PROJECT DESCRIPTION
BACKGROUND
The chemical and petrochemical sector is responsible for more than 30% of total industrial energy consumption worldwide (including feedstocks), making it by far the largest industrial energy user. The phosphate industry is no exception, with demand growing, especially for polyphosphoric acid, from a range of purposes, including for pharmaceuticals, cosmetics, petrochemicals, road construction (asphalt), textiles, water treatment and fertilisers. In 2009, worldwide polyphosphoric acid production reached more than 50 kilotonnes (kT), with an annual growth rate of 4.2%. More than 60% (31.91 kT) of this production is currently achieved via a thermal process (by applying heat), which has a major environmental impact and is very energy consuming.
OBJECTIVES
The LIFE Polyphos Acid project planned to establish a pilot process for the production of highly purified polyphosphoric acid (85% P2O5) using an innovative wet process that is less polluting and more energy efficient. However, it is more complex than the thermal process and as a result it is not as widely used. The wet process consists of transforming phosphate rock into a first intermediate product, the raw acid (60% P2O5), which is then made into purified acid (63% P2O5), which can be finally converted into the purified polyphosphoric acid (85% P2O5).
The project aimed to focus on this last step in the production process, planning to build a pilot-scale facility at the beneficiarys premises. This site would comprise a flame chamber (the first sub-system and also the main innovative element), a second critical sub-system (the mass and energy recuperator), and finally the gas treatment equipment. This new patented process was expected to substantially reduce energy consumption and greenhouse gas emissions, while reducing waste.
RESULTS
The LIFE Polyphos Acid project partly reached its objectives. The installation of the full pilot, which connected the three sub-units, was finalised only at the end of the project, meaning that it did not start producing polyphosphoric acid within the established timeframe. However, the design and construction of the vital sub-units the flame chamber, recuperator and gas treatment unit represent a key outcome of the project, with a prototype silicon carbide (SiC) flame chamber shown to be particularly robust. Furthermore, the project demonstrated the feasibility of producing purified polyphosphoric acid (exceeding the target of 85% P2O5) with the silicon carbide flame chamber connected to the facilities of the pilot R&D.
Life Cycle Analysis LCA, based on tests with the pilot R&D, showed that the innovative wet process will lower the systems overall carbon footprint and reduce energy consumption by more than 80% compared to the most polluting thermal processes currently used.
Delays in the project related to the use of silicon carbide solid material, which has been shown to improve the heat resistance and corrosion of the flame chamberwithout increasing the cost of the system. However, plain silicon carbide is a novel solution and only a limited number of suppliers are able to manufacture the required components and those that do expressed to reluctance to cooperate. Therefore, the beneficiary itself took over this aspect of supply, which delayed the initial schedule.
The prototype recuperator prioritised the recovery of residual acid in hot gases from the flame chamber. Heat recovery should be demonstrable when the pilot is recreated on an industrial scale. The beneficiary is continuing to develop the pilot using its own funds. It is looking to scale up the pilot apparatus to industrial level at its production sites. A pre-industrial business plan was developed and a major stakeholder in the phosphates industry has expressed a strong interested in the project process.
The project addresses the European Commissions Roadmap for moving to a competitive low carbon economy in 2050, as well as the Policy framework for climate and energy in the period from 2020 to 2030. It also shows how to implement aspects of the EU Directives on Energy Efficiency and Waste.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).
