Transcript EP FOR J PLANT UPGRADE

J ACID PLANT CAPACITY
INCREASE
PRESENTER:
SIYABONGA MALEVU
COMPANY:
CHEMICAL INITIATIVES
DEPARTMENT:
TECHNICAL
J PLANT BACKGROUND
J PLANT BACKGROUND
FULL RATES PRIOR TO CAPACITY INCREASE

Production rate:
500 tons/day of H2SO4

Air flow rate:
45 000m3/hr

Sulphur rate:
7 tons/hr

Burner SO2 conc.:
10.5% (burner temp of 1000 oC)

Catalyst loading:
LP12O for 1st and 2nd pass & LP110 for 3rd & 4th
pass

Converter overall conv.:
99.5%

SO2 emission:
350 – 500ppm
PRE-PROJECT SIMULATION
DATA

Production rate:
547tons/day of H2SO4

Air Flow rate:
47 500m3/hr

Sulphur rate:
7.4 tons/hr

Burner SO2 conc.:
11% (Burner temp: 1025 oC)

Catalyst loading:
LP120:1st&2nd Pass, LP110:3rd pass&VK69: 4th Pass

Overall converter conv.:
99.79%

SO2 emission:
100 – 350ppm
CONVERTER MODIFICATION

3rd pass catalyst loading increased by 18.6% (from 20 350
to 25 000 litres).

The extra 4 650 litres obtained from 4th pass.

4th pass LP110 catalyst replaced with VK69 catalyst.


4th pass catalyst loading increased by 26.7 % (from 22
000litres to 30 000litres).
3rd and 4th pass thermocouples re-allocated to
accommodate the increased catalyst bed depths.
VK 69 BENEFITS

High surface area ------ high activity

High void fraction ------ low pressure drop

Reduced SO2 emissions

Increased production with low SO2 emission levels

Long lifetime
EVALUATION OF CAPACITY OF MAJOR EQUIPMENT
Critical investigated areas were:
•
AIR BLOWER CAPACITY
Prior – running at 43 000m3/h at discharge pressure 42 kPa
Design max capacity – 47 500 m3/h at 47 kPa discharge pressure
Blower curves – 47 500 m3/h at 46.5 kPa discharge pressure
Possible by increasing blower vanes angle to maximum
Increase power consumption by 4 kW.
•
SULPHUR BURNER CAPACITY
Sulphur consumption – increase from 6.8 ton/h to 7.4 ton/h
Consultation with original designers – burner large enough to
increase acid plant by 20%.
•
CONVERTER CAPACITY
3RD Pass maximum catalyst volume: 25 100 litres
4th Pass maximum catalyst volume: 30 300 litres
Increase 4th pass pressure drop from 0.5 kPa to 0.79 kPa.
•
COOLING CAPACITY
Burner temperature increased to 1025 0C.
1st Pass Converter temperature decrease from 433 to 430 0C
WHB #1 – enough capacity for additional 1.8 ton/h steam generation
EVALUATION OF CAPACITY OF MAJOR EQUIPMENT
Drying, Interpass, Final Absorption Towers
 Sulphur pump, BFW pump, Acid pumps
 Hot and cold heat exchangers
 Main Benefits:

– Additional 47 ton/day acid production
– Additional 43.2 ton/ day steam generation
Payback period: 6 months
ECONOMIC EVALUATION
 Main
Benefits:
– Additional 47 ton/day acid production
– Additional 43.2 ton/ day steam
generation
Payback period: 6 months
450
Time (months)
Nov-08
Oct-08
Sep-08
Aug-08
Jul-08
Jun-08
May-08
Apr-08
Mar-08
Feb-08
Jan-08
Dec-07
Nov-07
Oct-07
Sep-07
Aug-07
H2 SO4 (tpd)
Production trends (Aug 07-Dec 08)
570
550
530
510
490
470

Prior to implementation: 477 tpd

Target
: 547 tpd

After implementation
: 533 tpd
Failure of maintaining the 4th pass inlet
temperature below 405 0C without
compromising the desired export steam
temperature at the boiler station
SO2 emissions
50.00
Actual emissions (tons)
45.00
40.00
35.00
30.00
Ser i es1
25.00
Li near (Ser i es1)
20.00
15.00
10.00
5.00
0.00
Jan-07
Feb-07 M ar -07 Apr -07 M ay-07 Jun-07
Jul -07 Aug-07
Sep-07 Oct-07 Nov-07 Dec-07 Jan-08
Feb-08 M ar -08 Apr -08 M ay-08 Jun-08
Jul -08 Aug-08
Sep-08 Oct-08 Nov-08 Dec-08
ACID PLANT 20% UPRATE
PHASE II
550 to 600 MTPD
EXPORT STEAM
TEMPERATURE
OPERATE THE
BOILER AT MAX
PRESSURE
REDUCING HEAT
LOSSES @
EXPORT LINE
GENERATE
ELECTRICITY
FROM STEAM
AIR BLOWER
CAPACITY
MAIN COOLING
TOWER CAPACITY
PLANT PRESSURE
DROP
REDUCE
CONVERTER
PRESSURE DROP
REDUCE IAT &
FAT PRESSURE
DROP