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Industry 4.0

Mondi Stambolijski sets new standards

with

Virtual Digester House

Ninth National Conference on Chemistry - Sofia 9. 2016

www.automationX.comwww.procsim.eu

Batch Cooking Process

1


Wood cooking is well proved technology, is

robust, but after charging of cooking chemicals

it proceeds in blind flying till the end.

Except time and temperature there is hardly

any other process information available.

Therefore the starting conditions must be

known as precise as possible

2


Basic starting conditions:

- wood weight in digester (tons)- belt scale- position of feeding belt

- chip distribution on belt during chip filling

- weather (rain, frost, ice)

- chip moisture (%)- laboratory representative sampling (time for result)

- online measurement (weather)

- strength of cooking chemicals (g/l)- representative sampling (sampling place)

- robust of laboratory procedures

3


Data analyze: wood weight in digester (tons)

4

Digester 1 2 3 4 5 6

Weight (tons) 39,24 41,61 39,30 39,68 40,06 39,78


Data analyze: wood moisture calculation (%)

5

Simple moisture calculation from

chip volume and chip weight does

not match with sporadic laboratory

values (cal -> 15%, lab -> 7%)

Calculation using hydro module

with heating steam match with

laboratory values and can even

substitute expensive measurement


Fast changes of heating steam flow is a serious

problem in turbine house!

6

Long response time makes serious difficulties of steam flow control


Fast changes of heating steam flow is a serious

problem in turbine house!

Old heating sequence was controlled by means of

temperature curve, which does not support required

smooth changes of steam flow.

New algorithm controls digester heating by means of

digester specific heat derived during the first heating

minutes. This algorithm calculates how much steam will

be needed for digester heating, which enables full control

of steam flow.

7


Heating steam flow solution:old temperature control new steam flow control

8

Δ 10,4 t/h in 9 min = 1,15 t/h/min

Serious difficulties for control of

steam network pressure

Gradient of steam flow change before and afterΔ 8 t/h in 18 min = 0,44 t/h/min

below demanding limit 0,5 t/h/min

9 min 18 min


To improve process control efficiency

additional process information is a must

Measurement instrumentation is expensive- Purchase

- Installation

- Maintenance

Digitalization of technological processes

multiplies information flow

9


Digitalization is mathematical algorithm of physical

functions and chemical reactions including technical and

technological parameters of real equipment.

The precision of such simulation is close to accuracy on

installed instrumentation. The interface to the virtual

equipment is similar to the real one

10

Program Start


Production control of Batch Digester House in

connection of downstream continual paper machine

Production plan for the next 24 hours of cooking (red bars) is

calculated according to the evaluation of stored pulp before PM

(blue line) and PM production plan (yellow line). It ensures

enough space for pulp from the digester in the case of the break

and enough pulp for PM in the case of sequence disturbance in

the digester house. Program Start


Operator Interface to Mill coordination program

The targeted use of pulp inventories in the major

vessels reduces the inefficient time in Digester House

to a minimum and thus maximizes production

capacity of the paper machine!


• A completely new feature in paper industry is the prediction of

the steam consumption from Digester House for the next 60

minutes.

• The virtual Digester House is regularly synchronized with the

real one and simulates the process flow trajectories one hour

ahead.

• This online predictive function is unique in the pulp industry

and supports secure control of the steam production and

increases the efficiency of the steam turbine.

Virtual Digester House predicts steam consumption!


Communication with existing control system


Project results:

15

- Due to the new digester heating steam flow control, the

fluctuation in steam consumption has been reduced by 30%

- The predetermined turbine house maximum change in the

steam consumption in one minute was even reduced by 20%.

- The fluctuation of the kappa number was reduced by 15% which

brings in the range of lower Kappa (in the rules) an exploitation

of up to 1.4% more pulp

- The forecasted information on steam consumption in the next

60 minutes has greatly enhanced the stabilization in the steam

network.

www.automationX.comwww.procsim.eu16

Simulation of technological

processes is the most

efficient way to the success

Thank you for your patience

industry 4 - welcome at cf procsim gmbh | procsim.eu

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