Improving air quality is a key item on the

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Improving air quality is a key item on the Powered By Docstoc
					                   “As a result, an 18% increase of feed rate was achieved while maintaining the
      same cycle length under similar operating conditions.”




These results show that higher ppH2 not only improves                As a result, an 18% increase of feed rate was achieved while
performance and stability of the RDS catalyst, but is also           maintaining the same cycle length under similar operating
beneficial to product quality. This is especially the case with      conditions. As shown in Figure 6, Run-B exhibited even better
RFCC feed, since the RDS product is hydrogenated more under          stability than Run-A despite the higher feed rate.
high ppH2 with heavier molecules like asphaltene being cracked.
                                                                                                  176
As shown in Figure 4, hydrodenitrogenation (HDN) activity is




                                                                       HDS normalized WABT, oF
much improved by increasing the ppH2. Since nitrogen                                              140         Run A
compounds suppress the MAT conversion, low nitrogen content                                                   Run B
in the RFCC feed is very important to increase the gasoline yield.                                104

Commercial experience in high-pressure RDS unit                                                    68

A KFR-catalyst system was applied in a commercial high pressure                                     4
RDS unit, i.e. KFR 11/10/20/50 system, designated herein as
“Run-A”, being successfully operated for more than one year.                                     Base
                                                                                                        0      5       10       15          20   25    30
However, the refinery requested to further catalyst system
                                                                                                                             MOC, wt%
optimization so as to be able to increase the processing severity
using a higher feed rate. Therefore, KFR 22/33/53/70 system          Figure 6: HDS normalized WABT.
was proposed as “Run-B” instead.                                     In a subsequent article, we will discuss the development and
                                                                     unique capabilities of Albemarle's new KFR 23 catalyst,
The differences between catalyst systems “Run-A” and “Run-B”         designed for optimal performance in high ppH2 operation.
were:
                                                                     Contact: Jonnie Verwoert
I   KFR 11      KFR 22 – higher HDM activity and metal               Email:   jonnie.verwoert@albemarle.com
    capacity for high throughput operation
I   KFR 10, 20     KFR 33 – HDM/HDS catalyst with higher             Contact: Katsuhisa Fujita
    HDS activity                                                     Email:   katsuhisa_fujita@nippon-ketjen.co.jp

I   KFR 50     KFR 53, 70 – higher HDS activity on KFR 70
                                                                     Contact: Minoru Takada
    with higher metal tolerance than HDS catalyst KFR 53.
                                                                     Email:                             minoru_takada@nippon-ketjen.co.jp




Albemarle additives offer excellent
long-term option for SOx reduction

I mproving air quality is a key item on the agenda of many national governments and regulators. Both vehicular and
  direct industrial emissions of gaseous pollutants have become targets for more stringent regulation. In most
continents, these new regulations require refiners to reduce their sulfur oxides emissions.
In many cases, the FCC unit is the largest contributor to SOx        additives for SOx control. In this article, we study these options
emissions from the refinery so that SOx reductions from the FCC      and provide an economic comparison.
have become a key element in the refinery’s compliance strategy.
                                                                     Albemarle’s SOx reduction portfolio
Albemarle’s unique portfolio of SOx reduction additives offers
an excellent long-term option for meeting these new                  Albemarle entered the SOx market in the late 1980s with its
requirements. Albemarle’s patented technology forms the              patented hydrotalcite-based technology. Commercially, SOx
backbone of over 70% of all SOx reduction additives sold             reductions ranging from 25-99% have been reported, depending
worldwide. Many refiners are considering options for FCC SOx         on regenerator operation and unit specifics amount of additive
control and are beginning to compare the economics of using an       consumed and are being applied in many refineries worldwide.
investment option such as SOx scrubber against the use of

                                                                                                                                        Issue 70 I Courier 13
                 “Albemarle’s unique family of SOx reduction additives offer an excellent option for
   refiners seeking an effective and economically sound approach to emissions compliance.”




   KDSOx is recommended as the most cost-effective solution               Relative SOx reduction costs for both approaches are
   when a relatively small percentage (<5%) of additives is               illustrated in Figure 1.
   required to achieve the target SOx reduction. SOxDOWN is
                                                                                                   100
   now our most active additive for reducing SOx in FCC flue gas
   and is the highest activity peak-shaving additive.                                                                                              Flue gas scrubber




                                                                           Relative costs for sulfur
                                                                                                       80




                                                                            dioxide reduction, %
                                                                                                                                                   SOx additives

   Commercial experience has shown that in certain specific                                            60
   applications the performance of standard SOx reduction
   additives is not optimal. These applications include FCC                                            40
   operations running in deep partial burn or with very low
                                                                                                       20
   replacement rates. For these applications, Albemarle’s
   SOxMASTER provides more optimal performance compared to
                                                                                                        0
   traditional SOx reduction additives and has shown upto 90%                                               25%            50%               90%
   SOx reductions in deep partial burn applications, where                                                        Sulfur dioxide reduction
   typically at best 50–60% reductions have been reported.
                                                                          Figure 1: Relative sulfur dioxide reduction costs.
   Another advantage of SOxMASTER in particular is the
   significant reduction observed in condensible particulates             Even at a 90% reduction level, the additive option is a viable
   from the FCC unit stack.                                               one, and not only from a cost point of view. Proper additive
                                                                          application can help the refiner add value to the bottom line
   Economics of additives versus flue gas scrubber
                                                                          by allowing the processing of high-sulfur feed in the FCC.
   The two most widely applied options for SOx reduction in the
                                                                          Improved energy efficiency
   FCC are the use of additives – a non-capital solution – and
   installing a capital-intensive solution such as flue gas scrubber.     An additional advantage of the additives approach is its
                                                                          impact on overall energy efficiency. In addition to their
   To better understand their relative advantages, a case study was       concerns about reducing SOx emissions, refiners are also
   conducted comparing the economics of these two options.                seeking ways to reduce energy costs per barrel of crude
   Economics of the SOx scrubber option were taken from                   processed.
   “Controlling FCCU Regenerator Emissions” by K. Gilman, S.
   Eagleson and E. Weaver, WR 2000. Investment costs were                 Using Albemarle’s SOx reduction additive, which pick up
   corrected with a 4% annual increase. No adjustment was made            sulfur from the regenerator and release it as hydrogen sulfide
   for the operational costs associated with the flue gas scrubber,       in the reactor, has a minimal impact on the energy balance,
   which include costs for power, process chemicals and sludge            while installation of an energy-intensive flue gas scrubber is
   disposal.                                                              likely to have an adverse impact on the overall energy
                                                                          reduction program of the refinery.
   Specific cost per kg of sulfur dioxide removed were computed
   at 25, 50 and 90% reductions respectively, as shown in Table           An easy way to demonstrate the efficacy of these additives is to
   1. These costs were compared with the cost of achieving the            conduct additive trials, which can help the refiner quickly
   same objective using an additive option.                               establish the economics involved with employing additives for
                                                                          emissions compliance. In most cases this can be done quickly
       Sulfur dioxide            SOx additive       Flue gas scrubber     in a period of 4 to 8 weeks. As these comparisons have shown,
         reduction               specific cost         specific cost      Albemarle’s unique family of SOx reduction additives offer an
             %                $/kg sulfur dioxide   $/kg sulfur dioxide
                                                                          excellent option for refiners seeking an effective and
              25                       0.7                  4.1
                                                                          economically sound approach to emissions compliance.
              50                       0.9                  2.2
              90                       1.1                  1.4

   Table 1: Sulfur dioxide removal costs.
                                                                          Contact: Subramani Ramachandran
                                                                          Email:   subramani.ramachandran@albemarle.com




14 Courier I Issue 70