A comparison of product yields and inorganic content in process streams following thermal hydrolysis and hydrothermal processing of microalgae, manure and digestate

Abstract

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Thermal hydrolysis and hydrothermal processing have shown promise for converting biomass 10 into higher energy density fuels. Both approaches can facilitate the extraction of inorganics in 11 to the aqueous process waters. This study compares the behaviour of microalgae, digestate, 12 swine and chicken manure by thermal hydrolysis and hydrothermal processing at increasing 13 process severity. Thermal hydrolysis was performed at 170 °C, hydrothermal carbonization 14 (HTC) was performed at 250 °C, hydrothermal liquefaction (HTL) was performed at 350 °C 15 and supercritical water gasification (SCWG) was performed at 500 °C in a batch reactor. The 16 level of nitrogen, phosphorus and potassium in the product streams was measured for each 17 feedstock. Nitrogen is present in the aqueous phase as organic-N and NH3-N. The proportion 18 of organic N increases the lower the temperature. The extraction of phosphorus is strongly 19 linked to the presence of inorganics such as Ca, Mg and Fe in the starting feedstock. 20 A comparison of product yields and inorganic content in process streamsMicroalgae and chicken manure release phosphorus more easily than the other feedstocks. 21Keywords: hydrothermal processing, NPK, manure, microalgae, digestate 22 23 Introduction 24Hydrothermal processing of biomass can be utilised as either a pre-treatment or for energy 25 densification. Thermal hydrolysis is often used prior to anaerobic digestion at temperatures in 26 the range 160-170 o C resulting in enhanced biogas yields (Mendez et al., 2015). 27Hydrothermal carbonisation (HTC) is operated at 180-250 °C and pressure between 2-10 28MPa, and produces a carbon-rich bio-coal (Mumme et al., 2011). Hydrothermal liquefaction 29 (HTL) is operated at 280-370 °C and pressures ranging from 10-25 MPa and produces a 30 synthetic bio-crude (Biller et al., 2012). Supercritical water gasification (SCWG) is operated 1 at temperatures above 450 °C and pressure above the critical point of water (22 MPa) 2 producing a syngas containing H2, CO2 and CH4 (Toor et al., 2011). There is a growing 3 interest in the recovery of nutrients from wet wastes such as manures and bio-solids and 4 hydrothermal processing has been proposed to facilitate...

Techno-economic Assessment of Integrated Hydrothermal Liquefaction and Combined Heat and Power Production from Lignocellulose Residues

“…All pre-specified compounds were present in the organic yields with only 10 compounds reporting concentrations below 0.01 wt.%. It is worth to mention that nitrogen partitioned almost completely into inorganic form (simulated as ammonia), while sulphur remained attached in hetero form (simulated as 4-Isopropylthiophenol), similar to reports in [53]. Figure 6.…”

The BioSCWG Project: Understanding the Trade-Offs in the Process and Thermal Design of Hydrogen and Synthetic Natural Gas Production

“…It is worth noting that the organic structure, solid-to-water ratio, residence time, pressure, catalysis and process units' mechanical configurations also influence the specific yields of each product as has been reported [4][5][6]9,11,[13][14][15][16]. However, such information available in literature is diverse and fragmented, and temperature levels remain the governing processing parameter that identify the product phase distribution.…”

“…From a system design perspective, hydrothermal treatment attempts to exploit the properties near-to the critical point of the algal water substrate for extraction and recycling of nitrogen and phosphorus nutrients, necessary for cultivation. Ekpo et al [13] showed that up to 90% of nitrogen was recovered in the aqueous phase at 350 • C and more than 97% at 500 • C, with only less than 10% of nitrogen detected in hetero form. Elliot et al [15] claimed that 50% of the nitrogen demand for cultivation purposes could be recovered by the aqueous recycling.…”

“…Knez et al [10] classified hydrothermal treatment on the basis of the selected processing temperature and as a result the predominant yield nature, a similar approach has been adapted in other works as well [4,7,[11][12][13]. It is worth noting that the organic structure, solid-to-water ratio, residence time, pressure, catalysis and process units' mechanical configurations also influence the specific yields of each product as has been reported [4][5][6]9,11,[13][14][15][16].…”

Temperature influence on the fast pyrolysis of manure samples: char, bio-oil and gases production

“…However, these traditional uses have to be changed due to land limitations and the strict regulations [5]. The number of studies about the use of LSM as biomass to produce energy or other added-value products by anaerobic digestion of thermochemical processes has increased in recent years [6][7][8][9]. There are many different technologies which have been applied for biomass utilization.…”