Percoke/Coal 

COAL PREPARATION FOR GASIFICATION AND CWSF

For last 20 years, coal water slurry gasification technology was improved with creation of such fuel as – Coal Water Slurry Fuel - CWSF, which is very close in quality to heating oil with higher calorific value. At the same time price of CWSF is about 3 times cheaper.

APPLICATION OF COAL WATER SLURRY FUEL IN POWER GENERATION as heating oil and coal substitute

Disadvantages of Coal

Despite low price usage of coal has a lot of disadvantages. About 80% of India coal reserves fall under low/medium rank coal, such as lignite and sub-bituminous coal.

It has two major disadvantages; its mineral content and the problems in handling and storing of coal, such as dust and the need for expensive mechanical handling and reclamation systems. By contrast, liquid fuels are naturally low in mineral content, can be freed of their sulfur compounds, and are easily handled and stored. Table 1 above shows it. On the other hand, coal is abundant and fairly cheap to produce

Advantages of CWSF

1. Good Combustion Efficiency

The combustion efficiency of CWSF is 96% - 99%, boiler efficiency is about 90%, which reaches the level of oil

2. Good Effect on Environmental Protection

The Combustion temperature of CWSF is approximately 1200 – 1300ºC and emissions of SO2 and NOx are low

3. Advantages on Technology

CWSF can be transported and burned like oil, non-flammable liquid and its manufacturing temperature is low, so it is safe.

4. Less Investment

The investment in transportation is about 1/3 of railway and 2/5 of electrical wire, and

to be compared with retrofitted to coal, the cost of oil fire boiler retrofitted to CWSF fuel is 1/3 ~1/2 of coal fire boiler, the retrofit time is just 1/3 that of coal fire boiler.

II.3. Coal Water Slurry as New Energy Source

For CWSF Combustion Process, the atomized CWSF burns in the furnace in four stages of combustion:

 

- Moisture evaporation

- Releasing volatile materials and ignition

- Fix carbon combustion

- Coke burn-out

- Ignition temperature: 420ºC – 500ºC (100ºC lower than pulverized coal)

- Combustion temperature: about 1350 to 1380ºC (100ºC – 120 deg C lower than fuel

Oil)

- Fuel oil standard Burner and Nozzle can be used if it is designed with atomized air. If the original system was with atomized air a special burner and nozzle must be used. LeMar’s proprietary technology makes CWSF hydrogenated and does not damage the nozzle.

To calculate cost of CWSF from this coal, we need to go through technology:

1.  Lignite coal is like sponge holding water

The first process is wet pulverization – ball milling to break it into size less than 70 mcm.

2.  Froth Flotation is to remove slog and contaminants. It is based on shown below process. With addition of bio oil (which we can obtain from algae process of CO2

 

utilization) for better separation and quality of fuel and coagulant (gummy substance

or algae).

BIO OIL AND STABILIZING ADDITIVE.

These elements are used for removal of ash/lime from coal when CWSF is prepared. It is done on principal that carbon particles are attracted to fat floating on top of flotation unit and ash/lime is not going down of the unit for collection. In pulverized coal bonds between lime/ash and carbon particles are broken, and carbon particles are stock to oil on top of the flotation unit creating CWSF. The best additive with oil is algae waterweed made of fatty acids. This is 10 times cheaper than use of fuel oil. Also, fatty acids create good fuel additive increasing calorific value of the CWSF. Each power station produces a lot of CO2, which algae feed to grow. Algae grow in bio reactors. Photosynthesis is a biochemical process, during which certain organisms utilize solar energy to “fix” carbon

dioxide (CO2) from the atmosphere into carbohydrates and release oxygen (O2). CO2 + H20 → C6H12O6 + O2. These carbohydrates can then be utilized for energy.

In order to prepare algae for use in CWSF, it is processed through a wet pulverizer

/pump.

The required territory algae grow is not large, as it can be built in levels high. It will take not more than 1 acre of land to grow up 2000 ton per year.

3.  Patented high frequency process provides fuel (CWSF) hydrogenation and stabilization with high frequency unit build around the CWSF pipe of delivery to storage line.

II.         CWSF QUALITY

Coal Water Slurry Fuel (CWSF) Quality

Coal water fuel, or CWSF, is a viscous, heavy liquid fuel that is produced by mixing grounded coal, water, bio oil and chemical additives. CWMF can be stored, pumped

and burned as a substitute for oil or gas in properly modified furnaces or boilers. CWMF burns cleaner than coal, and is free of coal dust or the danger of spontaneous combustion and has a combustion thermal efficiency similar to oil or gas. Please find attached University of Texas report.

CWSF - Advantage

·       Coal water mixture fuel (CWMF) is made approximately 70% of purified coal,

19% of water, 8% of fuel oil or bitumen and 2% viscosity and combustion improvement additives

·       CWMF compared to coal (averages)

o  increases the burning efficiency by 22.5%

o  reduces air pollution by 85%

o  reduces coal consumption by 36.8%

o  reduces cost by about 15% in coal material for end users

·       CWMF can be used in all kinds of industrial boilers, industrial stoves, station boilers, and civil boilers after conversion as a cleaner and cheaper fuel source

Table 1. Comparison of Coal, Heating Oil and CWSM

Description

Heating Oil

CWSM

Coal (brown

better quality)

Furnace Volume Relative

1

1.2

1.6

Heat Release/Average Volume KCal/kg

9 200

6 860*

4 400

Tube bank velocities m/sec

2.8

3.6

10.2

Superheater spacing, cm

10-14

12-16

20-28

Ash content average, %

1

3

32

Boiler efficiency (%) = heat exported by

86

84

76

the fluid (water, steam ..) / heat provided

by the fuel x 100

* Calorific volume of CWSM is combined number of its components and combustion

improvement additive: 62% coal with ash removed provides =5 320 KCal, 8% of fuel oil with 9400 KCal/kg=752 KCal, fuel additive 1% increases calorific value 1.18 times. TOTAL (5 320+752)*1.18=6 860 KCal/kg

Standard Specifications Density :65~70%; Viscosity :~1000CP; Size :d<50μm

Ash :A<4%;

S :S<0.2%。

PROCESS to make CWSF from lignite is:

1)  Wet type pulverization (ball milling) (and Washing if there is a high content of sour water in lignite).

2)  Ash/lime separation in Froth Flotation separation technology, which removes about 60% of ash.

        3)  CWSF – high frequency processing for stability and hydrogenation.