Process Systems Engineering

Global warming is partly attributed to the off-gas from petrochemical plants. This can be utilized as a feed to produce hydrogen (H2) as a promising measure for battling climate change. In this study, we evaluated the potential for converting waste off-gas to H2 via steam-reforming technology accompanied by a carbon capture unit, through hybrid absorption/adsorption processes, to achieve a 99.99% hydrogen product. Also, the ReCiPe methodology was used for environmental analysis. The results showed that the equivalent greenhouse emissions when producing of 1 kg of H2 were 3.53 kg CO2-Eq, which were almost 2.5 times lower than those for H2 production without carbon capture, i.e., grey H2. Also, it was shown that using refinery gas as a reforming furnace fuel instead of conventional fuel oil led to about an 11% decrease in emissions

Chemical absorption using amineebased solvents have proven to be the most studied, as well as the most reliable and efficient technology for capturing carbon dioxide (CO 2) from exhaust gas streams and synthesis gas in all combustion and industrial processes. The application of single amineebased solvents especially the very reactive monoethanolamine (MEA) is associated with a parasitic energy demand for solvent regeneration. Since regeneration energy accounts for up to threeequarters of the plant operating cost, efforts in its reduction have prompted the idea of using blended amine solvents. This review paper highlights the success achieved in blending amine solvents and the recent and future technologies aimed at increasing the overall volumetric mass transfer coefficient, absorption rate, cyclic capacity and greatly minimizing both degradation and the energy for solvent regeneration. The importance of amine biodegradability (BOD) and low ecotoxicity as well as low amine volatility is also highlighted. Costs and energy penalty indices that influences the capital and operating costs of CO 2 capture process was also highlighted. A new experimental method for simultaneously estimating amine cost, degradation rate, regeneration energy and reclaiming energy is also proposed in this review paper.

Conducting polymer (CP) coatings have been extensively investigated for corrosion protection of iron, steel and other metals owing to their superior performance in highly aggressive environments and eco-friendly characteristics. Corrosion protective coatings based on CP nanocomposites have opened a new area of research for obtaining low cost coatings with enhanced performance and tailored properties. This mini review highlights the latest developments in the corrosion protective performance of CP composite coatings with natural resource derived polymers. The presence of nanoscale dispersion of CP as filler significantly improves the barrier properties and lifetime of the organic polymeric coatings. These low-cost nanocomposite coatings are expected to play an important role in combating corrosion which can lead to drastic improvement in corrosion protection.

In this study, highly concentrated tri-solvent blends containing 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ) and monoethanolamine (MEA) were experimentally investigated for their potential capabilities in carbon dioxide (CO2) capture. The concentration of both AMP and PZ were varied but their combined concentration (AMP + PZ) was kept at 3 kmol/m3 to limit the possibility of precipitation, the maximum PZ concentration (1.5 kmol/m3), and the total aqueous amine solution concentration (6 kmol/m3). At atmospheric pressure condition, the absorption process was carried out at 313 K and 15.1%v/v CO2 while 363 K was used for the desorption analysis. Experimental results indicated that all the AMP – PZ – MEA tri-solvent blends possessed higher cyclic capacities, initial desorption rates, and lower heat duties (50–54.5%) compared to the standard 5 kmol/m3 MEA. For the initial absorption rates, only the tri-solvent blends with AMP/PZ molar ratios of 1 and 2 were higher than 5 kmol/m3 MEA. These findings, most especially the significant reduction in heat duty by halve reveal the prospects of AMP – PZ – MEA tri-solvent blends for CO2 capture applications.

Gas-to-liquids (GTL) has emerged as a commercially-viable industry over the past thirty years offering market diversification to remote natural gas resource holders. Several technologies are now available through a series of patented processes to provide liquid products that can be more easily transported than natural gas, and directed into high value transportation fuel and other petroleum product and petrochemical markets. Recent low natural gas prices prevailing in North America are stimulating interest in GTL as a means to better monetise isolated shale gas resources. This article reviews the various GTL technologies, the commercial plants in operation, development and planning, and the range of market opportunities for GTL products.

The Fischer–Tropsch (F–T) technologies dominate both large-scale and small-scale projects targeting middle distillate liquid transportation fuel markets. The large technology providers have followed strategies to scale-up plants over the past decade to provide commercial economies of scale, which to date have proved to be more costly than originally forecast. On the other hand, some small-scale technology providers are now targeting GTL at efforts to eliminate associated gas flaring in remote producing oil fields. Also, potential exists on various scales for GTL to supply liquid fuels in land-locked gas-rich regions. Technology routes from natural gas to gasoline via olefins are more complex and have so far proved difficult and costly to scale-up commercially. Producing dimethyl ether (DME) from coal and gas are growing markets in Asia, particularly China, Korea and Japan as LPG substitutes, and plans to scale-up one-step process technologies avoiding methanol production could see an expansion of DME supply chains.

The GTL industry faces a number of challenges and risks, including: high capital costs; efficiency and reliability of complex process sequences; volatile natural gas, crude oil and petroleum product markets; integration of upstream and downstream projects; access to technology. This review article considers the GTL industry in the context of available opportunities and the challenges faced by project developers.

As concerns about rising fossil fuel prices, energy security, and climate change increase, renewable energy can play a key role in producing local, clean, and inexhaustible energy to supply Australia's growing demand for electricity, heat, and transportation fuel. Renewable energy is an essential part of Australia's low emissions energy mix and this energy is important to its energy security. Australia has some of the best renewable energy resources in the world. This paper will focus on the impact of these renewable energies in Australia. This study shows that Australia has the potential to secure its long term energy future through focus and encouragement on increasing utilisation of renewable energy.

This research covered the rate-based process simulation (ProMax® 4.0) and techno-economic analysis of carbon dioxide (CO2) capture from a 1.2 million metric tonne per annum cement plant using aqueous 2 kmol/m3 AMP-1 kmol/m3 PZ-2 kmol/m3 MEA blend. The waste gas composition for this study was provided by a cement plant from Quebec, Canada. The effect of amine type, energy penalty, and CO2 capture efficiency (50% to 90%) on the capture costs (US$/tonne CO2 and US$/tonne cement) were investigated. Sensitivity analysis on the impact of CO2 capture plant, carbon tax (US$ 20 to US$ 40 per tonne of CO2), CO2 sales price (US$ 10 to US$ 40 per tonne of CO2), energy penalty and CO2 capture efficiency on the cement price was also investigated. Results revealed that at 90% CO2 capture efficiency, the capture costs of AMP-PZ-MEA (US$77.34/tonne CO2 and US$44.94/tonne cement) is lower than that of MEA (US$93.23/tonne CO2 and US$54.17/tonne cement). Results also revealed that the total equipment cost and capital expenditure (CAPEX) of MEA system (US$ 29.76 million and US$ 147.12 million) higher than that of AMP-PZ-MEA blend (US$ 23.39 million and US$ 127.59 million).

Cash flow analysis showed that without adding a CO2 capture unit to a cement plant, carbon tax increased the cement price up to 22.9%. However, a combination of the high carbon tax, high CO2 sales price, low energy penalty, and high capture efficiency increased the cement price up to 1.2% for the MEA system but reduced the cement price up to 5% for the AMP-PZ-MEA system. This comprehensive study shows that a cost-effective and energy-efficient amine blend, energy penalty, CO2 capture efficiency, carbon tax, and CO2 sales prices are all integral towards reducing the cement price while significantly reducing the CO2 emissions.

This experimental study covered pilot plant analysis of novel AMP and 1,5–diamino–2–methylpentane (DA2MP) amine solvent blend for CO2 capture from a lime kiln. The gas flow rate (F(GAS)), amine solution flow rate (F(amine)), CO2 concentration and reboiler temperature (T(REB)) were kept at 14 SLPM, 50 mL/min, 30 vol.% CO2 (N2 balance) and 120 °C respectively. The AMP concentration was kept at 2 kmol/m3 while DA2MP was varied from 1.5 kmol/m3 to 2 kmol/m3. The MEA and AMP-DA2MP comparative analysis was based on rich amine loading (αrich, mol CO2/mol amine), lean amine loading (αlean, mol CO2/mol amine), cyclic loading (CL, mol CO2/mol amine), cyclic capacity (CC, mol CO2/L–amine soln.), CO2 absorption rate (rabs, g–CO2/hr), CO2 absorption efficiency (%), regeneration energy (Qreg, GJ/tonne CO2), absorber overall average volumetric mass transfer coefficient (KGav(ave), kmol/kPa.hr. m3), desorber mass transfer coefficient (KLav, hr–1), initial amine solution utilized (Aminesoln._utilized, g-amine soln./g-CO2) and initial amine solution cost (US$/g-CO2). The influence of sensible energy (Qsen, GJ/tonne CO2), vaporization energy (Qvap, GJ/tonne CO2), and desorption heat (ΔHdes, GJ/tonne CO2) towards regeneration energy (Qreg) was also examined. Results showed that the AMP-DA2MP blend possesses higher CO2 absorption efficiency (up to 36.17%), higher KGav(ave) (up to 65.85%), higher KLav (up to 28.29%) and lower Qreg (up to 32.54%) compared to the single solvent MEA. Also, MEA possessed higher initial amine solution utilized (28.86%) and lower initial amine solution cost (28.5%) compared to the AMP-DA2MP blend. This is an initial revelation that AMP-DA2MP can provide cost-effective CO2 capture from a lime kiln.

This study investigated the absorption heat, equilibrium CO2 solubility, absorption and desorption rates, cyclic capacities, heat duty, and absorption kinetic modeling of amine blends containing AMP and DETA. The AMP and DETA concentrations were varied (1–2.5 kmol/m3 and 0.5–2 kmol/m3, respectively) while the total amine concentration was constant at 3 kmol/m3. The absorption experiment was conducted at 15 %v/v CO2 and 313 K while the desorption temperature was at 363 K. Experimental results revealed that the absorption rates, cyclic capacities and desorption rates of some AMP–DETA blends were higher than those of 5 kmol/m3 MEA. The absorption heat of the blends is comparable to that of MEA while the heat duty of some AMP–DETA blends are much lower than that of 5 kmol/m3 MEA. The optimal amine blend was confirmed to be 2 kmol/m3 AMP – 1 kmol/m3 DETA. A model similar to the power law kinetic model showed that CO2 composition in the feed gas affected the initial absorption rates as compared to AMP/DETA molar concentration ratio. The model predicted the initial absorption rate with a %AAD of 0.52%. These results provide good prospects for AMP–DETA blends towards CO2 capture.

This study used ProMax® 4.0 process simulator (rate–based model) to conduct a parametric sensitivity of carbon dioxide (CO2) capture from a 115 MW coal–fired power plant (Boundary Dam 3 power plant) using monoethanolamine (MEA) and diethanolamine (DEA) blend. Saskatchewan Power Corporation (SaskPower), Canada provided the flue gas composition used in this study. The validated simulation was used to determine the effects of some process variables (independent process variables) on different dependent process variables. The independent process variables are flue gas temperature (TFG, oC), lean amine temperature (TLA, oC), lean amine flow rate (FLA, tonne/day), lean amine concentration difference (CMEA–DEA, kmol/m3) and reboiler temperature (TREB, oC). The dependent process variables are MEA and DEA vaporization from the absorber, CO2 absorption efficiency (%), regeneration energy (GJ/tonne CO2), rich amine loading (RAL, mol CO2/mol amine) and lean amine loading (LAL, mol CO2/mol amine). Amine degradation was investigated by the O2 absorption rate (tonne O2/day), NO absorption rate (tonne NO/day) and NO2 absorption rate (tonne NO2/day). The vaporization rates of MEA (tonne MEA/day) and DEA (tonne DEA/day) were also investigated. The contribution of amine and water make–up costs, regeneration energy, pump electrical energy, blower electrical energy and compressor electrical energy towards variable operating expenditure (V–OPEX) were also investigated. Results showed that NO also contributes to amine degradation. From the parametric analysis it was observed that TREB has the greatest influence on most of the dependent process variables. It was also discovered that the regeneration energy, compressor electrical energy and amine, water make–up cost and cooling water contributed 82.5%, 12.3%, 1.1%, 0.9% and 0.5% of the V–OPEX respectively.

Bench-scale pilot plant study of AMP and 1,5-diamino-2-methylpentane (DA2MP) blend for CO2 capture from gas-fired power plant is investigated. The concentration of the amine blend is 2 kmol/m3 AMP-1.5 kmol/m3 DA2MP while that of single solvent MEA is 5 kmol/m3. Comparative analysis was based on CO2 absorption efficiency (%), absorber mass transfer coefficient (KGav(ave), kmol/kPa h m3), desorber mass transfer coefficient (KLav, h−1), rich amine loading (αrich, mol CO2/mol amine), lean amine loading (αlean, mol CO2/mol amine), cyclic loading (CL, mol CO2/mol amine), cyclic capacity (CC, mol CO2/L-amine soln.), CO2 absorption rate (rabs, g-CO2/h), and regeneration energy (Qreg, GJ/tonne CO2). The contribution of sensible energy (Qsen, GJ/tonne CO2), vaporization energy (Qvap, GJ/tonne CO2), and desorption heat (ΔHdes, GJ/tonne CO2) towards Qreg was also investigated. Results showed that the AMP-DA2MP blend possess higher KGav(ave) (11.66%), KLav (7.67% higher), and CO2 absorption efficiency (4.66% higher) than MEA. Also, the superior cyclic loading (51.5%) and cyclic capacity (6.7%), and lower regeneration energy (13.8% lower) was observed for the AMP-DA2MP blend. The desorption heat (ΔHdes) was the major contributor to the Qreg of both amine systems however the ΔHdes of AMP-DA2MP was 23% lower than MEA. It was noticed that though the water concentration of the amine blend (60.7 wt%) is lower than MEA (70 wt%), the vaporization energy of the amine blend was 32.9% higher than MEA. Therefore, besides the amount of water concentration, higher desorber temperature profile, amine solvent vapor pressure and boiling point also increases the vaporization energy. The results is a revelation of possible reduction in capital cost and operating costs for the AMP-DA2MP blend compared to the standard MEA.

This research is a bench-scale pilot plant investigation of novel amine solvent blend containing MDEA and 1,5-diamino-2-methylpentane (DA2MP) for CO2 capture from water-gas shift process plant (H2 production). The CO2 concentration used in this study (50 vol.% CO2 with N2 balance) is similar to that of the water-gas shift product gas. The CO2 capture performance of the MDEA-DA2MP blend was compared to the standard 3 kmol/m3 MDEA-0.5 kmol/m3 PZ blend (34.4 wt.% MDEA-5 wt.% PZ). The low concentration of PZ in this study is because of the chemical toxicity of PZ and possible precipitation at medium to high concentration. The MDEA concentration in the MDEA-DA2MP blend was kept constant at 3 kmol/m3 while the DA2MP was varied from 0.5 kmol/m3 (6.75 wt.%) to 1.5 kmol/m3 (20.3 wt.%). The pilot plant analysis was performed at a gas flow rate, amine solution flow rate, and reboiler temperature of 14 SLPM, 50 mL/min, and 120 °C respectively. Pilot plant results revealed that the higher MDEA-DA2MP blend concentration possesses higher CO2 capture efficiency (up to 24%), higher CO2 absorption rate (up to 23.5%) and higher absorber mass transfer coefficient (up to 23.9%) compared to the MDEA-PZ blend. It was also discovered that the high MDEA-DA2MP concentration has lower regeneration energy (up to 25.4%), lower initial amine solution utilized (up to 20.5%), lower desorber mass transfer coefficient (up to 32.5%) compared to the MDEA-PZ blend. However, the optimal amine concentration is the 3 kmol/m3 MDEA-1 kmol/m3 DA2MP blend. Overall results show that the MDEA-DA2MP blend can offer a cost-effective and energy efficient CO2 capture compared to MDEA-PZ.

Md. Faysal Ahamed Khan, candidate for the degree of Master of Applied Science in Process Systems Engineering, has presented a thesis titled, Kinetic Study of Catalytic Partial Oxidation of Synthetic Diesel for Hydrogen Production, in an oral examination held on December 20, 2011. The following committee members have found the thesis acceptable in form and content, and that the candidate demonstrated satisfactory knowledge of the subject material.

This paper proposes a new approach of applying an optimization technique to simultaneously determine a physical liquid—film mass transfer coefficient (KoL) and effective interfacial area (av) from a pilot plant data. The mass transfer mechanism of the CO2‐NaOH system was modeled using the two‐film theory to represent the behaviors of packed absorbers. The model presents an overall absorption rate (Rv) as a function of KoL and av. The optimization algorithm used in this study follows a modified Levenberg‐Marquardt method with a trust region approach. The Rv predictions from the model are in good agreement with the experimental data, with an average error of 6.5%.

Kinetic, experimental, modeling and simulation studies of the carbon dioxide reforming of methane (CDRM) were performed in a catalytic packed bed reactor over a new Ni/CeO 2-ZrO 2 catalyst. Reactor modeling was performed using a comprehensive numerical model consisting of two-dimensional coupled material and energy balance equations. The kinetic model that best predicted the experimental rates was developed based on the Eley-Rideal (ER) formulation, assuming the methane dissociative adsorption as the rate-determining step. The best mechanistic kinetic model developed was incorporated in the reactor model which contained the axial dispersion term, and solved using the finite elements method. The validity of the reactor model was tested against the experimental data and a satisfactory agreement between the model prediction and measured results was obtained. In addition, the predicted concentration and temperature profiles for our process in the radial direction indicate that the assumption of plug flow isothermal behavior is justified within certain kinetic operating conditions. However, even when the well known criteria for neglecting the axial dispersion term have been met, there are differences in the values of conversion obtained with and without axial dispersion term.

Mechanistic kinetic models were formulated based on Langmuir-Hinshelwood-Hougen-Watson and Eley-Rideal approaches to describe the kinetics of hydrogen production by the catalytic reforming of concentrated crude ethanol over a Ni-based commercial catalyst at atmospheric pressure, temperature range of 673-863 K, ratio of weight of catalyst to the molar rate of crude ethanol 3472-34722 kg cat s/kmol crude in a stainless steel packed bed tubular microreactor. One of the models yielded an excellent degree of correlation, and was selected for the simulation of the reforming process which used a pseudo-homogeneous numerical model consisting of coupled material and energy balance equations with reaction. The model was solved using finite elements method without neglecting the axial dispersion term. The crude ethanol conversion predicted by the model was in good agreement with the experimental data (AAD% = 4.28). Also, the predicted concentration and temperature profiles for the process in the radial direction indicate that the assumption of plug flow isothermal behavior is justified within certain reactor configurations. However, the axial dispersion term still contributed to the results, and thus, cannot be neglected.