posted:2016-06-06
Chain grate boiler are widely used by some industry and countries, especially in Pakistan. Usually, they often use coal fuel to heating coal fired boilers. Most of our clients will ask a question how much steam produce with 1kg coal fuel before they buy chain grate boiler. Today, we will talking about this questions briefly.
|
Fuel |
Coal price |
1t/h |
2t/h |
6t/h |
8t/h |
25t/h |
35t/h |
|
4000KCal coal(kg) |
400RMB/t |
208 |
411 |
1225 |
1633 |
4342 |
5965 |
Chain grate boiler with coal fuel fired
Second, we should consider how to calculate the true cost of steam:
Knowing the correct cost of steam is an important for many reasons, and all of them have to do with improving the company’s bottom line, including:
• To properly evaluate the economics of proposed process efficiency or capacity-improvement projects; if the calculated cost is not accurate, many good energy projects may be missed or rejected, and bad projects may be approved for implementation
• To serve as a basis for optimizing the steam generation system, and minimize costs
•To ensure more effective negotiations with the utility or third party Independent Power Producers
•To properly evaluate proposed cogeneration projects. Steam is used for a variety of applications in commerce and industry:
• Process heating
• Vacuum jets
• Shaft work for mechanical drives
• Power generation
• Space heating.
In industrial manufacturing facilities, process heating accounts for an average of more than 60% of thermal energy use, predominantly in the form of steam. Process heating also accounts for a significant portion of controllable operating costs. It is one of the few areas of opportunity where management can reduce operating costs and improve profits.
The True Cost of Steam
In most companies, the reported cost of steam is the average cost of generation at a particular production rate. The total operating costs—fuel, power, water, chemical additives, labor, maintenance, depreciation, interest, and administrative overheads—are divided by the total amount of steam produced. This may be a convenient corporate financial benchmark, but is not particularly useful for managing the steam system to minimize costs. For that, we need a better method for steam cost accounting.
One of the problems is that the cost of steam depends on the generation rate, especially in complex multi-boiler multi-fuel plants that also have steam turbines. To most people, this is not intuitively obvious. In this BestPractices Steam Technical Brief, we will show how to calculate the steam cost at different process operating rates, and demonstrate through an illustrative example that the only way to do this accurately is through steam-system modeling.
Consider the simplified system shown in Figure 1, taken from an actual plant.
Typical schematic flowsheet for a simple steam system
Accurately determining steam costs is important for monitoring and managing energy use in a plant, for evaluating proposed design changes to the generation/distribution infrastructure and the process itself, and for continuing to identify competitive advantages through plant efficiency improvements. Steam costs are highly dependent on the path that steam follows in the generation and distribution system. Simulation models are simple, convenient, and reliable tools to follow these paths, calculate the correct costs, and to optimize the system. The method used for evaluating utility costs has a dramatic effect on project economics, and therefore the investment decision. Improper utility pricing can lead to bad decisions; good projects can be discarded, and bad projects can be implemented. Regrettably, this is relatively common. To avoid such mistakes, it is imperative that plant engineers and managers use appropriate methods for steam pricing, taking into account all the parameters that impact energy costs—fuel, condensate, power generation, and cooling water—when evaluating proposed projects.