PROCESS ECONOMICS PROGRAM

Transcription

1 PROCESS ECONOMICS PROGRAM SRI INTERNATIONAL Abstract Menlo Park, California Process Economics Program Report No. 181 COGENERATION (April 1987) The revival of cogeneration in industrial plants is prompted by the high costs of energy and hastened by governmental incentives. Cogeneration can typically reduce fuel consumption by 25-35% in comparison with producing electricity and process steam in separate facilities. Among the governmental actlons in the United States, the Public Utilities Regulatory Policy Acts (PURPA) of 1978 has had the greatest impact on cogenerators. It removed many institutional barriers to industrial power producers and provided numerous guarantees which permit cogenerators to interact with public utilities on financially attractive terms. To illustrate the economics of cogeneration, we developed investment and operating costs for supplying electricity and process steam to a U.S. Gulf Coast plant producing 383 kt/yr caustic soda and kt/yr chlorine by the membrane process. The study considered three demand capacities for electricity and process steam: (a) capacity to meet only the requirements of the caustic/chlorine plant, (b) capacity to produce excess steam for export, and (c) capacity to produce both excess electricity and excess steam for export. Each of these demands is met by three different processes: Natural gas-fired combined cycle process (CC) Integrated coal gasification combined cycle process (IGCC) Petroleum coke-fired atmospheric fluid bed (AFB) boiler process. The estimated operating costs for the cogenerated electricity arel.9 to 3elkWh by the CC process, 7.9 to S.le/kWh by the IGCC process, and 0.41 to 2.2e/kWh by the AFB process. The current market price of electricity to large users supplied by the Houston Lighting & Power Company averages 46/kWh. Comparing ROls on the basis of discounted cash flows, the CC process is the most economically attractive: AFB ranks second. IGCC is uneconomical for industrial cogeneration because of its much higher investment and lower energy recovery from coal in comparison with the other two processes. PEP 85 JJLM SMK

2 Report No. 181 COGENERATION with contributions by JAMES J. L. MA by STEPHEN M. KOHAN a April 1987 I Cl I m A private report by the PROCESS ECONOMICS PROGRAM Menlo Park, California 94025

3 I I For detailed marketing data and information, the reader is referred to one of the SRI programs specializing in marketing research. The CHEMICAL ECONOMICS HANDBOOK Program covers most major chemicals and chemical products produced in the United States and the WORLD PETKOCHEMICALS Program covers major hydrocarbons and their derivatives on a worldwide basis. In addition, the SRI DIKECTOKY OF CHEMICAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States and Western Europe. ii

4 CONTENTS 1 INTRODUCTION SUMMARY......,... 3 General Aspects... 3 Economic Aspects... 4 Technical Aspects INDUSTRY STATUS...,...,..,...,...,..., PURPA Qualifications Avoided Costs Buy-and-Sell Agreement Financing Cogeneration Developments United States West Germany United Kingdom Japan COGENERATION TECHNOLOGIES....I..., 21 Thermal Efficiencies Cogeneration Cycles Comparison of Bottoming and Topping Cycles in Cogeneration Steam and Electricity Demand Patterns Turbine Operating Characteristics Steam Turbine Gas Turbine COGENERATION BY THE COMBINED CYCLE PROCESS... Utility Requirements for Caustic/Chlorine Plants... Study Cases and Design Parameters... Process Description... Process Discussion... Cost Estimates... Capital Costs... Operating Costs for the Packaged Boiler... Operating Costs for Combined Cycles... Cash Flows and Internal Rates of Return... Internal Rate of Return Sensitivities ul

5 CONTENTS 6 COGENERATION BY THE INTEGRATED COAL GASIFICATION COMBINED CYCLE PROCESS... Gasification... Review of Technology... Estimate Bases and Design Parameters... Process Description... Process Discussion... Cost Estimates... Capital Costs... Operating Costs for Coal Gasification... Operating Costs for Combined Cycles... Cash Flows and Internal Rates of Return... 7 COGENERATION BY PETROLEUM COKE-FIRED ATMOSPHERIC FLUIDIZED BED STEAM BOILERS... Review of Technology... Properties of Petroleum Coke... Availability of Petroleum Coke... Combustion of Petroleum Coke... Estimate Bases and Design Parameters... Process Description... Process Discussion... Cost Estimates... Capital Costs... Operating Costs... Cash Flows and Internal Rates of Return CITED REFERENCES iv

6 ILLUSTRATIONS Relative Energy Consumptions In Cogeneration... Cogeneration by Topping Cycles... Cogeneration by Combined Topping Cycle... Cogeneration by an Organic Fluid Bottoming Cycle... Steam and Electricity Demand Pattern In the Chemical Industry... Steam and Electricity Demand Pattern In the Petroleum Refining Industry... Conventional Power Generation... Cogeneration by Use of a Back Pressure Steam Turbine... Effect of Load Factor on Steam Turbine Efficiency... Thermodynamic Brayton Cycle for Gas Turbines... Effect of Process Variables on Gas Turbine Efficiency... Effect of Partial Loads and Ambient Temperature on Gas Turbine Heat Rate... Process Steam Generation by the Package Boiler Process--Base Case Flow Sheet... Cogeneration of Steam and Electricity by the Combined Cycle Process Flow Sheet... Effect of the Prices of Fuel and Electricity on Internal Rate of Return... Effect of the Prices of Fuel and Electricity on Internal Rate of Return... Effect of the Prices of Fuel and Electricity on Internal Rate of Return... Cogeneration by the Integrated Coal Gasification Combined Cycle Process Flow Sheet... Bubble Fluid Bed Steam Boiler System... Circulating Fluid Bed Steam Boiler System V

7 ILLUSTRATIONS 7.3 Cogeneration Petroleum Coke-Fired Atmospheric Fluidized Bed Steam Boilers Heat and Steam Balance--Case 1 Flow Sheet Cogeneration Petroleum Coke-Fired Atmospheric Fluidized Bed Steam Boilers Heat and Steam Balance--Case 2 Flow Sheet Cogeneration Petroleum Coke-Fired Atmospheric Fluidized Bed Steam Boilers Heat and Steam Balance--Case 3 Flow Sheet vi

8 TABLES 2.1 Summary of Cogeneration Economics Major Cogeneration Projects on the U.S. Gulf Coast for Chemical Plants and Petroleum Refineries, Comparison of Topping Cycles In Cogeneration Comparison of System Application and Performance In Cogeneration Summary of Design Capacities and Process Configurations of Study Cases # Estimate Bases and Design Parameters Process Steam from a Packaged Boiler No Cogeneration Case (Base) Estimate Bases and Design Parameters Combined Cycle 1 Cogeneration Case Packaged Boiler and Combined Cycles Summary of Utilities Process Steam Generation by the Packaged Boiler Process No Cogeneration--Base Case Total Capital Investment Cogeneration by the Combined Cycle Process Case l--unfired HRSG Total Capital Investment Cogeneration by the Combined Cycle Process Case S--Partially Fired HRSG Total Capital Investment,,..,...,.,..,..., Cogeneration by the Combined Cycle Process Case J--Fully Fired HRSG Total Capital Investment m Process Steam Generation by the Packaged Boiler Process No Cogeneration--Base Case 5.10 Cogeneration by the Combined Cycle Process Case 1 --Unfired HRSG vii

9 TABLES Cogeneration by the Combined Cycle Process Case P--Partially Fired HRSG Cogeneration by the Combined Cycle Process Case 3--Fully Fired HRSG Operating Costs,.,... Operating Costs and Product Values for Combined Cycles Summary of Combined Cycle Economics Texaco Gasifier Projects Cogeneration by the Integrated Coal Gasification Combined Cycle Process Estimate Bases and Design Parameters Fuel Gas Productlon by Coal Gasification for Combined Cycles 1, 2, and Cogeneration by the Integrated Coal Gasification Combined Cycle Process Combined Cycle l--unfired HRSG Cogeneration by the Integrated Coal Gasification Comblned Cycle Process Combined Cycle P--Partially Fired HRSG Cogeneration by the Integrated Coal Gasification Combined Cycle Process Combined Cycle 3--Fully Fired HRSG Cogeneration by the Integrated Coal Gasification Combined Cycle Process Summary of Estimated Costs Annual Cash Flows and Internal Rates of Return for the Integrated Coal Gasification Combined Cycle Cogeneration Systems w

10 TABLES 7.1 Properties of Petroleum Coke,...,..., Supply/Demand of Petroleum Coke in the United States Examples of Petroleum Coke-Fired Steam Boilers Cogeneration by Coke-fired Atmospheric Fluidized Bed (AFB) Steam Boilers Estimate Basis and Design Parameters Cogeneration by Petroleum Coke-fired Atmospheric Fluidized Bed Steam Boilers Summary of Utility Consumptions,...,.,..., Cogeneration by Petroleum Coke-Fired Atmospheric Fluidized Steam Boilers Case l--low Steam Demand Total Capital Investment Cogeneration by Petroleum Coke-Fired Atmospheric Fluidized Steam Boilers Case 2--Medium Steam Demand Total Capital Investment Cogeneration by Petroleum Coke-Fired Atmospheric Fluidized Steam Boilers Case 3-High Steam Demand Total Capital Investment m Cogeneration by Petroleum Coke-Fired Atmospheric Fluidized Bed Steam Boilers Case l--low Steam Demand Operating Costs..,...,,..., Cogeneration by Petroleum Coke-Fired Atmospheric Fluidized Bed Steam Boilers Case S--Medium Steam Demand Operating Costs..,...,...,..,., ix

11 TABLES 7.11 &generation by Pertoleum Coke-Fired Atmospheric Fluidized Bed Steam Boilers Case 3--High Process Steam Demand &generation by Coke-Fired Atmospheric Fluidized Bed Steam Boilers Annual Cash Flows and Internal Rates of Return X