Zoekresultaten

Process for the preparation of low molecular weight aromatics (btx) and biofuels from biomass

The present invention relates to a novel process for the preparation of low molecular weight aromatic compounds such as benzene, toluene, and xylenes (BTX) from plastics. Provided is a thermo-catalytic pyrolysis process for the preparation of aromatic compounds from a feed stream comprising plastic, comprising the steps of: a) subjecting a feed stream comprising a plastic to a pyrolysis treatment at a pyrolysis temperature in the range of 600-1000°C to produce pyrolysis vapors; b) optionally cooling the pyrolysis vapors to a temperature that is below the pyrolysis temperature; c) contacting the vaporous phase with an aromatization catalyst at an aromatization temperature in the range of 450 - 700 °C, which aromatization temperature is at least 50°C lower than the pyrolysis temperature, in a catalytic conversion step to yield a conversion product comprising aromatic compounds; and d) optionally recovering the aromatic compounds from the conversion product.

Enhanced Bio-BTX Formation by Catalytic Pyrolysis of Glycerol with In Situ Produced Toluene as the Cofeed

The catalytic coconversion of glycerol and toluene (93/7 wt %) over a technical H-ZSM-5/Al2O3 (60-40 wt %) catalyst was studied, aiming for enhanced production of biobased benzene, toluene, and xylenes (bio-BTX). When using glycerol/toluene cofeed with a mass ratio of 93/7 wt %, a peak BTX carbon yield of 29.7 ± 1.1 C.% (at time on stream (TOS) of 1.5-2.5 h), and an overall BTX carbon yield of 28.7 C.% (during TOS of 8.5 h) were obtained, which are considerably higher than those (19.1 ± 0.4 C.% and 11.0 C.%) for glycerol alone. Synergetic effects when cofeeding toluene on the peak and overall BTX carbon yields were observed and quantified, showing a relative increase of 3.1% and 30.0% for the peak and overall BTX carbon yield (based on the feedstock). These findings indicate that the strategy of cofeeding in situ produced toluene for the conversion of glycerol to aromatics has potential to increase BTX yields. In addition, BTX production on the catalyst (based on the fresh catalyst during the first run for TOS of 8.5 h and without regeneration) is significantly improved to 0.547 ton ton-1catalyst (excluding the 76% of toluene product that is 0.595 ton ton-1catalyst for the recycle in the cofeed) for glycerol/toluene cofeed, which was 0.426 ton ton-1catalyst for glycerol alone. In particular, this self-sufficient toluene product recycling strategy is advantageous for the production and selectivity (relative increase of 84.4% and 43.5% during TOS of 8.5 h) of biobased xylenes.

Development Midstream processing of Flax-fiber

Stricter environmental policies, increased energy prices and depletion of resources are forcing industries to look for bio-based and low carbon footprint products. For industries, flax is interesting resource since it is light, strong, environmental friendly and renewable. From flax plant to fiber products involves biochemical and mechanical processes. Moreover, production and processing costs have to compete with other products, like petroleum based materials. This research focusses on sustainable process improvement from flax plant to fiber production. Flax retting is a biological process at which mainly pectin is removed. Without retting, the desired fibre remains attached to the wooden core of the flax stem. As a result, the flax fibres cannot be gained, or have a lows quality. After retting, the fibers are released from the wooden core. Furthermore, machines have been introduced in the flax production process, but the best quality fibers are still produced manually. Due to the high labor intensity the process is too expensive and the process needs to be economical optimized. Since the retting process determines all other downstream processes, retting is the first step to focus on. Lab-scale experiments were performed to investigate the retting process. Factors that were researched were low cost processing conditions like, temperature, pH, dew retting and water retting. The retting rate was low, around three weeks for complete retting. The best retting conditions were at 20°C with water and any addition of chemicals. The process could be shortened to two weeks by recycling the water phase. In a scale-up experiment, a rotating drum was used at the optimal conditions from the lab-experiment (20°C and water). First the flax did not mix with the water content in the rotating drum. The flax was too rigid and did not tumble. Therefore, bundles of flax plants were used. The inner core of the bundle seemed to be protected and the retting rate was less compared to the flax on the surface of the flax bundle. This implies that mechanical impact increased retting in the rotating drum, however heterogeneous retting should be avoided. To overcome the heterogeneous retting problem, a water column was used to improve heterogeneous retting. Retting was performed in a water column and mixing was accomplished by bubbling air. As a result of the mixing, the flax bundle was retted homogenously. And after drying, it was possible to separate the fibers from the wooden flax core. Retting with a bubble column can overcome this problem and seems to be a usable retting process step. Water samples of the lab-scale experiments, the rotating drum and the bubble column showed a chemical oxygen demand (COD) content up to 4 g/L. Overall, 1 kg Flax resulted in 40 g COD. This indicates the possibility to produce biogas that can be used for generating heat and electricity, to make the process sustainable. Around 50% of the weight consists of wooden shives. The shives can be used for pyrolysis and it was possible to produce around 30% coal and 20% oil. These compounds can be used as building blocks, but also to generate heat and electricity. Heat and electricity can be used for the flax processing. Shives were only dried for 1 day at 105°C and slow pyrolysis was used. This indicates that a higher yield can be expected at fast pyrolysis. Overall, the reported implicates that quality fiber production from flax plant can be a feasible, sustainable and a renewable production process. Feasibility of the process can be obtained by, (1) retting at low-cost process conditions of 20°C and using water without any addition of chemicals, (2) with increased flax retting rate by recycling water, (3) with increased flax retting rate by introducing mixing forces, and the ability to lower the energy consumption of the overall process, (4) producing biogas from the COD with anaerobic digestion and (5) producing pyrolysis oil and pyrolysis c

An improved catalytic pyrolysis concept for renewable aromatics from biomass involving a recycling strategy for co-produced polycyclic aromatic hydrocarbons†

Synthesis of Bio-aromatics from Black Liquors Using Catalytic Pyrolysis

Bio-aromatics (benzene, toluene, xylenes, BTX) were prepared by the catalytic pyrolysis of six different black liquors using both in situ and ex situ approaches. A wide range of catalysts was screened and conditions were optimized in microscale reactors. Up to 7 wt % of BTX, based on the organic fraction of the black liquors, was obtained for both the in situ and ex situ pyrolysis ( T = 500-600 °C) using a Ga-modified H-ZSM-5 catalyst. The in situ catalytic pyrolysis of black liquors from hardwood paper mills afforded slightly higher yields of aromatics/BTX than softwood black liquors, a trend that could be confirmed by the results obtained in the ex situ catalytic pyrolysis. An almost full deoxygenation of the lignin and carbohydrate fraction was achieved and both organic fractions were converted to a broad range of (substituted) aromatics. The zeolite catalyst used was remarkably stable and even after 100 experiments in batch mode with intermittent oxidative catalyst regeneration, the yields and selectivity toward BTX remained similar. The ex situ pyrolysis of black liquor has potential for large-scale implementation in a paper mill without disturbing the paper production process.

Low Molecular Weight Biobased Aromatics from Pyrolysis Liquids Using Zeolites: Yield Improvements by Using Pyrolysis Oil Fractions

Pyrolysis liquids from lignocellulosic biomass have the potential to be used as a feed for aromatics such as benzene, toluene, and xylenes (BTX) using catalytic upgrading with zeolites. We here report an experimental study on the conversion of various pyrolysis oil fractions to determine the most suitable one for BTX synthesis. For this purpose, the pyrolysis liquid was fractionated using several extraction/distillation steps to give four fractions with different chemical compositions. The fractions were analyzed in detail using nuclear magnetic resonance spectroscopy, elemental analysis, gas chromatography-mass spectroscopy, thermogravimetric analysis, Karl-Fischer titration, and gel permeation chromatography. Catalytic pyrolysis experiments were carried out using a tandem microreactor with H-ZSM-5 (23) as the catalyst. The highest BTX yield of 24% (on a carbon and dry basis) was obtained using the fractions enriched in phenolics, whereas all others gave far lower yields (4.4-9%, on a carbon and dry basis). Correlations were established between the chemical composition of the feed fraction and the BTX yield. These findings support the concept of a pyrolysis biorefinery, where the pyrolysis liquid is separated into well-defined fractions before further dedicated catalytic conversions to biobased chemicals and biofuels using tailored catalysts.