Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 7, Issue 1, 2015

In this review paper, recent research and developments studies dealing with the bioconversion of bioresources and biowastes into biogas will be studied and discussed. Several kinds of natural feedstocks were analysed for their aptitude to produce gaseous biofuels such as woods, grasses, algae, agricultural residues, industrial by-products and household wastes. The related research studies revealed promising production yields including 400 L of methane (CH4) per Kg of volatile solids (VS) for Willow shoots, 270 L CH4/Kg VS for macro alga Ulva lactuca and 493 L CH4/Kg VS for paper wastes. Overall, the main objective is to present the research undertakings and findings in the scientific and industrial communities on biogas production procedure, its influencing factors and upgrading into biomethane.

Lead ion is a well-known divalent metal ion because of its harm to the human body, and fluorescent tracer technique has been proven to be the most appropriate means to detect lead ion in human body. Many fluorescent probes have been proposed, and some have been applied successfully in lead detection. This paper reviews recent patents and research articles focusing on the design strategy of lead probe based on the molecular structure.

Oily wastewater is waste originating from industries primarily engaged in refining crude oil and manufacturing fuels, lubricants and petrochemical intermediates. In this review, the characteristics and environmental impacts of oily wastewater were introduced. Methods for oily wastewater treatment were summarized based on recent literature and patents. Finally, this paper prospected the development trend of oily wastewater treatment technology.

The normal production of oil fields was seriously affected by the mineral scale formation, especially calcium deposition. This paper focused on the types, mechanisms and influencing factors of common scales oilfield scaling, especially carbonate scale and sulfate scale. Besides, some prediction models which were widely practiced in the oilfield to determine the scaling tendency of oilfield brine were described. The development and scale inhibition mechanisms of scale inhibitors which were used in oilfield were introduced and the scale removal and inhibition technology were reviewed. Furthermore, some patents of scale inhibitors and removal technology were commented.

Surface-modified activated carbon fibers (ACFs) with nitrogen-containing groups were prepared by the heat treatment of ACFs with urea, and characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetry (TG). The removal activity of the samples was also tested at an SO2 concentration of 22800 mg/Nm3. The results showed that the surface-modified ACFs significantly improved the SO2-removal ability compared to the unmodified ones. The amount of C=O and the nitrogen-containing groups on the surface of the N-modified ACFs increased, resulting in improved SO2-removal ability. The sample prepared with a urea concentration of 0.15 g/ml showed the best SO2-removal performance.

The solid fuel combustion in the thermal power plants, which use sulfur-rich fuels, poses the problem of sulfur dioxide removal from the waste gases. This problem is complicated by the fact, that it is required to purify huge amounts of gas with low SO2 concentration. The huge gas amounts need big size apparatuses, which is possible to be decreased if the absorption rate is maximal. The theoretical analysis of the methods and for purification of waste gases from S?2, using two-phase absorbent (CaCO3 suspension) shows, that the process is practically a physical absorption and the mass transfer resistances in the gas and liquid phases are 44% and 56%, respectively. In these conditions a new patent is proposed, where the process of optimization is realized in three zone columns, where the upper zone is a physical absorption in gasliquid drops system, the middle zone is a physical absorption in liquid-gas bubbles system and the chemical reaction takes place at the bottom of the column. The convection-diffusion type of models permits to create the average concentration models and give quantitative description of the absorption processes.

Sequencing batch reactor (SBR) is a type of activated sludge treatment, in which the aeration and clarifying step take place in a single reactor. There are several literatures and patents that have investigated the ability of SBR in wastewater treatment. In this study, the short-time effects of operative parameters, including influent COD, COD/N ratio, COD/P ratio, aeration time, settling time, temperature, and the memory of reactor on performance of a SBR in treating starchy wastewater were investigated. Fractional factorial design (FFD) approach was applied for the design of experiment. Fuzzy inference systems (FIS) with Mamdani's and Sugino's method were developed to simulate the effects of operative parameters. Accordingly, the ability of several structures of FIS was investigated. There was a significant difference between Mamdani's and Sugino's model with wtaver defuzzification. But the model accuracy of Sugino's with wtsum is very poor. Generally, the ability of Mamdani' model in response prediction is higher than Sugino's. The correlation coefficient index (R2) of the best FIS structure was 0.9774.