Bio-chemical conversion

Nearly all biomass is eventually decomposed naturally through biological processes. Some of these processes can be harnessed to produce fuels. 

Sugar can be converted to ethanol based on micro-organisms. Because starch and even celluloses can be converted more or less easily into sugar, such biomass streams are also a potential resource for the production of bioethanol in addition to naturally sugar-containing crops like sugar cane and sugar beet (see Chapters 8 and 9.3). 

Material Yield of biogas in m mio organic dry matter Material Yield of biogas in m -mto organic dry matter 

Organic waste from 170-220 Food residues 81F120 

Waste fat 1040 Waste water from brewing industries 500 

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Although there is no commonly accepted definition of a membrane reactor (MR), the term is usually applied to operations where the unique abilities of membranes to organize, compartmentalize, and/or separate are exploited to perform a (bio)chemical conversion under conditions that are not feasible in the absence of a membrane. In every MR, the membrane separation and the (bio)catalytic conversion are thus combined in such a way that the synergies in the integrated setup entail enhanced processing and improved economics in terms of separation, selectivity, or yield, compared to a traditional configuration with reactor and separation separated in time and space. When the membrane itself carries the catalytic functions, it is mostly referred to as a reactive membrane. ... 

Recently, there has been a growing interest in the use of monohthic structures for (bio)chemical conversion and adsorption processes. A very versatile type of monolith is based on carbon. The combined properties of carbon and monolithic structures create a support with great potential. In this chapter we describe recent developments in the field of carbon-based monolithic structures with respect to preparation, support properties, and application in catalytic processes. Furthermore, two examples are used to demonstrate the approach and possible pitfalls when using carbon (coated) monoliths in catalysis. 

The length of time for which a substance persists in the environment is often stated in the form of a half-life of degradation. This is the time required for an initial concentration to be reduced by half. Strictly speaking, it is only possible to define of a half-life if degradation follows first order kinetics. This is the case if the speed of degradation is proportional to the current concentration of the substance. Since at least one reaction partner is necessary for the (bio)chemical conversion of a substance, this condition can only be fulfilled if an excess of such a reaction partner is present. This is usually the case with water and oxygen in suitable environmental media, which means that the reaction does in fact follow first order kinetics. 

Bio-chemical conversion two-culture-system for the production of substrates for biogas production, cultivation of input products for the ethanol production. 

Development of novel synthetic routes for efficient conversion of biomass derived raw materials with high performance, stability and selectivity, by integrating bio-, chemical and catalytic processes. Synthetic pathways in which the complexity needed in a target molecule is already preformed in the biomolecule are especially favorable. 

Any (bio)chemical reaction is accompanied by energy conversion, most often in the form of heat production, the amount of heat produced being proportional to that of substance converted. Therefore, heat is a highly nonspecific expression of a (bio)chemical reaction but can be used as indicative for a given substance when this is selectively converted (e.g. by effect of a catalyst, particularly an enzyme). This section discusses three types of sensors based on the use of as many types of devices for measurement of the heat involved in a biochemical reaction, namely fibre optics, polymer films and thermistors. 

Besides the heavy chemical industry, where catalysis is a dominant feature of most conversion processes, enzyme catalysis is a critical component of bio-chemical processes. All that was said about mechanisms of catalytic reactions applies to enzyme catalysis. As can be expected, there are additional factors in enzyme catalysis that complicate matters. Many enzymatic reactions depend on factors such as pH, ionic strength, co-catalysts and so on that do not normally play a role in conventional heterogeneous catalysis. Despite this, the understanding of mechanisms in enzyme catalysis has outpaced that in heterogeneous catalysis and can now serve as a guide to the search for heterogeneous reaction mechanisms. 

Both biomethane production paths complement one another in an ideal way. While the thermo-chemical route focuses on solid biofuels e.g. wood, straw) the bio-chemical route uses wet biomass e.g. animal manure, maize silage). The latter will be realized with plant capacities in the one-digit thermal MW-scale and the former in the two- to three-digit MW-scale. The provided product is basically similar and can be used together with natural gas in any mixture. The erection of the biogas and Bio-SNG conversion plants can be planned directly at the established gas grid. 

The most common bio-aliphatic polyesters are poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), polyfe-caprolactone) (PCL), and poly(3-hydroxybutyrate) (PHB). While PLA, PLGA, and PHB are bio-based, PCL is obtained from the chemical conversion of crude oil. But all of them are biodegradable and biocompatible. Thus, they attract increasing attention in biomedical applications. However, the biopolyesters present poor thermal stability with respect of traditional oil-based polyesters. 

Henrich, E. Raffelt, K. Stahl, R. Weirich, F., Clean syngas from bio-oil/char-slurries. In Science in Thermal and Chemical Biomass Conversion, Bridgwater, A. V. Boocock, D. G. B., Eds., CPL press, Victoria, 2004, pp. 1565-1579. 

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