https://backend.orbit.dtu.dk/ws/files/190081841/BiogasUpgrade_Review.pdf

Biogas upgrading and utilization: Current status and perspectives

Flocculation as a low-cost method for harvesting microalgae for bulk biomass production.

Research studies on microalgae have increased in the last decades due to the wide range of applications associated to these photosynthetic microorganisms. Microalgae are an important source of oils and other biomolecules that can be used in the production of biofuels and high-valued products. However, the use of microalgae in these green processes is still not economically viable. One of the main costs associated to microalgal production is related to the harvesting process, as it usually accounts for about 20–30% of total cost. Therefore, this review focuses on the main harvesting processes applied to microalgae, presenting the main advantages and disadvantages of each method, to allow the selection of an appropriate procedure to effectively separate microalgal biomass from the culture medium. To reduce the associated costs, it is common to harvest microalgae in a two-step separation: (i) thickening procedures, in which microalgal slurry is concentrated to about 2–7% of total suspended solids; and (ii) dewatering procedures, which result in the concentration of microalgal slurry to 15–25% of total suspended solids. Selection of the adequate harvesting methods depends on the characteristics of the target microorganism and also on the type and value of the end product.

/pdf/harvesting-techniques-applied-to-microalgae-a-review-4te3owbtzq.pdf

Harvesting techniques applied to microalgae: A review

Constraints to commercialization of algal fuels.

Biogas is experiencing a period of rapid development and biogas upgrading is attracting increasing attention. Consequently, the market for biogas upgrading is facing significant challenges in terms of energy consumption and operating costs. Selection of upgrading technology is site-specific, case-sensitive and dependent on the biogas utilisation requirements and local circumstances. Therefore, matching the technology selected for use to specific requirements is significantly important. This paper systematically reviews the state-of-the-art of biogas cleaning and upgrading technologies, including product purity and impurities, methane recovery and loss, upgrading efficiency and the investment and operating costs. In addition, the potential utilisation of biogas and the corresponding requirements on gas quality are investigated in depth. Based on the results of comparisons between the technical features of upgrading technologies, the specific requirements for different gas utilizations and the relevant investment and operating costs, recommendations are made regarding appropriate technology.

Selection of appropriate biogas upgrading technology-a review of biogas cleaning, upgrading and utilisation

Biogas from anaerobic digestion and landfills consists primarily of CH 4 and CO 2 . Trace components that are often present in biogas are water vapor, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen. In order to transfer biogas into biomethane, two major steps are performed: (1) a cleaning process to remove the trace components and (2) an upgrading process to adjust the calorific value. Upgrading is generally performed in order to meet the standards for use as vehicle fuel or for injection in the natural gas grid. Different methods for biogas cleaning and upgrading are used. They differ in functioning, the necessary quality conditions of the incoming gas, the efficiency and their operational bottlenecks. Condensation methods (demisters, cyclone separators or moisture traps) and drying methods (adsorption or absorption) are used to remove water in combination with foam and dust. A number of techniques have been developed to remove H 2 S from biogas. Air dosing to the biogas and addition of iron chloride into the digester tank are two procedures that remove H 2 S during digestion. Techniques such as adsorption on iron oxide pellets and absorption in liquids remove H 2 S after digestion. Subsequently, trace components like siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen can require extra removal steps, if not sufficiently removed by other treatment steps. Finally, CH 4 must be separated from CO 2 using pressure swing adsorption, membrane separation, physical or chemical CO 2 -absorption.

Techniques for transformation of biogas to biomethane

Flue gas compounds and microalgae: (bio-)chemical interactions leading to biotechnological opportunities

Microalgal bacterial floc (MaB-floc) reactors have been suggested as a more sustainable secondary wastewater treatment We investigated whether MaB-flocs could be used as tertiary treatment Tertiary influent has a high inorganic/organic carbon ratio, depending on the efficiency of the secondary treatment In this study, the effect of this inorganic/organic carbon ratio on the MaB-flocs performance was determined, using three sequencing batch photobioreactors The MaB-flocs were fed with synthetic wastewater containing 84, 42, and 0 mg L−1 C-KHCO3 supplemented with 0, 42, 84 mg L−1 C-sucrose, respectively, representing inorganic versus organic carbon Bicarbonate significantly decreased the autotrophic index of the MaB-flocs and resulted in poorly settling flocs Moreover, sole bicarbonate addition led to a high pH of 95 and significant lower nitrogen removal efficiencies Sucrose without bicarbonate resulted in good settling MaB-flocs, high nitrogen removal efficiencies and neutral pH levels Despite the lower chlorophyll a content of the biomass and the lower in situ oxygen concentration, 92–96% of the soluble COD-sucrose was removed This study shows that the inorganic/organic carbon ratio of the wastewater is of major importance and that organic carbon is requisite to guarantee a good performance of the MaB-flocs for wastewater treatment Biotechnol Bioeng 2011; 108:549–558 © 2010 Wiley Periodicals, Inc

Microalgal bacterial floc properties are improved by a balanced inorganic/organic carbon ratio

Thermo-chemical pre-treatment to solubilize and improve anaerobic biodegradability of press mud

ANALYTISCHE CHEMIE This site isn`t the same as a solution manual you buy in a book store or download off the web. Our Over 40000 manuals and Ebooks is the reason why customers keep coming back. If you need a analytische chemie, you can download them in pdf format from our website. Basic file format that can be downloaded and read on numerous devices. You can revise this using your PC, MAC, tablet, eBook reader or smartphone.

Han Vervaeren

Papers

Techniques for transformation of biogas to biomethane

Flue gas compounds and microalgae: (bio-)chemical interactions leading to biotechnological opportunities

Microalgal bacterial floc properties are improved by a balanced inorganic/organic carbon ratio

Thermo-chemical pre-treatment to solubilize and improve anaerobic biodegradability of press mud

Analytische chemie I