Gas quality

The end product specification of a process may be defined by a customer (e.g. gas quality), by transport requirements (e.g. pipeline corrosion protection), or by storage considerations (e.g. pour point). Product specifications normally do not change, and one may be expected to deliver within narrow tolerances, though specification can be subject to negotiation with the customer, for example In gas contracts. 

Gas processing facilities generally work best at between 10 and 100 bar. At low pressure, vessels have to be large to operate effectively, whereas at higher pressures facilities can be smaller but vessel walls and piping systems must be thicker. Optimum recovery of heavy hydrocarbons is achieved between 20 bar and 40 bar. Long distance pipeline pressures may reach 150 bar and reinjection pressure can be as high as 700 bar. The gas process line will reflect gas quality and pressure as well as delivery specifications. 

Product quality is not limited to oil and gas quality certain effluent streams will also have to meet a legal specification. For example, in disposal of oil in water, the legislation in many offshore areas demands less than 40 ppm (parts per million) of oil in water for disposal into the sea. In the UK, oil production platforms are allowed to flare gas up to a legal limit. 

The gas quality feeding the dry faee seal should be elean and dry. Due to the possibility of eondensation of the proeess gas in the seal eavity, it was deeided to use a seal gas heater. The heater eontrol was set to provide warm gas at 15°C above the dew point to ensure no eondensate entered the seal eavity. Also, a dual filter in series with 5 and 2 p filtration elements was ehosen to provide an ideal sealing environment and maintain the optimum performanee of the seal. To reduee the risk of seal damage during reverse rotation of the turboexpander, programming logie was set to open the eompressor bypass valve whenever a shutdown impulse was initiated. 

Contamination from Seai Gas Suppiy. Contamination from the seal gas supply oeeurs when the sealing gas is not properly treated upstream of the dry gas seal. Gas seal manufaeturers have stringent requirements for seal gas quality. Typieally, the sealing gas must be dry and filtered of partieles 3 mieron and larger. Filters are normally provided in the gas seal system to meet this requirement. 

Homogeneous flow may be described using volumetric gas quality. 

Table 3 shows some physicochemical properties used as international GA quality parameters, for example moisture, total ash content, volatile matter and internal energy, with reference to gums taken from Acacia Senegal species in Sudan (FAO, 1990, Larson Bromley, 1991). The physicochemical properties of GA may vary depending on the origin and age of trees, the exudation time, the storage type, and climate. The moisture content facilitates the solubility of GA carbohydrate hydrophilic and hydrophobic proteins. The total ash content is used to determine the critical levels of foreign matter, insoluble matter in... 

The C02 gas quality has significant impact on the capture cost by this technology, and uncertainties on the future regulatory requirements of C02 quality for its transport and storage has influence on the process configuration of the oxy-combustion plant, gas cleaning unit performance, overall C02 recovery capacity and on the energy requirements for C02 compression and purification. 

Main Gas Quality Requirements for Different Hydrogen Gas Applications... 

Dayton, D. C. Ratcliff, M. Bain, R., Fuel Cell Integration—A Study of the Impacts of Gas Quality and Impurities. NREL, Golden, CO, 2001. 

A 2-value smaller than 1 means that there is an excess of fuel in the mixture. In this case the air/fuel mixture is called rich. If more air is in the mixture than needed for a complete fuel combustion (2 > 1) the term lean mixture is used. Ideally the combustion is complete at 2 = 1. Real fuel cannot be combusted without an increase in CO and soot at 2-values smaller than 1.05. Due to changing operation conditions, for example a soiled burner, wear of the nozzle or leaky flaps, change of gas quality or changes of temperature and air pressure in the ambient atmosphere, the air/fuel ratio and thus flue gas composition can change over time. In order to minimize the risk of intoxication (see also chapter 5333), explosion and pollution real (uncontrolled) fuel burners are adjusted to operate far beyond this limit in the excess (lean mixture) region. However, unfortunately effi-... 

Additionally gas quality sensors are required, in order to allow natural gas from a variety of sources to be utilized as efficiently as possible. 

Also, several types of gas quality sensors can be utilized, such as ... 

For WTW analysis, it is a sufficiently accurate assumption, that natural gas mainly consists of methane (CFI4). Compressed natural gas is also referred to as CNG . Natural gas is extracted, processed, transported and distributed via pipeline to the filling stations, where it is compressed to about 25 MPa. Natural gas sources may vary for different countries. Depending on the source (natural gas quality) and the transport distance (e.g., 4000 km or even 7000 km from Russia, depending on the relevant gas fields) the auxiliary energy needs or energy losses, and hence the GHG-relevant emissions can vary. For the calculation of the energy requirement and GHG emissions for the supply of natural gas, a transport distance of 4000 km is assumed. 

The gasifier fuel gas quality is an important issue for the RP development. The effect of the fuel gas composition has been modeled. The modeling showed that the potential hydrogen production efficiency is strongly dependent on the combustion products/syngas (CP/SG) ratio [(C02+Hj0)/(C0+H2) = CP/SG] of the fuel gas. 

The calorific value of this gas is too high for direct use as town gas (470-500 Btu/standard cubic foot in the United Kingdom) and too low for SNG, However, by removing the CO> the calorific value is increased to about 870 Btu/standard cubic foot, which is useful for enriching lean gas (e.g. from an Imperial Chemical Industries (IC1) naphtha reformer) to town gas quality. Long has suggested that by enriching this gas with LPG (liquefied petroleum gas) a satisfactory SNG may be obtained. 

The overall issue of gas quality within the Azerbaijan transportation system will require policy development prior to decisions on infrastructure investment. 

The operator of the upstream network, the state owned company Gassco AS, is awarded certain powers under Section 66 of the PR. The operator s responsibilities include operation of the network, maintenance and maintenance planning, and co-ordination of processes for further development of the network.25 The operator shall also co-ordinate gas quality nominations at inlets and outlets and may under special circumstances even issue binding instructions to operators of production facilities in order to avoid operational disturbances or gas quality problems.26... 

A single operator is also favorable in the case of network failures (for example during a compressor shutdown) as efficient coordination is required in order to secure the integrity of infrastructure as well as minimizing overall losses due to flow disturbances and gas quality deterioration. 

On the construction of a reaction container from a glass cylinder, sealed above and below by PVC plates with gas qualities and O-rings,... 

The LTS catalyst is protected by a guard bed, formerly loaded with ZnO, but nowadays usually with LTS catalyst [621]. Changing the guard bed more frequently prolongs the service life of the main LTS catalyst bed. Without a guard bed the lifetime is normally 2-4 years, depending on gas quality. With an upstream guard bed,... 

Conceptually, the process can run in self-sufficient heating mode. In this case, overall gas calorific requirement may need a small net export or import as the product gas quality... 

Dayton, D., Ratcliff, M., Bain, R. (2001). Fuel cell integration - a study of the impacts of gas quality and impurities. Report NREL/MP-510-30298, National Renewable Energy Lab., Golden CO. 

Key points in the present research programme are optimisation of the gasifier with respect to thermal efficiency and gas quality determination of operating limits (throughput, temperature, material characteristics) prevention of tar and acids formation. 

Effect of fuel size and process temperature on fuel gas quality from CFB gasification of biomass... 

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