In accordance with the Air Pollution Prevention and Control Act, article 28, item 2, the standard for the proportion and composition of fuel blends, and the substances that are prone to air pollution in article 29, are to grasp the operation of fuel blending in public and private places in Taiwan. The main work priorities of this year include: 1. Studying the current status of domestic co-firing and mastering the status of domestic process operations, 2. Collecting foreign co-firing regulations as a reference for assessing domestic process co-firing standards, 3. Assisting in the development of stationary sources for the use of fuel and auxiliary fuels for mixed combustion in Taiwan.
According to the literature reviews, there are no clear regulations on the definition of major fuels and auxiliary fuels and the restrictions on the proportion of controlled co-firing in foreign countries. At present, the control strategies for air pollutant emissions from burning sources in the world are roughly divided into 1. The source controls of the fuel quality and its component specification, 2. Defines the fuel usage area or controls/prohibits the users of specific fuels, 3. Set and meet the air pollution emission standards (volume concentration, mass concentration, performance standards (such as lb/MMBtu or lb/ton clinker) or reduction rate). For the owners or operators of stationary sources, the measures to control the fuel quality include limit to use the hazardous wastes as fuels, set the fuel quality standards, restricting the usage area of specific fuels, and adopt the BAT and apply to more stringent emission standards as the fuel quality exceeds the certain limit. As so far, most of the domestic stationary sources adopt the methods of end-of-pipe control to reduce the emission concentration and amounts of air pollutants. For large-scale emitters, most of them can effectively control and monitor the removal efficiency of their air pollution control facilities. However, for some small and medium-sized stationary sources, the air pollution control devices that may be incorrectly installed or insufficient due to insufficient knowledge or experience. Based on cost considerations, those air pollution control facilities installed at small and medium-size emitters maybe fail to operate properly or use inexpensive or poorly-quality fuels/raw materials.
Based on the 2016 air pollution fee payment database from EPA, we analyze and evaluate the industrial classification, stationary sources type, fuel type and sulfur content of the coals for all the heating facilities used in the stationary sources subject to relevant rules. The results showed that the industries of the co-firing facilities were mainly cement (cement and its products manufacturing), paper (other paper products manufacturing and pulp, paper and cardboard manufacturing), electricity (electricity supply and steam supply), and the textile industry (man-made fiber manufacturing, printing and dyeing finishing, spinning, textile manufacturing and weaving). The main types of pollution sources are rotary kilns, preheaters, fluidizing beds and boilers. The types of co-firing of different types of pollution sources and the types of co-firing fuels used by them are quite different. Among them, cement rotary kilns use the most different types of fuels, including bituminous coal, diesel oil, heavy oil No. 4~6, waste rubber mixture, etc. According to the analysis results of the air pollution fee and the fixed pollution source permit database, the domestic sulfur content of fuel coal ranges from 0.11 to 2.5%, of which 96% of the approved sulfur content values are less than 1% of the coal.
For the characteristics of various types of pollution sources, we tend to target pollution sources such as steam boilers and heat medium boilers in the power industry, circulating fluid bed boilers in the textile industry, rotary kiln in the cement industry and preheating machines and paper-based fluidized bed boilers. In developing the fuel quality standards, it is necessary to consider the domestic use, control impact and necessity, the stage priority is to set the basic specifications for fuel coal. The draft quality standards of fuel coal is sulfur content, ash content and calorific value are 1.0%, 20% and 5,000 kcal/kg, respectively. To evaluate the restriction usage of the materials prone to air pollution, it is referred to the foreign banned substances and the hazardous air pollutants. The regulation about fuel quality standards and co-firing will be set according to the legal source of Article 28 of Air Pollution Control Act. T will be set according to the legal source of Article 29 of Air Pollution Control Act. As so far, we have assess the petroleum coke is banned as fuel, Trichloroethylene and Tetrachloroethylene is banned.
In the future, if the fuel quality standards, such as the upper limit of sulfur content, and the ratio of co-firing are implemented, it is necessary to assess whether the difficulty in obtaining fuels and the procurement cost will be greatly increased, and it is also necessary to consider whether the competent authority could bear the workload and keep the sources operator's operational flexibility. If the authority would like to restrict usage of the materials prone to air pollution, it is necessary to assess the impact on the industry, and take the comprehensive supplementary measures or exclusion clauses.
