Description
Production line option and
investment budgetary estimate of desulfurization gypsum powder with
annual capacity of *0,**0 tons
â… Current situation & utilization of FGD
gypsum
Desulfurization gypsum also
named as FGD (flue gas desulfurization) gypsum, sulfur gypsum. It
is industrial byproduct derived from desulfurization treatment of
flue gas generated by the burning of sulfide (coal).
The SO2 in the atmosphere has
been increasing with the development of industry, increase of coal
burning. The SO2 discharge value of China is up to 2.*7 million
tons in ***5. Since then, China becomes the largest SO2 discharge
country in the world. It has dramatic impact on our environment,
like air pollution, acid rain. For China, it is very urgently to
control the discharge value of SO2. According to government
regulation, all of the power plants with over *0,**0MW should equip
desulfurization machine. This regulation applies to operated &
under construction power plants since ***0.
According to the preliminary
statistics, the total capacity is more than 2,**0 MW for FGD gypsum
powder production line, which has put into operation or will put
into operation. **0MW has started in capacity. 3,**0MW has planned
in total capacity. In ***0, the total capacity of FGD units will be
up to *0,**0—*0,**0MW on coal fire plants of China. That is to say,
it will produce FGD gypsum 8,**0,**0 tons each year with purity
over *5%.
For traditional power plant,
flue gas desulfurization is most popular and most efficient
technology for So*-control project. At present, it is the sole
commercialized and scaled desulfurization technique in the world.
The technology of flue gas desulfurization can be classified wet
method, dry method and semidry method according to the feature of
process. The wet method is most popular, and gains *0% market
share. The proportion is *0% in Germany, *8% in Japan, *2% in
United States. Lime/limestone—gypsum method is most popular in wet
method. What is more, it is most mature technology on
desulfurization in the world.
FGD gypsum is one kind of
gypsum, which has same basis (CaSo4·2H2O) and
similar chemical property compared with natural gypsum. As
industrial byproduct, it has the same features as other kinds of
chemical gypsum, like more free water, incompact fine grain and
impurities. The impurities are almost inorganic and insoluble
material, which almost has no influence on gypsum. For improving
efficiency of flue gas desulfurization, the high technical
requirements on the content and fineness ofCaO in lime
stone powder ensure the stability of chemical composition for FGD
gypsum. Therefore, FGD gypsum is easiest among the application of
all kinds of chemical gypsum. What is more, its purity is high (the
content of CaSO4·2H2O is up
to *5—*5%). It is an appropriate raw material for producing
construction gypsum powder. The obtained gypsum product is high on
performance.
It follows that FGD gypsum will
be raw material with cheap price, good quality, high purify for
gypsum processing industry under suitable craft, technology and
equipment condition.
â…¡ The brief introduction of production
process
Normally FGD gypsum generated by power
plantwetdesulphurizationcontains
over *0% free water. Thinking about the perfect experience on
producing construction gypsum powder by FGD gypsum, we adopt
two-step method on calcining construction gypsum powder. It is
pre-drying raw gypsum, and then calcining in calciner. The details
as follow:
Loading machine delivers raw materials from
storage yard to feeding hoper. Belt conveyor delivers it after
measure to rotary dryer for dehydrating free water. (The hot source
is coal-fired calciner). Collected by the material collector, then
hoisting equipment put it to the calciner to be calcinated (we
adopt coal-fired thermal oil furnace as heat source). After
calcination, it transports the materials to ball mill for grinding
and modifying. Finally, elevator sends it to branch warehouse of
the silo for storing.
â…¢ Craft introduction of calciner
The demand of gypsum powder is
increasing with the development of gypsum industry. The
manufacturing process of gypsum powder has been improving in order
to cater for the market. Calcination, the hardest to grasp, is key
link in the product and process of gypsum powder. We develop new
generation dehydrating equipment calciner that is good at the
production for all kinds of gypsum powder.
Working principle
The main working principle for calcining system
of calciner
The main body of calciner consists of fine
diameter intensive radiator pipes. Thermal oil fed into the coil
pipes. The heat releases into powder by heat exchanger. Roots
blower installed at the bottom of calciner for putting the cooling
air into furnace by grid plate. The cooling air
blowsgypsum powder in furnace
for reaching boiling state. At certain temperature, the calcined
gypsum powder will lighten, and flow automatically to outlet. This
type gypsum powder is stable in quality. It is easier control the
content of free water, initial and final setting
times.
Moreover, our equipments adopt dry electric
precipitator. Dust collection efficiency is over
*5%.
1.
Simple structure, durable equipment
The boiler does not need rotary components
because the materials has come true fluidization. It simplifies the
structure, manufacture and maintenance. In any case, the furnace
will not damage since it uses low-temperature heat source. The life
span is much longer than normal type.
2.Compact,
space saving
Calciner is a kind of vertical equipment. The
dust collector installed on the top of it as whole body. This
design is good at space saving, and avoids moisture condensation on
corona lines of dust collector.
3. Low
energy consumption
Calciner consumes less electric
energy and heat energy.
Heat energy
(transfer to material from heat source): Almost all of the heat
energy efficiently served as dehydration for materials. Only little
is scattered by the calciner body, and used to heat the cooling air
from the bottom of the fluidized oven. The heat efficiency of
fluidized oven itself is above *5%. Of course, calciner uses
secondary energy. That is, the final heat efficiency is not the
heat efficiency of fluidized oven itself. It is the heat efficiency
of fluidized oven itself multiplying the heat efficiency of other
boiler. However, the steam boiler or thermal oil furnace has higher
heat efficiency as widely used thermal equipment. Normally steam
boiler is ****0%. In addition, normally the thermal oil furnace is
up to ****0%. (Our company adopts organic thermal oil furnace).
Therefore, the final heat efficiency is ****7% if you adopt steam
boiler; it is will up to ****6% when you choose thermal oil
furnace. The traditional calcining equipment uses primary source,
but heat efficiency is no more than *0%. The index of heat
consumption for fluidized oven is 7.7 X **5 KJ/t in
China.
Power energy: Rotary equipment and mixer are not
necessary for calciner. The material completes fluidization by
steam from gypsum dehydration. The power of air blower is smaller
since it only needs a little air for fluidization. For this reason,
calciner consumes less electric energy than traditional
equipment.
4. Good product
quality/ideal compositions/stable property
The phase transition of gypsum
is stable because we adopt low-temperature heat source. Finish
product is nearly no raw gypsum, anhydrous gypsum only less than
5%, and the rest is semi-hydrate gypsum if the discharge
temperature is suitable. The composition is ideal and physical
performance is very steady.
Our company developed completely set
of producing and processing kills on fluidized oven for satisfying
the requirements. We adopt qualified steel as main material. For
example, we adopt seamless steel tube (GB******2) as thermal oil
pipes; we adopt special carbon steel plate and low alloy steel
plate (GB*****6) for oven; we adopt GB products on frame
steel.
Moreover, the welding operators
qualify for working. Avoiding the leakage of thermal oil after
completing weld, we test the water pressure of coil pipes. The
equipment is qualified once no leakage for a period of no less than
*4 hours when the water pressure is up to 0.8—1.0MPa.
â…£ Equipments and technical
parameters
|
No.
|
Name
|
Specification
|
Quantity (set)
|
Function
|
Note
|
|
1
|
Feeding hoper
|
5m³
|
1
|
Batching
system
|
|
|
2
|
Additive agent
hoper
|
1m³
|
1
|
|
|
