www.howden.com/compressors
HOWDEN THOMASSEN COMPRESSORS Custom built compressor systems for polysilicon applications
thomassen compressor SYSTEMS clean room manufacturing
Purpose built to provide the purity and volume that OUR CUSTOMERs’ need
^ We have taken the greatest care to design, manufacture and assemble a compressor that runs without introducing any impurities into H2 processing. We put just as much effort into ensuring that it leaves our workshops free of any contaminants or foreign particles.
^ We have built a dedicated clean room area within the factory for the assembling of the compressor cylinders. Within the clean room, all of the internal surfaces of the cylinders are meticulously inspected, and even the most minute roughness is polished off to eliminate areas where deposits might collect. The cleaning processes are carefully matched to the materials being worked, but typically include: • dust removal, • degreasing, • jet washing to remove chemicals, • drying with clean nitrogen gas, • acid pickling, as well as • essential washing and drying.
^ Before the unit leaves the clean room, all the internal areas are flushed with a volume of nitrogen gas many times greater than the internal volume of the compressor. Finally, the compressor is filled up with pressurised nitrogen and all openings are sealed to ensure that the unit arrives on site in the same contamination-free condition that it is despatched from the factory.
Polysilicon is in growing demand for applications in solar cells and semiconductors, and in both applications the need for purity is exceptional. Solar cells require polysilicon at a purity of 99.9999%. Electronic applications demand a purity one hundred thousand times greater even than that. It is obvious that the manufacturing process demands superlative standards of cleanliness and process integrity, and it follows that the hydrogen used in manufacturing polysilicon also has to be of the highest purity. In the past, when the volumes required were smaller, diaphragm compressors could be used in the H2 production process because they offer complete, hermetic isolation of the process gas. Today, however, we need more production than low-capacity diaphragm compressors can cope with.
Now, Howden Thomassen has engineered a heavy-duty, horizontally-balanced reciprocating compressor that provides the high volume, ultra-high purity H2 processing that the polysilicon industry depends on.
Rsens™ sensor to provide exceptionally accurate feedback on the condition of the rider rings. The sensor, which has been tested in the most severe conditions, is actually placed inside the cylinder head cover from where it transmits information, accurate to within 0.1mm, about the real-time clearance between the piston and the cylinder wall. This is far more precise and reliable than the traditional method of measuring piston rod drop from outside the cylinder. Howden Thomassen uses double-compartment distance pieces in the compressors, allowing a double buffer and vent system to ensure that no air or inert gas can come into contact with the process gas. The section at the cylinder end is buffered with H2, and the part at the crosshead end with inert gas. The pressures and venting systems ensure that a high level of separation is maintained between the two gas streams, so the process H2 is buffered by a separate volume of pure H2, and all flange packings are selected to meet the special requirements of the polysilicon production process.
Purity with flexibility Polysilicon manufacturing is a batch process. Even where multiple Chemical Vapour Deposition units are used in a single process line, it can be necessary to adjust the volume of H2 being introduced. The most energy efficient way of doing this is to adjust the compressor capacity as it runs. The Thomassen Hydropocket allows efficient and accurate adjustment to be carried out remotely, and it has the great advantage of achieving this without any need to add a capacity controller to the suction valve, a technique that reduces efficiency and has the potential to impair the operation of one of the most critical, high-maintenance areas of the whole compression process.
For further information about Howden Thomassen Compressors for the polysilicon industry, please contact: Tel: Web:
+ 31 (0) 26 4975200 www.thomassen.com
thomassen compressor SYSTEMS clean room manufacturing
Purpose built to provid d volume that OUR CU
^ We have taken the greatest care to design, manufacture and assemble a compressor that runs without introducing any impurities into H2 processing. We put just as much effort into ensuring that it leaves our workshops free of any contaminants or foreign particles.
^ We have built a dedicated clean room area within the factory for the assembling of the compressor cylinders. Within the clean room, all of the internal surfaces of the cylinders are meticulously inspected, and even the most minute roughness is polished off to eliminate areas where deposits might collect. The cleaning processes are carefully matched to the materials being worked, but typically include: • dust removal, • degreasing, • jet washing to remove chemicals, • drying with clean nitrogen gas, • acid pickling, as well as • essential washing and drying.
Polished Cylinder
^ Before the unit leaves the clean room, all the internal areas are flushed with a volume of nitrogen gas many times greater than the internal volume of the compressor. Finally, the compressor is filled up with pressurised nitrogen and all openings are sealed to ensure that the unit arrives on site in the same contamination-free condition that it is despatched from the factory.
Free Floating Piston (FFPTM)
Polysilicon is in growing demand for applications in so d in both applications the need for purity is exceptio Solar cells require polysilicon at a purity of 99.9999%. Electronic applications demand a purity one hundred thousand times greater even than that. It is obvious that the manufacturing process demands superlative standards of cleanliness and process integrity, and it follows that the hydrogen used in manufacturing polysilicon also has to be of the highest purity. In the past, when the volumes required were smaller, diaphragm compressors could be used in the H2 production process because they offer complete, hermetic isolation of the process gas. Today, however, we need more production than low-capacity diaphragm compressors can cope with.
Now, Howden Thomassen has engineered a he ed reciprocating compre that provides the high vo tra-high purity H2 pr that the polysilicon indust depends on.
Eliminating the sources of impurities The compressor, based on Howden Thomassen’s long history and specialist experience of making reciprocating compressors, has been developed through a process of investigating and methodically eliminating the sources of wear that create extraneous particles and allow them to enter the process gas. Oil-free operation is essential, to eliminate the possibility of a lubricant contaminating the process gas. In the past, however, this has led to high levels of wear in the rider rings and cylinder packing elements, producing particles that enter the gas. Howden Thomassen’s patented Free Floating Piston (FFP™) technology introduces a cushion of process gas that supports the piston and eliminates all contact between the rider rings and the cylinder lining during normal operation of the compressor. Because there is no wear, there is no possibility of particulate matter entering the process gas. The FFP™ system has a number of ancillary benefits. It removes the need to replace rider rings, and with it one of the major causes of maintenance outages. Experience has shown that it also leads to more stable behaviour in the packing elements, once again minimising wear.
RsensTM Sensor
For absolute peace of mind, we can add our patented Rsens™ sensor to provide exceptionally accurate feedback on the condition of the rider rings. The sensor, which has been tested in the most severe conditions, is actually placed inside the cylinder head cover from where it transmits information, accurate to within 0.1mm, about the real-time clearance between the piston and the cylinder wall. This is far more precise and reliable than the traditional method of measuring piston rod drop from outside the cylinder. Howden Thomassen uses double-compartment distance pieces in the compressors, allowing a double buffer and vent system to ensure that no air or inert gas can come into contact with the process gas. The section at the cylinder end is buffered with H2, and the part at the crosshead end with inert gas. The pressures and venting systems ensure that a high level of separation is maintained between the two gas streams, so the process H2 is buffered by a separate volume of pure H2, and all flange packings are selected to meet the special requirements of the polysilicon production process.
Purity with flexibility Polysilicon manufacturing is a batch process. Even where multiple Chemical Vapour Deposition units are used in a single process line, it can be necessary to adjust the volume of H2 being introduced. The most energy efficient way of doing this is to adjust the compressor capacity as it runs. The Thomassen Hydropocket allows efficient and accurate adjustment to be carried out remotely, and it has the great advantage of achieving this without any need to add a capacity controller to the suction valve, a technique that reduces efficiency and has the potential to impair the operation of one of the most critical, high-maintenance areas of the whole compression process.
For further information about Howden Thomassen Compressors for the polysilicon industry, please contact: Tel: Web:
+ 31 (0) 26 4975200 www.thomassen.com
www.howden.com/compressors
Passion for Compression Howden Thomassen Compressors BV is a leading international supplier of innovative, high-quality compression equipment to the world’s most vital process industries. Since 2011, it has been part of the global Howden organisation, the world’s leading supplier of fans, compressors, blowers and rotary regenerative heat exchangers. Recognised and respected for leading edge design and the highest standards of engineering, Howden has companies based in 17 countries, combining a local level of service with access to world-class expertise and unrivalled experience. Everything we manufacture is backed by a lifetime commitment to spares, aftermarket services and advice on upgrades and retrofits.
Howden Thomassen Compressors Havelandseweg 8-a PO BOX 99 6990 AB Rheden The Netherlands Tel: + 31 (0) 26 4975200 Fax: + 31 (0) 26 4975201 Web: www.thomassen.com
Howden Thomassen Compressors BV is a member of the Howden Group of companies.
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