Coal Liquefaction

Coal can be converted to liquid fuels either by removal of carbon or addition of hydrogen.

The first approach is known as carbonization, and the second is known as liquefaction.

The major objective of coal liquefaction is to produce synthetic oil to supplement the natural sources of petroleum.

Coal Liquefaction

Coal liquefaction is the conversion of coal into asynthetic oil in order to supplement naturalsources of petroleum.

It is an attractive technology because

1) It is well developed and thus could beimplemented fairly rapidly and

2) There are relatively large quantities of coalreserves.

Coal Liquefaction

3. Stable supplies of coal, however, are readilyavailable worldwide, and the knownresources of minable coal are four times thatof oil.

Hence, technology is required to make fossilenergy consumption efficient andenvironmentally friendly.

Why CTL……………?

A bit of something………

Coal liquefaction offers promise for nations that arerich in coal, yet scarce in oil.

There are four plants in the United States and SouthAfrica currently using coal as feedstock to createliquid fuels.

A plant using more than 6 million tons of coalannually could produce more than 3.6 million barrelsof Diesel and Naptha annually, making dieselliquefaction competitive at $35 to $40 per barrel oilprices.

Conti…..

China has earmarked $15 billion for coal-to-diesel-fuel conversion plants and hastargeted replacing 10 percent of its oilimports with coal-liquified oil by 2013.

Main Funda….

Coal liquefaction can be accomplished either directlyor indirectly.

The difference between these two different types ofcoal liquefaction lies in that

1. Indirect coal liquefaction needs to go throughgasification first,

2. while direct coal liquefaction involves making apartially refined synthetic crude oil from coal.

It is widely believed that indirect liquefaction is moreefficient than direct coal liquefaction techniquescurrently available.

Direct Liquefaction

Single Stage

Two Stage

1. A single-stage direct liquefaction processproduces distillates via one primary reactor ora train of reactors in series.

2. A two-stage direct liquefaction process isdesigned to produce distillates via tworeactors or reactor trains in series.

Direct Liquefaction

The primary function of the first stage is coaldissolution and is operated either without acatalyst or with only a low-activity disposablecatalyst.

The heavy coal liquids produced in this wayare hydro treated in the second stage with ahigh-activity catalyst to produce additionaldistillate.

Indirect liquefaction

Indirect liquefaction involves two steps.

The first step is the complete breakdown of thecoal structure by gasification.

The composition of the gasification products is amixture of H 2 and CO referred to as syngas.

Sulfur-containing compounds are also removedin this step.

Indirect liquefaction

The resulting gasification products arereacted in the presence of a catalyst atrelatively low pressure and temperature.

The synthetic liquid products includeparaffin's, olefin hydrocarbons or alcohols(particularly methanol), depending on thecatalyst selected and the reaction conditionsused.

Types of Processes

Alternatively, coal can be converted into a gas first, and then into a liquid, by using the

1. Fischer-Tropsch process

2. Bergius process

3. Low Temperature Carbonization (LTC)

Bergius Process

The Bergius Process is a method ofproduction of liquid hydrocarbons for use assynthetic fuel by hydrogenation of high-volatile bituminous coal at high temperatureand pressure.

It was first developed by Friedrich Bergius in1913.

Bergius Process

This process was used by Germany during World War I and World War II and has been explored by SASOL in South Africa.

Several other by GULF oil:-

1. SRC-I

2. and SRC-II (Solvent Refined Coal)

Bergius Process

The coal is finely ground and dried in a stream ofhot gas.

The dry product is mixed with heavy oil recycledfrom the process along with the catalyst liketungsten or molybdenum sulfides, tin or nickeloleate.

The mixture is pumped into a reactor. The reactionoccurs at between 400 to 500 °C and 20 to 70 MPahydrogen pressure. The reaction produces heavyoils, middle oils, gasoline, and gases.

Fischer-Tropsch Process (FTP) It is an indirect route, coal is first gasified to make

syngas .

Next, Fischer-Tropsch catalysts are used to convertthe syngas into light hydrocarbons (like ethane) whichare further processed into gasoline and diesel.

This method was used on a large technical scale inGermany between 1934 and 1945 and is currentlybeing used by Sasol in South Africa.

In addition to creating gasoline, syngas can also beconverted into methanol, which can be used as a fuel,or into a fuel additive.

Low Temperature Carbonization (LTC)

This also convert coal into a liquid fuel.

Coal is coked at temperatures between 450 and 700°Ccompared to 800 to 1000°C for metallurgical coke.

These temperatures optimize the production of coaltars richer in lighter hydrocarbons than normal coaltar. The coal tar is then further processed into fuels.

This process was developed by Lewis C. Karrick, an oilshale technologist at the U.S. Bureau of Mines in the1920s.

Significance of Coal Liquefaction Coal liquefaction can significantly improve

national and economic security by lesseningdependence on foreign oil and substitutingplentiful, more affordable coal.

can be used in current engines, leading toreduction in all regulated emissions

provides a fuel platform for development ofnew generation compression ignition enginesIdeal hydrocarbon fuel for fuel cells

World Status

1. Coal liquefaction is a more secure way toproduce liquid fuels that can help the U.S.decrease reliance on oil imports.

•According to a recent forecast by the EIA, liquidfuels from coal will account for about 3% of thetotal U.S. supply of petroleum products by 2030

China began developing coal-to-liquid fueltechnologies in the 1980s.

The coal liquefaction project was given strategicsignificance in the mid-1990s, after China becamea net oil importer in 1993.

In 1999, China launched its first coal-to-liquidproject in Pingdingshan, Central China's HenanProvince.

In 2001, a high-tech research project, the 863Programme, picked up the pace on coal-to-liquidfuel projects.

Shenhua Group took the lead in the process in August 2004.The project is designed to have an annual capacity of 5milliontons

The first, designed to produce 3.2 million tons of oil products,is scheduled for production by 2007.

The second phase is scheduled for production by 2010, with adesigned annual production capacity of 2.8 million tons.

In February 2006, a coal liquefaction project with a designedinitial annual capacity of 160,000 tons was launched by Lu'anGroup in Tunliu, Shanxi Province.

Two months later, Yankuang Group initiated a huge two-phase coal liquefaction project in Yulin. The project is expectedto reach an annual output of 10 million tons of oil products by2020.

Syntroleum Corporation and Linc Energy areplanning to develop a coal-to-liquids (CTL) project inAustralia that integrates Fischer-Tropsch technologywith Linc Energy’s underground coal gasification(UCG) technology.

This will be the first such project to combine the twotechnologies for the production of synthetic dieselfrom coal.

The CTL work will be part of Linc Energy’s ongoingChinchilla Project (350 km west of Brisbane) whichalso includes early development of an integratedpower plant.

Sasol currently supplies about 28% of South Africa’s fuel needsfrom coal, saving the country more than R29 billion (US5,1billion) a year in foreign exchange.

The South Africa’s petrochemicals giant is promoting itsambitious Coal to Liquid transportation fuel technology inIndia that boasts of 248 billion tonnes of coal reserves .

Observing that a CTL plant could produce 500-1000 MW ofexport electricity depending on the configuration, he said fivesuch plants could replace 20% of India’s fuel imports by 2020.

A CTL plant having a capacity of three million tonne perannum could offer a clean diesel production of 68%, Naphthaproduction of 30% and LPG 2%

Current and Potential Future CTL Worldwide

GTL Qatar: 800,000 BPD (Shell, Sasol, ConocoPhillips, ExxonMobil, Marathon)

Other GTL Worldwide: 480,000 BPD (includes existing

plants and proposed plants in Iran, Russia, Australia,

and Nigeria)

CTL Sasol South Africa 150,000 BPD

CTL Sasol Potential Plants in China 160,000 BPD

Bench & pilot facilities at Rentech, Syntroleum, and

ConocoPhillips

Indian Scenario

OIL carried out in-depth studies regardingconversion of various shales and coals from NEIndia into liquid fuel and found that the highsulfur, low ash bituminous coal of NE India isquite amenable for liquefaction

OIL had embarked on coal liquefaction projectbased on HRI’s Coal oil co-processingtechnology and set up a 25 Kg/day pilot plantin Duliajan, Assam.

OIL Project Milestone

OIL’s Coal liquefaction Pilot Plant

Pilot plant in collaboration with HRI, USA Coal processing capacity of the plant - 25 kg/day Plant is equipped with ebullated bed reactor,

high pressure pumps and vessels Highly sophisticated - process monitoring,

control and data acquisition with the help of PLC based control

system Plant commissioned in March 1999 Total cost of the project - Rs. 15 crores

Why Coal to Liquid Energy Security:

– Size of coal resources– Distribution of resources

Environment– Utilization of clean coal technology– Sequestration technology expected

Flexibility– Advanced technology– Co-production capability

Economics– Competitive with alternatives– World oil price volatility

Barriers to Coal-To-Liquids Technical

– Integrated operations of advanced CTL technologies have never been demonstrated

Economic

– Uncertainties about future world oil production

– High capital and operations costs

– Investment risks

– Energy price volatility

Environmental

– CO2 and criteria pollutant emissions

– Expansion of coal production and requisite infrastructure (railroads, railcars, etc.)

– Water use

Barriers to Coal-To-Liquids

Commercial Deployment

– Competition for critical process equipment, engineering, and skilled labour

– Who would take the lead in commercial deployment? Part power part liquid fuels

Social

–public resistance to coal use

Conclusions

Many complex energy challenges face America over thenext several decades

Coal can play key role in ways that go beyond powerGeneration

Technologies exist to use coal as feedstock for production ofliquid fuels, chemicals, and hydrogen

Successful demonstrations of advanced technologies couldlead to a new generation of coal plants that coproducepower, liquid fuels, chemicals, and/or hydrogen whilecapturing and sequestering carbon dioxide