Assessment report (Digested)on

The Kemco Witmanby

A Calcium Carbonate Producerwho uses the Kemco Witman (2 units)

in Japan

“Kemco Witman” Centrifugal Powered Screw Ejecting Dryer 1

Part 2 : Customer report

1) Background: Problem Solution:

2

A) Post primary crushing: In order to produce a quality product, Calcium Carbonate is washed & dried before being

transferred to grinding and de-dusting processes.

B) Products: Moisture Drying process Application By Kiln Dryer

10mm-3mm 6% down to less than 1% Calcium carbonate 3mm-0mm 15% down to less than 1% Calcium carbonate

The moisture content to be fed to grinding and de-dusting processes shall be less than 1%.

Problems and solution for drying: The problems by Kiln dryer: Solution by Witman (see page 6 for details)

1) Initial investment is high. 1) Saved by 70% 2) CO2 emission is high. 2) Saved by more than 50% 3) Energy cost is high. 3) Saved by 62% to 76% (62% for 10-3mm and 76% for –3mm)

4) Silt in the feed can be adhered 4) N/A to the inner wall of Kiln dryer. 5) Large space requirement. 5) L 1.5m x W1.4m x H1.1m Kiln dryer: 9m length and 1.5m diameter

6) Operator is required 6) Un-manned operation

2) The performance at the actual production line:

3

A) Feed size 　 10-3mm 3-0mm

B) Moisture 1) Feed Moisture content 6% 15% 2) Products <Target> <less than 1%> By spin only 0.77% 1.2% By spin and heat 0.5% 0.85%

C) Production volume 5 t/h 5 t/h

D) Wash effect by “Working water”. E) Size distribution of the feed and products. Silt contained in the feed is removed by There is no change of size distribution between “Working water” as shown in the picture feed and product. However, individual cases are below. subject to test results at the Kemco test plant.

Production yield is 93%.

Before After

Feed

Products

Fine particle dust water

Sieve mesh size

Lime stone, 3-0mm, 5t/h

3) - a) The best drying analysis for the Witman heater:<data collection>

4

Drying efficiency analysis of the Kemco Witman heater is procured by thermal calculation using the temperatures measured at 5 detecting points (Q1 to Q5).

Key:

Q1 : The calorie to be evaporated.Q2 : The calorie to be used for heating the feed.Q3 : Heat loss from the body of WitmanQ4 : Calorie in the exhaust air.Q5 : Calorie in the dust water.

Water Material

Water

Heat

5

Q1 :The calorie to be evaporated

Q2: The calorie to be used for heating the feed

Q3: Heat loss from the body of Witman

Q4: Calorie in the exhaust air

Q5: Calorie in the dust water

Heat temperature: 110o

C Heated air volume 41m

3/m

68.5% of all the given calories are used for evaporation.

In the case of feed being 3-0mm, the heater shall be used for obtaining the targetedmoisture content, say less than 1% (as shown In page 3). The above is the result which was obtained through thermal calculations by using the temperatures from fivedetecting points (Q1 to Q5) when the products are in the best drying condition.

3) - b) The best drying analysis for the Witman heater: <data collection>

4) Comparison between Kiln dryer and The Kemco Witman:　

6

BeforeKiln

A) Drying process1 Qty 1 unt 2 units 2 units2 Peripheral device to be used Air blower and bag house3 Power required (kW) 11 15 x 2 units 15 x 2 units4 Heating device Barner (by heavy oil) Heater (30kW) x 2 units Heater (30kW) x 2 units5 Required energy for 1 ton products Heavy oil 7.7L/ t 6kW/ t 6kW/ t6 Mositure content in the products 0% 0.50% 0.85%

7 Required process before dry

Feed should be washed and cut by - 3mm, the process for which generates another - 3mm of surplus.

- 10mm can be fed without any additional process

- 3mm can be fed without any additional process

8 Required process after dry Dust is collected by gab house¥431/ t ¥71/ t ¥142/ t100% 16% 33%

B)Grinding and de- dusting process1 Crusher (Cage mill) (kW) 130 130 No need to be crushed2 Crushing capacity (t/ h) 10 10 Not applicable3 Production yield (%) 70% 70% Not applicable

¥153t/ h ¥153t/ h ¥0t/ h100% 100% 0%

¥584/ t ¥224/ t ¥142/ t100% 38% 24%

2)　Initial　invetment　cost　comparison 100% 30% 32%

A) CO2　emission 100% less　than50% less　than　50%

LaborOne watchman is required by fire department. N / A N / A

Remarks Power: \ 11.8/ kWh, Heavy oil: \ 56/ t

WitmanAfter

Cos

t an

alys

is

Environmentcost

Energy　cost　(\ / t)　- 　I

Energy　cost　(\ / t)　- II

C)　Total　energy　cost　(\ / t)　- I　+　II

Suction blower and drain pump

Sludge shall be pressed by filter press