Waste Heat Generation for Cement Kiln Helps Chinese Cement Firm Save 27,000t Coa


For a long time, people are always of such an idea that cement is an energy-intensive and heavy polluting industry. However, with the call of state policies on energy-saving and emission reduction, some cement manufacturers in Beijing have shaken off this status. When we came to Beijing Liulihe Cement Company Ltd ("Liulihe Cement" or "the Company"), a subsidiary of BBMG Corporation, the operators who just off work told us that more than half of mechanical facilities in the Company were operated with electricity generated by heat by-product through cement kiln in manufacturing process.

It's not strange to many people about cement kiln, but to generate electricity by heat by-product in the process is a fresh idea. Mr. Zhao Xiangdong, General Manager of Liulihe Cement introduced the principle of electricity generation by heat by-product is as follows: much heat by-product will be produced in cement manufacturing process, so electricity can be generated by using heat by-product of waste gas discharged from kiln head and kiln outlet. This way can increase the overall thermal utilization rate of cement manufacturing from 60% to above 90%.

"We feel pity for heat by-product being wasted and it also violates our corporate philosophy of circular economy and profit maximization," Mr. Zhao Xiangdong said. A common way of cement kiln heat by-product recycling is to use waste and industrial refuse as a kind of alternative fuel. But seven or eight years ago, cement industry had a common problem of inefficient capacity, and therefore the Company developed a new technology and supporting facilities for electricity generation by heat by-product through cement kiln, which opened up a new way for cement kiln heat by-product utilization.

We saw this "Big Stomach" cement kiln in the Company: together with the roars of machines inside a column-shaped rotary kiln and a hundred-meter high feed pipe standing at one side, a low temperature heat by-product power station was just built on an open space nearby. "Since being put into operation in July 2007, all targets of the power station have achieved design criterion. Our average output reaches approximately 6,000 kilowatt and we are of leading position in China in term of electricity generation index", Mr. Zhao Xiangdong said. Instead of having any negative impact, the organic combination of heat by-product power station and cement kiln system actually is playing a positive role in kiln heat stabilization, which guarantees the quality stability of cement products.

Besides products, the Company also achieved immediate effect on energy-saving and emission reduction. As at the first six months of 2008, the electricity generated by heat by-product accounts for 54.2% of its total power consumption, equivalent to saving 27,000 tons coal a year. Furthermore, thanks to this electricity generation by heat by-product, the dust density of waste gas entering dust separator in kiln outlet is lowered, the emission of flying dust and heat is reduced, and the benefit of comprehensive utilization is also increased obviously.

Nowadays, electricity generation by heat by-product has become a unique technology of Liulihe Cement with independent intellectual property, and has brought significant economic returns through technical services and technology transfer. The Company also signed service agreement with a well-known Chinese energy-saving development company to provide the operation supervision and guidance services of heat by-product electricity generation projects home and abroad.
Source: Beijing Daily
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