A Pyrolysis Pilot Unit Integrated to a Circulating Fluidized Bed Boiler - Experiences from a Pilot Project

A novel integrated pyrolysis pilot plant has been built in Tampere, Finland by Metso, in co-operation with UPM, Fortum and VTT. A 7 tons of bio-oil per day (2 MWfuel input) fast pyrolysis unit has been integrated with Metso’s 4 MWth CFB pilot boiler. Test runs of bio-oil production have been carried out during 2009-2010. More than 80 tons of bio-oil has been produced and utilization tests have been started in district heating burner applications

Effects of ash removal by agitated aqueous washing and sedimentation on the physico-chemical characteristics and fast pyrolysis of trommel fines

A pre-treated trommel fines feedstock (DPT) with 35.1 wt% ash content and particle size range of 0.5–2 mm was processed through two (100% distilled water and 1% surfactant in distilled water) aqueous agitated washing and sedimentation procedures for ash reduction prior to fast pyrolysis in a bubbling fluidized bed reactor. The washing process led to more than 36% reduction in the ash/inorganic contents of the DPT feedstock and yielded about 78 wt% of organic-rich feedstocks denoted as WPT1 and WPT2. Characterisation and fast pyrolysis of all three feedstocks was carried out to evaluate the effect of the washing process on their physico-chemical characteristics and yields of fast pyrolysis products. Results showed that the ash reduction led to increase in the volatile matter contents of the washed feedstocks by 20%, while reducing nitrogen contents. In addition, fast pyrolysis of the feedstocks showed improved yield of liquid and gas products, with a dramatic reduction of reaction water, indicating that the ash removal reduced the catalytic effect of the ash on water formation during the fast pyrolysis process. The major organic compounds in the liquid products included phenols and furans from biogenic fraction of the feedstock as well as aromatic hydrocarbons such as those obtained from pyrolysis of plastics. More importantly, the overall energy yields from the fast pyrolysis process increased by over 35% after washing the feedstock, with washing with only distilled water alone giving the highest energy yield of 93%. Hence, coupling the water-washing ash reduction process with fast pyrolysis appeared to be a suitable technology for valorising feedstocks with high ash contents such as trommel fines for energy and chemicals

Microvawe pyrolysis of biomass: control of process parameters for high pyrolysis oil yields and enhanced oil quality

The oil yield and quality of pyrolysis oil from microwave heating of biomass was established by studying the behaviour of Larch in microwave processing. This is the first study in biomass pyrolysis to use a microwave processing technique and methodology that is fundamentally scalable, from which the basis of design for a continuous processing system can be derived to maximise oil yield and quality. It is shown systematically that sample size is a vital parameter that has been overlooked by previous work in this field. When sample size is controlled the liquid product yield is comparable to conventional pyrolysis, and can be achieved at an energy input of around 600 kWh/t. The quality of the liquid product is significantly improved compared to conventional pyrolysis processes, which results from the very rapid heating and quenching that can be achieved with microwave processing. The yields of Levoglucosan and phenolic compounds were found to be an order of magnitude higher in microwave pyrolysis when compared with conventional fast pyrolysis. Geometry is a key consideration for the development of a process at scale, and the opportunities and challenges for scale-up are discussed within this paper

Mono-, bi-, and tri-metallic Ni-based catalysts for the catalytic hydrotreatment of pyrolysis liquids

Catalytic hydrotreatment is a promising technology to convert pyrolysis liquids into intermediates with improved properties. Here, we report a catalyst screening study on the catalytic hydrotreatment of pyrolysis liquids using bi- and tri-metallic nickel-based catalysts in a batch autoclave (initial hydrogen pressure of 140 bar, 350 A degrees C, 4 h). The catalysts are characterized by a high nickel metal loading (41 to 57 wt%), promoted by Cu, Pd, Mo, and/or combination thereof, in a SiO2, SiO2-ZrO2, or SiO2-Al2O3 matrix. The hydrotreatment results were compared with a benchmark Ru/C catalyst. The results revealed that the monometallic Ni catalyst is the least active and that particularly the use of Mo as the promoter is favored when considering activity and product properties. For Mo promotion, a product oil with improved properties viz. the highest H/C molar ratio and the lowest coking tendency was obtained. A drawback when using Mo as the promoter is the relatively high methane yield, which is close to that for Ru/C. H-1, C-13-NMR, heteronuclear single quantum coherence (HSQC), and two-dimensional gas chromatography (GC x GC) of the product oils reveal that representative component classes of the sugar fraction of pyrolysis liquids like carbonyl compounds (aldehydes and ketones and carbohydrates) are converted to a large extent. The pyrolytic lignin fraction is less reactive, though some degree of hydrocracking is observed

Influence of moisture contents on the fast pyrolysis of trommel fines in a bubbling fluidized bed reactor

In this study, the effect of moisture contents [2.69 wt% (bone-dry), 5 wt% and 10 wt%] on product yields and process conversion efficiency during fast pyrolysis of a pre-treated trommel fines feedstock was investigated at 500 °C. Experiments were carried out using a 300 g h −1 bubbling fluidised bed rig. Yields of organic liquids ranged from 15.2 to 19.6 wt% of feedstock, which decreased with increasing moisture content. Hence, the bone-dry feedstock gave the maximum yield and consequently the highest process conversion efficiency of 43%. Increased moisture content also led to increase formation of unidentified gas products, indicating increased conversion of organic liquids. Due to the high ash content of the feedstocks, about 52 wt% solid residues, containing around 82% ash was recovered in the char pot in each case. Hence, to maximize oil yields during fast pyrolysis, trommel fines would require extensive drying to remove the original 46 wt% moisture as well as reducing the ash content considerably. XRF analysis of the ash in the feedstock and solid residues showed that the main elements present included Ca, Si, Fe, Pb, K, Cl and Al. Apart from the presence of Pb (which may be from the glass contents of the feedstock), the solid residues could be used for land reclamation or co-incinerated at cement kilns for cement manufacture

Energy recovery by fast pyrolysis of pre-treated trommel fines derived from a UK-based MSW material recycling facility

In this experimental study, a physically pre-treated trommel fines feedstock, containing 44 wt% non-volatiles (ash and fixed carbon) and 56 wt% volatile matter (dry basis), was subjected to fast pyrolysis to recover energy from its organic load, using a 300 g h−1 bubbling fluidized bed (BFB) fast pyrolysis rig. A physical pre-treatment method (including crushing, grinding and sieving) was used to prepare a 0.5–2 mm sized trommel fines feedstock to make it suitable for fast pyrolysis in the BFB reactor. Experimental results from the fast pyrolysis process showed that the highest yield of organic liquid was obtained at around a temperature of 500 °C. However, both char and gas yields increased dramatically at temperatures above 500 °C, as a result of enhanced cracking of organic vapours, which reduced the yield of liquid products. Overall, energy recovery from the pyrolysis products (liquid and gas products as well as char pot residues) ranged from 63 to 70%, generally increasing with temperature. A large proportion of the high ash content (36 wt%) of the feedstock was found in the char pot (>62%), while smaller proportions were found in the reactor bed and some liquid products. The char pot ash residues composed mostly of non-hazardous earth materials and may be applied in bulk construction materials e.g. cement manufacture. Although, there was no problem with the pyrolysis rig during 1 h of operation, longer periods of operation would require periodic removal of accumulated solid residues and/or char pot modification to ensure continuous rig operation and process safety