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Energy Conservation in Pharmaceutical Manufacturing
As pharmaceutical manufacturers face an increasingly competitive environment, they are looking for opportunities to reduce production costs without negatively affecting the yield or the quality of finished products. Energy-price volatility can negatively affect financial performance. The challenge of maintaining high product quality while reducing production costs can be met through investments in energy-efficient technologies and energy-efficiency practices. Energy-efficient technologies may offer additional benefits, such as quality improvement, increased production, and improved process efficiency, which can lead to further productivity gains. Energy efficiency also is an important component of a company’s environmental strategy because energy-efficiency improvements can lead to reductions in pollutant emissions. Because energy use varies across manufacturing segments given differences in unit operations, process principles, and equipment, it is difficult to address energy-saving measures in broad manufacturing terms. This articles examines opportunities to conserve energy in pharmaceutical manufacturing operations through currently available products and concepts.
Opportunities for energy efficiency
Management decisions regarding energy-saving measures should be passed on to the bottom layer of the organization. Programs that include regular feedback on staff behavior, including rewarding those incorporating rewards, have had the best results. Though changes in staff behavior (such as switching off lights or closing windows and doors) often save only small amounts of energy at one time, taken continuously over longer periods, they can have a much greater effect than other, more costly technological improvements.
Energy-management systems and programs
Energy-conservation measures can be implemented at any time, but it is better if optimizing energy use is considered from the early-concept stage. The benefits of considering energy-efficiency early include:
Electric motors.In a typical pharmaceutical plant, electric motors are a key component of almost all the equipment including reactors, centrifuges, air oven dryers, vacuum dryers, and blowers. Significant attention should be given to proper maintenance and operation of the motors. In the case of burnt-out motors, many operators prefer to do a rewinding or repair job and reinstall the motor without checking its efficiency/electricity consumption. Very often re-winded or repaired motors consume energy at a very high rate, and the running cost of the old motor becomes more than that of the cost of a new one.
Cooling towers.Cooling water treatment is mandatory for any cooling tower, whether it be splash fill or film-type fill, to control suspended solids and algae growth. With increasing water costs, efforts to increase cycles of concentration (COC) can help reduce water requirements significantly. In large industries, such as power plants, COC improvement is often considered a front-line tool for water conservation.
Cooling tower fans. The purpose of a cooling tower fan is to move a specified quantity of air through a system, overcoming the system resistance, also described as pressure loss. The product of air flow and pressure loss is air power developed/work done by the fan; this may be also termed fan output. Fan input (kW) depends on fan efficiency, which is in turn greatly dependent on the profile of the blade. An aerodynamic profile with optimal twist andtaper and a higher coefficient of lift to coefficient of drop ratio can provide the fan with a total efficiency as high as 85–92%. However, this efficiency is drastically affected by the factors, such as tip clearance, obstacles to airflow, and inlet shape. Because metallic fans are manufactured by either extrusion or casting processes, it is difficult to generate the ideal aerodynamic profiles. Fiber reinforced plastic (FRP) blades are normally hand-molded, which generates the optimal aerodynamic profiles to meet specific duty conditions more efficiently. Cases have been reported where replacement of metallic or glass fiber reinforced plastic fan blades with hollow FRP blades yielded fan energy savings on the order of 20–30% with a payback period of six to seven months. Also because they are lightweight, FRP fans need less starting torque, thereby allowing lower horsepower motor to be used. The lightweight design also increases the life of the gear box, motor , and bearings and allows for easier handling and maintenance.
Steam traps. In process heating, more than 60% of the thermal energy used is in the form of steam. Process improvements to steam generation and more efficient use of steam can conserve large amounts of energy. One reason fuel and steam conservation opportunities can be so significant is because multiple system improvements can be made. Collectively, these changes can yield savings of 10-15% in many cases, with a general project payback period of less than two years. Steam traps should be inspected to determine whether they are functioning properly or allowing live steam to blow through. Programs for periodic inspection and maintenance of traps with correct reporting should yield savings. Typically, high-pressure traps should be inspected at least twice a month, medium-pressure traps once every two months, and low-pressure traps every six months. Plants in which traps have not been inspected or maintained for three years or more could have up to 30% of their traps blowing steam. This level could be brought down to less than 5% with a well-designed and executed maintenance program.
Lighting options. Lighting is an essential part of operations. If energy conservation is considered at the design stage, lighting and ventilation costs can be reduced. The plant can be designed in such a way that proper lighting is maintained throughout the day. Windows or transparent glass can be positioned through walls and roof tops to maximize natural light. Employees also can be trained to be partners in energy-saving efforts, and individuals can be rewarded for exceptional conservation behavior. Adding technologies, such as light sensors that automatically switch lights on and off, will also help yield long-term energy savings. Because incandescent lamps convert just 5% of energy, with the remainder given off as heat, fluorescent lamps that turn 25% into light should be used wherever possible. These lamps also use less electricity and have a longer life span compared to incandescent lamps. Conventional fluorescent lighting systems operate from the mains using a simple series choke as the ballast, which creates sufficient voltage with the glow starter to both start the lamp and to limit the lamp’s current afterwards. Another energy-saving lighting solution is to replace the conventional magnetic ballast with electronic ballasts, which are more efficient and compact. This approach can save up to 20-25% of lighting cost wherever used. Similarly, old fan regulators should be replaced with electronic regulators to minimize the energy usage. Table I compares the performance of a conventional ballast with an electronic ballast. The drawback of the electronic ballast is the price, which is typically several times higher than its magnetic counterpart.
Table I: Comparisons of the conventional and electronic ballasts for T8 36W fluorescent lamp.
Light-sensitive electronic ballast systems with the intelligence to sense outdoor light are now being used for many commercial buildings. The systems use a light sensing device to feedback ambient signals to a micro controller that adjusts the operation frequency of the inverter in the ballast. The light output is thus adjusted automatically according to the sunlight.
Agitators. Agitators are an essential part of process equipment. Advances in technology have enabled new agitators that consume less energy without compromising product output and quality.
Example 1: Ekato Viscoprop. The benefits of using an Ekato Viscoprop agitator in place of a pitch-blade turbine include:
The Ekato agitator is more useful when the reaction mass or mixture consists of more than one phase, for example, heterogeneous mixtures where uniform mass distribution is needed. Uniform mass distribution is especially important in bioreactors where there is considerable biomass formation during the fermentation process and the availability of nutrients to the microorganisms is vital for productivity. The Ekato agitator ensures better mixing and uniformity of mass and power savings when compared to a standard turbine impellor. This agitator has been used successfully for the production of fermentation products such as lovastatin using 30 m3 bioreactors. Increased output and reduced energy quickly pays back the agitator cost. With varied impellor designs, it is also possible to reduce capital expenditures by optimizing the shaft diameter. Table II compares a pitch-blade turbine with Ekato Viscoprop.
Table II: Comparison of a pitch-blade turbine with Ekato Viscoprop.
Example 2 Lightnin A-315 Agitator
The Lightnin agitator has been used successfully for various fermentation products where there is considerable biomass generation and the solids content may be up to 40-50%. This agitator also has the unique advantage of low shear stress, which helps in maintaining the integrity of the biomass and facilitating downstream processes. When used for the production of salinomycin in a 100 m3 bioreactor, the Lightnin A-315 agitator contributed to energy savings of up to 25% and increased productivity.
L. ShamKishore is technology transfer officer, K. Manmadha Reddy is executive, technology transfer, and A. Kumar Pathy is deputy manager of technology transfer with Neuland Laboratories.