SFR-based mobile system for heat recovery

Robert Aranowski, Aleksandra Korkosz, Konrad Smolarczyk, Joanna Mioduska, Jan Hupka

Department of Process Engineering and Chemical Technology

UBIS International Energy Conference

Vilnius, 8-10th October 2019

Incentive for the pilot

Industrial symbiosis is an important element of the circular

economy as it offers tools to make better use of existing

resources.

The industrial symbiosis - as understood at GUT - is mainly of

economic importance, nevertheless, the undoubted

environmental benefits also speak for its implementation.

Symbiosis contributes to local development and the increase

of corporate social responsibility, as well as mitigates climate

change.

Pilot installation using SFR reactorOur task in the UBIS project was, design and

construction of an installation for low-

temperature heat recovery from exhaust gases

of diesel engines.

The installation uses a new, very efficient gas-

liquid heat exchange system in the Spinning

Fluids Reactor SFR.

This heat can be used in another enterprise or in

a public facility, e.g. greenhouses and for heating

the sidewalk in the vicinity of public

transportation stops in winter.

Direct contact heat exchangers

Involve heat transfer between

hot and cold streams of two

phases in the absence of a

separating wall.

Can be classified as:

▪ Gas–liquid

▪ Immiscible liquid–liquid

▪ Solid-liquid or solid–gas

Most direct contact heat

exchangers fall under the

Gas–Liquid category.

Direct contactors for heat recovery

Disadvantages▪ The fluid streams mix, unless the streams are immiscible▪ Comparable pressure of contacting phases▪ Evaporation of the liquid, contamination of the gas phase

Advantages

▪ Lack of surfaces to corrode or foul▪ Compact size of heat exchanger per energy flux▪ Significantly extended heat transfer surface area▪ Heat transfer at much lower temperature difference between the two streams▪ Low pressure drop▪ Low capital and operating costs▪ Removal of fine particles (soot)▪ Selective removal of gaseous contaminants

Direct Contact Heat Exchangers

▪ Spray columns

▪ Baffle tray columns

▪ Sieve tray or bubble tray columns

▪ Packed columns

▪ Pipeline contactors

▪ Mechanically agitatedcontactors

▪ Spinning Fluids Reactor (SFR)

Typical mechanically

agitated towers

[Treybal, (1966)].

Schematic of a disk and donut baffle tray

column for use as a steam condenser

[Jacobs and Nadig (1987)].

Design and principle of SFR operation

▪ New efficient liquid-gas contacting system for energy recovery is offered

▪ The operating temperature for the gas phaseis up to 600C

▪ Low pressure drop for the gas phase

▪ Possibility of SFR scale-up by multiplication of units

Reactor Head

Reactor Body

Inner Porous Partition

LIQUID INLET

GAS INLET

Liquid flow in SFR Top view of the SFR interior

Bubble generation mechanism in stagnant liquid

wFF

= gNd

r ggc

p

k −= )(6

2

3

3

)(12

gN

rd

ggc

kp

−

=

Bubble generation

in stagnant liquid

Where:

rk - radius of capillary,

- surface tension,

dp - diameter of bubble,

c - density of liquid,

g - density of gas,

g - gravitational acceleration,

Ng - dimensionless centripetal acceleration

ow FFF

+=42

22

bc

o

duF

=

2

16

u

rd

c

k

b

=

4

1

32

24

=

c

kp

f

r

ud

Bubble generation in flow liquid

Where:

db, dp - diameter of bubble,

u - linear liquid velocity,

- resistance coefficient depended

from Reynolds's number,

- viscosity,

f - friction factor

Laminar flow Turbulent flow

Bubble generation mechanism in stagnant liquid

SFR inner porous tube

Gas bubbles generated in SFR

50 L

/min

Water 5 ppm MIBC

30 L

/min

70 L

/min

Wa

ter

flo

wra

te

Materials for inner porous tube or screen

∆P𝑝= ∆𝑃𝑑 + ∆𝑃𝑐

Where:

∆P𝑝 - gas phase pressure drop,

∆P𝑑 - resistance of flow through

the porous material

∆P𝑐 - resistance of gas flow

through the layer of

rotating liquid

Bubble size distribution for QW =

20 dm3/min, QG= 55 m3/h

Ab

un

dan

ce(%

)

Diameter (mm)

Bubble size distribution in SFR

Bubble size distribution for QW =

20 dm3/min, QG= 25 m3/h

Ab

un

dan

ce(%

)

Diameter (mm)Bubble size distribution for QW =

20 dm3/min, QG= 35 m3/h

Ab

un

dan

ce(%

)

Diameter (mm)

Bubble size distribution for QW =

30 dm3/min, QG= 45 m3/h

Ab

un

dan

ce(%

)

Diameter (mm)

Residence time of liquid in SFR

Porous Partition -Perforated Plate

0 20 40 60 80 100 120

0,2

0,4

0,6

0,8

1,0

Re

sid

en

ce

Tim

e (

s)

Gas flow (m3/h)

Liquid flow (dm3/min)

37.5

56.3

75.0

0 20 40 60 80 100 120

0

5000

10000

15000

20000

25000

Inte

rfe

cia

l a

rea

(m

2/m

3)

Gas flow (m3/h)

Liquid flow (dm3/min)

18.7

37.5

56.3

75.0

Packed columns vs. SFR system

7 m

0,7 m

0,40 m

0,24 m

Typical interfacial area in absorption column is 60-440 m2/m3

Interfacial area in SFR system is up to 20 000 m2/m3

Ajay Mandal, Gautam Kundu* and Dibyendu Mukherjee, Interfacial Area and Liquid-Side Volumetric Mass Transfer Coefficient in a Downflow Bubble

Column, The Canadian Journal of Chemical Engineering, Volume 81, April 2003, 215-219

Flow sheet of the pilot installation

Main components

1. Spinning Fluids Reactor

2. Liquid phase Reservoir

3. Liquid-liquid heat exchanger

4. Blower

5. Recirculation pump

6. Coalescer

V-2.0 V-2.1 V-2.2

55

PT FT

DN100/80

DN

80/1

5V

-3.3

5D

N15

/6

A

DN

6/15

V-3.44

GAS

ANALISER

EXHAUST

GASES

DN25COLD

WATERV-1.1

DN25DN25

FT

DN25

TT

DN25

HOT

WATER

DN25

V-1.2DN25DN25

FT TT

DN25

DN25

E-1.0

DN25

DN25

DN25

DN25

DN25

V-1

.0

DN25

V-1

DN25

SFR

E-1.0

DN

100/DN

80

DN

100/DN

80

P-1

DN50DN50

DN100/80

COLD

GASESDN25

DN25

DN15

COLD

GASES

FT

DN25

V-1.2

DN25DN25

55

PT

TT

DN25

DN25

V-2

.1

V-1.1 DN25

4

2

1

3

5

6

Design of the installation

Main components1. Spinning Fluids

Reactor

2.Liquid phase reservoir

3.Liquid-liquid heat exchanger

4.Blower

5.Recirculation pump

6.Coalescer

7.Electrical switchgear

1

2

3

4

6

5

7

1

6

2

1

2

6

Control system for the pilot installation

0 1000 2000

5

10

15

20

25

Tem

pera

ture

[oC

]

Time (s)

Liquid inlet

Liquid outlet

0 500 1000 1500 2000 2500

0

20

40

60

80

100

120

140

160

180

Tem

pera

ture

[oC

]

Time (s)

Gas inlet

Gas outlet

• Determining optimal ratio of gas and liquid flow

• Analysis of exhaust gases purification

• Determining the degree of fine particles removal

• Selection of liquid phase in terms of volatility, dust collection and removal of selected components from exhaust gases

Low temperature heat recovery tests

Temperature profile during tests

Thermal analysis of heat recovery

The amount of heat transferred through the area dA can be calculated from below equation:

where Th and Tc are the local temperatures of the hot and cold fluids. α is the local heat transfer coefficient and dA is the local incremental area on which α is based.

The overall heat transfer coefficient U is given by equation:

For constant temperatures and heat transfer coefficients below equation can be used:

𝑑 ሶ𝑄 = 𝑈 𝑇ℎ − 𝑇𝑐 dA

1

𝑈=

1

𝛼ℎ+

1

𝛼𝑐

ሶ𝑄 = 𝑈 𝑇ℎ − 𝑇𝑐 A

The thermal analysis of heat recovery

The amount of heat transferred in SFR can be calculated from equation:

The enthalpy if streams can be calculated from

If we assume: ሶ𝑄𝑙 = 0

If we know A we can calculate U

Other assumption: P=const. W=0

𝐻𝑔ℎ 𝐻𝑔𝑐

𝐻𝑐ℎ

𝐻𝑐𝑐

ሶ𝑄𝑙

ሶ𝑄 = 𝐻𝑔ℎ −𝐻𝑔𝑐 = 𝐻𝑐ℎ −𝐻𝑐𝑐 + ሶ𝑄𝑙

𝐻𝑖𝑇 = 𝐻𝑖

0 + න

𝑇0

𝑇

𝑓(𝑐𝑝)𝑑𝑇

𝐻𝑔ℎ −𝐻𝑔𝑐 = 𝐻𝑐ℎ −𝐻𝑐𝑐 = 𝑈 𝑇ℎ − 𝑇𝑐 A

Simulations/calculations of low temperatureheat recovery using SFR

19.405 kW

1.273 kW

HE

AT R

EC

OV

ER

Y

18.603 kW

2.075 kW

Electrical power

Exhaust gases

Energy lost - 1,1%

Heat recovery 98,9%

Assumptions:

▪ Exhaust gas temperature 500°C

▪ Gas phase flow rate 60 Nm3/h

▪ Temperature of hot and cold liquid phase, respectively 85 and 40°C

Design of four-unit SFR module

Cross-section of multi-SFR

heat recovery system

Top view of SFR head arrangement

in heat recovery module

Principle of generation

of absorbent swirl flow

Final Comments

Study visits and workshops will be organized at several

companies in Pomerania, during which the prototype

installation for heat recovery will be demonstrated.

Nevertheless, extra funds are needed.

The ability to directly familiarize participants with the

functioning of the installation and asking questions will

allow to verify thoughts, mutually inspire and exchange

ideas.

Thus new cases of industrial symbiosis can be identified.

Thank you for yuour kind attention