After 40 years in the business.....

What type of refinery are you talking about? Aluminium refineries import calcined coke whereas heavy crude oil refineries produce green shot coke.

If it is calcined then there will be a dust problem and if it is green there will be a water problem (most pits are poorly drained) and wet coke might avalanche during the ascent and then there will be real blockage.

Study the existing specs from eg TKI and develop a formal enquiry to suit the type of coke involved. For this exercise you will need the help of a pipe conveyor manufacturer or some other expert. The sentence on drive requirements indicates that you must seek paid help, for starters.

Fluor Daniel are one of the top engineering establishments worldwide, you are there, so why not ask them? ■

Mr. Chander,

Dos Santos International would like to look at your requirements and offer you assistance. Please forward your project information to www.dossantosintl.comwww.dossantosintl.com

SKYPE ID: adosduncan ■

Originally Posted by Author

Dear Subash Chander

I can help you with this pipe conveyor, as my company now is doing many conveyor project tender in India for up to 6km length,and our installation have more than 4km for

3000t/h ore.

Please do send to me your email so we can share more information of the pipe conveyor, it is really very flexiable solution and could suit your requirements.

Tks!

Dai Yuanjun

daiyuanjun@libochina.cn

skype:babaydai

I can help you with this pipe conveyor, as my company now is doing many conveyor project tender in India for up to 6km length,and our installation have more than 4km for

3000t/h ore.*

Please do send to me your email so we can share more information of the pipe conveyor, it is really very flexiable solution and could suit your requirements.*

Tks!

Dai Yuanjun*

daiyuanjun@libochina.cn*

skype:babaydai ■

Dear Mr Subhash

For a 2km long conveyor, with both horizontal and vertical curves, with lift in the order of 35 m and capacity of 1200 tph of coke conveyor can be designed with Drive at head end or with drive at both Head/tail end .

Tail end drive is provided to reduce the belt maximum tension similar to conventional conveyors . You can select Lower rating belt by providing tail end drive .

In case you send me profile of the conveyor We can offer you suitable details

A R SINGH ■

Dear Mr. Chander,

One key factor in designing longer pipe conveyors is the drag force of the empty belt. This typically constitutes about 60-70% of the operating power. As such, you can see that the return strand can drag up to 50% of the carry, when empty, for a horizontal running conveyor. Thus, the load often only adds about 30-40% of the total power required. However, in your case, the lift force constitutes about 19% of necessary power.

Given the high return drag, in many cases, it may be prudent to apply a tail drive, depending on total power and savings in belt vs. adding tail drive station together with complication of control and maintenance. However, 2 km and 1200 t/h is not likely to need a tail drive.

Your system may require about 900-1000 kW. At best, a tail drive split would be 250 kW. This means you drop the belt strength from ST-1000 to ST-800 N/mm. You must add a drive. Is it worth it?

You need a good pipe conveyor engineer to give you this insight. An optimized conveyor may do better.

CDI has installed 90 km of pipe conveyors to date. Longest length is > 8 km, highest power 4500 kW, strongest belt ST-3150 N/mm, with head and tail drives. We often recommend the Goodyear Confine construction to control seam stability. ■

Hello Shri Subash Chander,

One has to make preliminary design to decide whether to have drive at head end alone or whether to distribute it between head end and tail end.

If it is manual exercise, find carrying run resistance Rc and return run resistance Rr. Accordingly total resistance will be Rc + Rr. The first possibility for distribution is:

A) At head end: Rc / (Rc + Rr) as a fraction of 1.

B) At tail end: Rr / (Rc + Rr) as a fraction of 1.

If B) value is very small (less than say 0.2), then you may find it not worth to have drive at tail end. In any case, the decision is governed by total cost (mechanical + electrical + structural + civil) for option - 1 versus option - 2. The structural implication will be insignificant and can be ignored. The civil can add some price if cable etc. are to be buried / trenches, etc.

However, if there is functional requirement to have bare minimum tension (say least tension at concave radius of S/R machine in case of conveyor, or not to have too stiff a belt in context of particular diameter of pipe conveyor), then the designer do opt for drive at both the ends, irrespective of monetary aspect, provided it results in reduction of belt tension, to fulfill technical need.

Nowadays such exercise can be done easily by entering data into conveyor design program having provision for multiple drive. The drive number and their location is a major decision. Hence it is better to design for few alternatives, and then choose the best option considering economy and performance (which also include belt behavior for pipe conveyor).

The example mentioned by you has 35 m lift for conveyor. This lift will introduce negative slope resistance for return run, which will reduce Rr and in turn possibly dilute the case for tail end drive.

The reply / information is somewhat elaborate so that less expert readers can also understand.

Ishwar G. Mulani

Author of Book : Engineering Science And Application Design For Belt Conveyors (new print November, 2012)

Author of Book : Belt Feeder Design And Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916

Email: www.conveyor.ishwarmulani.comwww.conveyor.ishwarmulani.com ■

Hello Mr. Chander,

It's not easy to tell the number and position of drive in your conveyor, without the plan & sectional profile of the conveyor. Profile of a pipe conveyor plays a vital role for the proper functioning of conveyor and more that 50% erection/commissioning/running problems can be eliminated with a good conveyor profile.

You have mentioned, the conveyor has a 35m lift. Is it the maximum lift or nominal lift? Does the conveyor have any declined/regenerative portion in carrying side? All this to be considered to calculate effective belt tension and then drive distribution to be done in such a way that belt rating should be minimum with minimum amount of take-up weight.

In the return run, if the conveyor have declined in nature then the belt tension at tail pulley shall be lower than the belt tension at drive pulley return side and the same shall be higher in case of horizontal conveyor. this point also to be considered before putting drive at tail pulley.

thanks & regards,

Sajal Chakraborty

Material Handling Consultant

sajalweigh@rediffmail.com ■