Science of the Total Environment 664 (2019) 567–575 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv Potential of tri-reforming process and membrane technology for improving ammonia production and CO2 reduction Ahmad Taghizade Damanabi a, Morteza Servatan a, Saeed Mazinani a,⁎, Abdul Ghani Olabi b,c, Zhien Zhang d,⁎ a Process Engineering for Sustainable Systems, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium Sustainable and Renewable Energy Engineering, University of Sharjah, Sharjah, United Arab Emirates Mechanical Engineering and Design, School of Engineering and Applied Science, Aston University, Aston Triangle, Birmingham B4 7ET, UK d William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA b c H I G H L I G H T S G R A P H I C A L A B S T R A C T • A tri-reforming process was coupled with a membrane separation unit to enhance the ammonia synthesis process efﬁciency. • Increasing temperature and decreasing pressure improved the hydrocarbons conversion and H2/CO ratio. • The proposed strategy increased NH3 production and reduced CO2 emission simultaneously. a r t i c l e i n f o Article history: Received 7 December 2018 Received in revised form 28 January 2019 Accepted 29 January 2019 Available online 30 January 2019 Editor: Damia Barcelo Keywords: CO2 emission NH3 synthesis process Tri-reforming process Perovskite membrane a b s t r a c t In this work, a tri-reforming process was coupled with a membrane separation unit to enhance efﬁciency of ammonia (NH3) synthesis process in terms of CO2 emission, NH3 production, and NOx emission. Primary and secondary reformers were replaced by a tri-reforming process, while a Perovskite membrane was applied to separate nitrogen (N2) from oxygen (O2). A conventional NH3 synthesis process and the proposed process were simulated by Aspen-Hysys and compared in order to investigate the performance of the proposed sterategy. The simulation results indicated that when temperature increased and pressure decreased, conversion of hydrocarbons and H2/CO ratio were improved from 1.73 to 2.54, which resulted in an increase in NH3 production by 27 %, and a decrease in CO2 emission rate from 1192 kg/h to approximately 1 kg/h. The proposed sterategy was optimized in terms of different parameters e.g., temperature and pressure. Optimum reaction pressure and temperature were determined to be between 1 and 10 bar and 500–800 °C, respectively. The results of the study revealed that the proposed strategy not only removed amine and methanol sweeteners which reduce the operational costs of the process, but also decreased the NOx content from 8220 ppm to almost 10 ppm. © 2019 Elsevier B.V. All rights reserved. ⁎ Corresponding authors. E-mail addresses: email@example.com (S. Mazinani), firstname.lastname@example.org (Z. Zhang). https://doi.org/10.1016/j.scitotenv.2019.01.391 0048-9697/© 2019 Elsevier B.V. All rights reserved. 568 A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 1. Introduction Ammonia (NH3) signiﬁcantly contributes to nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. NH3, either directly or indirectly, is used as a building block for synthesis of many pharmaceutical or commercial cleaning products (Lam et al., 2018; Arora et al., 2018; Jeremiaš et al., 2014). Additionally, NH3 can be used for chemical processes in which an energy carrier is needed (Bicer et al., 2017; Bicer and Dincer, 2018a; Jain et al., 2017). According to annual energy report (Bicer and Dincer, 2018a), approximately 2 % of the world's commercial energy (as fossil fuels) is consumed for NH3 synthesis. It was also reported that 245 million tons of CO2 was released by the NH3 industry in 2010 (Bicer and Dincer, 2018b). Thus, it is essential to improve the NH3 synthesis process in order to signiﬁcantly reduce CO2 emissions, as the most important cause of greenhouse effect (Mazinani et al., 2018; Mazinani et al., 2015; Pan et al., 2018). NH3 is produced by the Haber process in a synthesis reactor at pressure of 200–300 bar and temperature of 400–600 °C. The hydrogen (H2) required for the process is produced by methane (CH4) reforming using a mixture of steam and air (Bicer et al., 2017). The CO2 produced during the CH4 steam reforming reaction is removed by an amine absorption unit, while the required N2 is provided through air injection into the reformer reactors. The efﬁciency of the process depends signiﬁcantly upon the H 2 production rate (Bicer et al., 2017). Trireforming process is a new technology that has recently been used to increase H2 production and recycle produced CO2. In this process, steam, oxygen (O2), and CO2 are used for CH4 reforming and generating synthesis gas. The use of tri-reforming actually increases produced H2 and consequently, enhances NH 3 production along with reduction in production costs (Damanabi and Bahadori, 2017; Dwivedi et al., 2018; Sadeghi et al., 2018). Recent studies showed that the use of tri-reforming process can reduce energy consumption and increases the efﬁcienty of process (Sadeghi et al., 2018; Katarzyna et al., 2017; Song and Pan, 2004). Much research has been done on optimizing and improving the NH3 production process. The research can be divided into four aspects: 1source of feed, 2- reduction of CO2 emissions, 3- decreasing the required energy for the process, and 4- using other systems such as membrane systems (Bicer and Dincer, 2018a). The main feed for NH3 production is N2 and H2 produced from water (H2O) electrolysis (Jain et al., 2017); however, the other resources including natural gas (Lu et al., 2015; Frattini et al., 2016; Amin et al., 2013) and biomass (Arora et al., 2017; Zhao et al., 2011; Andersson and Lundgren, 2014) have been investigated recently. The second aspect is related to reducing CO2 emissions to the atmosphere. Several methods have been proposed for reduction of CO2 production such as injection of produced CO2 into oil reservoirs for secondary oil recovery as an enhanced oil recovery (EOR) method (Bicer and Dincer, 2018b), implementing biomass as feed (Gilbert et al., 2014; Zhang et al., 2018a; Zhang et al., 2018b), and enhancing the efﬁciency of the process (Bicer et al., 2016). Energy consumption of the process needs to be improved and optimized (Bicer and Dincer, 2017). Finally, the last aspect is application of membranes for increasing the efﬁciency of NH3 production and decreasing the required energy. Separation of some materials from reaction zone increases the equilibrium reactions' efﬁciency (Orrego and Junior, 2016; Damanabi and Bahadori, 2018; Psara et al., 2015). The application of membranes in chemical reaction processes is now largely concentrated in H2 and O2-containing reaction systems. Different types of ceramic membranes could be used for air separation to its components such as O2. Recently, perovskite membranes have attracted much attention due to excellent O2 permeability and good stability at high temperatures and pressures. Actually, the resistance of perovskite membranes versus thermo-mechanical and chemical decomposition at high temperatures is decisive to use it (Ghadimi et al., 2011; Hu et al., 2018; Lu et al., 2018). The parameters that inﬂuence the O2 permeation in the perovskite membranes include operating temperature and pressure, membrane thickness, feed ﬂow rate, and purity of the feed (Ghadimi et al., 2011). In this work, a tri-reforming process was associated with a membrane separation unit in NH3 synthesis process in order to reduce CO2 emissions and increase NH3 production, simultaneously. A perovskite membrane was eomployed to separate N2 from O2. The conventional and proposed processes were simulated and compared in terms of CO2 emission, NH3 production and NOx emission to evaluate the performance of the proposed process. Additionally, in order to optimize the proposed process, the effects of different parameters e.g., temperature and pressure have been evaluated. 2. Methodology 2.1. Assumption The main assumptions for this model are listed below: • The simulation was peformed in steady state condition. • Pressure drop along the NH3 synthesis reactor was considered to be ignorable. However, in other reactors, pressure was computed from Ergun equation. • All the reactors were simulated in shell and tube form. 2.2. Process description One of the most commonly used methods for producing synthesis gas is reforming of natural gas or naphtha with steam (Dincer, 2012). Generally, the NH3 production stages can be summarized in Fig. 1. Catalysts used in the NH3 synthesis are sensitive to sulfur, so the ﬁrst step is to remove sulfur compounds, mostly hydrogen sulﬁde (H2S) and thiol, from natural gas. The sulfur compounds are removed by passing the natural gas through an active carbon or zinc oxide substrate. H2S can be removed at different temperatures, in this simulation it was removed at temperatures between 370 and 400 °C (highest efﬁciency of removal). Steam reforming reactions are carried out in two steps. In the primary reformer, the catalysts are placed in tubes with a diameter of 0.1 cm, which are heated in a furnace. Steam and feed (with 3 to 1 ratio) are introduced into the reformer, at a pressure of 30 atm and 370 °C, where reforming reactions are carried out. The residence time in the reformer is not long enough so the reforming reactions are not complete. Therefore, the outlet contain signiﬁcant amounts of hydrocarbons along with H2, CO, CO2 and steam. CH 4 þ H2 O→CO þ 3 H 2 ð1Þ CH 4 þ 2 H 2 O→CO2 þ 4 H2 ð2Þ Hot gases emitted from the primary reformer along with air are injected to the catalyst bed of the secondary reformer. The gas from the secondary reformer consists of N2, H2, CO, CO2, steam and a small amount of CH4. CO2 poisons the synthesized catalysts and thus should be completely removed from the synthesis gas. CH 4 þ 0:5O2 →CO þ 2H 2 CH 4 þ O2 →CO2 þ 2H 2 ð3Þ ΔH ¼ −880 kJ=mol ð4Þ After the reformer reactors, the synthesis gas is introduced into water-gas shift (WGS) reactors. The goal here is to convert carbon monoxide (CO) into CO2 through a WGS reaction: H 2 O þ CO↔H 2 þ CO2 ð5Þ A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 569 Fig. 1. A schematic of conventional NH3 production unit. The reaction would be desirable at lower temperatures, however, with decreasing temperature the reaction rate will be decreased. Thus, in order to achieve an optimal temperature, the WGS reactions are usually take place in two steps at high temperatures and low temperatures. First, the reactions are carried out at a high temperature of about 400 °C in the presence of an iron oxide catalyst, and then carried out at a low temperature of 200 °C using a copper-zinc catalyst. The next step is to remove CO2, which is usually done using chemical absoprtion by potassium carbonate solution or monoethanolamine (MEA). The last remaining COx is eliminated by methanation in accordance with relations (6) and (7) by passing gas through the bed of a nickel catalyst at 350 °C, the reforming reaction is diverted to the original material and the carbon components are converted to CH4 and steam: CO þ 3 H 2 →CH 4 þ H 2 O CO2 þ 4H 2 →CH4 þ 2 H2 O ð6Þ ΔH ¼ þ247 kJ=mol ð7Þ The outlet gas is cooled and the condensed steam is used again to produce the synthesis gas. Table 1 and Eq. (8) show Arrthenius kinetic parameters for Eq. (1) to Eq. (3) and Eq. (5) to Eq. (6). K j ¼ kj e E −RTj ð8Þ In Eq. (8), kj is pre-coefﬁcient exponential, Ej is activation coefﬁcient and R is gas constant. The feed enters the NH3 reactor after passing through the compressor and heat exchangers. In this reactor, an aluminum oxide catalyst is used. The NH3 produced in accordance with Eq. (8) is separated off by a three phase separator and the unreactive gases are returned to the reactor through a compressor. Table 2 and Eq. (11) show Arrthenius kinetic parameters for Eq. (10). N2 þ 3H 2 ↔2NH3 0 RNH3 P N2 ¼ @K 1 K eq 2 K i ¼ Ai e E −RTi ð9Þ P 3H2 P2NH3 !1−β −K 1 P2NH3 P 3H2 !β 1 A ð10Þ ð11Þ In Eq. (10) and Eq. (11), β = 0.27 for the Al2O3 base catalyst is obtained at 573–723 K (Araujo and Skogestad, 2008). Fig. 2 shows the simulation process of a conventional NH3 production. 2.3. Process optimization In the NH3 synthesis process, CH4 is ﬁrstly desulfurized by the zinc oxide adsorbents and then converted to synthesized gas by the reformers. Synthesis gas produced is sent to the amine unit to remove CO2. The sweet stream is introduced into the methanator reactor for further separation of CO2. The outlet from the methanator reactor is sent to Table 1 Reaction Arrhenius kinetic parameters (Rahimpour et al., 2012). Reaction no. 1 2 3 5 6 kj (mol/(kgCat·s)) Ej (J/mol) 1187.55 2872.45 8231.65 114.17 39,638.3 240,100 243,900 86,000 58,826.3 83,423.9 Table 2 Arrhenius kinetic parameters in the NH3 synthesis reaction (Araujo and Skogestad, 2008). Reaction no. 1 2 kj (mol/(kgCat·s)) Ej (J/mol) 1.79 × 104 2.75 × 1016 87,090 198,464 570 A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 Fig. 2. Simulation of a conventional NH3 production unit (a) synthesis gas production section, (b) sweeting and methanator section, and (c) NH3 synthesis section. the NH3 synthesis reactor. In order to improve the efﬁciency of this unit, a tri-reformer reactor was used instead of the reformers, and a palladium silver (Pd/Ag) membrane was employed to enhance the purity of H2 and to complete the removal of CO2 and CO. To reduce the air pollutants, a perovskite membrane is used to separate N2 from O2 for NH3 synthesis. The schematic of the proposed process is shown in Fig. 3. A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 571 Fig. 3. Schematic of the tri-reforming and membrane system proposed for NH3 process. A tri-reforming reactor has been used to improve the efﬁciency of the oxidation reactions (Eq. (1) to Eq. (5)). The reactions initiate over the nickel-based catalyst as follow (Damanabi and Bahadori, 2017; Zhang et al., 2013): CH4 þ H2 O→CO þ 3H2 ð12Þ CH4 þ 0:5O2 →CO þ 2H 2 ð13Þ CH4 þ CO2 →2CO þ 2H 2 ð14Þ CH 4 þ O2 →CO2 þ 2H 2 ΔH ¼ −880 kJ=mol ð15Þ CH 4 →C þ 2H 2 ΔH ¼ þ75 kJ=mol 2CO↔CO2 þ C ΔH f ¼ −172 kJ=mol; ΔHrev ¼ þ172 kJ=mol ð17Þ C þ H 2 O→CO þ H2 C þ O2 →CO2 ΔH ¼ þ131 kJ=mol ΔH ¼ −394 kJ=mol ð16Þ (contains CO), part of it, is transferred to the methanol unit, and the rest sent to the other units (for instance to be used for production of Phosgene). In NH3 synthesis, the air entering the second reformer is used to supply N2 and O2 for synthesis gas production. This would lead to, due to the high pressure and temperature operating in the NH3 production unit, production of air pollutants such as NOx. Perovskite membranes have high selectivity for O2 and can provide O2 and N2 needed to synthesize gas and NH3. For this purpose, after compressing the air and increasing its temperature, it has been sent to the permeate side of the membrane. The N2 from the retentate is sent to the NH3 synthesis reactor and its pressure increased. The O2 is (from the permeate phase) is sent to the tri-reformimg reactor to be used for production of synthesis gas. 3. Results and discussion ð18Þ 3.1. Optimization of syngas ð19Þ The results of this section are divided in two categories including trireforming reactor, and membrane process. The products of tri-reforming reactors which consist of H2 and COx components are delivered to the Pd/Ag membrane unit. As shown in Fig. 4, the membrane, which has high selectivity for H2, separates H2 by about 99.99%. The puriﬁed H2 is sent to the NH3 synthesis reactor (after pre-heating) by a compressor to produce NH3. The waste stream 3.1.1. Tri-reforming reactor As it was discussed before, reaction (5), and reactions (12) to (14) are the main reactions inside the tri-reforming reactor. The reaction's conversion is mostly related to the operating condition of the tri- Fig. 4. Simulation of the proposed process for NH3 production using tri-reforming and membranes. 572 A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 Fig. 5. Conversion of CH4, steam and CO2 in tri-reforming reactor as a function of pressure. reforming reactor. Generally, in gas phase reactions, pressure plays an important role in altering the overall conversion. Fig. 5 demonstrates the effects of reactor pressure on the conversion of CH4, steam, and CO2. It is observed that increasing the pressure decreases the conversion of reaction (5) and reactions (12) to (14). Therefore, decreasing the pressure to an amount as low as possible enhances the overall conversion of the reactor. The effect of pressure on selectivity of products in tri-reforming reactor is another issue which should be considered. Fig. 6 shows the H2/CO ratios in tr–reforming reactor as a function of temperature, the H2/CO ratios are 3.73 and 2.2 in 600 °C and 800 °C, respectively. As it can be seen, in Fig. 6, increasing the reactor pressure detracts H2/CO ratio. As CO can deactivate the catalyst, it is rational to keep the H2/CO ratio in higher amounts. So, the low pressure is desired for high H2/CO ratios. By raising the temperature, H2/CO ratio reduces moderately. In fact, according to the Le Chatelier's principle at high temperatures, the reverse reaction of WGS produces more CO (Damanabi and Bahadori, 2017). On the other hand, according to Eqs. (15) to (19), an increase in temperature results in increase of coke production and thus the catalyst will be deactivated. Fig. 7(a), (b), and (c) displays ﬂow rates of O2, CO2 and steam at temperatures 500–800 °C along with their effects on the conversion of CH4. It is seen that higher ﬂow rates of O2 signiﬁcantly alters the CH4 conversion, i.e. increasing the O2 ﬂow rate from 10 kmol/h to 100 kmol/h, Fig. 7. Effects of different ﬂow rates of (a) O2, (b) CO2, and (c) steam on conversion of CH4 at temperatures between 500–800 °C. Fig. 6. Effects of pressure on H2/CO production ratio in tri-reforming reactor. and conversion of CH4 from 48% to 95% at 600 °C. At temperatures above 700 °C, difference between O2 injection rates (50 kmol/h and 100 kmol/h) seems to be negligible, so the O2 injection rate was set to be 50 kmol/h. The effects of CO2 injection rate on CH4 conversion are graphicaly shown in Fig. 7(b). It is clear that CO2 injection effect on CH4 conversion is ignorable in comparison with O2, i.e. at 600 °C. Increasing the CO2 injection rate from 0 to 100 kmol/h, elevates the CH4 A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 573 can be seen that increasing the steam ﬂow rate raised the conversion of CH4. In fact, this is the reason why the injection rate of 150 kmol/h was assumed for the steam. The conversions of CH4, CO2, and steam in the tri-reforming reactor for temperatures between 500 °C to 800 °C are displayed in Fig. 8. According to Fig. 8, it is clear that conversion of CH4, CO2 and steam at 500 °C is almost zero; although, by rising the reaction temperature, conversion of CH4, CO2, and H2O were notably increased. As an example, rising the reaction temperature from 550 to 750 °C created a conversion increase up to higher than 95% for CH4, 15% to 92% for steam and 13% to 93% for CO2. The conversion reaches to its maximum value at 800 °C. CO2 conversion is lower than CH4 in each temperature due to its consumption and production during the tri-reforming process as it was discussed in Zhang et al. (Zhang et al., 2013) and Zhou et al. ﬁndings (Zhou et al., 2011). Since increase in temperature is needed for higher conversions of CH4 and CO2, it should be considered that the reactions should take place at high temperatures; however, the coke formation must be controlled. Fig. 8. Conversion of CH4, CO2, and steam in tri-reforming reactor as a function of temperature. conversion only 9%. It should be mentioned that in this simulation, the CO2 is only injected into the reactor by the feed line. The effects of steam injection rate on the CH4 conversion are shown in Fig. 7(c). It Fig. 9. Effects of temperature and air ﬂow rate on O2 permeation ﬂux through the BSCF membranes. (a) thickness = 4.5 mm, He ﬂow rate = 60 m3/min, air ﬂow rate = 150 m3/min, (b) temperature = 800 °C, thickness = 4.5 mm, He ﬂow rate = 60 m3/min. 3.1.2. Effect of different parameters on O2 diffusion Fig. 9(a) shows the effect of temperature on the O2 permeation rate. The increase in temperature leads to the rise of O2 permeation ﬂux in the perovskite membrane. Moreover, with the decrease in the bulk penetration resistance, O2 permeation ﬂux increases. The effect of air ﬂow rate on the rate of O2 diffusion from the BaxSr1-x Co0.8Fe0.2O0.3 (BSCF as a provskite membrane) membranes is shown in Fig. 9(b). It can be seen that the O2 permeation rate has been initially raised by increasing the air ﬂow rate until it reaches to 150 m3/min, then it remains almost constant at ﬂow rates over 150 m3/min. This could be related to the Fig. 10. Comparison of (a) NOx emission rate, and (b) CO2 emission rate in conventional and proposed processes. 574 A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 involve using membrane reactors for NH3 production or thermally coupled reactors in order to use synthesis gas. References Fig. 11. Comparison of NH3 production rate in conventional and proposed processes. structural features of the membrane which would not affect the air ﬂow rate and the partial pressure of O2 in the upper side of the membrane. Therefore, it is concluded that in the airﬂow rate investigation, especially in high ﬂow rates of O2, diffusion portion can be ignored. 4. CO2 emission, NOx emission and NH3 production Fig. 10(a) shows the net amount of NOx produced in the conventional and proposed processes. The amount of NOx produced in the proposed process reaches to almost zero. The required N2 for conventional NH3 production process is supplied by air injection into the reactor. The presence of O2 in the reactor is unfavorable because of its combination with N2 which leads to NOx production. The required N2 in the proposed process is provided by air separation using a perovskite membrane and added to the H2 produced from the synthesis gas unit. This leads to a decrease in the production rate of NOx from 8220 ppm to 10 ppm. Fig. 10(b) shows the net amount of CO2 released to the atmosphere by the NH3 synthesis unit during the conventional and proposed processes. The amount of CO2 emission released to the atmosphere in the proposed process decreased from 1192 kg/h to approximately 1 kg/h. In the conventional process, amine unit and methanol reactor are associated with NH3 reactor to reuse CO2 from the synthesis gas stream, which CO2 is released after the separation of the synthesis gas stream into the atmosphere, but in the propsed process, the synthesis gas is sent to the Pd/Ag membrane and CO2 is separated. Fig. 11 shows the amount of NH3 produced in the conventional and proposed processes. The production of NH3 increased from around 25,000 kg/h to 32,000 kg/h, about 27% increase compared to the conventional process. The reason for this increase is due to the use of trireforming reactor by utilizing produced CO2 which leads to increase in the production of H2 and NH3. 5. Conclusion In this paper, the efﬁciency of NH3 synthesis unit was improved by associating a tri-reforming reactor with a membrane unit. In order to enhance the NH3 production, three ﬂuids of steam, O2, and CO2 were injected into the tri-reforming reactor. The simulation results showed that O2 and steam injection were more efﬁcient than CO2 injection. The optimum operating conditions obtained for tri-reforming reactor were 1–2 bars and 750–800 °C. It was shown that increasing the temperature from 500 °C to 750 °C increased the conversion of CH4 from zero to 95 %. The H2/CO selectivity was entirely dependent on the recycling value of separated CO2 in the reactor. The required N2 for NH3 production was provided using a perovskite membrane as well as the O2 required for the tri-reforming reactor. The future work could Amin, M.R., Sharear, S., Siddique, N., Islam, S., 2013. Simulation of NH3 synthesis. Am. J. Chem. Eng. 1, 59–64. Andersson, J., Lundgren, J., 2014. Techno-economic analysis of NH3 production via integrated biomass gasiﬁcation. Appl. Energy 130, 484–490. Araujo, A., Skogestad, S., 2008. Control structure design for the ammonia synthesis process. Comput. Chem. Eng. 32, 2920–2932. Arora, P., Hoadley, A.F.A., Mahajani, S.M., Ganesh, A., 2017. Multi-objective optimization of biomass based NH3 production - potential and perspective in different countries. J. Clean. Prod. 148, 363–374. Arora, P., Sharma, I., Hoadley, A., Mahajani, S., Ganesh, A., 2018. Remote, small-scale, ‘greener’ routes of ammonia production. J. Clean. Prod. 199, 177–192. Bicer, Y., Dincer, I., 2017. Life cycle assessment of nuclear-based hydrogen and NH3 production options: a comparative evaluation. Int. J. Hydrog. Energy 42, 21559–21570. Bicer, Y., Dincer, I., 2018a. Ammonia production. Compr. Energy Syst. 3, 41–94. Bicer, Y., Dincer, I., 2018b. Life cycle assessment of NH3 utilization in city transportation and power generation. J. Clean. Prod. 170, 1594–1601. Bicer, Y., Dincer, I., Zamﬁrescu, C., Vezina, G., Raso, F., 2016. Comparative life cycle assessment of various NH3 production methods. J. Clean. Prod. 135, 1379–1395. Bicer, Y., Dincer, I., Vezina, G., Raso, F., 2017. Impact assessment and environmental evaluation of various NH3 production processes. Environ. Manag. 59, 842–855. Damanabi, A.T., Bahadori, F., 2017. Improving GTL process by CO2 utilization in trireforming reactor and application of membranes in Fisher Tropsch reactor. J. CO2 Util. 21, 227–237. Damanabi, A.T., Bahadori, F., 2018. A new approach for hydrogen production in Claus sulfur recovery process. J. Sulfur Chem. 40, 1–12. Dincer, I., 2012. Green methods for hydrogen production. Int. J. Hydrog. Energy 37, 1954–1971. Dwivedi, A., Gudi, R., Biswas, P., 2018. Oxy-fuel combustion based enhancement of the trireforming coupled methanol production process for CO2 valorization. J. CO2 Util. 24, 376–385. Frattini, D., Cinti, G., Bidini, G., Desideri, U., Ciofﬁ, R., Jannelli, E., 2016. A system approach in energy evaluation of different renewable energies sources integration in NH3 production plants. Renew. Energy 99, 472–482. Ghadimi, A., Alaee, M.A., Behrouzifar, A., Asadi, A.A., Mohammadi, T., 2011. O2 permeation of BaxSr1−xCo0.8Fe0.2O3−δperovskite-type membrane: experimental and modeling. Desalination 270, 64–75. Gilbert, P., Alexander, S., Thornley, P., Brammer, J., 2014. Assessing economically viable carbon reductions for the production of NH3 from biomass gasiﬁcation. J. Clean. Prod. 64, 581–589. Hu, Y., An, R., Chu, Y., Tan, X., Sunarso, J., Wang, S., Liu, S., 2018. Perovskite hollow ﬁber membranes supported in a porous and catalytically active perovskite matrix for air separation. Sep. Purif. Technol. 192, 435–440. Jain, A., Miyaoka, H., Kumar, S., Ichikawa, T., Kojima, Y., 2017. A new synthesis route of ammonia production through hydrolysis of metal – nitrides. Int. J. Hydrog. Energy 42, 24897–24903. Jeremiaš, M., Pohorely, M., Bode, P., Skoblia, S., Beno, Z., Svoboda, K., 2014. Ammonia yield from gasiﬁcation of biomass and coal in ﬂuidized bed reactor. Fuel 117, 917–925. Katarzyna, Ś., Grzybek, T., Motak, M., 2017. Tri-reforming as a process of CO2 utilizaion and a novel concept of energy storage in chemical products. E3S Web of Conferences. 14, p. 02038. Lam, S.K., Suter, H., Bai, M., Walker, C., Davies, R., Mosier, A.R., Chen, D., 2018. Using urease and nitriﬁcation inhibitors to decrease ammonia and nitrous oxide emissions and improve productivity in a subtropical pasture. Sci. Total Environ. 644, 1531–1535. Lu, J., Kitamura, Y., Takisawa, K., Jiang, W., 2015. Development of a partial heating system to enhance bio-NH3 production and recovery by anaerobic digestion of N2-rich wastewater: effect of partial heating modules. Chem. Eng. J. 262, 973–979. Lu, N., Gallucci, F., Melchiori, T., Xie, D., Annaland, M.V.S., 2018. Modeling of autothermal reforming of methane in a ﬂuidized bed reactor with perovskite membranes. Chem. Eng. Process. 124, 308–318. Mazinani, S., Ramazani, R., Samsami, A., Jahanmiri, A., Van der Bruggen, B., Darvishmanesh, S., 2015. Equilibrium solubility, density, viscosity and corrosion rate of carbon dioxide in potassium lysinate solution. Fluid Phase Equilib. 396, 28–34. Mazinani, S., Ramezani, R., Darvishmanesh, S., Molelekw, G.F., Di Felice, R., Van der Bruggen, B., 2018. A ground breaking polymer blend for CO2/N2 separation. J. CO2 Util. 27, 536–546. Orrego, D.A., Junior, S.O., 2016. On the efﬁciency, exergy costs and CO2 emission cost allocation for an integrated syngas and NH3 production plant. Energy 177, 341–360. Pan, S., Chiang, P., Pan, W., Kim, H., 2018. Advances in state-of-art valorization technologies for captured CO2 toward sustainable carbon cycle. Crit. Rev. Environ. Sci. Technol. 48, 471–534. Psara, N., Annaland, M.V.S., Gallucci, F., 2015. Hydrogen safety risk assessment methodology applied to a ﬂuidized bed membrane reactor for autothermal reforming of natural gas. Int. J. Hydrog. Energy 40, 10090–10102. Rahimpour, M.R., Jamshidnejad, Z., Jokar, S.M., Karimi, G., Ghorbani, G., Mohammadi, A.H., 2012. A comparative study of three different methods for ﬂare gas recovery of Asalooye Gas Reﬁnery. J. Nat. Gas Sci. Eng. 4, 17–28. Sadeghi, M., Jafari, M., Yari, M., Mahmoudi, S.M.S., 2018. Exergoeconomic assessment and optimization of a syngas production system with a desired H2/CO ratio based on methane tri-reforming process. J. CO2 Util. 25, 283–301. A.T. Damanabi et al. / Science of the Total Environment 664 (2019) 567–575 Song, C., Pan, W., 2004. Tri-reforming of methane: a novel concept for catalytic production of industrially useful synthesis gas with desired H2/CO ratios. Catal. Today 98, 463–484. Zhang, Y., Cruz, J., Zhang, S., Lou, H.H., Benson, T.J., 2013. Process simulation and optimization of methanol production coupled to tri-reforming process. Int. J. Hydrog. Energy 38, 13617–13630. Zhang, Z., Li, Y., Zhang, W., Wang, J., Soltanian, M.R., Olabi, A.G., 2018a. Effectiveness of amino acid salt solutions in capturing CO2: a review. Renew. Sust. Energ. Rev. 98, 179–188. 575 Zhang, Z., Cai, J., Chen, F., Li, H., Zhang, W., Qi, W., 2018b. Progress in enhancement of CO2 absorption by nanoﬂuids: a mini review of mechanisms and current status. Renew. Energy 118, 527–535. Zhao, M., Li, Y., Sun, S., 2011. Analysis and optimization of two-column cryogenic process for argon recovery from hydrogen depleted NH3 purge gas. Chem. Eng. Res. Des. 89, 863–878. Zhou, L., Zhang, A., Swiderski, W., Yang, W., 2011. Blasiak Study and development of a high-temperature process of multi reformation of CH4 with CO2 for remediation of greenhouse gas. Energy 36, 5450–5459.