product comprises calcium carbonate, in particular 90.0 to 99.9% by weight, in particular 95.0 to 99.9% by weight. -%, in particular 98.0 to 99.9% by weight, calcium carbonate and organic components, in particular 0.1 to 10.0% by weight, in particular 0.1 to 5.0% by weight, in particular 0, 1 to 2% by weight (in each case based on the dry matter of the separated solid), in particular consists of these.

In a preferred embodiment of the present invention, the solid separated after the precarbonatation step b0) from the alkaline carbonation intermediate, in particular raw sugar juice, comprises calcium carbonate, in particular 50 to 80% by weight, in particular 55 to 75% by weight, in particular 60 to 70% by weight. -%, calcium carbonate and organic components, in particular 20 to 50% by weight, in particular 25 to 45% by weight, in particular 30 to 40% by weight (in each case based on the dry matter of the separated solid).

In a preferred embodiment of the present invention, in process step b) after the second carbonation step b2), the precipitated solid, in particular comprising calcium carbonate, is separated from the alkaline carbonation intermediate or the carbonation product by filtration.

In a preferred embodiment of the present invention, in process step b) after the first carbonation step b1), the precipitated solid, in particular comprising calcium carbonate, is filtered from the alkaline carbonation intermediate product, in particular raw sugar juice, and after the second carbonation step b2), the precipitated solid, in particular comprising Calcium carbonate, separated by filtration from the alkaline carbonation intermediate product, in particular sugar raw juice, or the carbonation product, in particular thin juice.

In a preferred embodiment of the present invention, in process step b) after the first carbonation step b1), the precipitated solid, in particular comprising calcium carbonate, is decanted from the alkaline carbonation intermediate product, in particular raw sugar juice, and after the second carbonation step b2), the precipitated solid, in particular comprising Calcium carbonate, separated by filtration from the alkaline carbonation intermediate product, in particular sugar raw juice, or carbonation product, in particular thin juice.

In a preferred embodiment of the present invention, in process step b) after the first carbonation step b1), the precipitated solid, in particular comprising calcium carbonate, is not separated from the alkaline carbonation intermediate and at least one further carbonation step b2) is carried out, the precipitated solid of all carbonation steps carried out after The last carbonation step is separated from the carbonation product, in particular from the purified raw sugar solution, in particular by filtration.

In a preferred embodiment of the present invention, in process step b) after the first carbonation step b1), the precipitated solid, in particular comprising calcium carbonate, is not separated from the alkaline carbonation intermediate, in particular from the raw sugar solution, and a second carbonation step b2) is carried out, the precipitated solid , in particular comprising calcium carbonate, of the first carbonation step b1) and the precipitated solid, in particular comprising calcium carbonate, of the second carbonation step b2) are separated from the carbonation product, in particular from the purified raw sugar solution, after the second carbonation step, in particular by filtration.

In a preferred embodiment of the present invention, the at least a portion of the exhaust gas from the at least one further carbonation step from process step b) is introduced into the alkaline carbonation educt of the first carbonation step or the precarbonatation step according to process step c).

In a preferred embodiment of the present invention, the at least a portion of the exhaust gas from the second carbonation step is introduced into the alkaline carbonation educt from the first carbonation step according to process step c).

In a particularly preferred embodiment of the present invention, the at least a portion of the exhaust gas from the second carbonation step according to process step c) is introduced into the alkaline carbonation educt of the precarbonatation step.

By introducing the at least a portion of the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, into the alkaline carbonation educt of the precarbonatation step, the CO ₂ total gas utilization rate of the carbonation step is advantageously increased, in particular the CO ₂ total gas utilization rate of the carbonation process of the invention is higher than the overall gas utilization rate of comparable processes. Preferably and advantageously, the CO ₂ total gas utilization rate of the carbonation of the preferred process according to the invention, in which the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, is introduced into the alkaline carbonation educt of a precarbonatation step according to process step c) according to the invention is higher than in a carbonation in which the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, is introduced into the alkaline carbonation educt of the first carbonation step, in particular since the gas utilization rate of a first carbonation step is already at least 80%. This is because the calcium hydroxide contained in the alkaline carbonation educt of the first carbonation step is preferably reacted largely with the CO ₂ of the CO ₂ -enriched carbonation gas used for the first carbonation step, in particular fresh, for example freshly obtained from a lime kiln or present as boiler house gas, to form calcium carbonate , which is why by introducing according to the invention, in particular in addition to the fresh CO ₂ -enriched carbonation gas, the at least a portion of the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, into the alkaline carbonation educt of the first carbonation step, the CO ₂ total gas utilization rate of the carbonation according to the method step b) the present invention cannot be increased to the extent that by introducing the at least a portion of the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, into the alkaline carbonation educt of the precarbonatation step, as the only one, i.e. into the not fresh one CO ₂ -enriched carbonation gas is introduced. The calcium hydroxide of the precarbonatation step present in the alkaline carbonation educt is characterized by the fact that it does not come into contact with CO ₂ of a fresh CO ₂ -enriched carbonation gas, and in particular is not thereby converted into calcium carbonate. Preferably, through the precarbonatation step, at least a portion of an already used carbonation gas from the at least one further carbonation step b2), in particular second carbonation step, is converted into a fresh alkaline carbonation educt, i.e. an alkaline carbonation educt, as a single, sole CO ₂ -enriched carbonation gas no fresh CO ₂ -enriched carbonation gas was introduced, and the calcium hydroxide present therein was converted into calcium carbonate. Fresh CO ₂ -enriched carbonation gas, which is not a CO ₂ -enriched carbonation gas, is preferably added to the alkaline carbonation intermediate product or alkaline carbonation educt obtained from the precarbonatation step in a first carbonation step, which was previously obtained as CO ₂ -depleted exhaust gas from at least one further carbonation step according to method step b2). was initiated. In particular, the CO ₂ total gas utilization rate of the carbonation according to process step b) of the present invention is thereby increased in a particularly advantageous manner, especially in comparison to comparable processes.

In a preferred embodiment of the present invention, after the precarbonatation step b0), an alkaline carbonation intermediate is obtained which has fewer substances to be precipitated, in particular comprising calcium hydroxide, than the alkaline carbonation educt before the precarbonatation step.

In a preferred embodiment of the present invention, after the first carbonation step b1), an alkaline carbonation intermediate product is obtained which contains fewer substances to be precipitated, in particular comprising calcium hydroxide, as the alkaline carbonation educt before the first carbonation step.

In a preferred embodiment of the present invention, a carbonation product is obtained after the last carbonation step.

In a preferred embodiment of the present invention, a carbonation product is obtained after the second carbonation step b2).

1. a) Alkalisierung von einem Carbonatationsedukt unter Erhalt eines alkalischen Carbonatationsedukts und
2. b) Carbonatation des alkalischen Carbonatationsedukts umfassend, insbesondere bestehend aus, einen ersten und einen zweiten Carbonatationsschritt b1) und b2) unter Erhalt eines Carbonatationsprodukts, im Rahmen derer jeweils ein CO₂-angereichertes Carbonatationsgas in das alkalische Carbonatationsedukt eingeleitet und ein CO₂-abgereichertes Abgas ausgeleitet wird, gekennzeichnet durch
3. c) Einleiten mindestens eines Anteils des Abgases des zweiten Carbonatationsschritts in das alkalische Carbonatationsedukt während dem ersten Carbonatationsschritt.

In a preferred embodiment of the present invention, the invention relates to a process for producing a carbonation product from a carbonation educt, comprising the process steps:

1. a) Alkalization of a carbonation educt to obtain an alkaline carbonation educt and
2. b) carbonation of the alkaline carbonation educt comprising, in particular consisting of, a first and a second carbonation step b1) and b2) to obtain a carbonation product, in the course of which a CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt and a CO ₂ -depleted exhaust gas is discharged, characterized by
3. c) introducing at least a portion of the exhaust gas from the second carbonation step into the alkaline carbonation educt during the first carbonation step.

In this embodiment, two different carbonation gases are introduced into the first carbonation step, namely a CO ₂ -enriched carbonation gas and a CO ₂ -depleted carbonation gas, in particular exhaust gas, from the second or further carbonation step.

1. a) Alkalisierung von einem Carbonatationsedukt unter Erhalt eines alkalischen Carbonatationsedukts und
2. b) Carbonatation des alkalischen Carbonatationsedukts umfassend, insbesondere bestehend aus, einen Vorcarbonatationsschritt b0), einen ersten Carbonatationsschritt b1) und einen zweiten Carbonatationsschritt b2) unter Erhalt eines Carbonatationsprodukts, im Rahmen derer jeweils ein CO₂-angereichertes Carbonatationsgas in das alkalische Carbonatationsedukt eingeleitet und ein CO₂-abgereichertes Abgas ausgeleitet wird, gekennzeichnet durch
3. c) Einleiten mindestens eines Anteils des Abgases des zweiten Carbonatationsschritts in das alkalische Carbonatationsedukt vor dem ersten Carbonatationsschritt, insbesondere in das alkalische Carbonatationsedukt während des Vorcarbonatationsschritts, insbesondere als einziges, alleiniges CO₂-angereichertes Carbonatationsgas.

In a preferred embodiment of the present invention, the invention relates to a process for producing a carbonation product from a carbonation educt, comprising the process steps:

1. a) Alkalization of a carbonation educt to obtain an alkaline carbonation educt and
2. b) Carbonation of the alkaline carbonation educt comprising, in particular consisting of, a precarbonatation step b0), a first carbonation step b1) and a second carbonation step b2) to obtain a carbonation product, in the context of which a CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt and a CO ₂ -depleted exhaust gas is discharged, characterized by
3. c) introducing at least a portion of the exhaust gas from the second carbonation step into the alkaline carbonation educt before the first carbonation step, in particular into the alkaline carbonation educt during the pre-carbonatation step, in particular as a single, sole CO ₂ -enriched carbonation gas.

In a preferred embodiment of the present invention, the method is carried out in a device for producing a carbonation product from a carbonation educt comprising at least a first carbonation container and at least one further carbonation container.

In a preferred embodiment of the present invention, the method is carried out in a beet sugar or sugar cane sugar processing device for producing thin juice from sugar raw juice, comprising at least a first carbonation container and at least one further carbonation container.

In a preferred embodiment of the present invention, the method is carried out in a sugar refining device for producing a purified raw sugar solution from a raw sugar solution comprising at least a first carbonation container and at least one further carbonation container.

In a preferred embodiment of the method of the present invention, the device has at least one pre-carbonatation container upstream of the first carbonation container.

In a preferred embodiment of the method of the present invention, the device has a second carbonation container connected downstream of the first carbonation container.

In a preferred embodiment of the method of the present invention, the device has a pre-carbonatation container connected upstream of the first carbonation container and a second carbonation container connected downstream of the first carbonation container.

In a preferred embodiment of the process of the present invention, each carbonation step is carried out in its own carbonation container.

In a preferred embodiment of the process of the present invention, all carbonation steps are carried out in a carbonation vessel.

In a preferred embodiment of the method of the present invention, the first carbonation step is carried out in a first carbonation container and the second carbonation step is carried out in a second carbonation container.

In a preferred embodiment of the method of the present invention, the first carbonation step is carried out in a first carbonation container, the second carbonation step is carried out in a second carbonation container and the pre-carbonatation step is carried out in a pre-carbonatation container.

In a preferred embodiment of the process of the present invention, the first carbonation step, the second carbonation step and the precarbonatation step are each carried out in a carbonation container.

In a preferred embodiment of the method of the present invention, the device has at least one line from the at least one further carbonation container, in particular second carbonation container, to an upstream carbonation container, in particular first carbonation container or pre-carbonatation container, in order to transport at least part of the exhaust gas from the at least one further carbonation step , in particular second carbonation step, into the alkaline carbonation educt before or during the first carbonation step.

In a preferred embodiment of the method of the present invention, the device has at least one line from the second carbonation container to the first carbonation container in order to convert at least part of the exhaust gas from the second carbonation step into the alkaline carbonation educt during the first carbonation step, in particular in addition to in a lime kiln obtained or at least partially present in a boiler house gas as CO ₂ -enriched carbonation gas.

In a preferred embodiment of the method of the present invention, the device has at least one line from the second carbonation container to the at least one precarbonatation container in order to convert at least part of the exhaust gas from the second carbonation step into the alkaline carbonation educt before the first carbonation step, in particular the precarbonatation step, in particular as to initiate a single, exclusive CO ₂ -enriched carbonation gas.

In a preferred embodiment of the present invention, the exhaust gas from the first carbonation step has a CO ₂ content of 1 to 10 vol.%, in particular 1 to 8 vol.%, in particular 2 to 6 vol.%, in particular 3 to 4 vol .-%, (based on the total volume of exhaust gas in the first carbonation step).

In a preferred embodiment of the present invention, the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, has a CO ₂ content of 1 to 40% by volume, in particular 5 to 35% by volume, in particular 10 to 30% by volume. %, in particular 15 to 27% by volume, in particular 26.3% by volume, in particular 21.4% by volume, in particular 17.9% by volume, in particular 15.7% by volume, (based on Total volume of exhaust gas at least one further carbonation step).

In a preferred embodiment of the present invention, the exhaust gas from the precarbonatation step has a CO ₂ content of 1 to 10% by volume, in particular 2 to 8% by volume, in particular 3 to 6% by volume (based on the total volume of exhaust gas from the precarbonatation step ) on.

In a preferred embodiment of the present invention, the exhaust gas from the at least one further carbonation step, in particular the second carbonation step, is mixed with a CO ₂ -enriched carbonation gas after process step b) and before process step c).

In a preferred embodiment of the present invention, the CO ₂ -enriched carbonation gas of a beet sugar or sugar cane sugar processing device is obtained by a coke or gas-fired lime kiln.

In a preferred embodiment of the present invention, the CO ₂ -enriched carbonation gas of a sugar refining device is at least a portion of a boiler house gas.

In a preferred embodiment of the present invention, the CO ₂ -enriched carbonation gas is obtained by a coke- or gas-operated lime kiln or is at least a portion of a boiler house gas.

In a preferred embodiment of the present invention, the CO ₂ -enriched carbonation gas obtained by a coke- or gas-operated lime kiln has a CO ₂ content of 1 to 99% by volume, in particular 10 to 70% by volume, in particular 20 up to 50% by volume, in particular 25 to 45% by volume, in particular 26 to 42% by volume, in particular 41.5% by volume, in particular 35.0% by volume, in particular 30.1% by volume , in particular 26.0% by volume (based on the total volume of CO ₂ -enriched gas).

In a preferred embodiment of the present invention, the CO ₂ -enriched carbonation gas of at least a portion of the boiler house gas has a CO ₂ content of 1 to 99 vol.%, in particular 10 to 70 vol.%, in particular 20 to 50 vol.% , in particular 25 to 45% by volume, in particular 26 to 42% by volume, in particular 41.5% by volume, in particular 35.0% by volume, in particular 30.1% by volume, in particular 26.0 % by volume, in particular 20.0% by volume, in particular 15.0% by volume, in particular 10.0% by volume (based on the total volume of CO ₂ -enriched gas).

In a preferred embodiment of the present invention, the CO ₂ -enriched carbonation gas obtained by a coke- or gas-operated lime kiln or the CO ₂ -enriched carbonation gas of at least a portion of the boiler house gas is mixed with air, in particular ambient air, in particular around the CO ₂ content of the CO ₂ enriched carbonation gas.

In a preferred embodiment of the present invention, the retention time of the CO ₂ -enriched carbonation gas in the respective carbonation container, in particular pre-carbonatation container, first carbonation container and/or at least one further carbonation container, in particular second carbonation container, is 1.0 to 15.0 minutes, in particular 2.0 to 12.0 minutes, in particular 2.5 to 10.0 minutes, in particular 2.5 minutes, in particular 4 minutes, in particular 6 minutes, in particular 8 minutes, in particular 10 minutes.

In a preferred embodiment of the present invention, the sugar raw juice is obtained from sugar beets or sugar cane.

In a preferred embodiment of the present invention, a raw sugar solution is obtained by dissolving raw sugar in water.

In a preferred embodiment of the present invention, a raw sugar solution has 10 to 95% by weight, in particular 20 to 90% by weight, in particular 30 to 85% by weight, in particular 40 to 80% by weight, in particular 50 to 70% by weight .-%, in particular 55 to 65% by weight, in particular 60% by weight, raw sugar and 5 to 90% by weight, in particular 10 to 80% by weight, in particular 15 to 70% by weight, in particular 20 up to 60% by weight, in particular 30 to 50% by weight, in particular 35 to 45% by weight, in particular 40% by weight, of water (in each case based on the total weight of raw sugar solution).

In a preferred embodiment of the present invention, the CO ₂ gas utilization rate of the first carbonation step is at least 80%, in particular at least 85%, in particular at least 90%, in particular 90 to 95%, in particular 92%, in particular 95%.

In a preferred embodiment of the present invention, the retention time of the CO ₂ -enriched carbonation gas in the first carbonation container is 1.0 to 15.0 minutes, in particular 2.0 to 12.0 minutes, in particular 2.5 to 10.0 minutes, in particular 2.5 minutes, in particular 4 minutes, in particular 6 minutes, in particular 8 minutes, in particular 10 minutes and the gas utilization rate of the first carbonation step is at least 80% , in particular at least 85%, in particular at least 90%, in particular 90 to 95%, in particular 92%, in particular 95%.

In a preferred embodiment of the present invention, the CO ₂ gas utilization rate of the at least one further carbonation step, in particular the second carbonation step, is at least 20%, in particular at least 30%, in particular at least 40%, in particular at least 45%, in particular 47 to 60%, in particular 47 %, especially 49%, especially 50%.

In a preferred embodiment of the present invention, the retention time of the CO ₂ -enriched carbonation gas in at least one further carbonation container, in particular the second carbonation container, is 1.0 to 15.0 minutes, in particular 2.0 to 12.0 minutes, in particular 2.5 to 10.0 minutes, in particular 2.5 minutes, in particular 4 minutes, in particular 6 minutes, in particular 8 minutes, in particular 10 minutes and the degree of gas utilization of the at least one further carbonation step, in particular second carbonation step, at least 20%, in particular at least 30%, in particular at least 40%, in particular at least 45%, in particular 47 to 60%, in particular 47%, in particular 49%, in particular 50%.

In a preferred embodiment of the present invention, the CO ₂ gas utilization rate of the precarbonatation step is at least 70%, in particular at least 75%, in particular at least 80%, in particular more than 80%, in particular 80 to 88%, in particular 80%, in particular 81%, in particular 82%, especially 83%, especially 84%, especially 85%, especially 86%, especially 87%, especially 88%.

In a preferred embodiment of the present invention, the retention time of the CO ₂ -enriched carbonation gas in the precarbonatation container is 1.0 to 15.0 minutes, in particular 2.0 to 12.0 minutes, in particular 2.5 to 10.0 minutes, in particular 2 .5 minutes, in particular 4 minutes, in particular 6 minutes, in particular 8 minutes, in particular 10 minutes and the degree of gas utilization of the precarbonatation step is at least 70%, in particular at least 75%, in particular at least 80%, in particular more than 80%, in particular 80 to 88%, in particular 80%, in particular 81%, in particular 82%, in particular 83% in particular 84%, in particular 85%, in particular 86%, in particular 87%, in particular 88%.

In a preferred embodiment of the present invention, the CO ₂ total gas utilization rate of the carbonation according to process step b) is at least 50%, in particular at least 55%, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90%, in particular 50 to 99%, in particular 60 to 98%, in particular 70 to 97%, in particular 80 to 96%, in particular 90 to 95%, in particular 92%, in particular 95%.

In a preferred embodiment of the present invention, the CO ₂ total gas utilization rate of the carbonation according to process step b) is at least 3%, in particular at least 5%, in particular at least 7%, in particular 7%, in particular, compared to a comparable process without carrying out process step c) according to the invention 8%, especially 9%, improved.

In a preferred embodiment of the present invention, the CO ₂ emission of the carbonation according to process step b) is at least 20%, in particular at least 30%, in particular at least 40%, in particular 43%, in particular compared to a comparable process without carrying out process step c) according to the invention 44%, especially 46%, especially 54%, especially 56%, especially 57%, reduced.

The present invention also relates to a device for producing a carbonation product from a carbonation reactant, particularly suitable and designed for carrying out a method according to the invention, comprising at least a first carbonation container, at least one further carbonation container and at least one line from the at least one further carbonation container into an upstream carbonation container , which is suitable for introducing at least part of an exhaust gas from the at least one further carbonation container into an alkaline carbonation educt, in the present case in an upstream carbonation container.

In a preferred embodiment of the present invention, the device according to the invention comprises at least one alkalinization container, in particular at least one liming container, in particular a preliming container and a main liming container.

In a preferred embodiment of the device according to the invention, the first carbonation container is preceded by a precarbonatation container.

In a preferred embodiment of the device according to the invention, a second carbonation container is connected downstream of the first carbonation container.

In a preferred embodiment of the device according to the invention, a pre-carbonatation container is connected upstream of the first carbonation container and a second carbonation container is connected downstream.

In a preferred embodiment of the device according to the invention, the upstream carbonation container is the first carbonation container or the pre-carbonatation container.

In a preferred embodiment of the present invention, the device according to the invention comprises a total of at least 2, in particular 2, in particular at least 3, in particular 3, in particular 4, in particular 5, in particular 6, carbonation containers.

In a preferred embodiment of the present invention, the device according to the invention has at least one line from the second carbonation container into the first carbonation container, which is suitable for introducing at least part of an exhaust gas from the second carbonation container into an alkaline carbonation educt present in the first carbonation container.

In a preferred embodiment of the present invention, the device according to the invention has at least one line from the second carbonation container into the at least one precarbonatation container, which is suitable for transferring at least part of an exhaust gas from the second carbonation container into an alkaline carbonation educt present in the precarbonatation container, in particular as the only one , to introduce sole CO ₂ -enriched carbonation gas.

In a preferred embodiment of the present invention, the device for producing a carbonation product from a carbonation educt, particularly suitable and designed for carrying out a method according to the invention, comprises a first carbonation container, a second carbonation container connected downstream of the first carbonation container and a line from the second carbonation container into the first carbonation container upstream of the second carbonation container, which is suitable for converting at least part of an exhaust gas from the second carbonation container into an alkaline carbonation educt in the present case in the first carbonation container upstream of the second carbonation container, in particular in addition to CO obtained in a lime kiln or present at least in part in a boiler house gas ₂ enriched carbonation gas.

In a preferred embodiment of the present invention, the device for producing a carbonation product from a carbonation reactant, particularly suitable and designed for carrying out a method according to the invention, comprises a first carbonation container, a second carbonation container downstream of the first carbonation container, a pre-carbonatation container upstream of the first carbonation container and a line from the second carbonation container into the pre-carbonatation container upstream of the first carbonation container, which is suitable for introducing at least part of an exhaust gas from the second carbonation container into an alkaline carbonation educt, in the present case into the pre-carbonatation container upstream of the first carbonation container, in particular as a single, sole CO ₂ -enriched carbonation gas .

In a preferred embodiment of the present invention, the device according to the invention is a beet sugar or sugar cane sugar processing device for producing thin juice from sugar raw juice.

In a preferred embodiment of the present invention, the device according to the invention is a sugar refining device for producing a purified raw sugar solution from a raw sugar solution.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, each carbonation container is followed by a separation device, in particular a filtering device.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, each separation device, in particular filtering device, is followed by a storage container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, each carbonation container is preceded by a storage container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, the second carbonation container is preceded by a storage container.

In a preferred embodiment of the device according to the invention, in particular a beet sugar or sugar cane sugar processing device, a first separation device, in particular a filtering device, is connected downstream of the first carbonation container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, a first separation device, in particular a filtering device, is connected downstream of the first carbonation container and a storage container is connected downstream of the first separation device.

In a preferred embodiment of the device according to the invention, a second separation device, in particular a filtering device, is connected downstream of the second carbonation container.

In a preferred embodiment of the device according to the invention, in particular a beet sugar or sugar cane sugar processing device, a separation device, in particular a filtering device, is connected downstream of the precarbonatation container.

In a preferred embodiment of the device according to the invention, in particular a sugar refining device, there is no separating device, in particular a filtering device, connected downstream of the precarbonatation container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, at least one precarbonatation container is connected upstream of the first carbonation container and a separation device, in particular a filtering device, is interposed between the first carbonation container and the precarbonatation container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, the first carbonation container is preceded by a precarbonatation container, a separation device, in particular a filtering device, is interposed between the first carbonation container and the precarbonatation container, a second carbonation container is connected downstream of the first carbonation container and between the first A first separation device is interposed between the carbonation container and the second carbonation container, in particular a storage container is interposed between the first separation device and the second carbonation container.

In a preferred embodiment of the device according to the invention, the first carbonation container is preceded by a pre-carbonatation container, no separating device is interposed between the first carbonation container and the pre-carbonatation container, a second carbonation container is connected downstream of the first carbonation container and a first separating device is interposed between the first carbonation container and the second carbonation container, in particular a storage container is interposed between the first separation device and the second carbonation container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, the first carbonation container is a pre-carbo ation container, a separation device, in particular a filtering device, is interposed between the first carbonation container and the pre-carbonatation container, a second carbonation container is connected downstream of the first carbonation container, a first separation device, in particular a filtering device, is interposed between the first carbonation container and the second carbonation container, and a second one after the second carbonation container Separation device, in particular filter device, downstream.

In a preferred embodiment of the device according to the invention, the first carbonation container is preceded by a pre-carbonatation container, no separating device is interposed between the first carbonation container and the pre-carbonatation container, a second carbonation container is connected downstream of the first carbonation container, and a first separation device, in particular a filtering device, is connected between the first carbonation container and the second carbonation container , interposed and downstream of the second carbonation container a second separation device, in particular a filtering device.

In a preferred embodiment of the device according to the invention, in particular a sugar refining device, a pre-carbonatation container is connected upstream of the first carbonation container, no separating device is connected between the first carbonation container and the pre-carbonatation container, a second carbonation container is connected downstream of the first carbonation container, and no first carbonation container is connected between the first carbonation container and the second carbonation container Separating device is interposed and a second separating device, in particular a filtering device, is connected downstream of the second carbonation container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, a second carbonation container is connected downstream of the first carbonation container and a first separation device, in particular a filtering device, is interposed between the first carbonation container and the second carbonation container.

In a preferred embodiment of the device according to the invention, in particular a sugar refining device, a second carbonation container is connected downstream of the first carbonation container, no first separation device is connected between the first carbonation container and the second carbonation container, and a second separation device, in particular a filtering device, is connected downstream of the second carbonation container.

In a preferred embodiment of the device according to the invention, in particular beet sugar or sugar cane sugar processing device, a second carbonation container is connected downstream of the first carbonation container, a first separation device, in particular a filtering device, is interposed between the first carbonation container and the second carbonation container, and after the second carbonation container a second separation device, in particular a filtering device , connected downstream.

In a preferred embodiment, the device according to the invention, in particular a beet sugar or sugar cane sugar processing device, comprises a lime kiln powered by coke or gas.

In a preferred embodiment, the device according to the invention, in particular a sugar refining device, comprises a boiler house, in particular a gas-operated boiler house.

In the context of the present invention, “carbonatation educt” is understood to mean the educt intended for carrying out a carbonation. The carbonation educt is preferably a raw sugar juice. The carbonation educt is preferably a raw sugar solution. A carbonation educt preferably has a larger amount of substances to be precipitated and/or suspended matter than the carbonation product obtained from the carbonation educt by carrying out a carbonation.

In the context of the present invention, “carbonatation product” is understood to mean the product obtained by carrying out a carbonation. The carbonation product is preferably a thin juice. The carbonation product is preferably a purified raw sugar solution. Due to a carbonation carried out, a carbonation product preferably has a smaller amount of substances to be precipitated, in particular comprising calcium hydroxide, and/or suspended matter than the carbonation educt. Preferably, the carbonation product does not have any to be precipitated due to carbonation being carried out Substances, in particular no calcium hydroxide, and/or suspended matter. The carbonation product is preferably obtained after the last carbonation step, in particular the second carbonation step. After the last carbonation step, solid material that has not been separated off by the last carbonation step, in particular calcium carbonate, is preferably present in the carbonation product.

In the context of the present invention, “raw sugar solution” is understood to mean raw sugar dissolved in water. A raw sugar solution preferably has a larger amount of substances to be precipitated and/or suspended matter than the purified raw sugar solution obtained from the raw sugar solution by carrying out carbonation.

In the context of the present invention, “raw sugar” is understood to mean unrefined sugar. The raw sugar is preferably processed into refined sugar in a sugar refinery. Raw sugar preferably has a brownish color.

In the context of the present invention, “refined sugar” is understood to mean sugar obtained from raw sugar by refining. Refined sugar is preferably white in color.

In the context of the present invention, “purified raw sugar solution” is understood to mean the raw sugar solution obtained from a raw sugar solution after carbonation has been carried out. Preferably, a purified raw sugar solution, due to carbonation carried out, has a smaller amount of substances to be precipitated, in particular comprising calcium hydroxide, and/or suspended matter than the raw sugar solution used in the carbonation, in particular alkaline raw sugar solution. Preferably, the purified raw sugar solution does not contain any substances to be precipitated due to carbonation being carried out, in particular no calcium hydroxide, and/or suspended matter. The purified raw sugar solution is preferably obtained after carrying out the last carbonation step. After the last carbonation step, solid material that has not been separated off by the last carbonation step, in particular calcium carbonate, is preferably present in the purified raw sugar solution.

In the context of the present invention, “sugar raw juice” is understood to mean the juice obtained after extraction from a solid sugar source, in particular sugar beets, in particular sugar beet pulp, or sugar cane. The sugar raw juice is preferably extracted from sugar beets, in particular sugar beet pulp, or sugar cane with hot water, in particular 70 ° C, in an extraction tower. The sugar raw juice is preferably cloudy. After extraction, up to 99% by weight of the sugar from the sugar beet or sugar cane (based on the total weight of sugar in the sugar beet or sugar cane) is preferably present in the sugar raw juice. In addition to sugar, the raw sugar juice preferably includes other substances, in particular suspended solids and non-precipitable non-sugar substances.

In the context of the present invention, “suspended solids” are understood to mean solid substances, in particular mineral or organic solids, which do not dissolve in an ambient medium, in particular water, and are kept in suspension because of their small size and low weight.

In the context of the present invention, “non-precipitable non-sugar substances” is understood to mean non-sugar substances, i.e. substances that are not sugar, which cannot be precipitated by the liming carried out in sugar production or sugar refining, in particular preliminary and main liming.

In the context of the present invention, “liming” is understood to mean a process step before carbonation. Liming preferably includes, and in particular consists of, preliminary and/or main liming. A carbonation educt is preferably alkalized to an alkaline carbonation educt in a liming process. Liming is also preferably understood to mean alkalinization.

In the context of the present invention, “pre-liming” is understood to mean a process step in sugar production, in particular juice purification, or sugar refining, in which the pH of a carbonation educt, in particular raw sugar juice or raw sugar solution, is raised to pH 10.6 to 11 through the use of milk of lime .6 is increased. Pre-liming preferably precipitates colloids and insoluble salts from the carbonation educt.

In the context of the present invention, “main liming” is understood to mean a process step in sugar production, in particular juice purification, or sugar refining, in which the pH value of a carbonation educt obtained from preliming is further increased to pH 12 to 12.6 by using lime milk to obtain an alkaline carbonation educt. The main liming process preferably breaks down the invertase and acid amides present in the carbonation educt.

In the context of the present invention, “lime milk” is understood to mean a calcium hydroxide dispersion in water. Lime milk is preferably used in the preliminary and main liming of sugar production or sugar refining. Lime milk is preferably used to precipitate non-sugar substances and suspended solids. The non-sugar substances and suspended solids are preferably adsorbed by the solid calcium hydroxide present in the lime milk.

In the context of the present invention, “thin juice” is also understood to mean thin sugar juice. In the context of the present invention, “thin juice” is an intermediate product in sugar production, in particular obtained from sugar beets or sugar cane. Thin juice is preferably obtained from sugar raw juice by the process according to the invention. The thin juice preferably contains 10 to 20% raw sugar (based on the total thin juice composition). The thin juice is preferably clear and the color of the thin juice is light yellow.

In the context of the present invention, “sugar” is understood to mean a mono- or disaccharide, in particular glucose and sucrose, in particular sucrose.

In the context of the present invention, “alkalization” is understood to mean an increase in the pH of a carbonation educt. The alkalinization of the carbonation educt preferably increases the pH of the carbonation educt to pH 11 to 12. The alkalinization preferably includes, in particular consists of, preliming and/or main liming. During alkalinization, the pH value of the carbonation educt is preferably increased by using milk of lime. An alkaline carbonation educt is preferably obtained by alkalizing a carbonation educt. Alkaline raw sugar juice is preferably obtained by alkalizing raw sugar juice. An alkaline raw sugar solution is preferably obtained by alkalizing a raw sugar solution.

In the context of the present invention, “adsorption” is understood to mean the enrichment, in particular adhesion, of a substance, in particular a non-sugar substance and/or suspended matter, on the surface of a solid, in particular calcium hydroxide and/or calcium carbonate. The substances preferably interact with the surface of the solid through non-covalent interactions. According to the invention, adsorption is also understood to mean physisorption.

In the context of the present invention, “main liming alkalinity” is understood to mean the alkalinity of the alkaline carbonation educt obtained by a main liming. Main lime alkalinity is preferably understood to mean an alkalinity of 0.6 to 1.2 g CaO/100 mL.

In the context of the present invention, “alkaline carbonation educt” is understood to mean a carbonation educt obtained after alkalinization according to process step a) of the process according to the invention. Preliminary and/or main liming is preferably carried out to obtain an alkaline carbonation educt. An alkaline carbonation educt preferably contains calcium hydroxide. An alkaline carbonation educt is preferably an alkaline raw sugar juice. An alkaline carbonation reactant is preferably an alkaline raw sugar solution.

In the context of the present invention, “alkaline carbonation intermediate” is understood to mean an alkaline intermediate product obtained after carrying out a pre-carbonatation step, a first carbonation step or at least one further carbonation step which is not the last carbonation step. In connection with the present invention, the alkaline carbonation intermediate product obtained after the respective carbonation step carried out, in particular precarbonatation step, first carbonation step or at least one further carbonation step which is not the last carbonation step, is at the same time the alkaline carbonation educt used in the following carbonation step.

In the context of the present invention, “carbonatation” is understood to mean a purification of an alkaline carbonation educt to obtain a carbonation product, in particular by introducing CO ₂ and separating off a precipitated solid. Preferably, the carbonation of the present invention comprises at least two carbonation steps. Preferably, the carbonation of the present invention comprises a first carbonation step, a second Carbonation step and optionally a pre-carbonatation step. The carbonation of the present invention preferably comprises at least one separation step of a solid precipitated by a carbonation step from an alkaline carbonation intermediate to obtain an alkaline carbonation educt, in particular which has fewer substances to be precipitated than the alkaline carbonation educt before carrying out the carbonation step. The carbonation of the present invention preferably comprises a step of separating a solid precipitated by a carbonation step from a carbonation product to obtain the carbonation product separated from the solid formed by the carbonation step. Preference is given to “carbonatation” as process step b) of the present invention comprising introducing a CO ₂ -enriched carbonation gas into an alkaline carbonation educt at least twice, discharging a CO ₂ -depleted exhaust gas at least twice, separating a solid from a carbonation product to obtain the Carbonation product and optionally a separation of a solid from an alkaline carbonation intermediate.

In connection with the present invention, “carbonatation step” is understood to mean introducing a CO ₂ -enriched carbonation gas into an alkaline carbonation educt and removing a CO ₂ -depleted exhaust gas from the alkaline carbonation intermediate or carbonation product formed by the carbonation step. A carbonation step is preferably carried out in a carbonation container. Preferably, in a carbonation step, a solid is precipitated from the alkaline carbonation educt by introducing a CO ₂ -enriched carbonation gas into an alkaline carbonation educt. The solid precipitated from the alkaline carbonation educt preferably has calcium carbonate and optionally non-precipitable non-sugar substances and/or suspended solids. Preferably, in a carbonation step, the CO ₂ of the introduced CO ₂ -enriched carbonation gas reacts with the calcium hydroxide contained in the alkaline carbonation educt to form calcium carbonate, whereby a CO ₂ -depleted exhaust gas and an alkaline carbonation intermediate having a smaller amount of precipitated substances than before the carbonation step or a carbonation product is obtained . The CO ₂ -depleted exhaust gas obtained in the carbonation step is preferably discharged from the carbonation container.

In the context of the present invention, “CO ₂ -enriched carbonation gas” is understood to mean a gas containing CO ₂ produced for the carbonation. The CO ₂ -enriched carbonation gas is preferably generated by a lime kiln powered by coke or gas. The CO ₂ -enriched carbonation gas is preferably at least a portion of a boiler house gas. The CO ₂ -enriched carbonation gas can preferably be at least a portion of the exhaust gas discharged from the at least one further carbonation step, in particular the second carbonation step, and is introduced into the alkaline carbonation educt before or during the first carbonation step according to process step c) according to the invention. This CO ₂ -depleted exhaust gas or carbonation gas can therefore be understood as CO ₂ -enriched carbonation gas, since the CO ₂ content in the carbonation gas is reduced during the implementation of the first carbonation step or a carbonation step before the first carbonation step, in particular a precarbonatation step. The CO ₂ content of the CO ₂ -enriched carbonation gas can preferably be adjusted by adding air. The CO ₂ -enriched carbonation gas preferably has a CO ₂ content of at least 40.0% by volume, in particular 41.5% by volume, (based on the total volume of carbonation gas) without the addition of air. The CO ₂ -enriched carbonation gas is preferably introduced into an alkaline carbonation reactant present in a carbonation container during a carbonation step. The CO ₂ of the CO ₂ -enriched carbonation gas preferably reacts with the calcium hydroxide present in the alkaline carbonation educt to form calcium carbonate, whereby a CO ₂ -depleted exhaust gas is obtained. The CO ₂ -enriched carbonation gas preferably has a higher CO ₂ content than the CO ₂ -depleted exhaust gas (in each case based on the total volume of carbonation gas or exhaust gas).

In connection with the present invention, “CO ₂ -depleted exhaust gas” is also understood to mean carbonation vapors. “CO ₂ -depleted exhaust gas” is preferably understood to mean an exhaust gas obtained in a carbonation step. “CO ₂ -depleted exhaust gas” is preferably understood to mean a CO ₂ -depleted exhaust gas which is obtained after a reaction of CO ₂ present in a CO ₂ -enriched carbonation gas with calcium hydroxide present in an alkaline carbonation educt to form calcium carbonate. The CO ₂ -depleted exhaust gas is preferably discharged in a carbonation step according to method step b) according to the invention from an alkaline carbonation intermediate or carbonation product present in a carbonation container. According to the invention, the CO ₂ -depleted exhaust gas discharged from an alkaline carbonation intermediate product or carbonation product present in a carbonation container according to process step b) is preferably discharged into an in an alkaline carbonation educt present in a carbonation container upstream of the carbonation container is introduced as CO ₂ -enriched carbonation gas according to process step c) according to the invention. According to method step c) according to the invention, the CO ₂ -depleted exhaust gas discharged from a second carbonation container is preferably converted into an alkaline carbonation educt present in a first carbonation container as CO ₂ -enriched carbonation gas, in particular in addition to CO obtained in a lime kiln or present at least in part in a boiler house gas ₂ enriched carbonation gas, initiated. According to method step c) according to the invention, the CO ₂ -depleted exhaust gas discharged from a second carbonation container is preferably introduced into an alkaline carbonation educt present in a precarbonatation container as a CO ₂ -enriched carbonation gas, in particular as a single, sole CO ₂ -enriched carbonation gas.

In the context of the present invention, “fresh CO ₂ -enriched carbonation gas” is understood to mean a carbonation gas that is obtained by a lime kiln, in particular a coke- or gas-operated one, or that is at least partially present in a boiler house gas as CO ₂ -enriched carbonation gas that is not already in one Carbonation step was used. “Fresh CO ₂ -enriched carbonation gas” is preferably understood to mean a CO ₂ -enriched carbonation gas, which cannot also be understood as a CO ₂ -depleted exhaust gas, in particular obtained from a carbonation step.

In connection with the present invention, “CO ₂ content” is also understood to mean CO ₂ concentration. “CO ₂ -G” is preferably understood to mean the CO ₂ volume fraction of a gas based on the total volume of the gas.

In the context of the present invention, “pre-carbonatation step” is understood to mean a carbonation step that is carried out before the first carbonation step and in which a CO ₂ -depleted exhaust gas from a further, in particular second, carbonation step is used as the only CO ₂ -enriched carbonation gas in an alkaline carbonation educt is initiated.

In the context of the present invention, “at least one further carbonation step” is understood to mean at least one further carbonation step which is or are carried out after the first carbonation step. Preferably, the at least one further carbonation step is a second carbonation step and no further carbonation step is carried out after the second carbonation step.

In the context of the present invention, “beet sugar or sugar cane sugar processing device” is understood to mean a device that processes beet and/or sugar cane sugar into raw sugar. The method according to the invention is preferably carried out in the beet sugar or sugar cane sugar processing device according to the invention. Thin juice is preferably produced from sugar raw juice in the beet sugar or sugar cane sugar processing device. The beet sugar or sugar cane sugar processing device according to the invention preferably comprises a first carbonation container, at least one further carbonation container and at least one line from the at least one further carbonation container into an upstream carbonation container, wherein the at least one line is suitable for at least part of an exhaust gas from the at least one further carbonation container into an alkaline raw juice present in an upstream carbonation container. The beet sugar or sugar cane sugar processing device according to the invention preferably has an alkalinization container.

In the context of the present invention, “sugar refining device” is understood to mean a device that refines raw sugar into refined sugar. The process according to the invention is preferably carried out in the sugar refining device according to the invention. According to the invention, a purified raw sugar solution is preferably produced from a raw sugar solution in the sugar refining device according to the invention. The sugar refining device according to the invention preferably comprises a first carbonation container, at least one further carbonation container and at least one line from the at least one further carbonation container into an upstream carbonation container, the at least one line being suitable for carrying at least part of an exhaust gas from the at least one further carbonation container into an alkaline one In this case, raw sugar solution is introduced into an upstream carbonation container. The sugar refining device according to the invention preferably has an alkalinization container.

In the context of the present invention, “carbonatation container” is understood to mean a container in which a carbonation step is carried out. “Carbonation container” is preferably also understood to mean carbonation reactor. An alkaline carbonation reactant, an alkaline carbonation intermediate or a carbonation product is preferably present in a carbonation container. A separation device is preferably connected downstream of a carbonation container. Preferably, a CO ₂ -enriched carbonation gas is introduced into a carbonation container via a line and a CO ₂ -depleted exhaust gas is discharged via a further line.

In the context of the present invention, “pre-carbonatation container” is understood to mean a container in which a pre-carbonatation step is carried out, in particular in which a CO ₂ -depleted exhaust gas from a further, in particular second, carbonation step or further, in particular second, carbonation container is converted into an alkaline one as the only carbonation gas Carbonation educt is initiated.

wobei der Wert des CO₂-Gases dem CO₂-Gehalt im CO₂-angereicherten Carbonatationsgas (bezogen auf Gesamtvolumen CO₂-angereichertes Carbonatationsgas) und der Wert des CO₂-Abgases dem CO₂-Gehalt im CO₂-abgereicherten Abgas des Carbonatationsschritts (bezogen auf Gesamtvolumen CO₂-abgereichertes Abgas) entspricht.In connection with the present invention, the “gas utilization ratio” of a carbonation step is calculated using the following formula: $$10000*\left(\left({\text{CO}}_2-\text{gas}-{\text{CO}}_2-\text{exhaust}\right)/\left({\text{CO}}_2-\text{gas}*\left(100-{\text{CO}}_2-\text{exhaust}\right)\right)\right),$$

where the value of the CO ₂ gas corresponds to the CO ₂ content in the CO ₂ -enriched carbonation gas (based on the total volume of CO ₂ -enriched carbonation gas) and the value of the CO ₂ exhaust gas corresponds to the CO ₂ content in the CO ₂ -depleted exhaust gas of the carbonation step (based on the total volume of CO ₂ -depleted exhaust gas).

In connection with the present invention, “CO ₂ total gas utilization ratio” is understood to mean the total gas utilization ratio of the carbonation according to the invention and is calculated using the following formula: $$\begin{array}{l}100-(((\text{In total}-{\text{CO}}_2-\text{content in the exhaust gases}\left[\text{kg}/\text{H}\right])/(\text{Total}-{\text{CO}}_2-\text{Content in lime kiln gas}\\ \left[\text{kg}/\text{H}\right]))*100).\end{array}$$

If quantitative information, in particular percentages, of components of a product or a composition are given in connection with the present invention, these are added together with the other explicitly stated or expertly obvious further components of the composition or composition, unless explicitly stated otherwise or apparent to the expert Product to 100% of the composition and/or the product.

In the context of the present invention, the term “at least one” is understood to mean a quantity that expresses a number of 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 and so on. In a particularly preferred embodiment, the term “at least one” can represent exactly the number 1. In a further preferred embodiment, the term “at least one” can also mean 2 or 3 or 4 or 5 or 6 or 7.

If a “presence”, “containment”, “having” or “content” of a component is expressly mentioned or implied in connection with the present invention, this means that the respective component is present, in particular is present in a measurable amount.

If, in connection with the present invention, a “presence”, “containment” or “having” of a component in an amount of 0 [unit], in particular mg/kg, µg/kg or wt.%, is expressly mentioned or implied This means that the respective components are not present in measurable quantities, in particular not present.

The number of decimal places specified corresponds to the precision of the measurement method used.

If the first and second decimal places or the second decimal place are not specified for a number in connection with the present invention, these must be set as zero.

In connection with the present invention, the term “and/or” is understood to mean that all members of a group which are connected by the term “and/or” are disclosed both alternatively to one another and cumulatively with one another in any combination. For the expression “A, B and/or C”, this means that the following disclosure content is to be understood: a) A or B or C or b) (A and B), or c) (A and C), or d ) (B and C), or e) (A and B and C).

In connection with the present invention, the terms “comprising” and “having” mean that, in addition to the elements explicitly covered by these terms, there may be additional elements not explicitly mentioned. In the context of the present invention, these terms also mean that only the explicitly mentioned elements are recorded and no further elements are present. In this particular embodiment, the meaning of the terms “comprising” and “comprising” is synonymous with the term “consisting of”. In addition, the terms “comprising” and “comprising” also include compositions that, in addition to the explicitly named elements, also contain other elements not mentioned, but which are of a functional and qualitatively subordinate nature. In this embodiment, the terms “comprising” and “comprising” are synonymous with the term “consisting essentially of.”

Further advantageous refinements result from the subclaims.

The invention is described in more detail below without restricting the general inventive concept using examples and associated drawings.

List of reference symbols:

100

Comparison device

200

Device according to the invention

101, 201

Alkalization container

202

Pre-carbonatation tank

103, 203

first carbonation container

104, 204

second carbonation container

110, 210

Filtering device

111, 211

storage container

120, 220

supply line

130, 230

Line transporting fresh CO ₂ -enriched carbonation gas

131, 231

Exhaust pipe

240

Line according to the invention

241

Exhaust pipe

• 1 einen schematischen Aufbau einer Vergleichsvorrichtung (100), in dem kein erfindungsgemäßes Verfahren durchgeführt werden kann,
• 2 ein Balkendiagramm, das drei CO₂-Gasnutzungsgrade von drei ersten Carbonatationsschritten zeigt, bei denen drei verschiedene CO₂-Gehalte, 41,5 Vol.-%, 30,1 Vol.-% oder 26,0 Vol.-% (jeweils bezogen auf Gesamtvolumen Carbonatationsgas) aufweisende CO₂-angereicherte Carbonatationsgase verwendet wurden,
• 3 ein Balkendiagramm, das CO₂-Gasnutzungsgrade von drei zweiten Carbonatationsschritten zeigt, bei denen drei unterschiedliche CO₂-Gehalte, 41,5 Vol.-%, 30,1 Vol.-% oder 26,0 Vol.-% (jeweils bezogen auf Gesamtvolumen Carbonatationsgas) aufweisende CO₂-angereicherte Carbonatationsgase verwendet wurden,
• 4 einen schematischen Aufbau einer erfindungsgemäßen Vorrichtung (200), in dem ein erfindungsgemäßes Verfahren durchgeführt werden kann, und
• 5 ein Diagramm, das CO₂-Gasnutzungsgrade von vier Vorcarbonatationsschritten bei unterschiedlichen Retentionszeiten, 10, 8, 6, 4 und 2,5 Minuten, des CO₂-angereicherten Carbonatationsgases im Vorcarbonatationsbehälter zeigt, bei denen vier unterschiedliche CO₂-Gehalte, 41,5 Vol.-%, 35,0 Vol.-%, 30,0 Vol.-% und 26,0 Vol.-% (jeweils bezogen auf Gesamtvolumen Carbonatationsgas) aufweisende CO₂-angereicherte Carbonatationsgase verwendet wurden.

The figures show:

• 1 a schematic structure of a comparison device (100) in which no method according to the invention can be carried out,
• 2 a bar chart showing three CO ₂ gas utilization levels from three first carbonation steps, in which three different CO ₂ contents, 41.5 vol.-%, 30.1 vol.-% or 26.0 vol.-% (each based CO ₂ -enriched carbonation gases containing CO 2 (based on the total volume of carbonation gas) were used,
• 3 a bar chart showing CO ₂ gas utilization levels of three second carbonation steps, in which three different CO ₂ contents, 41.5 vol.-%, 30.1 vol.-% or 26.0 vol.-% (each based on Total volume of carbonation gas) containing CO ₂ -enriched carbonation gases were used,
• 4 a schematic structure of a device (200) according to the invention, in which a method according to the invention can be carried out, and
• 5 a diagram showing CO ₂ gas utilization levels of four precarbonatation steps at different retention times, 10, 8, 6, 4 and 2.5 minutes, of the CO ₂ -enriched carbonation gas in the precarbonatation container, in which four different CO ₂ contents, 41.5 % by volume, 35.0% by volume, 30.0% by volume and 26.0% by volume (in each case based on the total volume of carbonation gas) containing CO ₂ -enriched carbonation gases were used.

Examples:

Example 1: CO ₂ gas utilization levels of a first and a second carbonation step as a comparative example

In 1 a comparison device (100) is shown. After the alkalinization of sugar raw juice to obtain an alkaline sugar raw juice in an alkalinization container (101) (alkalinity 0.75 g CaO/100 ml), three carbonation ions each comprising two carbonation steps, in particular the first and second carbonation step, with CO having different CO ₂ contents ₂ -enriched carbonation gas, and the CO ₂ gas utilization rate was calculated and compared with each other. Process step c) according to the invention was not carried out.

The three CO ₂ -enriched carbonation gases with different CO ₂ contents were produced using a coke-operated lime kiln and by adding air. The CO ₂ content of the three CO ₂ -enriched carbonation gases was determined to be 41.5% by volume, 30.1% by volume and 26% using a gas analyzer, which analyzes the CO ₂ contents using a non-dispersive infrared sensor. 0% by volume (based on the total volume of carbonation gas). The three CO ₂ -enriched carbonation gases are referred to below as 41.5% CO ₂ gas, 30.1% CO ₂ gas and 26.0% CO ₂ gas or generally as CO ₂ gases.

The analysis of the CO ₂ gases was carried out using a Gas Analyzer Horiba Pg350 and the NDIR method (non-dispersive infrared sensor).

The respective CO ₂ -enriched carbonation gases are passed via a line (130) transporting fresh CO ₂ -enriched carbonation gas to the respective carbonation container and into the corresponding alkaline raw sugar juice. The alkaline raw sugar juice is transported via supply lines (120) between the respective containers or the filtering device (110), which is connected downstream of the first carbonation container (103) and upstream of a storage container (111).

wobei der Wert des CO₂-Gases dem CO₂-Gehalt im CO₂-angereicherten Carbonatationsgas des jeweiligen Carbonatationsschritts (bezogen auf Gesamtvolumen CO₂-angereichertes Carbonatationsgas) und der Wert des CO₂-Abgases dem CO₂-Gehalt im CO₂-abgereicherten Abgas des jeweiligen Carbonatationsschritts (bezogen auf Gesamtvolumen CO₂-abgereichertes Abgas) entspricht.A first carbonation step was carried out with the three CO ₂ gases in a first carbonation container (103) and then a second carbonation step with fresh CO ₂ gas in a second carbonation container (104) and the respective CO ₂ content of the CO ₂ -depleted The exhaust gas obtained in the respective carbonation step is measured and the CO ₂ gas utilization rate is calculated using the following formula: $$1000*\left(\left({\text{CO}}_{\text{2}}-\text{gas}-{\text{CO}}_{\text{2}}-\text{exhaust}\right)/\left({\text{CO}}_{\text{2}}-\text{Gas*}\left(\text{100}-{\text{CO}}_{\text{2}}-\text{exhaust}\right)\right)\right),$$

where the value of the CO ₂ gas corresponds to the CO ₂ content in the CO ₂ -enriched carbonation gas of the respective carbonation step (based on the total volume of CO ₂ -enriched carbonation gas) and the value of the CO ₂ exhaust gas corresponds to the CO ₂ content in the CO ₂ -depleted Exhaust gas from the respective carbonation step (based on the total volume of CO ₂ -depleted exhaust gas) corresponds.

The results are in Table 1 and 2 for the first carbonation step as well as Table 2 and 3 summarized for the second carbonation step.

Table 1 shows that with a lower CO ₂ content of the CO ₂ gas at the inlet of the first carbonation container of the first carbonation step, the CO ₂ content of the CO _2- depleted exhaust gas at the outlet of the first carbonation container of the first carbonation step decreases (second row, Table 1: 3.6 vol.%, 3.4 vol.% and 2.7 vol.% CO ₂ content in the exhaust gas of the 41.5 vol.% CO ₂ gas, 30.1 vol.% CO ₂ gas and 26.0 vol.% CO ₂ gas). The CO ₂ gas utilization rate also decreases (third row Table 2: 95%, 92% and 91% CO ₂ gas utilization rate from 41.5% CO ₂ gas, 30.1% CO ₂ gas and 26.0% CO ₂ gas). Table 1: CO ₂ content in the CO ₂ -enriched carbonation gas at the inlet and CO ₂ -depleted exhaust gas at the outlet of the first carbonation container of the first carbonation step as well as calculated values of the CO ₂ gas utilization ratio. 1. Carbonation step 1. Carbonation step 1. Carbonation step CO ₂ content (input) vol.-% 41.5 30.1 26 CO ₂ content (output) [% by volume] 3.6 3.4 2.7 CO ₂ gas utilization rate [%] 95 92 92

In 2 a bar diagram is shown, with a bar showing the respective CO ₂ gas utilization rate (y-axis) of the first carbonation step using a CO ₂ -enriched carbonation gas (x-axis, 41.5% CO ₂ gas, 30.1% CO ₂ gas and 26.0% CO ₂ gas). The CO ₂ gas utilization rate of the first carbonation step in which the 41.5% CO ₂ gas was used is 95%, that of the first carbonation step in which the 30.1% CO ₂ gas was used is 92% and the of the first carbonation step, in which the 26.0% CO ₂ gas was used, is 92%.

A lower CO ₂ content of the CO ₂ gas in the first carbonation step leads to a lower CO ₂ gas utilization rate in the first carbonation step. The same behavior can be seen in the second carbonation step (Table 2 and 3 ). In the second carbonation step, the CO ₂ content of the CO ₂ -depleted exhaust gas at the outlet of the second carbonation container is also lower with a lower CO ₂ content of the CO ₂ gas at the inlet of the second carbonation container. The CO ₂ gas utilization rate decreases as the CO ₂ content of the CO ₂ gas decreases. Table 2: CO ₂ content in the CO ₂ -enriched carbonation gas at the inlet and CO ₂ -depleted exhaust gas at the outlet of the second carbonation container of the second carbonation step as well as calculated values of the CO ₂ gas utilization ratio. 2. Carbonation step 2. Carbonation step 2. Carbonation step CO ₂ content (input) [% by volume] 41.5 30.1 26.0 CO ₂ content (output) [% by volume] 26.3 17.9 15.7 CO ₂ gas utilization rate [%] 50 49 47

In 3 a bar diagram is shown, with a bar representing the respective CO ₂ gas utilization rate (y-axis) of the second carbonation step, each using a CO ₂ -enriched carbonation gas (x-axis, 41.5% CO ₂ gas, 30.1% CO ₂ gas and 26.0% CO ₂ gas). The CO ₂ gas utilization rate of the second carbonation step in which the 41.5% CO ₂ gas was used is 50%, that of the second carbonation step in which the 30.1% CO ₂ gas was used is 49% and that of the second carbonation step using the 26.0% CO ₂ gas is 47%.

Table 3 shows the total gas volume of the CO ₂ gases used in the carbonation ions as well as the volume distribution of the respective total gas volume of the CO ₂ gas between the first and second carbonation steps. The last two lines of Table 3 show the CO ₂ consumption and the exhaust gas volume of the second carbonation step in m ³ . Table 3: Carbonation gas volume and exhaust gas volume of the carbonation ions CO ₂ content (input) [% by volume] 41.5 35.0 30.1 26.0 Total lime kiln gas volume for carbonation [m ³ /h] 2900 3500 4200 5200 Lime kiln gas volume of the first carbonation step [m ³ /h] 2470 2980 3593 4470 Lime kiln gas volume second carbonation step [m ³ /h] 430 520 607 730 CO ₂ consumption second carbonation step [m ³ /h] 89 89 89 89 Exhaust gas from the second carbonation step [m ³ /h] 341 431 518 641

Example 2: CO ₂ gas utilization levels and CO ₂ total gas utilization levels of a method according to the invention in a device according to the invention

In Example 2, after obtaining alkaline sugar raw juice according to process step a) of the present invention, a carbonation according to process step b) of the present invention comprising a precarbonatation step, a first and a second carbonation step and a process step c) according to the invention were carried out in a device according to the invention (200 ) according to 4 carried out.

4 shows a device (200) according to the invention. According to the device (200) according to the invention, an alkalinization container (201) (alkalinity 0.75 g CaO/100 ml), in which method step a) is carried out according to the method according to the invention, is a pre-carbonatation container (202), in which a pre-carbonatation step b0) is carried out according to The process according to the invention is carried out downstream, the alkalinization container (201) being connected to the pre-carbonatation container (202) via a feed line (220) through which the alkaline carbonation educt or alkaline carbonation intermediate product is transferred. The precarbonatation container (202) is followed by a first carbonation container (203), in which a first carbonation step b1) is carried out according to the method according to the invention, the precarbonatation container (202) being connected to the first carbonation container (203) via a supply line (220). , in which there is an alkalinity of 0.73 g CaO/100 ml at this position. A filtering device (210) is connected downstream of the first carbonation container (203), the first carbonation container (203) being connected to the filtering device (210) via a supply line (220). The filtering device (210) is followed by a storage container (211), the filtering device (210) being connected to the storage container (211) via a supply line (220). The storage container (211) is followed by a second carbonation container (204), in which a second carbonation step b2) is carried out according to the method according to the invention, the storage container (211) being connected to the second carbonation container (204) via a supply line (220). . Fresh CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt present in the first carbonation container (203) via a line (230) transporting a fresh CO ₂ -enriched carbonation gas and CO ₂ -depleted exhaust gas is discharged via an exhaust line (231). Fresh CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt present in the second carbonation container (204) via a line (230) transporting fresh CO ₂ -enriched carbonation gas, and the CO ₂ -depleted exhaust gas from the second carbonation container (240) is introduced via a line (240) according to the invention. 204 _{) .}

Fresh CO ₂ -enriched carbonation gases were used for the first and second carbonation steps, with the CO ₂ contents of the CO ₂ -enriched carbonation gases of the first and second carbonation steps being 41.5% by volume, 35.0% by volume, respectively. 30.0% by volume and 26.0% by volume (based on the total volume of carbonation gas). According to the invention, the CO ₂ -depleted exhaust gas obtained from the second carbonation step was discharged from the second carbonation container (204) into an alkaline sugar raw juice present in the precarbonatation container (201) as the sole and exclusive CO ₂ -enriched carbonation gas (CO ₂ gas) according to method step c according to the invention ) initiated, a pre-carbonatation step was carried out and a CO _2- depleted exhaust gas was discharged from the pre-carbonatation container (201).

wobei der Wert des CO₂-Gases dem CO₂-Gehalt im CO₂-angereicherten Carbonatationsgas des Vorcarbonatationsschritts (bezogen auf Gesamtvolumen CO₂-angereichertes Carbonatationsgas) und der Wert des CO₂-Abgases dem CO₂-Gehalt im CO₂-abgereicherten Abgas des Vorcarbonatationsschritts (bezogen auf Gesamtvolumen CO₂-abgereichertes Abgas) entspricht.The CO ₂ content of the CO ₂ -depleted exhaust gas of the second carbonation step, which represents the CO ₂ -enriched carbonation gas of the precarbonatation step (hereinafter referred to as CO ₂ gas), was 26.3% by volume, 21.4% by volume. -%, 17.9 vol.-% and 15.7 vol.-% (based on the total gas volume of CO ₂ -depleted exhaust gas of the second carbonation step or of the CO ₂ -enriched carbonation gas of the pre-carbonatation step), in particular by means of a gas analyzer which contains the CO ₂ -Contents analyzed and determined using a non-dispersive infrared sensor. This was transferred via a line (240) from the second carbonation container into an alkaline sugar raw juice present in the precar bonation container (201) is introduced as the sole and exclusive CO ₂ -enriched carbonatation gas and a pre-carbonatation step is carried out (see 4 ). The retention time of the respective CO ₂ gas in the precarbonatation container (201) during the precarbonatation step was 10, 8, 6, 4 or 2.5 minutes. The CO ₂ content of the CO ₂ -depleted exhaust gas from the precarbonatation step (hereinafter referred to as CO ₂ exhaust gas) was then determined and the CO ₂ gas utilization rate was calculated using the following formula: $$10000*\left(\left({\text{CO}}_2-\text{gas}-{\text{CO}}_2-\text{exhaust}\right)/\left({\text{CO}}_2-\text{gas}*\left(100-{\text{CO}}_2-\text{exhaust}\right)\right)\right),$$

where the value of the CO ₂ gas corresponds to the CO ₂ content in the CO ₂ -enriched carbonation gas of the precarbonatation step (based on the total volume of CO ₂ -enriched carbonation gas) and the value of the CO ₂ exhaust gas corresponds to the CO ₂ content in the CO ₂ -depleted exhaust gas of the precarbonatation step (based on the total volume of CO ₂ -depleted exhaust gas).

The respective CO ₂ gas utilization levels are in 5 summarized.

In 5 a diagram is shown in which one data point corresponds to a CO ₂ gas utilization rate (y-axis) of a pre-carbonatation step with a corresponding retention time (x-axis) of the CO ₂ -enriched carbonation gas during the pre-carbonatation step in a pre-carbonatation container (201).

The calculations and the diagram in 5 show that the CO ₂ gas utilization rate of the precarbonatation step according to the invention is ≥80%.

5 also shows the tendency that the CO ₂ gas utilization rate in the precarbonatation step according to the invention, in particular with a retention time of 8 minutes, decreases with an increase in the CO ₂ content in the CO ₂ -enriched carbonation gas. Next is in 5 There is a tendency to see that the CO ₂ gas utilization rate in the precarbonatation step according to the invention decreases with a lower retention time.

• - Der CO₂-Gehalt im CO₂-abgereicherten Abgas des Vorcarbonatationsschritts beträgt von 2,5 bis 5,5 Vol.-% (bezogen auf Gesamtvolumen CO₂-Abgas).
• - Der CO₂-Gehalt im CO₂-abgereicherten Abgas des Vorcarbonatationsschritts verringert sich mit der Verringerung des CO₂-Gehalts im CO₂-angereicherten Carbonatationsgas des Vorcarbonatationsschritts. Der CO₂-Gehalt im CO₂-abgereicherten Abgas des Vorcarbonatationsschritts verringert sich mit der Zunahme der Retentionszeit des CO₂angereicherten Carbonatationsgases im Vorcarbonatationsbehälter (201) während des Vorcarbonatations schritts.
• - Die Alkalität im alkalischen Zuckerrohsaft eingesetzt im erfindungsgemäßen Vorcarbonatationsschritt reduzierte sich um 0,02 g CaO/100 mL (von 0,75 g CaO/100 mL auf 0,73 g CaO/100 mL).

Example 2 shows in particular:

• - The CO ₂ content in the CO ₂ -depleted exhaust gas from the precarbonatation step is from 2.5 to 5.5% by volume (based on the total volume of CO ₂ exhaust gas).
• - The CO ₂ content in the CO ₂ -depleted exhaust gas of the precarbonatation step decreases as the CO ₂ content in the CO ₂ -enriched carbonation gas of the precarbonatation step decreases. The CO ₂ content in the CO ₂ -depleted exhaust gas from the precarbonatation step decreases with the increase in the retention time of the CO ₂ -enriched carbonation gas in the precarbonatation container (201) during the precarbonatation step.
• - The alkalinity in the alkaline raw sugar juice used in the precarbonatation step according to the invention reduced by 0.02 g CaO/100 mL (from 0.75 g CaO/100 mL to 0.73 g CaO/100 mL).

Example 3: Comparison of the results from Example 1 and Example 2

Table 4 compares the CO ₂ gas utilization rates and CO ₂ total gas utilization rates of the example according to the invention (Example 2) and the comparative example (Example 1). According to the invention (Example 2) Comparison (Example 1) CO ₂ content in the lime kiln gas % 41.5 30.1 26.0 41.5 30.1 26.0 Total lime kiln gas per hour ^m3 /h 2900 4200 5200 2900 4200 5200 CO ₂ density kg/ ^m3 1.98 1.98 1.98 1.98 1.98 1.98 Total CO ₂ content in the lime kiln gas kg/h 2383 2503 2677 2383 2503 2708 Lime kiln gas in the 1st carbonation step ^m3 /h 2470 3593 4470 2470 3593 4470 CO ₂ content in the lime kiln gas in the 1st carbonation step kg/h 2030 2141 2301 2030 2141 2328 CO ₂ gas utilization rate of the 1st carbonation step % 95 92 92 95 92 92 CO ₂ content in the exhaust gas from the 1st carbonation step kg/h 101 171 184 101 171 186 Lime kiln gas in the 2nd carbonation step ^m3 /h 430 607 730 430 607 730 CO ₂ content in the lime kiln gas in the 2nd carbonation step kg/h 353 362 376 353 362 380 CO ₂ gas utilization rate of the 2nd carbonation step % 50 49 47 50 49 47 CO ₂ content in the exhaust gas from the 2nd carbonation step kg/h 177 184 199 177 184 201 Exhaust gas from the 2nd carbonation step for the pre-carbonatation step ^m3 /h 341 517 641 - - - CO ₂ content in the carbonation gas of the precarbonatation step % 26.3 17.9 15.7 - - - CO ₂ content in the carbonation gas of the precarbonatation step kg/h 177 183 199 - - - CO ₂ gas utilization rate of the precarbonatation step (average of the residence times from 2.5 to 10 min) % 84.5 83.4 83.2 - - - CO ₂ content in the exhaust gas from the precarbonatation step kg/h 28 30 33 - - - Total CO ₂ content (i.e. emission) in the exhaust gases from carbonation kg/h 129 202 218 278 356 388 CO ₂ total gas utilization rate of carbonation % 95 92 92 88 86 86

From Table 4 it can be seen that the CO ₂ emission of the carbonation ions carried out according to the method according to the invention and in a device according to the invention in the carbonation with the 41.5-CO ₂ gas by 54%, with the 30.1-CO ₂ - Gas is reduced by 43% and with the 26.3-CO ₂ gas by 44%.

The CO ₂ total gas utilization rate of the respective carbonate ions is calculated using the following formula: $$\begin{array}{l}100-((\left(\text{In total}-{\text{CO}}_2-\text{content in the exhaust gases}\left[\text{kg}/\text{H}\right]\right)/(\text{In total}-{\text{CO}}_2-\text{Content in lime kiln gas}\\ \left[\text{kg}/\text{H}\right]))*100),\end{array}$$

The CO ₂ total gas utilization rate of the carbonation ions according to the method according to the invention and carried out in a device according to the invention is around 8% in the carbonation with the 41.5-CO ₂ gas, around 7% with the 30.1-CO ₂ gas and with the 26.3-CO ₂ gas improved by 7%.

It can therefore be seen that production of a carbonation product from a carbonation reactant by means of a method according to the invention, in particular carried out in a device according to the invention, compared to a comparison process, in particular carried out in a comparison device, results in a higher CO ₂ total gas utilization rate and a reduced CO ₂ emission having.

Claims (19)

Process for producing a carbonation product from a carbonation educt, comprising the process steps: a) alkalinization of a carbonation educt to obtain an alkaline carbonation educt and b) carbonation of the alkaline carbonation educt comprising a first and at least one further carbonation step b1) and b2) to obtain the carbonation product, in which a CO ₂ -enriched carbonation gas is introduced into the alkaline carbonation educt and a CO _2- depleted exhaust gas is discharged, characterized by c) introducing at least a portion of the exhaust gas from the at least one further carbonation step into the alkaline carbonation educt before or during the first carbonation step. Procedure according to Claim 1 , whereby a precarbonatation step b0) is carried out before the first carbonation step b1). Method according to one of the preceding claims, wherein the carbonation educt is a raw sugar juice and the carbonation product is a thin juice or the carbonation educt is a raw sugar solution and the carbonation product is a purified raw sugar solution. Method according to one of the preceding claims, wherein the at least a portion of the exhaust gas from the at least one further carbonation step from method step b) is introduced into the alkaline carbonation educt of the first carbonation step or the precarbonatation step according to method step c). Method according to one of the preceding claims, wherein the method is carried out in a device for producing a carbonation educt from a carbonation product comprising at least a first carbonation container (202) and at least one further carbonation container. Method according to one of the preceding claims, wherein the device (200) has a pre-carbonatation container (201) connected upstream of the first carbonation container (202). Method according to one of the preceding claims, wherein the device has at least one line (240) from the at least one further carbonation container to an upstream carbonation container, in particular first carbonation container (202) or pre-carbonatation container (201), in order to transport at least part of the exhaust gas of the at least one to initiate a further carbonation step into the alkaline carbonation educt before or during the first carbonation step. Method according to one of the preceding claims, wherein the exhaust gas from the at least one further carbonation step has a CO ₂ content of 1 to 40% by volume, in particular 15 to 27% by volume (based on the total volume of exhaust gas). Method according to one of the preceding claims, wherein the exhaust gas from the at least one further carbonation step is mixed with a CO ₂ -enriched carbonation gas after method step b) and before method step c). Method according to one of the preceding claims, wherein the CO ₂ -enriched carbonation gas is obtained by a coke- or gas-operated lime kiln or is at least a portion of a boiler house gas. Method according to one of the preceding claims, wherein the following Claim 9 obtained CO ₂ -enriched carbonation gas has a CO ₂ content of 1 to 99 vol.-% (based on the total volume of CO ₂ -containing gas). Method according to one of the preceding claims, wherein the carbonation educt is obtained from sugar beet or sugar cane. Method according to one of the preceding claims, wherein the CO ₂ gas utilization rate of the at least one further carbonation step is at least 20%. Method according to one of the preceding claims, wherein the CO ₂ total gas utilization rate of the carbonation is at least 70%. Device for producing a carbonation product from a carbonation educt, particularly suitable and designed for carrying out a method according to one of the preceding Claims 1 until 14 , comprising at least a first carbonation container (201), at least one further carbonation container and at least one line (240) from the at least one further carbonation container into an upstream carbonation container, which is suitable for at least part of an exhaust gas from the at least one further carbonation container into an alkaline one In the present case, carbonation educt is to be initiated in an upstream carbonation container. Device (200) after Claim 15 , wherein the first carbonation container (202) is preceded by a pre-carbonatation container (201). Device according to Claim 15 or 16 , wherein the upstream carbonation container is the first carbonation container (202) or the pre-carbonatation container (201). Device according to one of the Claims 15 until 17 , wherein the device is a beet sugar or sugar cane sugar processing device for producing thin juice from sugar raw juice. Device according to one of the Claims 15 until 17 , wherein the device is a sugar refining device for producing a purified raw sugar solution from a raw sugar solution.

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