In a series of articles, we explore waste management in China. In this third article, we look at how China Resources Cement has beaten unique difficulties of waste incineration with a new pyro co-processing facility based on the FLSmidth HOTDISC® system.
Former articles in the series:
• Scaling China's waste mountains
• Can the Chinese cement industry help contribute to waste management?
China Resources Cement beats unique difficulties of waste incineration with a new pyro co-processing facility based on the FLSmidth HOTDISC® system.
Waste incineration in China presents unique challenges. Its high level of water content and other organic substances means it typically delivers low calorific values, which makes it difficult to produce sufficient energy for energy-hungry processes – including cement production.
So when China Resources Cement (CRC) saw an opportunity to integrate urban and industrial waste into its cement production processes at its 3200 tpd Hongshuihe plant, it needed to find technology specifically suited to handle the raw waste’s characteristics.
Reducing municipal waste
The opportunity arose from the growing need for manufacturers to contribute to waste reduction. Located in Binyang, a city in the Guangxi region, Southwest China, CRC’s Hongshuihe plant is one of approximately 40 cement production lines owned by CRC in mainland China. In September 2014, CRC signed an agreement with the Binyang Government to help reduce the city’s waste.
But even before then, CRC had begun investigations into different suitable technologies and equipment. This included evaluating FLSmidth’s HOTDISC® combustion solution, and early in the process, CRC commenced detailed technical inspections and discussions with FLSmidth. Eventually, CRC concluded that a HOTDISC solution would be the best solution and that FLSmidth was the only company that could supply such a solution.
FLSmidth was asked to supply its HOTDISC combustion device as the key equipment for the co-processing system and to provide engineers to assist with onsite installation and commissioning.
CRC’s trust in FLSmidth was also influenced by its considerable previous experience with FLSmidth equipment in operation at CRC plants, including 13 ATOX® raw mills and 28 rotor weighfeeder Pfister® TRW-S. Confident in FLSmidth’s ability to contribute to the project, they started mapping out a plan for combining bio-mechanical pretreatment and combustion in a HOTDISC system.
A local engineering consultancy, SEPEC, was brought into the project as general contractor, responsible for coordinating resources and preparing the engineering plans. In addition, a local design institute planned the waste pretreatment processes, such as waste storage and transportation. Together, the partners worked closely together to build a safe, reliable and technologically advanced facility, which was constructed and commissioned in less than a year.
CRC had originally wanted the largest HOTDISC system available, but this was impossible because of the limited space in the preheater tower. Instead, it was decided that a mid-sized HOTDISC system of type HDR63-315 would be trialled.
Following preliminary work beginning in September 2014, construction of the facility commenced in January 2015, with production starting up in December later that year. The tight schedule – which included installing the burner as quickly as possible to minimise production stoppage – and a steep learning curve were achieved through excellent teamwork between the three partners, featuring regular meetings to review the solutions being developed.
The presence of FLSmidth’s technical experts meant that any immediate problems could be quickly solved. Within FLSmidth, the Chinese Project Management team, led by Zhou Lun, was responsible for executing the project in close collaboration with colleagues in Denmark, India and the US.
Following production start in December 2015, the waste incineration system was tested extensively over a six-month period, during which it successfully handled 50,000 tons of municipal waste. One of the most important success criteria was the system’s ability to meet emission limits, which are the strictest to be enforced under Chinese law.
Of particular focus, explains Zhou Lun, Project Manager for FLSmidth’s team, was the HOTDISC solution’s ability to handle the physical characteristics of Binyang’s municipal solid waste (MSW), which featured high moisture (ranging from approximately 40 to 70 percent) and low calorific value (less than 1500kCal/kg). In other countries, it has successfully incinerated refuse-derived fuel (RDF) with quite different characteristics.
“The HOTDISC solution has successfully combusted RDF in many other installations, which often includes materials such as old tyres, but this was the first time it had to dispose of typical Chinese MSW, which is not pre-sorted and is high in water content and low on energy. It was exciting adapting the HOTDISC solution to be able to handle this kind of waste.” - Zhou Lun, Project Manager for FLSmidth
During testing, it became clear that the HOTDISC solution could run efficiently with the Chinese MSW and deliver stable, reliable operations.
Zhou Lun explains: “It achieved a waste feed rate of more than 300 tpd, which actually exceeded expectations and matches the kiln’s capacity.
The production system was not adversely affected, and the plant could maintain the same quality and quantity of clinker. And importantly, emission levels were contained within the strict limits, which showed it can deliver reliable environmental protection.”
Following the period of testing, the system was officially inaugurated on 28 June 2016. Per Mejnert Kristensen, Group Executive Vice President at FLSmidth is pleased with the success of this groundbreaking project, noting that it has caught the attention of local government officials.
He says that it marks two important breakthroughs: the first HOTDISC system installed in China and the first application of a HOTDISC solution in handling raw municipal waste.
Management of CRC is also satisfied with the outcome, with Mr Yu Baoguo, General Manager of the CRC Hongshuihe plant commenting, “The outstanding performance of the HOTDISC system from FLSmidth is key to the great success of the whole project.”
“With the HOTDISC solution as the core equipment, the project’s success proved we made the right choice in the first place, and we will be working closely with FLSmidth in the future.” - Mr Zhang, Vice President of CRC
Positive environmental impact
CRC’s new co-processing facility already has a positive impact on Binyang’s environment, helping to scale back the garbage mountains by an estimated equivalent of 0.75 hectares per year and reducing methane emissions by 8.76 million cubic metres a year. The aim had been clear, says Zhou Lun: “The key to CRC’s co-processing project was environmental assurance and safety.”
All environmental impact indices show impressive levels. All of the ash residue and pretreated waste can be used as alternative fuel and materials in cement production processes, and the process generates no solid waste or secondary pollutant emissions.
Emissions of air pollutants are within national limits, and some indices, such as dioxin emissions, perform significantly better than EU emissions limits. The facility also meets all odour control standards and the sewage treatment and water discharge is in full compliance with local environmental requirements.
This project is not only helping to rid the city of its waste problem; it has also proven itself to be an important energy source at CRC’s Hongshuihe plant. With it, CRC has taken a major step towards environmental protection while paving the way for sustainable development within the cement industry.