Sequential supplementary firing in natural gas combined cycle with carbon capture: A technology option for Mexico for low-carbon electricity generation and CO<inf>2</inf> enhanced oil recovery

Combined cycle gas turbine power plants with sequential supplementary firing in the heat recovery steam generator could be an attractive alternative for markets with access to competitive natural gas prices, with an emphasis on capital cost reduction, and where supply of carbon dioxide for Enhanced Oil Recovery (EOR) is important. Sequential combustion makes use of the excess oxygen in gas turbine exhaust gas to generate additional CO2, but, unlike in conventional supplementary firing, allows keeping gas temperatures in the heat recovery steam generator below 820 °C, avoiding a step change in capital costs. It marginally decreases relative energy requirements for solvent regeneration and amine degradation. Power plant models integrated with capture and compression process models of Sequential Supplementary Firing Combined Cycle (SSFCC) gas-fired units show that the efficiency penalty is 8.2% points LHV compared to a conventional natural gas combined cycle power plant with the same capture technology. The marginal thermal efficiency of natural gas firing in the heat recovery steam generator can increase with supercritical steam generation to reduce the efficiency penalty to 5.7% points LHV. Although the efficiency is lower than the conventional configuration, the increment in the power output of the combined steam cycle leads a reduction of the number of gas turbines, at a similar power output to that of a conventional natural gas combined cycle. This has a positive impact on the number of absorbers and the capital costs of the post combustion capture plant by reducing the total volume of flue gas by half on a normalised basis. The relative reduction of overall capital costs is, respectively, 15.3% and 9.1% for the subcritical and the supercritical combined cycle configurations with capture compared to a conventional configuration. For a gas price of $2/MMBTU, the Total Revenue Requirement (TRR) - a metric combining levelised cost of electricity and revenue from EOR - of subcritical and supercritical sequential supplementary firing is consistently lower than that of a conventional NGCC by, respectively, 2.2 and 5.7$/MWh at 0 $/t CO2 and by 4.9 and 6.7$/MWh at $50/t CO2. At a gas price of$4/MMBTU and $6/MMBTU, the TRR of a subcritical configuration is consistently lower for any carbon selling price higher than 2.5$/t CO2 and 37 $/t CO2 respectively

The potential of decarbonising rice and wheat by incorporating carbon capture, utilisation and storage into fertiliser production

This paper aims to evaluate the reduction on greenhouse gas emissions in rice and wheat and their supply chains by incorporating carbon capture, utilisation, and storage into fertiliser production mainly from ammonia process, which is the section of fertiliser that produces the most carbon dioxide. Greenhouse gas emissions of these grains without carbon capture, utilisation and storage are provided from the results of life cycle assessment in the literatures. After that, a carbon dioxide emission from fertiliser production is quantified. The alternative considered for utilisation is enhanced oil recovery and it is compared with conventional way of oil production. The effect of carbon capture, utilisation, and storage in greenhouse gas reduction are presented in term of rice and wheat’s supply chains to make people conscious about the use and optimisation of food. The reduction of greenhouse gas is around 6-7% in rice supply chain e.g. rice milk, spoons of uncooked rice and 14-16% in wheat supply chain e.g. pasta, one slice of bread. Although the alternative with carbon dioxide storage demonstrates marginally higher greenhouse gas reduction, enhanced oil recovery may offer economic incentive from additional oil production that could reduce the cost of rice and wheat

Techno‐environmental analysis of the use of green hydrogen for cogeneration from the gasification of wood and fuel cell

This paper aims to evaluate the use of wood biomass in a gasifier integrated with a fuel cell system as a low carbon technology. Experimental information of the wood is provided by the literature. The syngas is purified by using pressure swing adsorption (PSA) in order to obtain H2 with 99.99% purity. Using 132 kg/h of wood, it is possible to generate 10.57 kg/h of H2 that is used in a tubular solid oxide fuel cell (TSOFC). Then, the TSOFC generates 197.92 kW. The heat generated in the fuel cell produces 60 kg/h of steam that is needed in the gasifier. The net efficiency of the integrated system considering only the electric power generated in the TSOFC is 27.2%, which is lower than a gas turbine with the same capacity where the efficiency is around 33.1%. It is concluded that there is great potential for cogeneration with low carbon emission by using wood biomass in rural areas of developing countries e.g., with a carbon intensity of 98.35 kgCO2/MWh when compared with those of natural gas combined cycle (NGCC) without and with CO2 capture i.e., 331 kgCO2/MWh and 40 kgCO2/MWh, respectively. This is an alternative technology for places where biomass is abundant and where it is difficult to get electricity from the grid due to limits in geographical location

Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is improved by up to 3.27%. Additionally, the exergy destruction using TDP can be reduced in the evaporator and condenser. The highest exergy efficiency in the evaporator is 96.9%, an improvement of 62% in comparison with that of the conventional ORC, i.e., 59.9%. Thus, the small-scale solar ORC system using TDP is more promising for household application

Situación del mercado internacional de commodities agroalimentarios en los albores del siglo XXI

LIBRO: LA CRISIS ALIMENTARIA Y LA SALUD EN MÉXICO. EDITADO POR CASTELLANO EDITORES Y UNIVERSIDAD AUTÓNOMA DEL ESTADO DE MÉXICOEn el comienzo del presente siglo, el periodo de precios bajos en los mercados internacionales de commodities agroalimentarios se terminó, luego se entró a uno de fluctuaciones más frecuentes en dichos precios. El objetivo de la investigación es analizar la situación del mercado internacional de commodities agroalimentarias durante la primera década del siglo XXI, en específico el maíz, la soya y el trigo. Por ello se abordan el papel relevante del sector agroalimentario en una economía y una sociedad, además, los cambios que han existido en los agroalimentos durante el siglo XX. La metodología de apoyo es el estudio de la estructura de mercado de dichos productos agrícolas. Los resultados permiten entender la situación de concentración del mercado así como la situación de la oferta y la demanda internacionales. Se concluye que es un mercado en oligopolio y que existen factores de diversa índole que inciden en éste, desde lo demográfico hasta lo ambiental