Coal Liquefaction

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 a synthetic oil in order to supplement natural

sources of petroleum.  It is an attractive technology because 1) It is well developed and thus could be implemented fairly rapidly and 2) There are relatively large quantities of coal

reserves.

Coal Liquefaction 3. Stable supplies of coal, however, are readily

available worldwide, and the known resources of minable coal are four times that of oil.

Hence, technology is required to make fossil energy consumption efficient and environmentally friendly.

Why CTL……………?

A bit of something………  Coal liquefaction offers promise for nations that are

rich in coal, yet scarce in oil.

 There are four plants in the United States and South

Africa currently using coal as feedstock to create liquid fuels.

 A plant using more than 6 million tons of coal

annually could produce more than 3.6 million barrels of Diesel and Naptha annually, making diesel liquefaction competitive at $35 to $40 per barrel oil prices.

Conti…..  China has earmarked $15 billion for coal-to-

diesel-fuel conversion plants and has targeted replacing 10 percent of its oil imports with coal-liquified oil by 2013.

Main Funda….  Coal liquefaction can be accomplished either directly

or indirectly.

 The difference between these two different types of

coal liquefaction lies in that

1. Indirect coal liquefaction needs to go through

gasification first, 2. while direct coal liquefaction involves making a partially refined synthetic crude oil from coal.  It is widely believed that indirect liquefaction is more

efficient than direct coal liquefaction techniques currently available.

Direct Liquefaction  Single Stage  Two Stage 1. A single-stage direct liquefaction process

produces distillates via one primary reactor or a train of reactors in series. 2. A two-stage direct liquefaction process is

designed to produce distillates via two reactors or reactor trains in series.

Direct Liquefaction  The primary function of the first stage is coal

dissolution and is operated either without a catalyst or with only a low-activity disposable catalyst.  The heavy coal liquids produced in this way are hydro treated in the second stage with a high-activity catalyst to produce additional

distillate.

Indirect liquefaction  Indirect liquefaction involves two steps.

 The first step is the complete breakdown of the coal structure by gasification.  The composition of the gasification products is a mixture of H 2 and CO referred to as syngas.  Sulfur-containing compounds are also removed in this step.

Indirect liquefaction  The

resulting gasification products are reacted in the presence of a catalyst at relatively low pressure and temperature.

 The synthetic liquid products include paraffin's, olefin hydrocarbons or alcohols (particularly methanol), depending on the catalyst selected and the reaction conditions used.

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 of

production of liquid hydrocarbons for use as synthetic fuel by hydrogenation of highvolatile bituminous coal at high temperature and pressure.  It was first developed by Friedrich Bergius in

1913.

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 of hot gas.  The dry product is mixed with heavy oil recycled

from the process along with the catalyst like tungsten or molybdenum sulfides, tin or nickel oleate.  The mixture is pumped into a reactor. The reaction occurs at between 400 to 500 °C and 20 to 70 MPa hydrogen pressure. The reaction produces heavy

oils, 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 convert

the syngas into light hydrocarbons (like ethane) which are further processed into gasoline and diesel.

 This method was used on a large technical scale in

Germany between 1934 and 1945 and is currently being used by Sasol in South Africa.

 In addition to creating gasoline, syngas can also be

converted 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°C

compared to 800 to 1000°C for metallurgical coke.  These temperatures optimize the production of coal

tars richer in lighter hydrocarbons than normal coal tar. The coal tar is then further processed into fuels.  This process was developed by Lewis C. Karrick, an oil

shale technologist at the U.S. Bureau of Mines in the 1920s.

Significance of Coal Liquefaction  Coal liquefaction can significantly improve

national and economic security by lessening dependence on foreign oil and substituting plentiful, more affordable coal.  can be used in current engines, leading to

reduction in all regulated emissions  provides a fuel platform for development of

new generation compression ignition engines Ideal hydrocarbon fuel for fuel cells

World Status

1. Coal liquefaction is a more secure way to

produce liquid fuels that can help the U.S. decrease reliance on oil imports.

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

 China began developing technologies in the 1980s.

coal-to-liquid

fuel

 The coal liquefaction project was given strategic

significance in the mid-1990s, after China became a net oil importer in 1993.  In 1999, China launched its first coal-to-liquid project in Pingdingshan, Central China's Henan Province.



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

 Shenhua Group took the lead in the process in August 2004.

The project is designed to have an annual capacity of 5million tons

 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 a

designed annual production capacity of 2.8 million tons.



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



Two months later, Yankuang Group initiated a huge twophase coal liquefaction project in Yulin. The project is expected to reach an annual output of 10 million tons of oil products by 2020.

 Syntroleum Corporation and Linc Energy are planning to develop a coal-to-liquids (CTL) project in Australia that integrates Fischer-Tropsch technology

with Linc Energy’s underground coal gasification (UCG) technology.  This will be the first such project to combine the two technologies for the production of synthetic diesel from coal.

 The CTL work will be part of Linc Energy’s ongoing Chinchilla Project (350 km west of Brisbane) which also includes early development of an integrated power plant.

 Sasol currently supplies about 28% of South Africa’s fuel needs

from coal, saving the country more than R29 billion (US5,1 billion) a year in foreign exchange.  The South Africa’s petrochemicals giant is promoting its

ambitious Coal to Liquid transportation fuel technology in India that boasts of 248 billion tonnes of coal reserves .  Observing that a CTL plant could produce 500-1000 MW of

export electricity depending on the configuration, he said five such plants could replace 20% of India’s fuel imports by 2020.  A CTL plant having a capacity of three million tonne per

annum could offer a clean diesel production of 68%, Naphtha production 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 regarding

conversion of various shales and coals from NE India into liquid fuel and found that the high sulfur, low ash bituminous coal of NE India is quite amenable for liquefaction  OIL had embarked on coal liquefaction project

based on HRI’s Coal oil co-processing technology and set up a 25 Kg/day pilot plant in 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 the

next several decades

 Coal can play key role in ways that go beyond power

Generation

 Technologies exist to use coal as feedstock for production of

liquid fuels, chemicals, and hydrogen

 Successful demonstrations of advanced technologies could

lead to a new generation of coal plants that coproduce power, liquid fuels, chemicals, and/or hydrogen while capturing and sequestering carbon dioxide