Dalian to build China’s first clean coal chemical industry base

In 1978, the high-temperature Winkler HTWTM gasification pilot plant was put into operation in Wagsthal, Germany, with a gasification pressure of 1.0 MPa. The extensive operational experience accumulated by this facility provided a solid practical foundation for the industrial methanol plant using Rhine lignite, which was built and put into operation in Bingen, Germany, in 1986. The German HTWTM gasification unit for large-scale industrial lignite in fluidized bed operation can achieve an annual operating time of over 8,000 hours. In 1988, another industrial lignite fluidized-bed HTWTM gasification plant was built and put into operation in Oulu, Finland; this plant was used to produce synthetic ammonia from peat. To develop the application of the high-temperature Winkler HTWTM gasification process in integrated gasification combined cycle power generation (IGCC), a high-temperature Winkler HTWTM gasification unit with a gasification pressure of 2.5 MPa was successfully commissioned in Wesel, Germany, in 1989. By the mid-1990s, the high-temperature Winkler HTWTM gasification unit in Wesseling, Germany, used air instead of oxygen as the gasifying agent, enabling a carbon conversion rate of 95%. Meanwhile, in Germany’s large lignite fluidized-bed HTWTM gasification plant in Wittenberg, a project using a mixture of plastic waste and lignite as the gasification feedstock is also underway. Due to the excellent process reliability of the high-temperature Winkler HTWTM gasification technology, Sumitomo Heavy Industries in Japan adopted this technology for gasifying municipal waste; this plant was successfully put into operation in Japan in 2000. In December 2010, ThyssenKrupp Industrial Engineering acquired from the Rhine Lignite Group all the intellectual property and expertise related to the high-temperature Winkler HTWTM gasification technology, and built a pilot plant in Darmstadt, Germany, for testing coal samples as well as for further research and development of this gasification technology. This pilot plant is scheduled to be commissioned in June 2015. The company behind the high-temperature Wickler HTWTM gasification technology is ThyssenKrupp Industrial Solutions, an engineering contractor headquartered in Dortmund, Germany. With its highly skilled workforce – comprising over 5,600 employees worldwide – and its international network of subsidiaries and branches across the globe, it has so far completed more than 2,000 projects around the world. Through years of practical experience in engineering, ThyssenKrupp Industrial Engineering possesses extensive international expertise in gasification units, having designed, constructed, and successfully put into operation over 100 such units worldwide. 1. Characteristics of gasification technology and process flow: The high-temperature Winkler HTWTM gasification technology is a pressurized bubble-type fluidized-bed gasification method that is widely applicable to low-quality coals such as lignite. Its gasification process includes a feed unit, a gasification unit, a syngas cooling unit, a dry dust removal unit, and a syngas washing unit. The raw coal passes through drying and pre-treatment units, where it is crushed and dried into coal powder that meets the requirements of the high-temperature Winkler HTWTM gasification process. It then moves through a coal lockhopper system, an anchor feeder, and a screw feed system, being pressurized from atmospheric pressure to the gasification pressure before being fed into the gasifier. In the gasifier, the gasification temperature must be kept below the ash melting point of the coal feed. Inside the furnace, it can be divided by temperature into a lower fluidized bed zone and an upper secondary gasification zone. In the fluidized bed area, there is a relatively uniform temperature distribution as well as quite dense solid particles. To maintain the fluidized state of the coal feed, most of the steam is injected into the gasifier through nozzles at the bottom of the gasifier to serve as a fluidizing gas, while the remaining steam, along with oxygen, is injected into the gasifier through nozzles at various levels within the gasifier to act as a gasifying agent. Distributed oxygen supply can effectively prevent the formation of large slag masses. During the gasification process, the syngas leaves the fluidized bed area carrying a small amount of fly ash and enters the secondary gasification zone. The solid density in this region is low; therefore, to achieve a higher carbon conversion rate and prevent the formation of by-products, a gasifying agent still needs to be injected in the secondary gasification zone. Due to the increase in vaporization pressure (up to 3.0 MPa), the diameter of the vaporization furnace decreases, resulting in a more significant effect of secondary vaporization. The vast majority of the fly ash entrained in the syngas is separated by a high-efficiency cyclone separator and recovered back into the fluidized bed via a circulation leg for re-gasification. The ash discharged from the bottom of the gasifier is sent to the lockhopper system via a spiral cooling conveyor system. After leaving the cyclone separator, the gasified syngas enters a waste heat boiler to recover waste heat, thereby producing medium-pressure and high-pressure saturated steam as a by-product. After being cooled in a waste heat boiler, the syngas enters a ceramic filter for thorough dust removal. The filtered fly ash adheres to the outer surface of the ceramic filter element; possessing the adsorption properties of activated carbon (unfused fly ash), it is capable of effectively removing most of the salts, heavy metals, and other harmful substances present in the syngas, thereby significantly reducing the amount of wastewater generated in the subsequent washing units. In the washing unit, the residual salts, fine ash, and other impurities in the syngas are further removed. Technical advantages: (1) Wide range of feedstock compatibility: The high-temperature Wenker HTWTM gasification technology exhibits great adaptability to various feedstocks. Through nearly 50 years of technological development and the accumulation of practical experience, it has successfully processed a wide array of feedstocks worldwide, including highly active lignite and long-flame coal, coal with high melting points, high ash content, and high sulfur levels, biomass, and municipal waste. It is the optimal gasification technology for low-quality coals. (2) Pressurized fluidized bed gasification technology: The maximum gasification pressure reaches 3.0 MPa. As the gasification pressure increases, the reaction rate of the gasification process speeds up, and the processing capacity per unit area of the gasifier increases. This facilitates an improvement in the plant’s production capacity, as well as easier purification of the syngas and better pressure alignment with downstream process systems. (3) Environmental protection and water conservation: Since the gasification temperature is lower than the ash melting point of coal, dry slag and ash removal methods along with the reuse of such slag are employed, which prevents the generation of black water rich in tar and phenols. The amount of waste water produced is extremely low, its treatment is simple, and industrial emissions are virtually zero. (4) Low cost, high efficiency: The High-Temperature Wenker HTWTM gasifier is a pressure vessel with a refractory lining; it contains no internal components, and features a simple structure, low maintenance costs, and reliable operation. The cold gas efficiency of the high-temperature Wenker HTWTM gasification process is greater than 77%, with a carbon conversion rate of over 95%. (5) Reliable process and industrialization achieved: The reliability of the high-temperature Wenker HTWTM gasification technology has been fully verified in the lignite-to-methanol industrial project in Bitterfeld, Germany. 12 years of reliable operation, with an average equipment uptime of over 85%, and an uptime of 91% in the best year. II. Technical Parameters Table
Gasification Technology Type: Dry-powder pressurized fluidized-bed gasification technology
Name of Gasification Technology: High-temperature Winkler HTWTM gasification technology
Types of Gasifiers: Various types available, capable of handling up to 3,800 tons of coal per day depending on the project requirements
Combination of Gasifiers: Additional gasifiers can be installed as needed based on the project’s characteristics
Feeding Method: Feeding is carried out using a hopper system and a high-pressure spiral feeding system
Feeding Location: The lower fluidized-bed area of the gasifier
Nozzle Type and Features: Specialized equipment is used
Flow Pattern: Pressurized bubbling fluidized bed
Refractory Lining: Specialized lining materials are utilized
Cooling Method for Syngas: Waste heat boiler
Gasification Medium: Steam, oxygen/air
Stage of Technical Implementation: Multiple large-scale industrial applications have been realized
Operating Cycle: Reliable operation for 12 consecutive years; average equipment uptime exceeds 85%, with 91% uptime in the best years
Coal Particle Size Range: 0–10 mm
Suitability of Coal Types: Peat, lignite, long-flame coal, coal with high ash, sulfur, and melting points, biomass, municipal waste, etc.
Industrial Analysis of Coal: The optimal coal types are as follows:
Carbon content (on a dry, ash-free basis): 40–80 wt%
Volatile matter (on a dry, ash-free basis): 38–88 wt%
Ash content (on a dry basis): ≤ 45 wt%
Sulfur content: No specific requirement
Operating Conditions: Gasification temperature: 200–300°C below the ash melting point; Gasification pressure: 1.0 MPa–3.0 MPa
Composition of Raw Syngas: CO – 29.4 vol.%; H2 – 29.5 vol.%; CO2 – 18.8 vol.%; CH4 – 4.0 vol.%; N2+Ar – 0.5 vol.%; H2O – 17.5 vol.%; Others – 0.3 vol%. These values refer to the results of gasifying low-ash lignite using pure oxygen.
Process Parameters: Oxygen consumption: ≤ 300 Nm3/1000 Nm3 (CO+H2); Steam consumption: Varies depending on the specific project; Syngas production rate: The effective syngas output per gasifier (CO+H2) can reach up to 155,000 Nm3/h; Carbon conversion rate: Greater than 95%
Suitable for Industrial Applications: Ammonia production, methanol production, hydrogen production, synthetic natural gas production, synthetic oil production, IGCC, etc.
III. Operational Examples: After more than 50 years of development, the high-temperature Winkler HTWTM gasification process has achieved numerous successful industrial applications around the world. Among them, the high-temperature Winkler HTWTM lignite-to-methanol industrial demonstration plant established in Bielefeld, Germany, in 1986, includes process units such as syngas purification, compression, carbon monoxide conversion, as well as desulfurization and decarbonization, in addition to the HTWTM gasification island. In this industrial demonstration unit, each gasification furnace has a coal feeding rate of 720 tons per day, an operating pressure of 1.0 MPa, and a syngas production capacity of 54,000 standard cubic meters per hour; the syngas is used as the feed gas for methanol production. By the end of 1997, this facility had accumulated 670,000 hours of operation, gasified 1.6 million tons of dry lignite in total, and produced 800,000 tons of methanol. The reliability of the high-temperature Wenker HTWTM gasification technology has been fully verified in this industrial demonstration project. 12 years of reliable operation, with an average equipment uptime of over 85%, and an uptime of 91% in the best year. This industrial demonstration unit is the pressurized fluidized bed gasification unit with the longest operating time and highest reliability in the world to date.

Is this gasification technology used in China?

This technology is a fundamental, original technology; it represents the pioneering basis for various modern coal chemical processing technologies. Conducting research and development on such projects in China requires a great deal of patience

SASOL also has this technology