Page 213 - New Trends In Coal Conversion

176 New Trends in Coal Conversion

Trying to achieve the Agreements of the 2015 United Nations Climate Change
Conference (COP 21) to reduce greenhouse gas emissions, one of the trends during
the last years has been the development of “clean coal technologies (CCTs)”. In this
context, coal gasification is considered as a cleaner approach than other alternatives,
which is one of the reasons why the number of coal gasification projects has increased
over the last years, especially in Asia (Higman, 2014, 2016, 2017).
Coal gasification by which coal is converted into a fuel gas rich in hydrogen and
carbon monoxide has been undertaken industrially for over 200 years. The oil crises
of the 1970s prompted a renewed interest in advanced coal utilization technologies.
One technology, integrated gasification in combined cycle (IGCC), allowed gener-
ating power from coal at high efficiency with low emissions. This sparked research,
development, and commercialization of these plants during the 1980s and 1990s.
More recently, some of the coal gasification plants have addressed the issue of
carbon capture and sequestration or are being linked to polygeneration strategies,
varying the usage of the clean syngas between power production and chemical
synthesis.
This chapter reviews and summarizes the current status of coal gasification world-
wide. Despite the closure of several of the most relevant commercial coal gasification
plants in Europe and the United States, gasification has increased in recent years,
particularly in China. Moreover, technologies have diversified.
In the following sections, the current status of coal gasification is presented and dis-
cussed. Information has been compiled according to continent and country. The most
relevant cases and projects are discussed in more detail.

7.2 Current status of coal gasification

7.2.1 Asia
7.2.1.1 China

Coal is the dominant primary energy in China, accounting for about 64% of the total
primary energy consumption in 2015. Although coal gasification only means 5% of
China’s total coal consumption, China has the biggest number of coal gasification pro-
jects in the world due to the support of the Chinese Government through its 9the12th
Five-Year Plans whose aim is to implement a Clean Coal Technology Program as a
major component of the National Energy Plan (Chang et al., 2016).
As shown in Fig. 7.1, there is a wide range of coal gasification technologies being
supplied in China by overseas vendors, and an increasing use of domestic technologies
is under way. Different technology variants are in operation, entrained flow, fixed bed,
slagging, transport, and fluidized bed. Chinese-developed systems include opposed
multiburner (OMB) gasification and multicomponent slurry gasification. Various
coal types are gasified to produce a range of products that include ammonia, oxo-
chemicals, methanol, SNG, CO, hydrogen, propylene, DME, gasoline, LPG, acetic
acid, butanol, octanol, urea, methane, and ethylene glycol (Mills, 2016).