(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date W O 2016/134873 A l 1 September 2016 (01.09.2016) P O P C T (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every C09K 8/528 (2006.01) kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, (21) International Application Number: BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, PCT/EP20 16/0505 11 DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, (22) International Filing Date: HN, HR, HU, ID, IL, EST, IR, IS, JP, KE, KG, KN, KP, KR, 13 January 2016 (13.01 .2016) KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, (25) Filing Language: English PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, (26) Publication Language: English SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (30) Priority Data: 14/634,499 27 February 2015 (27.02.2015) US (84) Designated States (unless otherwise indicated, for every 15000756.5 13 March 2015 (13.03.2015) EP kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, (71) Applicant: CLARIANT INTERNATIONAL LTD TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, [CH/CH]; Rothausstr. 61, 4132 Muttenz (CH). TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (72) Inventors: WYLDE, Jonathan; 54 N Turtle Rock CT, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, The Woodlands, Texas 77382 (US). MAHMOUDKH- SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, ANI, Amir; 131 S Spinning Wheel Circli, The Woodlands, GW, KM, ML, MR, NE, SN, TD, TG). Texas 77382 (US). MILLER, Steven; 961 1 Grant Rd. Apt. 522, Houston, Texas 77070 (US). OKOCHA, Cyril Published: Emeka; 1475 Sawdust road, Apartment #6208, The Wood — with international search report (Art. 21(3)) lands, Texas 77380 (US). (74) Agent: MIKULECKY, Klaus; Clariant Produkte (Deutschland) GmbH, Industriepark Hochst / G 860, 65926 Frankfurt (DE). 00 v (54) Title: LIQUID DISSOLVER COMPOSITION, A METHOD FOR ITS PREPARATION AND ITS APPLICATION IN MET AL SULFIDE REMOVAL o (57) Abstract: The present invention relates to an aqueous composition, comprising 1. 5 to 50 wt.-% of at least one polymeric carboxylic acid having a weight average molecular weight from 1500 to 50.000 g/mol, determined by gel permeation chromato graphy against polystyrene standards, or its salt; 2. 2 to 28 wt.-% of at least one H+ ion releasing monomeric acid having a molecular weight of less than 500 g/mol; 3. 2 to 30 wt.-% of at least one surfactant. Liquid Dissolver Composition, A Method For Its Preparation And Its Application In Metal Sulfide Removal FIELD OF INVENTION The invention described concerns a dissolver composition for sulfide scale minerals, especially sulfides of iron, lead and zinc. The application of this dissolver chemical is particularly suited to oilfield exploration, drilling, production and process systems where sulfide scales have a tendency to form. However there is also applicability to other industries such as mining, refinery and general industry. The application of this dissolver serves to remove these highly insoluble sulfide scales, far more efficiently than other chemicals known in the art. The dissolver composition does not attack the metal surfaces to which the sulfide scale is so commonly adhered. BACKGROUND OF THE INVENTION It has been well documented that sulfide scales of iron, zinc and lead can cause various challenges with process and production in the oil industry. The common impact is the deposition of scales that decrease production capacity. The common metal sulfide minerals are shown in Table . It is also possible for solid solutions to exist between the metal cations that counter the sulfide anion. Accumulation of sulfide scale in the tubulars can result in reduced well deliverability. The build-up of sulfide scale interferes with the operation of pumps, valves and other associated surface equipment. Table 1: The common sulfide minerals Mineral Name Chemical Formula Pyrite FeS2 Marcasite FeS2 Pyrrhotite Fei -xS Troilite FeS Mackinawite FeSi -x Greigite Fe3S4 Kansite FegSs Sphalerite ZnS Galena PbS The surface of sulfide scales is oil-wet (oleophillic), in particular iron sulfide, and free-floating iron sulfide particles are often found at the oil-water interface and stabilize emulsions, thus affecting the separation. Iron sulfide has also been reported as far downstream as the refinery, where it has reduced the efficacy of heat exchange surfaces. Deposition can create an integrity risk; once sulfides form onto metal surfaces, they form a cathode to the equipment surface which yields a significant localized corrosion (pitting) potential. This is commonly exacerbated by the irregular form of the scale surfaces thus accelerating further corrosion. Sulfide scale forms most typically as an H2S corrosion product or from the mixing of incompatible waters. The primary reaction at normal brine pH is: M2+ + H2S (aq) →MS (s) + 2H+ M = Fe, Pb or Zn It has been postulated that iron sulfide scale is predominantly deposited as a result of microbially enhanced corrosion or as a result of the reduction of iron oxide (from corrosion) by hydrogen sulfide, derived from sulfate reducing bacteria (SRB) metabolism. The presence of iron sulfide solids is common in aging assets, as the prevalence of corrosion products, e.g. iron can occur as a result of insufficient corrosion protection. Iron, zinc and lead sulfide solids can also be found in the formation waters associated with certain reservoirs, where high pressure, high temperature and high salinity (HP/HT/HS) conditions are encountered. Removal and prevention of sulfide scales is challenging. Part of the reason for this is the extremely low solubility products (Ksp) associated with sulfide scales, due in part to the highly covalent nature of transition metals sulfides; Table 2 shows the solubility products of the most common sulfide minerals in comparison with common, conventional scales. Table 2 : Solubility product constants for a selection of common inorganic mineral scales and sulfide scales found in oil and gas production (Dean, 1999) at 25 °C. Existing methods of remediation available to treat sulfide scale deposits comprise both mechanical and chemical. Mechanical remediation by way of jetting is possible, if the areas affected by mineral scale build up are readily accessible. Pipework with more tenacious deposits may require more aggressive milling operations. Both options incur costs in terms of deferred oil production and equipment rental. Chemical mitigation strategies for sulfide scales can be divided into two categories: removal and dissolution or control and prevention. Techniques and chemicals for the removal and dissolution of sulfide scales have been documented in the literature. The most commonly performed technique has been to use hydrochloric acid, but it has been reported to perform with varying degrees of success. It has been noted for example that iron sulfide with lower amounts of sulfur has a higher solubility in acid. Challenges using hydrochloric acid are encountered due to the potentially high yield of H2S upon dissolution of the scale; additionally hydrochloric acid is very corrosive. This has led to research on the inclusion of corrosion inhibitors and scavengers into the acid blend. Other components have been reported in the formulations such as chelants, wetting agents, solvents, iron control agents, anti-sludge agents - all these components were included on the basis that sulfide scales are often associated with oil and biomass which act as a diffusion barrier that inhibit the acidic reaction. An alternative approach to acids is the use of strong oxidizing agents which avoids the toxicity hazards of acids but produces oxidation products, including elemental sulfur, which are so corrosive to pipework that is has not generally been practiced. Due to the challenges associated with use of acids, the focus in the last decade has turned to alternative, non-acidic dissolver chemistries. These include chelating agents such as ethylenediamine-tetra-acetic acid (EDTA), diethylene-triamine- penta-acetic acid (DTPA), hydroxyethylene-diamine-tetra-acetic acid (HEDTA) or nitilotriacetic acid (NTA). The efficacy of chelating agents, however, has been shown to be relatively limited, as they function poorly in acidic environments, requiring elevated pH for full dissociation and efficacy. Acrolein gas is effective for iron sulfide dissolution but is a challenging material to handle due to the severe health, safety and environmental problems that it gives rise to. Acrolein reacts with iron sulfide to form an intermediate compound that is far less likely to re-deposit, and at the same time, the acrolein will also scavenge H2S. Tetrakis(hydroxymethyl) phosphonium sulfate (THPS) has been reported as effective against iron sulfide scales. THPS dissolves via a chelation method and the efficacy is vastly improved with inclusion of ammonium ions (where an intermediate complex is formed) or DETA-phosphonate is added; however when tested in a pressurized system, the efficacy of THPS-based dissolvers decreased. One of the additional advantages of THPS is that it can be used to remove deposits via continuous injection of very low concentrations. The process and science behind control and prevention of iron sulfide is much more complex than removal and dissolution. All facets are more complex, whether it is laboratory testing, implementation in the field or the mechanism of inhibition.