Liquid fuels requirements

Liquid fuels require atomization and treatment to inhibit sodium and vanadium content. Liquid fuels can drastically reduce the life of a unit if not properly treated. A typical fuel system is shown in Figure 4-7. The effect of fuels on gas turbines and the details of types of fuel handling systems is given in Chapter 12. 

The heating of a fuel affects the overall size of the fuel system. Generally, fuel heating is a more important concern in connection with gaseous fuels, since liquid fuels all come from petroleum crude and show narrow heating-value variations. Gaseous fuels, on the other hand, can vary from llOOBtu/ft (41,000 KJ/m ) for natural gas to (11,184 KJ/m ) or below for process gas. The fuel system will of necessity have to be larger for the process gas, since more is required for the same temperature rise. 

The majority of today s turbines arc fueled wth natural gas or No. 2 distillate oil. Recently there has been increased interest in the burning of nonstandard liquid fuel oils or applications where fuel treatment is desirable. Gas turbines have been engineered to accommodate a wide spectrum of fuels. Over the years, units have been equipped to burn liquid fuels, including naphtha various grades of distillate, crude oils, and residual oils and blended, coal-derived liquids. Many of these nonstandard fuels require special provisions. For example, light fuels like naphtha require modifications Co the fuel handling system to address high volatility and poor lubricity properties. 

Sub-Section 3 enables an owner to serve a notice on the local authority requiring them to take the measurements that he would be required to obtain under Section 7 of the 1956 Act. The ratings of such furnaces shall be less than one ton per hour of solid fuel other than pulverized fuel or liquid or gaseous-fuelled furnaces with a rating of less than 28 million BTUs. 

Liquid fuels require their own pumps, flow control, nozzles, and mixing systems. Many gas turbines are available... 

C4-C6 Alkanes are highly volatile and, hence, of low value as a transportation fuel or a fuel additive. Since high-quality fuels require the generation of liquid hydrocarbons, the fructose-derived HMF and acetone have been converted into their mono- (C9) and bis-aldols (C15), which on Si02-Al203/Pt-catalyzed dehy-dration/hydrogenation produce C9-C15 alkanes (Scheme 2.8). A major drawback of this approach, however, is the fact that HMF, de facto, is a fructose-derived product, and is not producible in an industrially viable price frame at present vide infra. Section 2.3.2). 

The clean and efficient utilization of synthetic liquid fuels requires a detailed understanding of the chemical, physical, and combustion characteristics of these fuels as they burn in utility and industrial combustion equipment. We have... 

Many effective control schemes have been established over the years for individual chemical units (Shinskey, 1988), For example, a tubular reactor usually requires control of inlet temperature. High-temperature endothermic reactions typically have a control system to adjust the fuel flowrate to a furnace supplying energy to the reactor. Crystallizers require manipulation of refrigeration load to control temperatui e. Oxygen concentration in the stack gas from a furnace is controlled to prevent excess fuel usage. Liquid solvent feed flow to an absorber is controlled as some ratio to the gas feed. We deal with the control of various unit operations in Chaps. 4 through 7. 

Based on a depreciation of 5 years and 10% interest rate a cost -benefit analysis is included in table 2. In the same table a cost - benefit analysis is given in case the corn miller would be able to replace the liquid fuel required, by gas from corn cobs. Then the corn mill is enlarged with a suitable gasifier for 2000 Tsh. The economic advantages of the gasifier for the corn miller are evident in view of the profit increase. 

The current ethanol supply is, in the large part, derived from starch. Nevertheless, vast amounts of agricultural residues and other lignocellulosic biomass can serve as the feedstock for ethanol production. Theoretically, enough ethanol can be produced from cellulosic biomass to meet most of the liquid fuel requirements in the US. The expanded utilization of lignocellulosic biomass for ethanol production can also free starchy crops for food and other uses. In addition, less carbon dioxide emission can be realized if more ethanol can be produced from lignocellulosic biomass and if the market for ethanol as a transportation fuel can be expanded beyond the current level. 

With ever increasing requirements for clean transportation fuels and liquid hydrocarbon supplies, there is an opportunity to produce significant quantities of synthetic ultra-clean fuels that are essentially sulfur-free. These synthetic fuels can be produced from natural gas, coal, petroleum coke, biomass, and other non-traditional hydrocarbon sources. Most of these products are fungible and compatible with current products and distribution infrastructure and can be produced at costs competitive with conventional crude oil-derived products under certain market conditions. 

In 1973, prior to the first energy crisis, New Zealand imported virtually all its liquid fuel requirements in the form of oil or its products. At this time such imports represented about 60 percent of New Zealand s primary energy requirements and cost less than 5 percent of the country s export earnings. After the first oil shock the cost of liquid fuels jumped to between 20 and 30 percent of export earnings and thereby severely weakened the economy. 

An additional challenge to the use of fuel cells for automobiles is response time. Currently, fuel cells have a response time of 15 seconds from 10 percent power to 90 percent. In order to be viable, this response time must drop to 1 second. Because they require liquid water to operate, a further challenge is to operate fuel cells in subfreezing temperatures. In addition, the current cost per kilowatt-hour for fuel cells must be reduced from 300 down to 45. 

Combination burners are typically freestanding burners that can fire both gas and liquid fuels. The liquids that are commonly burned are fuels such as No. 2 fuel oil (diesel) or No. 6 fuel oil. These burners also require connections for the medium used to atomize the liquid fuel, which is typically steam or air. The burner can be used to fire only gas, only liquid, or some combination of the two. Figure 18.12 is a rendering of an up-fired combination burner. 

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