Costs of carbon dioxide

Another EOR approach to reducing the viscosity of oil in the reservoir is ntiscible flooding— the injection of fluids that mix with the oil under reservoir conditions. Such fluids include carbon dioxide, light hydrocarbons, and ititrogen. Supply and cost of carbon dioxide are often more favorable than for other injectants. Extensive research and field testing have established the techiucal viability of miscible flooding, and a nnmber of commercial carbon dioxide miscible flooding projects are in operation. 

The Selectoxo unit can also help in a grass root plant by maintaining carbon dioxide/ammonia production ratios which is favorable for full conversion of ammonia to urea. The economics of this option are to be considered against the extra cost of carbon dioxide production by other means (either from the flue gas of the primary reformer or through back burning of extra synthesis gas)202. 

After allowance is made for ethane flaring and the carbon dioxide emissions, the CLOSED system produces approximately 0.6 tonne of carbon dioxide per tonne of olefin. Using the same cost of carbon dioxide the result is that production cost is lifted from 869 to 890/tonne. 

In the chemical production complex in the lower Mississippi River corridor shown in Fig. 3, there are about 150 plants that consume 1.0 quad (lO BTU/yr) of energy and generate about 215 million pounds of pollutants per year. There is a carbon dioxide pipeline that connects plants. Currently, there is approximately an excess 1.0 million metric tons of high-purity carbon dioxide per year from ammonia production that is being vented to the atmosphere. The cost of carbon dioxide as a raw material is essentially the pumping cost to a plant, about US 2-3 per metric ton. ... 

Since the cost of the mobile phase often represents more than half of the total cost of the separation (except the lower cost of carbon dioxide in supercritical fluid chromatography, SFC), it is worthwhile to minimize the solvent consumption and also to increase the concentration of the product in the eluted fractions. Regeneration of the mobile phase is an economical choice at high solvent consumption rates. Regeneration may include distillation of the used mobile phase followed by adjustment of the mobile phase composition if necessary. 

Figure 15-19. Estimated costs of carbon dioxide removal for a C02-fk>od EOR project-low utility cost case Goddin, 19821. Reproduced with permission Rom ProceetRngs of the 61st Annual Convention of the GPA, copyright 1982,6as Processors Association...

The control of carbon dioxide emission from burning fossil fuels in power plants or other industries has been suggested as being possible with different methods, of which sequestration (i.e., collecting CO2 and injecting it to the depth of the seas) has been much talked about recently. Besides of the obvious cost and technical difficulties, this would only store, not dispose of, CO2 (although natural processes in the seas eventually can form carbonates, albeit only over very long periods of time). 

Only about 10% of the total urea production is used for amino resins, which thus appear to have a secure source of low cost raw material. Urea is made by the reaction of carbon dioxide and ammonia at high temperature and pressure to yield a mixture of urea and ammonium carbamate the latter is recycled. 

Much more carbon dioxide is generated daily than is recovered (44). The decision whether or not to recover by-product carbon dioxide often depends on the distance and cost of transportation between the carbon dioxide producer and consumer. For example, it has become profitable to recover more and more carbon dioxide from C02-rich natural gas weUs in Texas as the use of carbon dioxide in secondary oil recovery has increased. The production levels for enhanced oil recovery are generally not reported because of the captive nature of the appHcation. 

Although the continuous-countercurrent type of operation has found limited application in the removal of gaseous pollutants from process streams (Tor example, the removal of carbon dioxide and sulfur compounds such as hydrogen sulfide and carbonyl sulfide), by far the most common type of operation presently in use is the fixed-bed adsorber. The relatively high cost of continuously transporting solid particles as required in steady-state operations makes fixed-bed adsorption an attractive, economical alternative. If intermittent or batch operation is practical, a simple one-bed system, cycling alternately between the adsorption and regeneration phases, 1 suffice. 

At a pressure of 30 bar and with excess steam the fractional conversion of methane in the reformer is reasonably satisfactory. The high pressure of 30 bar will favour the removal of carbon dioxide, following the shift reaction CO + H2O CO2 + H2, and reduce the cost of compressing the purified hydrogen to a value, typically in the range 50-200 bar, required for ammonia synthesis. 

Zhang, Z. and Folmer, H. (1998). Economic modelling approaches to cost estimates for the control of carbon dioxide emissions. Energy Economics, 20 (1), 101-120. 

The conversion of carbon dioxide into carbon feedstock for the manufacture of fuels and chemicals is an important area of research. It has the advantage of lower cost, due to the abundant supply of CO, and has the environmental benefit of... 

For recycling to improve the performance of an MCFC network, it must provide benefits that outweigh its inherent disadvantages. If carbon dioxide is not separated from the anode-anode recycle, the concentration of carbon dioxide in the anode is increased. This reduces the Nemst potential. The Nemst potential is similarly reduced by the anode-cathode recycle if steam is not condensed out, since recycled steam dilutes reactant concentrations in the oxidant. In addition, part of the power generated by the network is consumed by the equipment necessary to circulate the recycle streams. Such circulation equipment, along with the additional ducting required by recycling, also increases the capital cost of the MCFC network. 

---