Search

BR-112022005612-B1 - CONTINUOUS PROCESS

BR112022005612B1BR 112022005612 B1BR112022005612 B1BR 112022005612B1BR-112022005612-B1

Abstract

CONTINUOUS PROCESS. Through this invention, processes are provided for the conversion of carbohydrate to ethylene glycol by retroaldol catalysis and sequential hydrogenation using control methods that have at least one acetol (hydroxyacetone) and a tracer as inputs.

Inventors

  • Ray Chrisman
  • Donald Bunning
  • Brooke Albin
  • Mark Nunley
  • Michael Bradford
  • DAVID JAMES SCHRECK
  • Lou Kapicak

Assignees

  • T.EN PROCESS TECHNOLOGY, INC

Dates

Publication Date
20260317
Application Date
20200924
Priority Date
20190924

Claims (20)

  1. 1. Continuous process, characterized in that it has a control system to control one or more operational parameters based on one or more inputs for the catalytic conversion of a carbohydrate feed containing at least aldose- or ketose-producing carbohydrate into lower glycol of at least one ethylene glycol and propylene glycol in an unmodulated reaction zone by sequential retroaldol catalytic conversion under retroaldol conditions, which includes the presence of a retroaldol catalyst that provides retroaldol catalytic activity in a liquid medium in the unmodulated reaction zone, to intermediates and catalytic hydrogenation of intermediates under hydrogenation conditions, which includes the presence of hydrogen and a hydrogenation catalyst that provides hydrogenation catalytic activity, to lower glycol, in the unmodulated reaction zone and continuously or intermittently withdraws from said unmodulated reaction zone a crude product, said process comprising the control of at least one operational parameter of the process using a concentration of at least acetol in the crude product as an input to the system. process control.
  2. 2. Process according to claim 1, characterized in that the carbohydrate comprises aldose and the lower glycol comprises ethylene glycol.
  3. 3. Process according to claim 2, characterized in that, in response to an increase in acetol concentration, at least one of (i) the catalytic hydrogenation activity is increased and (ii) at least one of the carbohydrate feed supply rate and the carbohydrate concentration in the feed is decreased.
  4. 4. Process according to claim 2, characterized in that the retroaldol catalyst is homogeneous and the hydrogenation catalyst is heterogeneous.
  5. 5. Process according to claim 2, characterized in that the acetol concentration is compared with concentrations of at least one of itol, 1,2-butanediol and pH in the crude product for process control purposes.
  6. 6. Process according to claim 5, characterized in that, in response to an increase in the concentration of acetol and an increase in the concentration of at least one of sorbitol, 1,2-butanediol and glycerol in the crude product, the retroaldol catalytic activity is increased.
  7. 7. Process according to claim 2, characterized in that the concentration of hydroxyacetone is maintained below 0.15 percent by mass of the crude product.
  8. 8. Process according to claim 2, characterized in that, in response to an increase in acetol accompanied by an increase in at least one of mannitol and glycerol, at least one of the carbohydrate feed supply rate and the carbohydrate concentration in the feed is decreased until the retroaldol catalytic activity is increased.
  9. 9. Process according to claim 1, characterized in that the reaction zone is a cascade reaction zone.
  10. 10. Continuous process, characterized in that it has a control system to control one or more operating parameters based on the input for the catalytic conversion of a carbohydrate feed containing at least one aldose- or ketose-producing carbohydrate into lower glycol of at least one ethylene glycol and propylene glycol in an unmodulated reaction zone by sequential retroaldol catalytic conversion under retroaldol conditions, which includes the presence of a retroaldol catalyst that provides retroaldol catalytic activity in a liquid medium in the unmodulated reaction zone, to intermediates and catalytic hydrogenation of intermediates under hydrogenation conditions, which includes the presence of hydrogen and a hydrogenation catalyst that provides hydrogenation catalytic activity, to lower glycol, in the unmodulated reaction zone, providing a marker precursor comprising a 3- to 6-carbon ketone to the reaction zone from which at least one marker is produced under conditions in the reaction zone and continuously or intermittently withdrawing from said unmodulated reaction zone a crude product, being that said process comprises controlling at least one operational parameter of the process using at least the concentration of at least one component of the marker in the raw product as an input to the control system for processing it.
  11. 11. Process according to claim 10, characterized in that the marker in the crude product indicates a change in the portion of the hydrogenated marker precursor, so that at least one of (i) the absolute amounts of catalytically active species and the relative amounts of each of the retroaldol catalytic activities and catalytic hydrogenation, and (ii) at least one of the feed rate and carbohydrate concentration in the feed to the reaction zone are adjusted.
  12. 12. Process according to claim 11, characterized in that when the concentration of a marker in the crude product indicates that a larger portion of the marker precursor is hydrogenated, one or both of the following conditions occur: (i) the feed rate to the reaction zone is increased; or (ii) the activity of the hydrogenation catalyst in the reaction zone is decreased.
  13. 13. Process according to claim 11, characterized in that when the concentration of a marker in the crude product indicates that a smaller portion of the marker precursor is hydrogenated, one or both of the following conditions occur: (i) the activity of the hydrogenation catalyst in the reaction zone is increased; and (ii) at least one of the feed rate and the carbohydrate concentration in the feed to the reaction zone is decreased.
  14. 14. Process according to claim 10, characterized in that the retroaldol catalyst is homogeneous and the hydrogenation catalyst is heterogeneous.
  15. 15. Process according to claim 10, characterized in that the carbohydrate comprises aldose and the lower glycol comprises ethylene glycol, wherein the concentration of at least one component of the marker is compared with the concentration of at least one of itol, 1,2-butanediol, acetol and pH in the crude product for process control purposes.
  16. 16. Process according to claim 15, characterized in that the marker in the crude product indicates a substantially constant condition in the portion of the marker precursor that is hydrogenated and an increase in the concentration of at least one of sorbitol and glycerol in the crude product, thereby increasing the retroaldol catalytic activity.
  17. 17. Process according to claim 15, characterized in that when the marker in the crude product indicates a decrease in the portion of the marker precursor that is hydrogenated and no increase in the concentration of at least one of sorbitol, 1,2-butanediol and glycerol in the crude product, one or both of the following conditions occur: (i) the catalytic activity of hydrogenation is increased; and (ii) at least one of the feed rate and the carbohydrate concentration in the feed is decreased.
  18. 18. Process according to claim 10, characterized in that the process uses a hydrogenation catalyst that is removed from or intended to be used in a larger reaction zone to evaluate the catalytic hydrogenation activity.
  19. 19. Process according to claim 10, characterized in that the tracer precursor is added to solve process problems.
  20. 20. Process according to claim 10, characterized in that the tracer precursor comprises methyl ethyl ketone and the tracers comprise methyl ethyl ketone and isobutanol.

Description

CROSS-REFERENCE TO RELATED REQUEST(S) [001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application 62/905,068, filed September 24, 2019, and entitled METHODS FOR OPERATING CONTINUOUS, UNMODULATED, MULTIPLE CATALYTIC STEP PROCESSES, which is incorporated herein in its entirety by reference for all purposes. FIELD OF TECHNIQUE [002] This invention relates to processes for the catalytic conversion of carbohydrate into ethylene glycol via the retroaldol/hydrogenation route. BACKGROUND [003] Ethylene glycol is a valuable chemical that has a wide range of uses as a building block for other materials, such as polyethylene terephthalate (PET), and for its intrinsic properties, such as antifreeze. The demand for ethylene glycol is substantial, making it one of the highest volume organic chemicals produced in the world. Currently, it is made by multi-step processes that begin with ethylene derived from hydrocarbon feedstocks. [004] Proposals have been made to manufacture ethylene glycol from renewable resources, such as carbohydrates. These alternative processes include catalytic routes, such as sugar hydrogenolysis and a two-catalyst process using a retroaldol catalyst to generate sugar intermediates that can be hydrogenated over a hydrogenation catalyst to produce ethylene glycol and propylene glycol. [005] In the retroaldol pathway, carbohydrate is converted via a retroaldol catalyst into intermediates, and then the intermediates are catalytically converted over a hydrogenation catalyst into ethylene glycol and/or propylene glycol in an unmodulated reaction zone. As used in this document, the term unmodulated means that the process is conducted in a single vessel or, if in multiple vessels or regions, intermediates are not removed between vessels or zones. The retroaldol reaction that initially occurs is endothermic and requires a high temperature, for example, often above 230 °C, to provide a reaction rate sufficient to preferentially favor the conversion of carbohydrates into intermediates. Under conditions that favor retroaldol conversion, isomerization of sugars can occur. For example, aldoses, such as glucose, can be isomerized into fructose. Aldoses, like glucose, provide two-carbon intermediates under retroaldol conditions, such as glycol aldehyde, which can be hydrogenated to ethylene glycol. Fructose, under retroaldol conditions, is converted into, among other things, three-carbon intermediates that, under hydrogenation conditions, yield propylene glycol and glycerol. Furthermore, retroaldol intermediates, such as glycol aldehyde, can react to provide coproducts like 1,2-butanediol. Additionally, hydrogenation can result in the degradation of ethylene glycol and propylene glycol. Since hydrogen is necessary, the bulk transfer of hydrogen to catalytic sites may be inadequate to support hydrogenation, and this lack of hydrogen can result in the production of coproducts such as organic acids. Consequently, to optimize ethylene glycol production in an unmodulated reaction zone, the retroaldol conversion and hydrogenation conditions need to be in equilibrium. [006] There is therefore a desire to provide methods for controlling retroaldol/hydrogenation processes using an unmodulated reaction zone. Furthermore, it is desirable that such methods use input parameters that can be reasonably obtained from the process, especially input parameters that can be determined relatively quickly to provide real-time data on process operation. BRIEF SUMMARY [007] This invention provides processes for the conversion of carbohydrate to ethylene glycol by retroaldol catalysis and sequential hydrogenation using control methods that have at least one acetol (hydroxyacetone) and at least one tracer as inputs. A tracer precursor is one or more ketones of 3 to 6, preferably 4 to 6, carbons, and the tracer is one or more unreacted tracer precursors and hydrogenation products of the ketone, such as alcohols in the crude product resulting from the supply of the ketone to the reaction zone. The concentration of acetol in the crude product reflects both information about the relative amount of aldose isomerization and is a three-carbon compound derived from the retroaldol catalysis of fructose and hydrogenation. A carbonyl of a ketone does not undergo retroaldol conversion and therefore the tracer reflects the strength of hydrogenation. Since carbohydrate conversion does not result in the co-production of hydrocarbons containing only internal carbonyls or hydroxyls, the input based on one or more tracers is not mistaken as a co-product. Control systems useful for retroaldol conversion/carbohydrate hydrogenation to ethylene glycol will employ a number of other inputs, such as one or more of pressure, temperature, residence time, pH, crude product composition, feed compositions and rates, and the like. Acetol and/or tracer provide information not readily available about the process condition and therefo