New coal-based urea production should still be encouraged

According to this view, which small-capacity, fixed-bed systems are destined to be phased out?

Using water-coal slurry to produce gas should be the path for the development of coal-based chemical industry in the future.

Second-generation technology will eventually replace first-generation technology. It is an inevitable law of history that those who fall behind will be eliminated.

The market is merciless; elimination is inevitable. Just like black-and-white televisions, no one will see them in a couple of years.

This post was last edited by ch3ohnh3 on 2009-12-8 at 21:12. Not necessarily; please read on: The applicability of coal chemical technology is more important than its sophistication. Given the wide variety of coal gasification technologies that have been developed independently in China as well as those that have been imported, coal chemical companies always strive to find the best available technologies. Recently, interviews were conducted with Yang Chunsheng, vice president of the China Nitrogen Fertilizer Industry Association, Tang Hongqing, former deputy chief engineer of Sinopec Ningbo Engineering Co., Ltd., and Bu Xuepeng, a researcher at the Beijing Coal Chemical Research Institute under the China Coal Research Institute. Experts unanimously agree that a scientific approach is needed to understand and select gasification technologies; there is no such thing as advanced or backward gasification technologies – only those that are suitable for specific applications. 　　Throughout the years, there has been a debate regarding the superiority and inferiority of three types of gasification technologies: fixed-bed, fluidized-bed, and gas-flow bed. Yang Chunseng believes that no coal gasification technology is universal or applicable in all situations; some technologies have broader application conditions while others have narrower ones, just as bicycles, cars, and trains each have their own uses. Yang Chunseng pointed out that due to the differences in coal types, products, and plant construction conditions in our country, diversification of raw materials and gasification technologies is inevitable. The coexistence of various gasification technologies is suitable for the current situation of China’s diverse coal resources. 　　Tang Hongqing explained that coals such as anthracite and those with low calorific value are suitable for use in atmospheric pressure fixed-bed gasification furnaces. Moreover, the slag produced by these furnaces can be sent to waste treatment plants for combustion to generate electricity, while wastewater can be discharged without any emissions, thus meeting environmental standards. 　　Bu Xuepeng said that in large-scale coal chemical parks, different gasification technologies can coexist and be used together. Using two or three of the fixed-bed, fluidized-bed, and pneumatic-bed gasification technologies simultaneously has the advantage of allowing the feed coal to be simply screened first; coal lumps of 10–50 mm can be used directly in fixed-bed pressurized gasification without the need for drying. The 1–10 mm fraction can be used in fluidized beds, or it can be used together with lump coal smaller than 1 mm in gas-flow bed gasification, which can reduce coal preparation costs to a certain extent. Moreover, the combined use of several gasification technologies can complement each other; the large amount of methane produced by fixed-bed gasification can be used for drying coal in fluidized-bed systems or for generating electricity in gas turbines. 　　Tang Hongqing explained that some gasification technologies have high oxygen consumption, but other technical aspects of them are advantageous. Furthermore, the efficiency of coal gasification technology cannot be determined by the level of water vapor content in the syngas; it should be assessed based on the entire process from coal gasification technology to the final product. Tang Hongqing pointed out that it is unscientific to choose a gasification technology by simply comparing certain technical indicators obtained under unequal conditions. Just because a certain technology has shortcomings does not mean it should be completely rejected. 　　Experts suggest that when choosing gasification technology, enterprises should first select the most suitable one based on their own coal resources; secondly, they need to consider the products to be produced. As long as it is economically feasible, gasification technologies available domestically or abroad can all be considered. In fact, if you look at companies involved in new types of gasification, you’ll find that for many of them the cost of coal simply isn’t enough to offset the financial burdens resulting from high investment costs! Moreover, there is no competitive advantage in terms of overall energy consumption; however, the biggest advantage is the expansion of the sources of coal, and the above points reflect this reality. b] 1# huaandhua