Development status of gasification technologies at home and abroad, industry development status, and market analysis

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The history of coal gasification spans over 100 years, with more than 100 different types of gasifiers existing. These vary in terms of the gas-solid contact mechanism, heat transfer method, feed method, and slag discharge method; as a result, the requirements for the coal used as raw material also differ. Based on the way in which the coal moves within the gasifier, they can be classified into three main categories: fixed-bed, moving-bed, and fluidized-bed gasifiers. Table 1.1 outlines the key characteristics of each type of gasifier. Table 1.1 Main Characteristics of Three Types of Gasifiers
Gasifier Type: Fixed-bed, Fluidized-bed, Gas-flow bed
Ash Discharge Method: Dry ash, Slag, Dry ash, Ash agglomerates, Slag
Characteristics of Raw Coal: Lump coal, Lump coal, Powder coal, Powder coal, Powder coal/water coal slurry
Particle Size: 5–50 mm, 5–50 mm, 0–8 mm, 0–8 mm, 0.1 mm
Coal Rank: Low, High, Low, Unrestricted, Restricted
Operating Pressure (MPa): 2.24, 2.24, 1.0, 0.03–2.5, 2.5–6.5
Operating Temperature (°C): 400–1200, 400–1200, 900–1000, 950–1100, 1200–1400
Coal Gas Temperature (°C): Low, Low, Medium, Medium, High
Oxygen Consumption: Low, Low, Medium, Medium, High
Steam Consumption: High, Low, Medium, Medium, Low
Representative Technologies: Lurgi, LurgiBGL, HTW, KRW/ICC, Shell/Texaco
Fixed-bed pressurized gasification (Lurgi) offers the best thermal efficiency (or cold gas efficiency) and the lowest oxygen consumption. However, it requires the use of low-viscosity or non-sticky lump coal, and the coal gas contains substances such as tar and phenols, resulting in long purification processes and high investment costs. As a result, this technology is rarely used in new gasification projects. Gas flow bed gasification uses fine coal powder with a particle size of <0.1 mm as raw material; the coal powder can be fed in a dry state (Shell) or in a slurry form (water-coal slurry, Texaco). It operates at high temperatures, the gas produced contains no tar, phenols, or hydrocarbons, and it offers the highest gasification efficiency. However, the investment is high and the oxygen consumption is high; it is necessary to use coal with a low ash melting point and low ash content as raw material. Otherwise, fluxes have to be added, which further increases oxygen consumption – this is very unfavorable for nearly 50% of the coal in China that has a high ash melting point and high ash content. Fluidized-bed gasification uses crushed coal as raw material (under 6 mm in size), and the gas produced contains almost no tar, phenols, or hydrocarbons. To prevent the material in the bed from sintering due to high ash content, conventional fluidized beds must operate at relatively low temperatures (below 950°C); therefore, they are only suitable for highly active lignite or subbituminous coal. To overcome this drawback, the ash-melting fluidized bed was developed; by selectively discharging ash, it increases the carbon concentration in the bed and reduces the risk of slag formation, thereby allowing the operating temperature to be raised to 1100°C and expanding its applicability to coals as varied as bituminous coal and even anthracite. Fluidized bed technology features moderate operating temperatures, low investment costs, and wide raw material compatibility, which has led to increasing attention for it; both gasification projects included in the U.S. Vision21 program utilize fluidized bed technology. Our country is the largest market for coal gasification technology in the world, boasting the most comprehensive range of coal gasification processes as well as the highest number of gasifiers. The total number of such gasifiers in various industries exceeds 8,000 units. More than a dozen large-scale Texaco gasification units and Lurgi gasifiers have been introduced to produce chemical synthesis gas and city gas, and several Shell gasification units are currently being introduced (11 units have already been contracted). These efforts have contributed to the modernization of the coal gasification industry. However, most factories (accounting for over 70% of the total capacity) still use outdated atmospheric-pressure fixed-bed gasifiers, resulting in a relatively low overall level of coal gasification technology. At present, large-scale gasification technologies rely entirely on imports, with Texaco’s water-coal slurry technology from the United States and Shell’s dry powder gasification technology from the Netherlands being the most common. Both belong to the category of pressurized fluidized-bed gasification technologies, and they are highly favored due to their advantages such as an effective gas content of 80%–90%, a cold gas efficiency of 75%–83%, a carbon conversion rate of 95%–99%, and a production capacity per furnace of 500–2000 tons per day. However, faced with issues such as huge investment requirements, poor suitability of coal types, and high operating costs in the process of introduction, the vast majority of enterprises can only sigh in frustration. China’s advanced coal gasification technologies are still in the development stage; only the ash-polymerized fluidized bed coal gasification technology has achieved successful industrial demonstration through over two decades of independent research and development. Although it still lags behind Texaco and Shell in terms of certain technical indicators and the production capacity per unit, it boasts significant advantages such as low investment costs, wide adaptability to different coal types, mild operating conditions, and low operational and maintenance expenses. It exhibits great viability and has attracted widespread attention from ** and various enterprises; it holds considerable potential for promoting the gasification transformation of small and medium-sized enterprises. Gasification technology is widely used in China’s chemical, metallurgical, machinery, building materials, and domestic gas industries; currently, the country consumes around 70 million tons of coal for gasification each year. Chemical synthesis enterprises that use petroleum, natural gas, anthracite, and coke as raw materials find it difficult to sustain operations due to high raw material costs, and are seeking cost-effective gasification solutions ； Hundreds of thousands of industrial furnaces and boilers that use fuel or coal are troubled by high fuel prices and environmental emission controls; adopting the gasification route is therefore one of the inevitable options ； To reduce SO2 emissions, **strictly restricting the use and mining of high-sulfur coal, and converting high-sulfur coal into gas to produce chemicals with high added value, represents an effective strategy for improving the overall efficiency of resource utilization** ； China has developed a set of strategies to address oil shortages, and coal gasification – as a technology that helps adjust the structure of energy production and consumption and reduces dependence on oil and gas – is included in the primary level of the oil security strategy ； All these factors will lead to an increasingly large market demand for gasification technology. Most of the existing synthetic chemicals plants (over 70% of the total capacity) still use outdated atmospheric batch water-gas gasifiers. Due to the high cost and severe pollution associated with the raw materials (anthracite, lump coke), there is an urgent need to adopt advanced gasification technologies in order to change the raw material sourcing strategy, with a gasification capacity of 40 million tons per year ； There is a shortage of transportation fuel amounting to nearly 100 million tons. During the 10th Five-Year Plan period, substantial progress will be made in the large-scale commercial development of coal-based synthetic oils and alcohol-ether liquid fuels, with the amount of coal used for gasification reaching tens of millions of tons per year ； Industry burns 400 million tons of coal directly per year or more; to address pollution control, a significant portion of this coal needs to be processed through gasification, with tens of millions of tons of coal being gasified each year ； To improve the quality of petroleum products, the refining industry needs to consume 20–30 billion NM3 of hydrogen each year. The current methods of producing hydrogen from naphtha or refinery dry gas are no longer suitable due to oil shortages; coal gasification represents an economical and reliable alternative, requiring 5–15 million tons of coal to be gasified per year ； The demonstration power plant project for Integrated Gasification Combined Cycle (IGCC) systems, which represents an important development direction in clean coal power generation technology, has already been launched; in the future, the amount of coal that needs to be gasified will be in the order of hundreds of millions of tons per year or more ； It is estimated that investments in coal gasification projects will amount to hundreds of billions of yuan in the future; currently, China spends dozens of billions of yuan each year on introducing large-scale coal gasification technologies. Obviously, it is impossible for the development of gasification technology to rely entirely on imports; moreover, the foreign technologies currently introduced are not suitable for converting the nearly 50% of high-ash-melting-point coals available in our country. The ash fusion fluidized bed coal gasification technology, which possesses independent intellectual property rights, is suitable for most types of coal available in China and requires low investment; it offers a significant competitive advantage for small and medium-sized enterprises. At its current level of industrial development, it is already capable of capturing a share of the low-end market. If this project is implemented, the development of high-pressure large-scale systems is expected to be completed in a short period of time, reaching international advanced levels, and at that time it will be able to compete with foreign technologies.