Gas utilization

Heavy residues are not always converted. The use of low sulfur light crude and crudes having a reduced ultimate residue (higher ratio of gasoline + distillates/vacuum residue) as well as natural gas utilization has been intensified. 

The state-of-the-art i -Si H films (Table 3) are deposited at the rate of 1—3 A/s with the gas utilization rate on the order of 15%. Larger gas utilization rates, hence larger deposition rates, usually result in inferior properties than those indicated in Table 3. Increasing the deposition rate by merely increasing the power leads to dust formation. The use of higher excitation frequency can lead to deposition rates in excess of 15 A/s and still give relatively good film properties (7). 

Heat is transferred by direct contact with solids that have been preheated by combustion gases. The process is a cycle of alternate heating and reactingperiods. The Wulf process for acetylene by pyrolysis of natural gas utilizes a heated brick checker work on a 4-min cycle of heating and reacting. The temperature play is 15°C (59°F), peak temperature is 1,200°C (2,192°F), residence time is 0.1 s of wmich 0.03 s is near the peak (Faith, Keyes, and Clark, Industrial Chemicals, vol. 27, Wiley, 1975). 

Natural gas is transmitted in pipelines first across the country under high pressure m transcontinental pipe lines to local gas utility companies. The gas utility company reduces the pressure and distributes the gas through underground mains, and again reduces pressure from the street main into the home. 

Electric utilities have historically been franchise monopolies, vertically integi ated from power production through transmission, distribution, and customer service with no competition from other electric utilities. However, in many parts of the countiy, electric and gas utilities do compete. Rates charged by these utilities were determined in a regulatoiy proceeding Electric utilities proposed rates that compensated them for their expenses and allowed them to earn a reasonable return state regulatoiy commissions reviewed and approved the proposals. 

This is the primary legislation concerning the gas industry in the UK, together with certain section of the Gas Act 1972 and the Gas Act 1965 which have not been repealed. The Gas Act does not have great relevance to safety aspects of gas utilization. However, specific regulations can be published under this enabling Act. 

Install a check valve or equivalent if the utilization equipment might induce a backpressure or the gas utilization equipment is connected to a source of oxygen or compressed air. 

A Regulatory Framework and Incentives for Gas Utilization. Public Policy Journal Note No. 279. Washington, DC World Bank. 

Increasing reactant gas utilization or decreasing inlet concentration results in decreased cell performance due to increased concentration polarization and Nernst losses. These effects are related to the partial pressures of reactant gases and are considered below. 

The voltage of MCFCs varies with the composition of the reactant gases. The effect of reactant gas partial pressure, however, is somewhat difficult to analyze. One reason involves the water gas shift reaction at the anode due to the presence of CO. The other reason is related to the consumption of both CO2 and O2 at the cathode. Data (55,64,65,66) show that increasing the reactant gas utilization generally decreases cell performance. 

Figure 6-8 Influence of Reactant Gas Utilization on the Average Cell Voltage of an...

The above discussion implies that MCFCs should be operated at low reactant gas utilizations to maintain voltage levels, but doing this means inefficient fuel use. As with other fuel cell types, a compromise must be made to optimize overall performance. Typical utilizations are 75 to 85% of the fuel. 

Sulfur It is now well established that sulfur compounds in low ppm (parts per million) concentrations in fuel gas are detrimental to MCFCs (74,75,76,77,78). The tolerance of MCFCs to sulfur compounds (74) is strongly dependent on temperature, pressure, gas composition, cell components, and system operation (i.e., recycle, venting, gas cleanup). The principal sulfur compound that has an adverse effect on cell performance is H2S. At atmospheric pressure and high gas utilization (-75%), <10 ppm H2S in the fuel can be tolerated at the anode (tolerance level depends on anode gas composition and partial pressure of H2), and <1 ppm SO2 is acceptable in the oxidant (74). These concentration limits increase when the temperature increases, but they decrease at increasing pressures. 

A reference fuel gas utilized in experimental SOFCs has had a composition 67% H2/22%... 

Present Status of Methane Gas Utilization as a Rural Fuel in Korea. 

Addresses fuel gas piping systems in and between buildings. The scope includes piping between the outlet of the consumers meter and the outlet of the first pressure-containing valve upstream of the gas utilization device. 

NATURALHY - project aims to define the technical and socio-economic conditions to inject hydrogen in natural gas using the existing infrastructure in a transition to the Hj economy. 48 partners are involved including major EU gas utilities with a budget of 11 million. 

The Austrian gas utility companies Energie AC Oberosterreich, Wienstrom, ESTAC and SAFE are testing PEM and SOFC residential fuel cell power plants from Sulzer Hexis and Vaillant companies. 

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