Bed burning with fluid ( FBC ) is technology used to burn Solid fuel .
In its most basic form, the fuel particles are suspended in boiling fluid and boiling beds from ash and other particulate matter (sand, limestone etc.) through which air is blown to provide the oxygen required for combustion or gasification. Fast and intimate fast mixing of gases and solids encourages rapid heat transfer and chemical reactions in the bed. FBC plants are capable of burning a range of low grade solid fuels, including most types of coal and wood biomass, with high efficiency and without the need for expensive fuel preparation (eg, Destruction). In addition, for certain hot tasks, the FBC is smaller than an equivalent conventional furnace, so it may provide significant advantages over the latter in terms of cost and flexibility.
FBC reduces the number of sulfur emitted in the form SO x emissions. Lime Stone is used to precipitate sulfate during combustion, which also allows more efficient heat . Transfer from boiler to equipment used to capture heat energy (usually water tube). Heated sediments in direct contact with the tube (heating by conduction) increase efficiency. Since this allows coal plants to burn at colder temperatures, subtract NOT X is also transmitted. However, combustion at low temperatures also causes an increase in hydrocarbon emissions of hydrocarbon hydrocarbon derivatives. FBC boilers can burn fuel other than coal, and lower combustion temperatures (800 ° C / 1500 ° F) have other added benefits as well.
Benefits [ edit ]
There are two reasons for FBC’s rapid increase in combustion. First, the freedom of choice of fuel in general, not only the possibility of using combustible fuel using other technologies, is an important advantage of fluidized bed burning. The second reason, which is becoming increasingly important, is the possibility to achieve, during combustion, low emission of nitric oxide and possibly eliminate sulfur simply by using limestone as a bed material.
Fluidized bed burning evolved from attempts to find a combustion process capable of controlling pollutant emissions without external emission control (such as flue-gas scrubber). The technology burns fuel at a temperature of 1,400 to 1,700 ° F (750-900 ° C), well below the threshold at which the nitrogen oxide forms (about 2,500 ° F / 1400 ° C, nitrogen and oxygen atom in the burning air Combining to form oxide pollutants) oxidation of oxide nitrogen oxide) ;; It also avoids the problem of fusing ash associated with high combustion temperatures. The mixing action of the fluidized bed carries the exhaust gas into contact with sulfur . – ignore chemicals, such as limestone or dolomit . More than 95% of coal sulfur pollutants can be captured in the boiler by sorbent . This reduction may be less substantial than it looks, however, along with a dramatic rise in carbon emissions (monoxide?) And polyclicly aromatic hydrocarbons. [ references ]
The FBC Commercial unit operates at a competitive efficiency, the cost of conventional boiler units is less than today, and has emissions of 2 and SO 2 below the level mandated by Federal Standards. However, they have some disadvantages such as erosion of the tubes inside the boiler, the uneven distribution of temperatures caused by the clogs in the air intake in the bed, the long time to reach 48 hours in some cases.
Type [ edit ]
The FBC system corresponds to essentially two main groups, the atmospheric system (FBC) and the pressurized system (PFBC), and two small sub groups, bubbles (BFBs) and circulated fluidized beds ( CFB ).
The fluidized bed atmosphere uses limestone or dolomite to capture sulfur released by coal combustion. The air net retains the mixture of sorbent and coal combustion during combustion, converting the mixture into a suspension of red-flowing red particles such as liquid. This boiler operates at atmospheric pressure.
PFBC [ edit ]
The first generation PFBC system also uses air sorbents and jets to suspend the mixture of sorbent and coal combustion during combustion. However, the system operates at high pressure and generates high-pressure gas flow at temperatures which can drive Gas turbine . Steam generated from heat in a fluidized bed sent to wind turbine steam turbine , Creating a highly efficient combined cycle system.
Advanced PFBC [ edit ]
The 1½-generation PFBC system increases the firing temperature of the gas turbine by using natural gas in addition to the air that is laid off from the PFB burner. This mixture is burned in a topping burner to provide higher entry temperature for greater combined cycle efficiency. However, this uses natural gas , usually fuel at a price higher than coal.
- APFBC In a more advanced second-generation PFBC system, pressurized carbonizers are combined to process feed coal into gas and char fuel. PFBC burn char to generate steam and to heat combustion air for gas turbine. The fuel gas from the carbonizer burns in the topping burner associated with the gas turbine, heating the gas up to the firing temperature of the fired combustion turbine. Heat recovered from exhaust gas turbine to produce steam, used for conventional driving Steam turbine , resulting in higher overall efficiency for combined combined cycles output Power This system is also called APFBC, or circulatory circulatory pressure combination circulating fluidized-bed comboion system. The APFBC system is entirely fueled by coal.
- GFBCC. The combined cycle fluidization combined bed system, GFBCC, has a pressurized pressurized gasifier feeding fuel (PCFB) partially syngas to the combustion turbine topping gas. Waste gas turbines supply combustion air for burning fluidized-atmospheric beds that burn char from a partial gasifier PCFB.
- CHIPPS. The CHIPPS system is similar, but uses a furnace instead of a bed burner with the atmosphere. It also has a gas turbine preheater tube to increase the efficiency of the gas turbine cycle. CHIPPS stands for high performance combustion-based power system.