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turning theKey on Intergraph's Plant Design

IP.com Disclosure Number: IPCOM000218727D
Publication Date: 2012-Jun-06

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VERTICAL SPLIT-FLOW BASKET MODIFICATION

THE M. W. KELLOGG COMPANY

HOUSTON, TEXAS

PRESENTED AT

GULF COAST AHHONIA PRODUCERS MEETING

BATON ROUGE, LOUISIANA

APRIL 1986


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VERTICAL SPLIT-FLOW BASKET MODIFICATION

INTRODUCTION

Retrofitting a Kellogg Ammonia plant to provide significant in- creased capacity and/or reduced energy consumption generally includes upgrading the performance of the converter system. To accomplish this, Kellogg has pre~iously offered two general re- trofit options. The converter system could be upgraded either by

I) paralleling the existing quench converter or by 2) replacing
the converter with a low-energy, intercooled converter. Although
the economics are favorable for each of these options the~in- y. /

stalled cost of either a new or used converter "

~- ~'T"F'~v~'~

With the current state of the market, there is a need for a low cost converter retrofit option capable of providing the enhanced performance necessary for a short pay-out. With the vertical split-flow basket modification, Kellogg has addressed this need.

The vertical spilt-flow basket modification consists of a modifi- cation to the existing converter which changes the configuration from a direct quench design to that of a low-energy, intercooled design. The result is a substantial increase in conversion per pass as well as a reduction in converter pressure drop.


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The improved performance results in significant advantages in synthesis loop operation:

Reduced synthesis gas compressor horsepower Reduced refrigerant compressor horsepower

Potential for increased ammonia production

VERTICAL SPLIT-FLOW CONFIGURATION

The basic configuration of the modified converter actually dates back to 1983. In that year, Kellogg filed a patent application (issued 1984)~fo~a vertical two-bed intercooled converter in which the second bed was split into two-beds operating in para- llel. This "split-flow" configuration provides a substantial reduction in pressure drop which allows the use of small, high activity catalyst (1.5-3mm). In addition, the intercooled con- figuration provides not only increased efficiency compared with direct quench temperature control, but also the potential for a high converter effluent
steam generation. The

temperature suitable for high pressur~ process design and performance is in

effect identical to that of the horizontal intercooled converteri~,~ p~

" low energyAp±an~s. ~!!t._.e~-~.~ ~~

The configuration and flow pattern converter are illustrated in Figure I. Like the converter utilizes a cold wall pressure of the vertical spilt-flow it~ predecessors,

shell with an/@


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/~ternal basket housing the exchangers and catalyst beds. The lntercooler provides cooling of the bed 1 effluent gas by heat
exchange with converter feed gas. The feed/effluent exchanger allows the low inlet temperature of the original quench converter to be maintained while cooling the converter effluent gas to a temperature compatible with...