A review of the production technologies of bioethanol, an eco-friendly automotive fuel, from non-edible and renewable lignocellulosic bioresources and agricultural wastes is presented, based on the recently developed patents and research works. The different technologies such as ammonia fibre/freeze explosion, organosolv process, ozonolysis, acid and/or enzymatic hydrolysis, simultaneous or separate saccharification and fermentation along with consolidated bioprocessing are described along with the major research trends to optimize their efficiencies of producing fuel ethanol from lignocellulosic biomass. Biological, thermo-chemical and enzymatic engineering aspects will be critically reviewed regarding the lignocellulosic biomaterials conversion into renewable and pollution-free fuel, bioethanol.
Throughout the past ten years global society has more of a vested interest in the research and development of sustainable energy sources. Carbon dioxide fixation and collection of biodiesel oils through the utilization of microalgae can not only possibly help the reduction of flue gas emissions, but also have the potential to provide clean energy. Microalgae growth is affected by numerous factors influencing the yield and quality of biodiesel; such as agitation and mixing, light source, sedimentation, and other growth inhibiting or inducing factors. Specifically, photobioreactor design is a major area of concern, and thus different types of reactors are examined along with innovative patents attempting to overcome such obstacles of algae growth. These patents along with current research give an overall look at the progression of this field of study and the areas some researchers and scientists are heading toward in the future. This review article encompasses an overview and background of the whole microalgae growth and harvesting process along with reviewing many of the photobioreactors designs now being utilized in present research.
Pressure driven membrane processes are widely used in various separation related applications ranging from production of drinking water from sea water and brackish water to separation of valuables from product streams or effluent management in industries. Research works are going on world over to develop novel membrane materials with superior performance having high selectivity, high throughput and better life. The research works cover all important fields of membrane separation including development of novel materials for membranes, development of new processes of making membranes and modification of membranes to achieve improved performances. In reverse osmosis (RO), to make membranes with better solute rejection and superior flux novel techniques are adopted like modification of reaction mixtures by added chemicals like multi functionary tertiary amine alcohol or polar compounds like triethylene glycol octyl methyl ether which eventually modifies the resulting membranes. For fouling resistant RO membranes methods have been developed where polymers resemble like brushes so that fouling is minimized. Membranes have been developed which are resistant to degradation due to oxidation. In nanofiltration (NF), in addition to development of fouling resistant membranes, new techniques have been developed for solvent resistant membranes. For microfiltration and ultrafiltration techniques have been developed for fouling resistant membranes by a novel layered coating of membranes. The present review describes some of the important works on membrane development, especially discovery of new polymeric membrane materials covering these aspects, disclosed in the patents in recent times.
Reactive distillation is being increasingly viewed as a highly promising alternative in the improvement of processes, exploiting the positive synergistic effects of integrating reaction and separation. Today, the technology has widened the scope of application beyond exothermic reactions and equilibrium limited reactions. This has led to intensive research about applications, synthesis/ design of operation and design of column devices of reactive distillation in academia as well as in industry. This article focuses specifically on reviewing and discussing patents for the application of heterogeneous catalytic distillation systems.
In the last two decades, supercritical fluid drying or supercritical drying has attracted growing interests for its increasing applications in various fields. The purpose of this review is to summarize the recent patents in literature about supercritical drying with the introduction of different technologies and applications. To avoid confusion, supercritical drying is conveniently classified into five types, namely, they are supercritical organic solvent drying, supercritical gas drying, supercritical mixture solvent drying, supercritical gas extraction-drying, and supercritical fluid-assisted spray drying of aqueous solution for preparing fine particles. The former four techniques are classified according to the applied supercritical solvent, and can be particularly applied to drying porous materials. Supercritical fluid-assisted spray drying uses supercritical fluid as the atomizing gas and the carrier of moisture. The applications of supercritical drying in the production of aerogel and other porous materials, drying of pharmaceuticals and foods, and the production of microelectromechanical systems are summarized.