What pressure / is your tankers rated at?

What kind of tanker tipping or belly?

What kind of air mover are you going to use?

Normal tanker rated at 2bar with onboard 2 bar compressor and this conveying route will unload within an hour. ■

In my Handbook of Pneumatic Conveying Engineering (Marcel Dekker) there is comprehensive data on the conveying of OPC through a 50 m long pipeline of 4 inch NB with 9 ninety degree bends. For a pressure drop of 30 psi and 200 cfm of free air you get a flow rate of about 70,000 lb/h, with the cement conveyed at a solids loading ratio of about 70. So with your shorter pipeline with fewer bends you should be able to offload 28 tonnes in 40 to 45 minutes. ■

Dear Sir,

Calculating your system, using a compressor of 6m3/min at 2.0 bar gives:

Pressure discharge Cement

Convey length = 37 m

Nu of bends= 6

Pump vol = 0 1 + 0 1 m^3/s

q-convey = 0.10 m^3/s

Dia begin = 95 mm

Dia end = 95 mm

Kettle volume = 50.0 m^3

Cement vol.= 26.0 m^3

Kettle Cement content = 28.6 tons

Pipevolume = 0.26 m^3

-----------Pipeline-------------- Syst

Press-------Cap-----. mu------Cap. . v-begin---- v-end--- kWh/ton ----res.time

2.000 ------40-------- 88--------28 -------6.0 ------16.9 ----- 0.44---------- 5.53

1.750-------37--------81--------26 --------6.5-------16.8------0.43-----------5.29

1.500 -------33-------74--------25 --------7.0 ------16.7 ------0.42-----------5.05

1.250--------29-------65-------22 ---------7.7------16.6-------0.41----------4.80

1.000--------25-------56--------20 --------8.6 -----16.5 ------0.40---------- 4.51

0.750------- 20-------45--------16--------9.7 ------16.4 ------0.41--------- 4.24

0.500--------14-------32--------12 -------11.2-----16.3------ 0.47----------3.92

0.250------- 6.7------15---------6 -------13.3-----16.1-------0.73--------- 3.60

Empty pipeline pressure ...= 559. mmWC

Unloading time, including pressurizing time of a 50 m3 bulk tank is 1 hr (28 tons/hr)

Pressurizing time 16 minutes

Discharging time 43 minutes

Silo content = 100 m3 # 140 tons

Filling time will be approx 140/28 = 5 hrs

best regards ■