Plasma fractionation

Blood plasma is used, among other things, as a starting material for the production of medicines to treat immunodeficiency. The plasma obtained from donors is split into individual proteins – also known as fractions - by means of plasma fractionation. Over 20 different proteins are currently obtained in this way. After separation into plasma fractions, they are purified before being further processed into drugs.

"For consistent separation of the plasma, several process parameters must be precisely controlled", explains Sadiq Khan, director for the IMEA region at Bürkert: “In order to receive pure fractions as efficiently as possible, perfect control of the pH value, ethanol concentration and temperature, among other things, is key.”

Cutting-edge technology meets clever design

The more than 2,000 Bürkert valves used have extremely low tolerances and, thanks to the linear flow characteristic, a remarkably high control quality. But this is not the only reason why they help to keep operating costs low: With their flow-optimised geometry, the valve bodies ensure extremely high flow rates. Compared to conventional diaphragm valves, their kv value is up to 40 % higher. This allows the pumps in the system to operate at a lower speed. As a result, the system operator benefits from energy savings during operation.

In addition to a smooth inner surface, optimised flow paths that minimise dead legs are primarily responsible for the excellent flow characteristics. Improved angles, smooth radii and carefully designed bevels within the valve body reduce product accumulation and make the valves easier to clean. When installed in the correct angle, they are even completely self-draining. Compared to conventional solutions, these innovative developments increase the life of the diaphragm by up to 50 %.

“We quickly realised the value of Bürkert’s long-term experience in the design of fluidic processes. Several thousand valves are used and the skilled valve specialists made sure that each one was perfectly adapted to the specific requirements. They provided us with really good advice,” says DDE Joint Managing Director Ajay Dubey, pleased with the transparent cooperation.

Attention to maximising efficiency was also paid when designing the control cabinets in terms of space requirements and performance: “The experts were precisely aware of the power consumption of all the components involved. This enabled them to realise a very compact I/O distribution and to optimally adapt each rack to our requirements without exceeding the maximum available power.”

Compact valve islands 

Handling ethanol in the course of separation requires explosion-proof components approved for ATEX Zone 1/21 – both for process automation and in terms of valve technology. In addition to the Bürkert valve island type 8647, type 8650 are therefore also used for Zone 1/21. The pneumatically actuated field devices also have the corresponding approvals.

Thanks to the comprehensive interface support of the valve islands, the pneumatic block can simply be attached to the top-hat rail of the PLC and connected to its I/O interfaces. The signals are communicated directly via the fully compatible PROFINET backplane bus.

The seamless integration of the valve islands into the controllers has saved many kilometres of cables and numerous terminals in the locally manufactured control cabinets: “The partnership between Bürkert and Siemens, which has existed for over two decades, has proven its worth here.The space requirement is reduced by up to two thirds with this solution compared to conventional panels. Thanks to our fully integrated solution, the individual control cabinets are also connected to the DCS level with extremely reduced cabling,” says Sadiq Khan. This saves installation work and minimises the risk of errors. The position of the pneumatically controlled field devices is also displayed directly on the associated pilot valve. This increases efficiency during maintenance. “The smart concept with full hardware and software integration of the pneumatic control into the Siemens ecosystem is unrivalled, especially in the Ex area. The resulting space savings and significantly simplified project planning with PCS 7 and the TIA Portal made our decision in favour of the Bürkert solution an easy one,” Ajay Dubey is convinced.

Safety first

DDE’s reactors have a capacity of up to 5,000 litres. Their contents are correspondingly valuable. A loss of a large batch of blood plasma in the vessel would be fatal, as the Joint Managing Director of DDE emphasises: “If the fractionation process is interrupted, the entire product quantity in the reactor is destroyed.“ For this reason, DDE worked with Bürkert to set up redundant CPUs, redundant power supplies and a redundant communication network of each rack via PROFINET (system redundancy S2 with redundant PROFINET configuration). Full integration at hardware and software level also shows its strengths here: Thanks to the combination of the Siemens controller‘s safety functions and Bürkert‘s pneumatic safety functions, safety-related shut-off is possible by module or by channel via PROFIsafe. This reliably prevents failures and maximises yield.

Overcoming challenges with modularity

“Together with Bürkert, we were able to provide our customer with highly reliable fractionation systems on time, enabling them to achieve a very high product yield,” says Ajay Dubey proudly. The modularity of Bürkert‘s valve islands was one of the main reasons for this, Sadiq Khan is convinced of the concept: “There were many design changes, which would normally delay the project by months. However, due to the modularity of our 8650 pneumatic I/O system for Zone 1 applications, we were able to adapt with maintaining the same platform. This is an excellent example of complex project collaboration with DDE, resulting in achieving on-time delivery, project financial budget, and a state-of-theart and future-proof system with the ability to maintain sterility.”