Volume 16, Issue 7 -

In this article, the ZSM-5 catalyst was used as the base catalyst and its structure was modified for conducting Methanol to Gasoline reactions. ZSM-5 catalyst reacts to the solutions with diverse concentrations of calcium carbonate (CaCO 3 ) and sodium carbonate (Na 2 CO 3 ), and consequently, some changes were applied to its internal structure. Thus, Methanol to Gasoline (MTG) process was carried out under pressure of 1 atm, the temperature of 400°C, and specific surface area of 300 m2g-1 on synthetic zeolite ZSM-5 catalyst by a fixed-bed reactor. Structure and morphology of the synthesized catalyst were investigated by XRD, FT-IR, SEM, XRF and BET analyses. The effect of CaCO 3 and Na 2 CO 3 solutions used for catalyst modification on the distribution of hydrocarbon products were studied and compared to ZSM-5 catalyst. The result of catalyst activity evaluation tests shows that the modified catalyst with a 0.1 molar solution of CaCO 3 and Na 2 CO 3 provides the highest selectivity and efficiency compared to the hydrocarbons in boiling point range of C6+ gasoline.

Hydrogen can be one of the key elements as source of future energy requirement. Water splitting reaction is an important route for generation of hydrogen as maximum fraction of hydrogen constitute in water. The present work describes the experimental investigation for generation of hydrogen through water splitting reaction in flow conditions with the aid of metal aluminum and sodium hydroxide as an activator. The hydrogen generation through water splitting reaction at various concentrations of NaOH, viz. 0.5 N and 1 N and the flow rates ranging from 0.2 to 10 ml/min was studied. The yield of hydrogen generated is reported for each NaOH concentration and flow rate. The yield of hydrogen generated at all the considered concentrations and flow rates was found to be greater than 98 %. The shrinking core model has been modified and developed for predicting the conversion of aluminum in the reaction system as per the prevailing conditions and rate controlling mechanism. The RMSE value of predicted conversion of Al was found to be 0.0351 which signify that the model agrees well with the experimental data.

Supercritical water fluidized bed reactor, which is used to gasify biomass and produce hydrogen, is a new member of fluidized bed family. Forced convection heat transfer between supercritical water and particles is a major basic heat transfer mechanism in supercritical water fluidized bed reactor. The object of this paper was to determine the heat transfer characteristics for a forced convection between a spherical particle and supercritical water (SCW) in a range of pressure from 23 to 27 MPa and temperature from 637 to 697 K. A numerical model fully accounting for thermal physical property variation of SCW has been solved using a finite volume method with Reynolds number up to 200. Comparing with constant property flow, high velocity and temperature gradient in the vicinity of the particle surface were observed when the variable thermal physical property of SCW was incorporated in calculation. Based on the numerical results, a correlation that takes into account the large thermal physical property variation was proposed for predicting Nusselt number.

Reactive extraction of gallic acid (GA) from aqueous solution was studied using extractant TOA and Aliquat 336 in hexanol and a comparative analysis were made for optimum extractant-diluent system with two factor central composite design. The model equations were developed using 13 experimentations, each with TOA and Aliquat 336. TOA and Aliquat 336 gave antagonistic and synergistic effects respectively for extraction of GA. The optimum conditions were observed as C TOA = 8.6 %, C GA0 = 2.9 g/L and C ALQ = 33.2 %, C GA0 = 3 g/L with experimental extraction of 92.2 % and 96.5 % respectively. Lesser TOA and its non-toxicity for extraction of GA as compared to Aliquat 336 suggest TOA as better candidate in the prevailing conditions.

The reaction of acrylic acid and 2-ethyl-1 hexanol was explored in this work with the intent of process intensification. In order to assess the effect of important parameters on the course of reaction, this work initially conducted batch reactor experiments. Reaction conditions in the batch reactor for a specific conversion (~ 30 %) were obtained. A kinetic model was then obtained through regression to arrive at a rate expression that is later used in process development. Experiments were performed in the reactive distillation (RD) environment in batch mode, which showed substantial increase in conversion (~ 80 %) indicating the applicability of RD. Further, this work performed simulation in the RD environment to assess process intensification. Simulations show that it is possible to obtain complete conversion of the acid.

The kinetics of the heterogeneous reaction of metal aluminum with water was studied in presence of NaOH as an activator for generating the hydrogen. Aluminum (Al) powder of average size of 100 µm and foil of thickness of 11 µm were utilized to study the effect of the shape of particles of aluminum on hydrogen generation. The hydrogen generation was reported at various concentrations of NaOH, ranging from 0.12 N to 0.67 N. The fractional conversion of Al was found to be 0.66 at 0.12 N and 1.0 at 0.185 N, 0.37 N, 0.54 N, 0.65 N NaOH concentration. The activation energy of the reaction has been determined at the stoichiometric concentration of 0.185 N NaOH at the temperature ranging from 298 to 323 K. An attempt was made to model the reaction using Shrinking Core Model (SCM) for determining the rate controlling mechanism for the heterogeneous reaction. The reaction was observed to follow the first order kinetics and the average value of reaction rate constant using Al power and foil was found to be 27.322 x 10 -4 cm/min and 2.125 x 10 -4 cm/min respectively.

In this study, a novel swirl combustion modified device for steel slag was designed and enhanced with the objective of achieving highly efficient and clean coal combustion and also for achieving the whole elements utilization of coal. Coal ash and steel slag were melted in the combustion chamber and subsequently entered the slag chamber. The detrimental substances solidified and formed crystals, which allowed for the comprehensive utilization of the ash and slag. Our experiments mainly aimed to mitigate the formation of NO x , while using the heat and slag simultaneously during the coal combustion without a combustion efficiency penalty. The increase in the device’s energy efficiency and reduction in the NO x emissions are important requirements for industrialization. The experiments were carried out in an optimized swirling combustion device, which had a different structure and various coal feeding conditions in comparison to previously reported devices. The fuel-staged and non-staged combustion experiments were compared under different coal ratios (bitumite:anthracite). For the fuel-staged combustion experiments, the NO x concentration in the flue gas was observed to decrease significantly when the coal ratio of 1:1, an excess air coefficient of 1.2, and a fuel-staged ratio of 15:85 were used. Under these conditions, the flue gas temperature was as high as 1,620°C, while the NO x concentration was as low as 320 mg/m 3 at 6 % O 2 . The air-surrounding-fuel structure that formed in the furnace was very beneficial in reducing the formation of NO x . In comparison to other types of coal burners, the experimental combustion device designed in this study achieved a significant reduction of NO x emissions (approximately 80 %).

The pyrolysis behaviors of Shenhu subbituminous coal (SSBC) after pretreated with 1-ethyl-3-methylimidazolium acetate (EMIA) were studied in this paper. It is found that the pretreatment of SSBC with ionic liquid EMIA has a significant effect on the pyrolysis behavior of SSBC. The pretreatment temperature significantly affects tar yield of SSBC pyrolysis. The pretreatment SSBC with EMIA at 100 °C, 150 °C, 200 °C results in the increase of pyrolysis tar yield by 26.8 %, 32.8 %, and 35.7 %, respectively, compared to that of SSBC coal pyrolysis. FTIR and TG analysis show that EMIA pretreatment changed oxygen-containing functional groups in SSBC, in particular, increased the content of a carboxyl group and ether bond in SSBC. Also, it is found that pretreatment of coal with ionic liquid EMIA has a significant desulfurization effect.

This paper proposes a corrected kinetic model for the Sabatier (CO 2 Methanation) reaction. Several other kinetic studies have been performed on the Sabatier reaction to date; however, many of these studies contain simplifications. Data available from one of the first studies (Lunde, P.J., and F.L. Kester. 1974. “Carbon Dioxide Methanation on a Ruthenium Catalyst.” Industrial & Engineering Chemistry Process Design and Development 13 (1): 27–33) was utilized to perform a new analysis of the kinetics of CO 2 Methanation. This work examined two models for the Sabatier reaction, the Perfect Mixing assumption and the differential (conversion) reactor assumption. After available data was screened for the occurrence of the Reverse Water Gas Shift reaction, the differential (conversion) reactor assumption was validated. A critical comparison to similar models available in literature is also presented.

Enzymatic synthesis of molecules such as flavors, perfumes and fragrances has a great commercial advantage of being marketed as “natural” and also it offers exquisite selectivity of enzymes that can be superior over chemical catalysis. The current work focuses on the enzymatic synthesis of geranyl acetate as model compound, including optimization of reaction conditions such as nature of catalyst, reaction media, speed of agitation, mole ratio and temperature. A variety of esters were also synthesized. Geraniol was esterified with various acids, aromatic esters and vinyl esters in 1:4 molar ratio. Among all vinyl ester was the best giving in good yield (77–100 %) as compared to aromatic esters (5–82 %) and acids (7–31 %). Novozym 435 was found to be most active catalyst with ~96 % conversion and 100 % selectivity in 60 min at 55 °C in n-heptane as solvent for geranyl acetate. The maximum reaction rate was estimated (V max = 0.2712 mol L −1 min -1 ) by using the double reciprocal plot. It is a ternary complex (ordered bi-bi) mechanism with inhibition by geraniol.