Hydrolysis
| Technology | |
| |
| Technology details | |
| Name: | Hydrolysis |
| Category: | Pre-processing |
| Feedstock: | Lignocellulosic biomass |
| Product: | Sugars and organic acids |
Hydrolysis (/haɪˈdrɒlɪsɪs/; from Ancient Greek hydro- 'water', and lysis 'to unbind') is a chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions that use water as the reagent.[1] In lignocellulosic biomass, the cellulose and hemicellulose breaks down into individual sugars. Hemicellulose is easier to hydrolyse than cellulose.[2] The result of hydrolysing hemicellulose and cellulose are sugars (glucose, mannose, galactose, (C6) and xylose, arabinose (C5)) and organic acids (formic acid and acetic acid).[3]
Feedstock
Origin and composition
Hydrolysis can be performed as a pretreatment on any biowaste with a high lignocellulose content. Lignocellulose is typically the nonedible part of a plant, composed of a complex of cellulose, hemi-cellulose and lignin. In order to make the cellulose available for further processing, in the form of its monomeric sugars, they can be hydrolysed. Suitable feedstocks include grasses, straw, leaves, stems, shells, manure, paper waste, and others. The ratio between cellulose, hemi-cellulose and lignin varies wildly depending on the specific feedstock.[4]
Pre-treatment
Currently no pre-treatment has been identified.
Process and technologies
Acid
Acid hydrolysis is a hydrolysis process in which a protic acid is used to catalyze the hydrolysis reaction. A strong acid, such as formic, hydrochloric, nitric, phosphoric, or sulphuric acid can be used in concentrated or diluted form. Concentrated acid (10-30 %) can penetrate the lignin structure and break down the cellulose and hemicellulose to individual sugars at low temperature and with high yield. Downsides are the high acid consumption and high corrosion potential. These downsides are circumvented with the use of diluted acid (2-5 %). However, in the latter case, higher temperature is required, which can lead to side product formation such as furfural and 5-hydroxymethyl-furfural.[4]
Alkali
Alkaline hydrolysis refers to hydrolysis reactions using hydroxide, commonly from sodium hydroxide or calcium hydroxide. The hydroxide breaks down the lignin bonds to make the cellulose more accessible. The reaction proceeds at lower temperature and pressure and residual alkali can be recycled. However, the pretreatment does result in irrecoverable salts in the product.[5]
Salt
Hydrolysis can be further improved by the addition of salts, such as metal salts or sulphite salts.
Metals salts
Acid hydrolysis can be stimulated by the addition of metal chlorides. Metals such as aluminium, calcium, copper, iron, and zinc can be used to increase the sugar yield.[6]
Sulphite salt
Similar to sulphite pulping, sulphites can be added to acid hydrolysis to aid in lignin removal.
Solvent
Solvents can be added to improve the hydrolysis process. This is similar to organosolv pulping, but without the delignification as goal.[7]
Organosolv
In an organosolv hydrolysis organic solvents are added to the process, usually performed at high temperatures (100-250 °C). This can be combined with a catalyst such as HCl or H2SO4.[7] For example, in acid-acetone pre-treatment biowaste is treated with an acid such as phophoric acid and then mixed with pre-cooled acetone.[6]
Ionic Liquids
Ionic liquids are solvents that can be used for biomass pretreatment, fractionation, and dissolution. During ionic liquid pretreatment, a cellulose-rich fraction can be generated through the degradation and removal of a large portion of lignin and hemicellulose [8]
Subcritical water
Product
Hydrolysis is generally performed on cellulose and hemi-cellulose, which results in different sugars: glucose, mannose, and galactose as C6 sugars, and xylose and arabinose asC5 sugars. Next to these, organic acids are often formed in formic acid and acetic acid.
Post-treatment
Currently no post-treatment has been identified.
Technology providers
| Company name | Country | Technology category | Technology name | TRL | Capacity [kg/h] | Catalyst loading [wt %] | pH | Pressure [bar] | Reactor | Residence time [h] | Temperature [°C] | Feedstock: Food waste | Feedstock: Garden & park waste |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Company 1 | [Country HQ location] | [Technology category (if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● | ||||||
| Company 2 | [Country HQ location] | [(if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● |
NextChem
Valmet Oyj
| General information | |||
| Company: | Valmet Oyj |
| |
| Country: | Finland | ||
| Contact: | |||
| Webpage: | https://www.valmet.com/ | ||
| Technology and process details | |||
| Technology name: | BioTrac | Technology category: | Pre-processing (Chemical processes and technologies) |
| TRL: | 9 | Capacity: | biomass feed up to 800 tonne/day kg·h-1 |
| Agitator: | Atmosphere: | ||
| Catalyst: | Acidic conditions | Controlled parameters: | |
| Temperature: | High °C | Catalyst: | Acidic conditions |
| Processable volume: | L | Reactor: | Horizontal tube reactor |
| Reactor material: | Safety restrictions: | ||
| Temperature: | High °C | Other: | |
| Feedstock and product details | |||
| Feedstock: | All lignocellulosic biomass, including wood and forestry residues, wheat straw, corn stover and bagasse | Product: | |
Open access pilot and demo facility providers
Patents
Currently no patents have been identified.
References
- ↑ Wikipedia, 2002: Hydrolysis 2002, Last access 2021. https://en.wikipedia.org/wiki/Hydrolysis
- ↑ P. Lenihan, A. Orozco, E. O’Neill, M.N.M. Ahmad, D.W. Rooney, G.M. Walker, 2010-01-15: Dilute acid hydrolysis of lignocellulosic biomass. Chemical Engineering Journal, Vol. 156, (2), 395–403. doi: https://doi.org/10.1016/j.cej.2009.10.061
- ↑ Katarzyna Świątek, Stephanie Gaag, Andreas Klier, Andrea Kruse, Jörg Sauer, David Steinbach, 2020-04-17: Acid Hydrolysis of Lignocellulosic Biomass: Sugars and Furfurals Formation. Catalysts, Vol. 10, (4), 437. doi: https://doi.org/10.3390/catal10040437
- ↑ a b Alessandra Verardi, Isabella De Bari, Emanuele Ricca and Vincenza Calabrò, 2012: Hydrolysis of Lignocellulosic Biomass: Current Status of Processes and Technologies and Future Perspectives. Bioethanol. Marco Aurelio Pinheiro Lima and Alexandra Pardo Policastro Natalense (Ed.). IntechOpen, {{{place}}}.
- ↑ S. Niju, M. Swathika, M. Balajii, 2020-01-01: Pretreatment of lignocellulosic sugarcane leaves and tops for bioethanol production. Lignocellulosic Biomass to Liquid Biofuels, Vol. , 301–324. doi: https://doi.org/10.1016/B978-0-12-815936-1.00010-1
- ↑ a b Amit K. Jaiswal, Rajeev Ravindran, 2016-01-01: A comprehensive review on pre-treatment strategy for lignocellulosic food industry waste: Challenges and opportunities. Bioresource Technology, Vol. 199, 92–102. doi: https://doi.org/10.1016/j.biortech.2015.07.106
- ↑ a b Valery B. Agbor, Nazim Cicek, Richard Sparling, Alex Berlin, David B. Levin, 2011-11: Biomass pretreatment: Fundamentals toward application. Biotechnology Advances, Vol. 29, (6), 675–685. doi: https://doi.org/10.1016/j.biotechadv.2011.05.005
- ↑ Moyer, P., Kim, K., Abdoulmoumine, N. et al., 2018: Structural changes in lignocellulosic biomass during activation with ionic liquids comprising 3-methylimidazolium cations and carboxylate anions 27/09/2018, Last access 06/12/2021. https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-018-1263-0