CO2 capture processes

The example CO2 capture process, shown in Figure 8 as an Aspen Plus EO model representation, is part of an ammonia plant. Designed to scrub CO2 from ammonia synthesis gas, it includes an absorber and two solution regeneration columns, one stripping the rich, C02 laden solution leaving the absorber to semilean concentration of absorbed CO2, and the other cleaning the solution even further to lean solution... 

Puertollano (Spain) 1998 335 Amine based technology [14] Petroleum coke CO2 capture process started in 2010, Siemens entrained-flow gasifier. Siemens V 94.3 gas turbine and overall plant efficiency of 40% without CCS... 

THAHRA is designed for the assessment of solvents for application in high pressure CO2 capture processes. Intercooling of the solvent in the absorber column is able to increase solvent capacity when using reactive solvents. Within the operating window of THAH, one is able to mimic the treatment of different feeds. These include shifted syngas for pre-combustion, typically 30 bar, 40%-60% CO2-H2, as well as natural gas for pipe line and LNG, typically 45 bar, 20%-80% CO2-CH4. The maximum feed flow is 5 Nm /hr, with a liquid flow of up to 25 kg/hr. The solvent inventory is approximately 4.5 1. Due to the small liquid inventory, non-commercially available solvents can easily be tested. 

Combinations of in-line measurement techniques with multivariate modelling show promising properties for nse as real-time monitoring applications of the liqnid composition in acid gas absorption processes. Both spectroscopic and non-spectroscopic analytical techniques can be nsed. Althongh the first developments were mostly aimed at predicting CO2 and amine concentrations in post-combustion CO2 capture processes, recent developments are also directing into applications involving acid gas removal from natural gas and the use of solvents that inclnde mixtures of two active components. 

In summary, porous carbon-based materials for CO2 capture have experienced rapid development in the last several decades and will continue to blossom. The requirements of CO2 captures vary a lot depending on different processes, namely post-combustion (low pressure, predominantly CO2/N2 separation), pre-combustion (high pressure, predominantly CO2/H2 separation) capture and natural gas sweetening (predominantly CO2/CH4 separation). Thus, various kinds of new carbon materials with defined textural properties as well as tailored surface chemistry have been synthesized for a specific CO2 capture process. Another advantage lies... 

Despite the importance of the carbonation reaction for the CO2 capture process, far fewer studies can be found in the literature on this matter than for the kinetics of the calcination reaction. Furthermore, there is still little consensus on the values of the kinetic constant, the reaction order and the activation energy. 

Clodic and Younes [11,12] have developed a cryogenic CO2 capture process, in which CO2 is desublimated as a solid onto surfaces of heat exchangers, which are cooled by... 

Soundararajan, R. (2011) Efficiency loss analysis for oxy-combustion CO2 capture process, Norwegian University of Science and Technology - NTNU, Department of Energy and Process Engineering, Trondheim, Norway. 

In particular, the high cyclic capacity of the sorbent is one of the key characteristics. The higher the capacity, the more CO2 can be adsorbed per m reactor volume and the less steam for sorbent regeneration is needed reducing the primary energy consumption per ton of CO2 captured. Lifetime and specific sorbent cost are the other two key parameters predominantly affecting the operational cost of the CO2 capture process. 

If the product is not registered in LCA databases, estimations from similar processes can be used or tools calculating LCA metrics on the basis of the molecular structure of the product Pr. The Finechem tool [55] is a unique, state-of-the-art tool of this kind. A more detailed appHcation of this approach is presented in Case Study 1 for the solvent-based CO2 capture process. 

In the following sections three case studies are presented where, among other LCA aspects, some of the LCI issues discussed previously are higUighted. Case Study 1 refers to solvent-based postcombustion CO2 capture processes. Case Study 2 refers to lignoceUulosic biorefmeries, and Case Study 3 refers to the poly(methyl methacrylate) recycling process. 

In principle, aU these aspects related with the solvent selection will have an impact on the outcome of the LCA metrics of the various alternatives. Fig. 13.2 presents a generic flowsheet for the solvent-based postcombustion CO2 capture processes, illustrating also the main concerns from an LCA point of view. If the LCA scope is to screen solvents for postcombustion CO2 capture without performing process simulations (i.e., in a very early phase of process design, where perhaps the number of solvent molecules to be screened is immense, for instance, in computer-aided molecular design [CAMD] of solvent molecules [68]), the potential solvents should be characterized based on properties that would indicate their expected performance in the capture process (e.g., the standard flowsheet of Fig. 13.2). These properties can be thermodynamic in nature (e.g., solubility parameters between CO2 and the solvent, solvent heat of vaporization. 

Figure 13.2 Generic flowsheet for the solvent-based postcombustion CO2 capture processes including the main life cycle assessment-related issues.

Some of these aspects have been further analyzed in practical appHcations such as those described in the case studies of this chapter. In the first case study, it is demonstrated how screening potential solvents for postcombustion CO2 capture requires short-cut models for estimating the cradle-to-gate environmental impact of solvent production to make up for the degraded solvent during the CO2 capture process. When only a few... 

The CO2 emissions and the possible reduction in its rate from a distributed highly efficient hydrogen production system based on a membrane reformer was estimated from the actual operation test results and data from the first 40 Nm /h-class MRF. The CO2 emissions and possible reduction rate in the 40 Nm /h-class MRF were calculated by assuming that only CO2 in the off-gas was captured by liquefaction process. The material balance of the MRF with CO2 capture process at a rated load is shown by flow diagrams in Fig. 12.10. 

For the CO2 capture process, there are no commercial costs available because no full-scale plant has ever been built. For this reason, the equipment costs of the amine scrubbing section are determined from a BUA, as reported for the membrane case. As already stated, the assumed costs are estimated for a NOAK plant. The results are summarized in Table 14.7. 

Aspen Technology, Inc. Aspen plus model of the CO2 capture process by DEPG, corporate white paper. 2008. 

Nord LO, Anantharaman R, BoUand O Design and offtdesign analyses of a pre-combustion CO2 capture process in a natural gas combined cycle power plant, Int J Greenh Gas Con 3 385-392, 2009. 

In this section, we provide a rational analysis of perovskite materials for membrane design in view of high-temperature CO2 capture applications. Our purpose is to establish structure-property relationships for identifying the main formulations offering potentials for separation imder different scenarios. To address a proper technical integration of perovskite membranes into CO2 capture processes, the following key elements have to be addressed ... 

Development of a hydrogen mixed conducting membrane based CO2 capture process, in Carbon Dioxide Capture for Storage in Deep Geologic Formations (eds D.C. Thomas and S.M. Benson), Elsevier, Oxford, pp. 273-290. 

Chao [21] and Chao et al. [20, 22, 23] made a three-fluid model for a binary particle system with an interstitial gas to simulate particle segregation due to size and weight differences between the two particle types. The first part of the work considered a cold flow study of a binary particle mixture. Later, Chao [21] and Chao et al. [24] made a three-fluid model for a reactive binary particle system with a multi-component interstitial gas. The process investigated was sorption-enhanced steam methane reforming (SE-SMR) which is steam methane reforming (SMR) and a gas-solid adsorption reaction CO2 capture process. 

Recently, Fang et al. [25] and Rout and Jakobsen [66] extended the basic two-zone model for simulating non-isothermal CO2 capture processes by including the corresponding differential heat balances in terms of temperature. Moreover, Rout and Jakobsen [66] did also include transient terms in the model in order to enable simulations of the dynamic SE-SMR process. 

H. Shi, Z. Liang, T. Serna, A. Naami, P. Usubharatana, R. Idem, C. Saiwan and P. Tontiwachwuthikul, Part 5a Solvent Chemistry NMR Anatysis and Studies for Amine-C02-H20 Systems with Vapor-Liquid Equilibrium Modeling for CO2 Capture Processes, Carbon Manage., 2012, 3,185. 

To avoid major modifications of the power plant, the optimal position of a CO2 capture process seems to be in between the flue gas desulfurization unit (FGD) and the stack. Particulate matter as well as SO and NO concentrations are reduced to a large extent, which lowers the requirements regarding chemical resistance and reduces the risk of plugging. To quantify the flue gas condition subsequent to the FGD unit, a model of a state of the art hard coal fired power plant was developed and implemented in Aspen Plus . The considered power plant features a thermal duty of 1210 MW and a net thermal efficiency of 45% (based on lower heating value of the feedstock). 

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