Sequestration process

Another group of surveys has focused on the direct modeling of some effective transport phenomena which are essential for predicting parameters that have an important role in underground gas sequestration process such as diffusivity and convection. Azin et al., in 2013, have conducted study regarding correct measurement of diffusivity coefficient [114]. 

Once the C02 is captured and compressed, it needs to be transported to the sequestration or utilization locations, unless the capture and sequestration processes are located at the same site. A C02 transportation infrastructure could be done with a rather conventional approach. On land, pipelines for long-distance C02 transport already exist. For example, a pipeline system more than 500 mi. long connects C02 fields in Southern Colorado to oil fields in West Texas. The C02 is purchased at about 15/ton for tertiary oil recovery. The cost of C02 transportation is a function of distance, whereas the costs of pipeline construction vary significantly by region (Doctor et al., 1997). The construction and operation of pipelines for ocean would be quite different from land-based pipelines. Generally, C02 is transported at supercritical pressures (-2000 psi). If C02 is sequestered at geological formations, the transferred C02 may require additional compression at the injection site depending on the specifics of the reservoir (Doctor et al., 1997). 

Mineral carbonation is a new and, consequently, less studied method of sequestration. Mineral resources are plentiful for storing all the carbon that could ever be released in the consumption of fossil fuels. This sequestration process offers a safe and permanent method of C02 disposal, since there is almost no possibility of accidental release of C02 from the disposal site as C02 is chemically incorporated into the mineral and immobilized. Furthermore, the reactions that bind C02 to the mineral are exothermic in nature leading to the formation of thermodynamically stable carbonate forms (IPCC, 2005). 

A unified gas hydrate kinetic model (developed at ARC) coupled with a thermal reservoir simulator (CMG STARS) was applied to simulate the dynamics of CH4 production and C02 sequestration processes in the Mallik geological zones. The kinetic model contains two mass transfer equations one equation transfers gas and water into hydrate, and a decomposition equation transfers hydrate into gas and water (Uddin etal. 2008a). 

Using hydrogen to produce electrical energy from fossil fuels in large centralised plants will contribute positively to achieving important reductions of C02 emissions, if this is combined with C02 capture and sequestration processes. Such plants will also help to increase the diversification of resources, since a variety of fossil feedstocks can be used, including resources such as coal and waste that otherwise cause major impacts on the environment, as well as biomass. 

Total concentrations of chemicals in the compartment of exposure are considered of limited relevance because, due to sorption and sequestration processes, often only a small fraction of the total amount is available for uptake by organisms. Properties of the chemical and of the environment determine sorption, chemical speciation, and bioavailability. Information on chemical concentrations therefore is much more... 

Under certain experimental conditions, AEA accumulation into the cell is not saturable (Glaser et al. 2003), whereas, in the absence of a cell monolayer, the plastic ware used in studies of AEA cellular uptake can mimic the AEA sequestration process in terms of temperature sensitivity (Fowler et al. 2004). 

The overall sequestration process involves four steps ... 

Intensive use of the herbicide paraquat has resulted in the evolution of resistance in various weed species. Intensive research on the resistance mechanisms was mainly carried out with resistant biotypes from Hordeum spp. and Conyza spp., and altered distribution of the herbicide in the resistant weeds was suggested as the cause - or at least the partial cause - of resistance. In resistant Conyza canadensis it was supposed that a paraquat inducible protein may function by carrying paraquat to a metabolically inactive compartment, either the cell wall or the vacuole. This sequestration process would prevent the herbicide from getting in sufficient amounts into the chloroplasts as the cellular site of paraquat action. Inhibitors of membrane transport systems, e.g., N,N-dicyclohexylcarbodii-mide (DCCD), caused a delay in the recovery of photosynthetic functions of the paraquat-resistant biotype, when given after the herbicide. These transport inhibitor experiments supported the involvement of a membrane transporter in paraquat resistance [75]. 

Synonyms NaeDTPMP Properties Amber liq. m.w. 705 Uses Deflocculant, sequestrant, scale inhibitor for cooling water treatment, detergents, peroxide bleach stabilization, l l cleaners, geothermal, oil field applies. deflocculant, sequestrant, process additive for paper, textiles, and metals industrial and commercial formulations for cleaning various substrates cement modifier (retards concrete setting times)... 

In an effort to accurately predict the thermodynamic and transport properties of CO2 in mixtures with other components, typically found in the carbon capture and sequestration process, both molecular simulation... 

However, recent results did not support the chemical protection of C bound to iron and aluminium complexes [38]. Some studies have suggested that it is the surface area of the mineral particles that can explain the slow C mineralization [39 2]. In previous studies one has shown that the carbon and nitrogen content is also related to the specific surface area [11, 17]. High specific surface areas will increase the possible adsorption sites for chemical species and certainly participate in the sequestration mechanism but the peculiar (fractal) structure of the allophane aggregate should play a role in the sequestration process. The mesopore protection hypothesis proposes that carbon is trapped in the tortuous porosity of the soils because the organic matter is protected from enzymatic degradation by sequestration within the mineral mesopores (2-50 nm diameter) [40, 42-44]. 

Uses Encrustation aid, sequestrant, process aid for detergents (powd. laundry, liq. laundry, hard surf., auto dish liq., auto dish powd., auto dish rinse), textiles (scours, rinse aids, dyebaths, water softeners), pigments (mining, pigment slurries)... 

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