PHP PLANT PROCESS

- MAIN OPERATIONS

- DESCRIPTION OF UREA PRODUCT HANDLING SYSTEM

- THE PLC SYSTEM WORKING

 

UREA PRODUCT HANDLING SYSTEM TAKES PLACE THROUGH THE FOLLOWING MAIN OPERATIONS :

Urea produced in three urea plants is brought to bagging plant for bagging or diverted to silos with the help of conveyors & flappers. Urea from silos is again reclaimed with the help of scrappers. This urea brought from urea plant & silos, is fed to 19 bunkers with the help of flappers & conveyors. Below the bunkers there are weighing and stitching machines to bag the urea in 50 kg bags. The bagged urea is further dispatched to various locations in the country by Railway & Trucks.

The scheme consists of conveyers and other related equipments to handle urea prills from the urea prilling towers up to Railway wagons/road Truck loading points. The distribution of urea through various conveyors to the bunkers is done by PLC. For the system operation New PLC system

Urea Plant to Silo Area Conveyors & Equipments operation

Scrapper operation & Silo Material Reclamation

Material Distribution & Bunker feeding

Urea weighing, Bag filling & Stitching

Filled Bag handling, Loading & Despatches by Rail & Road

Transport & clearance Procedure

Other Related Activities to Destination

(Programmable Logic Controller) M/S Tata Honeywell make has been installed in the year 2000 for controlled and easy operation .

  DESCRIPTION OF UREA PRODUCT HANDLING SYSTEM

A) UREA PLANT TO SILO AREA CONVEYORS & RELATED EQUIPMENTS OPERATION:-

1 There are three plants of Urea namely 11, 21 and 31.Each having capacity of 1725 MT. per day. Urea prills are received on conveyor ET-1 a, b, c (For 11, 21, 31 respectively) from the prilling tower bottom, This material forwarded to the conveyor ET-2 and ET-3 through grizzly manuted two way chute BC-1 a,b,c. The oversize urea prills carried by conveyor ET-2 a,b,c, finally goes to three separate urea dissolving tanks. Continuously belt weighed WM-1 are installed on conveyor ET-3 a, b, c to get continues weighment of product. Conveyor ET-3 a, b, c discharges either on to the conveyor ET-4 or conveyor ET-4R through two way discharge chutes BC-3 a,b,c respectively.

2.Transit Conveyor ET-4 / ET-4R (one is stand by):- They carry the

product from urea plants conveyors ET-3a,3b,3c to Transfer tower No.1 (near silo-I) and the material is discharged through 2-legged chute (BC-4 or BC-4R) either to storing conveyor ET-6 for storing in silo No.-I or two take off conveyors ET-11/1 and ET-12/1 towards the plant. Some time product is to be diverted to the Silo No.-II for storing purpose through chute (BC 4.2 or BC 4R.2) interconnecting conveyors ET-5 and ET- 5R respectively. Conveyor ET-5 and ET-5R carry the product to transfer tower No.2 and discharge it on conveyor ET-7 of silo No.-II, Either ET-4 and ET-5 or ET-4R and ET-5R remain in operation when product is taken to Silo No. II for storage.

3. Storing Conveyors ET-6 and ET-7: To carry the material from ET-4/4R to silo-I & Silo-II respectively. These conveyors are equipped on both the sides with of 3-way chutes, for discharging the material in silo along its length.

4 Tripper: ET-6 and ET-7 are equipped with movable leveling trippers. It is having three way chutes, which discharges the material on both sides of conveyers, along the length of silos.

5 T.T.-I BC-4/4R sliding chutes: In the year 2004 two sliding chute for ET-4 and ET-4R were separately installed on Transfer Tower-I from top floor to ground floor. The ET-4 has a BC-4, 4.2, 4.3 & ET-4R has BC-4R, 4R.2 ,BC4R.3. The material falls through these chutes on ET-11/1 & ET-12/1 conveyors

B) SCRAPPER OPERATION & MATERIAL RECLAMATION:-

The Urea from silos is reclaimed by salt scrappers.

1. Salt Scrapper: Urea stored in silos is reclaimed by means of traveling salt scrapers. MH2a and MH2b in the silo-I & silo-II respectively. Scraped urea is discharged on conveyor ET-8 and ET-9 respectively. It is huge machine to reclaim the urea from silo. It is provided with motorized movements like Traveling, Scrapping, Bucket elevator , Discharging Conveyor, Hoisting & lowering , Laffing. The toothed Scrapping boom is collections the urea from the heap and takes it to base of scrapper & which is lifted through the Bucket Elevator and discharged on conveyor of scrapper and it falls on conveyor ET-8 & ET-9 of I & II silo. The Scrapper is Elecon make.

2. Reclaiming conveyers ET-8 & ET-9 : Material reclaimed from silo-I & II scrapper is carried through carrying conveyor ET-8 &9 to TT-I & TT-II respectively. In TT-I & TT- II towers, material is discharged on the bagging plant take off conveyor ET-11/1 and ET-12/1 directly through two way chute BC-8 and BC-9 . Here Trapped iron pieces are extracted out from reclaimed material with the help of electromagnet EM 1a and EM 1b and permanent magnetic pulley (head pulley) of conveyor ET-8 and ET-9. This arrangement helps us to keep away the iron pieces from product.

3. Dozer: Dozer is used for collecting the spread off material in the silo. It is also used for Cleaning of Scrapper track.

C) MATERIAL DISTRIBUTION & BUNKER FEEDING :

1. Transit conveyors ET-11/1 & ET12/1: These conveyors carry material from silo Transfer towers TT-I & TT-II to BPT-I. The conveyors ET-11/1 & ET-12/1 are used for taking the material to the plant in the North & south side separately each series. In the plant 21 Bagging stations are distributed in three series and having seven machines each .And slat 15 ,19 in the third series are now defunctio. Out of that 7 machines 4 machines are in the North and 3 machines are on the south side. These three series are connected by three Transit conveyors of Bagging plant Towers I, II & III namely ET-11/1, ET-11/2, ET-11/3 for feeding material to north & ET-12/1 & ET-12/2, ET-12/3 for feeding material to south side. The conveyor ET-11/1 discharges material either on conveyor ET-11/2 or to First series conveyor ET-13/1.1 and similarly conveyor ET-12/1 discharges material either on conveyor ET-12/2 or conveyor ET-13/1.5 with the help of two way Flapper chute i.e. BC. From BPT-II ET- 11/2 feeds to Conveyor ET-13/2.1 or conveyor ET-11/3 & 12/2 feed to 13/2.5 & ET-12/3 these further discharges on conveyor to third line conveyors ET-13/3.1 similarly south conveyor ET-13/3.5 by means of chutes.

2. Transfer Tower conveyors ET-13 & ET-14 : First conveyor of each series

i.e. ET-13 carrys the discharged material from B.P.T.-I, II, III & feeding the material to the first station or slats & forwarded to next conveyor ET-14 for feeding to Each next bagging station or Bunkers (slats) sequentially.

3. Bunker : The fed Urea is stored in Bunkers of capacity 15 MT each. The stored material is passed gravitationally through pipes to weghing Machine hoppers for weighment.

D) UREA WEIGHING, BAG FILLING & STITCHING:

1. Weighing & Bag filling operation : The Speedac 7 is a microprocessor based weighing machines includes load cell weight sensors for the automatic, high speed dispensing of pre-determined loads of bulk material into bags or bulk containers.

For the operation weighing controller of make M/S Chronos Richardson

India Ltd. of U.K is used. The weighing system comprises of a controller and a weigher. We are having stand-alone weighing system for each of the 19 weighing machines in Bagging Plant. In the operation proper 50.00 Kg material weighing is achieved. The operation is also very simple.

The material drops into the weigh hopper gravitationally from the bunker. The material flow is controlled with the help of the catch gate; having a window. The catch gate remains completely open, till the material weight in the hopper reaches the ‘FULL FEED’ setting ( approx. 35 Kg). After that the catch gate is closed partially and the material flows only through the window provided to the catch gate. This helps maintaining the accuracy of the weighment. When the material in the hopper is sensed as 50 Kg by the load cells, the catch gate is completely closed. If the bag is clamped on spout after pressing the switch the hopper door gets opened and material is discharged in the bag. After that the hopper door gets closed and next cycle starts. All these operations are controlled by the pneumatic air (Air Pressure is 5-7Kg/cm2g).

The weigher comprises of a weigh hopper, the load cell weight sensor and Gravitational material feeding system. The discharged filled bag of weight 50 Kg being of urea is carried forwarded to the stitching by the flat-belt ET-16.

4. Stitching Machine ET-16 operation : The filled bag carrying conveyor ET-16 has forward and reverse operation for the movement of bag. The forwarded bag is stitched by Stitching Machine with the Yarn or thread in the single Row or double Row. Now DS-9A New long Machines are using for single Row Stitching & AV-205 Gabber Engineering stitching machines are used for Double Row stitching .

E) FILLED BAG HANDLING & LOADING:

The stitched bags are carried by ET-16 conveyor and are forwarded through two way chutes BC-16 to either East side or West side of each of platforms No. 11,12 of the first series, 12 and 13 for the second series and 13 or Truck loading point from the third series. The two way chute BC-16 delivers the bags on the platform through sliding chute to the Transfer conveyors ET-18 . There are total eight ET-18 conveyors i.e. ET-18/1.3, ET-

18/1.4. ET-18//2.1, 2.3 for 12 p/f & ET-18/2.2 , ET-18/2.4 , ET-18/3.1 & ET-18/3.2 for the 13 no.p/f .

Sliding chutes are provided for the loading of Trucks. In addition to normal loading on the Machine number 20 (m/c3.6) this machine can be utilized for filling of T.G. urea in 500, 700 Kg. Jumbo bags. This bulk loading operation is utilises funnel type chute made up of s. s. pipe.

Bag Divertor Trolly : For the loading of wagons on platform is done with the help of Movable Divertor Trollys are placed on ET-18 conveyors for each machine, which discharges the bags on platform through chute BC-18 on the loading platform at height of 4.5 feet for manual lifting of filled bags and loading of wagon. Platform conveyor ET-18 have been separated in south & north side of the platform, one receiving from North and other from south.

The bags discharged from divertor chute is lifted by Mathadi manually on head and loaded directly to the wagons or trucks .

F) TRANSPORT AND CLEARANCE PROCEDURE ( T & C ) : 1) Railway Procedure : i) Empty wagons arrival : From NGSM, Kalyan, Panvel. Roha route

ii) Wagons examination of arrived wagons i.e. TXR & releases only fit Wagons for loading.

iii) Placement : Only fit wagons are placed and sick wagons are send to

sick siding for making fit for loading.

iv) Loading Completion : Free 9 hours are given for loading and 2 hrs. are given for shunting from the placement time, after 11 hours if the supply is not completed demurrage is charged .

v) Sealing completion: After completion of loading, sealing is done by railway commercial staff .

vi) Load formation: After sealing of loaded wagons , load will be formed in yard by our shunting Staff. Loaded wagons are of two different station, then accordingly load will be formed on two separate lines. vii) Handover to TXR : After load formation, it is handedover to TXR for Examining the loaded wagons (line block)

viii) TXR Released: After examining the load, TXR gives us report whether load is safe or unsafe. If load is safe, then only Railway engine is Placed on that load.

ix) Engine on : This is to increase break - power for break system, through vacuum point.

x) Load dispatch : After developing pressure, load is dispatched.

2) Yard :

a) No. of lines in yard : * Line ‘A', ‘B', and ‘C' i.e. total three lines. * Line No.1 to line no. 8 i.e. total 8

* Platform lines are three, i.e. 11,12,13. * Track no. 5 is for Sick siding. * Track no. 4 is for Ammonia siding . * Track no. 14 is for loaded sick.

b) Classification of lines : * Arrival lines -- 1, 2, 3, and 4 * A- Napatha , B- coal , C- Engine reversing line. * dispatch lines -- 5, 6, 7, and 8 * Sick siding lines - where sick made fit for loading and dispatch. * Ammonia siding lines - where ‘BITAL' are filled/ Unloaded. * line – 14 no. use for loaded sick fit and T.P. wagons.

G) GENERAL :-

1) Empty Bags Management:

* Empty bags first received in receipt godown & stacked zone wise. * After third party sampling bags goes to NDT testing in plant i.e

Appearance, colour, stitching quality , length, width etc. & DT Testing to Central Lab for strength, quality etc. * With the help of third party sampling is done and 100 bags are drawn randomly i.e 50 for NDT & 50 for DT.

* Receiving the bag report & NDT report OK. bags will shift to the Issuing godown. * Daily consumption (requirement) of empty bags is above1 lacks bags. * Empty bag weight is 0.130 kg. * Weight of filled bag is -- 50.130 kg. 2) Truck loading : (dispatch)

Urea is also transported by trucks. In truck, only 10 to 12 MT of Material is carried. (i.e. 200 to 240 bags) Therefore, it is not possible to transport the whole production by trucks and also transporting cost is more. Mostly trucks are loaded at slat No. 16,17 ,18,19, 20.

3) Wagon loading : (Dispatch)

There are different types of wagons used for loading i.e. BCXN,BOX, BCN , BCNA. BCNHS, Now a days only BCN, BCNA ,

BCNHS are mostly used.

SR.NO WAGON TYPE

CARRYINGCAPACITY (MT)

NO.OF BAGSLOADED

1 BOX 52 TO 54 1000 TO 11002 BCXN 55.5 11073 BCN 60 11964 BCNHS 61 12165 BCNA 63 12566 BTAL 32

Wagons are to be loaded within 9+2 hours. This time is for placement,

sealing , Removal & shunting of wagons (free hours). After 9+2 i.e. 11 hours it causes `Demurrage' which is the extra charge to be paid to railway. i.e. Rs.100/= per hour for one BCN, BCNHS , BCNA wagons . If only single wagon of a particular platform will go under ‘demurrage' than all the wagons on that platform will causes demurrage, even the remaining wagons are filled within time.

 

THE PLC SYSTEM WORKING:

1) Control changed from hardware to software ease to Modify logic.2) Ease of operation from PC desk.3) Better control on feed: with start to finish & finish to start Selection4) Better flapper Control due to operation from Desk. (Additional Facility like two position flapper operation can be done)5) Per Shift Bagging, Urea Trip, Silo diversion, Silo reclaim data is Available.6) Belts on with material, without material and off position is visible.7) Ease of faultfinding including ease in maintenance.8) Percentage bunker level indication is available.9) Timers provided to bunker feed.10) Remote mode of operation available.11) Current measurement of all motors up to 5.5KW is available.12) Additional current protection is provided to motors.13) Additional ZSS provided to ET 4,4R main motors.14) No. of bags through the sliding chutes is displayed (This can be reset for new placement)