First pilot plant to convert high ash coal to methanol developed

India has developed an indigenous technology to convert high ash Indian coal to methanol and established its first pilot plant in Hyderabad, the Department of Science and Technology said on Friday. The broad process of converting coal into methanol consists of conversion of coal to synthesis (syngas) gas, syngas cleaning and conditioning, syngas to methanol conversion, and methanol purification, it said

The broad process of converting coal into methanol consists of conversion of coal to synthesis (syngas) gas, syngas cleaning and conditioning, syngas to methanol conversion, and methanol purification, it said. Coal to methanol plants in most countries are operated with low ash coals. Handling of high ash and heat required to melt this high amount of ash is a challenge in the case of Indian coal, which generally has high ask content, it mentioned.

In order to overcome this challenge, Bharat Heavy Electricals Limited (BHEL) has developed the fluidised bed gasification technology suitable for high ash Indian coal to produce syngas and then convert syngas to methanol with 99 per cent purity. BHEL has integrated its existing coal to syngas pilot plant at Hyderabad with a suitable downstream process for converting syngas into methanol.

This pilot-scale project with a methanol generation capacity of 0.25 metric tons per day has been initiated by NITI Aayog and funded by the Department of Science and Technology (DST) under Clean Energy Research Initiative, the statement said. Currently, the pilot plant is producing methanol with purity of more than 99 per cent. Scaling it up will help in optimum utilisation of the country’s energy reserves and accelerate its journey towards self-reliance, it added.

India is pushing thermal coal gasification for domestic production of methanol and urea. Coal to methanol is a proven technology and India can easily tap its large coal reserves to produce methanol as a substitute or drop-in fuel for gasoline and diesel. According to India’s think-tank NITI Aayog, high methanol blends offer significant vehicle efficiency improvement potential of 25 per cent. A fertiliser plant at Talchar in the eastern state of Odisha has already embarked on a project to produce 1.26 million tonnes per annum (MMPTA) of neem coated urea through the coal gasification process. The plant is designed to use 3.3 MMTPA of coal from Talcher mines. It is expected to be operational by 2023-2024. Coal India Limited is also working on setting up a coal-based methanol plant in Kolkata. It plans to produce 6.76 lakh tonnes of methanol per annum at Dankuni Coal Complex (DCC) of South Eastern Coalfields Ltd (SECL), a subsidiary of the state-run company.

According to energy consultant Atanu Mukherjee; “methanol can be used for producing methanol-based chemicals and olefins for plastics and as a substitute for petrol, diesel and LPG. Close to 15 percent of the petrol used today in vehicles can be substituted by methanol. Additionally, 20 percent of imported diesel and cooking gas can be substituted by domestically produced methanol. Over 15 percent of plastics/olefins feedstock based on imported crude oil heavy distillates can be replaced by coal gasification-based methanol saving over US$5 billion in imported naphtha. ”He says by enriching and exploiting Indian coal endowments through gasification and carbon capture a clean coal-based economy for power, chemicals, fuels, steel, oil, and fertilizers can enable a US$50-billion direct increase in the gross domestic product (GDP) while creating employment for over half-a-million people, reducing imports by over US$30 billion and cutting the current account deficit by 50 percent.

Coal gasification

Coal gasification – Coal-to-Gas – is one of the several options being tried to make coal environmentally less toxic to the air. It is a process of converting coal into synthetic gas (syngas), which is a mixture of carbon monoxide (CO), hydrogen (H2), Carbon dioxide (CO2), natural gas (CH4) and water vapour (H2O), from coal and water, air and/or oxygen. During gasification, coal is blown with oxygen and steam while also being heated under high pressure. During the reaction, oxygen and water molecules oxidize the coal and produce syngas. Historically, the process had been used in the early 1800’s to produce coal gas, or “town gas”, in the US town of Baltimore for municipal lighting and heating.

Today, it is primarily used for electricity generation or for production of chemical feedstocks. The hydrogen obtained from coal gasification can be used for various purposes such as powering hydrogen economy or upgrading fossil fuels or converting the syngas into transport fuels like gasoline, methanol, naphtha and diesel and chemical fertilizers through additional treatment. Over the past 20 years, pushed by regulation and facilitated by the use of markets, the power industry and the equipment manufacturers that serve it have already done a remarkable job in eliminating pollution from coal. Some 99.9 percent of particulates, 99 percent of sulphur dioxide (SO2) and 95 percent of nitrogen oxides (NOx) emissions have been banished by new coal plants which use ultra-supercritical technology. But the amount of carbon, embedded in the carbon dioxide emitted by burning coal, is an altogether different and a much more intractable problem.

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