CO2 recovery system

Although CO2 is comparatively innocuous in small quantities and is relatively cheap, it cannot be discharged in unlimited quantities and it must be largely recovered in a well-designed process. 

2 Discontinuous recovery of CO2. This is required whenever the contents of a batch extractor are discharged or whenever the contents of an activated carbon or ion resin adsorber require changing. In order to minimise the downtime associated with the above operations, the expansion should take place as rapidly as possible, but subject to the following restraints. 

Rapid expansion can damage the product, because the CO2 within the solid matrix cannot then escape fast enough to prevent substantial excess pressure from developing at points within the structure of the material being extracted. The structure then ruptures producing an undesirably fine powder. 

The higher mass flow rates associated with rapid expansion entail comparatively high investment costs for the piping system and condenser. 

In practice between 15 and 25 minutes are allowed depending on vessel size (about 50% of this volume will be occupied by CO2, the rest being occupied by coffee or adsorbent as the case may be), for discharging CO2 by means of a compressor. 

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The choice of a specific CO2 removal system depends on the overall ammonia plant design and process integration. Important considerations include CO2 sHp required, CO2 partial pressure in the synthesis gas, presence or lack of sulfur, process energy demands, investment cost, availabiUty of solvent, and CO2 recovery requirements. Carbon dioxide is normally recovered for use in the manufacture of urea, in the carbonated beverage industry, or for enhanced oil recovery by miscible flooding. 

A 250 kilowatt system is planned for a site in Norway. The system will be operated by Norske Shell to demonstrate that CO2 can be economically recovered. The CO2 recovery technology is being developed by Shell Hydrogen. The CO2 could be sequestered in underground reservoirs or could be used for special applications such as fish farms or agricultural greenhouses. The test system will be sited at a fish hatchery. The system is expected to begin operation in early 2003. 

However the coal system inevitably has a high CO2 emission which would contribute global warming. The problem "CO2 emission" in Fig. 1 will be technologically able to be removed by CO2 recovery disposal. But the total consumption of fuel resource would be rather accelerated (Fig. 2, -AEi) that we cannot find any sustainable prospect over there. 

Figure 2 Fossil fuel system in addition of CO2 recovery disposal -AF. 1 process energy for CO2 recovery.

Coal system (Fig. 2) can join with a solar hydrogen system which is very difficult in the global transportation, at the processes of CO2 recovery and fuel synthesis (Fig. 3). 

If we succeed to increase a percentage of CO2 recovery from synthetic fuel use, finally, we may approach to perfect Carbon-recycle system, without an abrupt change. The ultimate scheme is shown in Fig. 5. 

The problem (3). A chemical process in general, 100% yield of recovery will never achieved. In the case of CO2 recovery from flue gas, it becomes very difficult when higher than 95%, considering the process energy consumption. Even in future, about 5% of carbon should be helped from outside of the system. However, this percentage of carbon sources will be able to supply from the municipal wastes and industrial refuse in future society. 

For the CO2 recovery from fossil based power stations an additional primary energy input is required, producing supplementary CO2 emissions. The overall energy efficiency of the methanol vectors and the CO2 balance of the fossil based recovery process will be compared to the CO2 recovery from the atmosphere and to the conventional crude oil-gasoline system. 

Kinetic analysis of CO2 recovery from flue gas by an ecotechnological system... 

Lee K-H, Yeon S-H, Sea B, Park Y-I. HoUow fiber membrane contactor hybrid system for CO2 recovery. Stud Surf Sci Catal 2004 153(Carbon Dioxide Utilization for Global Sustainability) 423-428. Elsevier BV. 

Carbon dioxide analysers, based on heat capacity, electrical conductivity or partial pressure measurements, but especially on IR light absorption, are therefore used at various points in industrial processes. Carbon monoxide and dioxide are the species most commonly analysed for by the last of the above-mentioned detection techniques, which is also employed in a variety of processes [6], namely (a) control of the hydrogenation of plant oils in order to avoid production of unwanted trans isomers (b) measurement of sugars and CO2 In soft drinks (c) measurement of moisture (d) determination of CO2 In Industrial environments (e) determination of isocyanates In the production of polyurethane (f) determination of methane In argon from nuclear plants (g) control of the efficiency of solvent clean-up and recovery systems. 

Supercritical fluid extraction with CO2 has shown that a wide variety of solutes can be extracted from ILs with the solutes being recovered without IL contamination [9,45,46]. This is accomplished as CO2 dissolves in the solvent mixture to facilitate extraction, but the IL does not dissolve in CO2, so pure product can be recovered. In addition, IL/CO2 biphasic solutions have been used for a variety of homogeneously catalyzed reactions, as well as for extraction and recovery of organic solutes. Interestingly, the CO2/IL system remains two distinct phases, even under pressures up to 400 bar [46]. 

WGS reactors with the membrane reactors. A combination of membrane designs such as hydrogen-selective sweep membranes for bulk hydrogen recovery and C02-selective membranes for the cold end of the process to support the CO2 liquefacticMi system has been shown to improve the IGCC s commercial aspects. Future developments on membrane technology are required to improve the short lifetime, selectivity and permeability coefficients of these systems. 

The H2S - CO2 gas is at 38°C and 1.72 bara. Ninety-five percent of the H2S is converted to sulfur. The sulfur recovery system is to be installed in Houston, Texas. 

Sasaki A., Matsumoto S., Fujitsuka M., Shinoki T., Tanaka T., Ohtsuki J., 1993. CO2 recovery in molten carbonate fuel cell system by pressure swing adsorption, JEEE Trans. 

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