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WO-2026093272-A1 - USE OF A HOLISTIC MODEL OF A BELT DRYER TO PREDICT PRODUCT PROPERTIES

WO2026093272A1WO 2026093272 A1WO2026093272 A1WO 2026093272A1WO-2026093272-A1

Abstract

The invention is directed to a method for controlling operation of a belt dryer assembly (500) for carrying out a drying process of a superabsorbent material cake (502) that results in an output material (512). The method comprises ascertaining a belt dryer model (M) indicative of a respective effect of drying process parameters (PP1, PP2) associated to the belt dryer assembly on physical and/or chemical properties (P1, P2) of the superabsorbent material cake, ascertaining output material data (518) indicative of respective values of one or more of the material properties (PV) of the output material, and using the belt dryer model and the received output material data, determining and providing control instructions (CIa) for controlling operation of the belt dryer assembly for driving the values of the physical and/or chemical properties of subsequent output material towards a set of expected values of the physical and/or chemical properties (P1*, P2*).

Inventors

  • DANIEL, THOMAS
  • POSSEMIERS, KARL
  • Buchholz, Moritz
  • PETERSON, MONTE ALAN
  • RAUPP, Sebastian Marius
  • ADEY, Vernon Lynn
  • VAN HEETVELDE, Bartholomeus
  • DE KAEY, RONNY
  • HELFENRITTER, Christoph
  • KROPFINGER, Lukas

Assignees

  • BASF SE

Dates

Publication Date
20260507
Application Date
20251028
Priority Date
20241101

Claims (20)

  1. CLAIMS
  2. 1. Computer implemented method (100) for controlling operation of a belt dryer assembly (500) for carrying out a drying process of a superabsorbent material cake (502) that results in an output material (512), the method comprising:
  3. - ascertaining (102) a belt dryer model (M) indicative of a respective effect of drying process parameters (PP1, PP2) associated to the belt dryer assembly on physical and/or chemical properties (P1, P2) of the superabsorbent material cake;
  4. - ascertaining (104) output material data (518) indicative of respective values of one or more of the physical and/or chemical properties (PV) of the output material after the drying process; and
  5. - using the belt dryer model and the ascertained output material data, determining and providing (106a) control instructions (Cla) for controlling operation of the belt dryer assembly for driving the values of the physical and/or chemical properties (PV) of subsequent output material towards a set of expected values of the physical and/or chemical properties (P1* p2 *)
  6. 2. The method (100) of claim 1, further comprising:
  7. - using the belt dryer model and the received output material data, determining and providing (106b) control instructions (Clb) for controlling operation of a pre-processing unit (510) for processing and feeding the superabsorbent material cake to the belt dryer assembly, for driving the values of physical and/or chemical properties of subsequent output material towards the set of expected values of the physical and/or chemical properties.
  8. 3. The method (100) of claim 1 or 2, further comprising: using the belt dryer model and the ascertained output material data, determining and providing (106c) control instructions (Clc) for controlling operation of a post-processing unit (523) for further processing the output material for driving the values of the physical and/or chemical properties of the output material towards the set of expected values of the physical and/or chemical properties.
  9. 4. The method of any of the preceding claims, wherein the step of determining and providing (106a, 106b, 106c) control instructions is performed using a machine learning model that has been trained using training data sets that represent a plurality of drying processes performed on superabsorbent material cakes having corresponding physical and/or chemical properties that result in output material having corresponding physical and/or chemical properties.
  10. 5. The method (100) of any of the preceding claims, further comprising:
  11. - determining (103), the respective values of the physical and/or chemical properties of the output material after the drying process.
  12. 6. The method (100) of any of the preceding claims, wherein the output material data indicative of the values of the physical and/or chemical properties of the output material after the drying process include one or more of chemical composition data indicative of a chemical composition of the output material after the drying process, moisture data indicative of a moisture content of the output material and particle size data indicative of a particle size distribution of the output material.
  13. 7. The method (100) of any of the preceding claims, wherein
  14. - the control instructions (Cla) for controlling operation of the belt dryer assembly are control instructions for controlling one or more of a gas inlet temperature value of a drying gas, a gas flow rate value of the drying gas, a belt dryer speed value of a belt, a fresh air inlet or an exhaust air outlet; and/or
  15. - the control instructions (Clb) for controlling operation of the pre-processing unit are control instructions for controlling one or more of an extruder unit, a polymerization unit, a gel bunker, or a superabsorbent material cake feeder unit for providing a desired distribution (e.g. height) of the superabsorbent material cake at an input of the belt dryer assembly; and/or
  16. - the control instructions (Clc) for controlling operation of post-processing unit are control instructions for controlling a milling unit for milling the dried superabsorbent material cake.
  17. 8. The method of any of the preceding claims, wherein the belt dryer assembly comprises a plurality of drying zones along a drying route, and wherein the method includes determining and providing respective control instructions (CI1-CIN) for controlling the different drying zones along the drying route. 9. The method of any of the preceding claim, wherein the belt dryer model comprises a gas-phase model including balance equations and constitutive equations for a gas phase, a solid phase model including balance equations and constitutive equations for a solid phase, an exchange flow model including heat exchange equations and mass exchange equations and a gas-solid interface model.
  18. 10. The method of any of the preceding claims, wherein, in the belt dryer model, the superabsorbent material cake is modelled as a discretized cake comprising, in particular per drying zone, one or more cake elements (EI1-EIN) in a horizontal direction and one or more layers of cake elements (Lay1-LayM) in a vertical direction, and wherein each cake element is associated to a size class (k) indicative of the mean particle size in said cake element.
  19. 11. A belt dryer assembly (500) for carrying out a drying process of a superabsorbent material cake (502), the belt drying assembly comprising:
  20. - a belt dryer (504) having an input unit (506) for receiving the superabsorbent material cake to be dried and comprising a belt (508) configured to transport the superabsorbent material cake from the input unit to an output unit (510) for providing a dried superabsorbent material cake (512);

Description

Use of a holistic model of a belt dryer to predict product properties FIELD OF THE INVENTION The invention is directed to a computer implemented method for controlling operation of a belt dryer assembly for carrying out a drying process of a superabsorbent material cake that results in an output material. The invention is further directed to a belt dryer assembly and to a computer program. BACKGROUND OF THE INVENTION Superabsorbent polymer, often referred to as SAP, is a water absorbent hydrophilic homopolymer or copolymer that can absorb and retain extremely large amounts of aqueous liquid relative to its own mass. They are typically produced by polymerization of a monomer so-lution. The polymer gel is then dried, typically using a belt dryer assembly until the residual moisture content is below a predetermined threshold amount. US 10,1137,432 B2 describes a process for producing water absorbing polymer particles that includes drying the aqueous polymer gel in a belt dryer assembly comprising a conveyer dryer, in particular in a forced air conveyer dryer, wherein the conveyer dryer has a circulating conveyer belt and the aqueous polymer gel is conveyed on the circulating conveyer belt. According to the document, the process stability can be improved by avoiding changes in process conditions, e.g., to overcome heat exchanger fouling in the dryer which changes the drying air throughputs. In current belt dryer assemblies, the operation parameters for the drying process are set by the operator based on his or her knowledge of the process or best product behavior. This learned behavior is cumbersome because in the drying process of gel there may be chemical degradation of the polymer observed depending on drying conditions, the morphology of the gel particles, and the composition of gel particles. Therefore, the drying step is critical to overall performance of the finished product and customer acceptance. Hence, a product specific drying operation is desirable which requires smart process control. One example of this is disclosed in WO2023/046583A1. As in modern production for superabsorbents it is not only necessary to enable easy switching between product grades but also to control process settings and formulation tightly to achieve target performance, prevent product loss, and enable high productivity there exists a need for better and holistic production process control. SUMMARY OF THE INVENTION It would be therefore beneficial to enable an improvement of the physical and/or chemical properties of the output material obtained after the drying process. A first aspect of the present invention is formed by a computer implemented method for controlling operation of a belt dryer assembly for carrying out a drying process of a superabsorbent material cake that results in an output material, namely a dried superabsorbent material cake with lower moisture content than the superabsorbent material cake fed into the belt dryer assembly. The method of the first aspect comprises ascertaining (e.g., determining, receiving, generating, or otherwise acquiring) a belt dryer model indicative of a respective effect of drying process parameters associated to the belt dryer assembly on physical and/or chemical properties of the superabsorbent material cake, ascertaining output material data indicative of respective values of one or more of the physical and/or chemical properties of the output material after the drying process, and using the belt dryer model and the ascertained output material data, determining and providing control instructions for controlling operation of the belt dryer assembly for driving the values of the physical and/or chemical properties of subsequent output material towards a set of expected values of the physical and/or chemical properties. Thus, the provision of the belt dryer model, which relates the operation of the belt dryer assembly to material properties of the superabsorbent material cake, in combination with the output material data obtained from the output material, i.e. the dried superabsorbent material cake, opens a feedback loop to control the material properties (e.g. the chemical and/or physical properties) of subsequent output material. The belt dryer model refers to a description of the drying process in the belt dryer assembly using mathematical concepts including governing equations, assumptions and constraints. The output material data is correlated or associated to the drying process parameters used to obtain the output material. The feedback loop to control the material properties is achieved by controlling one or more variables that affect the drying process, so that the values of the physical and/or chemical properties of subsequent output material are driven towards the set of predetermined expected values, also referred to as target values, and which can be given as exact values or as value ranges exhibiting a certain tolerance around a respective center value. Thus, in