IP Steam Research Articles

Heat Integration of KIERDRY Process with a Power Plant Using gPROMS

In this study, thermal efficiency of power plant has been evaluated by integrating the KIER-developed dry-sorbent CO2 capture process (KIERDRY) with a pulverized coal-fired power plant using a commercial simulator, gPROMS. A simple basic KIERDRY model has been developed and connected it to PCPP (Pulverized Coal Power Plant) example in gCCS, a system modelling tool for support of design and operating decisions across the CCS chain. The PCPP capacity of 500 MWe and the KIERDRY capacity of 150 MW (125 tonCO2/hr based on captured amount) have been set as a base case. We consider HP steam(307 oC, 31bar) and IP steam(461 oC, 14∼14.6bar) as the utility steam of a regenerator in KIERDRY since the steam condition of a regenerator has been set to approximately 14.6∼15bar, saturated. Totally 5 cases have been evaluated: (1-1) Use HP steam, use condensate to make a process steam, and return to condensate(1bar); (1-2) Use HP steam and return to 5th feed water heater(12bar); (2-1) Use IP steam, use condensate to make a process steam, and return to condensate(1bar); (2-2) Use IP steam and return to 5th feed water heater(12bar); (2-3) Use IP steam, do additional heat integration by preheating dry sorbents at loop-seal, and return to 5th feed water heater(12bar). As a result, the condensate generated at the regenerator should be returned to the power plant rather than used to make a process steam, which is supplied as a reactant for the carbonation reaction. Based on several case studies, the reduction of the power output of the PCPP with KIERDRY has been varied from 29.2 MWe(minimum penalty) to 71.7 MWe(maximum penalty). Thus, it can be concluded that the energy penalty of KIERDRY has been significantly reduced by how heat has been integrated with PCPP.

Spotlight on the IPS Team of the Year 2015

Spotlight on the IPS Team of the Year 2015

Summary of Dialogues at IPS

This segment contains, in a summarized form, the deliberations of some of the events and discussions at IPS during the second half of 2014. The write-up has been prepared by IPS Azeem Khalid, an IPS team member, also utilizing the post-event briefs prepared by coordinators.

ICOPE-15-C052 The reduction of stator blades losses by chord spanwise parabolic variation in an IP steam turbine

Under the condition of settled stator blade vortex design, the blade chord variation along spanwise direction can significantly change the endwall losses, and possibly the profile loss in the mid-height section. One way to reduce these losses is by decreasing the relative pitch-chord ratio at the root and tip height region, and increasing it or keeping it the same from the original one at the mid-height region. This paper presents a CFD study where two different stator blade chord spanwise variation methods are applied to the stages of an IP steam turbine. The original one is of the traditional method where the stator blade chord remains constantly or increases linearly along blade height. While the new one has the characteristics as follows: the stagger angle and scale of the 2D profile geometry are changed compared with the original one; the variation of blade chord throughout the height of the blade is parabolic, with large chord in the endwall region, and small chord in the mid-height region; the 2D profile stagger angle on different section heights is changed from the original one to maintain the same blade vortex design; the blade number is slightly changed to satisfy the pitch-chord ratio requirements while keeping the section moduli and moments of inertia almost the same. The CFD calculation results show that, with the new design strategy, the stator endwall loss decreased significantly, and the profile loss in the mid-height section reduced slightly as well, compared with the original one.

Quest for Peace: Dealing with Militancy

Considering the wide-ranging dynamics of militancy the country is faced with, dialogue and negotiated settlement — keeping in view the larger regional security context as well as long term structural aspects — provides the ideal way forward. Deterrence indeed is necessary to maintain and may be resorted to, where and when it is inevitable; keeping however in view that force can hardly provide a permanent solution to such multidimensional and long standing problem. While moving for dialogue devising a proper, well-though-out mechanism, with a logical end in view should be ensured. The role of traditional institution of jirga, and community elders is instrumental in this regard and must be pursued. International experiences stand testimony to the need for consistency and secrecy in such endeavors. And last but not the least, the people of militancy hit areas will have to be given a clear message that their developmental needs will be met, properly. The write-up is based primarily on deliberations of IPS roundtable “Negotiating Peace: Dealing with the Taliban — Current Status and Options” held on November 12, 2013. Following the Chatham House rules, the comments of the panelists and participants are being given unattributed. Important documents, national and international, related to the subject are also annexed. Editors are thankful to Ms. Fehmeedah Khalid, an IPS team member, for assistance provided in preparation of this write-up.

Thermodynamic model of HP–IP leakage and IP turbine efficiency

Abstract In this paper, temperature variation method and numerical calculation method are both presented for the calculation of the HP–IP steam leakage through midspan packing (N2 packing), which is called N2 leakage for short, and an error analysis mathematical model about the impact of measured parameters error on N2 leakage rate is established. The two methods have been both applied to a 600 MW supercritical steam turbine’s N2 leakage rate estimation, and the results show that numerical calculation method can estimate N2 leakage rate as accurately as temperature variation method, and the chief parameters which affect the accuracy of N2 leakage rate are hot reheat temperature and IP turbine exhaust temperature. Taking the leakage from HP turbine exhaust balance piston to IP turbine exhaust zone (N1 leakage) quantity into account, which has great influence on N2 leakage calculation precision, combined with N2 leakage, IP turbine efficiency is calculated exactly, and the result indicates that: Compared to N1 leakage, N2 leakage is the main factor which affects the IP efficiency.