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EP-4735558-A1 - CATALYTIC AROMATIZATION OF PYROLYSIS VAPORS

EP4735558A1EP 4735558 A1EP4735558 A1EP 4735558A1EP-4735558-A1

Abstract

The invention is in the field of catalytic processes. In particular the present invention is directed to a thermo-catalytic pyrolysis process for the preparation of low molecular weight monocyclic aromatic compounds. In accordance with the present invention there is provided a thermo-catalytic pyrolysis process for the preparation of low molecular weight monocyclic aromatic compounds from a feed stream comprising biomass and/or one or more polymers, comprising the steps of: a) subjecting the feed stream comprising biomass and/or one or more polymers to a pyrolysis treatment at a pyrolysis temperature to produce pyrolysis vapors; b) optionally cooling or heating the pyrolysis vapors; c) contacting the pyrolysis vapors with an aromatization catalyst at an aromatization temperature in a catalytic conversion step to yield a conversion product comprising low molecular weight aromatic compounds; and d) optionally recovering the low molecular weight monocyclic aromatic compounds from the conversion product; wherein catalytic conversion step c) is performed in a smooth or bubbling fluidized bed reactor.

Inventors

  • SCHENK, Niels Jan
  • VAN AKKER, Matthijs Geert

Assignees

  • Biobtx B.V.

Dates

Publication Date
20260506
Application Date
20240628

Claims (15)

  1. 1. A thermo-catalytic pyrolysis process for the preparation of low molecular weight monocyclic aromatic compounds from a feed stream comprising biomass and/or one or more polymers, comprising the steps of: a) subjecting the feed stream comprising biomass and/or one or more polymers to a pyrolysis treatment at a pyrolysis temperature to produce pyrolysis vapors; b) optionally cooling or heating the pyrolysis vapors; c) contacting the pyrolysis vapors with an aromatization catalyst at an aromatization temperature in a catalytic conversion step to yield a conversion product comprising low molecular weight aromatic compounds; and d) optionally recovering the low molecular weight monocyclic aromatic compounds from the conversion product; wherein catalytic conversion step c) is performed in a smooth or bubbling fluidized bed reactor.
  2. 2. Process according to claim 1, wherein pyrolysis step a) and catalytic conversion step c) take place in two different reactors.
  3. 3. Process according to claim 1 or 2, wherein step c) further yields carbonaceous deposits on the aromatization catalyst, and wherein step c) further comprises the steps of: cl) extracting a fraction of the aromatization catalyst comprising carbonaceous deposits from the aromatization reactor thereby creating a catalyst circulation stream; c2) separating entrained fluid from the aromatization catalyst comprising carbonaceous deposits of the catalyst circulation stream, preferably using a stripper; c3) regenerating the aromatization catalyst in a regenerator, wherein the regenerator is preferably also a smooth or bubbling fluidized bed reactor; c4) feeding regenerated aromatization catalyst to the aromatization reactor; thereby obtaining circulation of aromatization catalyst; thereby obtaining circulation of the aromatization catalyst.
  4. 4. Process according to claim 3, wherein the total amount of aromatization catalyst in the aromatization reactor is circulated 0.2-20 times per hour, preferably 0.5-15 times per hour, more preferably 1-10 times per hour.
  5. 5. Process according to any one of claims 1-4, wherein the weight hourly space velocity is 0.1-10.0 h 1 , preferably 0.5-2.0 h 1 , more preferably 0.7- 1.5 h 1 .
  6. 6. Process according to any one of claims 1-5, wherein the superficial velocity of the pyrolysis vapors in the aromatization reactor is 0.005 m/s or more, preferably 0.01 to 1.0 m/s, more preferably 0.02 to 0.8 m/s.
  7. 7. Process according to any one of claims 1-6, wherein the aromatization catalyst comprises a plurality of Geldart type A solid catalyst particles.
  8. 8. Process according to any one of claims 1-7, wherein the aromatization catalyst comprises a plurality of solid catalyst particles having an average particles size of 1-150 jim, preferably, 20-120 jim, such as 30-100 pm, and/or a bulk density of 500-1300 kg/m 3 , preferably 700-1000 kg/m 3 .
  9. 9. Process according to any one of claims 1-8, wherein contacting the pyrolysis vapors with an aromatization catalyst in the smooth or bubbhng fluidized bed reactor is performed at aromatization temperature (T amm ) in the range of 300 to 650 °C, preferably 400 to 600 °C, more preferably 500 to 575 °C.
  10. 10. Process according to any one of claims 3-9 to the extent dependent on claim 3, wherein regenerating the aromatization catalyst is performed at a regeneration temperature (T re g) in the range of 500 °C or higher, preferably 600 °C or higher, more preferably 650 °C or higher, such as 700-800 °C.
  11. 11. Process according to any one of claims 1-9, wherein the gauge pressure upstream the aromatization reactor is 0.2 to 2.5 bar, preferably 0.5 to 2.0 bar, and wherein the pressure drop over the aromatization reactor is 0.05-1.5 bar.
  12. 12. Process according to any one of claims 1-11, wherein pyrolysis treatment is performed at pyrolysis temperature (T pyr ) in the range of 400 to 700 °C, preferably 425 to 650 °C.
  13. 13. Process according to any one of the preceding claims, wherein the residence time of the gas in the smooth or bubbling fluidized bed reactor is less than 2 minutes, preferably less than 1 minute, more preferably less than 30 seconds.
  14. 14. Process according to any one of the preceding claims, wherein the aromatization catalyst comprises one or more selected from the group consisting of ZSM-5, ZSM-11, ZSM-35, ZSM-23, ferrierite, zeolite beta, zeolite Y, zeolite X, mordenite, zeolite A, IM-5, SSZ-20, SSZ-55, MCM- 22, TNU-9, metal treated, exchanged or impregnated catalyst and combinations thereof.
  15. 15. Process according to claim 14, wherein the aromatization catalyst further comprises an amorphous binder.

Description

Title: Catalytic aromatization of pyrolysis vapors BACKGROUND OF THE INVENTION The invention is in the field of catalytic processes. In particular the present invention is directed to a thermo-catalytic pyrolysis process for the preparation of low molecular weight monocyclic aromatic compounds. Low molecular weight monocyclic aromatic compounds such as benzene, toluene, and xylenes (BTX) are important starting materials for high volume chemicals such as ethylbenzene, cumene, cyclohexane, adipic acid (from benzene), toluene diisocyanate, benzaldehyde and benzoic acid (from toluene) and terephthalic acid (from p -xylene). Currently, the above-described aromatic compounds are mainly produced via refinery processes of fossil resources, such as crude oil or coal. Common processes include steam cracking, steam reforming, catalytic cracking, such as fluid catalytic cracking, catalytic reforming, and coal tar distillation. Alternatively, biomass, waste or a combination thereof may be used for preparation or aromatics. Different kinds of biomass and/or waste can be used. Examples of waste that can be used include organic or biodegradable waste, and mixed plastic waste. Several routes have been proposed which can convert biomass or waste plastics materials via chemical synthesis and/or thermochemical conversion to aromatics. The thermal conversion of biomass and/or mixed plastic waste towards aromatics is a promising technique to reduce the plastic disposal and produce high-volume chemicals, especially for mixed and/or contaminated plastics that cannot be easily recycled. Whereas currently these streams are being incinerated and, in some cases, used for the conversion of plastics into alternative fuels, a conversion towards chemical building blocks for the chemical industry would significantly add value to these waste streams. A thermo-catalytic process for the preparation of low molecular weight monocyclic aromatic compounds is described in W02020204707. This document describes a two-step process, comprising the steps of subjecting a feed stream comprising plastic to a pyrolysis treatment producing pyrolysis vapors and the step of contacting the pyrolysis vapors with an aromatization catalyst in a catalytic conversion step to yield a conversion product comprising low molecular weight aromatic compounds. However, as mentioned in W02020204707, the product stream does not consist completely of aromatic compounds, and will typically also contain gaseous compounds such as carbon dioxide, carbon monoxide, hydrogen, water, low molecular weight alkanes, as well as by-products, such as olefins and oxygenates. In order to obtain low molecular weight monocyclic aromatic compounds without by-products and with higher purity, it is needed to fractionate and/or purify the low molecular weight monocyclic aromatic compounds. W02020204707 shows that the BTX yield, expressed in wt.% based on the organic fraction present in the plastics depends on feedstock and the temperature of the pyrolysis process. Catalytic processes for producing aromatics can be performed in fluidized bed reactors. A well-known example of a process creating aromatics in a fluidized bed reactor is fluid catalytic cracking (FCC). In FCC, not only cracking reactions take place, but also aromatization reactions play an important role. In FCC, riser reactors are typically used, more specifically Davison risers, in which the mixture of reactants/products and fluidized catalyst particles move upwards together, in a plug-flow manner. These fluidized conditions are often referred to as fast fluidization. After reaching the top of the riser, coke-laden catalyst particles are regenerated and fed as fresh catalyst to the bottom of the riser. In order to achieve these conditions, the flow rate of reactants is relatively high compared to the diameter of the reactor, resulting in a relatively short residence time of reactants/products in the catalyst bed. Because the reactants/products and catalyst particles move together, a downside of these fast fluidization conditions is that it is difficult to control the rate of catalyst regeneration independently of the space velocity in the reactor. Another downside of using fast fluidization and/or a riser reactor is that these are optimized for processes in which the catalyst particles deactivate fast and need instant regeneration, making them less suitable for processes in which the catalyst deactivates slower. Other downsides include the limited contact time between substrate and catalyst, plug-flow behavior, limited catalyst-substrate ratios, and the need for a tall construction. An object of the invention is to increase the yield of low molecular weight monocyclic aromatic compounds, such as BTX, and/or to reduce the amount of unwanted byproducts such as oxygenates in aromatization of pyrolysis vapors. Another object of the invention is to improve energy efficiency of thermo-catalytic processes for the preparation of low molec