Tai’an Zhongke is a joint venture specializing in MSW (municipal solid waste)-to-energy production. It adopts domestically developed CFB technology (circulating fluidized bed). According to Yan Yong, the plant has two incinerators, with a daily treatment capacity of 1,000-1,200 tons. “Currently Tai’an City produces 500-600 tons of solid waste per day. Now we are digging out garbage that was placed in the landfill in the past. It is estimated that we can dispose of it all within five years, and land once designated for waste can be put to other purposes.

Finding the Goodness

Incinerated garbage shrinks its mass by 90 percent, greatly reducing the land needed by landfills that don’t use this method first. Better yet, the “by-products” of garbage incineration are themselves usable resources. According to Yan Yong, the plant was connected to the State Power Grid when its trial operation kicked off. Its annual power generation capacity is 120 million kwh, with every kilogram of garbage generating 0.4 kwh. The surplus energy can provide winter heating for citizens of the community.

Yan Yong pointed at the residential quarters opposite to the plant and said, “That is Chiziya New Village, inhabited by 800 households. Last winter they used heating provided by our plant. In future we will supply heating to the West Railway Station, Tai’an Health School, and No. 2 Dormitory of the Development Zone.” The incinerators’ low emissions of particles, sulfur dioxide, hydrogen chloride, nitrogen oxide and carbon monoxide meet state standards. A monitoring report revealed that 83.5 percent of the surrounding residents believe the plant does not pollute their environment, and 76.9 percent are satisfied with the environmental protection efforts made by Tai’an Zhongke.

Too Hot to Hurt

CFB (circulating fluidized bed) MSW-to-energy Technology was developed by the Beijing China Sciences General Energy & Environment Co., Ltd (GEE) under the Chinese Academy of Sciences. Jin Jian, general manager of GEE, said, “The core value of this technology is that it is suitable to burn the type of solid waste as that produced in China – unsegregated and low in calorific value.” Jin Jian points out that garbage incineration has been in wide use in developed countries as a ripe resource re-use technology. However, it does not suit China’s conditions, since the components of municipal solid waste tends to be different here. Chinese cooking produces more foodstuff leftovers, whose high moisture content makes it hard to burn. Coal or oil has to be added.

As one of the earliest developers of a China-tailored system, Jin Jian said, “One characteristic of this technology is that it can raise the temperature of garbage to 850 degrees Centigrade in the twinkling of an eye, and keep the temperature of its smoke at this level for three to four seconds.” He further elaborates that, generally speaking, harmful substances such as dioxin are produced at lower temperatures of between 250 and 550 degrees Centigrade, whereas at 850 degrees Centigrade, the conditions for its production don’t exist. “This inhibits the production of pollutants, which is safer than absorbing pollutants using active carbon at a later stage,” added Jin Jian. He said that another characteristic of this technology is its external superheater, which effectively boosts the creation of heat energy for power generation.

A three-day test was conducted at the Tai’an Zhongke to monitor the emission of dioxins from the incinerators. After analysis, the sponsor, the Research Center for Eco-Environmental Sciences of the Chinese Academy of Sciences, found dioxin contents of all smoke samples were lower than both state and EU standards.

Get Cracking

China still lags behind developed countries in garbage treatment technologies, and the new systems China has independently developed are mostly in the experimental stages or in initial promotion. Efforts will not be relaxed.