Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 10, Issue 2, 2017

Greenhouse gas emissions contribute immensely to global warming. One of the major constituents of greenhouse gas emissions is carbon dioxide (CO2). It is highly essential to reduce its emissions into the atmosphere. One of the ways to reduce its emissions is to capture and store it. Currently, monoethanolamine (MEA) is used to separate out CO2 from the flue gas. This process is expensive and it comes with a significant energy penalty for the power plants. As an alternative, calcium looping process was proposed. This process makes use of the reversible reaction between calcium oxide (CaO) and CO2 to give calcium carbonate (CaCO3). When separation is desired flue gas is sent through the sorbent (CaO), then it is sent through the regenerator which provides a pure stream of CO2 for carbon capture. This process allows attainment of high carbon capture rates. Furthermore, it comes with a lower energy penalty for power plants. In addition, it can be easily retrofitted to power plants. At present, no known industrial implementations of calcium looping exist. The research thus far is restrained to pilot plant stage. Calcium looping has been proposed recently and a lot of rapid developments are taking place. Bigger pilot-plants are designed for testing newer models developed from the recent experimental findings. Also, newer sorbents are being tested which give an improved performance. In this paper, we will review the current status of research on calcium looping. Our objective is to give a general overview of recent developments in this field. We have addressed its feasibility on industrial scale. We discuss the different models used to describe this process, optimization of different parameters which affect the process, problems associated with it and modifications to this process to make it more efficient and improve it. We also review the economics of calcium looping process in comparison with the conventional process. Furthermore, we have also discussed the potential of wide variety of applications in which calcium looping cycles can be used.

Pour point depressant added in the process of waxy crude oil transmission can effectively improve the fluidity. This is one of the effective ways to achieve crude oil transmission at room temperature. This paper expound the development of pour point depressant, wax crystallization process, classification of pour point depressant, mechanism of the pour point depressant, conditions of limiting the effect of crude oil pour point and application status.

This work briefly describes the composition of the lubricating oiland the types of flow improvers, pointing out the advantages of nano-hybrid pour point depressant and some common types of nano-hybrid pour point depressant. The author summarizes the experimental instruments and methods which were commonly used in the study of the mechanism of pour point, pointing out the factors that affect its effect on the lubricating oil. The mechanism of the action of the pour point depressant and the viscosity index improvers in lubricating oil are described. The author describes the preparation, design and application of the environment-friendly pour point depressant, which helps researchers to study the lubricating oil pour point depressants.

Background and Objective: For the alkyl and aryl derivatives of five-membered nitrogen-containing heterocyclic compounds a good correlation has been found between the experimental values of the enthalpy of formation of these compounds in the condensed state and the values calculated using semi-empirical quantum-chemical method PM3. Conclusion: A comparison of the proposed method with that of additive deposits and QSPR was made. Linear regression equation derived on the basis of correlation was used to predict the enthalpy of formation of compounds under consideration.

Objective: Biodiesel production from microalgae is one of the most suitable and promising sources of clean energy. Various environmental factors affect the microalgae growth. Current study investigates two environmental factors namely temperature and light intensity which affect microalgae growth (by Response surface methodology), and suggests properties of the produced biodiesel through two different methods under optimal cultivation conditions such as temperature and light intensity. Results: The results showed that temperature has the most effect on microalgae growth, so that the optimal temperature and light intensity were obtained to be 30°C and 10 Klux, respectively. Under foresaid conditions, biomass concentration, maximum specific growth rate and biomass productivity were measured to be as high as 1.88 g/L, 0.1180 l/day and 0.1078 g/L/day, respectively. Saturated fatty acids composition in this microalgae include Myristic acid (C14:0 , 41.13%), Palmitic acid (C16:0 , 10.44%) and Stearic acid (C18:0 , 0.82%). Conclusion: The Cetane number of the produced biodiesel was measured to be 64.4, which shows high capability of the microalgae in biodiesel production.

Background: Solid suspension in liquids is an important unit operation generally encountered in the process industry. In the present work solid−liquid suspensions are explored in an agitated vessel with different liquids using two radial impellers namely Rushton turbine and straight blade; two axial impellers namely pitched blade turbine and A320. The critical impeller speed (Njs) at which all solid particles get suspended and the relevant power requirements (Pjs) are evaluated. The effect liquid viscosity on these two parameters is investigated. Conclusion: Results show that critical impeller speed and power consumption decreases as liquid viscosity increases. The critical impeller speed was found to be highest for straight blade impeller and lowest for pitched blade turbine. A320 impeller showed strong dependence of viscosity on critical impeller speed. In addition, the power consumption was found to be least for A320 impeller among the impellers investigated in this study.

Background: Dynamic simulation has been finding extensive application in modeling and simulation of various chemical processes. With the availability of high speed computers it has become customary to use Dynamic simulation to analyze various operating scenarios which not only include steady state scenarios but also dynamic situations like startup, planned shutdown and emergency shutdown. In this present work, various methods used to startup a compressor have been simulated. These scenarios were analyzed to find optimal power consumption and time requirements for startup of a model LNG compressor. This work gives some insight into how dynamic simulation can be used to evaluate different start up scenarios of a centrifugal compressor. Methods: We have modelled and simulated centrifugal compressor start up scenarios using Aspen Hysys and in each case made sure that compressor does not enter the surge region. We have compared the compressor power consumption in each scenario. Results: Based on the analysis of Dynamic Simulation we found that optimization of compressor power consumption is possible by studying different start up procedures. Conclusions: As shown in the above cases the compressor start up scenarios can be studied to optimize many parameters like power consumption, control valve opening time and discharge pressure variation. Out of the 3 cases studied with similar setup, the variable speed drive case with ASV being 60% initially and then reducing as the compressor starts, seems to consume lesser power and better discharge pressure. All these simulations exemplify the benefits of using dynamic simulation when designing and optimizing these kinds of systems. However, caution must be taken while selecting proper anti surge valve opening timings and compressor map characteristics.