Equipment design boilers

What exactly do we mean by the term shortcut equipment design method Here is an example. Two rules are given for determining the thickness in inches of copper boiler level float balls ... 

With twin-flue design boilers, it is usual to have completely separate gas passes through the boiler with twin wetback chambers. It is then possible to operate the boiler on one flue only, which effectively doubles its turndown ratio. For example, a boiler rated at 20,000 kg/h F and A100°C may reasonably be expected to operate down to 2500 kg/h F and A100°C on oil or gas providing suitable combustion equipment and control is incorporated. If prolonged periods of single-flue operation become necessary. 

Primarily it is the demand for MU and its quality (by which we mean the level of natural and introduced contaminants present in the water), coupled with the boiler and support equipment design and materials of construction under consideration, that collectively provide for a unique set of potential waterside problems in any individual steam system cycle. 

These various problems may arise under several different circumstances. For example, difficulties may result from consistently poor operational control of the boiler plant or from enforced operating conditions that fall outside generally accepted procedures. Alternatively, problems may stem from malfunctioning equipment, from equipment design flaws, from inadequate water treatment programs, or even as a result of poor interpretation of monitored results and bad water treatment advice. 

The amount of hardness deposits in steam is a function of entrainment of water, as well as the TDS of the boiler feedwater. A well-designed boiler, then, often is equipped with a mesh-type demister pad to remove entrainment from the produced steam. 

The problems with the commercial use of coal are usually due to the mineral matter present in the coal. Over 80% of the coal used in the United States is burned in boilers to generate steam for electric power production. In the combustion process, the mineral matter is released and in a few seconds traverses the furnace and subsequent parts on the way to the smokestack. If most of the mineral matter has a relatively high ash fusion temperature, this material, termed flyash, moves through the furnace parts to some equipment designed to remove the fine particles. If the ash fusion temperature is not relatively high then the small particles... 

Economics Thanks to the high efficiency of the process and equipment design, the total energy consumption (evaluated as feeds + fuel + steam import from package boiler and steam export to urea) is lower than 6.5 Gcal/metric ton of produced ammonia. 

This process involves staging the combustion by diverting 5%-20% of combustion air from the burners and injecting above the main combustion zone and can reduce the NOx emissions by 20%-60% depending on the initial nitrogen oxide levels in the boiler, fuel combustion equipment design, and fuel type. The amount of unbumed carbon is on the order of 35%-50%. 

Advance amounts required by vendors are generally 15-25 % of cost of machinery (in case the cost of machinery is in the range of about 50-70 % of total cost of project depending on the complexity of technology). Vendors may ask for greater advance amount if costly materials of construction (stainless steel, titanium, or special alloys) are required for fabrication, pressure vessels are to be supplied or equipment designs are complicated such as special reactors or boilers. 

Handling equipment and boilers, designed for the nominal specification of a singles coal, may become inefficient or troublesome in operation when degradation has occurred. 

A well-designed boiler, then, often is equipped with a mesh-type demister pad to remove entrainment from the produced steam. 

Several developments are being pursued to utilize coal directly, ie, automation of controls, coal and ash handling equipment for smaller stoker and pulverized coal-fired units, design of packaged boiler units, and pollution control equipment. In the cement industry coal firing has been used, because the sulfur oxides react with some of the lime to make calcium sulfate in an acceptable amount. 

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