An absorber is provided for each of the two boiler CID fans. The flue gas from CID fans flowsthrough the one inlet duct and the openspraytower absorber to the stack. A regenerative gasheat exchangers(GGH) are used to reheat the treated flue gas up to 80℃ at 100%TMCR DesignCoal Load(Guarantee Condition)
FOR CONSTRUCTION 19.12.2018 Rev Date Owner K.H.KIM Prepared T.H.HAN Checked H.M.LEE Approved FOR CONSTRUCTION Details of Revision Owner’s Engineer Contractor DOOSAN HEAVY INDUSTRIES VIETNAM Sub-Supplier Project NGHI SON BOT THERMAL POWER PLANT PROJECT Title SYSTEM DESCRIPTION FOR FGD SYSTEM Document No Rev NS2-XS00-P0HT-530001 Page-No SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 RECORD OF REVISION Rev Date A 02.07.2018 B 24.08.2018 19.12.2018 Page Affected Description of Revision First Issue 3, 6, Revised as per comment N/A Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 CONTENTS GENERAL DESIGN DESCRIPTION 1.1 REFERENCE DOCUMENT 1.2 GENERAL DESCRIPTION 1.3 PROCESS CHEMISTRY 1.4 REAGENT CONDITION FLUE GAS SYSTEM 2.1 GAS-GAS HEATER 2.2 DAMPER ABSORBER SYSTEM 3.1 SLURRY SPRAY AND REACTION TANK 3.2 OXIDATION AIR BLOWER 3.3 MIST ELIMINATOR 3.4 GYPSUM BLEED PUMP 3.5 EMERGENCY STORAGE TANK 3.6 ABSORBER AREA SUMP LIMESTONE HANDLING SYSTEM LIMESTONE SLURRY PREPARATION SYSTEM GYPSUM DEWATERING SYSTEM 7 WASTE WATER DISCHARGE 8 GYPSUM DISPOSAL Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 General Design Description This document provides the general system description for Wet Limestone Flue Gas Desulfurization (WLFGD) plant for Nghi Son power Plant (600 MW x 2) utilizes wet limestone slurry with in-situ forced oxidation (IFO) to produce commercial grade gypsum 1.1 Reference Document 1.1.1 Process Flow Diagram 1.1.2 NS2-XG07-P0HT-530001 PROCESS FLOW DIAGRAM FOR FGD SYSTEM NS2-XG07-P0ECD-620001 FLOW DIAGRAM FOR LIMESTONE HANDLING SYSTEM NS2-XG07-P0ECE-620001 FLOW DIAGRAM FOR GYPSUM HANDLING SYSTEM Piping & Instrument Diagram NS2-XG02-P1HT-530100 1.2 P&I DIAGRAM FLUE GAS SYSTEM - FLUE GAS PATH NS2-XG02-P1HT-530101 P&I DIAGRAM FLUE GAS SYSTEM - DAMPER NS2-XG02-P1HT-530200 P&I DIAGRAM ABSORBER & AUX.SYSTEM(1/4) - ABSORBER LIQUID SIDE SHEET(1/2) NS2-XG02-P1HT-530201 P&I DIAGRAM ABSORBER & AUX.SYSTEM(2/4) - ABSORBER LIQUID SIDE SHEET(2/2) NS2-XG02-P1HT-530202 P&I DIAGRAM ABSORBER & AUX.SYSTEM(3/4) - EMERGENCY STORAGE TANK NS2-XG02-P1HT-530203 P&I DIAGRAM ABSORBER & AUX.SYSTEM(4/4) - ABSORBER SLURRY SUMP NS2-XG02-P1HT-530204 P&I DIAGRAM OXIDATION AIR SYSTEM - OXIDATION AIR BLOWER NS2-XG02-P0HT-530301 P&I DIAGRAM LIMESTONE PREPARATION SYSTEM(1/3) - WET BALL MILL A NS2-XG02-P0HT-530302 P&I DIAGRAM LIMESTONE PREPARATION SYSTEM(2/3) - WET BALL MILL B NS2-XG02-P0HT-530303 P&I DIAGRAM LIMESTONE PREPARATION SYSTEM(3/3) - L/S SLURRY STORAGE TANK NS2-XG02-P0HT-530400 P&I DIAGRAM GYPSUM DEWATERING SYSTEM(1/5) - GYPSUM SLURRY STORAGE TANK NS2-XG02-P0HT-530401 P&I DIAGRAM GYPSUM DEWATERING SYSTEM(2/5) - DEWATERING SYSTEM "A" NS2-XG02-P0HT-530402 P&I DIAGRAM GYPSUM DEWATERING SYSTEM(3/5) - DEWATERING SYSTEM "B" NS2-XG02-P0HT-530403 P&I DIAGRAM GYPSUM DEWATERING SYSTEM(4/5) - FILTRATE TANK NS2-XG02-P0HT-530404 P&I DIAGRAM GYPSUM DEWATERING SYSTEM(5/5) - FGD W.W Blowdown Tank NS2-XG02-P0HT-530600 P&I DIAGRAM MAKE UP WATER SUPPLY SYSTEM FOR FGD NS2-XG02-P0HT-530700 P&I DIAGRAM CLOSED COOLING WATER SYSTEM FOR FGD NS2-XG02-P0HT-530810 P&I DIAGRAM SERVICE AIR SYSTEM FOR FGD NS2-XG02-P0HT-530800 P&I DIAGRAM INSTRUMENT AIR SYSTEM FOR FGD NS2-XG02-P0HT-530900 P&I DIAGRAM AUX STEAM SYSTEM FOR FGD NS2-XG02-P0ECD-620001 P&I DIAGRAM FOR LIMESTONE HANDLING SYSTEM NS2-XG02-P0ECE-620001 P&I DIAGRAM FOR GYPSUM HANDLING SYSTEM General Description An absorber is provided for each of the two boiler CID fans The flue gas from CID fans flows through the one inlet duct and the open-spray-tower absorber to the stack A regenerative gas heat exchangers(GGH) are used to reheat the treated flue gas up to 80℃at 100%TMCR Design Coal Load(Guarantee Condition) The flue gas desulfurization system(FGD) is installed for the boiler to meet the required emission limit of 200mg SO2 / Nm3 @ 6%O2, dry for the range of coal One spray bank is installed as Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 online backup Gypsum slurry produced in the absorber is concentrated by the gypsum dewatering system – hydrocyclone The concentrated gypsum slurry underflow from the gypsum dewatering hydrocyclone is fed to a vacuum belt filter directly to produce commercial grade gypsum with less than 13% moisture The overflow from the gypsum dewatering hydrocyclone containing the valuable unreated limestone is returned to the absorber The filtrate receiver water is sent to filtrate tank to make up for absorber & limestone preparation system 1.3 Process Chemistry The main function of the absorber is to remove sulfur dioxide from the flue gas using a slurry pH 5.0 to 6.0 containing calcium carbonate The absorber reaction tank is designed to promote calcium carbonate dissolution and forced oxidation The overall reactions that take place in the absorber are : SO2 (g) + CaCO3 + 2H2O + 1/2 O2 → CaSO4∙ 2H2O + CO2 (g) Many intermediate steps also take place Calcium ions are formed in the aqueous solution CaCO3 (s) → CaCO3 (aq) CaCO3 (aq) + H2O → Ca2+ + HCO3 + OHThe SO32- anions form at the flue gas / liquid interface in the absorber SO2 (g) → SO2 (aq) SO2 (aq) + H2O → H2SO3 → HSO3- + H+ HSO3‐ → H+ + SO3‐ Gypsum, calcium sulfate di‐hydrate, is formed by forced oxidation environment SO32‐ + 1/2 O2 → SO42‐ 2H+ + HCO3‐ + OH‐ → 2H2O + CO2 Ca2+ + SO42‐ + 2H2O → CaSO4·2H2O (s) The sulfite ion also combines with the calcium ion to form calcium sulfite hemihydrate Ca2+ + SO32‐ + 1/2 H2O → CaSO3·1/2 H2O (s) In addition to sulfur dioxide, the absorber also removes hydrogen chloride and hydrogen fluoride from the flue gas Calcium carbonate is required to neutralize these acid gases in the following manner 2HCl + CaCO3 → CaCl2 + H2O + CO2 2HF + CaCO3 → CaFl2 + H2O + CO2 Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 1.4 Reagent Condition The Lime Stone Analysis for design is shown in below Table Trung Nam ① Fecon Hai Dang ② Licogi 13 ③ Design Range Min Max Average Min Max Average Min Max Average CaO 50.12 54.49 53.26 53.69 55.41 54.72 53.58 54.78 54.36 CaCO3 89.5 97.3 95.13 95.88 98.95 97.71 95.68 97.82 97.08 95.13 85.00 Min MgO 0.6 4.44 2.02 0.30 2.60 1.11 0.75 1.40 1.06 2.02 4.73 Max MgCO3 1.26 9.32 4.24 0.63 5.46 2.33 1.58 2.94 2.23 4.24 9.32 Max SiO2 0.17 0.9 0.46 0.08 1.14 0.45 0.24 0.68 0.36 0.46 1.14 Max Fe2O3 0.1 0.48 0.20 Al2O3 0.11 0.23 0.18 0.01 0.05 0.03 0.05 0.11 0.07 Al2O3+Fe2O3 0.21 0.71 0.38 0.01 0.05 0.03 0.05 0.11 0.07 0.38 0.71 Max P2O5 0.043 0.089 0.064 0.009 0.032 0.017 0.003 0.008 0.005 0.064 0.089 Max - Bond work index : 10kWh/Mt(estimated) - Solid limestone(bulk density) : 1,120 Kg/m3 - Solid limestone(for equipment and steel structure) : 1,760 Kg/m3 - Solid limestone size : 0-25mm Flue Gas System Flue gas from the boiler CID fans will be transferred to one (1) GGH (untreated side) The flue gas will then enter the absorber where SO2 is removed And then, from absorber, treated flue gas will flow via the GGH treated side to the stack 2.1 Gas-Gas Heater Flue gas treated by the absorber system will be reheated to prevent visible plume and corrosion of duct and stack and to improve the diffusion efficiency into the atmosphere The GGH is capable of reheating the treated flue gas temperature at the stack inlet without supplemental heat input 2.2 Damper One (1) FGD inlet damper, one (1) FGD outlet damper, one (1) emergency bypass damper and associated damper seal air fans are supplied per unit Inlet damper is equipped with motorized actuator Outlet dampers are also equipped with a motorized actuator Bypass damper is fail open with pneumatic actuator Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 Absorber System Flue gas enters the absorber near the bottom of the spray-tower and flow upward to react with a descending spray of finely divided droplets of recycle slurry counter-currently The slurry contains the alkali needed to react with SO2 Intimate contact of the flue gas with the alkaline limestone slurry is achieved in three successive spray zones Each spray bank is provided with a series of spray nozzles designed to achieve proper atomization of slurry 3.1 Slurry Spray and Reaction Tank Absorber recirculation pumps designed at FGD design point (BMCR Worst Coal Condition) are supplied Four(4) absorber recirculation pumps are installed per each unit Three(3) number of absorber recirculation pumps will be operated and one(1) number of absorber recirculation pump is for stand‐by Each pump is dedicated to each spray stage The absorber reaction tank is designed with a minimum of 15.0 hours solids retention time and adequate agitation to ensure optimum utilization of limestone and crystallization as well as precipitation of gypsum 3.2 Oxidation Air Blower Oxidation of calcium sulfite to calcium sulfate or gypsum is also accomplished in the reaction tank Oxidation air blowers supply the air to lances submerged in the recycle tank for the oxidation reaction Three(3) (100% x 3) oxidation air blowers are provided for the two(2) units The compressed oxidation air is quenched with adequate amount of raw water to avoid nozzle plugging 3.3 Mist Eliminator A two-stage mist eliminator is provided after slurry spray zone, at the top of the absorber The first stage mist eliminator removes the bulk of the entrained liquid droplets from the gas stream The mist eliminators are washed intermittently to maintain clean surfaces and low gas-side pressure losses Mist eliminator wash nozzles are located in the bottom and the top of the first stage mist eliminator and the bottom of the second stage mist eliminator The frequency of the washing cycle is adjustable and is controlled based on the system water demand A mist eliminator wash will utilize the make-up water coming from make up water tank 3.4 Gypsum Bleed Pump Gypsum slurry pump is provided to maintain 20% suspended solids in the absorber The bleed is sent to a gypsum dewatering system The emergency slurry tank is provided for the absorber’s slurry return or gypsum system return for maintenance situation Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 3.5 Emergency Storage Tank One emergency storage tank is provided for both FGD system The emergency storage tank is equipped with an emergency tank pump to reclaim to collected slurry from the emergency storage tank to absorber reaction tank Agitators are provided to keep the slurry solid in suspending during tank usage 3.6 Absorber Area Sump Drainage and flush water from pumps will be collected in the absorber area sump through trenches An absorber slurry sump and absorber area sump pumps is provided for one absorber system An agitator is provided to keep the slurry solid in suspension during tank usage The collected slurry in the absorber area sump will be returned to the absorber reaction tank or to the emergency storage tank Limestone Handling System 25mm size of crushed limestone is delivered to the limestone storage shed by truck The capacity of limestone storage shed was designed to hold days of limestone consumption and in addition two(2) limestone day silos is capable of holding total two(2) days of limestone consumption for two(2) units Limestone from the storage shed is delivered to day silos by unloading hopper, bucket elevators and conveyors Limestone Slurry Preparation System The limestone slurry preparation system includes a ball mill and cyclone classifiers which produce a finely ground limestone slurry at 95% solids passing through 325 mesh The mill slurry tank will send limestone to ball mill classifier to classify big size limestone Then, the overflow of the ball mill classifier shall go to the central slurry tank Limestone slurry in the limestone slurry tank will be pumped to absorber by the limestone slurry transfer pumps Agitators is provided to keep the slurry solids in suspension during tank usage Limestone slurry is added to the absorber to replenish limestone consumed by chemical reaction with the absorbed sulfur dioxide The slurry addition rate is controlled by a pH control system based on the pH in the absorber Gypsum Dewatering System A stream of slurry is taken from the absorber by gypsum slurry pump to remove the gypsum produced as a result of SO2 absorption and oxidation The gypsum bleed from the absorber is fed to the hydrocyclone Hydrocyclone underflow gose to the vacuum belt filter Gypsum cake including maximum 13% water content is produced at the vacuum belt filter Vacuum belt filter system is consist of vacuum receiver, vacuum pump, cake washing system and cloth washing system Produced gypsum is transferred and stored to sypsum storage shed Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001 Separated water by vacuum belt filter, overflow of the first hydro‐cyclone and underflow of the second hydro‐cyclone are collected to filtrate water tank This filtrate water is returned to the wet ball mill system and absorber With this flow, unreacted limestone is sent to the absorber reaction tank to increase limestone utilization Waste Water Discharge Overflow from first hydro‐cyclone is fed to second hydro‐cyclone and filtrate water tank The overflow of second hydrocyclone goes to waste water blow down tank This waste water of FGD system is discharged to FGD waste water treatement system By this discharge flow, chloride concentration in FGD system can be controlled less than 20,000 ppm Gypsum Disposal The gypsum containing less than 13% moisture will be discharged from vacuum belt filter to the gypsum conveyor This dewatered gypsum is transported to the gypsum storage shed The gypsum is temporarily stored in the gypsum shed discontinuously transported to outside of site by owner Rev.0 of ... DIAGRAM MAKE UP WATER SUPPLY SYSTEM FOR FGD NS2-XG02-P0HT-530700 P&I DIAGRAM CLOSED COOLING WATER SYSTEM FOR FGD NS2-XG02-P0HT-530810 P&I DIAGRAM SERVICE AIR SYSTEM FOR FGD NS2-XG02-P0HT-530800 P&I... INSTRUMENT AIR SYSTEM FOR FGD NS2-XG02-P0HT-530900 P&I DIAGRAM AUX STEAM SYSTEM FOR FGD NS2-XG02-P0ECD-620001 P&I DIAGRAM FOR LIMESTONE HANDLING SYSTEM NS2-XG02-P0ECE-620001 P&I DIAGRAM FOR GYPSUM... gypsum dewatering system The emergency slurry tank is provided for the absorber’s slurry return or gypsum system return for maintenance situation Rev.0 of SYSTEM DESCRIPTION FOR FGD SYSTEM NS2-XS00-P0HT-530001