The Spent Catalysts Generated Globally Analysis Assignment Sample

Subject Name : Management

Current Practices for End of Life Management

Table of Contents

Introduction.

Material Flow Analysis.

References

Introduction to The Spent Catalysts Generated Globally Analysis

Catalysts play an instrumental role in oil refining industry. There are various kinds of catalysts , however, the main types of catalysts are reforming catalysts, fluid catalytic cracking catalysts and hydroprocessing catalysts. The impurities that contaminate catalyst during processing are nickel, vanadium, sulfur and coke (these components are present in crude oil feed). As a result, a catalyst deactivates with passage of time (Kim and Kim, 2018).

A life cycle of Diesel hydrodesulfurization catalysts have 3-4 years, however, FCC catalysts looses daily and they can be changed monthly depending on their activity. The catalyst is withdrawn from the process after completion of their life cycle. They are known as spent catalysts, spent catalyst is poisonous as it contains coke and heavy metals).

The total amount of spent hydroprocessing catalyst produce worldwide is 150,000-170,000 tons/year according to Dufresne estimation (Chiranjeevi et al., 2016). A projected annual increase in catalyst consumption is 5% (Chiranjeevi et al., 2016). An evaluation of projected spent catalysts generated globally and in Australia over the next 20 years is calculated in table 2

Table 1: amount of spent catalyst and projected annual increase (Chiranjeevi et al., 2016)

Amount of spent hydroprocessing catalyst produce worldwide (tons/year)	150,000-170,000
Projected annual increase	5%

Table 2: An evaluation of projected spent catalysts generated globally and in Australia over the next 20 years

Year	Spent catalysts generated globally and in Australia over the next 20 years (tons/year)
1	160,000
2	168000
3	176,400
4	185,220
5	194,481
6	204,205
7	214,415
8	225,136
9	236,393
10	248,213
11	260,623
12	273,654
13	287,337
14	301,704
15	316,789
16	332,629
17	349,260
18	366,723
19	385,059
20	404,312

Therefore, the projected amount of spent catalyst that can product globally over the next 20 years is 404,312 tons/year.

Landfill is the traditional way for deposition of spent catalyst, however, it is not an environmental friendly method as this method causes contamination of ground water. To minimize generation of hazardous wastes, (Malekian, Salehi and Biria, 2019), the amount of spent hydroprocessing catalyst could be minimized if the life of catalyst prior to disposal can be extended for longer period of time. It can be done in the following ways

Regeneration or reuse

Catalysts deactivates with deposition of coke. To regenerate it, combustion is used to remove deposited coke). Catalyst activity recovers after repetitive combustion until desired activity is achieved. The temperature and oxygen concentration should be carefully controlled during coke burning.

Usage in hydrotreating processes that require less demanding. For example, spent NiMo/Al₂O₃ and CoMo/Al₂O₃ catalysts from gas oil units can be used as adsorbents for sulfur, aromatic compounds and hydrogen removal from hydrocarbon feedstock.
Minimization of catalyst consumption by using improved catalysts that are more stable and have longer life.

Material Flow Analysis

A material flow analysis of fluid catalytic cracking unit is performed in attached excel sheet. A modern FCC consists of these three major units as shown in figure 1

Riser reactor
Stripper, Regenerator
Fractionator
Slurry settler

The correlations given in table 3 are used to find product quantities in Fluid Catalytic Cracking unit (Abdalla, Elnour and Fayez Syed, 2016)

Table 3: Correlations to find quantity of products in Fluid Catalytic Cracking Units

Coke (wt%)	0.0536 ×conv-0.18598×API+5.966975
LCO (light cycle oil) (LV%)	0.0047×conv²-0.8564×conv+53.576
Gases (wt%)	0.0552 ×conv+0.597
Gasoline (LV%)	0.7754×conv-0.7778
iC₄ (LV%)	0.0007 ×conv²+0.0047×conv+1.40524
nC₄ (LV%)	0.0002 ×conv²+0.019×conv+0.0476
C₄ olefin (LV%)	0.0993 ×conv-0.1566
C₃ (LV%)	0.0436 ×conv-0.8714
C₃ olefin (LV%)	0.0003 ×conv²+0.0633×conv+0.0143
HCO (heavy cycle oil)	100-conv-(LCO LV%)
Wt % of S in Gases	3.9678×(Wt% of S in feed)×+0.2238
Wt% of S in LCO	1.04994×(Wt% of S in feed)×+0.00013
Wt% of S in HCO	1.88525×(Wt% of S in feed)×+0.0135
S in coke (wt%)	Wt% of S in feed-wt% of S in gases-wt% of S in LCO-wt% of S in HCO
Gasoline API	-0.19028×conv+0.02772×gasoline LV%+64.08
LCO API	-0.34661×conv+1.725715×feed API

Source: (Abdalla, Elnour and Fayez Syed, 2016)

References for The Spent Catalysts Generated Globally Analysis

Abdalla, A., Elnour, H. and Fayez Syed, K., 2016. MODELING AND DESIGN OF FLUIDIZED CATALYTIC CRACKING RISER. Graduation. Sudan University of Science & Technology.

Chiranjeevi, T., Pragya, R., Gupta, S., Gokak, D. and Bhargava, S., 2016. Minimization of Waste Spent Catalyst in Refineries. Procedia Environmental Sciences, 35, pp.610-617.

Kim, S. and Kim, S., 2018. Void Properties in Dense Bed of Cold-Flow Fluid Catalytic Cracking Regenerator. Processes, 6(7), p.80.

Malekian, H., Salehi, M. and Biria, D., 2019. Investigation of platinum recovery from a spent refinery catalyst with a hybrid of oxalic acid produced by Aspergillus niger and mineral acids. Waste Management, 85, pp.264-271.

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