Coal Mill.ppt

COAL MILL EQUIPMENT Operation Area (s) Category Presented by Date

We Build Our Future Enterprise based Vocational Education

: Coal Mill Grinding : Equipment : Jefri Gunawan : 15 May 2018

Content or Agenda  Nama, Fungsi, dan Cara Kerja Alat  Jenis-Jenis/Macam-Macam Alat

 Parameter Operasi Alat  Komponen Kritis  Problem-Problem yang Sering Terjadi

 Proses Maintenance  Material Coal

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Coal Mill Equipment

15 May 2018 Jefri Gunawan

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Coal Mill Equipment

15 May 2018 Jefri Gunawan

Vertical Roller Mill (VRM) - 3 Bagian Transport Exhaust gases Raw meal

1. Pemisahan



Drying

Separation

Feed Material

Grinding

2. Penggilingan 

Drive

3. Penggerak 

(Drive)

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Hot gases

Energy



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VRM - Material Flow inside Separator:

Gas & Product Material

Memisahkan

material halus

Umpan Material

Rejects

material kasar Internal

gas flow

Separator Rejects Internal Circulation Material besar ke scraper Material Material & Gas Gas 5

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Proportioning (feeding) Provide homogeneous raw coal mix

 Raw coal show a typical cohesive property  The feed bin must be designed for mass flow  Ideal capacity of a feed bin is 3 Hours of continuous operation!  Same precautions as per raw material

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Drying

gases* (only noninert)

~…m3/h

In Roller Mills  higher drying capacity

Product with < 1% H20 …or hygroscopic equilibrium reached

 Cooler hot

~… m3/h

 Kiln gases

System Coal with 0 – 20 % H20 For higher moistures  pre-drying is NECESSARY!!

Heat sources

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Grinding - Material Circulation Mill Exit / Fine Coal

NO recirculation bucket elevator!!

Raw Coal Feed

Hot gas

Table rejects

e.g. FLS ATOX Coal Mill Enterprise based Vocational Education

Coal Mill Equipment

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15 May 2018 Jefri Gunawan

VRM – Prinsip Kerja Roller Vertical roller mill Kekuatan Grinding = Berat Roller + (Pressure) kekuatan Roller

menggelinding dengan bebas di table

Ketebalan Material

umpan material

Table bergerak oleh drive

Feed size: f (Roller Ø ) Enterprise based Vocational Education

Coal Mill Equipment

9 15 May 2018 Jefri Gunawan

Beberapa Fungsi Equipment di Bagian Grinding Mengontrol material

roller

yang meninggalkan tempat penggilingan Airspeed yang melalui

nozzle ring mengontrol jumlah material yang grindingmeninggalkan table

dam ring

bed

Mengontrol

ketebalan material

nozzles table

Armour ring: linermengontrol

jumlah material yang balik ke table Enterprise based Vocational Education

Coal Mill Equipment

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Recomendasi Fineness Coal

HGRS Standard Recommendation:

 Coal: 

% R90μm <= ½ * (% volatiles)



% R200μm <= 1%

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VRM - Built-in Separator separator Staticstatic type

conventional rotor type Conventional

cage rotor type Cage Rotor type with guide vanes P

P

Rotor type

F

T

F

F T

P

T F F

F

P

Separation

T

control: 1. Vane adjustment 2. Speed control TF Enterprise based Vocational Education

FT

Coal Mill Equipment

F=

Feed

P=

Product

T=

Tailings

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LV Technology Classifier

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Coal Mill Equipment

15 May 2018 Jefri Gunawan

LV Technology Classifier

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Coal Mill Equipment

15 May 2018 Jefri Gunawan

LV Technology Classifier

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Coal Mill Equipment

15 May 2018 Jefri Gunawan

Konsep dari LV Classifier LV Classifiers digunakan untuk vertikal mill dan ball mill. LV Classifier rata-rata menaikan produk lebih banyak 10 – 20 % dan mengurangi konsumsi energi sekitar 1.5 – 5 kwh/ton dibandingkan dengan separator yang lain. 1. LV Pocket Kekhususan konstruksi dari LV pocket sebagai penangkap material kasar. Material kasar terbawa oleh gas dari mill dan dicegah tercampur dengan material yang halus Material kasar ditangkap oleh LV pocket diturunkan ke corong kerucut tanpa tercampur dengan yang halus. Konstruksi ini menjadikan tak ada material halus tercampur kasar dan sebaliknya. Material di tabel menjadi lebih kecil halus porsinya vibrasi mil menjadi rendah.

2. Funnel Cone Kerucut corong tidak hanya mengupulkan reject dari LV pocket memasukan material ke table tetapi juga mengontrol kecepatan distribusi gas diantara casing classifier dan kerucut corong. Hal ini membuat kemungkinan kecepatan gas lebih baik dan mengurangi sirkulasi internal material. Kehilangan tekanan gas menjadi kecil oleh pengurangan internal sirkulasi material.

3. Funnel Chute Reject dari kerucut corong mengumpan balik ke tengah mil. Kekhususan kerucut corong didesain untuk mengumpan material ke tabel lebih perlahan dengan ketinggian minimum. Hal ini juga menyumbang perubahan vibrasi mil 16 Enterprise based Vocational Education

Coal Mill Equipment

15 May 2018 Jefri Gunawan

LV Classifier Konsep separasi ini untuk memperbaiki laju gas dan matreial di Vertical mill dengan :

• Keunikan desain guide vanee – LV pocket • Keunikan desain rotor • Desain grit funnel Konsep ini berdasar ide:  Memperbolehkan material dilangsungkan ke classifier oleh optimasi kecepatan gas  Menghindarkan material lembut kembali ke tabel dan exces material sirkulasi di dalam mill karena instalasi LV pocket

 Mengurangi kehilangan pressure di mill dan separator. Akibat dari penurunan dari internal sirkulasi material 17 Enterprise based Vocational Education

Coal Mill Equipment

15 May 2018 Jefri Gunawan

VRM - Separator Fotos

Angle affects

product sizing Rotor speed affects

product fineness

Rotor seal affects

separator efficiency 18 Enterprise based Vocational Education

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VRM – Beberapa Jenis Configurasi Mill

Type : coal mill CC1

G.Pfeiffer

Type : coal mill CC2

Loesche

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FLS Atox Coal Mill Equipment

Polysius

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Jenis-Jenis Sistem Penggrindingan 

Non - inert





  



 

Inert





Oxygen content >14% Hot gas from cooler or hot gas generator Temperature and CO monitoring required Simple system / layout Higher safety risk Not for fuel with > 26 % volatiles content Oxygen content < 12% Hot gas from preheater Low explosion and fire risk -> safety Solution for various solid fuel types (petcoke, coal, lignite) Temperature, O2, CO monitoring required

For new installations  Inert system is MANDATORY! Enterprise based Vocational Education

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Mill Dimension Series- Drive Specification

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Mill Dimension Series- Drive Specification

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Specific Energy Consumption vs. Moisture

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Specific Energy Consumption vs Coal Grindabilty § Espec in function of grindability and coal meal fineness § Grindability according to Hardgrove Index (HGI) § Example based on Espec of ATOX coal mill

 hard Enterprise based Vocational Education

soft  Coal Mill Equipment

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Kinerja Coal Mill CC2 Cilacap Plant

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Komponen Kritis - Main drive, clutch, dan Gear drive

- Sistem Lubrikasi - Part-part grinding(table, roller, nozzle, dam ring) - Bearing, roller bearing, bearing sealings

- Air locks, sealing air system for bearings - Hydraulic Pressure System termasuk akumulator

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Coal Mill Example Flowsheet

 Titik Pengawasan : 1.Gas Flow

2.Perbedaan pressure

/Differensial 3.Suhu/temperatur 4.CO dan O2

Safety Quality & Process 31 Enterprise based Vocational Education

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Sistem desain & pertimbangan keamanan Tindakan pencegahan khusus yang harus di buat untuk mencegah 2 kondisi :  Spontaneous Combustion (Self-Ignition Without a Spark)  Explosion (Self-Ignition or Direct Source, e.g. Spark)

Combustible Combustble

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Ignition Ignition source source

Oxygen Oxygen

Tindakan Pencegahan Khusus yang Diperlukan



OPEN STORAGE FOR RAW COAL



RAW COAL BIN



COAL GRINDING & DRYING SYSTEM



DUST COLLECTOR FOR COAL GRINDING SYSTEM



PULVERIZED COAL BIN

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OPEN STORAGE FOR RAW COAL  Meminimalkan waktu penyimpanan  Menyeragamkan lapisan di pile  Ketinggian pile tidak melebihi 6 m  Memonitor hot spots  Mengosongkan BC transport sebelum stop

RAW COAL BIN § Menggunakan desain mass flow bin § Menggunakan lapisan besi anti karat untuk bagian kerucut bin

§ Pernapasan bin § Menjaga bin tetap penuh untuk meminimalkan perpindahan udara 34 Enterprise based Vocational Education

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COAL GRINDING & DRYING SYSTEM §

§

Rekomendasi yang digunakan dalam sistem tertutup untuk pengeringan dan penggilingan

LIGNITE (% by Volume)

LOW VOLATILE COAL (% by Volume)

Start-up interlocking of mill motor

12% O2

14% O2

Operational interlocking of mill plant (to be activated at approx. 120 sec. after start of mill plant)

10% O2

12% O2

Operating alarm

8% O2

10% O2

Menjaga temperatur outlet miil yang aman 35

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§

Pengurangan kehalusan produk dengan peningkatan VM

§

Bagaimanapun jangan pernah kurang dari 20 % di 90 m 36

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§ Desain semua duct, chute dan spout handling fine coal harus berkemiringan 70 %

 Gunakan explosion vent di outlet duct dari Mill 37 Enterprise based Vocational Education

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§

Mengoperasikan terus coal meal transport sistem  Min 2 jam setelah Coal mill Stop

§

Menutup semua sistem selama stop panjang  Dengan Raw Meal

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DUST COLLECTOR FOR COAL GRINDING SYSTEM 

Gunakan explosion vent



Hilangkan flat spots di dalam Dust Collector



Ground bags untuk mencegah spark



Gunakan minimum kemiringan 70º untuk hopper

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§ Isolasi Dust Collector  Gunakan Inlet and Outlet Dampers § Monitor inlet & outlet temperature § Monitor hopper temperature § Monitor differential ‘CO’  Dust Collector Outlet vs. Preheater Outlet § Connect CO2 system to bag area & hopper § Operasikan terus cleaning sistem  Min 2 jam setelahCoal Mill Stop

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PULVERIZED COAL BIN § § § § §

Gunakan mass flow design Gunakan explosion vent Monitor temperature Monitor O2 & CO Inert the bin  Untuk stop mendadak

§ Kosongkan bin  Untuk stop terencana

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VRM- Operasi Roller abnormal / Feed terlalu banyak

Feedrate terlalu tinggi

VIBRASI

Roller akan mulai ‘jump’  Vibrasi 43 Enterprise based Vocational Education

Coal Mill Equipment

15 May 2018 Jefri Gunawan

VRM- Operasi Roller abnormal / Feed terlalu sedikit Feedrate terlalu rendah  Vertical roller mill Material akan

“menggelombang” di atas rotating table

Vibrasi

Table

Roller akan mulai ‘jump’ => VIBRASI

Feed size: RESIKO KERUSAKAN YANG SERIUS !!! Ø) f (Roller Enterprise based Vocational Education

Coal Mill Equipment

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VRM- Operasi Roller yang Normal  Stable Material bed

No Vibrations

Feed size OK

Ukuran partikel maksimum feed adalah: 5-8 % dari

roller diameter Utk roller dgn diameter 1m: Ukuran Max feed 50-80 mm 45 Enterprise based Vocational Education

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15 May 2018 Jefri Gunawan

VRM - Accessories Rotary valve

Pendulum valve Mengurangi false

Mengurangi

air yang bersamaan masuk dgn material.

false air. Baik untuk

Baik untuk material

material yang basah.

kering dan berukuran kecil.

Weigh belt

Metal extraction Material logam

Weighs (timbangan) yang dilewati

material untuk lebih meyakinkan ketebalan umpan didalam mill

akan merusak roller & table. Magnet akan menangkapnya. 46

Enterprise based Vocational Education

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VRM - Control & Maintenance Control  Gearbox

- Vibration monitor - Temperature monitor

 Gas flow

- Temperatures & pressures

 Hydraulics

- Pressures

Maintenance  Wear

- Rollers & Table

- Separator (sealing) & Housing - Liners, fan blades, chutes, dll  Lubrication & Hydraulics (filters and seals) Enterprise based Vocational Education

Coal Mill Equipment

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4 1 / 9 2 8 / 2 0 2 0

INSPECTION  Operasi roller mill yang berkelanjutkan hanya dapat

dicapai jika area area kritis diservis dan diinspeksi secara teratur.  During operation: - Vibrasi pada gear drive dan mill casing - Bearing dan temperature oli - Sistem Lubrikasi 

During stop: -

Part part yang aus (table, roller, nozzle, dam ring) Bearing, roller bearing, bearing sealings Air locks, sealing air system for bearings System Lubrication (Filter, Kondisi oli) Hydraulic Pressure System termasuk akumulator Gear device, clutch. 49 Enterprise based Vocational Education

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Inspeksi visual bagian dalam Mill Pola keausan Mill housing

Pola keausan dan geometri Separator cone

Posisi dan geometri Feed chute

Grinding tools ROLLERS Material, current / expected lifetime, initial weight, net wear, state (cracks, etc.), fixation TABLE  Material, current / expected lifetime, initial weight, net wear, state, fixation

Pola keausan dan geometri Nozzle dan armour rings

Tinggi dan geometri Dam ring

h

Keadaan Scrappers, tumpukan material

Level dan penyebaran material

Material yg melekat di atas table 50

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Separator / Inspeksi Visual

Dynamic seal

3

Guide vanes: Posisi dan pola keausan Enterprise based Vocational Education

Rotor plates: Pola keausan dan fixation 51 Coal Mill Equipment

15 May 2018 Jefri Gunawan

Casing and man hole reparation at Coal Mill (L62 RM1)

Leakage at casing (Rocker Arm)

After repaired Enterprise based Vocational Education

Coal Mill Equipment

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Casing reparation (NDT check and welding) and Man Hole replacement at Coal Mill Bag Filter (L62 BF1)

NDT test by penetrant

Old man hole

New man hole

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Jenis-Jenis Coal Lignite Lignite adalah batubara muda biasanya digunakan di industri semen yang mempunyai kandungan volatil > 40 % dan diperlukan penanganan khusus selama penyimpanan/persiapan untuk bahan bakar untuk mencegah kebakaran dan ledakan calori valuenya rendah dari batubara yang lainnya

 Hard coal Hard coal adalah batubara yang umumnya dipakai di industri semen. Kandungan Volatil normalnya berkisar 18 – 28 %. Batubara ini harus digiling lebih halus daripada lignite

 Anthracite Anthracite coal adalah batubara tua. Batubara ini hampir tidak mengandung volatil dan harus digiling lebih halus dari hard coal dan lignite. Batubara ini tidak mudah terbakar.

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Kandungan terpenting di batubara  Calorific value

 Elementary analysis (influences flame properties)  Ash content (influences clinker chemistry)  Volatiles content (influences ignition and burnout)  Grindability (influences mill throughput and specific energy consumption for grinding)

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Kandungan terpenting di Batubara Kandungan:

     

Calorific value Elementary analysis Ash content Volatiles content Fineness at burner Grindability

Pengertian:



Calorific value menggambarkan berapa banyak energi atau panas yang yang dilepaskan selama proses pembaka ran dalam jumlah yang pasti Ada dua Calori value : 1. Gross calorific value (termasuk panas yang dilepaskan dari pengupan air )

2. Net calorific value (tidak termasuk panas dari penguapan air ) normal yang digunakan di industri semen Enterprise based Vocational Education

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Kandungan terpenting di Batubara

Anlisa dasar memberikan gambaran elemen dari batubara  Elemen utama:

Carbon: C Hydrogen: H Oxygen: O Nitrogen: N Sulfur: S  Kandungan yang tinggi akan carbon dan hidrogen akan

mempengaruhi tingginya calori value  Tingginya ratio carbon terhadap hidrogen membuat

radiasi api lebih baik dan transfer panas dari api ke material lebih intensif 58 Enterprise based Vocational Education

Coal Mill Equipment

15 May 2018 Jefri Gunawan

Kandungan terpenting di Batubara Ash content penting untuk komposisi kimia clinker, semenjak abu

bahan bakar menyatu dalam clinker dan merubah komposisi kimianya Volatiles membantu penyalaan, oleh karena itu kandungan volatil

mempunyai pengaruh yang besar terhadap kehalusan Kehalusan bahan bakar diperlukan untuk menjamin kesempurnaan

terbakarnya batubara. Untuk coal dan petcoke optimum kehalusan : % residue 90 micron = 0.5 x % volatiles residue 200 micron should be less than 1 % Grindability, ketepatan Hardgrove indek memberikan informasi tingkat kesulitan dalam penggilingan (mempengaruhi penyelesaian dan electrical energi ). HGI dibutuhkan dalam proses penggilingan semakin tinggi HGI makin mudah untuk digiling 59 Enterprise based Vocational Education

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Ada pertanyaan ?....

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