Utilities steam

A simple direct-flame incinerator may be a refractory-lined furnace arranged for good mixing and fitted with a burner. Such an incinerator is low in capital cost and suitable for periodic or batch burning of a process purge gas during plant shutdown. However, such an incinerator in continuous service on other than a very small vent would have extremely high fuel operating cost. In these cases, sufficient auxiHary fuel must be provided to completely heat the incinerator gas to the ignition temperature and this heat can be further utilized. Steam can be generated if there is a need for process steam. If steam is not needed, moderate to large size incinerators have a heat exchanger between the incoming gases and the hot combustion products to preheat make-up air. Because of the temperatures involved, heat-transfer surfaces are generally of alloy constmction or ceramic materials. The latter can be damaged by thermal shock if sudden step changes in operation occur, whereas alloys may be attacked by corrosive gases such as halogens and sulfates if present.  [c.59]

In gold and silver production, lime is used to control the pH in both heap and vat leaching processes which utilize sodium cyanide solutions. Lime helps maintain the pH of the cyanide solution between 10 and 11, thereby maximizing gold recovery and preventing the formation of dangerous hydrogen cyanide gas. Because the United States is now one of the world s leading gold producers, this development has spurred lime usage in the western states and also in South Carolina.  [c.178]

Fossil-Fuel-Fired Steam Generators for Which Construction Commenced after August 17, 1971 Electric Utility Steam Generating Units for Which Construction Commenced after September 18, 1978  [c.2156]

Utility Steam Generators. 27-40  [c.2356]

Utility Steam Generators  [c.2394]

Operating Expense — Utility Steam Turbine Driven Air Blower Motor Driven Air Blower One Stage Expander Driven Air Blower Two Stage Expander Driven Air Blower  [c.215]

Other industries of interest are (1) the manufacturing of spices and flavorings, which may use activated carbon filters to remove odors from their exhaust stream (2) the tanning industry, which uses afterburners or activated carbon for odor removal and wet scrubbers for dust removal and (3) glue and rendering plants, which utilize sodium hypochlorite scrubbers or afterburners to control odorous emissions.  [c.513]

The simplest plant is a topping refinery that prepares feedstocks for petrochemical manufacture or for production of industrial fuels. It consists of tankage, a distillation unit, recovery facilities for gases and light hydrocarbons, and supporting utilities (steam, power, and water-treatment plants). The range of products is increased by the addition of hydrotreating and reforming units comprising a hydroskimming refinery, which can produce desulfurized distillate fuels and high octane gasoline. About half of the production is fuel oil.  [c.286]

Refrigerant temperatures greater than 32°F suggest the steam jet or lithium bromide absorption system. Between 30°F and —40°F, the ammonia-water absorption or a mechanical compression system is indicated. At less than —40°F, a mechanical compression is used, except in special desiccant situations. The economics of temperature level selection will depend on utility (steam, power) costs at the point of installation and the type of pay-out required, because in some tonnage ranges, the various systems are competitive based on first costs.  [c.289]

Steam Utilization Steam Tables (metric SI units)  [c.340]

If the total heat consumed is from an external utility (e.g., mains steam), then a high efficiency is desirable, even perhaps at the expense of a high capital cost. However, if the heat consumed is by recovery from elsewhere in the process, as is discussed in Chap. 15, then comparison on the basis of dryer efficiency becomes less meaningful.  [c.91]

An alternative inappropriate use of utilities involves heating of some of the cold streams below the pinch by steam. Below the pinch, cooling water is needed to satisfy the enthalpy imbalance. Figure  [c.168]

In design, the same rules must be obeyed around a utility pinch as around a process pinch. Heat should not be transferred across it by process-to-process transfer, and there should be no inappropriate use of utilities. In Fig. 6.13a this means that the only utility to be used above the utility pinch is steam generation and only cooling water below. In Fig. 6.136 this means that the only utility to be used above  [c.173]

Find a way to overcome the constraint while still maintaining the areas. This is often possible by using indirect heat transfer between the two areas. The simplest option is via the existing utility system. For example, rather than have a direct match between two streams, one can perhaps generate steam to be fed into the steam mains and the other use steam from the same mains. The utility system then acts as a buffer between the two areas. Another possibility might be to use a heat transfer medium such as a hot oil which circulates between the two streams being matched. To maintain operational independence, a standby heater and cooler supplied by utilities is needed in the hot oil circuit such that if either area is not operational, utilities could substitute heat recovery for short periods.  [c.184]

Utilities are varied. The most common hot utility is steam. It is usually available at several levels. High-temperature heating duties require furnace flue gas or a hot oil circuit. Cold utilities might be refrigeration, cooling water, air cooling, furnace air preheating, boiler feedwater preheating, or even steam generation at higher temperatures.  [c.185]

Figure 6.25a shows the same grand composite curve with two levels of saturated steam used as a hot utility. The steam system in Fig. 6.25a shows the low-pressure steam being desuperheated by injection of boiler feedwater after pressure reduction to maintain saturated conditions. Figure 6.256 shows again the same grand composite curve but with hot oil used as a hot utility.  [c.186]

A more complex utility is combined heat and power (or cogeneration). Here, the heat rejected hy a heat engine such as a steam turbine, gas turbine, or diesel engine is used as the hot utility.  [c.193]

Now let us take a closer look at the two most commonly used heat engines (steam and gas turbines) to see whether they achieve this efficiency in practice. To make a quantitative assessment of any combined heat and power scheme, the grand composite curve should be used and the heat engine exhaust treated like any other utility.  [c.194]

Figure 6.33 shows a steam turbine integrated with the process above the pinch. Heat Qhp is taken into the process from high-pressure steam. The balance of the hot utility demand Qlp is taken  [c.195]

Different utility options such as furnaces, gas turbines, and different steam levels can be assessed more easily and with greater confidence knowing the capital cost implications for the heat exchanger network.  [c.233]

The outer layer of the onion diagram in Fig. 1.6 (the utility system) produces utility waste. The utility waste is composed of the products of fuel combustion, waste from the production of boiler feedwater for steam generation, etc. However, the design of the utility system is closely tied together with the design of the heat exchanger network. Hence, in practice, we should consider the two outer layers as being the source of utility waste.  [c.274]

The principal sources of utility waste are associated with hot utilities (including cogeneration) and cold utilities. Furnaces, steam boilers, gas turbines, and diesel engines all produce waste as gaseous c bustion products. These combustion products contain carbon  [c.274]

Utility systems as sources of waste. The principal sources of utility waste are associated with hot utilities (including cogeneration systems) and cold utilities. Furnaces, steam boilers, gas turbines, and diesel engines all produce waste from products of combustion. The principal problem here is the emission of carbon dioxide, oxides of sulfur and nitrogen, and particulates (metal oxides, unbumt  [c.290]

Energy efficiency of the process. If the process requires a furnace or steam boiler to provide a hot utility, then any excessive use of the hot utility will produce excessive utility waste through excessive generation of CO2, NO, SO, particulates, etc. Improved heat recovery will reduce the overall demand for utilities and hence reduce utility waste.  [c.291]

Fuel switch. The choice of fuel used in furnaces and steam boilers has a major effect on the gaseous utility waste from products of combustion. For example, a switch from coal to natural gas in a steam boiler can lead to a reduction in carbon dioxide emissions of typically 40 percent for the same heat released. This results from the lower carbon content of natural gas. In addition, it is likely that a switch from coal to natural gas also will lead to a considerable reduction in both SO, and NO, emissions, as we shall discuss later.  [c.293]

Waste from steam systems. If steam is used as a hot utility, then inefficiencies in the steam system itself cause utility waste. Figure 10.9 shows a schematic representation of a steam system. Raw water from a river or other source is fed to the steam system. This is  [c.293]

In Chap. 6 it was discussed how the use of multiple utilities can give rise to multiple pinches. For example, the process from Fig. 6.2 could have used either a single hot utility or two steam levels, as shown in Fig. 6.26a. The targeting indicated that instead of using 7.5 MW of high-pressure steam at 240°C, 3 MW of this could be substituted with low-pressure steam at 180°C. Where the low-pressure steam touches the grand composite curve in Fig. 6.26a results in a utility pinch. Figure 16.17a shows the grid diagram when two steam levels are used with the utility pinch dividing the process into three parts.  [c.381]

Following the pinch rules, there should be no heat transfer across either the process pinch or the utility pinch by process-to-process heat exchange. Also, there must be no use of inappropriate utilities. This means that above the utility pinch in Fig. 16.17a, high-pressure steam should be used and no low-pressure steam or cooling water. Between the utility pinch and the process pinch, low-pressure steam should be used and no high-pressure steam or cooling water. Below the process pinch in Fig. 16.17, only cooling water should be used. The appropriate utility streams have been included with the process streams in Fig. 16.17a.  [c.381]

Given a network structure, it is possible to identify loops and paths for it, as discussed in Chap. 7. Within the context of optimization, it is only necessary to consider those paths which connect two different utilities. This could be a path from steam to cooling water or a path from high-pressure steam used as a hot utility to low-pressure steam also used as a hot utility. These paths between two different utilities will be designated utility paths. Loops and utility paths both provide degrees of freedom in the optimization.  [c.390]

Utilities (fuel, steam, electricity, cooling water, process water, compressed air, inert gases, etc.)  [c.406]

A viable electrocatalyst operating with minimal polarization for the direct electrochemical oxidation of methanol at low temperature would strongly enhance the competitive position of fuel ceU systems for transportation appHcations. Fuel ceUs that directiy oxidize CH OH would eliminate the need for an external reformer in fuel ceU systems resulting in a less complex, more lightweight system occupying less volume and having lower cost. Improvement in the performance of PFFCs for transportation appHcations, which operate close to ambient temperatures and utilize steam-reformed CH OH, would be a more CO-tolerant anode electrocatalyst. Such an electrocatalyst would reduce the need to pretreat the steam-reformed CH OH to lower the CO content in the anode fuel gas. Platinum—mthenium alloys show encouraging performance for the direct oxidation of methanol.  [c.586]

Bottoms and three side-cut strippers remove light ends from products and may utilize steam or reboilers. In Fig. 13-92 a reboiled stripper is utilized on the light distillate, which is the largest side cut withdrawn. Steam-stripping rates in side-cut strippers and at the bottom of the atmospheric column may vary from 0.45 to 4.5 kg (1 to 10 lb) of steam per barrel of stripped liquid, depending on the fraction of stripper feea hquid that is vaporizea.  [c.1330]

Figure 1.5 Hyperbolic towers cooling condenser water in a utility station. [Fig. 38.10, The Nalco Water Handbook, 1st ed. (1979), reprinted with permission from McGraw-Hill, Inc., Courtesy of The Marley Company.] Figure 1.5 Hyperbolic towers cooling condenser water in a utility station. [Fig. 38.10, The Nalco Water Handbook, 1st ed. (1979), reprinted with permission from McGraw-Hill, Inc., Courtesy of The Marley Company.]
Fossil fuel and electric utility steam generatof" l>73 MW (>250 million BTU/hr) input] (264 KJ/hr) Incinerators  [c.412]

It is interesting to note that Kulstad and Malmsten have utilized yet another method for introducing nitrogen into the crown precursors. They utilize sodium azide in DMSO to displace halogen from triethylene glycol dichloride. The bis-azide is then reduced using hydrogen sulfide in ethanol.  [c.161]

One interesting metabolic theory is that glucose and lipid levels in the blood affect each other s metabolism. Glucose metabolism is disturbed in sugar diabetes and some of the toxic effects of the resulting metabolic imbalance is believed to be due to enhanced oxidation of fatty acids as an alternate food. It is theorized that inhibitors of fatty acid oxidation could reverse the cycle in favor of glucose utilization. Sodium palmoxirate (19) was selected as a potential oral antidiabetic agent of a new type based upon this premise. Its synthesis begins by alkylating  [c.3]

Pressure relieving devices in process plants for process and utility steam systems must conform to the requirements of ASME [1] Par. UG-131b. This is not necessarily satisfactory to meet the ASME Power Boiler Code for applications on power generating equipment.  [c.426]

The temperatures or enthalpy change for the streams (and hence their slope) cannot he changed, but the relative position of the two streams can be changed by moving them horizontally relative to each other. This is possible because the reference enthalpy for the hot stream can be changed independently from the reference enthalpy for the cold stream. Figure 6.16 shows the same two streams moved to a different relative position such that AT ,in is now 20°C. The amount of overlap between the streams is reduced (and hence heat recovery is reduced) to 10 MW. More of the cold stream extends beyond the start of the hot stream, and hence the amount of steam is increased to 4 MW. Also, more of the hot stream extends beyond the start of the cold stream, increasing the cooling water demand to 2 MW. Thus this approach of plotting a hot and a cold stream on the same temperature-enthalpy axis can determine hot and cold utility for a given value of Let us now extend this approach to many hot  [c.161]

Where the cold composite curve extends beyond the start of the hot composite curve in Fig. 6.5a, heat recovery is not possible, and the cold composite curve must be supplied with an external hot utility such as steam. This represents the target for hot utility (Q niin)- For this problem, with ATn,in = 10°C, Qnmin 7.5 MW. Where the hot composite curve extends beyond the start of the cold composite curve in Fig. 6.5a, heat recovery is again not possible, and the hot composite curve must be supplied with an external cold utility such as cooling water. This represents the target for cold utility (Qcmin)- For this problem, with AT in = 10°C, Qcmm = 10-0 MW.  [c.165]

Analogous effects are caused by the inappropriate use of utilities. Utilities are appropriate if they are necessary to satisfy the enthalpy imbalance in that part of the process. Above the pinch in Fig. 6.7a, steam is needed to satisfy the enthalpy imbalance. Figure 6.86 illustrates what happens if inappropriate use of utilities is made and some cooling water is used to cool hot streams above the pinch, say, XP. To satisfy the enthalpy imbalance above the pinch, an import of (Q mjj,+XP) is needed from steam. Overall, (Qcmin+AP) of cooling water is used.  [c.168]

In addition, the decrease in driving forces in Fig. 12.1 caused by the process changes also affects the potential for using multiple utilities. For example, as the driving forces above the pinch become smaller, the potential to switch duty from high-pressure to low-pressure steam, as discussed in Sec. 6.6, decreases. Process changes are competing with better choices of utility levels, heat engines, and heat pumps for available spare driving forces. Each time either a process change or a different choice of utilities is suggested, the capital/energy tradeoff should be readjusted. If multiple utilities are used, the optimization of the capital/energy tradeoff is not straightforward, since each pinch (process and utility) can have its own value of ATnim- The optimization thus becomes multidimensional.  [c.323]

See pages that mention the term Utilities steam : [c.4]    [c.6]    [c.23]    [c.88]    [c.160]    [c.173]    [c.174]    [c.382]    [c.385]   
Health, safety and accident management in the chemical process industries (2002) -- [ c.156 ]