Chakib Bouallou

CO2 Abatement Through a Methanol Production Process

A CO2 to methanol process was simulated and optimized with Aspen Plus. The CO2 comes from the capture by chemical absorption from the flue gas of a coal thermoelectric plant. The thermoelectric plant provides electrical energy for CO2 capture and the methanol plant. Hydrogen is produced from the electrolysis of water using a carbon-free source of electricity. The methanol plant provides 46 % of the steam necessary for CO 2 capture, which remarkably reduces the impact of CO2 recovery on the performance of the thermoelectric plant. The CO2 balance showed that it is possible to abate a large amount of CO2 from the production of methanol if carbon-free hydrogen is available.

On the possibilities of producing hydrogen by high temperature electrolysis of water steam supplied from biomass or waste incineration units.

The incineration of biomass and waste is considered to produce water steam, which then would feed the High Temperature Electrolysis (HTE) process in order to produce hydrogen. For these energy sources, in a French context, results show that water steam production cost could be in a range of 0.02 to 0.06 euros per steam kilogram. Potentially 78 million vehicles could be fed with hydrogen coming from the steam produced by the incineration of the currently nonvalorised biomass and domestic waste. Furthermore, for each energy source the optimized hydrogen production cost estimation has been performed, including investment and operation costs.

Storage and restoring the electricity of renewable energies by coupling with natural gas grid

The renewable energy network is constantly expanding due to the increasing world demand to reduce greenhouse gases emissions and to maintain an adequate energy supply level. However, renewable energy systems are facing two major difficulties: storing electrical power when consumption is quite below the production potential, and delivering electricity when high consumption peaks appear. This paper aimed to simulate an alternative process that can store and restore renewable electricity by forming and reforming the natural gas (methane). The specificity of this process is sharply interesting, since it uses methane as a means of storage instead of electricity, taking advantage of the high energy density of methane. The gas transformation will be coupled to a reversible solid oxide cells (RSOC) working at high temperature (1073 K). The simulation results showed that the installation can deliver electricity with 36.4% of energy efficiency, while electricity storage is performed with an efficiency of 92.4%. The best advantage lies on the process carbon balance: storing then restoring 1 MWh of electricity will only emits 69 g of additional CO2 in the air.

Hydrogen production by high temperature electrolysis coupled with an EPR, SFR or HTR: techno-economic study and coupling possibilities

Hydrogen production by high temperature electrolysis coupled with three nuclear reactors (the European pressurised reactor, the sodium-cooled fast reactor and the very high temperature reactor) was studied in terms of perspectives and hydrogen production costs. Firstly, we present the features of producing water steam by using the three nuclear reactors. Secondly, we present the hydrogen production cost for the HTE process coupled with each type of nuclear reactor. These costs are optimal values of the hydrogen production cost for the mentioned couplings and they were estimated by using a genetic algorithm procedure. High potentiality for these HTE couplings was assessed and contrary to steam source temperatures, the electricity price appeared to be a key parameter for low hydrogen production costs.

Technico-economic feasability study of CO2 capture, transport and geo-sequestration part 2: A case study for france

Publisher Summary This chapter presents the results of technical and economic studies with various organizations in order to evaluate the future production cost of electricity from coal integrated gasification combine cycle (IGCC) power plants with CO2 capture and sequestration and the resulting cost per ton of CO2 avoided. It aims at performing a realistic approach of the energy penalty due to the integration of CO2 capture in IGCC power plants as well as a realistic evaluation of the transport and storage costs taking into account the topography for the CO2-transport pipeline and the reservoir characteristics for the CO2 storage. The two power plants are supposed to be located close to the French cities of Nantes and Metz. This corresponds to a traditional localization for coal power plants in France, but does not necessarily constitute the optimal situation with respect to the storage zones of CO2 and to the constraints of fuel supply. Concerning the CO2 capture, six physical and chemical absorption processes were modeled with the aspen plus TM software.

Technico-economical feasibility study of CO2 capture, transportation and geo-sequestration: A case study for France part 1: Comparison of the CO2 capture options in IGCC system

Publisher Summary The removal of CO2 from gas streams can be achieved by a number of separation techniques including absorption into a liquid solvent, adsorption onto a solid, cryogenic separation, and permeation through membranes. Among these techniques absorption into a liquid solvent is the most suitable process for a high volume of synthesis gas streams. This chapter is devoted to the energy assessment of carbon dioxide removal in an existing Integrated Gasification Combined Cycle (IGCC) plant based on an oxygen blown entrained flow gasifier operating at 27 bar, removal of acid gas (H2S) in a MDEA unit, and a 53% efficiency combined cycle. A carbon dioxide separation process conveniently integrated in a pre-combustion separation is chosen in order to take advantage of the high pressure of the gas. In the first step six appropriate CO2 removal systems are selected from existing processes in industrial area. In the second step, simulations are performed for the six CO2 separation processes, using the Aspen Plus™ software. In the third step three processes are selected and integrated, as realistically as possible, to the IGCC. Finally, energy consumption is analyzed and overall efficiency of the IGCC with CO2 capture is evaluated.

Relationship Between Ph and Carbonation Ratio To measure CO2 Capture Efficiency by Nh3 Solvent

This paper presents an established relationship between the pH of ammonia solution and its carbonation ratio (α). The aim of this correlation is to track the amount of CO2 absorbed or the amount of CO2 released from ammonia solvent. Furthermore, this paper studies the evolution of density and viscosity of ammonia solution with the carbonation ratio because those physical properties can significantly affect liquid side mass transfer coefficient. Experiments have been carried out in a thermoregulated Lewis-type cell reactor and the measures have been done using three concentrations of ammonia (3, 5 and 7 wt %) and temperatures (293, 303 and 313 K). Results show that the estimated function has a high correlation coefficient which indicates a relationship between variables. All results show a linear correlation between viscosity and carbonation ratio, and between density and carbonation ratio.

Influence of Cell Support and Operating Parameters on the Competitiveness of High-Temperature Electrolysis Process

This work focuses on hydrogen production by high-temperature electrolysis and the influence of operating parameters for cathode- or electrolyte-supported cells, used to build the electrolyzer, on the process competitiveness. The rigorous modeling of the electrical and thermal behavior of planar cells was performed and integrated into our program to estimate the hydrogen production cost, accounting process investment, and operation costs. Results show that the exothermal mode seems more competitive than the endothermal mode. Electrolyte-supported cells could allow lower degradation of cells at lower current densities, which would drive down the hydrogen production cost.

Carbon Dioxide Absorption by Ammonia Intensified with Membrane Contactors

Membrane gas absorption technology is a promising alternative for carbon dioxide (CO2) removal from post combustion coal-fired flue gases. This study examines an alternative which consists in absorbing CO2 by ammonia aqueous solution in a membrane contactor to improve the capture processes and to intensify the gas-liquid transfer. Absorption measurements through a membrane contactor have been made. The influence of the material nature constituting the membrane and operating parameters on the capture efficiency has been studied. The results have shown that it is possible to capture CO2 from ammonia through a membrane with capture efficiency greater than 90 %. The membrane limits ammonia losses but does not eliminate it.