Aashish Gaurav | University of Waterloo (original) (raw)
Papers by Aashish Gaurav
A one-step process replacement for the conventional three step process for MIBK synthesis [1] is ... more A one-step process replacement for the conventional three step process for MIBK synthesis [1] is made possible by a robust, multifunctional catalyst that simultaneously facilitates the three major chemical transformations in a single catalytic distillation (CD) reactor. CD is a hybrid reactor technology that integrates heterogeneous catalytic reaction within a distillation column by immobilizing solid catalyst particles within discrete reactive sections, potentially resulting in significant energy savings as well as a reduction in operating and capital expenditures because of process intensification. CD processes are generally more energy efficient leading to a reduction of the emission of greenhouse gases.
Green Energy & Environment
Abstract Production of biodiesel from yellow grease (waste cooking oil and waste animal fats) is ... more Abstract Production of biodiesel from yellow grease (waste cooking oil and waste animal fats) is fast emerging as a promising alternative to address the twin challenges before the biodiesel industry today-fluctuation in prices of vegetable oil and the food versus fuel debate. Yellow grease has a high percentage of free fatty acids (FFA) and proves to be an unsuitable feedstock for biodiesel production from commercially viable alkali-catalyzed production systems due to saponification problems. “Green” methodologies based on heterogeneous solid acid catalyzed reactions have the potential to simultaneously promote esterification and transesterification reactions of yellow grease to produce biodiesel without soap formation and offer easy catalyst separation without generation of toxic streams. This paper presents kinetic studies for the conversion of model yellow grease feeds to biodiesel using a heteropolyacid supported on alumina (HSiW/Al2O3) using a batch autoclave. Three model yellow grease feeds were prepared using canola oil with added FFA such as palmitic, oleic and linoleic acid. A pseudo homogeneous kinetic model for the parallel esterification and transesterification was developed. The rate constants and activation parameters for esterification and transesterification reactions for the model yellow grease feeds were determined. The rate constants for esterification are higher than the transesterification rate constants. The kinetic model was validated using the experimental biodiesel data obtained from processing a commercial yellow grease feed. The kinetic model could be used to design novel processes to convert various low-value waste oils, fats and non-food grade oils to sustainable biodiesel.
Green Energy & Environment, 2016
Industrial & Engineering Chemistry Research, 2015
ABSTRACT Isooctane is a valuable octane enhancer for gasoline and the primary component of aviati... more ABSTRACT Isooctane is a valuable octane enhancer for gasoline and the primary component of aviation gasoline, also known as Avgas because of its high anti-knock quality. Conventional industrial processes for isooctane production involve the steps of dimerization of isobutene, dimer separation and hydrogenation. The efficacy of catalytic distillation (CD) and its merits, in terms of energy savings and reduction of greenhouse gases emissions for the production of isooctane is quantitatively presented. The feed considered for the isooctane production is comprised of isobutene (C4) and inerts (isopentane) produced in refineries as by-products of steam cracking of naphtha and light gas oil. Process flow sheets for the two routes for the production of isooctane, with and without CD, are modeled. The conventional industrial flow sheet composed of a dimerization reactor, distillation column, and a hydrogenation reactor (Configuration A), is simulated using ASPEN PLUS. The intensified process flow sheet comprising a CD column, for the dimerization, hydrogenation, and separation, (Configuration B) is modeled using gPROMS. A validated, non-equilibrium, three-phase model is developed in a gPROMS environment and is used to quantify the energy savings and reduction of carbon dioxide emissions achieved using a CD column for the intensified process. Results demonstrate CD to be a promising candidate to replicate the conversions and product purity obtained in the conventional process while bringing significant energy savings, more efficient utilization of isobutene feed together with reduced carbon dioxide emissions.
Journal of Applied Polymer Science, 2012
Energy & Fuels, 2013
ABSTRACT The efficacy of catalytic distillation (CD) and the economic merits that it would bring ... more ABSTRACT The efficacy of catalytic distillation (CD) and the economic merits that it would bring into the biodiesel production process is studied. Process flow sheets depicting conventional and CD technology are modeled in Aspen Plus, and detailed operating conditions and equipment designs are provided for each process. The feedstock considered is soybean oil, and the transesterification reaction for the triglyceride is considered for biodiesel production. After optimal design of both process flow sheets to produce 10 million gallons of biodiesel per year, adhering to ASTM purity standards, a detailed cost analysis is carried out using the Aspen economic analyzer tool to predict capital, operating, and utility costs and to calculate the cost of production per gallon of biodiesel. Results depict CD to be a promising candidate to replicate the conversion and product purity of conventional biodiesel processes while having significant savings in capital (41.42% cheaper than the conventional process) and utility (18.12% less than the conventional process) costs, thereby making it a very competitive alternative. The total operating costs and price of production per gallon of biodiesel are only meagerly cheaper for a CD process because the most significant factor to the biodiesel production process is the raw material cost. For both processes, the price of production per gallon of biodiesel after accounting for revenue generated from glycerol product is predicted to be around 1.7 dollars/gallon. The Aspen model is flexible to accommodate higher flow rates for scale-up of operations, add or remove stages of operation into the biodiesel process, modify feedstock and stream prices, and predict associated capital and production costs.
The challenges in the chemical processing industry today are environmental concerns, energy and c... more The challenges in the chemical processing industry today are environmental concerns, energy and capital costs. Catalytic distillation (CD) is a green reactor technology which combines a catalytic reaction and separation via distillation in the same distillation column. Utilization of CD in chemical process development could result in capital and energy savings, and the reduction of greenhouse gases. The efficacy of CD and the economic merits, in terms of energy and equipment savings, brought by CD for the production of biodiesel from waste oil such as yellow grease is quantified. Process flow sheets for industrial routes for an annual production of 10 million gallon ASTM purity biodiesel in a conventional process (reactor followed by distillation) and CD configurations are modeled in Aspen Plus. Material and energy flows, as well as sized unit operation blocks, are used to conduct an economic assessment of each process. Total capital investment, total operating and utility costs are calculated for each process. The waste oil feedstock is yellow grease containing both triglyceride and free fatty acid. Both transesterification and esterification reactions are considered in the process simulations. Results show a significant advantage of CD compared to a conventional biodiesel processes due to the reduction of distillation columns, waste streams and greenhouse gas emissions. The significant savings in capital and energy costs together with the reduction of greenhouse gases demonstrate that process intensification via CD is a feasible and new green process for the biodiesel production from waste oils.
Isooctane is a valuable octane enhancer for gasoline and the primary component of aviation gasoli... more Isooctane is a valuable octane enhancer for gasoline and the primary component of aviation gasoline, also known as Avgas because of its high anti-knock quality. Conventional industrial processes for isooctane production involve the steps of dimerization of isobutene, dimer separation and hydrogenation. The efficacy of catalytic distillation (CD) and its merits, in terms of energy savings and reduction of greenhouse gases emissions for the production of isooctane is quantitatively presented. The feed considered for the isooctane production is comprised of isobutene (C4) and inerts (isopentane) produced in refineries as by-products of steam cracking of naphtha and light gas oil. Process flow sheets for the two routes for the production of isooctane, with and without CD, are modeled. The conventional industrial flow sheet composed of a dimerization reactor, distillation column, and a hydrogenation reactor (Configuration A), is simulated using ASPEN PLUS. The intensified process flow sheet comprising a CD column, for the dimerization, hydrogenation, and separation, (Configuration B) is modeled using gPROMS. A validated, non-equilibrium, three-phase model is developed in a gPROMS environment and is used to quantify the energy savings and reduction of carbon dioxide emissions achieved using a CD column for the intensified process. Results demonstrate CD to be a promising candidate to replicate the conversions and product purity obtained in the conventional process while bringing significant energy savings, more efficient utilization of isobutene feed together with reduced carbon dioxide emissions. Keywords: Isooctane, Catalytic Distillation, Energy Efficiency, gPROMS, Process intensification, reduction of carbon dioxide emissions, high octane gasoline
A one-step process replacement for the conventional three step process for MIBK synthesis [1] is ... more A one-step process replacement for the conventional three step process for MIBK synthesis [1] is made possible by a robust, multifunctional catalyst that simultaneously facilitates the three major chemical transformations in a single catalytic distillation (CD) reactor. CD is a hybrid reactor technology that integrates heterogeneous catalytic reaction within a distillation column by immobilizing solid catalyst particles within discrete reactive sections, potentially resulting in significant energy savings as well as a reduction in operating and capital expenditures because of process intensification. CD processes are generally more energy efficient leading to a reduction of the emission of greenhouse gases.
Green Energy & Environment
Abstract Production of biodiesel from yellow grease (waste cooking oil and waste animal fats) is ... more Abstract Production of biodiesel from yellow grease (waste cooking oil and waste animal fats) is fast emerging as a promising alternative to address the twin challenges before the biodiesel industry today-fluctuation in prices of vegetable oil and the food versus fuel debate. Yellow grease has a high percentage of free fatty acids (FFA) and proves to be an unsuitable feedstock for biodiesel production from commercially viable alkali-catalyzed production systems due to saponification problems. “Green” methodologies based on heterogeneous solid acid catalyzed reactions have the potential to simultaneously promote esterification and transesterification reactions of yellow grease to produce biodiesel without soap formation and offer easy catalyst separation without generation of toxic streams. This paper presents kinetic studies for the conversion of model yellow grease feeds to biodiesel using a heteropolyacid supported on alumina (HSiW/Al2O3) using a batch autoclave. Three model yellow grease feeds were prepared using canola oil with added FFA such as palmitic, oleic and linoleic acid. A pseudo homogeneous kinetic model for the parallel esterification and transesterification was developed. The rate constants and activation parameters for esterification and transesterification reactions for the model yellow grease feeds were determined. The rate constants for esterification are higher than the transesterification rate constants. The kinetic model was validated using the experimental biodiesel data obtained from processing a commercial yellow grease feed. The kinetic model could be used to design novel processes to convert various low-value waste oils, fats and non-food grade oils to sustainable biodiesel.
Green Energy & Environment, 2016
Industrial & Engineering Chemistry Research, 2015
ABSTRACT Isooctane is a valuable octane enhancer for gasoline and the primary component of aviati... more ABSTRACT Isooctane is a valuable octane enhancer for gasoline and the primary component of aviation gasoline, also known as Avgas because of its high anti-knock quality. Conventional industrial processes for isooctane production involve the steps of dimerization of isobutene, dimer separation and hydrogenation. The efficacy of catalytic distillation (CD) and its merits, in terms of energy savings and reduction of greenhouse gases emissions for the production of isooctane is quantitatively presented. The feed considered for the isooctane production is comprised of isobutene (C4) and inerts (isopentane) produced in refineries as by-products of steam cracking of naphtha and light gas oil. Process flow sheets for the two routes for the production of isooctane, with and without CD, are modeled. The conventional industrial flow sheet composed of a dimerization reactor, distillation column, and a hydrogenation reactor (Configuration A), is simulated using ASPEN PLUS. The intensified process flow sheet comprising a CD column, for the dimerization, hydrogenation, and separation, (Configuration B) is modeled using gPROMS. A validated, non-equilibrium, three-phase model is developed in a gPROMS environment and is used to quantify the energy savings and reduction of carbon dioxide emissions achieved using a CD column for the intensified process. Results demonstrate CD to be a promising candidate to replicate the conversions and product purity obtained in the conventional process while bringing significant energy savings, more efficient utilization of isobutene feed together with reduced carbon dioxide emissions.
Journal of Applied Polymer Science, 2012
Energy & Fuels, 2013
ABSTRACT The efficacy of catalytic distillation (CD) and the economic merits that it would bring ... more ABSTRACT The efficacy of catalytic distillation (CD) and the economic merits that it would bring into the biodiesel production process is studied. Process flow sheets depicting conventional and CD technology are modeled in Aspen Plus, and detailed operating conditions and equipment designs are provided for each process. The feedstock considered is soybean oil, and the transesterification reaction for the triglyceride is considered for biodiesel production. After optimal design of both process flow sheets to produce 10 million gallons of biodiesel per year, adhering to ASTM purity standards, a detailed cost analysis is carried out using the Aspen economic analyzer tool to predict capital, operating, and utility costs and to calculate the cost of production per gallon of biodiesel. Results depict CD to be a promising candidate to replicate the conversion and product purity of conventional biodiesel processes while having significant savings in capital (41.42% cheaper than the conventional process) and utility (18.12% less than the conventional process) costs, thereby making it a very competitive alternative. The total operating costs and price of production per gallon of biodiesel are only meagerly cheaper for a CD process because the most significant factor to the biodiesel production process is the raw material cost. For both processes, the price of production per gallon of biodiesel after accounting for revenue generated from glycerol product is predicted to be around 1.7 dollars/gallon. The Aspen model is flexible to accommodate higher flow rates for scale-up of operations, add or remove stages of operation into the biodiesel process, modify feedstock and stream prices, and predict associated capital and production costs.
The challenges in the chemical processing industry today are environmental concerns, energy and c... more The challenges in the chemical processing industry today are environmental concerns, energy and capital costs. Catalytic distillation (CD) is a green reactor technology which combines a catalytic reaction and separation via distillation in the same distillation column. Utilization of CD in chemical process development could result in capital and energy savings, and the reduction of greenhouse gases. The efficacy of CD and the economic merits, in terms of energy and equipment savings, brought by CD for the production of biodiesel from waste oil such as yellow grease is quantified. Process flow sheets for industrial routes for an annual production of 10 million gallon ASTM purity biodiesel in a conventional process (reactor followed by distillation) and CD configurations are modeled in Aspen Plus. Material and energy flows, as well as sized unit operation blocks, are used to conduct an economic assessment of each process. Total capital investment, total operating and utility costs are calculated for each process. The waste oil feedstock is yellow grease containing both triglyceride and free fatty acid. Both transesterification and esterification reactions are considered in the process simulations. Results show a significant advantage of CD compared to a conventional biodiesel processes due to the reduction of distillation columns, waste streams and greenhouse gas emissions. The significant savings in capital and energy costs together with the reduction of greenhouse gases demonstrate that process intensification via CD is a feasible and new green process for the biodiesel production from waste oils.
Isooctane is a valuable octane enhancer for gasoline and the primary component of aviation gasoli... more Isooctane is a valuable octane enhancer for gasoline and the primary component of aviation gasoline, also known as Avgas because of its high anti-knock quality. Conventional industrial processes for isooctane production involve the steps of dimerization of isobutene, dimer separation and hydrogenation. The efficacy of catalytic distillation (CD) and its merits, in terms of energy savings and reduction of greenhouse gases emissions for the production of isooctane is quantitatively presented. The feed considered for the isooctane production is comprised of isobutene (C4) and inerts (isopentane) produced in refineries as by-products of steam cracking of naphtha and light gas oil. Process flow sheets for the two routes for the production of isooctane, with and without CD, are modeled. The conventional industrial flow sheet composed of a dimerization reactor, distillation column, and a hydrogenation reactor (Configuration A), is simulated using ASPEN PLUS. The intensified process flow sheet comprising a CD column, for the dimerization, hydrogenation, and separation, (Configuration B) is modeled using gPROMS. A validated, non-equilibrium, three-phase model is developed in a gPROMS environment and is used to quantify the energy savings and reduction of carbon dioxide emissions achieved using a CD column for the intensified process. Results demonstrate CD to be a promising candidate to replicate the conversions and product purity obtained in the conventional process while bringing significant energy savings, more efficient utilization of isobutene feed together with reduced carbon dioxide emissions. Keywords: Isooctane, Catalytic Distillation, Energy Efficiency, gPROMS, Process intensification, reduction of carbon dioxide emissions, high octane gasoline