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CURRENT STATUS OF TECHNOLOGY AND TRENDS

gaps, and scope of improvement is extensive. There are many new developments in the
process and catalysts for different segments of the production chain, but there are not many
proven technologies yet.
As a basis for discussing the proven and emerging technologies, a break-down of the individual
components of the carbon source to methanol/DME production chain is given below in Fig. 9

FIG. 9

Pretreatment Pretreatment Shift Preparation
of Carbon of Syngas Reaction of Methanol/
Source DME

• Natural Gas • Gasifiers for Gas • High Temperature Shift • Vapor Phase
• Coal/Residue • Gasifiers for Solid • Low Temperature Shift • Liquid Phase
• Biomass source • Catalyst design • Dehydration of
• Municipal waste • Oxygen Separaion • Hydrogen Separation Methanol
• Flue Gasses • Methane reforming • Single step DME
• Bio gas • CO +H reforming • Catalyst
2
2
• Purification
• Plasma Gasification

From the source of hydrocarbon, to methanol/DME production, there are many possibilities,
and several of them are not yet fully matured for commercial application. Further, the low cost
of production of methanol/DME from natural gas prevents other possibilities for technology
development. However, with the recent interest in reduction in GHG emission and using
gasoline/diesel compatible liquid fuels from renewable resources, as well as the increased
problems of disposal of waste, the use of non-fossil sources for methanol production is gaining
importance. In the following sections the current status of available technologies is elaborated
for some of these areas, particularly from coal and from renewable sources.

3.7 Pretreatment of Carbon Source

Feed pre-treatment for natural gas is well established and most of the licensors can design
suitable gas cleaning systems depending upon natural gas quality. However, for coal and
biomass, the picture is entirely different due to the diversity of types of these solid hydrocarbon
sources. In case of coal, there is a wide variance in the characteristics of coal and ash content,
and its softening point. This also includes the underground gasification of coal. There are many
coal based methanol plants in China, and their modern high temperature gasifier designs,
which operate above the ash melting point, can handle low melting high ash coals. The current
technology to convert all types of coal to syngas is fairly matured, using high temperature and
pressure gasification in entrained bed gasifiers with oxygen. Although slurry bed gasifiers are
available, the gasification efficiency is relatively low, therefore dry coal is preferred. Large
scale coal gasifiers operate with processing capacity of the order of 2000 TPD producing 1000
TPD of DME [45].
For varieties of biomass such as wood, agricultural waste, municipal waste, paper mill black
liquor, refinery off gases, land fill and anaerobic digester biogas etc. the picture is quite different.
Due to their inherent nature, each of these types of feedstocks has to be treated using a

Methanol and DME Production: Survey and Roadmap | 2017 53