Pharmaceutical water special information

Pharmaceutical water special information

 

Design of Storage and Distribution System for Pharmaceutical Water

 

First, the slope of the pipe

 

Piping design should be appropriate for the laying of pipelines to consider the appropriate slope to facilitate the drainage of the pipeline. That is, the pipe must be installed so that all the water in the tube can be drained. This requirement should be identified as a design parameter in the system. Pharmaceutical water system piping drainage gradient is generally taken 1% or 1cm / m. This requirement applies to pipelines for purified water and water for injection systems. Piping system, if there is water, must also set the water discharge points and valves. It should be noted, however, that the number of drainage points must be as small as possible.

 

Second, the allocation of water distribution pipe parameters

 

The amount of water used in the pharmaceutical process is determined by a variety of conditions depending on the process, the nature of the product, the performance of the pharmaceutical equipment, and the water resources in the area where the pharmaceutical is located. By analyzing the use of water for each water point to determine the use of water.

 

Often, the calculation of process water consumption is carried out according to two main water conditions. (Ie, the maximum (or peak) water consumption and the maximum (or peak) water use time in the production process); the other is based on the consumption of units in the unit The average amount of water used on the product (this water includes auxiliary water) is calculated. Regardless of which algorithm is used, the demand for the production process water should be taken into account and should be uniform and uniform throughout the entire production cycle of the drug manufacturing. At the same time, it should be considered as possible to adapt to the development of production and the possible future expansion of the water system.

 

To meet the various needs of the process, the design of the pharmaceutical process water consumption is based on the specific varieties of the drug in the production process of direct water consumption and the indirect process of indirect water and the decision. That is, in considering the specific varieties of production and production arrangements in various factors, according to the above process distribution pipeline design principles and requirements to determine the specific principles. And its calculated water consumption by the day of the production process of the peak amount and the average amount of comprehensive determination. Different drug production process, the water consumption of the situation is very poor.

 

2.1 production process water points and water consumption standards

 

The water consumption in the process water system is related to the degree of perfection of the water treatment equipment used, the technological process of the drug production, the situation of the water resources of the production area. Often, the change in process water is relatively large. In general, the more water the process water, water treatment equipment, the more perfect, the less the uneven water every day.

 

The use of pharmaceutical water due to the use of various water use conditions are different, very different. As mentioned above, the process water system is divided into multiple water points, only high temperature water point or only low temperature water point, both high temperature water point and low temperature water point, different water temperature water point, both use A variety of water temperature situation, there are times when the use of different water temperature, and so on. Therefore, it is difficult to simply determine the water use situation at the water point. It is necessary to determine the storage and distribution of the pharmaceutical water system before the design calculation to determine the maximum instantaneous water consumption on this basis. Then, according to the process of the maximum instantaneous water consumption to calculate.

 

The maximum amount of water used in the process of the standard, according to the annual production of pharmaceutical production, according to the specific time of each day to determine the amount of water to determine the process to determine the amount of water should be set in the process of water tank capacity adjustment.

 

2.2 System design flow to determine

 

Design process water pipes need to determine the diameter of the pipe and the loss of water by hydraulic calculations. Its main design is based on the design of the pipeline through the design of the second flow value. Design seconds to determine the flow of the amount of water needs to consider the actual situation, the amount of water changes and the impact of factors.

 

Usually, the flow rate is determined by the simultaneous use of all water points. According to the production line of water equipment to improve the degree of design of the second flow:

 

Q = Σn q max c

 

Where q - the design of the process factor seconds flow, m3 / s;

 

N - water and water equipment data;

 

Q max - the maximum water outlet, m3 / h;

 

C - water use coefficient at the same time, usually choose 0.5-0.8.

 

2.3 Design flow inside the pipe

 

Pharmaceutical water is a type of fluid, it has the general characteristics of the fluid. When the fluid flows in the pipeline, the volume flowing through any section per unit time is called the volume flow. And the velocity of the fluid inside the pipe is the distance traveled by the unit per unit of time. The delivery speed inside the pharmaceutical water pipeline is closely related to the hydrodynamic characteristics of the system. Therefore, for the particularity of pharmaceutical water, the use of water hydrodynamic characteristics, the appropriate selection of distribution pipelines within the water flow rate, for the process of water system design is essential.

 

The main difference between the hydraulic calculations in the pipeline and the water calculation in the general feedwater pipeline is that the hydraulic calculation of the pharmaceutical water system should carefully consider the specific requirements of microbial control for hydrodynamic characteristics in the water system. Specifically in the pharmaceutical water systems are increasingly used in a variety of disinfection, sterilization facilities; and the traditional one-way DC water supply system into a series cycle.

 

These differences provide a series of significant changes in the design and installation of hydrodynamic systems for pharmaceutical water systems: for example, to control the microbial retention within the piping system and to reduce the likelihood of microbial growth.

 

To this end, the US Pharmacopoeia on the pharmaceutical water system in the state of the water flow made a clear request, hope that the process of water in the "turbulent state" under the flow. It is necessary to understand the specific significance of the use of the "turbulent state" concept by understanding the characteristics of the US Pharmacopoeia by understanding the hydrodynamic properties.

 

In general, the velocity of the fluid is not the same at each specific point in the cross section of the pipe. The flow rate is the largest in the center of the pipe at the center of the pipeline. The closer the tube wall is, the smaller the flow rate is. At the point close to the pipe wall, the flow rate is equal to zero due to the attachment of the fluid mass to the inner wall of the pipe. The flow velocity inside the industrial fluid piping is available for reference with the following empirical values:

 

(1) the general liquid flow in the pipeline when most of the use of less than 3 m / s flow rate, for the viscous liquid selection of 0.5 ~ 1.0 m / s, in general, the selected flow rate of 1.5 ~ 3 m / s;

 

(2) low-pressure industrial gas flow rate is generally 8 ~ 15m / s, higher pressure industrial gas was 15 ~ 25m / s, saturated steam flow rate can choose 20 ~ 30

 

M / s, and the flow rate of superheated steam can be selected from 30 to 50 m / s.

 

The type of fluid motion can be observed from the Renault experiment. On the basis of the experimental results obtained from different fluids and different diameters, it is proved that the fluid flow through the diameter of the conduit d, the density ρ of the fluid and the viscosity of the fluid, in addition to the flow rate q of the fluid, The type of fluid flow is determined by dqρ / ц. This value is called Reynolds number, denoted by Re. According to the Renault experiment, the flow of fluid in the pipeline can be divided into parallel flow (stagnation) and turbulence in two cases.

 

It should be noted that the Reynolds number is a pure value, there is no unit, and therefore is the number of reasons. In the calculation, as long as the unit is consistent, for any unit can get the same value. For example, in the meter kilogram - second system Renault quasi-unit of the unit:

 

(Kg) s (m / s) (kg / s2 / m4) / (kg / s / m2) = (m) 0 (kg) 0 (s0)

 

Where all units can be eliminated, leaving the value of the fluid flow type. And the same result can be obtained when using ruler-pound-second English. The Reynolds experiments show that when the Re value is less than 2300, the fluid flows in a stagnant state. If the Re value is greater than 2300, the state of the fluid flow begins to change to turbulence. It should be noted, however, that the transition from stagnant to turbulent is not abrupt, but rather through a transitional phase, which is usually referred to as a transitional stream with a Re value from 2300 to 4000 , Sometimes can be extended to more than 10,000. Thus, only when Re is equal to or greater than 10000, stable turbulence can be obtained.

 

The state from turbulence to turbulence is called the critical condition, and generally the critical value of 2300 is Re. It should be noted that this critical value is related to many conditions, in particular the fluid entry, the wall roughness and so on.

 

It can be seen that in the pharmaceutical water system, if only the flow of water inside the pipeline is not enough to emphasize the necessary conditions to control the pollution of microbes, only when the Reynolds number Re of the water flow process reaches 10000, when the steady turbulence is formed, It can effectively cause environmental conditions that are not conducive to the growth of microorganisms. Since the molecular weight of the microorganism is much larger than the water molecular weight, even if the flow rate at the tube wall is zero, if the turbulence has been formed, the microorganisms in the water will be in an unavoidable environmental condition. On the contrary, if there is no special attention to the design and construction details of the water system during the design and installation of the pharmaceutical water system, the flow rate is too low, the pipe wall is rough, the result of the existence of a dead water pipe section, The microstructures are not conducive to the control of microbial valves and so on, the microbes are entirely possible to rely on the resulting objective conditions, in the process of water system piping on the inner wall of the accumulation of microbial film, resulting in microbial contamination of pharmaceutical water systems.

 

(1) stagnation

 

When the fluid flows inside the pipe, each fluid mass stably flows in an orderly fashion in a direction parallel to the center of the tube axis. This flow is called parallel flow (laminar flow) or viscous flow, referred to as stagnation. When the fluid is in a stagnant state, the velocity is distributed along the diameter of the pipe along the parabola. At this point the center of the pipeline the largest speed along the curve asymptotic wall, the speed gradually smaller to zero, the average speed of the tube center speed of half.

 

(2) turbulence

 

When the fluid flows inside the pipeline, the fluid particles do not move in the same direction, but are irregularly curved. The velocity of each particle changes in size and direction with time, and the movement traces between the fluid particles are extremely disturbed Flow lines are easy to change the flow known as turbulent or turbulent flow, referred to as turbulence. When the fluid is in a turbulent state, the curve shape is similar to the parabola, but the top is slightly wider. Due to the collision of the fluid particles in the turbulence, the flow rate changes in size and direction, and tends to an average. Therefore, the more turbulent state, the more flat the top of the curve, when in a very stable turbulent state, the average speed of the tube center of the maximum speed of 0.8 to 0.9 times.

 

According to the above description of the velocity distribution inside the pipe, even if the fluid is indeed turbulent, there may still be a layer of stagnant boundary layer near the tube wall. This boundary layer actually includes the real stagnation layer and the transition layer. In the real stagnant layer, the velocity of the fluid decreases approximately linearly, and the velocity at the pipe wall tends to zero. The transition layer is between the real stagnant layer and the fluid body. The thickness of the boundary layer is a function of the Re number.

 

Thus, there is no mere turbulence in the fluid flow and there is no pure stagnation. In fact, there is a stagnant layer in the turbulence, and there may be turbulence in the stagnant flow, because some of the fluid particles in the stagnation of the deformation and rotation of the phenomenon. The existence of fluid boundary layer, its heat transfer and diffusion process will have a great impact.

 

The above-mentioned flow velocity distribution means that the flow of the fluid has reached a steady state. Fluid into the pipeline after the need to flow through a certain distance, the stability of the state can really be formed. For turbulence, experiments show that the straight pipe distance flowing through it reaches 40 times the pipe diameter, the stable state can be obtained.

 

In addition, the distribution of velocity only in the isothermal state is established, that is, the temperature of the points in the fluid is consistent, constant

 

2.4 Resistance calculation of pipelines for pharmaceutical water systems

 

According to the use of water points in the water, according to the use of water points in the pipeline, first draw the system pipe network axis mapping, and then according to the design of the pipe network in the second flow, according to the flow of pharmaceutical water should be in turbulent state, that is, Pipe water velocity is greater than 2m / s requirements, calculate the pipe diameter, pipe resistance loss, and then determine the process water system required transport pressure, select the water pump.

 

(1) to determine the water pipe diameter

 

After calculating the flow rate of each pipe section in the axle chart, calculate and control the flow rate according to the following hydraulic formula, select the diameter:

 

Di = 18.8 (Qg / υ) 1/2

 

Where di - the inner diameter of the pipe, m;

 

Qg - design of each pipe section seconds flow, m3 / s;

 

Υ - tube flow rate, m / s.

 

In general, the diameter of the pipe is determined by the economic flow rate within the system. As can be seen from the above equation, once the flow rate is determined, the diameter of the corresponding flow is naturally obtained. Piping fluid resistance, for the same flow, the larger the diameter, the smaller the loss of resistance. This is economical in terms of power, but the cost of the equipment will increase and may not meet the requirements of the turbulence of the process water system.

 

Pharmaceutical process pipeline to meet the microbial control of the flow rate of 2 ~ 3m / s.

 

(2) to determine the pressure loss of the pipe section

 

① process water system pipe along the resistance loss

 

Py = K L

 

Where

 

Py - process loss of process resistance, m H2O;

 

L - the length of the calculated pipe section;

 

K - pipe unit length of the pressure loss, in accordance with the pharmaceutical water pipeline is usually made of stainless steel, piping internal flow rate greater than 2m / s, you can use the following formula:

 

K = 0.00107 × υ2 / d1.3 (m H2O / m)

 

Υ - average velocity of pipelines, m / s;

 

D - pipe calculation diameter, m.

 

In general, the pressure loss of the straight pipe can be calculated using K = 0.007 × (m H2O / m).

 

② local loss of pipeline

 

Pj = Σξ (υ2 / 2g)

 

Where Pj - the sum of the local resistance losses, m H2O;

 

Σ ξ - the sum of the local resistance coefficient, according to the process of water system pipes in the different pipe fittings and the structure of the valve accessories have a variety of different values;

 

Υ - along the direction of the flow, the local resistance downstream of the flow rate;

 

G - gravity acceleration, m / s2.

 

In the calculation of the local resistance of the pipeline system, it is usually not possible to carry out a detailed calculation, and the percentage of resistance loss along the line is often 20%.

 

(3) Loss of resistance of the pipe joint resistance The loss of the pipe joint depends on its size and type, calculated using the value of ξ. The pipe joint resistance coefficient is shown in Table 5.1:

 

Table 5.1 Resistance loss of fittings

 

Diameter / mm203250 ≤ 63

 

Pipe joint type Resistance coefficient ξ

 

Round elbow 1.51.00.60.5

 

90 ° elbow 2.01.71.10.8

 

45 ° elbow 0.3

 

T-type connector 1.5

 

Entrance 0.5

 

Exit 1.0

 

④ pipe pressure loss, the following two formulas:

 

Σ △ р = Σ △ рy + Σ △ рfi + Σ △ рva

 

Where the resistance of the total ducts;

 

Рy - the resistance along the pipeline;

 

Рfi - resistance of pipe joints;